Note: Descriptions are shown in the official language in which they were submitted.
CA 02775456 2012-04-25
SHOWER HEAT EXCHANGER WITH CLOG-REMOVABLE DRAIN
BACKGROUND OF THE INVENTION
Many ways of recovering some of the heat in the grey waste water of a shower
to
preheat the incoming cold water have been attempted in the past. The prior art
of
Hunter's Shower Bath Economizer (US Patent 4,372,372) uses a chamber below the
drain with a helical coil within forming a type of coil-in-shell heat
exchanger. Nobile, in
his heat recovery device of US Patent 5,791,401, uses a coil of tubing
containing the
incoming cold water wrapped around a formed section of the drain pipe to
recover heat
from the waste water. Vasile et al. in his US Patent 4,619,311 uses a
contrafiow heat
exchanger formed around the straight drain pipe to the sewer to recover some
heat.
Sheffield, in his US Patent 4,821,793, uses an above the floor tub and shower
floor heat
exchanger for the same heat recovery function.
The prior art of Cardone's US Patent number 4,304,292 for a shower waste heat
recovery system is described in detail in Figures 1-6 provided below. While it
is a
workable system for recovery of heat from the grey waste water, it did have a
shortcoming such that it was not compatible with some plumbing codes regarding
removability of clogs in the drain.
CA 02775456 2012-04-25
BRIEF DESCRIPTION OF THE DRAWINGS OF THE PRIOR ART
OF CARDONE 292:
Fig. 1 is a simplified diagrammatic view of the water connections in Cardone
292
to and from a household shower embodying a conservation technique according to
the
prior art;
Fig. 2 is a front elevational view, on an enlarged scale, illustrating one
embodiment of a heat exchanger in Cardone '292 for practicing the method and
for using
the preferred structure of the prior art;
Figs. 3 and 4 are simplified instruction diagrams illustrating the boiler-
heated
warm water input to the household shower in Cardone 292;
Fig. 5 is a plan view of a removable floor panel of this shower embodiment in
Cardone '292; and
Fig. 6, like Fig. 5, is also a plan view, but on an enlarged scale and
illustrating the
heat exchanger in Cardone '292 which is situated below the floor panel of Fig.
5.
In the prior art of Cardone '292, with the significant shortcoming
subsequently
noted above, it already is known that use is made of discharging water from a
household
shower, either of the tub-type 30 or stall-type 32, to effectuate significant
energy
conservation, wherein as is typically the case, the household has a boiler 34
of the type
which includes a storage tank 36 which tank, depending upon boiler-heated
water
available for use for such purposes as showering at locations 30, 32.
The prior art will be understood for the set-up for the showers 30 or 32 to
include
a tub drain conduit 40 or a stall shower drain 42, wherein the drain channels
the
discharging water through a trap of U-shaped design designated 44, on its way
to a sewer
connection 46.
It is known that the water discharging through the U-shaped conduit 44 is, in
most
cases, tepid, being a mixture of boiler-heated warm water and a cold water
input to the
showers, 30, 32.
In the above respect, it has been noted that the discharging water that
normally
drains is approximately 100 Fahrenheit at the time encountering the U-shaped
conduit
44. This otherwise wasted 100 Fahrenheit water is effectively passed in heat
exchange
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relation to the cold water input, which in the community of Wantagh, N.Y., is
typically
supplied at 50 Fahrenheit. The heat exchange has been found in practice to
provide a
lukewarm water source at approximately 65 to 75 Fahrenheit for delivery to
the faucet
connection 58, 60 of the showers 30, 32. This increase in approximately 150 to
25
Fahrenheit significantly diminishes the amount of boiler-heated water that is
required to
be delivered to the showers 30, 32. While the beneficial results depend on
different
operating conditions and thus cannot be defined with precision, in practice
use of the
invention for 28 successive showers at a selected tepid temperature of 110
Fahrenheit for
the premixed water and during a selected duration time for showering of 10
minutes
which consumed approximately 15 gallons of the prior art set-up of Fig. 1.
Cardone's US patent 4,304,292 for heat conservation, unfortunately with the
shortcoming noted above, is nevertheless commendably practiced as best
illustrated in
Figs. 5 and 6, which correspond to Figures 8 and 9 of Cardone '292, as well as
what is
shown in the crossectional detail view of Figure 10 of Cardone '292, in which
a floor of
shower 30' includes a base 100 in the upper face or surface 102 of which there
is
embodied, in any appropriate manner, a spiral trough, generally designated 104
in Fig. 6
and the individual helical turns of which are designated individually and
collectively 106.
By slight increases in depth of the individual helical turns 106 the trough
104 is pitched
to drain towards central opening 108 of base 100 of Figure 10 of Cardone '292õ
in which
opening there is an appropriate drain fitting 110 which mounts a depending
conduit 112
which will be understood to discharge into a sewer or the like. In accordance
with the
prior art, a pipe 114 suitable for flowing water to the shower 30' and itself
in a helical
configuration as illustrated, is deposited in the correspondingly helically
configurated
trough 104. That is, and as is perhaps best illustrated in Fig. 6, the
individual helical
.. turns of the spiral pipe 114, designated individually and collectively 116
are each located
in a cooperating one of the helical turns 106 of the spiral trough 104.
Connected at the
center, as at 118 to the spiral pipe 114, is the shower cold water inlet pipe
or conduit 122,
as shown in Prior Art Figure 6 herein, and in Figure 9 of Cardone '292. The
cold water
outlet connection from the spiral pipe 114, designated 120, extends from the
outermost
helical turn and is connected to the shower faucet cold water conduit 56'. As
a result, the
cold water input to the shower 30' is delivered through the helical heat
exchanger 114
3
prior to delivery through the shower head 67'. More particularly, cold water
from a
suitable source initially flows through the inlet pipe 120, then successively
through each
of the helical turns 116 to the helical pipe 114, and then finally through the
outlet pipe
120 into the faucet pipe 56' where, upon opening of the valve 58', the water
is discharged
through the shower nozzle 67'.
However, the prior art of Cardone '292 does not reveal a shower heat recovery
system using a high efficiency flat plate heat exchanger with specific
features for drain
clog removal.
OBJECTS OF THE INVENTION
It is therefore an object of the present invention to provide a shower heat
exchanger which preheats incoming cold street water while reducing the need
for a hot
water heater/boiler to supply hot water for a shower.
It is also an object of the present invention to provide a shower hot water
heat
exchanger which complies with applicable plumbing codes requiring access for
removing
clogs and which promotes the removal of standing stagnant water.
Other objects which become apparent from the following description of the
present invention.
SUMMARY OF THE INVENTION
In keeping with these objects and others which will become apparent, the
shower
heat exchanger system of this invention, while complying with plumbing and
sanitary
standards for clog removal from drains, offers very high efficiency of heat
recovery using
a unique flat plate heat exchanger strategically placed below a tub or shower
stall (or
even below the bathroom floor).
The concepts of this invention are designated by the acronym SHWERDTm which
is derived from "Shower Hot Water Energy Recycling Device".
In accordance with one embodiment of the present invention, there is provided
a shower
heat exchanger system comprising: a tub/shower stall with a single drain for
draining grey waste
water; a shower in said tub/shower stall haying a shower head, sources of
incoming cold and hot
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water including cold and hot water valves with handles, respectively; a mixing
area for the
incoming cold and hot water prior to delivery to said shower head; a heat
exchange system for
preheating incoming cold water to said cold water valve located below said
tub/shower stall; said
heat exchange system comprising a housing containing a flat plate of thermally
conductive
material having a gray water chamber above said flat plate within said
housing, and an incoming
cold water chamber below said flat plate within said housing; said gray water
chamber having an
inlet through a top wall of said housing at one end adjacent said drain for
receiving said gray water
being discharged through said drain, and having an outlet through a wall of
said housing at an
opposite end of said gray water chamber discharging the gray water directly
into a sewer system,
said gray water spreading over a complete width and length of said flat plate
in a straight and
uninterrupted flow path as said gray water moves from said inlet to said
outlet of said gray water
chamber, said heat exchange system being a dry base structure thereby avoiding
any leaking gray
water from intruding into potable water; said gray water chamber inlet, the
height throughout said
gray water chamber, and said gray water outlet being sufficiently large as to
accommodate a ball
of about two inches in diameter to accommodate a snaking cable to remove any
clog, in accordance
with requirements of the Uniform Plumbing Code; said gray water chamber having
means for
guiding said snaking cable into the outlet of said gray water chamber to
facilitate any removal of
a clog; said incoming cold water chamber having an inlet adjacent the outlet
of said gray water
chamber and an outlet adjacent the inlet of said gray water chamber so that
flows in both chambers
are countercurrent to each other; said incoming cold water chamber having a
serpentine flow
pattern and being insulated from below; whereby heat is transferred from the
grey waste water
spreading over said flat plate to preheat the incoming cold water flowing
underneath said flat plate
in contact with a bottom surface of said flat plate; said cold water valve
directing flow of said
preheated incoming cold water from said incoming cold water chamber to said
mixing area so that
hot water from a water heater is mixed with said preheated incoming cold water
in said mixing
area as a substitute for the incoming cold water that would be normally
plumbed to the discharge
shower head, thereby reducing the amount of hot water flow required to achieve
the desired
showering temperature.
The standard drain inside the tub or shower stall accepts the grey waste water
and directs
it in a precise manner to impinge upon one end of a slightly titled top plate
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(preferably copper) of the heat exchanger. This top plate is fastened robustly
to a flat
heat exchanger lower plate (preferably made of a sheet of rigid synthetic
material such as
PVC approximately 1/4"-3/8" thick or of a heat conductive material, such as
copper). The
lower plate is thermally insulated from below and on its sides. The lower
plate has a
serpentine pattern routed into its top side to a shallow depth such that the
top plate, when
fastened and sealed to it, forms a continuous chamber or serpentine conduit
for
containing the cold water flow. Thus it is understood that heat is transferred
from the
waste water falling on the top plate and spreading over it to the cold water
flowing
underneath the top plate in a tortuous serpentine pattern in contact with the
bottom
surface of the top plate. The cold water is thereby preheated and used as a
substitute for
the cold water that would be normally plumbed to the shower head. This
therefore
reduces the amount of hot water flow required to achieve the desired showering
temperature. The geometric relationship between the drain and the placement of
the heat
exchanger underneath guarantees the counterflow of the waste water flowing
atop the
heat exchanger and the cold water flow going back and forth across the
underside of the
top plate and inching its way toward the vicinity of the tub drain, which is
the hottest
portion of the top heat exchanger plate. In this manner, the greatest rise in
temperature of
the preheated cold water is achieved, since the waste water enters the sewer
outlet, at a
temperature that can be significantly lower than that of the preheated cold
water, while
still transferring heat to the even colder inlet cold water, entering at the
waste water
discharge end of heat exchanger. At the top end of the heat exchanger near the
drain
outlet, the waste water is hotter than the preheated cold water beneath, so
that it is still
raising the temperature of the preheated cold water, just before discharge
through the
shower head.
In a typical example, cold street temperature water of about 50 degrees
Fahrenheit
is exposed to typical hot shower water of about 120 degrees Fahrenheit through
the heat
exchanger. This exposure quickly raises the cold water to a preheated
temperature of
about 90 degrees Fahrenheit, which mixes with a reduced amount of hot water,
to a final
temperature, also of about 102-108 degrees Fahrenheit, which also reduces the
need for
using a hot water heater/boiler to heat hot water for a shower.
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One way to insure the efficiency of the heat exchanger of this invention is to
have
many reversals of the cold water path close together and with small width. In
another
embodiment, a wide water path is used through the heat exchanger with fewer
reversals
in the serpentine. To increase efficiency, fins are optionally added to the
underside of the
copper plate in the region of the serpentine below that would be wet by the
cold water
flow; this increases the effective area of contact. It is also noted that the
upper plate can
be made integral with the serpentine sections and base supporting the
serpentine sections
by the base plate being made of copper or other heat conductive material, with
the
corrugated walls of the serpentine sections extending upward from the lower
base plate to
the upper heat conductive copper plate, so that the entire heat exchanger unit
is heat
conductive, but thermally insulated on its sides and from below.
The serpentine sections can be either channels cut in the lower PVC plate or
channels formed of copper walls. In addition, the serpentine sections can be
formed from
parallel tubes (of any geometric configuration, round or straight sided, with
flat walls)
with curved or angled manifolds, forming the curved or angled corners
connecting the
straight portions, formed from the parallel tubes. However, whether the bottom
plate is
PVC or copper, since the top plate is a good conductor for spreading heat from
the waste
grey water laterally in case the flow from the drain does not spread evenly;
therefore the
heat must be conducted through the plate to be deposited to the water flowing
under it. It
is beneficial for the heat to stay there and not leak out the bottom or sides
of the base.
This is why the heat exchanger is wrapped underneath in insulating foam or
other
insulating material. The base plate is thermally insulated at the sides and
bottom, such as
by a thick layer of solid or spray-on foam insulator.
In the first embodiment of this invention, the heat exchanger is plumbed
directly
with the cold water supply at the bottom (cold end) with the cold water shower
valve at
the preheated end feeding the shower head mixing area. This means that the
heat
exchanger remains at supply pressure even when the shower is not in use. In an
alternate
embodiment, the plumbing is re-routed to feed the cold end of the heat
exchanger through
the shower cold water valve with the preheated cold water outlet of the heat
exchanger
directly plumbed to the shower head mixing area. While the operation to the
user is
identical, the heat exchanger is no longer pressurized when the shower is not
in use. This
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is called a "Dry Base Exchanger" configuration, whereby if the heat exchanger
were
damaged or punctured, it would not leak profusely, since it is not
pressurized.
In the first embodiment, the drain is preferable at the end of the tub
opposite the
shower head, while the sewer connection is retained at its normal location at
the shower
.. head end. This can be easily accomplished by turning the tub around since
it is reversed
from normal practice. Note that an alternate embodiment retaining the drain at
the shower
head end of the tub is also possible, but the sewer connection will then be at
the opposite
end. Either will perform equally, but one may be easier to install than the
other.
In yet another embodiment, a service chamber is appended to the tub at the end
near the sewer connection which discharges grey water after it has run down
the heat
exchanger top plate. This chamber has an easily removable top cover permitting
direct
access to the sewer opening so that a plumber's snake can be directly entered
thereby
bypassing the excursion down the length of the top plate.
Because of the continuous preheating of cold inlet water, there are less BTU's
consumed, and subsequent showers remain warm even after multiple showers.
BRIEF DESCRIPTION OF THE DRAWINGS OF THE INVENTION
The description of the invention which follows, together with the accompanying
drawing, should not be construed as limiting the invention to the example
shown and
described, because those skilled in the art to which this invention appertains
will be able
to devise other forms thereof The drawings are diagrammatic, and not drawn to
scale of
actual use.
Fig. 7 is an exploded perspective view of the bathtub, partially in section,
and of
the heat exchanger, both in accordance with the present invention; wherein the
flow of
street water being preheated is indicated by single line arrows and wherein
the flow of
exiting grey hot water is indicated by double line arrows;
Fig. 7A is an exploded perspective view in partial cutaway, similar to Figure
7,
but optionally showing the addition of fins to the underside of the top plate
of the heat
exchanger to enhance heat transfer;
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Fig. 7B is a side view crossection of the assembled heat exchanger of Figure
7A
showing the added fins immersed in cold water flow within the serpentine
channels;
Fig. 7C is a close-up detail perspective view of a fluid path schematic
diagram of
an alternate embodiment for serpentine sections where parallel round tubings
are
connected by corner sections;
Fig. 7D is a close up detail perspective view of a portion of parallel tubings
of
angled corrugated fluid path sections in serpentine configuration, with
straight
rectangular walls connected by angled corner sections;
Fig. 8 is a side elevational view, in assembled condition, of the bathtub and
heat
exchanger of Fig. 7;
Fig. 9 is a partial elevational view, in section, of the structure noted by
the
reference arrow 9 in Fig 8;
Fig. 10 is also a partial elevational view, in section, but of the structure
noted by
the reference 10 in Fig. 8;
Fig. 11 is a side view schematic representation illustrating the cold water
piping
flow of a Dry Base Exchanger embodiment whereby the input to the heat
exchanger is
controlled by the cold water valve;
Fig. 12 is a side view schematic showing the heat exchanger of this invention
located below the bathroom floor and servicing a tub above;
Fig. 13 is a side view schematic showing the heat exchanger located below the
bathroom floor and servicing a shower stall;
Figure 14 is a side elevation of an alternate embodiment for a tub with a side
attached service chamber providing unobstructed access to the sewer pipe
connection,
where the side attached service chamber comprises a wide pipe with a breather
cap;
Figure 14A is a side elevational view in crossection of the tub and heat
exchanger
of Figure 14;
Figure 15 is an exploded perspective view of an alternate embodiment, showing
an access plate over the chamber having a pipe wherein the porcelain tub is
shown
separated from the heat exchanger plate, which includes a concave end portion
in the
vicinity of the sewer connection drain, and wherein a series of elevated water-
sealed
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peripheral walls are provided with a minimum 2" clearance under the bottom of
the
tub/shower stall, for removing clogs pursuant to the Uniform Plumbing Code;
Figure 16 is an exploded perspective view of the shower heat exchanger showing
an auxiliary peripheral jet flush-out system, as well as an optional central
divider brace;
Figure 17 is a perspective view of a factory produced tub/shower stall modular
unit with liner walls having the show heat exchanger built integral therein;
and,
Figure 17A is a perspective view of a factory produced shower stall modular
unit
with liner walls having the show heat exchanger built integral therein.
.. DETAILED DESCRIPTION OF THE INVENTION
In the preceding discussion of the prior art US patent 4,304,292 of Cardone,
reference was made to a shortcoming. This shortcoming is, as required by the
sanitary
code of most intended sites of use, that the system used have the ability of
clog-
.. removable functioning in the drain to the sewer. In the system now to be
described, it
should be readily understood that hypothesizing the "clog" as a two-inch-
diameter ball
stuck in the drain to the sewer, that the removal with a snaking cable or the
like is readily
achieved. Thus this invention complies with the Uniform Plumbing Code.
The present system of heat recovery of this invention has no such
shortcomings.
.. Shown in Figs. 7 and 8, in the former in exploded relation, and in the
latter in assembled
relation, is a bathtub, generally designated 11 in its use mode as illustrated
in Fig. 8 as a
shower, as noted by arrow 13, received from a shower head 15, the volume of
the shower
13 being a function of the valving of two on/off faucets 17, one for cold
water and the
other for boiler-heated water, wherein the result of this mixing of inputs
results in a tepid
temperature of the shower 13, as previously explained in the discussion of the
prior art.
As shown in Figures 7-10, the tepid water 13 drains at the remote bathtub end
19,
i.e. an end usually not the conventional bathtub location, and flows, as noted
by single
line arrows 21 in the clearance 23, which serves as a passageway above the
heat
exchanger 25, emptying as best shown in Fig. 10 in an outlet 27 which is in
fluid
communication with the exiting boiler-heated hot water source used for the
shower 13,
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exiting as grey water, and identified as double line arrows cascading across
heat
exchanger plate 29 and exiting through outlet 27.
The heat exchange function results from the use of a closure plate 29 of
copper
construction material, appropriately attached over a base 31 having edges
bounding a
.. passageway outlet 33 of tepid water 13 exiting from the bathtub remote end
19. As shown
in Figures 9 and 10, base 31 includes a layer of insulation 31a, such as
STYROFOAM
foam or other insulating material, which may be an integral layer, or may be
attached by
spraying or attaching from below. The insulating material can be any kind of
natural or
synthetic resinous cellular material. The insulating layer applies to all
embodiments
.. herein.
Passing in heat exchange with the tepid water 13 is the cold water input into
the
heat exchanger 25, as explained in the previous discussion of the prior art,
the input being
at the heat exchanger end and flowing in a sinusoidal flow pattern, as noted
by arrow 37,
said sinusoidal pattern lengthening the heat exchange duration of the tepid
water and
cold water inputs constituting the showering water 13.
Note in Figure 7 base 31 has few direction reversals. In actuality, much
narrower
water channels 37 formed between sinusoidal heat conductive walls 37' in a
separate
pathway and reversals every 2" or so are used to enhance heat transfer.
Moreover, the
depth is preferably about 1/8" in depth as used, although depth may vary, as
long as
effective heat transfer occurs.
An alternative method of increasing heat transfer from top plate 29 to the
water in
channels 37 is to maintain the broad serpentine pathway of Figure 7, but to
add heat
transfer fins 29A (as shown in Figures 7A and 7B) attached to the underside of
plate 29
and dipping into the water channels below. Heat transfer fins 29A can extend
all the way
.. down from heat conductive plate 29 to base 31, or they can extend partially
down (not
shown).
Although drawing Figure 7 shows a meandering serpentine pathway which is in
contact with the heat exchanger plate 29 above, in Figure 7C there is shown a
fluid path
schematic diagram of an alternate embodiment for serpentine sections where
parallel
round tubings 37a are connected by corner sections 37b, and wherein the
tubings contact
the heat exchanger plate 29 at the tangent where the tops of each tubing
portion 37a
CA 02775456 2012-04-25
contact heat exchanger plate 29 above. Optionally, in another embodiment,
where the
tubes are heat conductive (such as copper), use of heat exchanger plate 29 can
be
dispensed with. In that use, the hot shower grey water can flow over the tops
of round
tubings 37a without heat exchanger plate 29, so that heat is exchanged
directly through
the tubings 37a to the cold street water being preheated.
Likewise, in Figure 7D there is shown a portion of parallel tubings of angled
corrugated fluid path sections 38 in serpentine configuration, with straight
rectangular
walls 38a connected by corner sections, where the tops of the straight walls
38a contact
the flat heat exchanger plate 29 above. In Figure 7D the walls 38a are
foreshortened in
the hollow corner areas 38b, to provide the serpentine pathway for the
incoming cold
street water to flow therethrough, forming the preheated water as the cold
water is in
thermal contact with the heat generated by hot shower water passing over flat
heat
exchanger plate 29, located above the serpentine pathway portions 38 formed by
straight
walls 38a. Some of the walls 38c extend at one side all the way to an outer
wall, to form a
closed area, to direct fluid flow around corners and through the serpentine
configuration.
As a result of the foregoing, the "cold" water input into the showering water
13 is
raised to an elevated temperature than it would have had otherwise, with a
first important
consequence that less boiler-heated water 17 is required for the showering
water 13.
A second important consequence is that the just noted savings is achieved by
the
described operating mode which complies with the sanitary code of most
intended sites of
use, i.e. that that system used, as more particularly described and
illustrated in Figs. 7, 8
and 9, have the ability of clog-removable functioning in the drain to the
sewer. For
example, the region below tub/shower stall 19 and above heat conductive plate
29,
through which shower waste grey water passes, is at least two inches in
height, to permit
a snake to clear out that area of any clogs, pursuant to the Uniform Plumbing
Code. To
enhance aiming and movement of the snake, the region near sewer outlet 27 at
the
opposite end of the heat exchanger can be optionally provided with a concave
region 25a
surrounding the sewer outlet 27, as shown in Figure 15, so that when the
distal end of the
snake approaches the sewer outlet 27, it is directed to the sewer outlet 27.
This option is
applicable to any of the embodiments for the heat exchanger of the present
invention.
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The embodiment shown in the side schematic of Figure 11 has two notable
changes from that of Figure 8. The first change is that drain 40 is located at
the same end
as the shower head and valves which is the conventional arrangement. The
second is the
routing of the cold water relative to cold water valve 17 and heat exchanger
25. This
latter routing is called a Dry Base Exchanger.
Figure 11 illustrates a tub 11 with floor sloping downward toward left toward
drain 40 with water 42 discharging through it. Heat exchanger 25 slopes
downward
toward the right with grey water 47 discharging from the top plate to the
sewer
connection and pipe 27 on the end opposite from that of Figure 8 (now placed
away from
.. the shower head). Water heater 45 receives cold water at 50 degrees
Fahrenheit and feeds
120 degree water through hot water valve 46. As opposed to Figure 8 practice,
cold water
is fed directly to cold water valve 17 and then to the cold water input of
heat exchanger
25. It is boosted in temperature to 90 degrees Fahrenheit and connects
directly through
pipe 48 to the mixing region to then be discharged through shower nozzle 15 at
103
degrees Fahrenheit. This Dry Base Exchanger cold water routing through valve
17 prior
to heat exchanger 25 means that exchanger 25 is not pressurized when not in
use. If the
top plate or base portion were to be damaged during the standby period (most
of the
time), it will not leak profusely, damaging the surroundings, since the system
only
contains the water in the serpentine and that in the piping to the shower head
to leak out.
The Dry Base Exchanger piping hook-up is the preferred embodiment and may be
used
as a substitute for the pressurized heat exchanger hook-up in any of the
illustrations and
embodiments shown.
While heat exchanger 25 can be installed below an elevated tub as shown in
Figure 8, the heat exchanger can be conveniently placed below the bathroom
floor
leaving the tub at it's normal height. This is especially convenient if the
bathroom is over
an unfinished basement. Figures 12 and 13 are schematic views showing such an
installation for a tub and for a shower stall respectively. Figure 12 shows
tub 11 with
sloping internal floor 41 at its normal height resting on bathroom floor 52.
Heat
exchanger 25 is installed below floor 52 level and possibly attached to
conveniently
located beam 53. In Figure 13, shower stall 54 rests normally on bathroom
floor 52 while
heat exchanger 25 is below floor 52 level and can be attached to beam 53. Note
that
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concave inner shower stall floor 55 drains atop the heat exchanger top plate
in a similar
fashion to a tub installation.
The embodiment of Figures 14 and 14A show the use of an optional service
chamber 62a attached to the end of tub 11 adjacent to the sewer pipe
connection 64. It has
an easily removed decorative access cover 62. If one looks straight down
chamber 62a
with cover 62 removed, the sewer pipe connection 64 can be see in unobstructed
view at
the bottom of pipe 63a, so that a plumber's snake and/or chemical clog
removers can be
administered along the straight short path 63 (shown in arrows). This direct
access to
sewer connection 64 bypasses the bend at drain 40 and the length of the top
plate 29 of
heat exchanger 25 which would have to be traversed through drain 40 otherwise.
This
area within chamber 61 can also be used to flush out the top plate surface
with a water
hose or pressure cleaner since the entire width of plate 29 is accessible
through it.
Figures 14 and 14A also show a side elevation in crossection of an alternate
embodiment for a tub 60 with side attached service chamber 62a providing
unobstructed
access to the sewer pipe connection 64, where the side attached service
chamber
comprises a wide pipe 63a with a breather cap 61 underneath access cover 62.
Typically,
pipe 63a is a wide pipe of approximately 5" in diameter leading to sewer
connection 64.
As can also be shown in Figure 14, tub 60 having a depth "Dl" of approximately
7"
indicates that the bottom of pipe 63a can be reached with a plumbing snake or
even
manually by a person cleaning pipe 63a with their hand and forearm. Depth D1
can vary
from 2" up to high tube depths of 14 inches or more.
Figure 15 is an exploded perspective view of an alternate embodiment for the
system 60 of Figures 14 and 14A showing an access plate 62 over chamber 63
having
pipe 63a wherein in the porcelain tub 11 is shown separated from the heat
exchanger
plate 29, which includes an optional concave end portion 25a in the vicinity
of the sewer
connection drain 64, and wherein a series of elevated peripheral water sealed
walls 25b-
25e are provided with a minimum 2" clearance under the bottom of the tub 11
for
removing clogs pursuant to the Uniform Plumbing Code 710.3.3, which provides
"In
other than single-dwelling units, the ejector or pump shall be capable of
passing a two (2)
inch (51 mm) diameter solid ball, and the discharge piping of each ejector or
pump shall
13
CA 02775456 2012-04-25
have a backwater valve and gate valve, and be not less than three (3) inches
(80 mm) in
diameter."
Figure 16 shows a shower heat exchanger showing an auxiliary peripheral jet
flush-out system 70 with jets 71 and control valve 72, as well as an optional
central
divider brace 80 for stability. In this embodiment, two separate sets of
serpentine water
channels 37 are provided on each side of the divider brace 80 and flowing
jointly into
drain 40. The auxiliary flush out set of jets 71 can be provided within the
space above the
pair of separate heat conductive upper plates 29 and 29' of the heat exchanger
25 and a
floor of the tub 11 above the heat exchanger 25.
As shown in Figure 17, although the shower heat exchanger 25 can be retrofit
and
sealed to existing tub/shower stalls 11, it is further noted that the heat
exchanger 25 can
be built integral into a factory produced tub/shower stall modular unit 90
with liner walls
91-93 and tub 11 and/or optimal access plate 62.
Additionally, as shown in Figure 17A, although the shower heat exchanger 25
can
be retrofit and sealed to existing tub/shower stalls 11, it is further noted
that the heat
exchanger 25 can be built integral into a factory produced shower stall
modular unit 90a
with liner walls 91a-93a, but with a shower stall 11a, instead of a tub/shower
stall 11
shown in Figure 17, and/or with access plate 62a.
In the foregoing description, certain terms and visual depictions are used to
illustrate the preferred embodiment. However, no unnecessary limitations are
to be
construed by the terms used or illustrations depicted, beyond what is shown in
the prior
art, since the terms and illustrations are exemplary only, and are not meant
to limit the
scope of the present invention.
It is further known that other modifications may be made to the present
invention,
without departing the scope of the invention, as noted in the appended Claims.
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