U.S. patent number 3,741,675 [Application Number 05/117,392] was granted by the patent office on 1973-06-26 for self-priming centrifugal pump with automatic air release valve.
This patent grant is currently assigned to The Gorman-Rupp Company. Invention is credited to Stanley B. McFarlin, Robert J. Porter.
United States Patent |
3,741,675 |
Porter , et al. |
June 26, 1973 |
SELF-PRIMING CENTRIFUGAL PUMP WITH AUTOMATIC AIR RELEASE VALVE
Abstract
An automatic air release valve is connected to the discharge
side of a self-priming centrifugal pump for venting air from the
pumping system during the priming cycle. The valve automatically
closes upon completion of the priming cycle to prevent venting of
liquid during the pumping cycle. A flow responsive actuator
maintains the valve closed.
Inventors: |
Porter; Robert J. (Mansfield,
OH), McFarlin; Stanley B. (Jeromesville, OH) |
Assignee: |
The Gorman-Rupp Company
(Mansfield, OH)
|
Family
ID: |
26815239 |
Appl.
No.: |
05/117,392 |
Filed: |
February 22, 1971 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
|
773549 |
Nov 5, 1968 |
3575521 |
|
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Current U.S.
Class: |
415/11; 415/27;
137/115.06 |
Current CPC
Class: |
F04D
9/006 (20130101); Y10T 137/2587 (20150401) |
Current International
Class: |
F04D
9/00 (20060101); F04d 009/00 (); F04d 027/02 () |
Field of
Search: |
;415/11,27,26
;137/117,119 ;251/140,141 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Raduazo; Henry F.
Parent Case Text
CROSS REFERENCED PATENT
This is a continuation-in-part of United States patent application
Ser. No. 773,549 filed Nov. 5, 1968 by Robert J. Porter and Stanley
B. McFarlin entitled SELF-PRIMING CENTRIFUGAL PUMP WITH AUTOMATIC
AIR RELEASE VALVE, now U.S. Pat. No. 3,575,521.
Claims
We claim:
1. In combination with a pump having inlet means and outlet means,
an air release valve assembly comprising:
a. a chamber;
b. said chamber having an outlet port;
c. chamber inlet means communicating said chamber with said pump
outlet means;
d. valving means including;
1. a valve seat in said chamber surrounding said outlet port;
2. a valve member movably supported in said chamber; and,
3. biasing means urging said valve member toward an open position
spaced from said seat;
e. said valving means having a closed position wherein said valve
member is in engagement with said seat to block fluid flow through
said outlet port;
f. said chamber inlet means directing pump effluent into said
chamber along a flow path for impingement on said valve member to
create a pressure force on said valve member urging said valve
member toward said closed position; and,
g. actuator means associated with said valve member for moving said
valve member to said closed position in response to liquid flow
conditions through said pump outlet means.
2. A pump as claimed in claim 1 wherein said actuator means
comprises an electrically energized actuator element, a control
switch in circuit relation with said actuator element, and means
for actuating said control switch in response to flow conditions in
said pump outlet means.
3. A pump as claimed in claim 2 wherein said pump outlet means
includes a check valve having means movable between open and closed
positions, said control switch being operated in response to
movement of said check valve means.
4. The pump claimed in claim 2 wherein said means for actuating
said control switch includes a member which is movable in
proportion to pressure of liquid in said pump outlet means.
5. In combination:
a. pump means operable through a priming cycle and a pumping cycle,
said pump means including an inlet opening and an outlet
opening;
b. discharge valve means connected to said outlet opening for
permitting fluid flow therethrough during said pumping cycle and
for blocking fluid flow therethrough during said priming cycle;
c. air release valve means connected between said pump outlet
opening and said discharge valve means for permitting fluid flow
therethrough during said priming cycle and blocking fluid flow
therethrough during said pumping cycle, said air release valve
means comprising;
1. a valve housing defining a vortex chamber having a cylindrical
chamber wall portion;
2. means defining a valve inlet opening for directing pump effluent
into said chamber substantially tangentially along said wall
portion to create vorticular flow in said chamber;
3. an axial valve outlet opening from said chamber;
4. a valve seat surrounding said valve chamber;
5. a valving member supported by said housing for movement toward
and away from said valve seat, said valving member being biased
away from said seat and including a surface portion impinged upon
by vorticular flow of pump effluent in said chamber which moves
said valving member toward said valve seat; and,
d. an actuator for urging said valving member toward engagement
with said seat in response to sensed pump outlet liquid conditions
whereby when said pump means is primed said air release valve is
maintained closed.
6. The combination claimed in claim 5 wherein said discharge valve
means comprises a check valve member which opens only during said
pumping cycle, and means for operating said actuator means in
response to movement of said check valve member toward an open
position.
7. The combination claimed in claim 6 wherein said actuator means
is electrically energized through a control circuit and said means
for operating said actuator means comprises a control switch
actuated by movement of a part connected to said check valve member
away from a position corresponding to the closed position of said
check valve member.
8. The combination claimed in claim 7 wherein said discharge valve
means further comprises a pivot shaft supporting said check valve
member for pivotal movement between its open and closed positions,
said switch actuating part connected to said pivot shaft for
movement therewith.
9. The combination claimed in claim 8 wherein said control switch
comprises a mercury switch and said part comprises a bracket
supporting said mercury switch for tipping movement relative to
horizontal when said pivot shaft rotates.
10. The combination claimed in claim 7 wherein said discharge valve
means further comprises a pivot shaft supporting said check valve
member for pivotal movement, said switch actuating part connected
to said pivot shaft and movable therewith to engage a switch
operating lever when said valve member has moved a predetermined
amount away from said closed position.
11. The combination claimed in claim 5 further including control
means for operating said actuator, said control means comprising at
least one control member which is movable in response to changes in
pressure of liquid in the vicinity of said pump outlet opening.
Description
BACKGROUND OF THE INVENTION
The present invention relates generally to the centrifugal pump
art, and more particularly to pumping systems including a
self-priming centrifugal pump and an automatic air release valve
connected to the discharge side of the pump for venting air from
the system during the priming cycle.
During the priming cycle of a centrifugal self-priming pump, the
air or gas in the pump suction line is evacuated to provide the
suction lift. In so-called force main systems in which a head of
liquid is maintained in the discharge line downstream from the
pump, suitable provision must be made for venting such air or gas
from the pumping system.
It has been conventional to provide centrifugal pumping systems
with a constantly open vent communicating with the discharge side
of the pump. One typical vent structure which has been used is a
flow restrictor device comprising a closed cylindrical housing
having a tangential inlet communicating with the pump discharge
line and an axial outlet communicating with a sump or a return line
or the like.
The gas or air evacuated from the pump suction lines during the
priming cycle is vented through the flow restrictor together with a
portion of the liquid which is forced from the discharge chamber of
the pump. After the pump has been fully primed pumped liquid flows
through the flow restrictor during the entire time that the pump is
in operation.
The flow restrictor of the prior art is constructed to minimize the
flow of liquid therethrough during the pumping cycle. Nevertheless,
the constant venting of a portion of the liquid being pumped
through the flow restrictor is both wasteful and expensive and
decreases the efficiency of the pump.
Another disadvantage of many of the prior art vent arrangements is
that they are subject to malfunction under conditions which may
result in clogging of the vent lines. Centrifugal pumps are often
used to handle liquids containing heavy concentrations of foreign
materials or solids which tend to clog the vent lines and the flow
restrictor itself and thereby prolong or even prevent priming.
Furthermore, the closed housing of the conventional flow restrictor
device described above is difficult to clean and is responsible for
increased costs.
SUMMARY OF THE INVENTION
The present invention provides a new and improved air venting valve
for a self-priming pumping system in which a flow actuated vent
valving member is moved toward a position in which venting
terminates by fluid flow in the system and wherein a flow
responsive actuator complements operation of the valving member to
assure that the valving member closes completely when the pump is
primed.
The new air release valve is associated with the discharge side of
a centrifugal pump for encouraging pump priming while minimizing
inefficiencies connected with continuously venting systems. The
valve is open during the priming cycle to vent the air or gas
evacuated from the pump suction lines and automatically closes when
the pump is fully primed. This avoids venting liquid during the
pumping cycle.
The air release valve is responsive to the conditions of fluid flow
through it so that the valve remains open so long as pumped fluid
flow is below a given level. When the pump output flow rate reaches
a predetermined level, indicating the pump is primed, the valve
closes.
The air release valve comprises a housing which defines a vortex
chamber having a tangential inlet and a relatively larger axial
outlet. A valving member is mounted in the housing and is biased to
a normally open position permitting flows of gas or mixtures of gas
and liquid through the valve. The valving member is movable from
its open position to a closed position in response to liquid
flow.
The valving member is preferably biased to its open position by a
spring. The biasing spring force acting on the valving member is
adjustable so that the valving member closes at a particular
condition point of the pumping system; that is, the point at which
the pump commences to pump liquid at the rated capacity and
head.
When a pumping cycle is completed and the pump is shut off, the
valve is automatically opened by the biasing spring force. If for
any reason the suction head is lost before the next pumping cycle,
the valve remains open upon reactuation of the pump until a full
prime is attained, whereupon the valve again automatically closes.
If pump suction head is not lost, the valve closes immediately when
the pump is started.
The biasing spring force is adjustable so that the air release
valve closes at a desired pump discharge flow rate depending on the
pumping system in which it is used. That is to say, individual
systems produce different liquid flow rates through the venting
valves when the system pump is primed. The valve is adjusted to
close when this "primed" flow rate occurs.
The new venting valve is constructed and arranged so that once the
pump is primed and operating the valve is maintained closed
notwithstanding variations in pump operation pressures or flow
rates which may occur during normal operation of a pumping system
over a period of time. The new valve thus insures against any
tendency for the valving member to "hunt," i.e. periodically move
between positions, or otherwise fail to close completely due to
such pressure or flow variations.
In a preferred construction, a flow responsive actuator is
associated with the valving member to assure that the valving
member is maintained in its closed position when the pump is primed
during the pumping cycle. The actuator comprises a solenoid coil
which has an armature in force transmitting relationship with the
valving member. The energization circuit for the solenoid coil
includes a control switch which completes the circuit when the pump
is primed. In one preferred system, a check valve is located
downstream from the pump and the air venting valve. The check valve
opens in response to pump discharge pressure when the pump is
primed. When the pump is at its condition point the check valve is
fully opened. The control switch is actuated to its closed position
by movement of the check valve toward the open position and when
the check valve closes the control switch is opened to interrupt
the solenoid energizing circuit.
One preferred control switch includes an operating arm actuated by
a movable part of the check valve. The operating arm is resiliently
deflectable and is situated so that the control switch closes
before the pump discharge pressure and flow conditions reach the
condition point levels. The operating arm deflects after the switch
is initially closed so that the switch is maintained closed as the
discharge pressure and flow conditions proceed to the condition
point levels. Thereafter, if the pressure or flow levels should
vary somewhat from the condition point, the switch operating arm
maintains the switch contacts closed.
In another preferred construction, the switch is a mercury switch
mounted on a movable part of the check valve. As the pressure and
flow levels increase toward the condition point levels the mercury
switch is tipped and closes just prior to the check valve opening
fully. The mercury switch remains closed throughout a range of
system operating flow conditions.
Another preferred construction employs a switch formed by a
pressure actuated contact arm which engages a second movable
contact arm throughout a range of detected pump discharge
pressures. The pressure actuated arm can be driven, for example, by
a Bourdon tube gauge needle driving mechanism. The Bourdon tube
communicates with the pump discharge pipe via a suitable pressure
fitting.
A principal object of the invention is the provision of a new and
improved self-priming pumping system including a flow actuated air
release valve which is open to vent part of the system while a pump
is being primed and wherein the air release valve is closed in
response to liquid flowing through it at a predetermined rate and
is maintained closed after the pump is primed by a flow condition
responsive actuator.
Other objects, features and advantages of the invention will be
apparent from the following detailed description made with
reference to the accompanying drawings which form part of the
specification.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic illustration of a pumping system embodying an
air release valve forming part of the invention;
FIG. 2 is a cross sectional view of the air release valve embodied
in the system illustrated in FIG. 1 having portions shown in
elevation and on a scale larger than the scale of FIG. 1;
FIG. 3 is a cross-sectional view taken on the line 3--3 of FIG.
2;
FIG. 4 is a cross-sectional, fragmentary view of a modified air
release valve including check valve structure;
FIG. 5 is a cross-sectional view taken on the line 5--5 of FIG.
4;
FIG. 6 is a cross-sectional view of a portion of the valve of FIG.
4;
FIG. 7 is a view similar to FIG. 4 illustrating another modified
air release valve construction including check valve structure;
FIG. 8 is a view taken on the line 8--8 of FIG. 7;
FIG. 9 is an elevational view with portions broken away of still
another modified valve construction;
FIG. 10 is a view taken on the line 10--10 of FIG. 9;
FIG. 11 is a view of a portion of still another modified valve
constructed according to the invention;
FIG. 12 is an elevational view of still another modified valve
constructed according to the invention;
FIG. 13 is a schematic view of another modified system employing a
supplemental actuator for a flow actuated air release valve;
FIG. 14 shows a modification of part of the system of FIG. 13;
and,
FIG. 15 shows another modification of part of the system of FIG.
13.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to the drawings, and to FIG. 1 in particular, there
is shown a conventional centrifugal self-priming pump 10 which
includes a casing having a rear wall 11, a front wall 12, and a
partition wall 13. The walls of the casing cooperate to define a
suction chamber 14 and a discharge chamber 15. An impeller 16 is
disposed within the pump casing and is supported on a shaft 17
which extends rearwardly through the rear casing wall 11 and is
connected to a suitable motor 18.
An inlet pipe fitting 25 is connected to the front wall 12 of the
casing and opens into the suction chamber 14 through a hole in the
front wall which is equipped with a suction check valve 26. An
outlet pipe fitting 27 also is connected to the casing and opens
into discharge chamber 15.
The pump 10 is illustrated as being embodied in a so-called force
main system in which a static condition of liquid is maintained at
all times in the discharge line of the pump. The system includes an
inlet pipe 35 which is connected to the inlet fitting 25 and
extends down into a suitable reservoir or tank 36 containing the
liquid to be pumped. A discharge pipe 37 is connected to the
discharge fitting 27 and extends upwardly from the pump 10. This
discharge line 37 is equipped with a check valve 38 downstream from
the pump 10 which serves to maintain a static head of liquid in the
discharge pipe above the valve 38 when the pump 10 is not operating
at rated capacity and head.
When the pump 10 has been fully primed and is operating in its
pumping cycle at rated capacity and head, a column of liquid is
maintained in the suction inlet pipe 35 and a vacuum exists in the
suction chamber 14 above the level of liquid therein. The impeller
16 operates to pump the liquid from the suction chamber 14 into the
discharge chamber 15 and out of the pump 10 through the discharge
line 37 and then through the check valve 38.
During the priming cycle of the pump 10, which will occur upon
initial operation of the pump and when, for some reason, the
suction head is lost between pumping cycles, air or gas will be
contained in the inlet pipe 35 and in the chamber 14 of the pump.
When the pump 10 is ready for priming, a quantity of liquid is
contained in the suction and discharge chambers somewhat as
indicated in FIG. 1. The pump motor 18 is energized to start
rotation of the impeller 16 to move a quantity of the liquid and
air from the suction chamber 14 into the discharge chamber 15, thus
creating a partial vacuum on the suction side of the pump.
Atmospheric pressure exerted on the liquid to be pumped forces the
liquid up the inlet pipe 35 to a height depending upon the volume
of liquid pumped out of the suction chamber and the internal
dimension of the pipe 35. In some applications, the liquid may rise
four to five feet up the pipe 35 each time the liquid is pumped out
of the suction chamber. Continued actuation of the impeller 16
continues to move quantities of liquid and air from the suction
chamber into the discharge chamber, thus causing the height of the
liquid in the pipe 35 to progressively increase. The priming cycle
is completed when a vacuum has been established in the suction
chamber 14 and the pump is operating at its rated capacity and
head.
It will be apparent from the foregoing description that it is
necessary to vent the air or gas which is pumped by the impeller 16
into the discharge chamber during the priming cycle so that the
pressure in the discharge chamber remains relatively low. Such air
or gas cannot be forced through the main discharge line 37 past the
valve 38 because of the relatively larger static pressure of the
liquid which is maintained in the discharge line downstream from
the valve. In order to vent the air or gas which is evacuated from
the suction inlet pipe 35 and the chamber 14 during the priming
cycle, the invention provides a new air release valve assembly 45
which is connected to the discharge pipe 37 between the discharge
side of the pump 10 and the valve 38. As generally explained above,
the new air release valve 45 is open during the priming cycle to
vent the air or gas evacuated from the suction inlet line and
automatically closes at the end of the priming cycle to prevent the
venting of liquid through the valve 45 during the pumping
cycle.
Referring now to FIGS. 2 and 3, the new air release valve assembly
45 is shown to comprise a valve body housing 46 including a
cup-like base member 47 and a cover 48 removably attached to the
base member. The base member 47 carries studs 49 which are threaded
into the rim 50 of the base member at spaced locations around its
circumference and which project upwardly through openings in the
cover 48 near its periphery. Wing nuts 51 or the like are threaded
on the upper ends of the studs 49 to hold the cover 48 in place.
The wing nuts 51 permit the cover 48 to be quickly removed from the
base member 47 so that the valve housing 46 can be easily cleaned
whenever necessary. A suitable O-ring seal 52 is provided between
the cover 48 and the rim 50 of the base member 47 to prevent
leakage of fluid between these parts.
The interior of the housing 46 formed by the members 47, 48 defines
a generally cylindrical vortex chamber 54. At least one inlet port
55 is formed through the side wall or rim 50 of the base member 47
to direct fluid tangentially into the vortex chamber 54. As is most
clearly shown in FIG. 3, the inlet port 55 is formed through an
external corner structure 56 which is part of the base member side
wall.
An inlet line 57 is connected to the discharge line 37 and
communicates with the inlet port 55. In the preferred construction
of the invention, a second tangential inlet port 60 is formed
through the corner structure 56 into communication with the vortex
chamber 54 at right angles to the inlet 55. The two ports 55 and
60, only one of which is used, permit either right or left hand
installation of the valve 45. The inlet port which is not in use,
for example, the port 60, is normally closed by a suitable threaded
plug 61 and may serve as a drain when the plug is removed. The
valve body housing 46 is also provided with an outlet port 62 which
extends axially from the vortex chamber 54 through a centrally
located, outwardly extending boss 63 of the base member 47. The
outlet port 62 may be connected to an outlet or discharge line 64
by a transparent nipple 65 which is threaded into the boss 63. As
more fully explained below, observation of liquid flow through the
transparent nipple 65 facilitates proper adjustment of the valve
45.
A valve seat ring 66 having a frusto-conical seating surface 67 is
mounted in a recess formed in the bottom of the base member 47
around the mouth of the outlet port 62. As shown, an O-ring 68 is
carried in a peripheral groove formed in the side wall of the seat
ring 66 and is disposed in sealing engagement with the side wall of
the recess in which the seat ring is mounted. In the preferred
construction of the valve 45, a resilient back-up ring 69 is
disposed between the seat ring 66 and the bottom of the recess in
which the seat ring is mounted. The back-up ring 69 permits limited
floating movement of the seat ring 66 to assure complete closing of
the outlet port 62 as described presently.
A valving member 75 is carried by the housing cover 48 for movement
axially of the housing into and away from engagement with the valve
seat ring 66 for opening and closing the outlet port 62. The
valving member 75 has a stem portion 76 and a head 77. The head 77
is formed to have a generally hemispherical or dome-like upper
portion 78 and a generally frusto-conical lower portion 79 which
converges from the upper portion 78 to the bottom of the head, as
viewed in FIG. 2. The frusto-conical portion 79 is engageable with
the seating surface 67 of the seat ring 66 to close the outlet port
62.
In the illustrated embodiment of the invention, the stem 76 of the
valving member 75 extends through a central, axially outwardly
projecting hub portion 80 of the housing cover 48. A bushing 81 is
threaded into the inner end of the hub portion 80 around the stem
76 and serves to support the valving member 75 for sliding movement
between its open and closed positions. The valving member 75 is
urged to a normally open position by a spring 82 which is connected
to the end of the stem 76 and to the end of an adjustment screw 83.
The spring 82 and the adjustment screw 83 are disposed within a
sleeve 84 which has one end threaded into the hub 80 and its
opposite end closed by a cap 85. The adjustment screw 83 extends
outwardly through a threaded opening in the cap 85, and a locknut
86 and a suitable sealing washer 87 are carried on the adjustment
screw for engagement with the outer surface of the cap 85.
The outwardly projecting end of the adjustment screw 83 is shown as
having a slot 88 suitable for receiving a screw driver of the like
whereby the adjustment screw 83 can be rotated to advance it in and
out of the sleeve 84. Selective adjustment of the screw 83 serves
to vary the tension of the spring 82, thereby changing the biasing
force urging the valve member 75 to its normally open position.
The operation of the valve 45 is dependent upon the creation of a
pressure differential across the housing with the inlet pressure
being greater than the outlet pressure. To this end, the outlet
port 62 of the housing 46 is made larger than the inlet port. In
the preferred construction of the valve, the outlet port 62 has a
diameter which is preferably 25% larger than that of the inlet
port. In order to prevent debris, such as rags and other solids,
from clogging the inlet port of the valve, it has been found
desirable to form the inlet port with a one inch diameter. Thus, in
a valve construction having a one inch inlet port, the outlet port
should preferably be one and one quarter inches in diameter.
When fluid is introduced into the valve 45 through one of the inlet
ports 55 or 60, a vortex flow is created within the chamber 54 so
that the fluid swirls inwardly of the housing across the inner
surface of the cover 48. This vortex flow of fluid is such that the
pressure at the upper hemispherical portion of the valve head 77 is
greater than the pressure on the frusto-conical lower portion 79.
As the flow rate of liquid into the chamber 54 increases, the
pressure differential across the head 77 also increases to
gradually pull the valving member 75 into engagement with the seat
ring 66 against the biasing force of the spring 82 thereby closing
the outlet port 62. By adjusting the tension of the spring 82, the
valving member 75 can be made to close upon any desired condition
of liquid flow through the housing 46.
The operation of the valve 45 in the illustrated pumping system
will be largely apparent from the foregoing description. Assuming
that the pump 10 is unprimed, the valve 45 will remain in its
normally open position when the pump motor is turned on to initiate
the priming cycle described above so that the air and fluid
evacuated from the pump suction lines and discharged from the
pumping chamber 15 can flow through the open valve 45 and the
connected outlet line 64. As the flow of liquid through the valve
45 increases during the priming cycle, the valving member 75 will
be pulled toward the seat ring 66 against the biasing force of the
spring 82. When the priming cycle has been completed and the pump
10 is operating at rated capacity and head, the liquid flowing
through the valve will pull the valving member 75 to its fully
closed position, thereby preventing any further discharge of liquid
through the valve during the pumping cycle. When the pump motor is
shut off at the end of the pumping cycle the valve 45 will
automatically open, but will close immediately when the pump is
restarted if the pump suction has not bee lost. If for some reason
the pump suction is lost before restarting the pump, the valve will
remain open to allow the pump to recycle and will close when full
prime has again been attained.
An important feature of the invention resides in the construction
which permits the valve 45 to be adjusted to operate at the
condition point of any pumping system, which condition point varies
from system to system depending upon such factors as the pressure
drop in the pipes or lines, the output capacity of the system, etc.
The spring-loaded valving member 75 may be adjusted to close at the
condition point of the system in which it is installed by loosening
the locknut 86 and turning the adjustment screw 83. Inward
adjustment of the screw 83 decreases the tension of the spring 82
so that the valving member 75 can close quickly under conditions of
low head. Outward adjustment of the screw 83 increases the spring
tension and the closing time of the valving member, as is required
under conditions of the high head.
The spring loaded valving member 75 is preferably adjusted after
the pump has been operated to complete its first priming cycle.
Such adjustment is facilitated by the transparent nipple 65
connected to the outlet of the valve 45. The priming cycle is
completed when full liquid flow is observed through the nipple, and
at that time the tension of the spring 82 is properly adjusted so
that the valving member closes and remains closed during the
pumping cycle. When adjusted, the valve 45 will operate
automatically during subsequent cycles of the pump and no further
attention is required.
Reference is now made to FIGS. 4-12 which illustrate different
check valve arrangements which may be associated with the air
release valve 45 for the purpose of preventing a reverse flow of
air through the valve 45 into the pumping chamber 15 when the pump
is not in operation. As previously described, the valve 45 opens
automatically at the conclusion of each pumping cycle. Any reverse
flow of air through the valve when the pump has been stopped could
result in a loss of pump suction if the suction valve 26 is not
completely closed. The check valve arrangements of FIGS. 4-12
insure against loss of pump suction by blocking reverse flow of air
through the valve 45 when it is open.
Referring particularly to FIGS. 4-6 there is shown a check valve
construction 115 which is disposed in the vortex chamber of the
pump 45 and adapted to block the inlet port 55 when the pressure in
the vortex chamber 54 approaches the pressure in the inlet line 57.
The check valve assembly 115 includes a rectangular pad-like check
valve member 116 of resilient rubber-like material which extends
across ports 55, 60 so that, when the check valve member 116 is in
the position illustrated in FIG. 4, air flow from the vortex
chamber through the inlet 57 is prevented. The check valve member
116 is urged to its closed position by a spring construction
including spring strips 120, 121 which are formed of suitable
corrosion resistant material, such as stainless steel, and
connected to the member 116 by rivets 122. The check valve member
116 and the spring strips 120, 121 are supported in the chamber 54
by a pintle 125, the ends of which are received in cylindrical
cavities 126, 127 formed in the cover and base of the valve 45
respectively. The spring strip 121 is bent to define a loop 130
medially of its ends through which the pintle 125 extends.
FIG. 6 illustrates the check valve construction 115 in a relaxed
condition. It is apparent that when the check valve construction is
mounted in the chamber the spring strips 120, 121 are deflected
from their relaxed conditions and urge the check valve member 116
firmly against the side wall of the chamber. Accordingly the check
member prevents flow from the vortex chamber through the inlet line
57 when the fluid pressure force in the vortex chamber and the
force of the springs 120, 121 are greater than the pressure force
exerted on the valve member by the fluid pressure in the inlet port
55.
The check valve construction 115 permits tangential flows of gas
and the liquid into the vortex chamber 54 regardless of whether the
flow is introduced through the inlet port 55 or the inlet port 60.
When flow is directed into the chamber 54 through the inlet port
55, the end 131 of the check valve member 116 is deflected toward
the center of the chamber. The opposite end 132 of the check valve
member is maintained in the closed position. If the flow is
directed into the chamber through the inlet port 60 the end 132 is
deflected into the vortex chamber 54 while the end 131 remains
stationary.
FIGS. 7 and 8 illustrate a modified check valve assembly 135
disposed in the vortex chamber 54. The check valve assembly 135
includes a flapper-like valve member 136 in the form of a
rectangular strip of rubber-like material positioned across the
inlet ports 55, 60 and supported in position by a clamp 137. The
clamp 137 is connected to the side wall of the vortex chamber by
screws 142 extending into tapped holes 145a in the side wall which
cause the clamp to tightly grip the valve member 136.
The inherent resilience of the valve member 136 normally maintains
it closed across the inlet ports 55, 60 (see FIG. 7). The end 143
of the valve member is deflected into the vortex chamber 54 only in
response to fluid flow into the chamber through the inlet port
55.
In applications in which fluid is introduced through the port 60
the check valve assembly 135 is turned end for end in the chamber
and the screws 142 are threaded into holes 145b so that fluid flow
from the inlet port 60 is directed tangentially into the vortex
chamber past the free end of the valve member.
FIGS. 9 and 10 illustrate a gas venting assembly valve 45 utilizing
a "duck bill" type check valve 150 for preventing reverse air flow
through the valve 45. The check valve 150 is formed of a
rubber-like material and includes a pair of lips 151, 152 and an
integral annular flange 153. The check valve 150 is held in
position by engagement of the flange 153 below the seat ring 66 so
that the lips 151, 152 can close the outlet port 62. The flow of
liquid through the valve 45 forces the lips 151, 152 apart
permitting relatively unimpeded flow of the fluid to the discharge
pipe 64. When the pressure in the discharge pipe is equal to or
greater than the pressure in the chamber, the lips 151, 152 move
together to close the outlet port 62 and prevent air flow from the
pipe 64 into the chamber 54.
FIG. 11 illustrates a modified check valve 150' which is
substantially the same as the check valve 150 FIGS. 9 and 10 except
that four lips 160-163 are provided. The modified valve 150' is
disposed in the air release valve 45 in the same manner as the
valve 150, and, since it operates substantially in the same manner
as the check valve 150, further description is believed
unnecessary.
FIG. 12 illustrates a further modified air release valve 45
including swing-type check valves 170, 171 in the inlet and outlet
lines 57, 64 respectively. Each valve assembly includes a housing
173 which supports a swing-type valve member 174 rotatable about a
hinged support 175 in the housing. The valve member 174 moves about
a pivot axis 176 to permit flow from the pipe 57 through the valve
45 to the outlet pipe 64. The valve member closes to prevent flow
in the opposite direction and in the illustrated construction is
moved to the closed position by gravity. Although two check valves
170 are illustrated in FIG. 12, in practice, only one of these
check valves is necessary to prevent the reverse flow of air
through the valve 45.
A modified force main pumping system 200 is illustrated in FIG. 13.
The system 200 comprises a pump 202, a pump inlet pipe 204 and a
pump discharge pipe 206. The pump 202 draws liquid upwardly through
the inlet pipe 204 and forces the liquid through the discharge pipe
206 via a discharge check valve 208. An air release valve assembly
210 communicates with the discharge pipe 206 between the check
valve 208 and the pump 202. When the pump is being primed and the
check valve 208 is closed, air or other gas in the pump is vented
to atmosphere. This enables the pump to be primed. When the pump is
primed and operating, the air release valve 210 closes so that
pumped liquid from the discharge pipe cannot vent from the system.
The pump 202 may be of any suitable or conventional construction
and can be the same as the pump 10 described above in reference to
FIGS. 1-12.
The check valve 208 functions the same as the check valve 38
referred to in connection with FIG. 1. That is, when the pump is
not operating, the check valve 208 is closed to maintain a head of
liquid in the discharge pipe above the check valve. The valve 208
remains closed during priming of the pump to allow the pump to vent
air through the air release valve. When the pump is primed and
operating the discharge pressure opens the check valve 208 and
liquid is pumped through the discharge pipe.
The check valve 208 comprises a tubular valve housing 212 integral
with the pump discharge pipe and a movable valve member 214 which
is disposed in the valve housing 212 for movement between a closed
position, illustrated in FIG. 13, and an open position in which
pumped liquid passes upwardly through the valve housing and the
discharge pipe 206. The valve member 214 is fixed on a pivot shaft
216 which is journalled in the valve housing 212.
The valve member 214 is biased to its closed position. The pivot
shaft 216 carries a lever arm 218 which is connected to the shaft
on the exterior of the valve housing. The lever arm 218 is
connected to a return spring 220 which is preferably a helical
tension spring having its opposite end anchored to the housing 212.
The spring 220 maintains the lever arm and valve plate member 214
in the positions corresponding to the closed position of the
valve.
The air release valve unit 210 is connected between the pump and
the check valve 208 for venting the discharge pipe when the pump is
priming. The valve unit 210 comprises a cylindrical valve housing
222 which defines a cylindrical vortex chamber 224. An inlet pipe
226 extends between the pump discharge pipe 206 and the housing
222. The inlet pipe opens tangentially into the cylindrical
chamber. An outlet pipe 228 extends the the housing 222 along the
axis of the cylindrical chamber so that the liquid flowing through
the chamber forms a vortex having its center located over an output
port 230 in the lower wall of the chamber along the axis of the
housing. The housing 222 and associated parts thus far described
are shown schematically and may be the same as is described in
reference to FIGS. 1-13.
Flow through the chamber 224 is controlled by a flow actuated valve
member 232 movably disposed in the housing 222. The valve member
232 includes a head portion 234 disposed in the vortex chamber and
a cylindrical valve stem 236 which projects through an opening 238
in the upper wall of the housing. A seal 240 surrounds the valve
stem 236 and prevents the escape of liquid from the chamber between
the valve body and the housing 222. The valve member 232 moves in
the housing so that the head 234 blocks the outlet port 230 and
terminates flow through the chamber. The valve member 232 is biased
towards its open position by a spring 242. The biasing spring 242
is preferably a helical compression spring which surrounds the
valve stem and is compressed between a boss area 244 surrounding
the opening 238 and an annular collar 246 which is carried on the
valve stem. The collar 246 is movable along the valve stem by a
suitable screw thread adjusting arrangement which is not
illustrated in detail. The general operation of the air venting
valve unit 210 as thus far described is the same as has been
described in reference to FIGS. 1-12.
The modified system 200 differs in that operation of the air
release valve unit is augmented by a flow condition responsive
actuator 250 which applies a positive valve actuating force to the
valve member 232 in response to predetermined flow conditions of
the liquid in the pump discharge pipe. As is illustrated in FIG.
13, the actuator 250 includes a solenoid coil assembly 252 which is
connected across a suitable electrical power supply (not shown) by
conductors 256, 258 in series with a control switch 260. An
armature 261 of the solenoid assembly is connected to the valve
stem 236 so that when the solenoid coil 252 is energized the
armature 261 is "pulled in" and forces the valve stem to a position
in which the head 234 covers the outlet port 230.
In the illustrated embodiment, the control switch 260 is preferably
a normally open switch of the micro switch type which is mounted
adjacent the lever arm 218. The contacts of the switch 260 are
actuated to the closed position by a cat-whisker spring lever 262
which is positioned for engagement by the lever arm 218 whenever
the check valve 208 has moved from the closed position toward a
predetermined at least partly open position.
As noted above, the valve 208 does not open at all until the pump
discharge liquid pressure is greater than the head pressure of the
liquid standing over the check valve 208. When this occurs the pump
is primed and flow through the valve housing 212 opens the valve
208. When the valve member 214 has moved a predetermined amount
from the closed position the cat-whisker spring lever 262 is
engaged by the lever arm 218 and the switch 260 closes. This
energizes the solenoid 252 to force the valve member 232 to its
closed position, if it is not already closed. The actuator 250
thereafter prevents the valve member from moving from its closed
position.
The lever arm 218 maintains engagement with the spring lever 262 so
that the solenoid remains energized so long as the pump is primed
and is pumping at about its operating condition to force liquid
upwardly through the discharge pipe. In the event the pump
discharge pressure is momentarily reduced for any reason, the check
valve 208 will move toward its closed position. So long as the
discharge pressure does not drop below a predetermined level, the
lever arm 218 maintains contact with the spring lever 262 so that
the solenoid assembly 252 is maintained energized through the range
of pump discharge pressures.
An alternate switch 270 is illustrated in FIG. 14 for controlling
the solenoid assembly 252. The switch 270 is a pressure responsive
switch having rotatable contact arms 272, 274. The contact arms
272, 274 are connected in an energizing circuit for the solenoid
252 so that when the arms are engaged the solenoid is energized and
when the arms are disengaged the solenoid is deenergized. The
contact arm 272 is mounted on a rock shaft 276 which is in turn
connected to a Bourdon tube gauge needle actuator 278 which is
shown schematically. The actuator 278 may be of any suitable
well-known construction and is therefore not described in detail.
The Bourdon tube of the actuator 278 communicates with the pump
discharge pipe through a pressure fitting 280. When the pump
discharge pressure increases, the contact arm 272 is rotated
clockwise as seen in FIG. 14 with the amount of rotation of the arm
being proportional to the pressure level.
When the pump is primed, the liquid pressure in the discharge pipe
increases toward the condition point pressure level causing the
contact arm 272 to rotate clockwise as shown in FIG. 14. The
contact arm 274 has a rest position, shown in FIG. 14, at which the
arm 274 remains during the priming cycle. When the pump is primed
and the discharge pressure increases toward the condition point
level the arm 272 engages the arm 274 at its rest position
whereupon the solenoid 252 is energized. As the discharge pressure
continues to increase, the arm 272 moves the contact arm 274
clockwise from its rest position maintaining the solenoid 252
energized. The contact arm 272 has a finger 281 which extends into
the plane of the contact arm 274 to assure engagement between the
contact arms. The switch contact arm 274 is connected to a shaft
282 which is rotatably supported adjacent the shaft 276. The shaft
282 and the arm 274 are biased toward the rest position of the arm
so that when the discharge pressure is reduced, the arm 274 and the
shaft 282 move counterclockwise toward the rest position. The arm
274 can be adjusted circumferentially on the shaft 282 so that the
rest position assumed by the contact arm 274 is adjustable. As is
shown in FIG. 14, the arm 274 is set to be engaged by the arm 272
when the pump discharge pressure moves the arm 272 to extend along
the line 286. As the pressure continues to increase, the arms 272,
274 are maintained in engagement so that the solenoid 252 is
maintained energized to positively close the air release valve. The
pump reaches its operating point when the arm 272 extends along the
line 288.
Since the switch arm 274 is biased toward its position illustrated
in FIG. 14, any momentary reductions in the pump discharge pressure
from the condition point level do not open the switch so long as
the discharge pressure remains in the range between the lines 286,
288 indicated by the arrow 289.
FIG. 15 illustrates another alternate switching arrangement
employing a mercury switch assembly 290 for controlling the
solenoid assembly 252. The switch assembly 290 comprises a housing
292 which is connected to the lever arm 218 by a bracket 294. The
housing 292 defines a chamber 296 in which contacts 298, 300 are
positioned at one end. A mass of mercury 302 is disposed in the
chamber 296 and is free to move back and forth in the chamber as
the chamber is tilted relative to horizontal. The bracket 294 is
adjustable to enable the orientation of the housing 292 to be
adjusted as desired relative to horizontal. When the check valve
member has opened a predetermined amount, the mercury mass 302
moves under influence of gravity to engage the contacts 298, 300
and thereby complete an electrical energizing circuit for the
solenoid coil assembly 252 resulting in the valve member being
urged into closed position by the armature 261.
It can now be seen that the objects heretofore enumerated and
others have been accomplished and that a new air release valve
combined with a pump has been provided which vents gas from the
pump discharge during priming and automatically closes to prevent
pumped liquid from venting when the pump operates at rated head and
capacity. While a number of different embodiments of the invention
have been illustrated and described, the invention is not to be
considered limited to the precise constructions disclosed. It is
intended that all adaptations, modifications and uses of the
invention falling within the scope of the appended claims be
covered.
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