U.S. patent application number 12/576830 was filed with the patent office on 2010-02-04 for submersible pump with integrated liquid level sensing and control system.
This patent application is currently assigned to Johnson Pump of America. Invention is credited to Gerald A. Assessor, Michael Collins.
Application Number | 20100028166 12/576830 |
Document ID | / |
Family ID | 37527784 |
Filed Date | 2010-02-04 |
United States Patent
Application |
20100028166 |
Kind Code |
A1 |
Collins; Michael ; et
al. |
February 4, 2010 |
SUBMERSIBLE PUMP WITH INTEGRATED LIQUID LEVEL SENSING AND CONTROL
SYSTEM
Abstract
In accordance with one embodiment of the present invention,
there is provided a submersible pump that includes a pump housing
forming a main compartment for receiving a pump impeller and having
liquid entrance and exit openings in said main compartment, and an
impeller mounted in the main compartment. The pump housing is
adapted for submersion in a body of liquid whose level is to be
controlled, and a sealed auxiliary compartment is formed as an
integral part of the housing and located to be at least partially
submerged in the liquid body. A drive motor is coupled to the
impeller for rotating the impeller to eject liquid from the main
compartment through the exit opening. An electric-field sensor is
mounted in the sealed auxiliary compartment for detecting the
elevation of the surface of the liquid body adjacent the sealed
auxiliary compartment. At least one controllable switch is
connected in the power supply line for controlling the supply of
power to the drive motor, and the electric-field sensor is
connected to the controllable switch for opening and closing the
switch in response to changes in the detected elevation of the
surface of the liquid body adjacent the outer surface of the sealed
auxiliary compartment.
Inventors: |
Collins; Michael;
(DesPlaines, IL) ; Assessor; Gerald A.; (St.
Charles, IL) |
Correspondence
Address: |
NIXON PEABODY LLP
300 S. Riverside Plaza, 16th Floor
CHICAGO
IL
60606
US
|
Assignee: |
Johnson Pump of America
Schiller Park
IL
|
Family ID: |
37527784 |
Appl. No.: |
12/576830 |
Filed: |
October 9, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
11210340 |
Aug 24, 2005 |
7625187 |
|
|
12576830 |
|
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Current U.S.
Class: |
417/44.1 |
Current CPC
Class: |
F04D 15/0218
20130101 |
Class at
Publication: |
417/44.1 |
International
Class: |
F04D 15/00 20060101
F04D015/00; F04D 13/08 20060101 F04D013/08 |
Claims
1. A submersible pump comprising: a pump body forming a main
compartment having liquid intake and discharge openings, wherein
said pump body is configured to be at least partially submerged in
a body of liquid whose level is to be controlled; a drive motor
housed in said main compartment; an impeller coupled to said drive
motor to selectively eject liquid through said discharge opening
when said impeller is rotated by said drive motor; a sealed
liquid-tight auxiliary compartment formed as an integral part of
said pump body and located to be at least partially submerged in
said liquid body; at least one electric-field sensor mounted on a
circuit board, said circuit board being enclosed entirely within
said sealed auxiliary compartment and attached to an inner surface
of an outer wall of said sealed auxiliary compartment, said circuit
board being configured to produce an electric field that extends
through said outer wall into space adjacent the outer surface of
said outer wall and thereby detect changes in the electric field of
said sensor caused by a change in elevation of the surface of said
liquid body adjacent a portion of the outer surface of said sealed
auxiliary compartment directly adjacent said sensor; a pair of
electrical conductors coupling said electric-field sensor and said
drive motor to a power supply; and a controllable switch coupled to
at least one of said pair of electrical conductors and configured
to control the supply of electrical power to said drive motor, said
electric-field sensor being connected to said controllable switch
to turn said drive motor on and off in response to changes in the
detected elevation of the surface of said liquid body adjacent the
outer surface of said sealed auxiliary compartment.
2. The submersible pump of claim 1, wherein said at least one
electric-field sensor comprises upper and lower electric-field
sensors located at different elevations with respect to said pump
body, the upper electric-field sensor producing a signal for
turning said drive motor on after the surface of said liquid body
rises to a first predetermined elevation, and the lower
electric-field sensor producing a signal for turning said drive
motor off when the surface of said liquid body drops to a second
predetermined elevation.
3. The submersible pump of claim 2, wherein said second
predetermined elevation is less than about 0.7 inch (1.8 cm) above
the lowermost surface of said pump.
4. The submersible pump of claim 1, further comprising a manual
override switch connecting said drive motor directly to the power
supply, bypassing said controllable switch.
5. The submersible pump of claim 1, further comprising a detachable
volute attachable to the lower end of said main compartment to
facilitate access to said impeller.
6. The submersible pump of claim 5, further comprising mechanical
connectors formed as integral parts of said pump body and said
volute for detachably attaching said volute to said pump body, said
connectors including cam surfaces for drawing said volute tightly
against said pump body as said volute is attached to said pump
body.
7. The submersible pump of claim 6, wherein said connectors are
flanged tabs extending upwardly from the top edge of said volute,
and cooperating lugs on said pump body for engaging said flanged
tabs as said volute is rotated relative to said pump body, at least
one of the engaging surfaces of said flanged tabs and lugs forming
said cam surfaces.
8. The submersible pump of claim 7, wherein said drive motor is
contained in a motor housing surrounded by an O-ring that engages
an opposed surface of said main compartment to form a liquid-tight
seal between upper and lower regions of said main compartment.
9. The submersible pump of claim 8, wherein said upper portion of
said main compartment above said O-ring is sealed against the entry
of liquid.
10. The submersible pump of claim 1, further comprising a strainer
detachably attached to the lower end of said pump body, wherein
said strainer is configured to prevent solid material of a
predetermined size from entering said main compartment.
11. The submersible pump of claim 10, wherein the lower portion of
said strainer is tapered inwardly to reduce the footprint of said
strainer.
12. The submersible pump of claim 2, wherein said electric-field
sensors are mounted on a printed circuit board attached to the
inside surface of an outer wall of said auxiliary compartment.
13. The submersible pump of claim 12, wherein at least one of said
pair of electrical conductors passes through a sealed aperture in a
wall of said auxiliary compartment and is electrically connected to
a conductor on said printed circuit board.
14. The submersible pump of claim 12, wherein said controllable
switch is mounted on said printed circuit board, wherein electrical
conductors connect said controllable switch to the upper end of
said drive motor.
15. The submersible pump of claim 1, further comprising a spout
extending outwardly from said discharge opening, and a check valve
mounted on said spout.
16. A method of pumping liquid from a liquid body with a pump, the
method comprising: placing a pump body in said body of liquid whose
level is to be controlled, said pump body forming a main
compartment defining liquid intake and discharge openings, said
main compartment containing a drive motor operatively connected to
an impeller and configured to eject liquid from said body of liquid
outwardly through said discharge opening by selectively rotating
said impeller; detecting the elevation of the surface of said
liquid body with at least one electric-field sensor mounted on a
circuit board, said circuit board being enclosed entirely within a
sealed liquid-tight auxiliary compartment formed as an integral
part of said pump body and located to be at least partially
submerged in said liquid body, said circuit board being attached to
an inner surface of an outer wall of said sealed auxiliary
compartment to produce an electric field that extends through said
outer wall into space adjacent the outer surface of said outer wall
so that the electric field of said at least one electric-field
sensor is altered by the presence or absence of liquid adjacent a
portion of the outer surface of said outer wall of said auxiliary
compartment adjacent said at least one electric-field sensor and
thereby producing an output signal that changes with the presence
or absence of liquid along the outer surface of said auxiliary
compartment adjacent said at least one electric-field sensor; and
controlling the supply of electrical power to said drive motor in
response to changes in said output signal from said at least one
electric-field sensor.
17. The method of claim 16, wherein said at least one
electric-field sensor includes upper and lower electric-field
sensors respectively located at first and second predetermined
elevations, said upper sensor producing an on signal turning said
drive motor on when the surface of said liquid body rises to said
first predetermined elevation, and said lower sensor producing an
off signal turning said drive motor off when the surface of said
liquid body drops to said second predetermined elevation.
18. The method of claim 17, wherein the turning on of said drive
motor is delayed by a predetermined delay interval following the
detection of the rising of the surface of said liquid body to said
first predetermined elevation.
19. A method of pumping liquid from a liquid body with a pump at
least partially disposed in said liquid body whose level is to be
controlled, the method comprising placing a pump body in said body
of liquid, said pump body forming a main compartment defining
liquid intake and discharge openings, said main compartment
containing a drive motor connected to an impeller and configured to
eject liquid from said body of liquid outwardly through said
discharge opening by selectively rotating said impeller; detecting
the elevation of the surface of said liquid body with at least one
electric-field sensor mounted on a circuit board, said circuit
board being enclosed entirely within a sealed liquid-tight
auxiliary compartment formed as an integral part of said pump body
and located to be at least partially submerged in said liquid body,
said circuit board being attached to an inner surface of an outer
wall of said sealed auxiliary compartment such that said at least
one electric-field sensor senses a difference in a dielectric
constant in the space adjacent the outer surface of said outer wall
due to the presence or absence of liquid adjacent a portion of the
outer surface of said outer wall of said auxiliary compartment
adjacent said at least one electric-field sensor and thereby
producing an output signal that changes with the presence or
absence of liquid along the outer surface of said auxiliary
compartment adjacent said at least one electric-field sensor; and
controlling the supply of electrical power to said drive motor in
response to changes in said output signal from said at least one
electric-field sensor to trigger a pump to begin pumping said
liquid.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application is a divisional of U.S. patent application
Ser. No. 11/210,340, filed Aug. 24, 2005, titled "Submersible Pump
with Integrated Liquid Level Sensing and Control System," which is
hereby incorporated by reference in its entirety and from which
priority is claimed.
FIELD OF THE INVENTION
[0002] The present invention relates generally to submersible pumps
and, more particularly, to submersible pumps having integrated
liquid-level sensing and control systems.
SUMMARY OF THE INVENTION
[0003] In accordance with one embodiment of the present invention,
there is provided a submersible pump that includes a pump body
forming a main compartment for receiving a drive motor and having
liquid intake and discharge openings. The pump body is adapted for
submersion in a body of liquid whose level is to be controlled, and
a sealed auxiliary compartment is formed as an integral part of the
housing and located to be at least partially submerged in the
liquid body. The drive motor is coupled to an impeller for ejecting
liquid from the main compartment through the exit opening. An
electric-field sensor is mounted in the sealed auxiliary
compartment for detecting the elevation of the surface of the
liquid body adjacent the sealed auxiliary compartment. A
controllable switch is coupled to a pair of electrical conductors
for coupling the electric-field sensor and drive motor to a power
supply. The controllable switch controls the supply of electrical
power to the drive motor, and the electric-field sensor is
connected to the controllable switch for turning the drive motor on
and off in response to changes in the detected elevation of the
surface of said liquid body adjacent the outer surface of said
sealed auxiliary compartment.
[0004] One particular embodiment includes a pair of electric-field
sensors located at different elevations. The upper sensor produces
a signal that turns the drive motor on after the surface of the
liquid body rises to a first predetermined elevation, and the lower
sensor produces a signal that turns the drive motor off after the
surface of the liquid body drops to a second predetermined
elevation. The turning on of the drive motor is preferably delayed
by a predetermined delay interval following the detection of the
rising of the surface of the liquid body to the first predetermined
elevation.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] While the invention is susceptible to various modifications
and alternative forms, specific embodiments have been shown by way
of example in the drawings and will be described in detail herein.
It should be understood, however, that the invention is not
intended to be limited to the particular forms disclosed. Rather,
the invention is to cover all modifications, equivalents, and
alternatives falling within the spirit and scope of the invention
as defined by the appended claims.
[0006] FIG. 1 is a bottom perspective from one side of one
embodiment of a submersible pump embodying the invention.
[0007] FIG. 2 is a bottom perspective from the opposite side of the
pump of FIG. 1.
[0008] FIG. 3 is a top perspective of the pump of FIG. 1 from the
same side shown in FIG. 1.
[0009] FIG. 4 is an exploded perspective of the pump of FIG. 1.
[0010] FIG. 5 is a bottom perspective of the strainer in the pump
of FIG. 1.
[0011] FIG. 6 is a bottom perspective of an alternative strainer
for use in the pump of FIG. 1.
[0012] FIG. 7 is a diagrammatic plan view of the body of the pump
of FIG. 1.
[0013] FIG. 8 is a section taken along line 8-8 in FIG. 7.
[0014] FIG. 9 is a section taken along line 9-9 in FIG. 7.
[0015] FIG. 10 is the same section shown in FIG. 8 with all the
parts of the pump assembled in the body.
[0016] FIG. 11 is the same section shown in FIG. 9 with all the
parts of the pump assembled in the body.
[0017] FIG. 12 is an enlarged side elevation of the pump of FIG. 1
partially submerged in a body of liquid.
[0018] FIG. 13 is the same side elevation shown in FIG. 12 showing
a reduced body of liquid.
[0019] FIG. 14 is a schematic diagram of the electrical system
included in the pump of FIG. 1.
[0020] FIG. 15 is an exploded perspective of the discharge spout of
the pump of FIG. 1 with a check valve to be attached to the
spout.
[0021] FIG. 16 is an exploded perspective of a modified discharge
spout and check valve.
[0022] FIG. 17 is an enlarged side elevation of the printed circuit
board installed in the pump of FIG. 1.
[0023] FIG. 18 is an enlarged top plan view of the pump of FIG. 1
with the top cover plate removed.
DETAILED DESCRIPTION OF ILLUSTRATED EMBODIMENTS
[0024] Although the invention will be described in connection with
certain preferred embodiments, it will be understood that the
invention is not limited to those particular embodiments. On the
contrary, the invention is intended to cover all alternatives,
modifications, and equivalent arrangements as may be included
within the spirit and scope of the invention as defined by the
appended claims.
[0025] Turning now to the drawings and referring initially to FIG.
1, a submersible pump 10 includes a body 11 forming a main
compartment 12 for receiving a drive motor 13. The lower portion of
the motor 13 is encased in a liquid-impervious housing 14. The
output shaft of the motor 13 extends downwardly through a sealed
aperture in the bottom wall of the housing 14 and is attached to an
impeller 15. The pump body 11 also forms an integral auxiliary
compartment 16 for receiving electrical sensing, switching and
control components.
[0026] The main compartment 12 is divided into upper and lower
regions 17 and 18 (see FIGS. 8 and 9) by an annular wall 19 formed
as an integral part of the pump body 11. The lower region 18 in
turn is partitioned into inner and outer regions 20 and 21 by an
inner cylinder 22 extending downwardly from the inner edge of the
wall 19. The motor housing 14 extends downwardly through the inner
region 20 so that the impeller 15 is positioned inside a volute 23
attached to the lower end of the cylinder 22. When the pump is
submerged in a body of liquid to be pumped, the liquid enters a
cavity 24 between the impeller 15 and the volute 23 through a
central aperture 25 in the bottom wall of the volute. Then when the
impeller 15 is driven by the motor 13, the liquid in the cavity 24
is driven upwardly along the inside wall 26 of the volute into an
annular portion of the inner region 20 between the cylinder 22 and
the motor housing 14, and then outwardly through a discharge port
28 in the cylinder 22. The discharge port 28 is the opening into a
conduit 29 formed as an integral part of the pump body 11. The
conduit 29 extends through the annular region 21 and terminates in
an outwardly extending spout 30.
[0027] The upper end of the cavity 27 is closed by a flange 31
extending outwardly from the motor housing 14, and is sealed by an
O-ring 32 mounted in a groove in the outer surface of the motor
housing 14 above the flange 31. The O-ring 32 is formed of a
resilient material and is dimensioned to press against a step in
the inside surface of the cylinder 22, thereby forming a tight seal
between the opposed walls of the cylinder 22 and the motor housing
14. This seal prevents any liquid from entering the upper region 17
of the main compartment 12, where the electrical connections to the
drive motor are located. After the drive motor 13 has been
installed, the open upper end of the compartment 12 is closed by
attaching a top plate 12a that is sealed (e.g., by ultrasonic
bonding) to the lip of the open upper end of the compartment 12 to
form a liquid-tight seal.
[0028] To facilitate access to the impeller 15, e.g., for cleaning
or maintenance purposes, the volute 23 is detachably attached to
the lower end of the cylinder 22. Specifically, the volute 23 has
multiple flanged tabs 35 extending upwardly from the top edge of
the volute 23 for engaging cooperating lugs 36 (see FIGS. 8 and 9)
on the inside wall of the cylinder 22. When the volute 23 is
rotated relative to the cylinder 22, the bottom surfaces of the
flanges on the upper ends of the tabs 35 slide over the top
surfaces of the lugs 36, which slope upwardly to form cam surfaces
that draw the volute 23 upwardly against the cylinder 22.
[0029] Attached to the bottom of the pump body 11 is a strainer 37
through which liquid must pass to enter the volute 23. The strainer
37 includes multiple openings 38 that allow liquid to pass through
the strainer while screening out solid material of a size larger
than the openings 38. The strainer 37 is connected to the pump body
11 by a pair of flanged tabs 39 extending upwardly from the top
edge of the strainer 37 and fitting into complementary apertures 40
in the outer wall of the pump body 11. The tabs 39 are resilient to
allow them to flex laterally and slide along the outer surface of
the pump body 11 as the strainer 37 is urged upwardly toward the
bottom of the pump body 11. When the lower edges of the flanges 39a
on the tabs 39 pass the lower edges of the apertures 40, the
flanges 39 snap into the apertures 40, locking the strainer 37 in
place on the pump body 11. To detach the strainer, the flanges 39
are simply pushed inwardly while urging the strainer 37 downwardly
to move the lower edges of the flanges 39a below the lower edges of
the apertures 40.
[0030] The strainer 37 has multiple holes 41 for receiving mounting
screws 41a for attaching the pump to a suitable mounting surface
42. When the pump is installed in the bilge of a boat, for example,
the mounting surface 42 is typically the surface of a board
provided on the floor of the bilge to avoid any danger of
penetration of the hull of the boat by the mounting screws. Each of
the holes 41 is surrounded by a boss on the exterior surface of the
bottom of the strainer 37.
[0031] FIG. 6 illustrates an alternative strainer 43 that is taller
than the strainer 37. The lower portion 44 of this alternative
strainer 43 is tapered inwardly to reduce the size of the footprint
of the strainer, to facilitate mounting of the pump in cramped
spaces.
[0032] In the illustrative pump, the electric-field sensors and the
drive motor are connected to a power supply (e.g., the battery B in
FIG. 14) by three insulated wires 50, 51 and 52 and various
components mounted on a printed circuit board 53 located in the
auxiliary compartment 16. The auxiliary compartment 16 is totally
enclosed except for two wiring apertures 54 and 55 and an open
lower end through which the circuit board 53 is installed in the
compartment. The circuit board 53 is coated with adhesive on its
outer surface so that it can simply be adhered to the inside
surface of the exterior wall of the auxiliary compartment 16. After
the circuit board 53 has been installed, the open lower end of the
compartment 16 is closed by attaching a bottom plate 56 that is
sealed (e.g., by ultrasonic bonding) to the lip of the open end of
the auxiliary compartment 16 to form a liquid-tight seal. A grommet
57 seals the external wiring aperture 54 so that liquid cannot
enter the compartment 16 through this opening.
[0033] As can be seen in the electrical schematic diagram in FIG.
14, the wire 50 is connected from the positive terminal of the
power supply, presented in an exemplary embodiment as battery B, to
a contact 58 (also referred to herein as "conductor") on the
printed circuit board 53 to supply power to a controllable
solid-state switch 60 (e.g., a field-effect transistor). A second
wire 50a connects the other side of the switch 60, e.g., via an
electrical coupling to contact/conductor 59 on the circuit board
53, to the positive terminal of the drive motor 13, so that the
state of the switch 60 controls the supply of electrical power to
the drive motor 13.
[0034] The state of the switch 60 is controlled by the output
signals from two electric-field sensors 61 and 62. Specifically,
the switch 60 turns the drive motor 13 on and off in response to
changes in the detected elevation of the surface of the liquid body
adjacent the outer surface of the sealed auxiliary compartment 16.
The upper sensor 61 produces a signal that turns the drive motor 13
on after the surface of the liquid body rises to a first
predetermined elevation (e.g., 2 inches above the bottom of the
strainer 37), and the lower sensor 62 produces a signal that turns
the drive motor off when the surface of said liquid body drops to a
second predetermined elevation (e.g., 0.6 inch above the bottom of
the strainer 37).
[0035] As can be seen in FIGS. 10-13 and 17, the printed circuit
board 53 attached to the inside surface of the side wall 63 of the
auxiliary compartment 16 so that the electric fields of the sensors
61 and 62 are altered by the presence or absence of water or other
liquid along the portions of the outer surface of the wall 63 that
are directly adjacent the sensors. The electric-field sensors 61
and 62 are preferably of the type described in U.S. Pat. Nos.
6,320,282, 6,310,611 and 5,594,222 assigned to TouchSensor
Technologies, LLC and Integrated Controls. Circuit boards
containing such sensors are available from TouchSensor
Technologies, LLC. For example, circuit board Part No.
000600384-01, modified to convert from stuttering operation to
continuous operation, is suitable for use as the circuit board 53
in the illustrative embodiment of the present invention.
[0036] The electric-field sensors 61 and 62 are located at
different elevations (see FIGS. 10-13 and 17). The upper sensor 61
produces a signal that renders the switch 60 conductive to energize
the drive motor 13 by connecting it to a battery B when the surface
of the liquid body rises to the first predetermined elevation,
illustrated in FIG. 10, and the lower sensor 62 produces a signal
that renders the switch non-conductive to de-energize the drive
motor 13 by disconnecting it from the battery B when the surface of
said liquid body drops to the second predetermined elevation,
illustrated in FIG. 11. The wire 50a from the switch 60 and wire 51
from the negative terminal of the battery B are connected to the
power-input terminals 13a and 13b of the motor 13 at the upper end
of the motor 13 in the liquid-tight upper end of the main
compartment 12 (see FIG. 18). The wire 50a passes through the
aperture 55 near the top of the wall that divides the main and
auxiliary compartments 12 and 16. The third wire 52 is spliced to
the wire 50a and passes out through the grommet 57 for connection
to a manual override switch described below. A capacitor C is
connected across the terminals of the drive motor 13 to suppress
spurious high-frequency signals produced during operation of the
motor.
[0037] As depicted in FIG. 10, when the liquid level 64 of a liquid
body 65 rises to the elevation of the upper sensor 61, the output
signal from this sensor changes. This change in the output signal
activates a time delay circuit 66 which renders the switch 60
conductive if the change in the sensor output signal persists for a
preselected time interval (e.g., 3 to 4 seconds) determined by the
delay circuit 66. The delay prevents undesired activation of the
switch 60 and drive motor 13 in response to intermittent changes in
the elevation of the liquid level caused by, for example, sloshing
of the liquid body (such as occurs in a boat bilge when the boat
bounces or changes speed). When the change in the sensor output
signal persists for the prescribed delay interval, the switch 60 is
rendered conductive to turn on the drive motor 13, which in turn
rotates the impeller 15 to expel liquid from the bilge or other
container for the liquid body 65.
[0038] As liquid is expelled by the pump, the liquid level 64
drops, eventually dropping to the level of the lower sensor 62 (see
FIG. 11). The removal of liquid from that portion of the outer
surface of the wall 63 adjacent the lower sensor 62 causes a change
in the output signal of that sensor, which is used to render the
switch 60 non-conductive and thereby turn off the motor 13. The
lower sensor 62 is preferably located at an elevation that causes
the motor 13 to be turned off at a liquid level about 0.6 inch
above the bottom surface of the strainer 37, which is sufficient to
avoid any danger of cavitation of the pump. One of the advantages
of the electric-field sensors is that they allow the liquid level
to be pumped down to a level relatively close to the lowermost
surface of the pump. In addition, the sensors and the circuitry to
which they are connected can be tested without the use of a body of
liquid, by simply placing a human finger where the liquid level
should be to change the output signals of the sensors (the water in
the human finger affects the electric fields of the sensors in the
same way as a body of water).
[0039] To permit the drive motor 13 to be turned on and off
manually, independently of the switch controlled by the signals
from the sensors 61 and 62, a manual override switch 67 is
connected between the positive terminal of the battery B and the
corresponding terminal of the drive motor 13. This override switch
67 is shown in the electrical schematic diagram in FIG. 14. When
the override switch 67 is closed, power from the battery B is
supplied directly to the drive motor 13 to turn the drive motor on.
Opening the switch 67 turns the motor 13 off.
[0040] In the illustrated pump, the end portion of the discharge
spout 30 is threaded on its outer surface for receiving a check
valve of the type illustrated in FIG. 15. A resilient valve element
70 is seated against the end of the spout 30, inside a telescoping
outer tube 71. An internally threaded sleeve 72 is threaded onto
the spout 30 so that a flange 73 on the outer end of the sleeve 72
presses the tube 71 against a flange 74 at the base of the valve
element 70 to capture both the valve element 70 and the tube 71 and
hold them in place against the end of the spout 30. When the pump
is operating, the pressure generated by the pump forces the valve
element 70 to open to allow the liquid expelled by the pump to exit
the spout 30. When the pump ceases operation, the valve element 70
closes and cannot be opened by any liquid pressure applied from
outside the pump.
[0041] In an alternative embodiment illustrated in FIG. 16, an
enlarged spout 80 is internally threaded to receive an externally
threaded sleeve 81. A metal washer 82 and a resilient valve element
83 are captured between the end of the sleeve 81 and a shoulder 84
formed in the interior wall of the spout 80. When the pump is
operating, the pressure generated by the pump forces the valve
element 83 to open to allow the liquid expelled by the pump to exit
the spout 80. When the pump ceases operation, the valve element 83
closes and cannot be opened by any liquid pressure applied from
outside the pump.
[0042] While particular embodiments and applications of the present
invention have been illustrated and described, it is to be
understood that the invention is not limited to the precise
construction and compositions disclosed herein, and that various
modifications, changes, and variations may be apparent from the
foregoing descriptions without departing from the spirit and scope
of the invention as defined in the appended claims.
* * * * *