US3582227A

US3582227A - Liquid supply pump

Info

Publication number: US3582227A
Application number: US888245A
Authority: US
Inventors: Wallace W Velie; Kimble F Tesh
Original assignee: North American Rockwell Corp
Current assignee: Boeing North American Inc
Priority date: 1969-12-29
Filing date: 1969-12-29
Publication date: 1971-06-01
Anticipated expiration: 1988-06-01
Also published as: DE2052518A1; GB1273894A; ES385056A1; SE361192B

Abstract

A pump assembly to supply liquid at a low pressure to an apparatus consists of a vacuum activated fuel lift device wherein fuel from a submerged or raised fuel supply tank is caused to flow by ambient pressure into a chamber. As a centrifugal pump empties the chamber it creates a partial vacuum within the chamber which acts on a diaphragm device subsequently opening a valve which causes liquid stored at ambient pressure to enter the partially evacuated chamber. Means are provided to open the chamber to atmosphere when the pump reservoir is filled to capacity.

Description

Umted States Patent w13,5s2,227

[72] inventors Wallace W. Velie 2,786,420 3/1957 Kenney 415/26 Woodland Hills; 2,945,446 7/1960 Mason et al. 4l5/24X Kimble F. Tesh, Sepulveda, both of, Calif. Primary Examiner camon R. Croyle {g 323 3 I 969 Assistant ExaminerRichard E. Gluck [45 Pawmcd June I 1971 Anorneys--L. Lee Humphnes and Thomas S. MacDonald {73] Assignee North American Rockwell Corporation [54] LIQUID SUPPLY PUMP 7 Claims, 5 Drawing Figs.

[52] US. Cl 415/24, ABSTRACT; A pump assembly to supply liquid at a low pres- 415/26 sure to an apparatus consists of a vacuum activated fuel lift [51] lnt.Cl ..F0lb 25/00, d i wherein f l f a submerged or raised f l Supply Fold F03d tank is caused to flow by ambient pressure into a chamber. As [50] Fleld of Search 417/205, 3 cemrifugal pump empties the chamber it creates a partial 200, 40, 249, 253, 2! L5; 415/24, 1 2 vacuum within the chamber which' acts on a diaphragm device subsequently opening a valve which causes liquid stored at [56] References cued ambient pressure to enter the partially evacuated chamber. UNITED STATES PATENTS Means are provided to open the chamber to atmosphere when 2,322,910 6/ l 943 Adney et al 4l5/24X the pump reservoir is filled to capacity.

uoum SUPPLY PUMP BACKGROUND OF THE INVENTION There are many types of vacuum operated pumps on the market, particularly in the automotive field. These pumps invariably derive their vacuum source from the intake manifolds of an internal combustion engine. A typical vacuum pumpjust described is the subject of U.S. Pat. No. l,62l,8l7. This patent uses a float assembly that actuates three different shutoff valves. A pendulum action controls two valves on one arm of the float assembly extending from a pivot and one valve on the opposite arm so that when the float chamber is depleted the float position is towards the bottom of the float chamber thereby allowing liquid from a remote tank to enter the chamber. The force causing the liquid to flow into the float chamber is a vacuum created by the engine manifold which is controlled by a-valve on one side of the fulcrum action of the float. As the float'comes up in the chamber the vacuum source is shut down and the liquid source is shut off. At the same time the valve isolating the chamber from the atmosphere is open, allowing atmospheric pressure to enter the chamber which causes the liquid to move to a second chamber for admittance to the intake manifold of the engine.

The foregoing prior art pump as well as similar types of pump devices use mechanically actuated shutoff valves as part of the pump which are operable by levers cantilevered off a float valve which is swivelly hinged to the body of the chamber. If the mechanically actuated valve should not completely shut off the vacuum line from the engine, then the float chamber is in danger of over filling, i.e., dumping liquid overboard through the valve vents. The pumps additionally are hindered by wear which multiples with each additional mechanically actuated valve.

Other known vacuum pumps in the prior art disclose minor variations of the above described patent. These devices all require a separate vacuum pumping source and all of them use mechanically actuatable shutoff valves that are controlled by a float suspended in liquid.

A disadvantage in conventional vacuum pumps is the sensitivity of the shutoff valve between the liquid supply source and the pump. The valve is subject to malfunction due either to wear or toforeign objects being trapped between the seat of the valve and the valve body. Obviously, if the mechanically actuated shutoff valves should encounter a problem, the sensitive balance of liquid within the chamber is upset.

Another disadvantage would be the danger of overflow through the vents due to float assemblymalfunctions causing a potential fire hazard, etc.

Still another disadvantage in the prior art is encountered when a vacuum pumping apparatus is employed wherein liquid is prevented from entering the float chamber from a supply source by blockage of the line to the external vacuum source and venting the float chamber to atmosphere. A positive head fuel supply cannot be used since there is nothing to stop flow through the apparatus and out through the vents open to the atmosphere. The fuel supply source must be physically located below the carburetor.

A further disadvantage exists in a pumping apparatus which directly blocks the line from the fuel supply source to the pump. Operation is possible with a positive head, however any leak or siphoning action within the float chamber will empty the chamber.

Accordingly, it is an object of this invention to provide a vacuum liquid supply pump with a positive shutoff capability.

More particularly, it is an object of this invention to provide a vacuum liquid supply pump having a positive shutoff capability which does not require a separate vacuum supply and which includes a pneumatically operated valve actuation device whichis not dependent upon positive mechanical float linkages to operate.

SUMMARY OF THE INVENTION The liquid supply pump basically is a vacuum fuel lift device having a low head liquid supply and a positive liquid shutoff capability. The device has utility in, for example, fuel burners which will operate with the fuel supply tank either physically located above or below the burner level. A particle vacuum is created when a centrifugal pump ejects liquid from a sealed chamber causing flow from an elevated or submerged storage tank into the chamber by atmospheric pressure. A float valve in an adjacent chamber will periodically vent the pump assembly to ambient pressure when fuel level becomes sufficient within the second chamber. Ambient pressure will close a common vacuum operated fuel shutoff valve shutting off the supply from the remote tank. .When the fuel in the float chamber becomes sufficiently low, the float valve will close permitting evacuation of the sealed chamber and subsequent refilling from the fuel supply tank. The refilling process is continuously repeatable during pump operation. The liquid supply system disclosed is especially suited, for example, in an oil burner requiring a low pressure fuel supply system which is also capable of lifting fuel from a remotely located tank and providing a positive fuel shutoff to avoid fuel flooding or overflow. The pump is most suitable for use with, for example, oil burners having a pneumatic fuel atomizer system which atomizes liquid for proper combustion.

When operating, one side of a positive shutoff valve actuator opposite a shutoff valve is evacuated. The differential pressure across the pneumatic piston causes it to move against a spring and to open the valve communicating with a remotely located liquid supply tank. Ambient pressure in the supply tank causes the fuel to flow into the partially evacuated chamber. The liquid is subsequently pumped into an adjacent chamber containing a liquid level float and associated valve. The fuel is pumped into the chamber containing the float until the level reaches a point at which the float lifts a valve located in a barrier wall between the two chambers subjecting the sealed chamber being fed by the remotely located tank to ambient pressure, thereby causing the pneumatic piston to move back to its normal position causing the valve communicating with the remotely located supply tank to be closed, thus, shutting off the supply from the tank to the sealed chamber. When the chamber containing the float is depleted due to action of a second pump which pumps the liquid out of the float containing chamber, the valve attached to the float again closes, sealing the lower chamber thereby causing the pneumatic piston again to be affected by a lessening in pressure in the bottom chamber, thereby reopening the main supply valve starting the cycle over again. A,

The vacuum lift pump continues to operate in a cycli fashion as hereinbefore described. When both chambers are full, the valve controlled by the float remains open, therefore the liquid merely flows from the lower chamber to the upper chamber and back down to the lower chamber until such a time as the upper chamber becomes depleted causing the float to drop and the valve to be shut off, thereby triggering the refilling cycle.

An advantage over the prior art is the absence of mechanical linkages controlling the valve which causes the liquid to flow into one of two chambers.

Another advantage over the prior art is the absence of an external vacuum source.

Still another advantage is the ability to locate the liquid supply tank either above or below the pumping apparatus.

Yet another advantage is the fail-safe feature wherein any leakage within the vacuum pump automatically shuts off the supply from the liquid supply source to the pump thereby obviating any possibility of a leak.

Still another advantage is the capability to lift liquid under ambient pressure from a remote liquid supply source without resorting to close tolerance gear pumps and the like.

DESCRIPTION OF THE DRAWINGS The above-noted objects and further advantages of the present invention will be more fully understood upon the study of the following detailed description in conjunction with the detailed drawings in which:

FIG. I is a partially cutaway plan view of the preferred embodiment of the invention;

FIG. 2 is a cutaway section taken along lines 2-2 of FIG. 1 showing the upper and lower chambers and their interrelationships;

FIG. 3 is a section taken along lines 3-3 of FIG. I showing the details of the float and valve combination;

FIG. 4 is an enlarged view of the pneumatic valve assembly which communicates with and controls the flow of fluid from a remotely located tank to one of the supply chambers;

FIG. 5 is a view taken along lines 5-5 of FIG. 2 which shows the details of the pump which supplies an apparatus to be fed by the pump.

Referring now to FIGS. I and 2, the fluid supply pump generally designated as consists of housing 12 which basically encloses a lower chamber 14 (FIG. 2) and an upper chamber 16. The cutaway section shown in FIG. 2 reveals the basic components including a fuel supply inlet 18 which communicates with a remotely located liquid supply tank (not shown), a valve 20, and a pressure sensitive diaphragm 32. A pair of commonly driven axially aligned

centrifugal pumps

40 and 50 are connected to a common drive shaft 52. The shaft 52 is connected directly to the radially extending impeller blades 53 of centrifugal pump 50 which extend into an annulus 57. The drive shaft 52 extends below pump 50 and is splined onto a shaft 56 at union 54. A pin 55 transmits the rotary driving force to pump 40 which has impeller blades 42 extending into the cavity or annulus 44. A passageway 46 communicates at one end with annulus 44 and empties into the upper chamber 16 at the other end exiting at port 48. The upper chamber 16 essentially houses the float assembly 60 (FIG. 1) as well as the primary centrifugal pump assembly 50. Float assembly 60 is comprised of a pair of

arms

62 and 64 which are pivotably anchored to floor 13 by

pivots

63 and 65. Integral with pivot arm 62 is a valve assembly 70 (FIG. 3) which is operably by float assembly 60. The shutoff valve is adjustable by positioning a nut 74 which is in threadable engagement with .a shaft 72.

Referring now to FIG. 4, the valve assembly 20 which communicates at inlet 18 directly with a liquid supply source (not shown) comprises a ball valve 22, a spring 24 housed within a valve body 26 which slides within cylinder 27. The cylinder 27 has, at its free end, an inwardly extending lip 28 which prevents the center body 26 from extending through the body 27. The top of center body 26 contains a pair of axially extending

conduits

21 and 23.

The controlling apparatus for the valve 20 is in the diaphragm assembly 30 which is attached to the intermediate wall 13 and consists of an upper plate 31, a flexible diaphragm 32 and a lower support plate 33. A central shaft 34 connects together plate 31, diaphragm 32, and lower plate 33, as well as providing for an interconnecting pad 35 which is aligned with the valve body 26 by pin 36. A rubberlike washer 37 acts as a cushion for pad 35 and the end of the center body 26. Washer 37 also acts as a sealing surface or seat for the valve 20 while it is in a closed position.

Ball valve 22 serves a very specialized purpose. If the remotely located liquid supply tank is physically located a relatively long distance below the pump and the impedance (resistance) of the conduit feeding inlet 18 is low, there is a possibility of a negative pressure within chamber 14 occuring when the pump is shut down caused by the liquid returning to the supply tank. If there were no check ball valve 22, the rush of liquid back to the supply tank could deflect diaphragm assembly 30 downward holding valve 20 open causing liquid to reverse itself from the normal direction of flow from chamber 16 back through port 48 into the annulus 44, finally returning to chamber 14. Since the impedance in conduit 46 is higher than the impedance in the liquid supply feed line, there is a possibility of liquid being displaced by air within chamber 14. Check valve 22 prevents or slows down the rush of liquid back to the supply tank allowing valve 20 to close thereby obviating any possibility of air entering chamber 14.

In operation, the liquid in chamber 14 is pumped by centrifugal pump 40 from chamber 14 through internal conduit 46 and out port 48 into chamber 16. Chamber 14 is always filled to capacity with liquid. As the pressure within chamber 14 diminishes, a partial vacuum occurs within the chamber due to the pumping action of pump 40. This vacuum acts on diaphragm assembly 30 which deflects the diaphragm downwardly forcing valve body 26 against spring 24 thereby uncovering ports 21 and 23'exposing them to chamber 14. The partial vacuum within the chamber acts to draw liquid under ambient pressure from the remotely located supply tank in through inlet 18, past ball valve 22 and out through

ports

21 and 23, thereby replenishing chamber 14 to capacity. As the level rises in the upper chamber 16 by the pumping action of centrifugal pump 40, the float assembly 60 rises within the chamber. As seen in FIG. 3, as the float assembly rises, the valve assembly is lifted off valve seat 76. Upper chamber 16 is exposed to atmospheric pressure through conduit or opening 17. Since valve assembly 70 is in the communication with lower chamber 14, the float assembly 60 lifts the valve off of valve seat 76 thereby exposing the lower chamber to atmospheric pressure. When this happens, the partial vacuum created in lower chamber 14 is lost, hence the diaphragm assembly returns to a normal position which recloses the spring biased valve assembly 20 thereby stopping the flow of liquid from the external liquid supply source. Air is discouraged from entering chamber 14 by the coacting mechanism within both chambers.

The upper chamber 16 is evacuated by centrifugal pump assembly 50, seen more clearly in FIG. 5. The impeller blades 53 force liquid out of annulus 57, out through conduit 58 toward exit 59. Needle valve assembly 80 meters liquid passing through conduit 58 into exit conduit 59 dependent upon the operating pressure or flow desired. The needle valve 82 is threadably engaged with housing 12 and is adjustable at port 15.

When the upper chamber 16 is evacuated by a centrifugal pump assembly 50, the level of the float assembly 60 drops thereby closing valve 70 which seals lower chamber 14 causing the diaphragm to again downwardly deflect as the lower chamber is depleted thereby starting the filling cycle over again.

When both

chamber

14 and 16 are full, the valve assembly 70 remains open and the liquid is merely circulated from the lower chamber, through the upper chamber; down again into the lower chamber via opened valve 70 until such a time as there is again a liquid demand from upper chamber 16 which recycles the pump.

It should be noted here that, if the float assembly 60 is lodged in the open position whereby valve 70 cannot close, then the lower chamber 14 is exposed to atmospheric pressure which will maintain the diaphragm assembly 30 in the normal position thereby preventing further liquid from the supply tank from entering the pump through the valve assembly 20 thereby providing a fail-safe condition. Thus, the pump assembly cannot overflow.

We claim:

1. A liquid supply pump comprising:

a housing,

a first chamber within said housing having a liquid inlet means communicating with said chamber, a second chamber within said housing in flow communication with said first chamber, said second chamber having a liquid exit means,

a first circulating pump means within said first chamber for pumping liquid from said first chamber to said second chamber,

a second pump means within said second chamber to pump liquid from said second chamber through said liquid exit means,

pressure sensitive valve means in said first chamber, said valve means being responsive to change in pressure to admit liquid through said liquid inlet means when the pressure within said first chamber is below ambient pressure, A

liquid level sensing means within said second chamber, and,

a second valve means connected to said sensing means, said valve beingin communication with said first chamber so as to expose said first chamber to ambient pressure when the liquid level within said second chamber is at a predetermined level thereby shutting off the flow through said inlet means to said first chamber.

2. The invention as set forth in claim 1 wherein said first chamber is below said second chamber, said first and second chamber being divided by a common barrier.

3. The invention as set forth in claim 2 wherein said pressure sensitive valve means in said first chamber comprises a diaphragm assembly connected to said barrier responsive to pressure within said chamber, said diaphragm being connected to a valve assembly in communication with said fluid inlet means whereby a pressure below ambient pressure causes a deflection of the diaphragm which actuates said valve to cause liquid under ambient pressure from a liquid supply source to enter said first chamber.

4. The invention as set forth in claim 3 wherein said liquid supply source is a remotely located tank, its position being either above or below said liquid supply pump without adversely affecting the operation of the pump.

5. The invention as set forth in claim 1 wherein said first and second pumps are centrifugal pumps and are attached to a common shaft extending through said first and second chamber.

6. The invention as set forth in claim I wherein said first circulating pump means creates an internal vacuum within said first chamber when said pump lowers the liquid level within said first chamber during pump actuation.

7. The invention as set forth in claim I wherein said first circulating pump means within said first chamber pumps liquid through a channel within the sidewall of said first and second chamber, said channel connected at one end to an annulus of said first pump and exiting at its other end into said second chamber.

Claims

1. A liquid supply pump comprising: a housing, a first chamber within said housing having a liquid inlet means communicating with said chamber, a second chamber within said housing in flow communication with said first chamber, said second chamber having a liquid exit means, a first circulating pump means within said first chamber for pumping liquid from said first chamber to said second chamber, a second pump means within said second chamber to pump liquid from said second chamber through said liquid exit means, pressure sensitive valve means in said first chamber, said valve means being responsive to change in pressure to admit liquid through said liquid inlet means when the pressure within said first chamber is below ambient pressure, liquid level sensing means within said second chamber, and, a second valve means connected to said sensing means, said valve being in communication with said first chamber so as to expose said first chamber to ambient pressure when the liquid level within said second chamber is at a predetermined level thereby shutting off the flow through said inlet means to said first chamber.

6. The invention as set forth in claim 1 wherein said first circulating pump means creates an internal vacuum within said first chamber when said pump lowers the liquid level within said first chamber during pump actuation.

7. The invention as set forth in claim 1 wherein said first circulating pump means within said first chamber pumps liquid through a channel within the sidewall of said first and second chamber, said channel connected at one end to an annulus of said first pump and exiting at its other end into said second chamber.