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Description  |
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BRIEF SUMMARY OF THE INVENTION
This invention relates to a tub assembly and is more particularly concerned
with a heating system for reheating water in a tub.
In the past, tubs which are provided with jet nozzles have been devised for
providing circulating water to the tub. Such a circulating system includes
a motor with a centrifugal pump which takes a suction from the bottom
portion of the tub and delivers the water through an electrical heat
exchanger to the discharge nozzles in the tub for directing the water
against a person occupying the tub. Usually, the water in the tub has been
delivered to the tub at the appropriate temperature from the hot water
system in a house and the purpose of the heater is to maintain the water
in the tub in an appropriately heated condition. Such heaters have usually
been electrical heaters which are arranged in series with the pump, the
electrical heater being connected to an appropriate source of electricity.
These heaters have heating elements which wear out and have electrical
wires which may become grounded, due to the moist condition in close
proximity to the electrical heater. Such electrical heaters are expensive
to manufacture and require careful installation by skilled mechanics in
order to protect a prospective occupant of the tub from electrical shock,
also, adequate controls must be provided for the heater to insure that the
water is not overheated by the electrical heater.
In the past, motors have been devised which serve a double function of
heating fluid and also circulating the heated fluid through a fluid
system. One such system is disclosed in the U.S. Pat. to Pezzillo No.
2,419,159, in which water is passed through a motor for heating a boiler.
The motor serves a double function of heating the fluid and also
circulating the heated fluid through the system. Apparently, in the
Pezzillo Patent, the heat is generated by the rotor of the motor.
In the U.S. Pat. to Cunningham, et al. No. 2,683,823, a motor with a jacket
around the motor is disclosed. Water is fed through this jacket for the
purpose of cooling the motor. Steam generated by the water is released
into the motor in order to provide a further cooling and then, the steam
is released to the atmosphere. U.S. Pat. to White, No. 2,127,530 discloses
a motor which has a coil for cooling the motor. The motor also has a pump
and apparently, the coil provides a cooling system for the motor. The
water for this cooling is obtained from the pump.
In the U.S. Pat. to Ahner, No. 4,500,772, a motor is disclosed which has
ducts through which cooling air is circulated over the coils and the rotor
for cooling them. The cooling fluid is then made available for heating the
passenger compartment of a vehicle.
Briefly described, the present invention includes a tub, into which is
introduced heated water from an external source. The water in the tub is
circulated from and to the tub through conduits by a centrifugal pump
which is normally disposed below the level of the water in the tub. This
centrifugal pump draws water from the bottom portion of the tub and
directs it through spaced jet nozzles disposed in the sides of the tub. An
electric motor drives the centrifugal pump and a heat exchanger
encompasses the upper portion of the body or casing of the motor. The heat
exchanger is concaved so as to overlie the convexed upper portion of the
motor and heat exchanger having a hollow interior with baffles for forming
a tortuous passageway through which the water is passed to be heated by
the heat from the motor. Water is introduced into this heat exchanger
through an intake tube, pipe or conduit connected to the high pressure
side of the pump and is discharge back into the pump through a discharge
tube, pipe or conduit connected to the low pressure side of the pump. The
two tubes, pipes or conduits which supply the water and return the water
to the pump are connected at the lowest points at opposite sides of the
curvilinear, crescent shaped heat exchanger and feed downwardly to low
positions in the pump.
Accordingly, it is an object of the present invention to provide a tub
assembly which is inexpensive to manufacture, durable in structure and
efficient in operation.
Another object of the present invention is to provide a heat exchanger for
a bath which is self draining.
Another object of the present inventon is to provide a heating system for a
bath tub which will eliminate the necessity for an electrical heater and
which will maintain the appropriate temperature of water in a tub over an
extended period of time.
Another object of the present invention is to provide a heating system for
a bath tub which is easy to install and which will readily and
inexpensively adapt a conventional pump and motor assembly so that it will
reheat the water recirculated to the tub and will also cool the electrical
motor.
Another object of the present invention is to provide a heating system for
a hot tub which has no moving parts and which can be readily and easily
adapted to a conventional motor on a tub water circulating system.
Another object of the present invention is to provide a cooling system for
a motor which drives the pump for circulating the water in the tub.
Another object of the present invention is to provide a heating system for
tub which will not readily or easily overheat.
Other objects features and advantages of the present invention will become
apparent from the following description when taken conjunction with the
accompanying drawings wherein like characters of reference designate
corresponding parts.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an exploded perspective view of the tub assembly of the present
invention, the pump thereof being connected to the nozzles and to the
drain port of a conventional tub shown in broken lines;
FIG. 2 is a side elevational view of one side of the pump, motor and heat
exchanger of the tub assembly shown in FIG. 1;
FIG. 3 is a cross-sectional view taken substantially along line 3--3 in
FIG. 2;
FIG. 4 is schematic diagram of the electric-mechanical system of the
present invention; and
FIG. 5 is a schematic perspective view of a modified heat exchanger of the
present invention.
DETAILED DESCRIPTION
Referring now in detail to the embodiments chosen for the purpose of
illustrating the present invention, numeral 10 in FIG. 1 denotes generally
a conventional tub which has an end 11 and a pair of spaced, opposed
sides, such as side 12, and a bottom 13 provided with a drain 14. Heated
water from an external source (not shown) is introduced into the tub 10
and can be drained from the tub through drain 14 when the tub 10 is no
longer in use. A primary water circulating system for the tub 10 includes
a water intake port 16 located in one of the sides 12 adjacent to the
bottom 13. A conduit, such as pipe or tube 17, leads from the water intake
or recirculator port 16 to the intake side of a centrifugal pump 18 which
is externally of tub 10. A coupling 19 on the centrifugal pump 18 secures
the pipe 17 in place.
A motor 20, externally of the tub 10, having a casing or housing 21 drives
the impeller (not shown) of the water pump 18 so that when this impeller
is rotated, water will be drawn into the low pressure or suction side 18b
of the pump 18 from pipe 17 and passed into the high pressure side 18a so
as to be discharged through a discharge spour 15 into a discharge pipe 22.
The discharge pipe 22 is secured to the spour 15 by a threaded collar 23.
The discharge pipe 22 leads to and communicates with a plurality of
discharge ports formed by jet nozzles 24 which are mounted in the sides 12
of the tub 10, these jet nozzles 24 being in spaced opposed relationship
so that streams of water emerging from the jet nozzles 24 are directed
inwardly toward a person in the tub 10. These nozzles 24 are normally
located below the waterline in the tub 10 and are above both the drain 14
and the drain port 16.
The motor 21 is electrically connected to a source of electricity by a
cable 25. Mounted on the upper convex portion of the housing, casing or
body 21 of motor 20 is a crescent shaped, semi-cylindrical heat exchanger,
denoted generally by the numeral 30. This heat exchanger 30 is formed of
sheet metal and defines a chamber into which water to be heated is
introduced. In more detail, the heat exchanger 30 includes an outer wall
31 which is convexed along its outer surface and concaved along its inner
surface. The curvature of the outer wall 31 is generally about a
horizontal axis.
Inwardly of the concaved outer wall 31 is an inner wall 32 which is spaced
inwardly of the outer wall 31 and is concentric therewith, the inner wall
32 being concaved along its lower or outer surface and convexed along its
inner surface. The ends of the walls 31 and 32 are joined by crescent
shaped end plates 33 and 34 and the bottom edges of the walls 31 and 32
are joined by rectangular bottom plates 35 and 36. These bottom plates 35
and 36 are respectively inclined in opposite directions, being inclined at
angle .alpha. with respect to a horizontal plane passing through the
longitudinal axis. This inclination of the plates 35 and 36 is from about
2.degree. to about 15.degree. to the horizontal so that the water within
the heat exchanger 30 will drain toward the ports or holes 37 and 38,
respectively. Walls 31 and 32, end plates 33 and 34, and bottom plates 35
and 36 define a closed chamber, except for the ports 37 and 38, so that
water can be introduced into the closed chamber through either port 38 or
37 and be discharged from the other port.
Within the chamber defined by the walls 31 and 32 are spaced, parallel,
baffles which are arranged either axially in radially spaced relationship
to each other or radially in axially spaced relationship to each other.
These baffles are so arranged as to provide connected successive
passageways for the travel of water through the heat exchanger 30. In one
embodiment, the baffles 40 are disposed axially so that each alternate
baffle is connected to one end plate 34 and is spaced from the other end
plate 35 and vice-versa. These baffles 40 are inclined slightly so as to
permit water to drain from the top along the connected passageways, toward
both of the bottom plates 35 and 36 and thence drain toward and out of the
ports 37 and 38, respectively.
The heat exchanger 30 subtends approximately slightly more than 180.degree.
along its inside surface of inner plate 32 and is sufficiently resilient
that it can be snapped into place over the rounded top portion of the
motor 20. Since the ends, adjacent to the ports 37 and 38 are lower than
the corners of the heat exchanger, at diagonally opposite ends of the
plates 35 and 36, the arc subtended by the plate 32, when viewed
transversely is greater than 180.degree.. Since the diameter of the plate
32 is approximately equal to the diameter of the motor housing 21, the
heat exchanger 30 can be urged or forced onto the upper exposed exterior
portion of this housing 21, the heat exchanger 30 flexing or deforming
slightly outwardly, within its elastic limits and then returning to about
its original shape as the heat exchanger 30 is fully seated on the upper
surface of the housing 21. Thus, the heat exchanger 30 will snap into
place and will not readily be removed from the motor 20. This feature also
assures that the plate 32, which is concentric with the surface of motor
21 will be seated and held in place firmly against the upper surface of
the housing 21. If desired, heat transfer mastic or adhesive can be
employed to adhere plate 32 to the housing 21. Thus, the heat exchanger 30
should be instaled prior to the time that any conduits, such as tubes 49
and 50 are installed.
Ports 37 and 38 are respectively provided with externally threaded,
downwardly protruding nipples 45 and 46 which receive the internally
threaded couplings 47 and 48 on the ends of water conduits, such as the
tubes 49 and 50, respectively. The water supply tube 49 is provided with a
second coupling 51, the coupling 51, in turn being threadedly received on
a nipple 52 which protrudes from the periphery of the high pressure side
18a of the centrifugal pump 18. Nipple 52 communicating with the interior
of the high pressure side of 18a. The tube 50 is connected to a coupling
53 which is threadedly received on a nipple 54 which communicates with the
bottom portion of the low pressure side 18b of the pump. The nipples 52
and 54 are both located toward the bottom portion of the pump 18 so that
tubes 49 and 50 provide a drop from the plates 35 and 36 for the water to
drain from both sides of the heat exchanger 30 into pump 18 whenever the
pump 18 is stopped. The nipple 52 is disposed along the periphery of the
high pressure side 18a so that the water will be pumped by the impeller
(not shown) of the centrifugal pump 18 up through the tube 49 to fill the
heat exchanger 30 and thence pass downwardly through the tube 50, to
return to the low pressure or suction side 18b of the pump 18 for
recirculation to the high pressure side 18a.
The motor 30 normally heats to about 170.degree. F. to about 180.degree. F.
during operation and thus generates heat which will be transferred by
conduction via housing 21 through the plate 32 to heat the water in the
heat exchanger 30. Since the tube 49 is connected to the high pressure
side 18a of the centrifugal pump 18, water will be delivered through this
tube 49 into the heat exchanger 30 and thence into the tube 50 and back to
the low pressure side 18b of the heat exchanger 18 whenever the motor 20
and its pump 18 are operated. This circulation of the water is automatic.
Furthermore, whenever the pump 18 is shut down, the water will tend to
drain from the heat exchanger 30 and pump 18, through the pipe 17 back
into the tub 10, passing through port 16. Thus, there will be no
appreciable water in the heat exchanger 30 when the pump 18 is not in
operation. This is a desirable feature since it will assure that the
relatively warm heat exchanger 30 will not appreciably promote the growth
of bacteria and slime in the heat exchanger.
The baffles 40 will create a tortuous passageway for the water back and
forth through the heat exchanger 30 when the pump 18 is operating. This
will assure that there is adequate area to area contact between the water
and the heat exchanger body so that there is a substantial transfer of
heat from the motor 20 to the heat exchanger 30. This transfer of heat is
sufficient, as a general rule, to maintain the temperature of the water in
the hot tub at an appropriate level such as approximately 104.degree..
It may be desirable, however, to provide a timer, such as timer 60 seen in
FIG. 4. This time 60 should be installed in a series, in a circuit 61 of
from a osurce of electricity to the control means, such as a guillotine
type solenoid valve 62, in either the intake tube 49 or the return tube
50. This solenoid valve 62 is opened and closed or partially closed by
circuit 62 which includes a thermostat 63 so that when the water is heated
sufficiently, the solenoid valve 70 will be closed or partially closed to
prevent or retard the circulation of water to the heat exchanger 30 until
the temperature of the tub 10 has dropped. Timer 60 is manually set and
will determine when the valve 70 is operative.
In the modified embodiment illustrated in FIG. 5, the motor 120 is provided
with heat exchanger 130 received on the arcuate upper surface of the
motor. Motor 120 drives the pump 118 for circulating water to a tub in
manner identical to the circulation of the water by pump 18. According to
the present embodiment, the heat exchanger 130 has a flat outer wall 131
but an arcuate inner wall 132 which fits and is concentric with the upper
surface of the housing of motor 120. In this embodiment, the bottom plates
such as plate 135 are inclined toward their conduit or tube such as tube
149 so that the heat exchanger 130 will drain in a manner described for
heat exchanger 30. This heat exchanger 130 has end plates 133 and 134 as
well as side plates such as plate 138. The plates 131, 132, 133, 134, 135
and 138 define a closed chamber within which are disposed a plurality of
radially extending longitudinally spaced baffles 141 which have drain
holes 142. The baffles 141 form a passageway from tube 149 so as to pass
the water successively over the top portion of motor 120 and discharge the
water as illustrated for the heat exchanger 30.
It will be obvious to those skilled in the art that many variations may be
mde in the embodiment here chosen for the purpose of illustrating the
present invention without departing from the scope thereof as defined by
the appended claims.
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