US2416590A - Vacuum relief mechanism for pumps - Google Patents

Description

Feb. 25, 1947. A. v. MUELLER ,5

I VACUUM RELIEF MECHANISM FOR PUIPS Filed Aug. 22, 1944 4 Sheets-Sheet 1 uvmvron AzExA/vom MHz/cum Arron NEYJ Feb. '25,- 1947.

A. V. MUELLER VACUUM RELIEF MECHANISM FOR PUMPS Filed Aug. 22, 1944 4Shaets-Sheet 2 Feb. 25, 1947. A. v. MUELLER, 2,416,590

VAQUUII RELIEF MECHANISM FOR PUMPS Filed Aug. 22, 1944 4 Sheets-Sheet s d v c E a A '5 62 1 4 70 v IN VEN TOR.

AFXMDfR M/Yucuep Feba 25,1947. I v v, MUELLER 2,416,590

' VACUUM RELIEF MECHANISM FOR PUMPS "4 Sheets-Sheet 4 Filed Aug, 22, 1944 mmvroa Aux/won k w m u Mm Patented Feb. 25, 1947 PATENT OFFICE 2,416,590 VACUUM RELIEF MECHANISM FOR PUMPS Alexander V. Mueller, Salem, Ohio, assignor to The Deming Company, Salem, Ohio, a corporation of Ohio Application August 22 1944, Serial No. 550,549

25 Claims.

This invention relates to a pump of the type having a, suction chamber adapted in normal operation to retain a quantity of liquid at the impeller. The primary object of the invention is to provide means to prevent the liquid in the suction pipe siphoning out the liquid in the suction chamber in case the pump loses its prime, the result being that sufilcient liquid is at all times retained in the chamber to insurere-priming of the pump.

I have found that I can accomplish the desired result of preventing the siphoning of the liquid from in the suction chamber by admitting air at the proper time and for a proper length of time to the upper portion of the chamber in case the pump loses its prime. It is an object'of the invention to provide a simple and eflicient means for automatically causing such admission of air at the proper time and insuring the automatic termination of such admission.

My invention will be more apparent from the detailed description about to follow of two embodiments thereof illustrated in the drawings.

In the drawings, Fig. l is a vertical section of a centrifugal pump having my invention, the section extending in the plane in which the axis of the impeller shaft lies; Fig. 2 is a vertical section through the suction chamber and through my controlling mechanism in off-set planes'indicated by the line 2-2 on Fig. 1; Figs. 3 and 4 30 are diagrams illustratin the operation of the control mechanism shown in Figs. 1 and 2; Fig. 5 is a vertical section in a plane similar to that of Fig. 1, showing a modified form of control mechanism; Fig. 6 is a horizontal section in a plane indicated by the line 6-6 on Fig. 5.

Referring first to Figs. 1 and 2, I0 indicates a portion of a pump frame and a casing secured thereto, formed internally with an impeller chamber 2i, shown as of volute form terminating in a, discharge portion 22; a discharge chamber 23 into which such portion discharges, and a suction chamber havin an intake portion 25, a divided downward portion 26 and a final portion 21 leading to the impeller chamber. In the upper part of the casing is a valve chamber 28 which my mechanism hereinafter described controls, this chamber communicating with the suction intake portion by a passage 29 through 50 vents the water which is receding in the suction an internal Wall at the top of the passageway.

A bonnet 30 arranged to the usual suction pipe is secured to the outer face of the casing 20 in registration with the suction passageway 25. The suction pipe is not illustrated in the drawings but generally extends from the bonnet 30 down- 2 wardly to a. well or sump from which the fluid is being withdrawn.

Within the impeller chamber 2| is a suitable I impeller mounted on the end of a shaft 4|.

10 rotated by external mechanism not shown, the

rotation of the impeller establishes suction in the passageway 21, 2B, 25, draws liquid up the suction pipe, discharges it through the impeller casing into the discharge chamber 23, whence it 15 passes up the discharge pipe secured to the top of casing 20.

In normal operation, the entire suction chamber from the suction pipe inwardly and thence downwardly and forwardly to the eye of the im- 20 peller is filled with liquid, and the rotating impeller discharges such liquid upwardly through its casing into the discharge chamber and thence out through the discharge pipe, and the mechanism of this invention is idle. It is when the impeller for some reason loses its prime that my invention comes into play. This may happen for instance, when a quantity of air is drawn into the suction chamber (as when the level of the liquid being pumped falls below the entrance to -,the suction pipe) and this air reaching the eye of the impeller prevents its effective action. Under such circumstances there is a tendency of the liquid in the suction pipe to drop and, unless a check valve seats tightly, the liquid will be siphoned from the suction chamber and it will be necessary to re-prime the pump and re-establish the suction to resume operation.

The usual means employed to prevent siphon- 40 ing is a check valve atthe entrance of .the suction 45 about to be explained, prevents the siphoning independently of the check valve by admitting air for a short time through the check valve chamber 28 and the opening 29 into the upper portion 25 of the suction chamber and this prepipe from siphoning the water out of the suction chamber, particularly out of the portions 26 and 21 thereof. I thus retain an adequate supply of water in the suction chamber to re-prime the pump, insuring continuous operation. This aaiaoeo 3 will be clear from the following description of the mechanism shown.

P In Figs. 1 and 2, BB designates a horizontal plate-like frame tightly mounted on top of the casing 20.directly over the valve chamber 28. This plate in Fig. 2 has an admission passage 5| from the atmosphere to the valve chamber and thence to the suction chamber. In this passage is an open guide 52 carrying the stem 80 of a double valve, namely, the conical valve 5! adapted to seat at-the top of the passage 5i and the conical 'yalve 62 adapted to seat at the bottom of thepa'ssage. The stem 60 is shownas connected to a. lever 85 which is intermediateiy pivoted to disc 1|. This spring. therefore, tends to maintain the diaphragm in the elevated position shown in V Fig. 1, which results in the valve 8! engaging .the seat at the top of the passage 5!.

1 The diaphragm 12 is held in place by a casing 80 which rises above it and has at the bottom an annular flange tightly secured to the diaphragm and the plate 50. This casin has an outward flange ,atits upper end on which rests the margin of a diaphragm 82, this margin being clamped by the annular bottom flange oi the cap 88. Within the casing 80 is a transverse partition 8|, dividing the interior in upper and lower chambers. A compression spring 85 rests on this partition and at its upper end bears against the under face or the diaphragm 82 and tends to maintain it elevated.

Extending through the partition 86 in the easing area number of holes 9! normally closed by a check valve 82 consisting, in the form shown,

asa rubber button having a shank mounted in the partition and a head extending across the openings 8| and normally closing them. Throu h the partition beyond the region 01' the check valve 1 have also provided one small hole 95.

A suitable conduit, as shown as a pipe 90, connects the interior or the cap 88 above the diaphragm 82 with the discharge chamber 23 so that pressure in the'discharge chamber is constantly transmitted to the top of the diaphragm 82.v

. It results from the constructionldescribed that when the pressure in' the pipe 90 does not exceed the i'orceoi' the spring. 85, the parts remain in the position shown in Figs. 1 and 2 and the valve 6| is seated. When however, pressure in the pipe 1 '90 acting downwardly on the upper face of the diaphragm 82, plus a vacuum tendency from the suction chamber to pull the diaphragm downwardly, causes a greater downward iorce than the upwardforce oi the spring 85, the diaphragm moves downwardly. This compresses the enclosed "air beneath the diaphragmjso that such air that it is more than counterbalanced at its spring 185, the diaphragm 82 immediately returns to the,

position shown in Fig. 1, but this is not followed immediately by the return of the diaphragm I2 because the check valve 92 closes the passageway 9i and it takes an appreciable time for the com-' pressed air below the partition 94 to seep back through the small hole 85 into the space abov the partition. It results, therefore, that when the pressure in the pipe 90 having been once established is sumciently reduced, the double valve changes slowly from the position of closing the bottom of the passage 5i to the position of closing the top of it and during such interval the passage is left open so that air will be admitted from the outside to the valve chamber 28 and thence through the opening 29 to the upper portion 25 of the suction chamber. This admission of air continues for a sufficient length of time to allow the liquid in the suction pipe to dropor clear the pipe entirely 20 without disturbing the liquid in the portions 26 and 21 of the suction chamber.

As hereinafter more fully explained, the situation described occurswhen the impeller loses its prime and ceases to pump. liquid or establish proper pressure in the discharge chamber 28. When that situation does take place the mechanism described causes an air relief to the upper portion of the suction chamber to prevent siphoning and insures the retention of suflicient liquid in the suction chamber to re-prime the pump.

In Figs, 1 and 2, I have shown a screen cap I00 over the passage El and also a screen casing "ii on the under side of the plate 50 surrounding the valve mechanism. These screens prevent any extraneous matter reaching either valve' seat, thus insuring a tight seating 01 the valve 6| or $2 as the case may be.

vIn describing further the operation of my control mechanism, I call attention to the two diagrams, Figs. 3 and 4, which illustrate the essential parts of my double diaphragm system. In

these diagrams the diaphragm A, casing A'- and spring A-2 correspond to the diaphragm 82, the

upper portion of its enclosing casing and the spring 85 respectively. Similarly, B, .B and and 3-2 correspond to the diaphragm 12, the lower part of its enclosing casing-and the spring 75. The conduit C leading from the casing A to the casing B corresponds to openings in the partition 84; check valve D corresponds to the. check valve 92, and the small opening (1 in the check valve to the opening 95 in the partition 84. The

-, valve and'its immediate operating parts are designated by the same reference numerals as heretoiore.

Describing the operation with reference to the diagrams. -When the pumpstarts the impeller causes suction in the suction. chamber, water is drawn up the supply pipe, fills the suction space it from the position of Fig. 3 to the position of Fig. 4. This compresses the air in front of the diaphragm and operates diaphragm B which had been standing in the position of Fig. 3, so that it comes into position oi Fig. 4. This changes the vacuum-breaking valve almost instantly from 1 momentarily and without efiect the closed position of Fig. 3 to the closed position of Fig. 51, so that the suction is relieved only on the operation ,of the pump.

Now suppose the water being pumped becomes lower in the sump than the end of the suction pipe, a slug of air comes up the suction pipe, and travels down behind the water in the suction chamber to the impeller. This causes the impeller to lose its prime and it ceases to pump; the pressure in the discharge chamber drops; accordingly the spring A-2 behind the diaphragm A returns it to the position of Fig. 3. Diaphragm B, however, cannot return instantly on account of the small opening d in the check valve D between the two diaphragm cases, hence, diaphragm B returns gradually, but in doing so leaves the double valve in an intermediate open position for a material length of time. This opens the air vent to the suction chamber above the water in'the loop to the eye of the impeller and this satisfies the receding water in the suction pipe (assuming that there is no check valve or that it leaks) so that such receding water doe not siphon the water out of the loop.

In a short time compressed air above diaphragm B will have seeped back through the small hole d into the casing A and diaphragm B will return to the position of Fig. 8 and the vacuum breaking valve will be seated at its upper seat, thus closing the vent to the suction chamber.

Water is thus retained in the loop and the rotating impeller can pump the same. does pump it, the pressure is built up in the discharge chamber which operates to shift diaphragmA into position of Fig. 4 and this causes diaphragm B to move immediately to the position of Fig. 4, shifting the valve without substantially breaking of the suction. The parts thereafter continue in this position during normal operation of the pump.

With this vacuum breaking system no check valve is needed in the suction chamber, thus avoiding the difilculties encountered when such check valves are employed, such as leakage caused by wear or by foreign matter between the check valve and its seat (a weed, for instance, coming up the suction pipe) which prevents the check valve from closing. All operating parts of my improved vacuum breaking system are removed from the path of fluid flowing through the pump. 4

Figs. 5 and 6 illustrate another embodiment of my invention wherein the arrangement of diaphragms is substantially the same as in Figs. 1 and 2, but instead of the stem HI from the lower diaphragm operating a lever'to a double valve, I have provided a stem llll directly acted on by the diaphragm 12 and carrying a valve IH adapted to seat against the underside of a passage H3 and another valve H2 adapted to seat against the upper edge of that passage. These valves Ill and 2 therefore correspond respectively to the valves BI and 62 of the first embodiment, though they operate in the opposite direction thereto.

In the embodiment of Fig. 5, the opening to the atmosphere is by a passageway H5 leading to the space beneath the diaphragm 12. A suitable gauze partition H6 protects this passageway. The rest of the-partsshown in Figs. 5 and 6 are substantially the same as already described with reference to Fig. 1 and the same reference numerals apply.

In the operation of the control shown in Fig. 5, when sufiicient pressure passes through the pipe 90 against the upper diaphragm 82, this diaphragm, as heretofore stated, compresses the air above the partition 84 which passes through the small openings controlled by the check valve When it O2 and forces down the diaphragm 72 which causes the valve H2 to seat at the top of the passage ll3. This action takes place instantly when proper pressure is obtained. When the pressure is relieved the check valve 92 seats and the lower diaphragm can return to its upper position only slowly as the air passes through the small opening 95, with the result of a substantial interval after the valve H2 leaves its seat before the valve ill engages its seat.

It will be seen that whichever embodiment is employed, the air admission passage is normally closed; that as soon as pressure builds'up in the discharge chamber the valve shifts, opening the passage but immediately closing it,- and that it is maintained closed so long as the proper discharge pressure lasts. Then upon failure of this discharge pressure the valves return comparatively slowly to their original position and during this interval air is admitted to the upper part of the suction chamber and thereby preventing it being siphoned and insuring retention of sufil- .cient water-in the lower portion of the suction chamber to re-prime the pump.

I claim:

l. The combination with a pumphaving a suction conduit, automatically controlled means of admitting outside air directly to the conduit when the pump fails to prime.

2. The combination of a centrifugal pump having a chamber for retaining liquid in contact with the impeller of the pump, a suction conduit leading to said chamber, and automatic means to admit air from outside of the pump directly to a high point in the chamber between the impeller and suction conduit when the impeller fails to prime. p

3. The combination of an impeller pump having a suction conduit, means providing a passage from the external atmosphere directly to said conduit, a valve for controlling said passage, and means responsive to the pressure conditions on the discharge side of the pump for controlling said valve.

4. The combination of an impeller pump having a suction chamber with its lower portion in communication with the eye of the impeller, a suction conduit in communication with the upper portion of the chamber, and means responsive to a diminution of pressure in the delivery conduit to admit air from the outside directly to a high point of the chamber.

5. In an impeller pump, the combination, withv an impeller, of a casing having an impeller chamber and a chamber adapted to contain liquid in engagement with the impeller, a suction conduit leading to the last-mentioned chamber, and means dependent on the lack of priming for the impeller to automatically open an air vent to the upper portion of the latter chamber followed by an automatic but gradual closing of said air vent.

6. In an impeller pump, the combination with an impeller its casing, of a suction conduit thereto and a'dis'charge conduit therefrom, a passageway for air to the suction conduit, valve means for opening'and closing said passageway, and means responsive to a predetermined pressure in the discharge conduit to open and then immediately close said valve means, said means.

responding to a predetermined minimum in pressure in th discharge conduit to gradually close said valve means.

7. In a pump, the combination of an impeller, a suction conduit leading thereto, a discharge conduit leading therefrom. a diaphragm, a conduit for conveying pressure from the discharge conduit to the diaphragm, means providing a passageway for air to the suction conduit, valve means for controlling said passageway, and an operating connection between the diaphragm and valve means.

8. In a pump, the combination with an impeller,

9. The combination with a pump having liquidpropelling means between a suction conduit and a dischargeconduit, means providing a pairof bers, a conduit from the delivery side of the pump to the first chamber, means providing a passageway from the first chamber on the other side of its diaphragm to the second chamber on one side of its diaphragm, a check valve for controlling said passageway, a by-pass around the check valve independently thereof between the.

two regions which the check valve controls, a passageway for air leading to the suction conduit, and valve means for controlling said passageway and controlled by said second diaphragm.

13. The combination of a pump having an im-,

peller, a, suction conduit leading thereto, a delivery conduit leading therefrom, a pair of diai phragms located in individual chambers, a conduit from the delivery side of the pump to the first chamber, a conduit from the first chamber on the other side of said diaphragm to the secchambers each with a diaphragm, a conduit from I the discharge side of the pump to the first diaphragm, a conduit from the opposite side of the first diaphragm to the second diaphragm, a check valve in the last-mentioned conduit, a restricted passageway from the far side of the first diaphragm to the near side of the second diaphragm independent of the check alve,means providing an air passageway to the suction conduit, valve means for controlling said air passageway, and means whereby said valve means is controlled by said second diaphragm.

10. The combination, with a pump having an impeller and suction and discharge chambers, of a control device for preventing siphoning from the suction chamberif the pump fails to prime, saidpontrol device comprising two housings each divided by a diaphragm to produce four-internal chambers, the first control chamber being in communication with the discharge chamber of the pump, the second control chamber on the other side of the same diaphragm being in communication with the third control chamber, and the fourth control chamber on the far side of the second diaphragm being in communication with the suction chamber of the pump, a valve controlling admission of air to the suction chamber of the pump, and means actuated by the second diaphragm to operate said valve.

11. The combination, with a pump having an impeller and suction and discharge chambers, oi! a control device for preventing siphoning from the suction chamber if the pump fails to prime,

said control device comprising a housing divided by a diaphragm to produce two control chambers, the first control chamber being in communication with the discharge chamber of the pump, and the second control chamber being on the other side of the same diaphragm, a second housing having a diaphragm bounding a, third control chamber, the second and third control chambers being in communication with each other and their internal space being filled with fluid whereby movement of the first diaphragm under pressure from the discharge chamber of the pump may be communicated to the second diaphragm, springs acting on the two diaphragms in opposition to such movement, a valve controlling admission of air to the suction chamber of the pump, and means actuated by the second diaphragm to operate said valve.

12. The combination, with a pump having an impeller and a suction conduit leading thereto and a delivery conduit leading therefrom, of a pair of diaphragms located in individual chamond chamber on the pressure side of its diaphragm, a check valve for controlling said conduit, a restricted by-pass around the check valve independently thereof between the two regions which the check valve controls, a passageway for air leading to the suction conduit, a double valve for controlling said passageway, adapted to seat alternately against opposite ends of the passageway, and a driving connection between the nonpressure side of the latter diaphragm and said double valve, whereby predetermined pressure against the first diaphragm will immediately change the double valve from one seating to the other and the reduction of said pressure to a predetermined minimum will gradually change said valve from one seating to the other and intermediately leave the air vent open to the suction conduit.

14. In a pump, the combination with a pumping mechanism and suction and discharge conduits of a casing having a partition with an opening through it, a check valve for controlling said opening, there being a constantly open passageway through the partition independent of the check valve, a diaphragm in the casing on one side of said partition, a conduit from the discharge conduit to the side of said diaphragm distant from the partition, a diaphragm in the casing on the other side of said partition, means providing anair passageway to the suction conduit, a valve for controlling the same, and actuating means for the valve operated by the second diaphragm.

15. In a pump, the combination, with a pumping mechanism and suction and discharge conduits, of a casing having a partition dividing it into two chambers, there being an opening through the partition, a check valve for controlling said opening, there being a constantly open passageway through the partition independent of the check valve, a diaphragm in the first chamher, a conduit from the discharge conduit to the side of said diaphragm distant from the partition, a diaphragm in the second chamber, a compression spring in the first chamber opposing the approach of its diaphragm toward the partition, a compression spring in the second chamber opposing the recession of its diaphragm from the partition, means providing an air passageway to the suction conduit, and a valve for controlling the same operated by the second diaphragm.

16. In a pump, the combination, with thetwo chambers, a diaphragm in each chamber,

the first diaphragm'being subjected on one side to pressure in' the discharge conduit, a passageway from the first chamber'to the second chamber, a check valve therein opening toward the second chamber, a restricted by-pass between said chambers around the check valve, a lever operated by the second diaphragm, a passageway to said suction conduit having an opening with two opposed valve seats, a double valve seating on said respective seats, and an operating lever connected at one end to said second diaphragm and at the other end to said valve.

17. In a pump, the combination, with the means for propelling liquid from a suction conduit to a discharge conduit, of means providing two chambers, a diaphragm in each chamber, the first diaphragm being subjected on one side to pressure in the discharge conduit, a passageway from the first chamber to the second chamber, a check valve therein opening toward the second chamber, a restricted by-pass' between said chambers around the check valve, and a stem carried by the second diaphragm, two valves on the stem one above and the other below seats at opposite ends of an opening to the suction conduit of the pump, there being a passageway from the outside air into the space beneath the second diaphragm leading to said opening.

18. The combination, with a pump having a suction side and a pressure side, of means responsive to changes in pressure conditions in the pressure side for admitting air free from water directly to the suction side.

19. The combination with a pump, of a device responsive to a drop in pressure on the delivery side of the pump, and means controlled by said device for admitting air to the suction side of the pump from a source and through a passage independent of the delivery side.

20. The combination of a pump having a suction side and a pressure side and an intermediate impeller, there being no communication between the suction side and the pressure side other than through the impeller, and means responsive to changes in'pressure on the pressure side for admitting air to the suction side independently of the pressure side.

21. The combination of a pump having a suction side and a pressure side and a double-acting air-admitting pressure-responsive valve adapted to admit air from outside of the pump to the suction side thereof.

2-2. The combination of a pump having a suction side and a pressure side, there being an air passage to the suction side, said passage having two valve seats, two valves either of which when seated against either seat closes the passage, and means responsive to pressureconditicns on the pressure side of the pump for shifting the valves to open and then close the passage.

23. The combination of a. pump having a suction side and a pressure side, and an intermediate impeller, there being a passage from the atmosphere to the suction side, said passage having a double-faced valve seat, two connected valves either of which when seated against its seat closes the passage, and means responsive to a diminution in pressure on the pressure side of the pump for shifting the connected valves to open and then close the passage.

24. The combination of an impeller pump having an impeller, a suction chamber on one side thereof, a discharge, chamber on the other side thereof, and two additional chambers each containing a diaphragm, one of said diaphragms being responsive to pressure on the pressure side of the pump, a valve adapted to control the admission of air to the suction side of the pump and responsive to the other diaphragm, and operating means to communicate motion from the first diaphragm to the second, same means operating faster in one direction than the other.

25. The combination of a pump having a suction side and a pressure side, of three chambers, the first chamber being in communication with the pressure side and being bounded by a movable diaphragm, the third chamber having a diaphragm controlling a valve'for admission of air to the suction side, and the second chamber being bounded by the other sides of the two diaphragms mentioned and enclosing fluid out of communication with either the pressure side or the suction side of the pump.

' ALEXANDER. V. MUELLER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,461,622 LaBour July 10, 1923 1,472,560 Griffiths et al Oct. 30, 1923 1,757,282 Wood May 6, 1930 1,789,528 Lewis Jan. 20, 1931 1,978,400 Burks Oct. 30, 1934 1,993,267 Ferguson Mar. 5, 1935 1,997,418 Hornschuch et a1. Apr. 9, 1935 2,162,247 Dean et a1 June 13, 1939

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