Valve structure and method of operation

Jan. 29, 1957 κ. r. lung 2,779,352

VALVE STRUCTURE AND METHOD OF OPERATION Original Filed Jan. 29, 1952

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ATTORNEYS

United States Patent Office

2,779,352

Patented Jan. 29, 19S7

2,779,352

VALVE STRUCTURE AND METHOD OF OPERATION

Kenneth R. Lung, Dayton, Ohio, assignor to The Tait Manufacturing Company, a corporation of Ohio

Original application January 29,1952, Serial No. 268,750. Divided and this application November 1, 1952, Serial No. 318,938

Claims. (Cl. 137—490)

This invention deals with valves, particularly flow controlling or pressure reducing valves, and especially to the use of such valves in connection with pumping systems. This application is a division of my copending application Serial No. 268,750, filed January 29, 1952, and assigned to the same assignee as this application.

A type of pumping system which is widely used, particularly for supplying water for domestic use in rural areas, comprises a centrifugal pump having its suction pipe extending into a well and with a jet pump mounted in the suction pipe. This arrangement has proved quite satisfactory for the purpose of lifting and pumping water and is extensively employed for deep wells where the only other expedient for removing water would be to mount the pumping unit deep in the well within, say, eighteen to twenty-two feet of the surface of the water.

While the combination of a centrifugal pump and a jet pump is satisfactory, as mentioned, for the purpose of lifting and pumping water while enabling the centrifugal pump to be mounted at ground level, there are, nevertheless, certain faults to be found in the operation of such systems. The principal fault with which the present invention is concerned comes about because the centrifugal pump generally delivers its discharge to a storage tank and is periodically started and stopped according to the level in the storage tank. Because of the intermittent operation of the pumping system, the pressure against which the pump works will vary from a minimum pressure when the liquid level in the storage tank is low and the pump has just started, to a predetermined maximum pressure which will obtain in the storage tank after the pump has been operating for a period of time and the tank has become filled to a predetermined level.

The water for operating the jet in systems of this nature is taken from the discharge side of the pump so that a portion of the pump discharge is continuously recirculated through the jet. When the pump is working against a varying head, as described above, the amount of water so supplied to the jet will vary between a relatively small amount when the pump pressure is low to a relatively large amount when the pump pressure is high. Heretofore, the jet pump has been designed so that it operates most efficiently at some pump pressure between the maximum and minimum values thereof, and at all other pump pressures, the jet pump is permitted to operate inefficiently. This, of course, entails loss of power and less efficient pumping action than could otherwise be obtained.

The particular object of the present invention is to provide a pumping system of the nature described in which the jet pump will always operate at the same high degree of efficiency.

A still further object is the provision in a pumping system of the nature described of an arrangement for maintaining the pump pressure substantially constant at all times, so that there is substantially constant pressure supplied for operating the jet pump.

A still further object is the provision of a pumping system of the nature referred to wherein the discharge pres10 sure of the centrifugal pump is maintained substantially constant at all times even against the varying head in the storage tank, and which maintenance of the constant pressure is accomplished with substantially no loss of pumping efficiency.

A particular object of this invention is the provision of a greatly improved pressure regulating valve for incorporation in a pumping system which will operate to maintain a substantially constant discharge pressure at the outlet side of the pump.

_ It is also a particular object of this invention to provide a pressure regulating valve for the purpose referred to which is extremely small and inexpensive to manufacture.

It is also an object of this invention to provide an improved method of operating a pumping system of the nature referred to which leads to a higher degree of efficiency.

These and other objects and advantages will become more apparent upon reference to the following description taken in connection with the accompanying drawings, in which:

Figure 1 is a view of a pumping system arranged according to this invention and illustrated more or less diagrammatically; and

Figure 2 is a transverse section through the pressure regulating valve forming the principal feature of this invention.

Referring to the drawings somewhat more in detail, in Figure 1 there is illustrated a centrifugal pump at 10 adapted for being driven by electric motor 12. Pump 10 may be a single stage or multi-stage centrifugal pump of any of several well-known types. The suction side of the pump, is connected by down pipe 14 with a source of water in a well, and it will be understood that the extreme lower end of pipe 14 will preferably comprise a foot valve or check valve, according to well-known practices.

Incorporated in pipe 14 is a jet pump comprising jet 16 and venturi 18. This arrangement operates in a well-known manner to drive water upwardly in down pipe 14 at least to that point where it can be drawn upwardly into centrifugal pump 10 by the suction thereof.

The discharge side of pump 10 is connected by conduit 20 with a storage tank 22. Fluid for operating the jet pump is supplied to jet 16 via conduit 24 which branches off conduit 20 and is thus subjected to pump discharge pressure.

Downstream of branch 24 in conduit 20 there is mounted according to this invention a pressure regulating valve 26.

Valve 26 is illustrated in detail in Figure 2, wherein it will be seen to comprise a body part 28 open at the top and having secured thereto a bonnet portion 30, as by screws 32. Body part 28 comprises a first outer annular chamber 34 that communicates with inlet 36 that is attached in Figure 1 to the conduit leading between valve 26 and pump 10.

The body portion also comprises an inner central chamber 38 separated from outer chamber 34 by the upstanding cylindrical wall portion 40 that defines a port 42 at its upper end. The chamber 38 communicates with outlet 44 of valve 26, and which will be seen in Figure 1 to be connected with the conduit leading from valve 26 to storage tank 22.

Valve 26 may also be provided with a port 46 communicating with chamber 38 for the purpose of mounting a pressure indicator in the system. The outer chamber 34 may also have an auxiliary port 48 which is employed for the purpose of priming the system, should it become necessary.

Mounted over the open top of body 28 is a resilient

2,770,362 diaphragm 50 having its periphery clamped in sealing relationship with the upper edge Of body 28 by bonnet 30 and also by the annular metallic element 52. Element 52 also serves to clamp another diaphragm 54 against a downwardly facing annular surface on bonnet 3®, so that the space in bonnet 30 above diaphragm 50 and beneath diaphragm 54 is completely sealed off from the space in the bonnet above diaphragm 54. Diaphragm 50 comprises a metallic plate .56 about which the rubber part of the diaphragm is molded and which plate defines a central port 58 in the diaphragm opening from inner chamber 38 in the valve body into the chamber within the bonnet between the said diaphragm, and which chamber is indicated by reference numeral 69.

Diaphragm 50 also comprises a small port or passage 62 that communicates chamber 60 above the diaphragm with the annular cuter inlet chamber 34 of body 28.

Port 58 in the center of diaphragm SO is adapted for being variably restricted and closed by a needle-pointed valve member 64, which is shouldered at 66 to engage the under side of diaphragm 54, and which has a part extending through the diaphragm and expanded at 68 so as to clamp the plunger 70 to the diaphragm and in.sealing relation therewith.

Plunger 70 is reciprocably mounted in sleeve 72 pressed into the upper portion of bonnet 35 and a spring 74 presses downwardly on plunger 70 to urge it together with valve member 64 toward diaphragm 5® for closing port 58 thereof. It will be noted that plunger 7® is hollow, and this permits spring 74 to be relatively long, so that substantial movement of plunger 70 can be had without any great change in pressure thereon.

The upper end of spring 74 engages a shoulder on adjustable abutment 76 which is connected with screw 78 extending out through the top of bonnet 3® and adapted for being locked in position by lock nut SO.

The described valve operates automatically to maintain a predetermined minimum pressure in inlet chamber 34 in body 28 during operation of pump 10, and thereby to maintain substantially constant pressure in conduit 24, so that jet 16 of the jet pump always operates at maximum efficiency.

The operation of the valve in maintaining this constant pressure is as follows:

Assuming the pumping system to be at rest, with the pump 10 not being driven, then diaphragm 50 is held against port 42 by valve member 64 which is influenced by spring 74. This effectively isolates inlet chamber 34 from outlet chamber'38. If the pump now starts, pressure will be delivered to the inlet chamber 34, and this will act upwardly on the annular area of diaphgram 5® which is immediately over chamber 34. This pressure will also bleed through port 63 into chamber 60 and stand in the said chamber exerting a thrust downwardly on diaphragm 50 over its entire upper surface. This latter thrust, being greater than the upward thrust on the diaphragm, the diaphragm will remain in its port closing position.

As the pressure in inlet chamber 34, and, therefore, in chamber 69, rises, a point will come when the said pressure in chamber 68 will reach the point at which diaphragm 54 will yield upwardly, due to the thrust thereon being great enough to compress spring 74. The space above diaphragm 54 is connected with the atmosphere through port 82, and it will be apparent that the yielding of diaphragm 54 will take place at a predermined pressure.

As soon as diaphragm 54 commences to yield upwardly, valve member 64 will move upwardly and open port 53. This will release some of the fluid from chamber 60, and, inasmuch as port 58 is larger than port 62, a pressure drop will take place in chamber 60 that will be accompanied by upward movement of diaphragm 50. This upward movement of diaphragm 50 will move port into position where it will be at least restricted by valve member 64, arid at the same time outlet chamber 33 will be connected with inlet chamber 34, thereby providing for discharge of water through the valve from pump 10 to storage tank 22.

It will be apparent that with the upper surface of diaphragm 54 being exposed to the atmosphere, the tendency will be for diaphragms 54 and 50 to assume the positions at which a substantially constant pressure will prevail in chamber 60. Since chamber 60 will be maintained under that pressure by fluid, flow from the inlet chamber of the valve through port 62, and then from chamber 60 through port 58 to the outlet chamber, it will be apparent that there will be substantially a constant pressure drop from chamber 68 to the inlet chamber 34. It will, therefore, be evident that the pressure that is maintained in inlet chamber 34 is substantially constant, and that the diaphragms 50 and 54 will automatically flex to vary the communication between the inlet chamber and the outlet chamber to adjust the rate of fluid flow therebetween, so that the said constant pressure in the inlet chamber will .be maintained. The maintaining of the said inlet pressure leads to the beneficial results referred to above in the efficient operation of the jet pump.

The use of the pressure reducing valve according to this invention is to be greatly preferred over the use of a simple restriction in conduit 20 because with, a simple restriction, as much loss of power occurs when the pump is discharging against a high pressure, as occurs when the pump is discharging against a low pressure, whereas with the pump of the present invention, when the pressure in the storage tank rises, the pressure regulating valve will offer less and less restriction to fluid flow.

The valve of the present invention is also to be preferred over conventional pressure regulating or pressure reducing valves on account of its extremely compact size and simple construction. In spite of the compact size of the valve, however, it will be noted that flow passages therethrough are large and adequate, and that, therefore, a valve large enough for the usual pumping system of the type described will be quite small dimensionally and thus can readily be incorporated in the pipe system without any difficulties.

It will be understood that this invention is susceptible to modification in order to adapt it to different usages and conditions, and, accordingly, it is desired to comprehend such modifications within this invention as may fall within the scope of the. appended claims.