Note: Descriptions are shown in the official language in which they were submitted.
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SPA HALOGEN GENERATOR
Backuround of the Invention
Field of the Invention
The present invention relates to a water purification system, and more
particularly to a halogen generator.
Description of Related Art
Portable self-contained spas have become popular in recent years. Such spas
are easy installed and
powered by existing electrical lines or dedicated electrical hook-ups.
Once installed, the homeowner must sanitize the spa to prevent the
proliferation of disease-causing micro
organisms, such as, for example, Pseudomonasaeruginosa. Typical spa
maintenance requires adding granular sodium
dichloro-iso-cyanurate as a sanitizing agent to control such bacteria growth.
Bromine alternatively can be added as
a sanitizing agent. Bromine preferably is used as the sanitizing agent in the
spa because it remains in liquid form
at 100oF, unlike chlorine.
Many spa owners today, however, do not properly maintain their spas. Some
owners do not adequately
sanitize their spas despite the danger of unhealthful bacteria growth. Other
owners over sanitize their spas which
can damage spa equipment, including the heater or the spa shell.
In the pool industry, some pool owners recently have used electrolytic cells
with their pool or spa to
produce chlorine or bromine automatically by electrolysis. Such electrolytic
cells eliminate the need to constantly
adjust the chlorine or bromine levels by adding chemicals to the pool.
Examples of electrolytic cells used to generate
sanitizing agents are disclosed in U.S. Patent Nos. 4,992,156, 4,790,923, and
4,201,651.
Although such electrolytic cells simplify the proper maintenance of chemical
levels in the pool, other
problems arise in connection with their use. Many pool owners commonly neglect
the filtration system of the pool,
which, as a result, clogs and reduces the flow rate through the water
circulation line. Because prior electrolytic cells
commonly are connected in series with the main spa circulation line and depend
on a minimum flow rate through the
cell, the effectiveness of the cell decreases. In addition, an insufficient
flow rate through the cell may present the
potential for explosion as such cells commonly produce hydrogen and oxygen
gases which become entrapped within
the cell if not flushed into the pool by water flow through the cell.
Scaling or plating out of calcium carbonate and other salts on the cathode of
the electrolytic cell during
operation presents another formidable maintenance problem associated with
electrolytic units used in hard water.
In water having a hardness greater than 700 parts per million ("hard water"),
scale deposits from the water and
builds up on surfaces adjacent to a water flow. Electrolytic cells used in
hard water commonly experience significant
scale build-up which causes water flow problem. Scale typically builds up and
clogs small openings and conduits
in the equipment. Thus, some manufacturers recommend using their equipment in
water having a total hardness less
than 300 parts per million.
Other manufacturers of electrolytic cells have attempted to resolve the
problems associated with scaling
in a variety of ways; however, prior attempts offer less than an adequate
solution. Prior electrolytic cells which
reverse the polarity of the electrodes to remove scale tend to have shortened
electrode life. Other electrolytic cells
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have relied on high flow water rates through the cell to remove scale, but
flow through the cell may be affected
by the inefficiency of an external pump or by a clogged filter. And some
manufacturers recommend manually
cleaning of the cell electrodes by soaking them in acid. Although effective,
this process is dangerous, time-
consuming, and may not be feasible, given the industry trend toward limiting
consumer access to the spa equipment.
Summary of the Invention
In view of the deficiencies associated with prior electrolytic cell devices,
there exists a need for a halogen
generator for use with portable spas and other water features which is highly
resistant to the formation of
undesirable scale deposits on the electrodes resulting from operation in hard
water andlor high temperatures and
which eliminates the need to reverse electrode polarity as a means for
removing scale deposits on the cathode. A
need also exists for a halogen generator which operates independently of a
water circulation pump of the water
feature (e.g., the spa).
In accordance with an aspect of the present invention, a halogen generator
produces a halogen sanitizing
agent in a body of water of a water feature. The generator comprises a cathode
and an anode which are spaced
apart from each other within a housing. At least one vane is positioned
between the cathode and anode. The vane
and the cathode are mounted to rotate relative to each other with the vane
being sufficiently closely spaced to the
cathode to inhibit scale formation on the cathode. The vane, however,
generally does not contact the cathode.
Another aspect of the present invention involves a halogen generator for
producing a halogen sanitizing
agent in a body of water of a water feature. The halogen generator comprises a
bipolar cell which includes at least
one electrode positioned between an outer anode and an outer cathode. The
electrode is mounted to rotate relative
to the anode and to the cathode. A source of electricity is connected to the
anode and to the cathode without
connection to the rotary electrode.
An additional aspect of the present invention involves a spa system which
comprises a spa body, a pump,
and a main water circulation line for conveying water from the pump to the spa
body. The main line communicates
with the spa body through at least a return port. A bypass line communicates
with the main circulation line through
at least an inlet to the bypass line. A check valve is positioned in the main
line between the bypass inlet and the
return port. The spa system also includes an electrolytic cell which
communicates with the bypass line.
In accordance with a further aspect of the present invention, a spa system
comprises a spa body, a first
water circulation line, and a second water circulation line. The first water
circulation line communicates with the
spa body. The second water circulation line also communicates with the spa
body, but independent of the first
water circulation line. The spa system also includes a pump positioned within
the first water circulation line and
a halogen generator positioned in the second water circulation line. The
halogen generator comprises an electrolytic
cell.
An additional aspect of the present invention involves a fitting for coupling
a halogen generator to a spa
body. The fitting comprises an inner member positioned within the spa body and
an outer member positioned outside
the spa body. The inner and outer members are adapted to releasably engage
each other with a wall of the spa
body interposed between the inner and outer members. The inner and outer
members together define first and
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second conduits which communicate with the spa body. The outer member has a
first port which
is adapted to communicate with an inlet of a halogen generator and a second
port which is
adapted to communicated with an outlet of the halogen generator. The first
port communicates
with the first conduit defined between said inner and outer members, and the
second port
communicates with the second conduit defined between the inner and outer
members.
Another aspect of the present invention involves a wall fitting for a spa. The
fitting
comprises a first tubular member connected to a translucent end cap. The first
tubular member
and the end cap together define a fluid passage which extends through the
first tubular member
and the end cap. A second tubular member is positioned about the first tubular
member and is
connected to the end cap so as to define a generally sealed chamber at the end
of the second
tubular member adjacent to the end cap. An optical source is positioned within
the chamber
defined between the first and second tubular members so as to be visible
through the end cap
when lit.
Another aspect of the present invention involves a method of inhibiting scale
buildup in
an electrolytic cell between two electrodes separated by a space. Water is
flowed through the
space between the electrodes in a first direction while operating the cell.
The direction of the
water flow between the electrode is then reversed to displace a substantial
portion of scale
deposits on the electrode.
In accordance with a preferred method of inhibiting scale buildup between two
spaced
electrodes, at least one abrading member is positioned between the electrodes.
The abrading
member is spaced from a first electrode of the electrode pairing by a first
distance. The abrading
member is rotated with respect to the first electrode, and the space between
the abrading
member and the first electrode is decreased. In this manner, the abrading
member contacts and
knocks off scale buildup on the electrode. The abrading member preferably is a
vane or a tab
which protrudes toward the first electrode.
An additional aspect of the present invention relates to a method of operating
a halogen
generator which includes an electrolytic cell mounted in a water circulation
line of a water
feature. The method involves sensing the ionic potential of the water within
the water circulation
line and determining whether the sensed ionic potential is below a pre-
determined ionic potential
level. An activation signal is generated if the sensed ionic potential is less
than the pre-
determined ionic potential level. An electrolytic cell is energized in
response to the activation
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signal, and a water flow is produced through the electrolytic cell while the
electrolytic cell is
energized.
In accordance with another aspect or illustrative embodiment of the invention,
there is
provided a halogen generator for producing a halogen sanitizing agent in a
body of water of a
water feature. The generator includes a cathode and an anode which are spaced
apart from
each other within a housing, the cathode and anode having planar shapes, and
at least one vane
positioned between the cathode and anode. The vane and the cathode are
supported to rotate
relative to each other with the vane being sufficiently closely spaced to the
cathode to inhibit
scale formation on the cathode but not contacting the cathode. The vane
rotates about an axis
which is generally perpendicular to the plane of the cathode.
In accordance with another illustrative embodiment of the invention, there is
provided a
halogen generator for producing a halogen sanitizing agent in a body of water
of a water feature.
The halogen generator includes a bipolar cell including at least one electrode
positioned between
an outer anode and outer cathode. The electrode is mounted to rotate relative
to the anode and
the cathode and is spaced from the cathode by a distance not greater than 0.15
inch so as to
inhibit scale formation on the cathode without contacting the cathode. The
generator further
includes a source of electricity connected to the anode and the cathode
without connection to the
rotary electrode.
In accordance with another illustrative embodiment of the invention, there is
provided a
halogen generator for producing a halogen sanitizing agent in a body of water
of a water feature.
The generator includes a first electrode and an impeller which have generally
parallel, opposing
surfaces. The impeller is rotatable to motivate water flow between the
electrode and the
impeller, and is sufficiently closely spaced to the electrode to inhibit scale
formation on the
electrode without contacting the electrode. The surface of the impeller lies
generally parallel to
the surface of the electrode as the impeller rotates relative to the
electrode.
In accordance with another illustrative embodiment of the invention, there is
provided, in
an electrolytic cell, a method of removing scale buildup between two spaced
electrodes. The
method includes positioning at least one abrading member between the
electrodes, the abrading
member being spaced from a first electrode of the electrodes by a first
distance. The method
further includes rotating the abrading member with respect to the first
electrode, and decreasing
the space between the abrading member and the first electrode while
maintaining a gap between
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the abrading member and the first electrode, whereby the abrading member
contacts and
dislodges scale formation on the first electrode without contacting the first
electrode.
In accordance with another illustrative embodiment of the invention, there is
provided, in
an electrolytic cell used in an aqueous solution, a method of removing scale
buildup between first
and second electrodes separated by a space. The method includes attaching at
least one
projection to the first electrode, and juxtaposing the first and second
electrodes with the
projection position within the space between the first and second electrodes
such that a gap is
formed between the projection and the second electrode. The method further
includes rotating
the first electrode in a first direction relative to the second electrode to
produce a flow of water in
a first general direction in the space between the electrodes, and reversing
the rotation of the
first electrode relative to the second electrode to produce a flow of water
within the space in a
second general direction, which is generally opposite to the first general
direction.
In accordance with another illustrative embodiment of the invention, there is
provided, in
an electrolytic cell used in an aqueous solution, a method of inhibiting scale
formation between
first and second electrodes separated by a space. The method includes rotating
the first
electrode relative to the second electrode, and maintaining the space between
the first electrode
and the second electrode less than 0.1 inches. The method further includes
changing the water
velocity across the distance from the rotational velocity of the first
electrode to a relative zero
velocity on the surface of the second electrode, and producing a force from
water flow over the
second electrode to inhibit scale buildup on the second electrode.
In accordance with another illustrative embodiment of the invention, there is
provided, in
an electrolytic cell used in an aqueous solution, a method of inhibiting scale
buildup on a first
electrode plate. The method includes juxtaposing at least one abrading member
with the first
electrode plate, and maintaining a gap spacing between the abrading member and
the first
electrode plate of no less than 0.03 inches. The method further includes
rotating the abrading
member over the first electrode plate, and producing a turbulent water flow
over the surface of
the first electrode plate to generally inhibit scale buildup on the first
electrode plate.
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Brief Description of the Drawings
These and other features of the invention will now be described with reference
to the
drawings of preferred embodiments which are intended to illustrate and not to
limit the invention,
and in which:
Figure 1 is an exploded perspective view of a halogen generator configured in
accordance with a preferred embodiment of the present invention;
Figure 2 is an exploded perspective view of an electrolytic cell of the
halogen generator
of Figure 1 wherein a rotating bipolar electrode is positioned between a non-
rotating anode and a
non-rotating cathode;
Figure 2a is a top plan view of the bipolar electrode of Figure 2;
Figure 3 is a plan view of an alternative cathode plate for use with the
halogen generator
of Figure 1;
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Figure 4 is a perspective view of an alternative cathode for use with the
halogen generator of Figure 1;
Figure 5 is a bottom plan view of an alternative volute for use with the
cathode of Figure 4;
Figure 6 is an exploded perspective view of a halogen generator configured in
accordance with another
preferred embodiment of the present invention; -
Figure 7 is an exploded perspective view of an another electrode assembly for
use with the halogen
generator of Figure 6, wherein a rotating anode is positioned between two non-
rotating cathodes;
Figure 8 is an exploded perspective view of an additional electrode assembly
for use with the halogen
generator of Figure 6 wherein a rotating anode is positioned adjacent a non-
rotating cathode;
Figures 9a through 9d are block diagrams of alternative installation
configurations of the present halogen
generator into an existing spa system;
Figure 10 is a schematic representation of a spa water circulation system
utilizing the present spa halogen
generator;
Figure 11 is a schematic representation of an alternative configuration of the
water circulation system of
a spa incorporating the present spa halogen generator;
Figure 12a is a sectional perspective view of an assembled T-connection
fitting between the halogen
generator, spa pump and heater of the spa system;
Figure 12b is an exploded view of a bypass check valve and T-connection
fitting of Figure 12a;
Figure 13a is an exploded perspective view of a coaxial wall mount fitting
assembly configured in
accordance with a preferred embodiment of the present invention;
Figure 13b is an exploded perspective view of a coaxial wall mount fitting
assembly configured in
accordance with another preferred embodiment of the present invention;
Figure 13c is an assembled perspective view of the coaxial wall mount fitting
assembly of Figure 13b;
Figure 14 is an exploded perspective view of a wall mount fitting assembly
configured in accordance with
another preferred embodiment of the present invention;
Figure 15 is a cross-sectional view of a scale trap for use with the present
halogen generator;
Figure 16a is a block diagram of a spa halogen generator control system
utilizing a DC motor;
Figure 16b is a block diagram of a spa halogen generator control system
utilizing an AC motor;
Figure 17a is a flowchart of a timed sequence operating cycle of a spa halogen
generator controller; and
Figure 17b is a flowchart of a sensor-activated operating cycle of the spa
halogen generator controller.
Detailed Description of the Preferred Embodiments
Figure 1 illustrates a halogen generator 20 configured in accordance with a
preferred embodiment of the
present invention. The halogen generator 20 electrolytically generates
chlorine, bromine, or other halogens from a
corresponding dilute solution of halide (e.g., sodium chloride, sodium
bromide, etc.). In this manner, the halogen
generator 20 can be used to produce a pH neutral halogen (e.g., bromine) which
operates as a sanitizing agent in
a body of water as known in the art.
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The present halogen generator 20 is particularly well suited for use with
portable, self-contained spas (e.g.,
Jacuzzis°). It is contemplated, however, that the present halogen
generator 20 can be used with other types of
water features, such as, for example, swimming pools, built-in spas, water
fountains, industrial cooling towers and
the like. The arrangement of the generator 20 with and the fittings used to
incorporate the generator 20 into such
water features will be described below, after a detailed description of the
halogen generator 20 itself.
As seen in Figure 1, the halogen generator 20 principally comprises a cell
assembly 22 formed by an
electrolytic cell 24 and a volute assembly 26 which houses the cell 24. A
motor 28 drives an impeller 30 of the
cell assembly 21 to create a flow of water through the cell 24, as described
below.
The halogen generator 20 also cooperates with a power supply controller 32.
The controller 32 controls
the operation of the electrolytic cell 24 and the motor 28. The individual
components of the halogen generator 20
will now be described in detail with reference to Figures 1 and 2.
Volute Assembly
The volute assembly 26 comprises a volute 34 and a volute plate 36 which
together define an internal
cavity in which the electrolytic cell 24 is housed. The volute 34 includes a
generally cup-shaped housing 38 with
a central cavity 40 having a cylindrical shape. The volute 34 also includes a
plurality of lugs 42 which extend
outwardly from the housing 38. A bolt hole 44 passes through each lug 42.
As understood from Figure 1, the volute 34 includes an inlet port 46 and an
outlet port 48. The inlet port
46 is configured to direct water flow into the central cavity 40 at the center
of the cavity 40. The outlet port 48
is positioned on the peripheral edge of the housing 38, generally tangentially
to the cylindrical central cavity 40 of
the housing 28. This position of the outlet port 48 encourages water flow
through the volute 34, as known in the
art.
In the illustrated embodiment, the volute water inlet 46 includes a tubular
segment 50 which extends axially
from the center of the volute 34 and supports a bib 52. The bib 52 extends
generally perpendicular to tubular
segment 50. A water inlet conduit 54, which communicates with the water
feature (e.g., the spa circulation
system), is attached to the inlet port bib 52 to supply water to cell assembly
22.
The bib 52 communicates with the tubular segment 50 to form an inlet flow path
though the inlet port 46.
So configured, the flow path through the inlet port 46 turns 90~ from the bib
52 into the tubular segment 50 to
direct the flow of water into the cylindrically shaped central cavity 40 at
the center of the cavity 40 and in a
direction along the axis of the cavity 40.
As seen in Figure 1, a plug 56 seals an outer end of the tubular segment 50.
The plug 56 desirably has
a tubular shape which allows a central terminal post 58 of the electrolytic
cell 24 to extend through and out of the
plug 56, as described below. The plug 56 desirably includes an 0-ring (not
shown) which sits against the terminal
post 58 such that the plug 56 forms a seal between the tubular segment 50 and
the cell terminal post 58 to prevent
water flow through the outer end of the tubular segment 50. The plug 56 thus
seals the fluid path through the inlet
port 46.
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The volute plate 36 of the volute assembly 26 includes a disc-shaped body 60
with raised central portions
62, 64 on either side of the body 60. The inner central portion 62 on the
inner side of the volute plate 60 (i.e.,
the side which mates with the volute 24) desirably has a shape which is sized
to snugly fit within the central cavity
40 of the volute 24. In the illustrated embodiment, the inner portion 62 has a
cylindrical shape of a diameter which -
generally matches the diameter of the inner cavity. In this manner, the
central portion 62 generally closes and seals
the open end of the volute 34 so as to form the interior cavity of the cell
assembly 22.
With reference to Figure 2, the outer central portion 64 of the volute plate
36 has a size and shape to
generally match that of an end of the motor 28. In the illustrated embodiment,
the outer central portion 64 has a
disc-like shape of a smaller diameter than the body 60 of the volute plate 36.
The body 60 and the outer central portion 64 of the volute plate 36 together
define at least a pair of holes
which extend into the volute plate 36 from its outer side. The holes are sized
to receive threaded inserts 66 that
are used to attach the motor 28 to the volute plate 36, as described below.
The threaded inserts 66 desirably
consist of stainless steel and are cemented to or integrally molded into the
volute plate 36. In the illustrated
embodiment, the holes lie on diametrically opposite sides of the center of the
volute plate 36.
The volute plate 36 also defines a central bore 70 through its axial center
with a first counterbore 72
circumscribing the bore 70 on the inner side of the plate 36. The counterbore
72 forms a seat for a conventional
mechanical pump seal 74, as described below. A second counterbore (not shown)
extends into the outer central
portion 64 to form a relief.
The volute plate 36 also includes a circular groove 76 in the flange 78 which
circumscribes the inner central
portion 62. The groove 76 provides a seat for an 0-ring (not shown). When
assembled, the volute 34 and volute
plate 36 compress the 0-ring between an end of the volute 34 and the outer
flange 78 to seal the union between
these components.
A plurality of bolt holes 80 extend through the volute plate 36 about the
peripheral edge of the outer flange
78. The bolt holes 80 desirably align with the corresponding bolt holes 44
formed in lugs 42 of the volute 34. A
plurality of fasteners (e.g., bolts and nuts) pass through the aligned bolt
holes 44, 80 and attach the volute plate
36 to the volute 34 when assembled.
The volute plate 36 also includes a hole 82 which extends though the inner
central portion 62 and the disc
body 60 at a location within the 0-ring groove 76. The hole 82 is sized to
receive a terminal post 84 of an
electrode of the electrolytic cell 24, as described below.
The volute 34 and volute plate 36 desirably are formed of a nonconductive
polymer, such as, for example
acrylonitrile-butadiene-styrene (ABS). These components can be constructed in
any of a wide variety of ways which
will be well known to one skilled in the art. For example, these components
can be integrally molded such as by
injection molding.
Drive Motor
Figure 1 also illustrates the electric motor 28 which rotates the impeller 30
of the electrolytic cell assembly
22. The motor 28 may operate on either alternating or direct current (i.e.,
either an AC or DC motor) and desirably
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produces about 8 ounce-inches of torque or greater at a rotational speed of
about 1,800-1,850 rpm. In the
illustrated embodiment, the motor 28 is a 12 volt DC, 16 Watt motor with a
diameter of about 1.6 inches. It is,
of course, understood that those skilled in the art can readily select a
variety of conventional motors of various sizes
and rotational speed and torque specifications in order to suit a specific
application of the generator.
Direct current motors have the advantage of very high starting torque and low
cost. Either brush or
brushless designs can be used with the present halogen generator 20. Motor
speed can be any speed resulting in
the requisite outlet water pressure. One thousand to five thousand rpm is
sufficient. Erosion of the catalytic coating
due to high velocity can be held to a minimum by turning the impeller 30 at
1,500 to 3,000 rpm. At 1,500 rpm,
the tip speed is roughly 487 cm per second, which is not excessive for
electrode coatings. As discussed in detail
below, the actual velocity the anode experiences is substantially less than
that because the water is accelerated to
a speed close to that of the impeller 30, with only the cathode being exposed
to the high-velocity water.
The motor 28 includes a drive shaft 86 which extends into the internal cavity
of the volute assembly 22
when assembled. In the illustrated embodiment, the drive shaft 86 comprises
316 stainless steel.
The end of the drive shaft 86 includes a shoulder 88 and a threaded stud 90.
The shoulder 88 is
configured such that the impeller 30 of the electrolytic cell assembly 22 sits
on the shoulder 88 of the drive shaft
86 when assembled. As understood from Figure 1, the threaded stud 90 desirably
includes a pair of opposing flats
which extend axially from the shaft end toward the motor 28. The resultant
truncated circular cross-sectional shape
of the stud 90 corresponds to a similar shape of a central aperture in the
impeller 30 to key the impeller 30 to the
shaft 28, as described below.
A nonconductive cap nut 92 secures the impeller 30 to the drive shaft 28. The
cap nut 92 desirably is
made of 20°!o glass-filled polycarbonate or like nonconductive,
corrosion-resistant material. The nonconductive cap
nut 92 insulates the shaft 28 from the upper conductive surface of the
impeller 30. In this manner, the shaft 86
is cathodically protected from corrosion as it only contacts one side (i.e.,
the underside) of the impeller 30, as
explained further below.
As understood from Figure 1, the motor 28 also includes a pair of mounting
holes which extend
longitudinally through the body of the motor 28. The mounting holes are sized
to receive mounting bolts 94 which
extend through the motor body and engage the threaded inserts 66 of the volute
plate 36. In this manner, the motor
28 is secured to the volute assembly 26.
Electrolytic Cell
The electrolytic cell 24 includes at least one cathode 96 and at least one
anode 98 which form an electrode
pairing. In the illustrated embodiment, the cell 24 desirably includes two
electrode pairings configured in a bipolar
arrangement. That is, the cell 24 includes a cathode 96, an anode 98, and a
bipolar electrode 30 (which functions
as the impeller) interposed between the cathode 96 and the anode 98. The
cathode 96 and the anode 98 polarize
the corresponding sides of the electrode 30 such that one side of the
electrode 30 function as an anode and the
other side functions as a cathode to provide two cathodelanode pairings. As
illustrated by the other embodiments
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of the electrolytic cell described below, however, any of a wide variety of
cell configurations, which will be readily
apparent to those skilled in the art, can be used with the present halogen
generator 20.
Figure 2 illustrates the electrolytic cell 24 in isolation. The bipolar cell
24 comprises the bipolar electrode
30 positioned between the cathode 96 and the anode 98. In the illustrated
embodiment, the bipolar electrode 30, .
cathode 96, and anode 98 each have generally circular, disc-like shapes and
are arranged in parallel along the
common central axis 100. The electrode 30, the cathode 96, and the anode 98
desirably have a diameter of less
than about 10 inches, more preferably less than about 5 inches, and most
preferably equal to about 2.5 inches.
It is understood, however, that the electrode 30, cathode 96 and anode 98 can
have any of a variety of other
diameter sizes in order to suit a specific application and in order to give
the anode 98 and cathode 96 a proper
current density.
As described in detail below, both the cathode 96 and the anode 98 are mounted
in a fixed rotational
relationship within the cell assembly 22, while the bipolar electrode 30
rotates therebetween. In this manner, the
bipolar electrode 30 functions as a pump impeller as described below.
The cathode 96 includes a circular plate 102 that defines a central bore 104
for the passage of water from
, the water inlet 46 of the volute 34 through the plate 102. The cathode plate
102 is made of an electrically
conductive, corrosion resistant material. In the illustrated embodiment, the
cathode plate 102 is made of 316L
stainless steel or any other suitable metal, such as, for example copper or
titanium. The cathode plate 102,
however, also can be formed of a discontinuous material for enhancing scale
removal from the cathode 96.
As seen in Figure 3, the cathode plate 102 may comprise a plurality of
radially extending fingers 106 of
conductive material separated by gaps. The gaps are filled with an
electrically inert potting material 108, such as
epoxy, which gives the cathode plate 102 a generally flat circular disc-like
shape defined by a plurality of intermittent
finger 106 around the circumference thereof. Interlocking inserts (not shown)
also could fill the gaps to prevent scale
deposits from bridging the gaps.
As the scale develops on the fingers 106, the rotating bipolar electrode 30,
and more particularly the vanes
andlor tabs on the electrode 30, act to abrade the scale. Because the plate 30
is not a continuous circular disc,
the scale forms discontinuously rather than monolithically around its
circumference and thus is easier to remove.
That is, the discontinuity of the scale formation allows the abrading surfaces
le.g., vanes) of the rotary electrode
to "get under" the scale deposit and remove it.
With reference back to Figure 2, the thickness of the cathode plate 102
desirably ranges between about
30 0.020 and about 0.250 inches, and preferably equals about 0.032 inches. A
thinner cathode plate has more
flexibility than a thicker plate, and flexure of the plate 102 tends to
promote scale removal. In addition, in the case
where the cathode plate 102 moves away from the volute 34, as described below,
the surface of the cathode plate
102 which faces the volute 34 preferably is coated to prevent scale buildup
thereon. The side of the cathode plate
102 which faces the bipolar electrode 30, however, desirably is uncoated and
can be polished to an Ra surface finish
of 8 to 16, which has been found to reduce scale formation on this inner
surface of the cathode plate 102.
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The cathode 96 desirably includes the terminal post 58 which is electrically
connected to the cathode plate
102. The terminal post 58 has a diameter of approximately 0.125 inches or
larger; however, it is understood that
the post 58 can have any of a variety of diameter sizes in order to suit a
specific application. As understood from
Figure 1, the terminal post 58 has a sufficient length so as to extend through
the plug 56 to expose its outer end.
The cathode plate 102 desirably can move axially (i.e., in a direction
parallel to the central axis 100) to
enhance descaling of the cathode plate 102, as explained below. The cathode
plate 102, however, preferably is
biased into a desired position for normal operation. For this purpose, the
cathode may comprise a biasing element
or mechanism 110, such as a spring, which biases the cathode plate 102 into a
first position for normal operation
of the halogen generator 20 but allows the plate 102 to move to a second
position to aid descaling of the cathode
plate 102. In the illustrated embodiment, the spring has a spring constant of
about 12 pounds/inch, where the
normal flow rate through the volute assembly 26 is 1.1 gallonslmin. and the
flow rate during a cleaning cycle is 1.7
gallonslmin. It is appreciated, however, that those skilled in the art will be
able to calculate the desired spring
constant for a specific application.
In the illustrated embodiment, the terminal post 58 is welded to a disc 112
which, in turn, is welded to
the spring 110. The spring 110 provides an electrical connection between the
terminal post 58 and the cathode
plate 102, as well as allows relative movement of the cathode plate 102 toward
the bipolar electrode 30, as
discussed below. The spring 110 is welded to the cathode plate 102, about the
bore 104. Heliarc welding is the
preferred method of connecting the spring 102 to the plate 102 as it causes
little deformation of the electrode plate
102. The disc 112 and spring 110 desirably have a diameter of a sufficient
size to stably support the terminal post
58 above the plate 102, yet, as understood from Figure 1, fit within the
tubular segment 50 of the inlet port 46.
Figure 4 illustrates another biasing mechanism 110 which can be incorporated
with the cathode plate 102.
Like reference numerals will be used between like parts of the two cathode
embodiments for ease of understanding.
As with the cathode illustrated in Figure 2, the cathode 96 illustrated in
Figure 4 includes a spring 110 which
couples the terminal post 58 and the disc 112 to the cathode plate 102. The
spring 110, however, is integrally
formed from the central region of the plate 102, rather than being a separate
helical spring, as in the embodiment
illustrated in Figure 2. The spring 110 desirably is a spiral pattern cut from
the center of the cathode plate 102.
In this manner, the spring 110 and the bore 104 are simultaneously formed. The
cathode plate 102 also includes
a pair of outwardly extending tabs 114.
The present cathode 96 can be used with a modified volute, which is
illustrated in Figure 5. The volute
is identical to the volute 34 described above in connection with Figure 1,
with the addition of a pair of diametrically
opposed grooves 116 for receiving the tabs 114 on the cathode plate 102. A
stop (not shown) positioned within
the grooves 116 limits the axial movement of the tabs 114, and thus the
cathode plate 102. The stop may be
formed by affixing a small rod within the grooves 116 at a predetermined
location. The cathode 102 thus is allowed
to "float" to a certain degree within the cell assembly 22 in order to enhance
scale removal, as described below.
The tabs 114 and the stops, however, prevent the cathode plate 102 from
contacting the rotary electrode 30. In
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the illustrated embodiment, the movement of the cathode plate 102 is such that
it may approach within about 0.010
inches to about 0.060 inches with respect to any portion of the rotary
electrode 30.
With reference back to Figure 2, the anode 98 also comprises a circular disc
or plate 118 which includes
a central bore 120. The bore 120 receives the drive shaft 86 of the motor 28
when the cell assembly 24 is
assembled, as described below.
The anode plate 118 is preferably made of titanium or any other suitable
metal. The thickness of the
anode plate 118 desirably ranges between about 0.020 and about 0.250 inches,
and preferably equals about 0.032
inches. The anode plate 118 is coated with precious metal oxides or other
materials, such as, for example, a mixture
of ruthenium oxide and titanium oxide, to promote the production of halogens
through electrolysis.
The anode also includes the terminal post 84 which is electrically connected
to the anode plate 118. The
terminal post 84 is positioned on the plate 118 so as to extend through the
volute plate hole 82 (Figure 1) when
assembled.
The post 84 has a diameter of about 0.125 inches or larger, and is welded to
an outer edge of the anode
plate 118. It is understood, however, that post 84 can have any of a variety
of diameter sizes in order to suit a
specific application. As understood from Figure 1, the terminal post 84 has a
sufficient length so as to extend
through the hole 82 in the volute plate 36 to expose its outer end.
As seen in Figure 2, a stationary vane or baffle 122 extends out of the plane
of the anode plate 118. The
baffle 122 can be either integrally formed with or separately formed from the
anode plate 118 and is positioned to
extend radially across the plate 118. In the illustrated embodiment, the
baffle 122 comprises an integral tab which
is bent out of the plane of the plate 118 to lie at an angle transverse to the
plane of the plate 118.
Figure 2 also illustrates the bipolar electrode impeller 30 of the
electrolytic cell 24. The bipolar electrode
includes a circular disc 124 which preferably is made of titanium or any other
suitable material. Various suitable
coatings (e.g., precious metal oxides) for promoting the electrolytic
production of halogens may be applied to the
exterior surfaces of the bipolar electrode body 124. In the illustrated
embodiment, the electrode disc 124 is coated
25 with a mixture of ruthenium oxide and titanium oxide.
The electrode 30 is attached to the end of the motor drive shaft 86 so as to
rotate between the anode
and cathode plates 98, 96. In the illustrated embodiment, the disc 124
includes a central aperture 126 which has
a complementary shape to the shape of the stud 90 on the end of the drive
shaft 86. That is, the aperture 126
generally has a circular shape with a pair of opposing flats which gives the
aperture 126 a generally flatten-elliptical
30 shape.
The nonconductive nut 92 holds the electrode impeller disc 124 onto the end of
the drive shaft 86, as
described above. It also is understood, however, that the drive shaft 86
alternatively can be welded to the center
of the electrode disc 124 either by Tig or inertia welding. Where the
electrode disc 124 is welded to the shaft 86, -
the shaft 86 protrudes outside the volute plate 36 and is coupled with a
nonconductive shaft coupling member (not
shown) to the drive motor 28 in order to electrically decouple the motor 28
and the electrode impeller 30. (This
arrangement is described and illustrated in connection with the halogen
generator of Figure 6). However, because
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welding can deform the thin titanium plate 124, connection via the nut and
threaded shaft is preferred. By avoiding
welding, flatness of the electrode 30 can be maintained, the cost is reduced,
and serviceability is greatly simplified.
Further, with the threaded shaft design, the shaft 86 is cathodically
protected from corrosion as it is allowed to
contact the underside of the bipolar electrode plate 124 through the shoulder
88 on the shaft 86, but current is not
allowed to flow through the shaft to the cathodic side of the electrode plate
124 because of the nonconductive cap
nut 92.
As understood from Figure 2, the electrode plate 124 desirably carries a
plurality of small tabs 128 on the
side of the plate 124 which faces the cathode 96. The tabs 128 are spaced
apart from one another and are
positioned at various locations about the disc 124, both in terms of angular
and radial positions relative to the center
of the plate 124. The tabs 128, however, desirably lie generally tangential to
the rotation direction of the electrode
plate 124. This orientation of the tabs 124 minimizes the frontal area of the
tabs 128 as the tabs 128 rotate with
the plate 124 through the water, thereby minimizing the drag the tabs 128
produce on the electrode plate 124.
The tabs 124 help reduce scale buildup on the cathode 96, especially in
extremely hard water (e.g.,
hardness levels of 700 ppm and above). The tabs 128 contact large scale
buildup on the cathode plate 102 and
effectively chop the scale from the cathode plate 102. The sharp corners of
the tabs 128 provide excellent abrading
tools, and the tabs 128 are desirably left uncoated to enable oxide formation
thereon to increase the abrasive quality
of the tabs 128. And, in combination with the discontinuous cathode plate 102
illustrated in Figure 3, the tabs 128
are particularly useful in removing scale deposits from the fingers 106 of the
cathode plate 102.
It should be understood, however, that the electrode impeller 30 can
sufficiently descale the cathode 96
without the tabs 128 in water having normal to moderately high hardness levels
(i.e., 300 ppm to 700 ppm). The
addition of the tabs 128 thus improves the operation of the halogen generator
20 in extremely hard water.
As best seen in Figure 2a, the tabs 128 are spaced about the center of the
plate 124 at various distances
from the plate center. In the illustrated embodiment, the plate 124 includes
three tabs 128. The tabs 128 desirably
are integrally formed with the plate 124 and are punched out to extend
generally normal to the plane of the plate
124; however, it is contemplated that the tabs 128 could be separately formed
and attached to the plate 124 in
a known manner, such as, by spot welding, cementing, etc. The tabs 128 are
positioned away from the center of
the plate 124 at positions generally corresponding to a quarter of the radius,
a half of the radius, and the full radius
of the plate 124. Of course, other numbers and placements of the tabs 128 are
possible.
As understood from Figures 2 and 2a, the electrode impeller 30 includes a
plurality of curvilinear vanes 130
which are carried on and secured to the surface of the electrode plate 124
which faces the cathode 96. The vanes
130 are shaped and positioned so as to induce rotational movement of the water
within the central cavity 40 of
the volute 34. In the illustrated embodiment, the vanes 130 generally extend
from the center of the electrode plate
124 and extend toward the periphery of the plate 124 in a spiral fashion. Each
vane 130 includes a rounded inner
end 132 and a tapering outer end 134 which generally conforms to the outer
circular periphery of the bipolar
electrode plate 124. The vanes 130 have a generally rectilinear cross-sections
with flat surfaces facing the cathode
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96. The vanes 130 desirably are about 0.100 inches thick with sharp edges
formed between the sides and the flat
surfaces.
The impeller vanes 130 desirably are made from plastic or a resilient material
with 2096 glass-filled
polycarbonate for hardness. The vanes 130 alternatively may be made of a
metallic material, such as aluminum,
and coated with a nonconductive, wear-resistant coating.
As seen in Figure 2, the electrode plate 124 desirably includes a plurality of
apertures 136 located on a
side of the disc 124 that faces the cathode 96 to secure the vanes 130 to the
plate 124. The apertures 136 are
sized and positioned to receive pins 1388 on the underside of a plurality
curvilinear impeller vanes 130. In Figure
2, the vanes 130 are shown exploded to better illustrate the pins 138 and the
apertures 136 of the electrode plate
124.
The pins 138 may be press-fit into the apertures 136 andlor may be secured
within the aperture 136 by
partially deforming the ends of the pin 138 in a fashion similar to a rivet,
either by melting or peeving. The pins
138 also can be mechanically bonded, chemically bonded, or welded to a collar
positioned on the opposite side of
the electrode plate 124. It is also contemplated that the vanes 130 can be
bonded to the electrode plate 124, in
the alternative or in addition to attaching the pins 138 to the plate 124.
Haloeen Generator Assembly
With reference to Figure 1, the terminal post 58 of the cathode 96 is inserted
through the tubular segment
46 and the plug 56 to expose an outer end of the of the terminal post 58. A
conventional retainer ring or like
fastener (not shown) snaps onto the exposed end of the terminal post 58 to
couple the cathode with the volute 34.
The terminal post 58 may also be bonded to the plug 56 to secure the cathode
96 to the volute 34. A fluid seal
is provided within the cathode plug 56 with, for example. an 0-ring (not
shown).
In this position, the cathode plate 102 desirable rest flush against the inner
wall of the volute 34 with its
central hole 104 coaxially positioned relative to the opening of the inlet
port 46 (i.e., the tubular segment 50). The
disc 112 and spring 110 of the cathode 96 are housed within the tubular
segment 50 of the inlet port 46.
As understood from Figure 1, a conductor 140 leading from a negative terminal
142 of the controller 32
electrically connects to the outer end of the terminal post 58 to supply
electricity to the cathode plate 102. The
controller 32 and its operation will be discussed below.
The motor 28 is attached to the volute plate 36 by threading the elongated
bolts 94, which pass through
the motor body, into the threaded inserts 66 positioned on the outer side of
the volute plate 36. So attached, the
motor shaft 86 extends through the center hole 70 of the volute plate 36. A
conventional mechanical pump seal
74, such as the type available commercially from Cyclam of France, is seated
in the counterbore 72 on the inner
side of the volute plate 36. The seal 74 creates a fluid-tight seal between
the volute plate 36 and the motor shaft
86, while producing little friction or interference with the motor shaft 86 as
it rotates.
The anode plate 118 is seated on the volute plate 36 with its terminal post 84
extending through the
corresponding hole 82 in the volute plate 36. A conventional retainer ring or
like fastener (not shown) snaps onto
an exposed end of the terminal post 84 to secure the anode 98 to the volute
plate 36. The volute plate hole 82
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includes a fluid seal, such as an 0-ring (not shown), to prevent fluid from
exiting the cell through the hole 82. A
conductor 144 leading from a positive terminal 146 of the controller 32
electrically contacts the outer end of the
terminal post 84 to supply electricity to the anode plate 118.
. The bipolar electrode plate 124 is attached to the end of the shaft 86 by
the nonconductive nut 92.
Specifically, the plate 124 is inserted over a portion of the shaft 86 to rest
on the shoulder 88 of the stud 90 of
the shaft 86. The corresponding shapes of the aperture 126 in the electrode
plate 124 and the shaft stud 90 key
these components 86, 124 together to cause the electrode plate 124 to rotate
with the motor shaft 86. The
nonconductive nut 92 holds the electrode plate 124 on the end of the shaft 86.
In this manner, the shaft 86
generally is electrically isolated from the other components in the electrical
system. Fortunately, the motor armature
usually is already insulated.
The volute plate 36 is placed on the end of the volute 34 with the electrode
impeller 30 and anode 98
being inserted into the interior cavity of the volute 34. In this position,
the anode plate 118, electrode plate 124
and cathode plate 102 lie generally parallel to one another. Bolts (not
shown), passed through the corresponding
bolt holes 44, 80 in the lugs 42 of the volute 34 and in the outer flange 78
of the volute plate 36, cooperate with
, nuts (not shown) to hold the volute 34 and volute plate 36 together.
When assembled, the electrode plate 124 desirably is equally distanced from
the cathode plate 102 and
the anode plate 118. The gap spacings between the electrode plate 124 and the
anode plate 118 and between the
electrode plate 124 and the cathode plate 102 desirably is sufficient to
promote efficient electrolysis. That is, the
gap spacings are set so as to maximize the efficiency of the electrolytic Bell
24. In the illustrated embodiment, the
gap spacings range between about 0.15 and about 0.75 inches, and preferably
equal about 0.15 inches. The gap
spacings, of course, can be selected in order to suit a specific application.
The spacing between the outer surface of the vanes 130 on the rotary electrode
30 and the cathode plate
102 importantly also are tightly controlled, especially for operation in hard
water (i.e., water having a hardness of
greater than 700 ppm). In the illustrated embodiment, the outer surfaces of
the vanes 130 are spaced from the
cathode plate 102 by a distance which preferably ranges between about 0.03 and
about 0.1 inches, more preferably
ranges between about 0.03 and about 0.05 inches, and most preferably equals
about 0.03 inches. Although the
vanes 130 are placed in close proximity to the cathode plate 102, the vanes
130 do not contact the cathode 96
when the electrode plate 124 rotates.
The close spacing between the vanes 130 and the cathode plate 102 prevents
scale buildup on the cathode
96. As the bipolar electrode 30 rotates, the fluid velocity created at the
surface of the cathode plate 102 by the
vanes 130 substantially prevents scale from building up. Scale may temporarily
form on the surface of the cathode
plate 102, but the velocity of the water within the cell 24, and in
particular. between the vanes 130 and the surface
of the cathode plate 102, breaks the scale away from the plate surface 102.
Water flow through the cell 24, which
is produced by the vanes 130, carries the loose scale particles through the
outlet port 48 of the volute assembly
26 to flush the scale particles from the cell assembly 22. In addition, the
vanes 130 will mechanically knock-off
any scale deposits in excess of the gap spacing between the vanes 130 and the
cathode plate 102.
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From surface friction, the flat bottom surface of the bipolar electrode 30
also creates some rotational
velocity of the water between the bipolar electrode 30 and the anode 98. The
baffle 122, however, substantially
inhibits water from rotating close to the surface of the anode 98. This helps
prevent erosion of the anode 98. The
baffle 122 also inhibits the formation of substantial scale deposits on the
underside of the bipolar electrode 30 which
functions as a cathode. Like the vanes 130 on the opposite side of the rotary
electrode 30, the baffle 122 lies
close to the underside of the electrode 30. The close spacing between the
baffle 122 and the electrode plate 124
causes a rapid change of water velocity between the rotating electrode 30 and
the stationary baffle 122. In the
illustrated embodiment, the outer surface of the baffle 122 is spaced from the
rotary electrode 30 by a distance
which preferably ranges between about 0.03 and about 0.1 inches, more
preferably ranges between about 0.03 and
about 0.05 inches, and most preferably equals about 0.03 inches. Although the
baffle 122 is placed in close
proximity to the electrode plate 124, the baffle 122 does not contact the
electrode plate 124 as the plate rotates
124.
This small gap in which the water velocity changes from the rotational speed
of the electrode 30 to zero
velocity at the stationary baffle 122 greatly prevents the development of
scale buildup on the underside of the
electrode 30, much like the action between the vanes 130 and cathode plate
102. Scale may temporarily form on
the cathodic surface of the electrode 30, but the velocity of the water within
the cell 24, and in particular, between
the baffle 122 and the cathodic surface of the electrode 30, breaks the scale
away to be flushed out of the cell
assembly 22. In addition, scale buildup on the cathodic surface of the
electrode 30 in excess of the gap spacing
between the baffle 122 and the electrode plate 124 is knocked off by
mechanical contact with the baffle 122.
Operation of the Halonen Generator
When the controller 32 energizes the halogen generator 20, current flows
between the negative terminal
142 and positive terminal 144 of the controller 32. Electrical current flows
through the cathode 96, through the
electrolytic solution within the cell 24 and to the anodic surface of the
bipolar electrode 30. The electrical current
also flows through the bipolar electrode 30 to the cathodic surface of the
electrode 30 and through the electrolytic
solution within the cell 24 to the anode 98. Positive and negative charges are
induced on the cathodic and anodic
surfaces of the bipolar electrode 30, respectively. The bipolar electrode 30
thus acts as an anode on its surface
facing the stationary cathode 96 and acts as a cathode on the surface facing
the stationary anode 98. The
controller 32 desirably supplies about 2.4 amps of current to the anode 98 and
cathode 96, giving the anode and
cathode a current density of about 0.08 ampslcm2.
The electrical potential imposed between the electrodes of the cell 24
electrolytically causes the dilute halide
in the water to form pH neutral halogen, oxygen, and hydrogen, among other
compounds. For instance, when the
water contains a dilute solution of sodium bromide, the resultant electrolytic
process produces hypobromous acid and
hydroxide ions, hydrogen, as well as nascent oxygen. Hypobromous acid and
sodium hydroxide rapidly convert to
form bromide, a water sanitizing agent.
The controller 32 also activates the motor 28 of the halogen generator 20 when
the cell 24 is energized,
as discussed below. The motor 28 drives the electrode impeller 30 in a desired
direction to produce a flow of water
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through the cell assembly 22. The vanes 130 impart a rotational velocity
vector to the water as the vanes 130
rotate with the electrode impeller 30 through the water. Rotation of the water
thus creates a radially outward flow
which tends to force the water from the outlet 48 of the volute 34.
Water initially flows through the central bore 104 of the cathode 96,
perpendicularly toward the center of
the bipolar electrode 30. In the volute 34, water flows on both sides of the
bipolar electrode 30, but the rotation
of the water relative to the anode 98 is hindered by the presence of the
baffle 122.
As mentioned above, the relative water velocity between the lower surface, or
cathode side, of the bipolar
electrode 30 and the baffle 122 is relatively great, tending to inhibit scale
formation on the cathode side of the
bipolar electrode 30. Conversely, water flow adjacent the anode 98 is
minimized by the baffle 122 thus extending
the life of the anode 98 by reducing frictional erosion from water flow. The
baffle 122 is disposed at a slight radial
angle from the outer edge of the anode plate 118 toward the center and also
has a generally rectilinear cross-section
to present sharp edges for knocking excessive scale buildup off of the lower
surface of the bipolar electrode 30.
The controller 32 also desirably causes the motor 28 to periodically reverse
the rotational direction of the
impeller 30 during its operational cycle. Rapid reversals of the rotational
direction of the bipolar electrode 30 have
been found to causes scale deposits within the cell 24 to be quickly removed.
The rapid reversals in the bipolar
electrode's rotational direction create rapid water flow reversals relative to
the stationary cathode 96. These water
flow reversals also are present relative to the lower surface of the bipolar
electrode 30 by virtue of the stationary
baffle 122. Such flow reversals generate turbulence adjacent the cathodic
surfaces within the cell 24 to swirl and
knock off scale growth before it can affect the efficiency of the cell 24.
In an alternative mode of operation, the bipolar electrode 30 undergoes rapid
rotational direction reversals
several times at regular intervals as a maintenance step. For instance, the
controller 32 initiates a scale removal
sequence once every six hours of cell operation. During each scale removal
sequence, the controller 32 causes the
motor 28 to rotate the electrode impeller 30 in one direction for 15 seconds,
then reversed to rotate the electrode
impeller 30 in an opposite direction for another 15 seconds. This reversal is
repeated six times during the scale
removal sequence.
The controller 32 can alternatively initiate the scale removal sequence once
scale deposits reach an
undesirable level. This can be determined in a number of ways, the simplest of
which is by sampling of the cell
voltage which increases as a function of the resistance to current flow from
scale deposits. For instance, with a
cell 24 which operates efficiently below a predetermined voltage (e.g., 5
volts), the controller 32 initiates the scale
removal sequence when the voltage exceeds the predetermined value. The cell
cleansing process will be described
in more detail below in connection with the controller 32 and its operational
sequences.
The ability of the cathode plate 102 to move toward the rotary electrode 30
also enhances scale removal.
With reference to Figure 1, the spring 110 allows the cathode plate 102 to be
displaced in an axial direction within
the cell 24. The cathode plate 102 is mounted at an optimum spacing with
respect to the bipolar electrode 30 for
efficient electrolysis with the spring 110 in a relaxed, undeflected state. As
the pressure within the cell 24 changes,
the cathode plate 102 is displaced toward the electrode 30.
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For this purpose, the motor 28 drives the electrode impeller 30 at a high rate
of speed to generate a lower
pressure at its surface facing the cathode 96, thus urging the cathode plate
102 toward the bipolar electrode 30
and against the bias of the spring 110. Excessive scale buildup on the cathode
plate 102 will contact the vanes
130 or tabs 128, thus cleaning the cell 24 automatically. As the motor 28
slows down, the cathode plate 1O2
returns to the optimum spacing from the electrode 30 for efficient
electrolysis. This high speed cleaning cycle can
be easily accomplished with a minimum of electric circuitry by simply turning
off the power to the motor 28 (1 amp ,
10.5 VDC constant voltage) and switching the output with a relay from the cell
24 (2.4 amps constant current,
maximum 17 V) to the motor 28.
Other means for axially displacing the cathode 96 also are contemplated. For
instance, the cathode 96 may
be coupled to a solenoid (not shown) which positively displaces the cathode 96
upon receiving an actuation signal.
Thus, the cathode movement and associated scale removal are accomplished
independently of the speed of the motor
28. Alternatively, the solenoid may be replaced with a shape memory alloy
which expands or contracts in response
to electrical current changes. One example of such a material is Flexinol~'.
This embodiment would require much
less current than a conventional solenoid. In another embodiment, an external
spring can be used in place of the
internal spring 110 illustrated in Figure 2. An external spring (not shown)
may be provided between a nut attached
to the exposed end of the terminal post 58 and the volute inlet plug 56. And
in other embodiments, mechanical
displacement or magnetic attraction devices may be substituted for the
internal spring, all such devices enabling the
axial movement of the cathode plate 102.
Additional Halogen Generator Embodiments
Figure 6 illustrates a halogen generator 20a which is configured in accordance
with another preferred
embodiment of the present invention. Where appropriate, like reference
numerals with an "a" suffix have been used
to indicate like components between the two embodiments.
The generator 20a is in most respects similar to the generator 20 described
above and illustrated in Figure
1. The present generator 20a, however, incorporates a new volute design 34a, a
stationary cathode 96a and an
insulator coupling 150 between the motor shaft 86a and the electrode plate
124a. These differences in the present
halogen generator 20a will be discussed in detail below. A further description
of the balance components of the
present halogen generator 20a which are identical to those described above,
however, is not believed necessary for
an understanding of the present embodiment of the halogen generator.
With reference to Figure 6, the volute 34a includes a generally cup-shaped
housing 38a with a central cavity
40a having a cylindrical shape. The volute 34a also includes a plurality of
lugs 42a which extend outwardly from
the housing 38a. A bolt hole 44a passes through each lug 42a.
As understood from Figure 6, the volute 34a includes an inlet port 46a and an
outlet port 48a. The inlet
port 46a is configured to direct water flow into the central cavity 40a at the
center of the cavity 40a. The outlet
port 48a is positioned on the peripheral edge of the housing 38a, generally
tangentially to the cylindrical central
cavity 40a of the housing 28a. This position of the outlet port 48a encourages
the conversion of water velocity
to pressure, as known in the art.
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In the illustrated embodiment, the volute water inlet 46a includes a tubular
segment 50a which extends
axially from the center of the volute 34a. A water inlet conduit (not shown),
which communicates with the water
feature (e.g., spa circulation system), is attached to the tubular segment 50a
to supply water to cell assembly 22a.
The tubular segment 50a directs the flow of water into the cylindrically
shaped central cavity 40a at the center of
the cavity 40a and in a direction along the axis of the cavity 40a.
The volute 34a also includes an access hole 152 in the housing 38a at a
position proximate to the side
wall of the central cavity 40a. The hole 152 is sized to receive a terminal
post 58a of the cathode plate 102a,
as described below. An 0-ring seal, or other similar expedient, is provided
within the access hole 152 to seal around
the terminal post 58a.
The cathode 96a includes a disc-shaped plate 102a having a central water inlet
bore 104a, and the offset
terminal post 58a. The post 58a extends through an access port 152 of the
present volute 34a. By offsetting the
terminal post 52a, the central inlet port 46a may be enlarged in comparison to
the halogen generator of Figure 1
which has a central terminal post 58. The enlarged port size helps prevent
excess scale from plugging the port 46a
and restricting flow.
The cathode plate 102a is sized and configured in accordance with description
given in connection with the
above embodiment. The cathode plate 102a also is constructed of 316L stainless
steel or any other suitable metal,
such as, for example, copper or titanium.
In the present halogen generator 20a, the cathode 96a is stationary, both in
the rotational and axial
directions. Although it has been found that axially displacing the cathode
with respect to the bipolar electrode
enhances scale removal, it has also been discovered that rapid reversals of
the bipolar electrode can serve to rapidly
clean the cell. The present embodiment thus illustrates that these features
can be used either together or apart.
The bipolar electrode 30a is similar to the bipolar electrode 30 described
above, with the absence of the
tabs 128 and the presence of a permanently attached shaft 154. The drive shaft
154 may be welded to the
titanium electrode 30, as shown in Figure 6. In the welded embodiment, a shaft
154, which is about 0.125 inches
or larger in diameter, with about 0.25 inches preferred, can be welded. to the
center of the electrode 30 either by
Tig welding or inertia welding before the electrode 30 is coated. The shaft
154 then protrudes outside the volute
plate 36a and is coupled with the~nonconductive shaft coupling member 150 to
the drive motor 28.
There are several different configurations of rotary electrodes 30a within the
cell 24a, as will be explained
in detail below, all including a downwardly depending shaft 154 surrounded by
a bearing 168 and pump seal 74a
disposed within the bore 70a of the volute plate 36a. The rotating electrode
30a can of course be driven by
alternative means obviating the need for a rotational seal, such as by an
external rotating magnet drive.
The anode 98a also is similar to the one described above with the exception of
a removable baffle 122a
in place of an integral baffle 122. The baffle 122a is provided with a pair of
pins 156 which fit within apertures
158 in the electrode plate 118a.
As seen in Figure 6, a drive motor 28 is attached to the volute plate 36a via
an extension bracket 160
and an extension tube 162, these components being cemented together or
detachably coupled in a conventional
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manner. The drive motor 28 includes a pair of anti-rotation pins 164 which
mate with apertures 166 in the
extension bracket 160. The drive shaft 86a of the motor 28a is sized to fit in
one end of a shaft coupling member
150, which has an opposite end that is sized to receive the downwardly
depending shaft 154 on the rotary electrode
30a.
The present halogen generator 20a is assembled in substantially the same way
as the halogen generator
20 of Figure 1. The present halogen generator 20a also operates in a
substantially identical manner to that of the .
halogen generator 20 of Figure 1. The only difference in the operation of the
two halogen generators is that the
present halogen generator 20a does not include a high speed cleaning cycle
where the gap spacing between the
cathode 96a and the rotary electrode 30a is decreased. Otherwise, the
operations are identical, and further
description of the assembly and the operation is not believed necessary for an
understanding of the present halogen
generator ZOa.
Figures 7 and 8 illustrate additional preferred embodiments of electrolytic
cell configurations which can be
used with the halogen generator of Figure 6. The embodiments illustrated by
these figures, however, are otherwise
identical to the halogen generator described above. Accordingly, the foregoing
description of the halogen generator
should be understood as applying equally to the embodiments of Figures 7 and
8, unless specified to the contrary.
Figure 7 illustrates a electrolytic cell configuration in which a rotating
anode 170 is positioned between two
stationary cathodes 172, 174. Where appropriate, like reference numerals with
a "b" suffix have been used to
indicate like components between the two embodiments of the electrolytic cell.
The cathodes 172, 174 include disc-shaped plates 102b and electrode terminal
posts 58b, 175, respectively.
The upper cathode 172 includes a central bore 104b for passage of input water
flow. The lower cathode includes
a central bore 176 through which the rotating shaft 154b of the anode 170
extends.
The rotating anode 170 includes a disc-shaped plate 178 which carries a
plurality of vanes 130b. The
vanes 130b are mounted on both sides of the anode 170 in order to circulate
water flow adjacent the underside
of the upper cathode 172 and the upper surface of the lower cathode 174. In
this manner, scaling is greatly
reduced on the cathode surfaces 102b in a manner similar to that described
above. Furthermore, water flow directly
adjacent the opposite surfaces of the rotating anode 170 is minimizes due to
the upstanding vanes 130b, thus
reducing erosion of the anode 170.
The anode plate 178 also includes a plurality of tabs 128b to promote scale
removal on the opposing
cathode surfaces 102b. Although Figure 7 illustrates the tabs 128b extending
only from the top side of the anode
plate 178, it should be understood that the tabs 128 preferably extend from
both sides of the anode plate 178.
The anode 170 and the two cathodes 172, 174 are arranged within the cell 24b
assembly in a manner
identical to that described above in connection with the bipolar electrolytic
cell configuration of Figure 6. That is,
the cathodes 172, 174 are rigidly affixed to the volute 34b and volute plate
36b within the central cavity 40b. The
rotary anode 170 is supported and driven by the drive shaft 154b. The anode
170is placed between within the
cathode plates 102b at the desired gap spacings recited above.
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As understood from Figure 7, the anode 170 is energized via a conventional
brush connection or through
the use of a spring-loaded conductor 180. The conductor 180 is mounted within
a housing 182 and is biased by
a spring 184 against the shaft 154b. The housing 182 is preferably affixed
with respect to the volute plate 36a.
The conductor 180 is electrically connected with the positive terminal 146b of
the controller 32b. A portion of the
shaft 154b may be made of copper and inertia welded to the titanium shaft to
provide electrical contact.
Figure 8 illustrates an additional electrolytic cell configuration for use
with the halogen generator illustrated
in Figure 6. Where appropriate, like reference numerals with a "c" suffix have
been used to indicate like components
between the two embodiments of the electrolytic cell.
In this embodiment, a rotating anode 170c faces a single stationary cathode
172c within the cell assembly
22c. The cathode 172c comprises a disc-shaped plate 102c and an upstanding
electrode terminal post 58c which
extends through the volute 34a. The cathode terminal post 58c is electrically
connected with the negative terminal
142c of the controller 32c. The cathode plate 102c also includes a central
bore 104c for passage of water into
the electrolytic cell 24c.
The rotating anode 170c includes a disc-shaped plate 178c which carries a
plurality of vanes 130c attached
to the top surface of the plate 178c. The vanes 130c are shaped to generate
rotational water flow adjacent the
underside of the cathode plate 102c. In this manner, scaling is greatly
reduced on the lower cathode surface 102c,
as described above. Furthermore, water flow directly adjacent the opposite
surface of the rotating anode 170c is
minimizes due to the upstanding vanes 130c, thereby reducing erosion of the
anode 170c.
The anode plate 178c also includes a plurality of tabs 128c which extend from
the anode plate 178c
toward the cathode plate 102c. The tabs 128c enhances scale removal as
previously described.
A shaft 154c depending downward from the anode 170c makes electrical
connection with a conductor
180c. The conductor 180c is mounted within a housing 182c and is biased by
spring 184c against the shaft 154c.
The conductor 180c is electrically connected to the positive terminal 146c of
the controller 32c. The housing 182c
is preferably affixed relative to the volute plate 36a. The biased contact
between the conductor 180c and the shaft
154c electrically connects the shaft 154c to the positive terminal 146c of the
controller 32c while allowing the shaft
154c to rotate.
It also is contemplated that the present halogen generator may be modified to
utilize a nonconducting
rotating impeller (not illustrated) in place of the bipolar electrode 30 shown
in Figure 1. In most respects. the
impeller is similar to the electrode of the halogen generator of Figure 1,
except that a plurality of apertures are
formed through the disc shaped body. The apertures allow electrical current to
flow via the conductive fluid from
the anode to the cathode. The nonconducting impeller thus provides all of the
advantageous scale cleaning and
water circulating benefits of the bipolar electrode described previously.
Indeed, a conventional pump may be retrofit
to operate as the cell with the addition of two electrodes and a slight
modification of the impeller; namely, apertures
would be formed in the impeller. Such a retrofit cell could function with or
without polarity reversal due to the
beneficial scale removal characteristics of the impeller vanes.
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Application of Halogen Generator to Conventional Spa System
The present halogen generator 20 can be incorporated into a spa system in
several ways. Figures 9a
through 9d schematically illustrate several possible layouts of the halogen
generator 20 in a conventional spa system.
Figures 9a and 9c illustrate the halogen generator 20 incorporated (i.e.,
retrofitted) into the conventional water
circulation system of the spa system. Figure 9c illustrates the halogen
generator 20 disposed within its own
dedicated line.
In the in-line configuration illustrated in Figure 9a, the halogen generator
20, including the cell 24 and motor
28, is placed in series with a circulation or spa pump 186. The conventional
pump 186 may be a small 24 hour
pump to recirculate the water for heating and filtering purposes. The
generator 24 thus may be operated 24 hours
a day. The spa system may also employ one or more booster pumps which drive
the spa jets or employ a two-speed
circulation pump. In the latter case, the circulation pump, set on a low
speed, filters and heats the spa water during
a preset period (e.g., four hours per day). When the spa is in use, the
circulation pump is set to a high speed to
drive the spa jets. Other systems may employ two or more two speed pumps which
are placed in series. For
simplicity, Figures 9a and 9b model these various convention pump systems as a
single block.
With the in-line configurations illustrated in Figure 9a, the halogen
generator 20 is generally run only with
the circulation pump 186 is on, although in some cases only the motor 28 of
the generator 30 may be energized
to produce a water flow through the cell assembly 24. In this regard, the
generator 20 may even replace the
circulation pump and function as both the conventional circulation device with
the cell de-energized, and periodically
as a halogen generator with the cell energized.
Figures 10 and 11 illustrate two alternative arrangements for coupling the
halogen generator 20 with a
conventional water circulation system, downstream of the spa pump 186. Figure
10 illustrates an arrangement
where the halogen generator 20 is positioned in parallel to a spa heater 190,
and Figure 11 illustrates an
arrangement where the halogen generator 20 is positioned in series with the
spa heater 190.
In Figures 10 and 11, the cell 24 is shown installed in a bypass line 192
fluidly connected in parallel with
the main circulation line 194 between the spa pump 186 and the spa body or
container 188. A return line 196
fluidicly connects the spa body 188 to the spa pump 186. The heater 190 is
typically positioned in series with the
main circulation line 194. The bypass line 192 includes an inlet opening 198
and an outlet opening 200 which
fluidicly connect the bypass line 192 with the main circulation line 194.
Thus, the action of the impeller 30 within
the cell 24 draws water through the inlet opening 198 and through the central
water inlet 46 of the halogen
generator 20. Water is discharged through the water outlet 48 of the halogen
generator 20 to travel along the
bypass line 192 and exit the bypass line 192 at the outlet opening 200. In
Figure 10 the outlet opening 200
connects to the main circulation line 194 at a position downstream of the
heater 190. In Figure 11, the outlet
opening 200 connects to the main circulation line 194 at a location upstream
of the heater 190.
In both of the system configurations illustrated by Figures 10 and 11, a
bypass check valve 202 is installed
in the circulation line 194 between the inlet opening 198 and the outlet
opening 200. This bypass check valve 202
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allows the call to operate when the pump 186 drives the spa jets, as well as
prevents water from flowing back
toward the spa pump 186 fi.e., "short circuiting" the plumbing system).
When the spa circulation system is operated, the spa pump 186 and the halogen
generator 20 together
. create a water flow through inlet opening 198 and into the inlet port 46 of
the halogen generator 20. When the
check valve 202 is closed, all of the water in the circulation system flows
through the halogen generator 20. But
when the pressure at the inlet opening 198 to the bypass line 192 reaches a
preset level, the check valve 202
openings to allow a portion of the water flow through the circulation system
to bypass the halogen generator 20
and flaw directly into the main circulation line 194. For instance, when the
spa pump 186 is at a high speed, water
flows through the bypass check valve 202 and through the heater 190 in
parallel to water flowing through the
bypass line 192.
When the spa circulation system is not operated li.e., the spa pump 186 is not
activated), the bypass check
valve 202 remains closed, preventing flow along the main circulation line 194
in the direction from the outlet opening
200 to the inlet opening 198. All of the water flow through the circulation
system flows through the halogen
generator 20. which generates the water flow.
Figures 12a and 12b illustrate a preferred embodiment of the present in-line
bypass check valve 202. In
the illustrated embodiment, the check valve 202 is housed within a standard T-
fitting 204. As seen in Figures 12a
and 12b, the check valve 202 comprises a piston 206 made of ABS or other
suitable polymer, a rubber gasket 208
and a retainer 210 made of ABS or other suitably polymer. The rubber gasket
208 is preferably constructed of a
suitable elastomer such as neoprene or EPDM. The piston 206, rubber gasket
208, and retainer 210 can be
cemented or bolted together to retain the gasket 210 and seal it against a
bypass body 212 when in the closed
state (i.e., when the spa pump 186 is off andlor operated at a low speed). A
piston shaft 214 extends through a
matching hole 216 in the bypass body 212 and a spring 218 slides over the
shaft 214 and is secured thereon by
a nut 220 or by solvent cementing. The spring 218 biases the bypass check
valve piston 206 against the gasket
208 (i.e., biases the check valve 202 closed) to prevent water flow through
the opening in the bypass body 210,
but allows the piston 206 to open fully at pressures greater than a preset
limit. In the illustrated embodiment, the
check valve 202 opens at pressures equal to or above about 0.5 psi. Of course,
when the valve 202 is closed, the
bypass check valve 202 prevents backflow in the direction from the outlet
opening 200 to the inlet opening 198
of the bypass line 192.
A port nozzle 222, typically a 3l8 inch schedule 80 PVC nipple, at the end of
a tubular member 224 is
solvent cemented into an aperture 226 in the bypass body 210. Corresponding
apertures are provided in the piston
206, gasket 208 and retainer 210. The bypass body 210, in turn, is glued into
an outlet port 228 on the tee fitting
204 leading to the heater 190. Although not illustrated, the bypass body 210
also may be solvent cemented into
a wall fitting insert for direct coupling to the spa body 188.
The bypass body 210 and piston assembly reside in the tee fitting 204 at a
point downstream from an spa
pump inlet port 230 in the tee fitting 204. This allows it to both restrict
flow while the spa pump 186 is operating
and to prevent flow between the bypass line outlet 200 and inlet opening 198
(see Figures 10 and 11). When the
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spa pump 186 is off, the halogen generator draws water from the inlet side of
the piston 206 and accelerates it
through the port nozzle 222 where it continues through the piston assembly
while the valve 202 is closed.
In the configuration illustrated in Figure 9b, the generator 20 is positioned
downstream of the spa pump
186. That is, water circulates from a spa body 188 through the pump 186, a
portion through the cell 24, and back
through the spa pump 186 and into the spa body 188. In this configuration the
spa pump 186 enhances the water
flow through the cell 24 and typically operates about four to six hours a day.
Nevertheless, the rotating electrode
30 within the cell 24 is actuated when a potential is applied to the cell 24
to avoid buildup of entrapped gases (e.g.,
hydrogen and oxygenl. In this configuration the cell 24 operates only with the
circulation system.
Figure 9c illustrates another "in-fine" configuration of the halogen generator
20 in which the generator is
installed downstream of a spa pump 186 which operates less than 24 hours a day
(typically four to six hours a dayl.
A conventional check valve is installed after a heater and performs both the
function of a bypass valve and a check
valve. The inlet and outlet of the cell 24 are tapped into the inlet and
outlet of the check valve, respectively.
This configuration is used where the halogen generator 20 is intended to be
operated 24 hours a day.
Thus, when the spa pump 186 is on, the check valve is open and water flows
both through the check valve and
through the cell 24. When the spa pump 186 is off, the check valve is closed
and the water flow in the circulation
system flows through the cell 24.
Common to the in-line configurations of Figures 9a, 9b, and 9c, installing the
halogen generator 20 directly
in the circulation line allows for easy retrofit and eliminates the need for a
separate wall fitting in the spa body 188.
A separate wall fitting for the spa body 188 is not needed. And with the
layouts illustrated in Figures 9a and 9b,
the spa halogen generator 20 also can be plumbed in series with or in parallel
to the spa heater 190.
Figure 9d illustrates a spa system configuration in which the spa halogen
generator 20 is placed in a
separate flow line 234 in communication with the spa body 188. The halogen
generator 20 may be mounted close
to the side of the spa body 188, as will be described below, or may be
remotely located and connected via a length
of tubing or hose. Remotely locating cell 24 and motor 28 may simplify
installation and maintenance.
With reference to Figures 13a-c and 14, the halogen generator 20 can be
incorporated into a single wall
fitting assembly which inserts into a hole in the spa body 188 normally used
for a spa jet. This approach allows
operation completely independent from the circulation or jet pump line and
simplifies installation and service. The
inlet and outlet for the halogen generator 20 can be at the same level, or the
inlet can be positioned at a higher
elevation than the outlet. In either case, if a fault occurs in the motor 28,
the halogen generator 20 design will
allow gases to harmlessly vent to the atmosphere.
As seen in Figure 13a, a wall mount fitting assembly 239 includes a coaxial
manifold 240. The coaxial
manifold 240 is connected to the generator 20 and comprises a cylindrical
housing 242 within which fluid flow
communicates between a first tube 244 and an inner coaxial lumen 246, and
between a second tube 248 and an
outer coaxial space 250. The first and second tubes 244, 248 extend from the
housing 242 away from the spa
body 188 toward the halogen generator 20 (not illustrated in Figure 13a). One
of the tubes 244, 248 functions as
a water inlet to the generator 20 and the other as an outlet to the spa 188.
Likewise, water flows in opposite
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directions through the coaxial lumens 246, 250, one lumen functioning as an
inlet to the generator 20 and one as
an outlet.
As discussed below in connection with the control system 32 used with the
present halogen generator 20,
an oxidation-reduction potential (ORP) sensor 252 may be used to activate the
halogen generator 20. For this
purpose, Figure 13a illustrates one possible installation location of the ORP
sensor 252 in which the sensor 252
- extends into a sensor port 254 in the housing 242 at a perpendicular angle
with respect to the axis of the housing
242. In this position the ORP sensor leads can be oriented in parallel to the
water flow internal to the housing 242.
Although not illustrated, the sensor leads commonly comprise a pair of short
wires extending in parallel from
the sensor 242 and between which the fluid electrical potential can be
measured. Orienting the leads in parallel with
the water flow reduces entrapment of scale and other debris by the sensor
leads. The ORP sensor 252 provides
one method of monitoring the halogen concentration in the spa 188 for use in
controlling the length and timing of
the cell operation. Accordingly, the sensor 252 is preferably installed in a
port in communication with the suction
line from the spa to the cell. Alternatively, the sensor 252 may be installed
in a position in which the leads extend
into the volute 34 at a slight angle with the leads pointing in the same
direction as the water velocity vector within
the cell assembly 22. This will serve to reduce debris entrapment and also
enhance the cleaning of the sensor leads
as they will be subject to a high water velocity proximate the rotating
impeller electrode 30.
The coaxial manifold 240 includes an outer male threaded region 256 which
engages a coupling nut 258.
The nut 258 couples the coaxial manifold 240 to a tubular portion 260 of a
wall fitting 241 having mating external
threads and forming an inlet to the spa body 188. The nut 258 thus secures the
coaxial manifold 240 to the wall
fitting 241. The coaxial manifold 240 fits within the tubular portion 260 and
is sealed therein by virtue of an 0-ring
(not shown) seated within a groove 262.
A circular flange 264 formed on the spa end of the wall fitting 241 sits flush
against the inner surface
of the spa body 188 with a gasket 266 therebetween. A spa end of a tubular
threaded element 267 is secured
to the flange 264 creating an annular space therebetween. A tightening nut 268
mates with the threaded element
267 on the outer surface of the spa body 188 to secure the assembly to the
spa.
An indicator ring 270 may be provided in the annular space between the wall
fitting tubular portion 260
and tubular threaded element 267. The indicator ring 270 is provided with a
plurality of LED indicators and is in
electrical communication with the controller 32. The flange 264 is preferably
translucent so as to expose the
indicator LEDs to the inside of the spa body 188. The condition of the
generator 20 determines which indicator LED
is activated thus providing a convenient monitoring system without having to
visually inspect the generator 20, as
described below.
In one particular embodiment, a red, an amber, and three green LED indicators
are provided around the
indicator ring 270. The three green LED indicators may be illuminated
constantly when the spa is sanitary and may
be sequentially illuminated when the generator 20 is in operation. The amber
LED indicator may be illuminated
constantly when the halogen level is high, and blink when the halogen level is
low. Finally, the red LED indicator
can blink when there is a fault in the halogen generator 20. For an
interesting visual enhancement, the indicator
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ring may be installed within a spa hydrotherapy jet outlet. Alternatively, the
wall fitting may be designed as a light
pipe with a single color LED indicator provided to warn of a fault in the
system. Moreover, the provision of the LED
indicator ring 270 is not limited to operation only in conjunction with the
halogen generator 20 and may be installed
as a stand-alone unit as an indicator of spa water quality for use with a
conventional control system. ,
Figures 13b and 13c illustrate a simplified wall fitting assembly 239d for
attaching the halogen generator
20 to the spa body 188. Where appropriate, like reference numerals with a "d"
suffix have been used to indicate
like components between the two embodiments of the wall mount fittings
illustrated in Figure 13a and 13b.
The present wall mount fitting assembly 239d includes a coaxial manifold 240d
which is connected to the
generator 20 (not illustrated in Figure 13b) and a wall mount fitting 241d
which is connected to the spa body 188.
The coaxial manifold 240d comprises a cylindrical housing 2424 within which
fluid flow communicates between a
first tube 244d and an outer tube 250d, and between a second tube 248d and an
inner coaxial tube 246d. The
first and second tubes 244d, 248d extend from the housing 244d away from the
spa body 188 and toward the
halogen generator 20 (not illustrated in Figure 13b). The first tube 244d
functions as a water inlet to the generator
and the second tube 248d functions as an outlet from the generator 20 to the
spa 188. Likewise, water flows
15 in opposite directions through the coaxial lumens of the coaxial tubes
246d, 250d. The lumen of the outer tube
250d functions as an inlet to the generator 20 and the lumen of the inner tube
2464 functioning as an outlet from
the generator 20.
An oxidation-reduction potential (ORP) sensor 2524 may be integrated into the
coaxial manifold 240d.
Figure 13b illustrates one possible installation location of the ORP sensor
252d in which the sensor 252d extends
20 into a sensor port 254d in the housing 242d. The port 254d is positioned
such that the sensor 252d extends into
the housing 242d in a direction which is generally normal to the longitudinal
axis of the housing 242d. In this
position, the leads of the ORP sensor 252d can be oriented in parallel to the
water flow internal to the housing
242d.
As discussed above, the sensor leads may comprise short wires which extend
parallel to each other from
the sensor 252d and between which the water electrical potential can be
measured. The port 254d, in which the
sensor 252d is installed, desirably is in communication with the suction line
from the spa body 188 to the halogen
generator 20. The sensor 252d alternatively can be installed in a position in
which the sensor leads extend into the
volute 34 at a slight angle with the leads pointing in the same direction as
the water velocity vector within the cell
assembly 22. This will serve to reduce debris entrapment and also enhance the
cleaning of the sensor leads as they
will be subject to high water velocities proximal to the rotating impeller
electrode 30.
As best seen in Figure 13b, the coaxial manifold 2404 includes a flange 255
which circumscribes the outer
tube 250d. The flange 255 includes an annular groove 257 formed in its front
facing surface. The groove 257
forms an 0-ring seat on the front face of the flange 255 about the lumen of
the outer tube 250d. The flange 255 -
has a diameter larger than the outer tube 250d but smaller than the housing
242d.
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The coaxial manifold 242d also includes a slidable collar 259 which is
captured between the housing 2424
and the flange 255. The collar 259 secures the coaxial manifold 2404 to the
wall fitting 241 d, as described below.
The collar 259 has a tubular shape with a closed end proximate to the housing
242d. The closed end
includes a central hole which receives the outer tube 2504. In this manner, as
understood from Figure 13b, the inner
and outer tubes 246d, 250d pass through the collar 259.
The collar 259 includes an inner thread on an inner surface of the collar 259
which slides over the flange
255 and outer tube 250d. The inner thread is configured to cooperate with the
external threads of the wall fitting
2414 mounted to the side of the spa body 188, as described below.
The collar 259 moves from a first position in which its front inner thread
(i.e., the thread closest to the
spa body 1881 lies behind the front face of the flange 255 to a second
position in which its front inner thread lies
forward of the front face of the flange 255. In this manner, the collar 259
moves from a position in which the
flange 255 abut the rear end of the wall mount fitting 241 d without
interference from the collar 259, to a position
in which the collar 259 engages the external threads of the wall mount fitting
241 d to compress the 0-ring between
the flange 255 and the rear end of the fitting 241 d and to secure the coaxial
manifold 240 to the fitting 241 d.
The wall fitting 241d is positioned on the inside of the spa body 188 and is
adapted to extend through
a hole 261 in the body 188. The wall fitting 241d includes a circular flange
264d formed on the spa end of the
wall fitting 241d to sit flush against the inner surface of the spa body 188
with the gasket 266d interposed
therebetween. The circular flange 264d includes a center hole 263 which is
sized to receive the end of the inner
tube 246d. As seen in Figure 13c, when assembled, the end of the inner tube
246d extends through the central
hole 263 and lies generally flush with the face of the circular flange 264d.
The circular flange 264d also includes
a plurality of smaller orifices 265 which are positioned about the larger
center hole 263. The smaller orifices 265
extend through the flange 264d and communicate with an inner space defined by
a tubular shank 267d.
As understood from Figure 13b, the tubular shank 2674 has an outer diameter
sized to fit through the hole
261 in the spa body 188. The shank 267d carries an external thread which
cooperates with the internal threads
on the collar 259 of the coaxial manifold 240d. The external threads on the
tubular shank 267d also cooperate with
a tightening nut 268d which is used to secure the wall fitting 241 d to the
spa wall. With the externally threaded
shank 267d of the wall fitting 241 d extending through the hole 261 in the spa
body 188, the nut 268d screws onto
the outer end of the shank 2674. The nut 2684 is tightened until the flange
2644 firmly compresses the gasket
266 against the wall of the spa body 188. Before the coaxial manifold 240d is
coupled to the wall fitting 241 d,
an end cap (not shown) also may be screwed onto the threaded shank 2674 to
prevent water flow through the wall
fitting 241 d when not in use.
Figure 13c illustrates the wall fitting assembly 2394 attached to the spa body
188. To attach the coaxial
manifold 240d to the installed wall fitting 241d, the collar 259 is threaded
onto the end of the threaded shank 267d
outside the spa body 188. The 0-ring on the flange 255 of the coaxial manifold
240d is compressed against an
annular rear facing surface on the end of the threaded shank 2674. As the
collar 259 is tightened onto the shank
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267d, the 0-ring is compressed to form a seal between the coaxial manifold
240d and the threaded shank 2674 of
the wall fitting 241 d.
With the coaxial manifold 240d attached to the wall fitting 241 d, the inner
tube 246d of the manifold 2404
extends through the threaded shank 267d and through the large center hole 263
in the circular flange 264d. As .
discussed above, the inner tube 246d desirably extends to a point flush with
the front surface of the circular flange
264d. The outer tube 250d desirably has a size which generally corresponds
with the size of the threaded shank
267d such that the inner space within the tubular threaded shank 2674
communicates with the lumen of the outer
tube 250d.
As understood from Figure 13c, when the wall mount fitting assembly 239d is
assembled, water, which
is drawn through the small holes 265 in the circular flange 264d of the wall
fitting 241, flows through the inner
space of the threaded shank 267d, through the lumen of the outer tube 250d and
through the suction tube 244d
into the spa generator 20. The small holes 265 of the circular flange 264d
function as a filter to prevent large
particles or debris from being drawn into the spa generator 20. The outlet of
the spa generator 20 communicates
with the outlet tube 248d which in turn communicates with the inner tube 246d.
Thus, the water flow from the
generator 20 is returned to the spa body through the inner tube 2464
positioned at the center of the circular flange
264d of the wall fitting 241.
Figure 14 illustrates another simplified fitting assembly for attaching the
halogen generator 20 to the spa
body 188. The assembly includes a housing 272 having parallel through bores
for receiving a pair of tubular conduits
274, 276 representing an inlet and an outlet, respectively, from the halogen
generator 20. The housing 272 includes
a cylindrical portion 278 having a diameter sized to closely fit within a
threaded tubular portion 280 of a wall fitting
282. A flange 284 on the housing 272 abuts a terminal lip of the tubular
portion 280. Preferably, the cylindrical
portion 278 is solvent bonded within the tubular portion 280. The diameters of
the flange 284 of the housing 272
and of the tubular portion 280 of the wall fitting 282 are sized to fit
through an aperture in the spa body 188.
A retaining nut 286 engages the tubular portion 280 to retain the wall fitting
282 on the spa body 188.
Tightening nut 286 compresses a gasket 288 between a wall fitting flange 290
and the spa body 188 to provide
a fluid seal therebetween. A plug 292 fits within an inner recess 294 in the
wall fitting 282. The plug 292 may
be used when disassembling the halogen generator 20 from outside the spa body
188 for repair, or otherwise, to
prevent water from escaping the spa through the wall fitting 282. The plug 292
has smooth sides and snugly fits
into the recess 294 so as to easily be expelled therefrom in the event of an
unsafe buildup of entrained gasses
within the halogen generator 20, such as might happen if the plug 292 is
inadvertently left installed with the cell
24 in operation. '
Scale Tran
With reference to Figure 15, a scale trap 296 can be used with the present spa
halogen generator 20.
In the illustrated embodiment. the scale trap 296 is attached to the outlet
conduit 276 from the halogen generator
20 which passes directly through the spa body 188.
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.27.
The scale trap 296 comprises an open top container 298 having an inlet 300
from the conduit 276
approximately half way up from the bottom of the container 298. Water from the
halogen generator 20 is
discharged through the inlet port 300 and into the scale trap 296. The scale
trap 296 desirably is mounted beneath
the water level of the spa so that the water discharged from the halogen
generator 20 enters and mixes with the
existing water in the spa. Particles of scale discharged from the halogen
generator 20 generally fall under gravity
to the bottom of the trap 296. The spa owner must occasionally check and empty
the trap 296 to avoid clogging
the trap inlet port 300. The rudimentary configuration of the scale trap 296
is shown as an example only and other
embodiments which provide automatic scale removal, for instance, also are
possible.
Controller and Electrical Supply System
With reference to Figures 1 and 16a, the controller 32 includes a positive
terminal 146 and a negative
terminal 142 which are connected to the anode 98 and the cathode 96,
respectively. The controller 32 also
desirably exhibits one or more indicator lights 302 for displaying the
operating condition of the halogen generator
20, as described below. For instance, the indicator lights 302 light if the
cell 24 is energized.
As understood from the block diagram of Figure 16a, the controller 32 derives
power from an external
source through a transformer 304, which is shown as a separate element from
the controller 32 but is preferably
formed integrally therewith. The controller 32 also supplies energy to the
drive motor 28 via power leads 306.
Figure 16a also illustrates the electrical connection between ORP sensor 252
with the controller 32. The
controller 32 senses the ionic potential, and thus the halogen concentration,
of the water within the spa body via
the oxidation-reduction potential (ORP) sensor 252. The control circuit must
determine when the halogen
concentration falls below a prescribed value to initiate the cell operation.
If the controller 32 detects a voltage
below this prescribed value, it will initiate the cell output which will
continue until the halogen concentration
increases to a desirable level. This operational cycle is shown and described
with reference to Figure 17b.
Alternatively, a timed output cell cycle may be utilized, this cycle being
described with reference to Figure 17a.
Figure 16b illustrates a control system for use with an AC motor 28. In this
embodiment, a simple onloff
control 308, or optoisolated triac is included in the power supply from the
controller 32 to the motor 28.
The controller 32 can be completely housed within a polymeric enclosure with a
terminal strip to which the
various IIO lines can be connected. The secondary of an external class II
transformer is also connected to this strip.
The current is phase controlled to minimize heat generation within the
enclosure and supply constant current output
to both the DC motor 28 and the cell 24. With this arrangement, the current to
the motor 28 can be varied via
programming for different installations, i.e., an independent wall fitting
installation versus one with the pump cell 24
in parallel with the spa circulation system. Alternatively, the power to the
pump can be supplied from the primary
of the class II transformer and controlled via optoisolators.
Controller Timed Operation of Spa Halogen Generator
Figure 17a depicts a flowchart which illustrates the general operation of the
controller 32 which actuates
the halogen general 20 at regular intervals throughout the day. Initially, as
represented in operation block 310, the
user or manufacturer of the generator 20 sets the duty cycle time. The duty
cycle time is repeated throughout a
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.28.
24-hour period and the cell 24 is instructed to remain in operation for a
fraction of each duty cycle. The user also
sets the cell cycle time, as represented in operation block 312, by turning a
time dial (not illustrated) or likewise
adjusting a timer which may be located on the controller 32. The time dial
indicates a range of time increments or
percentages of a maximum time. For instance, the time dial may be marked with
a range of 1 to 20 minutes. The ,
setting of the time dial fixes the amount of time the cell 24 remains on
during each duty cycle. If the duty cycle
is set to 20 minutes, and the time dial is set to 20 minutes, then the cell 24
will remain on continuously. On the
other hand, if the time dial is set to 10 minutes, the cell 24 will turn on at
the beginning of each duty cycle but
will remain on for only half the duty cycle, thus resulting in an output of
the cell 24 which is 50~ of it potential.
The controller 32 desirably displays the cell cycle time set by the user, as
represented in operation block 314, either
directly on the dial or an a separate display.
The controller 32 initializes an internal clock counter T~n~k (see operation
block 316). The controller 32
thereafter compares the clock counter T~,a~ with the cycle counter T~Y~,~
(decision block 318). As referred to herein,
the time variables are counters which may be gauged in minutes or other
increments. Alternatively, the controller
32 may operate on a more continuous time basis. As represented in decision
block 318, if the clock time T~~ is
less than or equal to the cycle time T~,~, then the system has not been in
operation for the full cycle time of the
cell 24. In this case, the cell 24 is energized or remains energizes, as
represented in operation block 320. The
controller 32 waits one time increment, as indicated in operation block 322,
and then increments the clock time T~~
(see operation block 324). The 'controller 32 again compares whether the clock
time Tdock is less than or equal to
the cycle time T~,~ (see decision block 318). This routine continues until the
clock time Tdo~ reaches or exceeds
the cycle time T~,~. In the example where the cycle time T~,~,e is set at 10
minutes, the system and cell 24 will
be in operation until the clock time reaches or exceeds 10 minutes.
Once the clock time Tdo~ equals or exceeds to the cycle time T~,~n. the
controller 32 compares the clock
time Tdo~ against the duty time Td~,Y, as represented in decision block 326.
In the present example, the duty time
Td"n, is set at 20 minutes and the clock time Tda~k is only at 10 minutes when
the initially compares these times.
If the clock time T~,o~k is less than the duty time Tduty, the controller 32
will turn off the halogen generator (operation
block 328). The controller 32 waits one time increment, as indicated in
operation block 330, and then increments
the clock time Tdack (see operation block 332). The controller 32 again
compares whether the clock time Tdo~k is
less than or equal to the duty time Td~,v (see decision block 326). This
routine continues until the clock time Tdack
reaches or exceeds the duty time Td~,Y.
When the clock time T~,o~k reaches or exceeds the duty time Td~,~ the system
has been operational for one
complete duty cycle and is ready to be reset. The controller 32 reinitializes
the clock time T~,o~k, as represented
in operation block 334, and the duty cycle begins with the controller 32
stepping through the operating steps
described above.
At any time during the duty cycle, the user may reset the cell cycle time in
T~,~,e (see operation block 312).
Resetting the cycle time T~,~ affects the clock timing cycle (represented by
decision block 318 and operation blocks
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320-324). If, however, the system is completing a duty cycle after the cell 24
has been on for its set cycle time,
then the new cycle time T~,~k will take affect when the system resets for the
next duty cycle.
Figure 17b depicts a flowchart which illustrates the general operation of the
controller 32 when operated
to automatically actuates the halogen generator 20, depending upon the level
of sterilant within the spa water. In
this automatic mode, the cell 24 is not on for any predetermined cycle time,
but is instead turned on only when the
halogen concentration in the spa body goes below a set level. The halogen
concentration in the water within the
spa body is determined by sensing the oxidation-reduction potential (ORP) of
the water. A measurement of the ORP
indicates the ionic potential within the water, which is proportional to the
number of free ions therein. As mentioned
above, the number of free halogen ions, such as chlorine or bromine, is
preferably maintained at a minimum level so
as to sanitize the spa.
With reference to Figure 17b. the user or manufacturer of the spa initially
sets several parameters to control
how long the cell 24 will be turned on when the ORP falls below a particular
level (see operation block 340). These
parameters may include the size of the spa body, an estimation of the amount
of usage or usage factor, or other
such parameters. These parameters allow the controller 32 to determine the
cell cycle T~,~,, as represented in
operation block 342: Conversely, the user or manufacturer may directly input
the cell cycle time T~,~, into the
controller 32 (not illustrated). The user then sets an ORP sampling interval
To,~ (operation block 344). The ORP
sampling interval To,~ is somewhat like the aforementioned duty cycle time
Td~,Y in the time based control system
diagramed in Figure 17a. That is, the controller 32 samples the reading from
the ORP sensor 252 (as represented
in operation block 346), at the preset intervals ToRp.
Prior to sampling the ORP sensor 252, however, the controller 32 turns on the
cell motor 28 (see operation
block 348) to provide flow across the ORP sensor 252. The sensor 252 gradually
polarizes when immersed in
essentially stationary water and the flow across the sensor 252 acts to re-
calibrate it and ensures an accurate
reading.
After sampling the ORP sensor 252, the controller 32 compares the resulting
voltage level ORP with a
constant (see decision block 350). The constant is determined by the preferred
ionic potential of the water, which
is related to the amount of sanitizing halogen therein. Although this constant
may be varied by several factors, it
is typically between 600 and 700 milliVolts, and most preferably is about 650
millillolts.
If the oxidation reduction potential is greater than about 650 milliUolts,
then the halogen concentration is
sufficient within the spa body 168 and the controller 32 turns off the cell
motor 28 (operation block 352) and the
cell 24 (operation block 354). The controller 32 indicates the off status of
the halogen generator ZO (see operation
block 356). As described above, this display may involve an LED indicator
which is visible through the spa body
(e.g., on the indicator ring 270) and/or an LED indicator located an exterior
access panel of the controller 32 (e.g.,
the indicator light 302 on the controller 32).
The controller 32 then initializes the Block time T~,o~k (operation block 358)
and waits one time increment
(operation block 3601, before incrementing the clock time T~,o~k (operation
block 362). After incrementing the clock
time Tuo~, the controller 32 compares the clock time T~,o~k with the sampling
interval of the ORP sensor TaRp, as
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represented in decision block 364. If the clock time T~,a~k does not equal or
exceed the sampling interval of the ORP
sensor Ta,~, the controller 32 waits one time increment (operation block 360)
before again incrementing the clock
time Tda~ (operation block 362). After incrementing the clock time T~~o~k. the
controller 32 compares the clock time
T~~ with the sampling interval of the ORP sensor ToAP, as represented in
decision block 364.
Once the clock time T~,o~k equals or exceeds the sampling interval of the ORP
sensor To,~, the controller
32 energizes the motor 28 of the halogen generator 20 (see operation block
348) and re-samples the reading from
the ORP sensor 252 (see operation block 346). The controller 32 then compares
the resulting voltage level ORP with
the constant (see decision block 350). If the oxidation reduction potential is
greater than about 650 millillolts, then
the particular halogen concentration is sufficient within the spa body 168 and
the controller 32 turns off the cell
motor 28 (operation block 352). The controller 32 then proceeds through the
above described timing routine until
its time to take another sample reading from the ORP sensor 252.
If the oxidation reduction potential falls below about 650 millivolts, the
controller 32 turns on the cell 24
(see operation block 366) to replenish the halogen concentration within the
spa body 188. The controller 32
indicates the active status of the halogen generator (see operation block 368)
by lighting an LED indicator which is
visible through the spa body (e.g., on the indicator ring 270) andlor located
an exterior access panel of the controller
32.
The controller 32 initializes the clock time T~,a~, as represented in
operation block 370. and waits one time
increment (operation block 372) before incrementing the clock time T~,o~k
(operation block 374). The controller 32
then compares the clock time T~,o~k with the cycle time T~,~,e, as represented
in decision block 376. Before the clock
time Tdo~ reaches ar exceeds the cycle time T~Y~,e, the controller 32 repeats
the above timing cycle (represented by
operation blocks 372-374 and decision block 376). When the clock time T~,a~k
equals or exceeds the cycle time T~,~~
indicating the cell 24 has been on for the desired period (see decision block
376), the controller 32 turns off the
halogen generator 20 (see operation blocks 352, 354). The controller 32 again
indicates the inactive status of the
halogen generator 20 (see operation block 356) by lighting the LED indicator
which is visible through the spa body
on the indicator ring 270 andlor located an exterior access panel of the
controller 32. At this point, the controller
32 returns to the timing cycle between sampling intervals, which was described
above and is represented by
operation blocks 360-362 and decision block 364.
It should be noted that the cell 24 is deactivated (see operation block 354)
before the ORP sensor 252 is
sampled (see operation block 346). This is important because the ORP sensor
252 is grounded and would be
influenced by the potential between the cell electrodes if the cell 24 were
energized.
With the cell 24 turned off and the next sampling interval ToRP reached, the
halogen level in the spa water
may still be insufficient. The controller 32 reactivates the cell 24 (see
operation block 366) for another halogen
generating cycle. This continues until the oxidation reduction potential
reaches or exceeds a predetermined level.
It can thus be appreciated that the operation system diagramed in Figure 17b
is completely automatic and will
maintain the proper halogen level within the spa at all times.
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Controller Operated Descalina Cycle
The controller 32 also can control the operation of the descaling cycle of the
cell 24. In the illustrated
embodiment, the controller 32 monitors the current draw of the motor 28 of the
halogen generator 20. As scale
builds up on the electrode surfaces within the cell 24, the motor 28
experiences more drag and additional loading.
This added load translates into a current increase through the motor 28 which
the controller 32 can monitor. The
controller 32 implements a descaling cycle implemented when the current
increases by a predetermined percentage,
such as, for example, a 20~ increase from normal current draw of the motor 28.
Sensing the motor current will also indicate a problem with loss of fluid
prime within the halogen generator
20. If there is no fluid in the cell assembly 22, the motor 38 will experience
a dramatic reduction in load and
associated decrease in current flow. A significant drop of motor current, such
as, for example, 50% or greater, may
be indicative of a loss of prime. In such a case, the controller 32 should
deactivate the halogen generator 20.
Occasionally, massive scale buildup followed by a cleaning cycle will dislodge
a large quantity of scale leading to
a clog which can "seize" small motors. In this situation, the controller 32
can sense the rapid increase in current
, draw by the motor 28 and trigger a rapid series of motor reversals to
dislodge the clog.
In all of these cases, the current through the motor 28 is detected in
conventional ways and this
information is used by the controller 32 to instigate various responses
described. The specific circuit diagrams and
logic used are believed within the scope of experience of one skilled in the
motor feedback and control art and will
not be described herein.
The current through the cell 24 may also be monitored as a means of
determining the timing and duration
of cell operation. More specifically, as scale builds up, the cell current
will increase. In this situation, the controller
32 will run the cell 24 for a longer period than normal to compensate for the
reduced halogen concentration
generated by a less than efficient, or scaled cell. Optionally, the operation
of the cell 24 may coincide with the
operation of the spa jet booster pump or air injection blower to increase the
halogen generation in periods of
increased need.
Although this invention has been described in terms of certain preferred
embodiments, other embodiments
that are apparent to those of ordinary skill in the art are also within the
scope of this invention. Accordingly, the
scope of the invention is intended to be defined by the claims that follow.
