Note: Descriptions are shown in the official language in which they were submitted.
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1 CENTRIFUGAL PUMP HAVING SEMI-AXIAL DIFFUSION
AND DUAL DISCHARGE FOR HYDROMASSAGE BATHTUB UNITS
Background of the Invention
1. Field of the Invention
This invention relates to a centrifugal
pump for hydromassage bathtub units. More particul-
arly, it concerns a cen~rifugal pump having a
single, centered inlet port, upper and lower
discharge ports, an impeller configured for semi-
axial diffusion of fluid within the pump, and a
fluid directing diffuser plate.
Background Art
Hydromassage bathtub units typically
employ a centrifugal pump to circula~e water
within a tub. The pump is connected by a 1uid
line to nozæle jets fitted in the sidewall of a
tub. Circulation of pressurized water delivered
to the tub through the sidewall nozzles provides atherapeutic, massaging bath.
Installation of hydromassage units is
subject to several government promulgated heal~h
and safety regulations. The amount of water
retained in a hydromassage unit when not in use,
for instance, can be no more than a specified
amount such that the build-up o:E algae and slime
is inhibited. In that regard, all piping in
the system must have a minimum slope so that the
piping will self-drain when the bathtub is empty.
Additional design constraints stem from the fact
that, at least in hydromassage bathtub units
installed in the home, the pump and associated
plumbing are preferably installed out of view.
Pumps for hydromassage bathtub units, thereore,
A~ ~ag~
~20~.t~3
1 have typically been installed under the apron of
the bathtub in the space between the tub sidewall
and the wall of the room in which the tub is
installed.
The previous pumps used in conjunction
with hydromassage bathtub units have had a single,
centered inlet port and a single discharge port.
The discharge port has been placed in an uppermost
position relative to the p~np casing such that
gases trapped within the pump casing can vent through
the discharge port. Previous pumps, therefore,
have only drained to a level slightly below the
inlet port when the pump is not in operation and
substantial amounts of water have been retained in
the pump casing. Although drfl;n;ng of th~, pump
casing could be accomplished by providing a d~ain
pipe in the lower portion of the pump, such a drain
pipe would decrease the output pressure of the fluid
at the sidewall jet nozzles. Moreover, merely pro-
viding a conventional pump with a lower dischargeport in connection with an uppermost discharge port
would not solve the drainage problem, since the
piping from such a lowermost discharge port would
have to slope downwardly to ensure drainage of the
Pump when the pump is not in use. In this regard,
conventional pump units have been relatively bulky,
and it is not possible to place a conventional purnp
high enough under the apron of a bathtub so that
a lower discharge port from the pump would be
higher than the bathtub sidewall jet nozzles. It
is to be understood that the jet nozzles must be
above a certain m;n~m1lm height in the bathtub to
provide an adequate stream of circulating water
for therapeutic purposes. Merely decreasing the
size of a conventional pump so that it may be placed
1 higher under the apron of a bàthtub results in a
corresponding decrease in the output potential oE
the pump.
A pump for hydromassage bathtub units
that included both a lowermost and uppermost dis-
charge port, and which was small enough to be
mounted at an elevated position under a bathtub
apron, and would deliver an adequate flow and
pressure of water for therapeutic massage purposes,
would be a decided advantage.
Summary of the Invention
The problems outlined above are in large
measure solved by the centrifugal pump for hydromassage
bathtub units in accordance with the present
invention. That is to say, a pump in accordance
with the present invention includes upper and lower
discharge ports, is substantially smaller than that of
conventional pumps now in use for hydromassage
bathtub units, and delivers an output flow and
pressure of fluid from the pump more than adequate
for hydromassage application.
The pump for hydromassage bathtub units
in accordance with the present inventio~ broadly
includes a pump casing having a centered inlet
port and upper and lower discharge ports, an
impeller rotatably mounted within the pump casing
modified for semi-axial discharge of fluid from
the impeller, and a diffuser plate for distributing
the fluid discharged from the impeller around the
circumference of the pump casing at a uniform
pressure.
1 Brief Description of ~he Drawings
Figure 1 is a side elevational view of a
bathtub having a hydromassage unit installed
therein and employing a centrifugal pump in accord-
ance with the present invention;
Fig. 2 is a side elevational view of a
pump in accordance with the present invention;
Fig, 3 is a front elevational view of a
pump in accordance with the present invention;
Fig. 4 is an enlarged vertical sectional
view taken along the line 4-4 of Fig. 3;
Fig. 5~is a sectional view taken along
the line 5-5 of Fig. 4 with portions of the pump
broken away for clarity;
Fig, 6` is an enlarged fragmentary vertical
sectional view of a portion of the diffuser
assembly;
Fig. 7 is an enlarged fragmentary ver~ical
sectional view of the diffuser assembly; and
Fig. 8 is similar to Fig. 7 but with a
peripheral edge of ~he diffuser removed for clarity.
Deta`iled Description of the Drawings
A hydromassage bathtub unit 10 employing
a pump 12 in accordance with the present invention
is depicted in Fig. 1 in conjunction with a bathtub
14. The bathtub 14 includes a plurality of nozzle
jets 16 connected to pump 12 by a fluid line 18,
and a pump intake aperture 20 connected to pump 12
by a line 22. The pump 12 is supported on a stand
24, and is located under the apron portion 26 of
the tub. The tub includes a drain 28.
Pump 12 includes a motive section 28
comprising an electric motor 30 having a drive
shaft 32, and a fluid directing section 34, both
1 mounted on base stand 36. As best seen in Fig. 4,
the fluid directing section 34 includes an intake
portion 38 comprising an inlet port 40, impeller
42 and impeller chamber 44. The fluid directing
section 34 also includes a discharge portion 46
that includes upper and lower discharge ports 48,
50, diffuser structure 52 and discharge chamber
54. A front shroud 55 fits over the fluid directing
section.
The impeller 42 includes a front plate
56, rear plate 58, and a plurality of arcuate
impeller arms 60 interposed between and fixedly
interconnecting the front and rear plate.s. The
front plate 56 includes a centered fluid receiving
aperture 62 coaxially oriented with inlet port 40.
A circular flange 64 extends around aperture 62
and projects outwardly from the front plate 56. A
support shaft 66 projects rearwardly from rear
plate 58, and is fixedly received on motor shaft
32 for rotation therewith. A water deflecting
slinger 68 is fixedly mounted on shaft 66.
The front shroud 55 is connected to a
support bracket 70 by a plurality of screws (not
shown). Diffuser plate 72 is interposed between
front shroud 55 and bracket 70. Shaft 66 is
received through a centered aperture within bracket
70, and an annular washer 74 is supported by the
bracket and surrounds shaft 66. A sealing washer
76 is supported by collar 78, and is maintained in
water tight sealing relationship with washer 74 by
spring 8Q.
Front shroud 55 includes annular flanges
81, 82 and 84 projecting outwardly and forwardly
from upper discharge port 48, inlet port 40 and
lower discharge port 50 respectively to define
1 axially oriented channels. Impeller chamber 44 is
defined in part by an annular sidewall 86 extending
inwardly from front shroud 55. Sidewall 86 includes
a lowermost drainage slot 88. The uppermost
portion of front shroud 55 defines a rearwardly
directed channel 90.
Referring to Figs. 6, 7 and 8, it will
be seen that the diffuser structure 52 is comprised
in part from structure associated with bracket 70,
and in part from structure associated with diffuser
plate 72 that complementally engages the bracket
70. The bracket diffuser structure includes a
plurality of circumferentially spaced apart,
outwardly extending vanes 92. Each vane 92 includes
a radially oriented face 94, a sloped, generally
axially oriented, fluid directing face 96, and an
arcuate fluid directing face 98. The faces 94
include a diffuser plate engaging rib 99. Diffuser
plate 72 includes a plurality of circumferentially
2Q spaced apart vanes 100 that include a generally
axially oriented, sloped face 102 that essentially
comprise extensions of the sloped faces 96 of
bracket vanes 92. Diffuser plate 72 also includes
a plurality of circumferentially spaced apart,
channel defining projections 104 that include an
axially oriented face 106 and radially oriented
face 108. The diffuser plate 72 and bracket 70
cooperatively define, through their vanes and
projections, a series of water directing channels
110 that direct fluid flow from the impeller 42,
outwardly through channels 110 into discharge
chamber 54. Discharge chamber 54 includes flow-
blocking stop 112.
In operation, pump 12 is mounted as high
as possible under apron 26 of tub 14 such that the
1 lowermost discharge port 50 is at a higher elevation
than the jetted nozzles 16. Although the perspective
of Fig. 1 permits a showing of only the lower
discharge port 50 connected to tub nozzle jet 16,
it is to be understood that in normal operation
both the upper and lower discharge ports 48, 50
are connected to nozzle jets 16. The upper discharge
port 48 can be vented through either rearwardly
acing channel 90, or the forwardly facing channel
defined by flange 80, although normally only one
of the two channels will be used and the other
channel will be plugged.
Once the tub 14 is filled with water,
the pump 12 can be operated and water will be
circulated through intake aperture 20 through
fluid line 22 to the pump inlet port 40. Water
taken in through inlet port 40 is directed through
impeller aperture 62 and thrust radially outwardly
by impeller arms 60. Discharge from the impeller
arms 60 is directed semi-axially due to the fact
that impeller rear plate 58 is of a smaller diameter
than the impeller front plate 44. The smaller
relative diameter of rear plate 58 therefore
permits the impeller chamber 44 to be of a diameter
only slightly greater than the diameter of front
plate 56, thereby reducing the overall size of the
pump. Water is directed from the impeller 42
through diffuser channels 110 and is directed
outwardly by the diffuser structure 52 so as to
provide essentially uniform fluid pressure around
the perimeter of the discharge chamber 54. Flow
blocking plate 112 prevents fluid within the
discharge chamber 54 from merely circulating in a
rotational manner, and the fluid within the discharge
chamber is therefore vented through the upper and
2~
1 lower discharge ports 48, 50.
It is not unusual during normal operation
of a centrifugal pump for gas to be accumulated
within the discharge chamber. As will be appreciated,
gases within the discharge chamber 54 of the pump
12 will automatically rise and vent through the
uppermost discharge port 48.
Water r~mAin;ng within the fluid directing
section once the operation of pump 12 is secured,
will drain through the lowermost discharge port
50. Water within the discharge chamber 54 will
drain directly through the port 50, and water
within the impeller chamber 44 will vent through
slot 88 and then through discharge port 50.
