US3381618A

US3381618A - Self-priming system for horizontal pumps

Info

Publication number: US3381618A
Application number: US633663A
Authority: US
Inventors: Pellegrino E Napolitano
Original assignee: Hudson Eng Co
Current assignee: PRIMAVAC SYSTEMS Inc A CORP OF NEW JERSEY
Priority date: 1967-04-10
Filing date: 1967-04-10
Publication date: 1968-05-07
Anticipated expiration: 1985-05-07

Description

y 1968 P. E. NAPOLITANO 3,381,618 4 SELF-PRIMING SYSTEM FOR HORIZONTAL PUMPS Filed April 10, 1967 3 Sheets-Sheet 1 v INVENTOR Pellegrino E. Nupolituno ymfimmgm ATTORNEYS y 7, 1968 P. E. NAPOLITANO 3,381,618

SELF-PRIMING SYSTEM .FOR HORIZONTAL PUMPS Filed April 10, 1967 5 Sheets-Sheet 2 FlG.2

INVENTOR Pellegrino E. Nopolimno TTORNEYS y 1968 P. E. NAPOLITANO 3,381,618

SELF-PRIMING SYSTEM FOR HORIZONTAL PUMPS Filed April 10, 1967 5 Sheets-Sheet 5 INVENTOR Pellegrino E.Nopolitano May/309 m ORNEYS United States Patent 3,331,618 SELF-PRIMING SYSTEM FOR HDRIZONTAL PUMPS Pellegrino E. Napolitano, Brooklyn, N.Y., assignor to Hudson Engineering Company, Hoboken, N..l., a corporation of New Jersey Continuation-impart of application Ser. No. 556,629, June 10, 1966. This application Apr. 10, 1967, Ser. No. 633,663

12 Claims. (Cl. 103-413) ABSTRACT OF THE DISCLOSURE During repriming of a horizontal pump by recycling liquid from the discharge conduit of the pump to the suction well for the pump, air is displaced from the suction well through an air vent. Air may also be bled from the impeller casing of the pump, preferably by a conduit leading to the upper portion of the suction well.

Cross-reference to related application This application is a continuation-in-part of my copending application Ser. No. 556,629 filed June 10, 1966.

Background of the invention The present invention relates to a self-priming pumping system. In the past, there have been many different devices developed to automatically prime a liquid pump when the pump runs dry due to an insufficient amount of liquid being present at the pump inlet and to prevent air from being introduced to the suction side of the pump. These devices are essential to the eificient operation of a pumping system, since, as is well known, once air is admit-ted to the suction passage in suificient quantities to allow the pump to exhaust the supply of liquid in the suction well, the pump no longer is able to maintain suction to pump the liquid. Consequently, the pumping operation would be stopped and the attention of an operator would be required if no automatic means for repriming the system is provided.

Summary of the invention In accordance with the present invention, a horizontal pump is primed by liquid from a suction well or reservoir located at the pump inlet. The suction well is normally supplied with liquid to be pumped by a suction line communicating with the liquid source of pumpage. A reprimin g valve is located in the pump discharge column to allow automatic recycling of liquid from the discharge line to the suction well when the pump has lost suction. A one-way check valve is positioned downstream from the repriming valve and allows fluid movement only in the downstream direction, and thus limits the quantity of liquid which may be recycled to that in the system between the repriming valve and the check valve. An air relief line with a one-way check valve connects the top of the suction well to the discharge column intermediate the first mentioned check valve and the repriming valve. Air is displaced from the suction well through the air relief line by the liquid which is recycled from the discharge column through the repriming valve tothe suction well. When a portion of the recycled liquid flows from the suction well into the pump inlet, the liquid will be pumped into the discharge column causing the repriming valve to close. If the pump is not fully reprimed, the repriming valve will thereafter again allow the same liquid to be recycled to the suction well. This recycling will continue in this fashion until the normal pumping cycle is restored.

The present invention is designed for autmoatically re- 3,381,618 Fatented May 7, 1968 priming single or multi-stage pumps employing any reasonable length suction line. In the event of loss of suction head due to the pump running dry, there is no danger of pump damage since the system will continue to reprime itself.

According to a further feature of the invention, an air relief line may vent air from the impeller inlet casing. It has been found that when liquid in the suction well is exhausted and air is sucked into the pump, an air lock may be formed between the inlet of the pump intake line and the impeller. This entrapped air may keep liquid from reaching that point in the impeller section of the pump where suflicient velocity can be imparted to it to force the liquid and the entrapped air into the discharge column. By the use of an air relief line extending through the casing of the pump impeller chamber, a path is provided for venting such entrapped air when the repriming fluid flows into the pump inlet.

It is a principal object of the present invention to provide novel apparatus for automatically repriming a pumping system which is fed by a suction intake line.

Another object of the present invention is to provide a self-priming pumping system for a horizontal pump capable of developing a suction head by recycling its priming fluid.

Another object is to provide a self-priming pumping system capable of repeatedly developing a suction head to draw liquid up through a relatively long suction line.

A further object of the invention is to provide a selfpriming pumping system wherein the component parts, including the pump, can be conveniently located to facilitate replacement or servicing, if necessary.

A still further object of the invention is to provide a self-priming pumping system that is rugged, positive in operation, and capable of pumping any sort of pumpage without becoming clogged or jammed.

An even further object of the present invention is to provide a self-priming pumping system for a horizontal pump that is compact, contains a minimum of moving parts, and is economical to manufacture.

The above and still further objects, features, and advantages of the present invention will become more apparent as this description proceeds.

Brief description of the drawing FIGURE 1 is a side elevational view, partially in section, illustrating one embodiment of the present invention.

FIGURE 2 is a vertical sectional view of the repriming valve employed as part of the present invention.

FIGURE 3 is a view similar to FIGURE 1 illustrating another embodiment of the invention with the pump being reprimed.

Description of the preferred embodiments Referring to FIGURE 1, reference numeral 4 designates a suction well or casing which acts as a reservoir for priming liquid 3. In normal operation, liquid 3 is supplied to the suction well through a suction line 40 which has its other end immersed in pumpage 2. A suction skirt 5 is positioned with its lower end adjacent the bottom of suction well 4, and is connected at its other end to an inlet 6 of a horizontal pump 20 which is driven by a motor 26. In the illustrated embodiment, suction skirt 5 has a curved upper portion, the lower inner surface of which is approximately level with the upper inner surface of the eye of the impeller, i.e., the horizontal inlet 6. A small aperture may be provided in the curved upper portion of the skirt 5 to function as an air bleed between this portion of the skirt and the top of the suction well 4. It is also possible to connect the vertically extending portion of skirt 5 to the pump inlet without elevating the upper portion of the skirt above the pump inlet 6, for example, by means of a 90 pipe elbow.

Pump 20 pumps fluid through an outlet 7, and a repriming valve assembly 30 to be described hereinafter into a discharge column 8. A one-way check valve 12 is positioned at the upper end of the discharge column *8 and connects the discharge column to a discharge line 42. A drain pipe 9 leads from valve 30 to the top of the suction well 4 so that liquid may be recycled in a manner to be described hereinafter to reprime the pump 20. The liquid in discharge column 8 and the quantity of liquid in repriming valve 30 above the level of drain pipe 9 are available to reprime the pump. Therefore, the discharge column 8 and the above mentioned portion of repriming valve 30 effectively function as a reservoir for repriming liquid. The volumetric capacity of this reservoir is at least sufficient to ensure that the quantity of liquid available to reprime the pump is sufiicient to fill the pump inlet, inlet 6, skirt and suction well 4 to a level corresponding to the level of the eye of the pump impeller.

An air relief conduit 10 leads from the top of the enclosed suction well 4 to the upper end of the discharge column 8 upstream from the check valve 12. A one-way check valve 11 in conduit 10 allows fluid movement only in a direction towards discharge column 8 to prevent liquid in column 8 from returning to the suction well via conduit 10.

FIGURE 2 illustrates a presently preferred repriming valve assembly 30. Valve assembly 30 basically comprises an inner casing 34 which has a lower portion in the shape of a venturi. The upper portion of the casing part of the reservoir section for the repriming liquid forms a cage structure for a plurality of peripherally spaced poppet valves 31 and the associated valve seats. A tube 35 is connected from each of four openings 32 in the throat of the venturi to a chamber formed by a cylinder 36 and a cooperating piston 38 which is connected to a valve 31 by a valve stem 50. A spring 37 between the head of each cylinder 36 and the associated piston 38 functions to normally bias each poppet valve 31 towards its open position which is shown by dashed lines in FIGURE 2. A jacket 39 surrounds the valve assembly and together with casing 34 forms an enclosed space 33 which is in communication with the drain pipe 9.

When liquid is being pumped during normal operation, the poppet valves 31 are maintained in their closed position by a pressure differential between the liquid in the upper portion of casing 34 and the liquid in cylinders 36, which pressure differential is of sufficient magnitude to overcome the bias of the springs 37. This pressure differential is established by the venturi in the lower section of casing 34 and control tubes 35 leading from openings 32 in the venturi to the cylinders 36. Since the tubes 35 communicate with the venturi, the static pressure in the venturi is present in the tubes, and in the cylinders 36. Due to the magnitude of the dynamic pressure factor flowing through the venturi which is proportional to the square of the velocity of the liquid, the static pressure in the venturi and hence in cylinders 36 is less than the static pressure acting upon the poppet valves 31 in the enlarged upper portion of casing 34. It is evident that the velocity of the liquid in the venturi is greater than the ambient velocity in the upper portion of casing 34 and therefore the pressure in conduits 35 is lower than the ambient pressure in the upper portion of the casing 34. Thus, a drop in pressure is created in cylinders 36 which permits pressure against valves 31 to force the valves 31 against their valve seats in opposition to the bias of springs 37. When the velocity of liquid flowing through the repriming valve reaches a predetermined low value, for example, when air is introduced ,into the system, and the pressure differential is sufiiciently reduced in magnitude, the bias of springs 37 is effective to open the poppet valves 31. When the poppet valves open, liquid may flow through the valve ports into the space 33 and then into drain pipe 9.

The operation of the FIGURE 1 embodiment will now be described. With the suction well 4 filled with liquid to a level above the pump inlet 6, liquid pumped into discharge column 8 by pump 20 creates a suction which draws more liquid into the suction well from suction line 40. As long as liquid flow continues, repriming valve 30 and check valve 11 remain closed.

However, if air or other gas enters the suction well and suction is lost, the pumping action stops when the liquid in the suction well is depleted. When the liquid flow from the outlet 7 of the pump stops, the pressure diferential holding the poppet valves 31 in their closed positions is reduced, and the valves are opened by springs 37. Liquid now flows out of valve assembly 30 and discharge column 8 through the ports associated with poppet valves 31, into space 33, and through drain pipe 9 back to the suction well 4. As the repriming liquid enters the suction well, air is displaced through air relief conduit 10 and check valve 11 into the now empty upper end of discharge column 8. When the repriming fluid from the suction well passes through the suction skirt 5 into the pump inlet 6, the pump 20 then draws the repriming liquid out of the suction well and pumps it into the discharge column 8. The flow of the repriming liquid from the pump outlet reestablishes the pressure differential which causes the poppet valves 31 to move to the closed position. Check valve 11 closes as the liquid enters the discharge column 8, and the air which has entered the discharge column is now forced through check valve 12 into discharge line 42. The removal of liquid from the suction well 4 reduces the pressure at the opening of suction line 40 so that liquid is drawn upward therein. When the repriming liquid is depleted, the cycle is repeated until suction is reestablished for the pump 20. Factors such as the length in diameter of the suction line 40 will determine how many times the pump will be reprimed before full pumpage flow is reestablished.

In one of the embodiments tested, a suction line 22 feet long and 14 inches in diameter achieved full discharge after three repriming cycles which tookplace in less than a minute.

FIGURE 3 illustrates another embodiment of the present invention in which parts corresponding to those of the FIGURE 1 embodiment are designated by like reference numerals. A suction skirt 58 establishes communication between the suction well 4 and an inlet 60 for a horizontal pump 61 which has an impeller 62. An air relief line 63 communicates between the uppermost portion of the impeller inlet casing 64 and the top of suction well 4. The remainder of the system is identical to that described in connection with the FIGURE 1 embodiment.

The purpose of the air relief line 63 will now be described. In the event that air enters the system, and the suction is interrupted; air may be taken in through skirt 58 and may fill the impeller eye chamber. Liquid which because of its density has been forced to the outer periphery of the vanes of the impeller and up into the outlet 7 may form a liquid seal between the inlet of skirt 58 and the impeller. The entrapped air may be unable to escape because not enough pressure can be built up upon the air to force it through the head of liquid in the outlet 7 and the repriming valve 30. Hence, even though the liquid level in suction well 4 may rise above the level of the impeller eye chamber, the entrapped air may prevent the repriming liquid from reaching that point in the impeller where velocity may be imparted to it to force fluid through outlet 7 up into the discharge column 8. Air relief line 63 provides a path by which the entrapped air in the pump inlet and in the impeller eye chamber may be vented to the upper portion of the suction well 4. From the suction well 4, the air may leave the system via the air relief pipe 10 and check valve 11.

The provision of the air relief line 63 reduces the time required to reprime the pump. In the absence of this line, small slugs of entrapped air may in time find their way through the liquid column into the discharge column 8, however, expulsion of the air in this manner is relatively slow.

A valve 65 is preferably provided in the air relief conduit 63 to adjust the rate of flow of air back to the suction well. By suitable adjustment of valve 65, the time period during a repriming cycle before the pump 61 will commence to pump liquid through outlet 7 may be regulated. For example, assuming that the inlet to suction line 40 has been elevated above the level of the liquid to be pumped, the pump 61 should not begin to expel liquid until the suction line 40 is again beneath the level of the liquid. Thus, assuming that the pump system is being emloyed to empty the hold of a ship; it is possible-that towards the end of the pumping operation, wave action may cause the level of the liquid in the hold to periodically fall below the level of the inlet to suction pipe 40. In this case, valve 65 may be adjusted so that the pump does not expel liquid through outlet 7 until the lower end of suction pipe 40 is again immersed in the liquid to be pumped.

While preferred embodiments of the invention have been shown and described, it will be understood that various changes and modifications may be made therein without departing from the scope and the spirit of the invention. For example, the air relief conduit 63 could lead directly to the upper end of the discharge column 8. Accordingly, it is intended to encompass all such changes and modifications as fall within the scope and spirit of the appended claims.

What is claimed is:

1. A self-priming horizontal pump system comprising a pump having an outlet and a horizontal inlet, a suction well defining a cavity at least partially below said inlet, a suction line means for introducing liquid to be pumped into said cavity to a level including the top of the inlet, conduit means positioned in said cavity with one end terminating below said inlet adjacent the bottom of said cavity and with its other end connected to said inlet, reservoir means having an upstream end and a downstream end, said upstream end of said reservoir means connected to said outlet of said pump, a one-way check valve located at said downstream end of said reservoir means enabling downstream fluid movement only, drain means interconnecting said cavity and said reservoir means, repriming valve means positioned upstream from said check valve and mutually cooperating with said reservoir means and said drain means to return liquid in said reservoir means to said cavity via said drain means, in response to a reduction in liquid flow from said pump, an air relief pipe connected from the top of said cavity to said reservoir means adjacent the upstream side of said check valve, and a second one-way check valve provided in said air relief pipe enabling fluid movement only in a direction towards said reservoir means, and wherein said drain means includes a housing surrounding a portion of said reservoir means and defining therewith an annular chamber, and conduit means interconnecting said annular chamber with said cavity.

2. A pump system according to claim 1, wherein said repriming valve means is located in said annular chamber.

3. A pump system according to claim 1, wherein the volumetric capacity of said reservoir means is at least suflicient to fill said horizontal inlet and said suction well up to the level of said horizontal inlet.

4. A self-priming horizontal pump system comprising a pump having an outlet and a horizontal inlet, a suction well defining a cavity at least partially below said inlet, a suction line means for introducing liquid to be pumped into said cavity to a level including the top of the inlet, conduit means positioned in said cavity with one end ter minating below said inlet adjacent the bottom of said cavity and with its other end connected to said inlet, reservoir means having an upstream end and a downstream end, said upstream end of said reservoir means connected to said outlet of said pump, a one-way check valve located at said downstream end of said reservoir means enabling downstream fluid movement only, drain means interconnecting said cavity and said reservoir means, repriming valve means positioned upstream from said check valve and mutually cooperating with said reservoir means and said drain means to return liquid in said reservoir means to said cavity via said drain means, in response to a reduction in liquid flow from said pump, an air relief pipe connected from the top of said cavity to said reservoir means adjacent the upstream side of said check valve, and a second one-way check valve provided in said air relief pipe enabling fluid movement only in a direction towards said reservoir means, and wherein said pump has an impeller casing, and further comprising conduit means connected to said impeller casing to vent air therefrom during repriming of said pump.

5. A pump system according to claim 4, wherein said conduit means comprise a conduit extending from said impeller casing to an upper portion of said suction well.

6. A self-priming horizontal pump system comprising a pump having an outlet and a horizontal inlet, a suction well defining a cavity at least partially below said inlet, a suction line means for introducing liquid to be pumped into said cavity to a level including the top of the inlet, conduit means positioned in said cavity with one end terminating below said inlet adjacent the bottom of said cavity and with its other end connected to said inlet, reservoir means having an upstream end and a downstream end, said upstream end of said reservoir means connected to said outlet of said pump, a one-way check valve located at said downstream end of said reservoir means enabling downstream fluid movement only, drain means interconnecting said cavity and said reservoir means, repriming valve means positions upstream from said check valve and mutually cooperating with said reservoir means and said drain means to return liquid in said reservoir means to said cavity via said drain means, in response to a reduction in liquid flow from said pump, an air relief pipe connected from the top of said cavity to said reservoir means adjacent the upstream side of said check valve, and a second one-way check valve provided in said air relief pipe enabling fluid movement only in a direction towards said reservoir means, and wherein said repriming valve means is associated with at least one port, a valve element movable between positions opening and closing said port, means defining a fluid chamber including a member connected to said valve element and movable in response to pressure in the fluid chamber, bias means acting on said movable member to bias said valve element towards the Open position, and means acting in response to a reduction in liquid flow from the pump outlet to create during normal operation a pressure diiferential overcoming said bias means to close said valve element.

7. A pump system according to claim 6, wherein said last mentioned means include a venturi, and a tube establishing communication between the narrow part of said venturi and said fluid chamber.

8. A pump system according to claim 7, wherein said movable member comprises a piston, and said bias means comprises a spring engaging said piston.

9. A self-priming horizontal pump system comprising a pump having a horizontal inlet and an outlet, a suction well having a cavity which is at least partially below said inlet, a downwardly extending suction line having its upper end opening into said suction well at a level above said inlet to supply liquid to said cavity, a suction skirt having its lower end positioned within said cavity below said inlet and having its upper end connected to said inlet, reservoir means for repriming liquid having an upstream end and a downstream end, said upstream end connected to said outlet of said pump, a repriming valve positioned at said upstream end of said reservoir means to open in response to a given condition of the liquid from said outlet, drain means connecting said repriming valve to said suction well for returning liquid in said reservoir means to said suction well, air relief means for venting air from said suction well to an upper portion of said reservoir means, said repriming valve comprising an annular casing forming a portion of said reservoir means, said annular casing being provided with a port in communication with said drain means, a valve element movable between positions opening and closing said port, a cylinder connected to said annular casing, a movable member in said cylinder forming therewith a fluid chamber, said movable member being connected to said valve element, bias means acting on said movable member to bias said valve element towards the open position, and means acting in response to said given condition of the liquid to establish a pressure differential between the liquid being pumped and the liquid in said fluid chamber to overcome said bias means to close said valve element.

10. A self-priming horizontal pump system according to claim 9, wherein said pump has an impeller casing, and further comprising conduit means connected to said impeller casing to vent air therefrom during repriming of said pump.

11. A self-priming horizontal pump system comprising a pump having an outlet and a horizontal inlet, a suction well defining a cavity at least partially below said inlet, a suction line means for introducing liquid to be pumped into said cavity to a level including the top of the inlet, conduit means positioned in said cavity with one end terminating below said inlet adjacent the bottom of said cavity and with its other end connected to said inlet, reservoir means having an upstream end and a downstream end, said upstream end of said reservoir means connected to said outlet of said pump, a one-way check valve located at said downstream end of said reservoir means enabling downstream fluid movement only, drain means interconnecting said cavity and said reservoir means, repriming valve means positioned upstream from said check valve and mutually cooperating with said reservoir means and said drain means to return liquid in said reservoir means to said cavity via said drain means, in response to a reduction in liquid flow from said pump, an air relief pipe connected from the top of said cavity to said reservoir means adjacent the upstream side of 'said check valve, and a second one-way check valve provided in said air relief pipe enabling fluid movement only in a direction towards said reservoir means, and the volumetric capacity of the cavity from the inlet to the bottom of said conduit means being substantially equal to the volumetric capacity of said reservoir from the reservoir check valve to the drain means.

12. A self-priming pump system comprising a pump having an outlet and an inlet, a suction well defining a cavity at least partially below said inlet, a suction line means for introducing liquid to be pumped into said cavity to a level including the top of the inlet, conduit means positioned in said cavity with one end terminating below said inlet adjacent the bottom of said cavity and with its other end connected to said inlet, reservoir means having an upstream and a downstream end, said upstream end of said reservoir means connected to said outlet of said pump, a one-way check valve located at said downstream end of said reservoir means enabling downstream fiuid movement only, drain means interconnecting said cavity and said reservoir means, repriming valve means positioned upstream from said check valve and mutually cooperating with said reservoir means and said drain means to return liquid in said reservoir means to said cavity via said drain means, in response to a reduction in liquid flow from said pump, an air relief pipe connected from the top of said cavity to said reservoir means adjacent the upstream side of said check valve, and a second oneway check valve provided in said air relief pipe enabling fluid movement only in a direction towards said reservoir means, the volumetric capacities of said reservoir, cavity, and conduit being such that after the cavity runs substantially dry and suction is lost substantially the entire liquid content of the reservoir must be fed to the cavity and conduit in order that the recycled content fills the conduit to a level to reach the pump inlet and be pumped again into the reservoir.

References Cited UNITED STATES PATENTS 1,080,917 12/1913 Lewis 103-113 2,744,469 5/ 1956 Schaefer 103-113 3,276,384- 10/1966 Boone et al 103-113 HENRY F. RADUAZO, Primary Examiner.