US2974600A - Pumping system - Google Patents

Description

March 14, 1961 c. H. RYSTROM 2,974,600

PUMPING SYSTEM Filed April 18, 1956 2 Sheets-Sheet 1 ATTORNEYS.

March 14, 1961 c. H. RYSTROM 2,974,600

PUMPING SYSTEM Filed April 18, 1956 2 Sheets-Sheet 2 7 V EN T 0R.

ATTORNEYS.

description when read in connection with United States Patent 2,974,600 PUMPING SYSTEM Charles H. Rystrom, 325 Linden St., Winnetka, Ill. Filed Apr. 18, 1956, Ser. No. 579,117 8 Claims. (Cl. 103-11 This invention relates to a pumping system and more particularly to an apparatus for obtaining full operating pressure on start-up and quick cut-off in pumping of fluids.

"In pumping systems for applications such as oil burners, it is important that there be a momentary delay and then the oil supplied at full pressure and in full volume at the start and the flow of oil out off quickly during stopping to eliminate dribbling at the nozzle and to insure that oil will not accumulate after the air blower has stopped. There are other applications wherein it is important that no fluid be supplied until it is available at full pressure and full volume and that upon stopping of the pump the supply of fluid will be cut off sharply before the pump pressure drops an appreciable extent. Attempts to accomplish these results by the use of electrically operated valves have been made, but the apparatus required is relatively expensive and in many cases does not accomplish the results as well as is desirable.

It is accordingly one of the objects of the present invention to provide -a pumping system in which control is effected solely by pressure of the pumped fluid through simple and inexpensive pressure responsive valves to effect a momentary delay then full pressure on start-up and quick cut-off.

Another object is to provide a pumping system in which the pressure responsive valves are built into the pump itself andoperate positively and'directly in response to pump pressure.

According to one feature of the invention, fluid supplied to a pressure responsive discharge valve is relieved during start-up so that the discharge valve will remain closed until the pump is up to full volume and full pressure and a pressure responsive valve is included in the relief connection controlled by the pump pressure to be closed when the pump reaches full pressure and full volume. In shutting down the pressure responsive valve opens as soon as the pump volume drops to a slight extent below full ready volume and allows the discharge valve to close quickly while the fluid is still at substantially full pressure.

The above and other objects and features of theinvention will be more readily apparent from the following the accompanying drawings, in which:

Figure 1 is a longitudinal section through a two-stage pump embodying the invention;

Figure 2 is a flow diagram of the pump of Figure 1;

Figure 3 is a section similar to Figure l with parts in elevation of a single-stage pump; and

' Figure 4 is a flow diagram of the pump of Figure 3.

Q The pump, as shown in Figure 1, comprises a main body casing which is generally cup-shaped with its open end closed by a closure plate 11. A driving shaft 12 extends through the closure plate and is supported by suitable bearings 13 therein to drive the two pumps within the casing. The closed end wall of the main casing 10 is provided witha discharge passage 14 for connection 2,974,600 Patented Mar. 14, 1961 to an oil burner nozzle or other apparatus to be supplied with fluid and with a passage 15 for connection to a pressure gauge. Centrally of the wall there is provided a relief passage 16 which opens through the wall, as shown.

The outer surface of the end wall of the main casing 10 is provided with annular grooves for cooperation with a pressure responsive discharge valve. As shown, the valve includes a valve body formed with an outer annular groove 17 communicating with the passage 15 and with a fluid connection indicated at 52 through which fluid under pressure from the second stage pump is supplied to the valve. An intermediate the discharge passage 1-4.

The pressure responsive discharge valve is completed 'by a flexible diaphragm 19 which is urged to seating position against the grooves by an adjustable spring 21 normally to isolate the several grooves from each other when the valve is in its closed position. When the pressure supplied to the valve through the connection 52 acting throughout the annular groove 17 exceeds the pressure exerted by the spring 21, the diaphragm 19 will be flexed against the spring first to establish communication between the groove 17 and the groove 18 and as the pressure increases further to open the passage 16 to the grooves 17 and 18 to relieve excess pressure.

The spring 21 is mounted in a cup member 22 which is surrounded by a cylindrical filter element 23 for filtering the incoming fluid. The filter element may be held in expanded position by a light coil spring 24 and is enclosed by a cup-shaped casing 25 which fits sealingly against the main casing 10. Fluid from a suitable source is supplied to the casing 25 through an inlet conduit indicated diagrammatically at 26 to be filtered by passing through the cylindrical filter 23 before it enters the pumps.

In the embodiment of Figures 1 and 2 there are two pumps forming a so-called two-stage unit. Both pumps are of conventional gear type construction, as shown, although it will be understood that any desired type of pumps could be employed. As best seen in Figure 2, the first-stage pump comprises a ring gear 27 and a pinion 28 drivably mounted on the shaft 12 and meshing with the ring gear at one side. A crescent-shaped blocking plate 29 is mounted between the gears at their opposite sides and an inlet connection 31 extends to an inlet port ad- -jacent to one end of the crescent and at one side of the meshing point between the gears. An outlet connection 32 extends to a point at the opposite end of the crescent and .on the opposite side of the meshing point between the charge from the first pump through the discharge conduit 32. As shown, the valve comprises a flexible diaphragm 33 urged in one direction to valve closing position by a relatively heavy spring 34. Fluid is supplied from the pump to the opposite side of the diaphragm into an annular groove 35 which is normally isolated by the diaphragm from a relief passage 36. The annular groove 35 communicates with a restricted relief connection 37 which is designed to pass a volume of fluid equal to about of the pumps capacity at the pressure for which the unit is designed. As shown in Figure 1, the relief valve is formed by a pair of discs 38 and 39 which are clamped together in face-to-face relation against the closed end of the casing 10 with the diaphragm 33 between them. The discs 38 and 39 are grooved or controlled to provide the several flow passages described above and to be described hereinafter in cooperation with additional discs which make up the pump assembly. As shown, the opening in groove 18 communicates with which the spring 34 is mounted is in free communication through a groove 41 with the interior of the main casing which serves as an oil reservoir and the relief passage 16 communicates with the same opening so that any oil flowing through the relief passage 16 when the discharge valve is fully open will be returned to the interior of the casing 10.

The diaphragm 33 serves as a part of the second pressure responsive valve which controls communication between an annular groove 42 and a passage 43. A light spring 44 normally urges the diaphragm to a position to close off the passage 43, but the spring is made extremely light to exert a force on the order of one ounce so that a very low pressure in either the groove 42 or the passage 43 will cause the valve to open and permit flow therethrough. The spring 44 may be omitted entirely and serves mainly to help purge air from the system on initial start-up. To close the valve, the surface thereof opposite to the groove 42 and passage 43 is connected through a passage 45 with the groove 35 of the first pressure responsive valve to receive fiuid from the first pump. Thus, when the volume delivered by the first pump exceeds the capacity of the bypass 37 pressure will be exerted on the diaphragm to seat it against the discharge opening of the connection 43 to close this connection to flow throughout.

The second-stage pump is constructed similarly to the first-stage pump, as described above, with an annular ring gear 46, a pinion 47 drivably mounted on the shaft 12, and a fixed crescent 48. Fluid is supplied to the inlet of the second-stage pump through an inlet passage 49 which is in open communication with the space within the main casing 10 which serves as a fluid reservoir 51. The discharge connection from the second pump, as shown at 52, leads to the annular groove 17 of the discharge valve with which the relief connection 43 also communicates. The annular groove 42 of'the relief valve is in open communication through a passage 53 with the reservoir 51 and as shown the connections 16, 36, and 37 also discharge into the reservoir 51. The quantity of fluid retained in the reservoir 51 is limited by an overflow connection 54 leading from the upper part of the reservoir to the source of supply, such as a tank, indicated at 55 in Figure 2.

As shown in Figure l, the shaft 12 is sealed by a ring 56 around the shaft and sealed against the end closure 11 of the main casing as by an O-ring 57. A sealing ring 58 secured to the shaft rides against an annular sealing surface on the ring 56 to prevent leakage of oil around the shaft.

To relieve any pressure of oil against the seal a connection 59 is provided from a point adjacent to the ring 56 leading to the inlet space 61 of the second-stage pump, as shown in Figure 1. Thus pressure on the seal is relieved and is prevented from building up to the point where leakage would tend to occur.

In a typical installation for oil burner use the firststage pump is designed to deliver about twenty gallons per hour at a relatively low pressure and the second-stage pump is designed to deliver about twelve gallons per hour at high pressure. The relief passage 37 is designed to pass about sixteen gallons per hour at the delivery pressure of the first pump and the spring 34 is calibrated to open the relief passage 36 when the delivery pressure of the first pump reaches about 35 p.s.i. As pointed out the spring 44 is an extremely light spring and will bypass oil through the relief passage 43 to the reservoir 51 at substantially zero pressure when there is no oil pressure acting on the second valve.

In starting up when the pumps are being driven and until the speed is built up to the point where the first pump is delivering more than sixteen gallons per hour, all of the oil pumped by the first pump will flow through the relief passage 37 to the reservoir 51 so that no pressure will be exerted on the second valve and the relief .4 passage 43 will bypass oil at an extremely low pressure back to the reservoir. Thus at this time the oil pumped by the second pump will flow back through the relief passage 43 and the discharge valve will remain closed with no oil being delivered to the discharge connection 14. When the speed of the pumps has built up to the point where the first pump is delivering a volume of oil in excess of sixteen gallons per hour, pressure will be built on the second pressure responsive valve to close the relief passage 43. At this time, pressure from the second pump will build up in the annular groove 17 until the discharge valve opens and allows oil to flow into the groove 18 and out the discharge conduit 14 at full pressure and full volume. If the first pump delivery builds up to the full twenty gallons per hour rated capacity, the diaphragm 33 will flex upward against the spring 34 and bypass excess oil through the passage 36 into the reservoir 51. Similarly, if the pressure delivered by the second pump to the discharge valve increases sufliciently the discharge valve will open the bypass 16 and return excess oil to the reservoir 51. The reservoir 51 retains a predetermined quantity of oil at atmospheric pressure, any excess being returned to the tank through the overflow conduit 54.

When the pumps are stopped by cutting off the driving motor their speed will gradually reduce and the volume of oil delivered will gradually reduce. When the volume delivered by the first pump falls to sixteen gallons per hour or less, pressure acting on the second pressure responsive valve will fall and the relief passage 43 will again open to bypass oil from the discharge valve. As soon as pressure on the discharge valve is relieved, it will be closed quickly by the spring 21 to cut off the fiow of oil to the nozzle sharply and before the delivery pressure has dropped substantially below the desired value. Thus in operation of the system, full operating pressure on start-up and quick cut-oft are obtained with a very simple valve mechanism which can be incorporated easily into the pump itself and which operates solely in response to fluid pressure. Figures 3 and 4 illustrate an alternative construction for a single-stage pump operation, parts therein corresponding to like parts in Figures 1 and 2 being indicated by the same reference numerals, plus 100. In this construction, the pump outlet connection 132, in addition to leading to the groove 135, leads through a restricted connection 165 to the groove 117 of the discharge valve. The connection 145 to the second pressure responsive valve is isolated from the groove by an annular land 166 so that in the closed position of the first pressure responsive valve no oil can flow through the passage to the second pressure responsive valve. A restricted relief connection 167 communicates with the passage 145 to prevent blocking of the second pressure responsive valve and is designed to pass a very small quantity of oil on the order of two gallons per hour.

In this construction, for a normal oil burner operation, the restricted passage is designed to pass about fourteen gallons per hour at 130 p.s.i. pressure and the pump is designed to deliver about twenty-one gallons per hour at a pressure in excess of 130 p.s.i. The spring 134 is designed to hold the first relief valve closed until the pressure in the annular groove 135 reaches 130 p.s.i. and the spring 144 is designed, as in the embodiment of Figures 1 and 2, to permit the second pressure responsive valve to open the relief passage 143 when the pressure therein is on the order of one ounce p.s.i. The discharge valve may be designed to open at a pressure of from about 75 to 120 p.s.i., as in normal oil burner operation.

In starting up this construction until the pump speed is sufficient to produce a delivery in excess of fourteen gallons per hour, all of the fluid pumped will flow through the connection 165 and the relief connection 143 past the second pressure responsive valve to the reservoir 151.

When the volume" exceeds fourteen -gallonsgp'er hour, pressure will build up in the groove 135 to open the first pressure responsive valve and permit oil toflow through the passage 145 to the second pressure responsive valve. As soon as pressure is applied to the second pressure responsive valve, it will close quickly to close off the relief passage 143. Pressure in the groove 117 acting on the discharge valve will then open the discharge valve so that fluid will be delivered through the discharge conduit 114 at full pressure and full volume.

In shutting down the unit as the pump speed drops, so that the pump delivery is not greater than fourteen gallons per hour, the pressure in the groove 135 will drop below 130 psi. and the first pressure responsive valve will close. As soon as the first valve is closed, the pressure acting on the second pressure responsive valve will be relieved through the restricted passage 167 and the second pressure responsive'valve will again permit flow at low pressure through the relief passage 143. This will relieve the pressure in the groove 117 so that the discharge valve will close quickly before the pump pressure has dropped below the desired delivery pressure and before the air blower has stopped running. It will be noted that in this construction, because the first pressure responsive value cuts off pressure from the second pressure responsive valve while the pump pressure is still at a relatively high value, the discharge valve is allowed to close before the pump pressure falls below the desired delivery pressure to effect the quick cut-off.

While two embodiments of the invention have been shown 'and described herein, it will be understood that they are illustrative only and not to be taken as a definition of the scope of the invention, reference being bad for this purpose to the appended claims.

What is claimed is:

1. A pumping system comprising a first pressure responsive valve, a spring acting on one side of the valve urging it to closed position, means to supply fluid under pressure to the other side of the valve to urge the valve open, means defining a restricted relief passage communicating with said means to pass a predetermined volume of fluid, the valve being opened by fluid pressure when the volume delivered thereto by said means exceeds said predetermined volume, a pressure responsive outlet valve, a spring urging the outlet valve closed, a discharge connection to the outlet valve, means to supply fluid under pressure to the outlet valve to act on the outlet valve in a direction to open it, a second pressure responsive valve, a relief connection from the outlet valve leading to the second pressure responsive valve and closed when the second pressure responsive valve is closed and open when the second pressure responsive valve is open to bypass fluid tending to open the outlet valve, and means connecting the second pressure responsive valve to said other side of the first named valve to close the second pressure responsive valve when the volume delivered to said other side of the first named valve exceeds said predetermined volume.

2.. A pumping system comprising a first pressure responsive valve, a spring acting on one side of the value urging it to closed position, a fluid pump connected to the other side of the valve to supply fluid under pressure thereto to urge the valve open, means defining a restricted relief passage communicating with the value to pass a predetermined volume of fluid, the valve being opened by fluid pressure When the volume delivered by the pump exceeds said predetermined volume, a pressure responsive outlet valve, 8. spring urging the outlet valve closed, a discharge connection to the outlet valve, means connecting the pump to the outlet valve to supply fluid under pressure to the outlet valve tending to open it, a second pressure responsive valve, a relief connection from the last named means to the second pressure responsive valve, the second pressure responsive valve normally passing fluid to relieve the pressure on the outlet valve, and means 6 connecting the second pressure responsive valve to the first pressure responsive valve to close the second pressure responsive valve when the volume delivered by the pump exceeds said predetermined volume.

3. A pumping system comprising a normally closed outlet valve adapted to open in response to a predetermined fluid pressure supplied thereto, means to supply fluid under pressure to the outlet valve, a relief connection communicating with said means, a pressure responsive valve in the relief connection normally communicating at one side with the relief connection and permitting fluid flow through the relief connection and closing in response to fluid pressure supplied to the other side thereof, means to supply fluid under pressure to said other side of the pressure responsive valve to close the valve, and a restricted relief passage communicating with said other side of the pressure responsive valve to pass a predetermined volume of fluid, the pressure responsive valve being closed when the volume delivered thereto exceeds said predetermined volume.

4.'A pumping system comprising a first fluid pump having its inlet connected to a source of supply, means defining a container for fluid, a restricted passage connecting the outlet of the first pump to said container to pass a predetermined volume of fluid to the container, a second pump having its inlet communicating with said container, a normally closed valve connected to the outlet of the second pump adapted to open in response to a predetermined outlet pressure, a relief passage connected to the outlet of the second pump, a pressure responsive valve in the relief passage normally passing fluid at low pressure, and a connection from the outlet of the first pump to the pressure responsive valve to close the valve when the volume pumped by the first pump exceeds said predetermined volume.

5. A pumping system comprising a first fluid pump having its inlet connected to a source of supply, means defining a container for fluid, a restricted passage connecting the outlet of the first pump to said container to pass a predetermined volume of fluid to the container, a pressure responsive relief valve connected to the outlet of the first pump to bypass fluid in excess of said predetermined volume to the container, a second pump having its inlet communicating with said container, a normally closed pressure responsive valve connected to the outlet of the second pump adapted to open in response to a predetermined outlet pressure, a relief connection to the outlet of the second pump, a pressure responsive valve in the relief connection normally passing fluid at low pressure therethrough, and a connection from the outlet of the first pump to the pressure responsive valve to close the valve when the volume pumped by the first pump exceeds said predetermined volume.

6. A pumping system comprising a pump having its inlet connected to a source of supply of fluid, a pressure responsive outlet valve normally closed and adapted to open in response to a predetermined fluid pressure, a restricted connection from the pump outlet to the outlet valve to pass a predetermined volume of fluid to the valve, a relief connection from the valve, a pressure responsive valve in the relief connection normally passing fluid therethrough at low pressure, and means connecting the pump outlet to the pressure responsive valve to close the valve when the volume supplied by the pump exceeds said predetermined volume.

7. A pumpingsystem comprising a pump having its inlet connected to a source of supply of fluid, a pressure responsive outlet valve normally closed and adapted to open in response to a predetermined fluid pressure, a restricted connection from the pump outlet to the outlet valve to pass a predetermined volume of fluid to the valve, a relief connection from the valve, a pressure responsive valve in the relief connection normally passing fluid therethrough at low pressure, a connection from the pump outlet to the pressure responsive valve to supply fluid 7 8 thereto to close the. valve, and a second n'oimally closed References Cited in the file of this patent pressure responsive valve in the last named connection UNITED STATES PATENTS to be opened When thevolume dehvered by the pump 2,461,991 Logan Feb 15 1949 exceeds Sald predetefmmed 5 2,582,753 Herbelleau Jan. 15, 1952 8. The construction of claim 7 m which the second 2,655,109 Walker (1143,1953 pressure responsive valve includes a relief connection to 2, 2,477 Logan et 1 Dag 15, 1953 by-pass fluid to the source. 2,751,847 Erikson June 26, 1956

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