US3022738A - Pump systems - Google Patents

Description

Feb. 27, 1962 E. A. KRUTE 3,022,738

PUMP SYSTEMS Filed April 20, 1959 a Sheets-Sheet 1 Foal V4.20

END

1 FIG. Bantu/men EMU Everett A. Krute Inventor Bydal M Attorney E. A. KRUTE PUMP SYSTEMS Feb. 27, 1962 8 Sheets-Sheet 2 Filed April 20, 1959 A Horne Vere TU B By M O M Feb. 27, 1962 Filed April 20, 1959 E. A. KRUTE' 3,022,738

' PUMP SYSTEMS v a Sheets-Sheet :5

Everett A. Krute lnv entor Febp27, 1962 Filed April 20, 1959 E. A. KRUTE PUMP SYSTEMS 8 Sheets-Sheet 4 Everett A. Kruie Inventor Attorney Feb. 27, 1962 E. KRUTE PUMP SYSTEMS 8 Sheets-Sheet 5 Filed April 20, 1959 K .ll.

Inventor Everett A. Krute Feb. 27, 1962 E. AQ'KRUTE 3,022,738

PUMP SYSTEMS Filed April 20, 1959 8 Sheets-Sheet 6 4 I# l8 l9 3O 3O 64 3O 63 4864 ,1 55 R 52 lf4- R I 66 4 5467 R 60 68 4 55 32 Q 3l 32 3| 32 3! 59 sr g 37 59 3762 8-8 C-C I D-D Everett A. Krute Inventor By fl 2g Attorney Feb. 27, 1962 E. A; KRUTE 3,0

, 'PUMP SYSTEMS Filed April 20, 1959 a Sheets-Sheet 7 21 v I b 19 3! 59 3758 FIG. /7 m Everett A. Krufe I Inventor fl- Attorney "E. A. KRUTE Feb. 27, 1962 PUMP SYSTEMS 8 Sheets-Sheet 8 Filed April 20, 1959 0.056 Sec.

I20 I I I60 I50 H0 70 CRANK ANGLE, DEGREES PISTON TRAVEL (d) Inventor Everett A. Krute By :6 Attorney 3,li22,738 PUMP SYSTEMS Everett Archie Krute, 104 W. 44th St., Sand Springs, Okla. Filed Apr. 2%, E59, Ser. No. 807,699 Claims. (Ci. 103-4?) This invention relates to pump systems. It relates especially to hydraulicflly-actuated surgeless pumps. It relates more particularly to a hydraulic system for supplying and controlling fluid under pressure to hydraulic motors which drive pistons or plungers in a pump mecha msm.

Positive displacement pumps are widely used when it is desired to move a large volume of fluid, especially at high pressure. These pumps include the double acting piston type and the single acting plunger type. As is well known, in double acting piston pumps fluid is moved or delivered from the cylinder as the piston makes a forward stroke and also as it makes a rearward stroke. In single-acting plunger pumps, fluid is moved or delivered on the forward stroke only.

Positive displacement or reciprocating pumps, as they are sometimes known, of the past were coupled to and driven by steam cylinders. Some such steam driven pumps are still in service; however, most present positive displacement pumps are mechanically powered; i.e., the power end of the pump has a crank shaft (or eccentric) that changes rotary motion to reciprocating motion to drive the pistons or plungers in the pump. The reciprocating pistons drive the fluid to be pumped.

Mechanically operated pumps have a greater efficiency and a higher discharge pressure than steam pumps for any given size cylinder. However mechanically operated pumps have a serious problem. Pressure surge or pressure variation is a most serious problem. Pressure surge comes from the sudden increase of velocity given the fluid by the action of the piston. During the discharge stroke, the piston starts with a zero forward velocity, increasing to maximum at approximately (but not at) midstroke and decreasing to zero at the end of the stroke. The highest velocity for each piston of the pump would be at the top half of a true sine curve if it were not for the variation of the angularity eifect of the crankshaft on the piston rod or plunger rod. In order to have a non-pulsating flow of fluid from a piston or plunger pump, an infinite number of cylinders equally spaced around a crankshaft would be necessary.

Pressure surges have been studied and measured. Mathematical equations derived and solved to explain the phenomenon of pressure surges. Conclusions have been drawn that surges occurred because of the change in velocity of the fluid in the system.

There have been numerous articles written showing the magnitude of the pulsation problem. One recent article begins on page 115 of the May 12, 1958 issue of the Oil'and Gas Journal, 211 South Cheyenne Avenue, Tulsa, Oklahoma. Dampening devices have been designed to cut down pressure surges. While helpful in some cases, they are not the complete solution as they are only about 50% effective. In fact such devices are frequently detrimental in that they are subject to frequent failures.

It is thus clear that there is an urgent need for a positive displacement pumping system in which the pressure surges are eliminated or at least reduced to a point where they are not an operational problem. The present invention supplies such a system.

Accordingly one object of this invention is to provide a system in which pressure surges are essentially eliminated.

Another object of this invention is to provide a system to control the velocity of the pistons or plungers of the pump in such a manner that the sum of the velocities of such pistons or plungers are constant.

to hydraulic motors coupled to pistons or plungers in a pump mechanism. The pistons or plungers causing fluid to move in a system, operate in a controlled manner in which the sum of the velocities is constant. The velocity of the fluid being pumped or being discharged by the pistons or plungers is controlled in the same manner, i.e., at a constant velocity. Therefore there is essentially no pressure surge.

Other objects will be either disclosed or apparent from the following description taken in conjunction with the drawing in which:

FIG. 1 is a schematic view, partly in section, illustrating a hydraulically operated pump system embodying the principles of the present invention;

P16. 2 is a fragmentary view, partly in section, of a hydraulic control valve for controlling the amount of fluid going to hydraulic cylinders;

FIG. 3 is a view of the rotating cylinder of the hydraulic control valve illustrating its rectangular ports;

' FIG. 4 is a cross-sectional view of the rotating cylinder shown in FIG. 3 taken along line 4-4 and showing the spacing of the rectangular ports;

FIG. 5 is a fragmentary view of the non-rotating cylinder showing its arrangement of rectangular ports and passages;

FIG. 6 is a sectional view of the apparatus shown in FIG. 5 taken along line 6-6;

FIG. 7 is a sectional view of the apparatus shown in FIG. 5 taken along the line 7-7;

FIG. 8 is a sectional view of the apparatus shown in FIG. 5 taken along the line 3--8;

PEG. 9 is a sectional view of the apparatus shown in FIG. 5 taken along the line 99;

PEG. 10 is a schematic, partly sectionalized, drawing illustrating port position with respect to piston position;

FIG. 11 is similar to FIG. 10 and shows a second position of the valve and pistons;

FIG. 12 is similar to FIG. 10 and shows a third position of the valve and pistons;

PEG. 13 is similar to FIG. 10 and shows a fourth position of the valve and piston;

FIG. 14 is similar to FIG. 10 and shows a fifth position of the valve and pistons;

FIG. 15 is similar to FIG. 10 and shows a sixth position of the valve and pistons;

FIG. 16 is similar to FIG. 10 and shows a seventh posi-.

tion of the valve and pistons;

FIG. 17 is similar to FIG. 10 and shows an eighth position of the valve and pistons;

FIG. 18 is a curve plotting piston velocity against crank pin angle of rotation; and

FIG. 19 is a curve showing piston velocity against piston travel in a system of the present invention.

A preferred embodiment of this invention is illustrated in FIG. 1 which shows a hydraulically operated pump system embodying the principles of the present invention. Illustrated in FIG. 1 is pump 1 for pumping fluid, a hydraulic power drive 20 for driving pump 1, a hydraulic pump 38, a prime mover 42 for driving pump 38 and hydraulic valve means 29 for controlling the flow of fluid to the cylinders of hydraulic drive 20.

Pump 1, as illustrated, has a left hand pump cylinder 2, a right hand pump cylinder 3, a left hand pump piston 4 within cylinder 2 and a right hand pump piston 5 within cylinder 3. Each cylinder has two sets of valves. Cylinder 2 has left hand forward end suction valve 6, left hand rearward end suction valve 7, left hand rearward end discharge valve 11, and left hand forward end discharge,

Patented Feb. 27, 196.2 w

spasms valve 10. Cylinder 3 has right hand forward end suction valve 3, right hand rearward end suction valve 9, right hand forward end discharge valve 12 and right hand rearward end discharge valve 13.

Suction pipe 14 is connected to the suction side of pump 1 for carrying fluids thereto. A discharge pipe 15, for carrying fluids away, isconnected to the discharge side of pump-1.

Hydraulic power drive 20 has left hand hydraulic cylinder 21, left hand hydraulic piston 18 within hydraulic cylinder-21, right handhydraulic cylinder 22, and right hand hydraulic piston 19 within cylinder 22.

vA piston rod 16 connects the left hand pump piston 4 to the'left hand reciprocating non-differential hydraulic piston 18 and piston rod 17 connects the right hand pump piston to the right hand reciprocating non-differential hydraulic piston 19. Sealing means 23 and 26 are provided in pump 1 for piston rods 16 and 17 respectively. Sealing means 24 and 25 are provided in left hand hydraulic cylinder 21 and sealingmeans 27 and 28 are provided in right hand hydraulic-cylinder 2 2.

Conduit 33 connects the forward end or the left hand hydraulic cylinder 21 to afirst outlet 33A of hydraulic control valve 29 and conduit 34 connects the rearward end of the left hand hydraulic cylinder 21 to outlet 34A of the control valve 29.

Conduit 35 connects the forward end of the right hand hydraulic cylinder 22 to outlet 25A of the hydraulic control valve 29 and conduit 36 connects the rearward end of the right hand hydraulic cylinder 22 to outlet 36A of thehydraulic control valve 29.

Conduit 37 fluidly connects hydraulic pump 38 to inlet 37A of control valve 29 and delivers hydraulic fluid from hydraulic pump 38 to hydraulic control valve 29. Conduit '39 fluidly connects hydraulic fluid reservoir 44 to hydraulic pump 38 and is commonly referred to as a suction pipe. Conduit 41 fluidly connects fluid discharge outlet 41A of control valve 29 with hydraulic fluid reser- Von-46.

A prime mover 42, such'as an electric motor, is connected'to'hydraulic pump 33 through drive shaft 4-3. A drive mechanism-44 delivers power from the drive shaft 431:0 hydraulic control valve '29.

A pressure relief valve 45 is provided in pipe 37 between the hydraulic pump 38 and the hydraulic control valve 29 to protect the hydraulic system from excess pressures.

By pass valve 46 is provided in conduit 37 between hydraulic pump 38 and hydraulic control valve 29. The use of this valve will become apparent later in the description. 7

Referring now to FIGS. .2 and 3 it isseen that control valve 29 comprises a'valve housing 30, anon-rotating cylinder member 31, a rotating cylinder 3-2 and packing means 69.

Rotating cylinder 32 has rectangular passages 65, 66, 67 and 68. Passages 65 and 66 are longitudinally aligned and open 45 on the circumference. Passages 67 and 68 are likewise longitudinally aligned and open 45 on the circumference. The trailing edges 6ST and 661" of the openings of passages 65 and 66 are aligned with theleading edges 67L and 68L of the opening of passages 67 and 68. This is clearly shown in FIG. 4.

Referring in particular to FIGS. 5, 6, 7, 8.and 9 a description of non-rotating cylinder 31 will be given. There are three mating ports disposed laterally about nonrotating cylinder 31 for each passage 65, 66, 67 and 68 of rotating "cylinder 32. Laterally aligned with passage 65, when assembled, areports47, 56 and 57. FIG.- 6 shows 'port47 opening 135 of the inside circumference, ports 56 and 57 each has an opening of 45 of the inside circumference. ' Ports 47,56 and 57 are spaced 45 apart.

Referring to FIG. Spit is seen that ports-51, 6G and 61 are arranged "laterally similar to "ports 47, "56 and 57.

4 Ports 51, 6t) and 61 are aligned with passage 68 when assembled.

FIG. 7 shows ports 48, 49 and 58 are similar to the ports shown in FIG. 6 but have been rotated When assembled ports 4-8, 49 and 58 aligned with passage 66.

FIG. 9 shows ports 52, 53 and 62 laterally arranged similar to ports 49, 48 and 58. When the device is assembled ports 52, 53 and 62 alignwith passage 68 of rotating cylinder 32. In other words a plane perpendicular to the longitudinal axis of cylinder 32 which -bisects thepassage 65 in cylinder 32 for example, bisects ports 47, 56 and 57.

It should be noted that the longitudinal dimension of ports 47,56, 5'7, 69, 48, 49, 58, 52, 53, 62, 51 and 61 should be as great or greater than the longitudinal dimensions of passages 65, 66, 67, 68 of rotating cylinder 32. in this instance, passages 65, 66, 67 and 68 are of the same size and shape. Of course ports 47, 56, 57, 60, 48, 49, 58, 52, 53, 62, 51 and 61 can be of the same longitudinal dimensions and passages 65, 66, 67 and 63 may be of greater longitudinal dimension than such ports. In other words the desired metering may be accomplished by precision of the ports or by precision of the passages.

Passageway 54 fluidly connects ports 48 and 56; passageway 55 fluidly connects ports 52 and 60; passageway 59 fluidly connects ports 62 and 58, passageway 6.3.fluidly connects ports 49 and 57, passageway 64 fluidly connects ports 53- and 61, and passageway 5t fluidly'connects ports 47 and 51.

The design of the constant area of the ports within the hydraulic control valve 29 in connection with the reciprocating non-differential hydraulic cylinders Hand 22 is a unique system. Hydraulic pump 38 delivers a constant volume of fluid to the hydraulic valve 29 which meters the hydraulic fluid to the hydraulic cylinders 21 and 22 thereby controlling the acceleration and deceleration of the hydraulic pistons 13 and 19. The summation of these piston speeds is a constant which is of prime importancc as will later become apparent.

One cycle or the hydraulic system is illustrated-in FIGS. 10 through 17. Sections A-A, B-B, C-C and 13-1) of eachfigure aresections through each of the ports at-the same rotational position of rotating cylinder 32 with respect to non-rotating cylinder 31. Sections AA, B-B, C-C, and D--D in FIGS. 10 through 17 are section views'taken similarly as FIGS. 6, 7, 8 and-9 respectively at various rotational positions.

FIG. 10 shows the start of the cycle with the left hand hydrauliopiston 18 at the middle of the left hand hydraulic cylinder 21 and the right hand hydraulic piston 19 at the rearward end of hydraulic cylinder 22.

Section 13-13. FIG. 10-shows passage 66 of rotating cylinder 32 and ports 58 and 48 of non-rotating cylinder 3i fullzopen allowing a maximum amount of hydraulic fluid to pass from delivery pipe 37 through pipe 33 to the forward end of the left hand hydraulic cylinder 21 driving the left hand hydraulic piston 18 at a maximum speed toward the rear of the cylinder. The left hand hydraulic piston 18 is in'turn forcing hydraulic fluid from the rearward area of the left hand hydraulic cylinder 21 through pipe 34, through thefull open passage 65 of hydraulic control valve 29 as shown in section AA, FIG. 10 through the discharge pipe 41 to the reservoir 46. At this same instant, section C-C shows passage 67 closed so that no hydraulic fiuid is passing to the right hand hydraulic cylinder 22 and no hydraulic fluid is passing to the right hand cylinder 22 and no hydraulic fluid is being discharged as theports are-closed as shown in section D-D, FIG. 10.

In FIG. 11, rotating cylinder 32 has revolved one-eighth of a turn in a clockwise direction from the position .as shown in FIG. 10.

Section B-B, FIG. 11 shows the passage 66 of rotating cylinder '32 half "closed allowing only-one-half of thedrivingLhydraulicfluid-to pass from the delivery pipe.

37 through pipe 33 to the forward end of the left hand hydraulic cylinder 21 thus slowing the left hand hydraulic piston 18 to half speed. The left hand piston 18 forces the hydraulic fluid from the rearward area of the left hand hydraulic cylinder 21 through pipe 34 through half open passage 65 of rotating cylinder 32 as shown in section AA, FIG. 11 through discharge pipe 41 to the reservoir 40.

Section DD, FIG. 11 shows passage 68 of rotating cylinder 32 half open allowing half of the hydraulic fluid to pass from delivery pipe 37 through pipe 36 to the rearward end of the right hand hydraulic cylinder 22 thus allowing the right hand hydraulic piston to move forward at half speed. The right hand piston 19 forces the hydraulic fluid from the forward area of the right hand hydraulic cylinder 22, through pipe 35, through half open passage 67 of rotating cylinder 32 section C-C, FIG. 11 through discharge pipe 41 to reservoir 40.

In FIG. 12 the rotating cylinder 32 has revolved oneeighth of a turn in a clock-wise direction from the position as shown in FIG. 11.

Section BB, FIG. 12 shows that passage 66 of rotating cylinder 32 closed stopping the flow of hydraulic fluid through pipe 33 to the forward end of the left hand hydraulic cylinder 21 thus stopping the rearward movement of the left hand hydraulic piston 18, thus the flow of hydraulic fluid has stopped through pipe 34.

Section DD, FIG. 12 shows that passage 68 of rotating cylinder 32 is full open allowing the maximum amount of hydraulic fluid to pass from delivery pipe 37 through pipe 36 to right hand hydraulic cylinder 22 driving the right hand hydraulic piston 19 at a maximum speed toward the front of the cylinder. Right hand hydraulic piston 19 is in turn forcing hydraulic fluid from the forward area of the right hand hydraulic cylinder 22 through pipe 35, through the full open passage 67 of rotating cylinder 32 as shown in section CC, FIG. 12, through discharge pipe 41 to reservoir 40.

In FIG. 13 rotating cylinder 32 has revolved one-eighth of a turn in a clock-wise direction from the position as shown in FIG. 12.

Section BB, FIG. 13 shows the passage 66 of rotating cylinder 32 half open allowing half of the driving hydraulic fluid to pass from the delivery pipe 37 through pipe 34 to the rearward end of the left hand hydraulic cylinder 21 thus allowing the left hand hydraulic piston 18 to move forward at half speed. The left hand hydraulic piston 18 forces the hydraulic fluid from the forward-area of the left hand hydraulic cylinder through pipe 33, through the half open passage 65 of rotating cylinder 32, as shown in section A--A, FIG. 13 through the discharge pipe 41 to the reservoir 40.

Section DD, FIG. 13 shows passage 68 of rotating cylinder 32 half closed allowing only half of the hydraulic fluid to pass from the delivery pipe 37 through pipe 36 to the rearward area of the right hand hydraulic cylinder 22 thus slowing the right hand hydraulic piston to half speed. The right hand hydraulic piston 19 forces hydraulic fluid from the forward area of right hand hydraulic cylinder 22, through pipe 35, through the half open passage 67 of rotating cylinder 32, as shown in section C-C, FIG. 13 through the discharge pipe 41 to the reservoir 40.

In FIG. 14 the rotating cylinder 32 has revolved oneeighth of a turn in a clock-wise direction from the position as shown in FIG. 13.

Section B--B, FIG. 14 shows that passage 66 of rotating cylinder 32 is full open allowing the maximum amount of hydraulic fluid to pass from delivery pipe 37 through pipe 34 to the rearward area of left hand hydraulic cylinder 21 thus driving left hand hydraulic piston 18 at a maximum speed toward the forward end of the cylinder. Left hand hydraulic piston 18 is in turn forcing hydraulic fluid from the forward area of left hand hydraulic cylinder 21, through pipe 33 through the full open passage 65 of rotating cylinder 32, as shown in section A--A FIG. 14 through the discharge pipe 41 to the reservoir 40.

Section C-C, FIG. 14 shows that passage 67 of rotating cylinder 32 is closed stopping the flow of hydraulic fluid through pipe 36 to the rearward end of the right hand hydraulic cylinder 22, thus stopping the forward motion of right hand hydraulic piston 19. The flow of hydraulic fluid has stopped through pipe 35 as passage 68 of rotating cylinder 32 is closed as shown in section DD, FIG. 14.

In FIG. 15 rotating cylinder 32 has revolved one-eighth of a turn in a clock-wise direction from the position as shown in FIG. 14.

Section BB, FIG. 15 shows passage 66 of rotating cylinder 32 half closed allowing only half of the hydraulic fluid to pass from delivery pipe 37 through pipe 34 to the rearward end of left hand hydraulic cylinder 21 thus slowing the left hand hydraulic piston 18 to half speed. Left hand piston 18 forces hydraulic fluid from the forward area of left hand hydraulic cylinder 21, through pipe 33, through the half open passage 65 of rotating cylinder 32 as shown in section A--A, FIG. 15 through discharge pipe 41 to the reservoir 40.

Section DD, FIG. 15 shows passage 68 of rotating cylinder 32 half open allowing half of the hydraulic fluid to pass from delivery pipe 37 through pipe 35 to the forward area of right hand hydraulic cylinder 22, thus allowing the right hand hydraulic piston to move rearward at half speed. Right hand hydraulic piston 19 forces hydraulic fluid from the rearward area of the right hand hydraulic cylinder 22, through pipe 36, through the half open passage 67 of rotating cylinder 32, as shown in section C-C FIG. 15 through discharge pipe 41 to reservoir 411.

In FIG. 16 the rotating cylinder 32 has revolved oneeight of a turn in a clock-wise direction from the position as shown in FIG. 15. I

Section BB, FIG. 16 shows passage 66 of rotating cylinder 32 closed stopping the flow of hydraulic fluid through pipe 34 to the rearward area of the left hand hydraulic cylinder 21. This stops the forward motion of the left hand hydraulic piston 18, thus the flow of hydraulic fluid has stopped through pipe 33. At this point passage 65 of rotating cylinder 32 is also closed as shown in section AA, FIG. 16.

Section DD, FIG. 16 shows the passage 68 of rotating cylinder 32 full open thus allowing the maximum amount of hydraulic driving fluid to pass from the delivery pipe 37 through pipe 35 to the forward area of right hand hydraulic cylinder 22 thereby driving the right hand hydraulic piston 19 rearward at a maximum speed. The right hand hydraulic piston is in turn forcing hydraulic fluid from the rearward area of the right hand hydraulic cylinder 22, through pipe 36, through the full open passage 67 of rotating cylinder 32 as shown in section C-C, FIG. 16 through discharge pipe 4 1 to reservoir 41).

In FIG. 17 rotating cylinder 32 has revolved one-eighth of a turn in a clockwise direction from the position shown in FIG. 16.

Section B--B FIG. 17 shows the passage 66 of rotating cylinder 32 half open allowing half of the driving hydraulic fluid to pass from the delivery pipe 37 through pipe 33 to the forward area of the left hand hydraulic cylinder 21, thus allowing the left hand hydraulic piston to move rearward at half speed. The left hydraulic piston 13 forces hydraulic fluid from the rearward area of the left hand hydraulic cylinder 21, through pipe 34, through half open passage 65 of rotating cylinder 32 as shown in section AA, FIG. 17 and through the discharge pipe 41 to the reservoir 40.

Section DD, FIG. 17 shows passage 68 of rotating cylinder 32 half closed allowing only half of the driving hydraulic fluid to pass from the delivery pipe 37 through pipe 35 to the forward area of the right hand hydraulic cylinder 22 thus slowing the right hand hydraulic piston spaagrss 19tohalf:speed. The right hand hydraulic piston forces hydraulic fluid from the rearward area'of the right hand hydraulic cylinder 22,-through pipe 36, through half open passage 67 of rotating'cylinder 32 as shown in section C-C, .FIG. 17 through the discharge pipe 4-1 to reservoir 44!. This completes the illustration of eight positions of rotating cylinder 32 and the corresponding positions of pistonsltian'd 191during a cycle-which again begins in FIG.:10.

Since the left hand pump piston 4 is connected to left handihydraulic piston .18 bypistonrod 16 and right hand pump .piSiOntS is connected to right handhydra-ulic piston 19 by piston rod 17, pump pistons 4 and :5 move in the same manner asthe hydraulic: pistons 18 and 19.

Attention iscalled to the fact that hydraulic pistonslS and 19 show 'a'full stroke in FIGS. 10 through. 17. If bypass valve 46 is opened soithat half of the hydraulic fluid pumped by the hydraulic pump 38 is allowed to pass to reservoir '40 the hydraulic pistons 18, 1%, then would have only enough hydraulic fluid to make half a stroke. Therefore'the length of the stroke can be adjusted from zero movement to its maximum movement.

Referring to FIG. 1 operation of the pump fluid end 1 will become apparent.

As the left hand pump piston 4 moves rearward (down in FIG. 1), a pressure is built up in the rearward chamber (lower chamber in FIG. 1) of the left hand pump cylinder 2 causing suction valve 7 to close and discharge valve 11 to open allowing fluid to pass to discharge pipe 15. A reduced pressure having been created in the-forward chamber (upper-chamber in FIG. 1) of the left hand pump" cylinder 2 causes suction valve 6 to open allowing fluidto pass from suction pipe 14 into the left hand forward chamber (upper chamber in FIG. 1) of pump cylinder'2. When the left hand pump piston reverses and starts a forward motion (upin FIG. 1), a pressure is built up in the forward chamber of the left hand pump cylinder 2 causing suction valve 6 to close and discharge valve 10 to open allowing fluid to pass'to discharge pipe 15. A reduced pressure having-been created in the rearward (lower) chamber of the left hand pump cylinder 2, the discharge valve 11 closes and suction valve 7 opens allowing fluid to pass into rearward (lower) chamber of the left hand pump cylinder 2.

The operation of the right hand pump cylinder 3 is identical to the operation of the left hand pump cylinder 2.

FIG. [8 illustrates a typical velocity curve of the pistons of -a conventional duplex double-acting piston pump plotted for one complete cycle (1.0 sec.) of the pump. Thescale of the Crank Angle '(w) is from the forward end dead center of the crank pin, noted as degree, in both directions, clock-wiseand counterclock-Wise, to the rearward end dead center, noted as 180 degrees. The Piston Velocity scale for this example may be assumed to be feet per second (f.p.s.).

The velocity'curve of the No. 1 piston is indicated by a heavy, solid line and starts at Odegree while the velocitycurve of the No. 2 piston isa heavy, dashed line and starts at 90 degrees and is moving toward the rearward end of the pump.

Attention should he called to the'ofl-balance shape of the curve between 0 to 180, but the similarity of the two curves of 0 to 180 and 180 to 0". Notice that the highest velocity of 1.0 fps. is at about 80 in each curve. This high velocity is reached when the angle between the'connecting rod and the radius of the crank is at 90.

The light solid line is a summation'of the velocities of the two pistons, and the dashed-dotted line is the mean flow, meaning if the peaks and valleys of the summation curve Where leveled oli'the summation curve would fall on the mean'fiow line.

These curves show the undesirable features, surge or pulsation, in the duplex double-acting piston pump. This shows the .peaksiabovesandthe valleys below their teen Flow line and especially the very high peak-when the No.1 piston is at 45 and the No. 2 piston is'at 4-5". The velocity peak starts at 1.0 f.p.s., approaches 1.6 f.p.s., thendrops back to 1.0 f.p.s. within 0.22 second.

Pressure changes within a pump are directly proportional to the velocities within the pump. Pressure changes in a cluplcx double-actingpiston pump vary about 50%; that is for example a pump with a working pressure :of 1335p.s.i. the change in pressure is from .1003 .p.s.i. to 1668 psi. or 665 p.s.i. change within each cycle of the pump. These 665 psi. are in effect blows whichcause fatigue and eventual failure and a costly shutdown of a pumping system.

In contrast to FIG. 18, FIG. 19 illustrates the velocity and mean flow curves of two hydraulic pistons using the system of this invention. 'In FIG. 19 the velocity of the hydraulicpistons of two non-differential hydraulic cylinders is plotted for one complete cycle (1.0 second). The Piston Travel (d) scale is the distance of the piston travel.

The Piston Velocity scale for this example may be assumed to be feet per second (f.p.s.), thesame'as FIG. .1.

The velocity curve of the No. 1 piston is indicated by a heavy solid line and starts at 0, the forward end of the cylinder. The voice ty curve of the No. 2 piston is a heavy dashed line and starts at 0.5, the middle of the cylinder. The proper relative position of pistons 1 and 2 is automatic in the use of this system. All that is necessary is to have the hydraulic system properly filled.

Attention is called to the linear p ston velocity curves. The curves show that the pistons begin to move at the ends of the cylinders and accelerate at a constant rate to the middle of the cylinders where their maximum ve locity of 1.3 fps. is reached. The pistons will then begin to decelerate at a constant rate until its velocity is O at the end of the cylinder. W.th two cylinders, one piston one half of the cylinder length out of phase, the summation of the velocities of the two pistons'equala constant of 1.3 f.p.s. at all times in a cycle.

If this hydraulic mechanism is used in place of the standard crank mechanism to operate a fluid pump,-the fluid being discharged would have a constant discharge velocity, therefore a constant pressure, without damaging pulsation or surge.

A duplex double acting piston pump was driven by two hydraulic drive pistons which were operated under the system of this invention. There were essentially no variations in discharge pressure. With the use of this system damaging pulsations are therefore eliminated.

The description and drawfngs herein are given for the purpose of illustration and not for limitation. .It is possible to produce still other embodiments without departing from the inventive concept herein disclosed, and it is desired that only such limitations be imposed on the appended claims as are stated therein.

The invention claimed is:

1..A valve for metering driving fluid comprising an outer housing; a non-rotating cylinder adapted to fit within sa'd housing; arotating cylinder adapted to rotatable fit within said non-rotating-cylinder; first, second, third and fourth longitudinally spaced lateral passages through said rotating cylinder, said passages having rectangular openings of 45 in the periphery of said rotating cylinder and opposite openings of each passage being diametrically opposite, the openingsof said first and second passages being longitudinally. aligned, the openings of said third and fourth passages being longitudinally aligned, thetrailing edges of the openings of said first and second passagesbeing longitudinally aligned'with the.leading edges of the openings of-said third andlfourth passages; first,.sccond, third, and.fourthlongitudinally spaced .sets of lateral ports in'said'non rotat 11g cylinder, each set. of ports'comprising three :ports spaced 45 from. each :otherslaterally, two ports each having an opening of 45 inner peripheryof said. non-rotating cylinder the third port haviugmnopening of the. ports in. said first and said third set be ng similarly disposed laterally and diametrically opposite from the lateral spacing of the ports in said second and fourth sets of ports; first communicating means connecting the 135 port of said first set of ports with the 135 port of said third set of ports and the exterior of said housing; second means fluidly communicating the 135 port of said fourth set of ports and the exterior of said housing; third means fluidly communicating one 45 port of said first set with the longitudinally aligned 45 port of said second set and the exterior of said housing; fourth means for fluidly communicating the other 45 ports of said first and second sets of ports and the exterior of said housing; fifth means fluidly communicating one 45 port of said third set of ports with said longitudinally aligned 45 port in said fourth set of ports and the exterior of said housing; sixth means fluidly communicating the other 45 ports of said third and fourth set of ports and the exterior of said housing.

2. An apparatus as defined in claim 1 which includes means to rotate said rotating cyl nder uniformily.

3. An apparatus as defined in claim 1 which includes means to vary the rate of flow of driving fluid to said valve.

4. A valve for metering driving fluid comprising an outer housing; a non-rotating cylinder adapted to fit Within said housing; a rotating cylinder adapted to rotatably fit within said non-rotating cylinder; a first and second rectangularly shaped indentation spaced 180 center to center from each other about the circumference of said rotating cylinder; th rd and fourth rectangular shaped indentations spaced 180 center to center from each other about the circumference of said rotating cylinder; fifth and sixth rectangular shaped indentations spaced 180 center to center from each other about the circumference of said rotating cylinder; seventh and eighth rectangularly shaped indentations spaced 180 center to center from each other about the circumference of said rotating cylinder; each indentation being in and covering 45 of the circumference of said rotating cylinder; first and second rectangular shaped ports spaced 90 center to center on the inner periphery of said non-rotating cylinder; third and fourth rectangular shaped ports spaced 90 center to center on the inner periphery of said non-rotating cylinder; each port being in and opening 45 on the inner periphery of said non-rotating cylinder; a first means connecting said first and second rectangular shaped indentations; a second means connecting said third and fourth rectangular shaped indentations; a third means connecting said fifth and sixth rectangular shaped indentations; a fourth means connecting said seventh and eighth rectangular shaped indentations; a fifth means connecting said first rectangular shaped port with the exterior of said outer housing; a sixth means connecting said second rectangular shaped port with the exterior of said housing; a seventh means connecting said third rectangular shaped port with the exterior of said housing and an eighth means connecting said fourth rectangular shaped port with the exterior of said housing.

5. A pump system consisting of first and second hydraulically operated double-acting cylinders fitted with reciprocating hydraulic driving pistons, first and second fluid pump cylinders fitted with reciprocating fluid pump pistons, drive means connecting said first hydraulically operated driving piston with said first fluid pump piston, and With drive means connecting said second hydraulically operated drive piston with said second fluid pump piston, a valve for metering driving fluid comprising an outer housing; a non-rotating cylinder adapted to fit within said housing; a rotating cylinder adapted to rotatably fit Within said non-rotating cylinder; first and second rectangularly shaped indentations spaced 180 center to center from each other about the circumference of said rotating cylinder; third and fourth rectangularly shaped indentations spaced 180 center to center from each other about the circumference of said rotating cylinder; fifth and sixth rectangular shaped indentations spaced 180 center to center from each other about the circumference of said rotating cylinder; seventh and eighth rectangularly shaped indentations spaced 180' center to center from each other about the circumferonce of said rotating cylinder; each indentation being in and covering 45 of the circumference of said rotating cylinder; first and second rectangular shaped ports spaced center to center on the inner periphery of said nonrotating cylinder; third and fourth rectangular shaped ports spaced 90 center to center on the inner periphery of said non-rotating cylinder; each port being in and opening 45 on the inner periphery of said non-rotating cylinder; a first means connecting said first and second rectangular shaped port; a second means connecting said third and fourth rectangular shaped port; a third means connecting said fifth and sixth rectangular shaped port; a fourth means connecting said seventh and eighth rectangular shaped port; a fifth means connecting said first rectangular shaped port with the exterior of said outer housing; a sixth means connecting said second rectangular shaped port with the exterior of said housing; a seventh means connecting said third rectangular shaped port with the exterior of said housing and an eighth means connecting said fourth rectangular shaped port with the exterior of said housing; a hydraulic fluid pump to deliver hydraulic fiuid under pressure to the system, reservoir means for storage of hydraulic fluid.

References Cited in the file of this patent UNITED STATES PATENTS 2,274,224 Vickers Feb. 24, 1942 2,282,977 Mast May 12, 1942 2,402,300 Shimer June 18, 1946 2,486,079 Tucker Oct. 25, 1949 2,528,131 Garretson Oct. 31, 1950 2,592,940 Monoyer Apr. 15, 1952 2,696,082 Fouron et al. Dec. 7, 1954 2,876,704 Collion et al Mar. 10, 1959 2,925,718 Switzer Feb. 23, 1960

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