US3837765A

US3837765A - Pump

Info

Publication number: US3837765A
Application number: US00385885A
Authority: US
Inventors: I Weise; E Purfurst
Original assignee: Anderson Greenwood and Co
Current assignee: Anderson Greenwood and Co
Priority date: 1971-04-08
Filing date: 1973-08-06
Publication date: 1974-09-24
Anticipated expiration: 1991-09-24

Abstract

A pump having a lost motion connection between the power piston and the pumping piston so that the stroke of the pumping piston may be varied without changing the stroke of the power piston, a restriction in the outlet from at least one end of the power cylinder to control the rate of movement of the power piston, and a control valve as a subcombination having relationships between the valve member and ports defined to prevent stopping of the pump in a mid position. This abstract is neither intended to define the invention of the application which, of course, is measured by the claims, nor is it intended to be limiting as to the scope of the invention in any way.

Description

finite States Patent 1191 [111 3,837,765

Weise et a1. Sept. 24, 1974 [54] PUMP 2,862,478 12/1958 Staats... 417/403 X [75] Inventors: Irvin B weise, Bella r est H. 3,348,803 /1967 Churchill, Jr. 91/313 X Purfurst, Houston, both of Tex. Primary Examiner c' l Husar [73] Assignee: Anderson, Greenwood & Co., Assistant Examiner-Leonard Smith Houston, Tex. Attorney, Agent, or Firm-Jack R. Springgate; Joe E. 22 Filed: Aug. 6, 1973 Edwards; Gay

[21] Appl. No: 385,885 [57] ABSTRACT R l t d US, Application Data A pump having a lost motion connection between the [63] Continuation of Ser. No. 132,353, April 8, 1971. power plston and F Pumpmg plston that the stroke of the pumping piston may be varied without 52 US. Cl 417/399, 91/313, 92/62, changing the Stroke of the Power piston, a restriction 92/65 in the outlet from at least one end of the power cylin- 51 Int. Cl. F04b /02 der to Control the rate of movement of the Power P [58] Field o{Search 417/398 399, 91/313; ton, and a control valve as a subcombination having 92/62, 65 129 relationships between the valve member and ports defined to prevent stopping of the pump in a mid posi- [56] References Cited tion. This abstract is neither intended to define the invention of the application which, of course, is mea- UNITED PATENTS sured by the claims, nor is it intended to be limiting as akmson 91/313 X to the scope of the invention in any way een 1,999,881 4/1935 Lowe 417/403 13 Claims, 7 Drawing Figures I36 I40 58 6 13a :42 I4 4 l 1 f 1 1 f 7 58 56 72 c o 55 A X 1 1;; 50 T v .:::t-2r "464 1.8 54 62 2 7o 2 i 1L\ A 1 w /fl 54 20 85 so so 76 84182 as sum 2 or s PATENTEnsEmmm PUMP This application is a continuation of US. Pat. application Ser. No. 132,353 filed Apr. 8, 1971.

The present invention relates to an improved pump.

An object of the present invention is to provide an improved pump having an adjustable stroke of its pumping piston which does not interfere with the stroke of the power piston.

Another object is to provide as a subcombination in a pump an improved control valve which avoids stalling and stopping of the pump.

A further object is to provide an improved liquid pump which is suitable for use in injecting chemicals into a line under pressure and can be operated with a gas at a pressure substantially below the injection pressure.

Another object is to provide an improved pump with a readily accessible adjustment of the stroke of the pumping piston.

Still another object is to provide an improved liquid pump which can be remotely controlled.

A still further object is to provide an improved pump capable of pumping-liquids to high pressure at varying rates which pump is of simple construction and requires minimum maintenance.

BRIEF DESCRIPTION OF THE DRAWINGS These and other objects and advantages of the present invention are hereinafter set forth and explained with reference to the drawings wherein:

FIG. 1 is a top view of the preferred form of improved pump of the present invention.

FIG. 2 is a schematic view of the pump and control valve illustrating their operation.

FIG. 3 is a sectional view of the improved pump of the present invention taken along its axis.

FIG. 4 is a partial view similar to FIG. 3 but showing the lost motion resulting from the stroke adjustment.

FIG. 5 is a detail sectional view of the improved control valve used on the improved pump of the present invention.

FIG. 6 is a partial sectional view of the control valve member to illustrate certain dimensions thereof.

FIG. 7 is a partial sectional view of the ported plate which coacts with the control valve member illustrating certain dimensions thereof.

DESCRIPTION OF THE PREFERRED EMBODIMENT As shown in the drawings the pump 10 includes the body 12 having a tubular cylinder 14 with a central bore 16 and

end blocks

18 and 20 held together by the bolts 22, the pumping cylinder 24 connected to end block 18, the cover 26 for the stroke adjusting means and the control valve 28. Suitable inlet and

discharge check valves

30 and 32 and a drain valve 34 are connected to the pumping cylinder 24. The bolts 22 also connect through the mounting bracket 36 which provides a mounting means for the pump 10. Suitable communication is provided through the

end blocks

18 and 20, the control valve block and plate (hereinafter described) and the tubing connections shown to deliver and exhaust power fluid to the opposite ends of the power chamber 38. Power fluid is supplied to control valve 28 through the connection 40 and is exhausted therefrom through the vent 42.

The power piston 44 is positioned within the power chamber 38 for reciprocation therein responsive to the supply and venting of power fluid to and from opposite sides of such chamber. The pumping piston or plunger 46 is positioned within the pumping chamber 48 in pumping cylinder 24 for reciprocation therein and is connected through the lost motion connection means, hereinafter described, to power piston 44. As shown, the pumping chamber 48 and the power chamber 38 are in axial alignment. The connecting rod 50 is secured to or is an extension of the plunger 46 and extends through the central portion of power piston 44 into threaded engagement with sleeve 52 as best seen from FIGS. 3 and 4, the flange 54 on connecting rod 50 forms an abutment or shoulder providing the driving connection for the discharge stroke of the plunger 46. The driving connection for the intake or suction stroke of plunger 46 is provided by the engagement of spring guide bushing 56 with sleeve 52. Sleeve 52 includes the annular projection 58 which is adapted to engage end block 20 to provide a stop on the suction stroke of plunger 46. The spring 60 surrounds connecting rod 50 and has one end engaging projection 58 and the other end engaging bushing 56 to urge piston 44 and sleeve 52 apart and thereby maintain piston 44 in engagement with flange 54 except during lost motion movement of piston 44 as shown in FIG. 4. The threaded connection between connecting rod 50 and sleeve 52 includes the lock nut 62. Such threaded connection which is readily accessible from the exterior of the pump 10 at any time by removal of cap provides the adjusting means for the lost motion connection between power piston 44 and pumping piston 46. This lost motion .connection determines the length of the stroke of pumping piston 46 without changing the length of stroke of the power piston 44.

The stroke adjustment is accomplished by removing the cap 26, releasing the lock nut 62 and rotating the connecting rod 50 with respect to the sleeve 52. In FIG. 3 which illustrates no lost motion in the connection, the connecting rod 50 is threaded as far through the sleeve 52 as possible thus positioning the inner end of sleeve 52 against the spring guide bushing 56 and the flange 54 against the power piston 44. When the relative positions of the connecting rod 50 and sleeve 52 are changed as shown in FIG. 4, Le, sleeve 52 is threaded outwardly on connecting rod 50, then power piston 44 is free to move during a portion of its stroke independent of pumping piston 46. On the suction portion of the stroke power piston 44 slides on connecting rod 50 and when bushing 56 and sleeve 52 contact pumping piston 46 is moved. On reversal, power piston 44 slides on connecting rod 50 until it engages flange 54 and thereafter pumping piston 46 is moved in its discharge stroke.

As shown in FIG. 3, the power piston 44 is provided with suitable seals for sealing both against the interior of chamber 38 and around the connecting rod 50. The seal around the plunger 46 is provided by the packing gland 64 which includes the packing sleeve 66, the packing 68 and the nut 70 which is threadedly engaged with end block 18 and engages annular shoulder 72 on pumping cylinder 24 to hold cylinder 24 and packing gland 64 in desired position. A drain connection 74 is provided through end block 18 for draining fluid from the packing 68.

The

pilot valves

76 and 78 are mounted in the

end blocks

18 and 20 respectively and each includes a stem projection 80 adapted to be engaged by the power piston 44 as it nears the end of its stroke to reverse the supply of power fluid. The

pilot valves

76 and 78 reverse the supply of power fluid by reversing control valve 28 which is a pressure responsive valve. Engagement of one of the stems 80 opens that pilot valve to provide communication between the

control valve connections

82, 83 and the

vent connection

84, 85 which provides a venting causing a reversal of control valve 28 as hereinafter explained.

The control valve 28 includes the block 86, and the plate 88 which are secured by cap screws 90 to end block 20 as best seen in FIG. 5. The block 86 has a central bore 92 with the piston 94 positioned therein and adapted to reciprocate axially thereof responsive to pressure differentials. The power fluid supply connection 40 connects into block 86 and is in communication with the annular chamber 96 around piston 94. Opposite connection 40 is a valving chamber 98 in which valve member 100 is adapted to slide with the movement of piston 94 and in valving engagement with plate 88. Valve member 100 includes the head 102, the hollow stem 104 and the seating ring 106. The stem 104 extends into the chamber 108 within piston 94 so that valve member 100 is biased toward seated engagement with plate 88 both by the fluid pressure within chamber 108 and by the spring 110.

Passageway 112 from the control valve connection 83 in block 20 and start button 114 are in communication with the central bore 92 of block 86 on one side of piston 94 and central valve connection 82 from block 18 is in communication with the central bore 92 on the other side of piston 94. Fluid from supply connection is conducted through port 116, into chamber 108 and through

restrictions

118 and 120 to the opposite sides of pistons 94. Thus, whenever one side of piston 94 is vented, piston 94 moves responsive to the pressure differential created and as hereinafter explained changes the direction of power piston 44. When piston 94 completes its movement, i.e., is stopped by engagement with one of the shoulders 122 and 124, the fluid pressure across the piston 94 is equalized slowly by flow through the

restrictions

118 and 120.

Start button 114 is used to position valve 94 against shoulder 122 by venting the fluid from that side of piston 94 to create a pressure differential moving piston 94 to the left as seen in FIG. 5.

The plate 88 is secured between block 86 and block 20 and is retained in fixed position with at least two locating pins 126 which are set in block 20 and extend through plate 88 into block 86. Suitable sealing means are provided between block 20 and plate 88and between block 86 and plate 88 such as gasket 128 and the O-rings shown.

Plate 88 defines the

ports

130, 132 and 134 which are in communication with the passageway 136 communicating to passageway 138 in block 18, the vent passageway 140 connecting to vent 42, and the passageway 142 in block 20 respectively.

As best seen in FIGS. 2 and when piston 94 is against shoulder 122 by venting of pressure through the valve 78 fluid is delivered from supply connection through port 134 and passageway 142 to deliver fluid to the block 20 side of power chamber 38 and pressure fluid from the other side of piston 44 is vented through passageway 136, port 130, port 132 and vent passageway 140. When piston 44 has completed its stroke toward block 18 it opens valve 76, venting the right side of bore 92 to cause piston 94 to move against shoulder 124. In this position pressure fluid is supplied through port 130,

passageways

136 and 138 to the block 18 side of power chamber 38 and the block 20 side of chamber 38 is vented through passageway 142,

ports

134, 132 and vent 42.

The rate at which power piston reciprocates may be controlled by restricting the flow venting from the power chamber 38 to thereby decrease the speed of movement of power piston 44. This restriction may be of the flow from vent 42 by partially closing valve 144. If a variation in the stroke speed is desired between suction and discharge, the valve 146 in line 148 which connects between passageway 136 and passageway 138 is adjusted to restrict the venting flow therethrough to provide a slow pumping or discharge stroke and a fast suction stroke. To accomplish this, valve 146 is a combination needle valve and check valve. Adjusting the needle to a more restricted position restricts the return flow therethrough while allowing full flow in the other direction.

The specific dimensional relationships of the valve member and the

ports

130, 132 and 134 in plate are shown in FIGS. 6 and 7. Those relationships are as follows: The width C of the seating surface of valve member 100 is equal to or greater than the diameters d of the

ports

130, 132 and 134 in plate 88 to fully cover and close the ports to avoid bleeding between the ports. The inside diameter A of valve member 100 is equal to or smaller than the space E between the edges of the outermost ports and 134. This assures that both of the

ports

130 and 134 are not vented at the same time. Also the outside diameter B of valve member seating ring 106 is equal to or greater than the overall distance F across the

ports

130, 132 and 134. This avoids directing pressure fluid to both

ports

130 and 134 and thus to both sides of the piston 44.

One actual control valve structure provides port spacing of 0.250 inches with ports being 0.l28 inches in diameter (d). The overall space F is 0.628 inches and the space E is 0.372 inches. On the valve member 100 the outside diameter B is 0.680 inches, the inside diameter A is 0.370 inches and the width of the seating surface C is 0.155 inches.

From the foregoing it can be seen that the improved pump of the present invention includes adjustments of the pumping rate by adjusting the length of the pumping stroke without changing the length of stroke of the power piston and by restricting the vent from the pumping chamber either from both sides or only from the discharge C side of the power piston to slow the discharge stroke. Also an improved pressure responsive control valve for the pump which is operable responsive to pressure venting provides controlled operation of the pump with assurance that the pump will not stall or stop because of faulty valving.

What is claimed is:

1. A pump, comprising a body having a central bore and end blocks defining a power chamber,

a power piston positioned for reciprocation in said power chamber,

a pumping cylinder connected to one of said end blocks and defining a pumping chamber therein,

a pumping piston positioned for reciprocation in said pumping chamber,

means for supplying a power fluid alternately to the opposite ends of said power chamber to reciprocate said power piston therein,

means for connecting said pumping piston to said power piston to reciprocate said pumping piston within said pumping chamber,

means for adjusting said connecting means to vary the length of stroke of said pumping piston with respect to said power piston, said adjusting means being readily accessible to the exterior of said pump body, and

means coacting with said connection means for maintaining a preselected length of stroke of said pumping piston and for preventing movement of the pumping piston on its suction stroke responsive to suction pressure.

2. A pump, comprising a body having a central bore and end blocks defining a power chamber,

a power piston positioned for reciprocation in said power chamber,

a pumping piston positioned for reciprocation in said pumping chamber,

means coacting with said connecting means for maintaining a preselected length of stroke of said pumping piston and for preventing movement of the pumping piston on its suction stroke responsive to suction pressure, said connecting means including a rod connected to said pumping piston and extending through said power piston, and

a sleeve connected to the end of the rod,

said rod having an abutment adapted to be engaged by said power piston to drive said pumping piston in one direction,

said sleeve having an abutment adapted to be engaged by said power piston to drive said pumping piston in the other direction,

said stroke maintaining means includes an abutment on said sleeve adapted to be engaged by the other of said end blocks, whereby the travel of said sleeve and said pumping piston are limited on the suction stroke.

3. A pump according to claim 2, wherein said rod and said sleeve extend through said other of said end blocks to be exposed on the exterior of said pump for adjustment.

LII

4. A pump according to claim 2, wherein said connection of said sleeve to said rod is a threaded connection, and including a lock nut threadedly engaged on said rod and adapted to engage said sleeve to releasably lock said sleeve in its position on said rod.

5. A pump according to claim 2, including means for resiliently urging said power piston toward engagement with said abutment on said rod.

6. A pump according to claim 2, including a lock nut threadedly engaged on said rod and adapted to engage said sleeve to releasably lock said sleeve in its position on said rod.

7. A pump according to claim 2 including means for variably restricting the flow of power fluid flowing from at least one end of said power chamber to control the speed of movement of said power piston.

8. A pump according to claim 2 wherein said supply means includes a control valve having a body with a central bore,

a valve piston positioned for reciprocation in said central bore,

means communicating with said bore on opposite sides of said valve piston for venting said bore to move said piston,

a valving chamber in said body,

means communicating with a valving chamber to supply fluid thereto,

restricted passageways communicating from said valving chamber to opposite sides of said valve piston,

three ports defined in said body and in communication with said valving chamber,

a valve member connected to said valve piston for reciprocation therewith and adapted to coact with said ports to direct supply fluid to one of said ports from said valving chamber and to provide communication between the other two of said ports.

9. A pump according to claim 8, including means for biasing said valve member into sealing engagement with the surface of said valving chamber in which said ports are defined.

10. A pump according to claim 9, wherein said biasing means includes a spring engaging said valve member and said piston to urge said valve member into said sealing engagement.

11. A pump according to claim 9, wherein said biasing means includes a central chamber defined within said piston,

said valve member extending into and being slidable in said central chamber, and

means communicating from said valving chamber to said central chamber to expose said valve member to the pressure of said power fluid.

12. A pump according to claim 8, wherein said three ports are spaced apart with their centerlines lying in a plane parallel to the axis of said valve piston, and

said valve member includes an annular seating surface,

the width of said annular seating surface being at least as great as the diameter of said ports,

the inside diameter of said annular seating surface being not more than the distance between the inner edges of the two outer ports,

7 8 the outside diameter of said annular seating surface manually operated means for venting connected into being at least equal to the distance between the said central bore to position said valve member in outer edges of the two outer ports. one of its positions. 13. A pump according to claim 8, including

Claims

1. A pump, comprising a body having a central bore and end blocks defining a power chamber, a power piston positioned for reciprocation in said power chamber, a pumping cylinder connected to one of said end blocks and defining a pumping chamber therein, a pumping piston positioned for reciprocation in said pumping chamber, means for supplying a power fluid alternately to the opposite ends of said power chamber to reciprocate said power piston therein, means for connecting said pumping piston to said power piston to reciprocate said pumping piston within said pumping chamber, means for adjusting said connecting means to vary the length of stroke of said pumping piston with respect to said power piston, said adjusting means being readily accessible to the exterior of said pump body, and means coacting with said connection means for maintaining a preselected length of stroke of said pumping piston and for preventing movement of the pumping piston on its suction stroke responsive to suction pressure.

2. A pump, comprising a body having a central bore and end blocks defining a power chamber, a power piston positioned for reciprocation in said power chamber, a pumping cylinder connected to one of said end blocks and defining a pumping chamber therein, a pumping piston positioned for reciprocation in said pumping chamber, means for supplying a power fluid alternately to the opposite ends of said power chamber to reciprocate said power piston therein, means for connecting said pumping piston to said power piston to reciprocate said pumping piston within said pumping chamber, means for adjusting said connecting means to vary the lEngth of stroke of said pumping piston with respect to said power piston, said adjusting means being readily accessible to the exterior of said pump body, and means coacting with said connecting means for maintaining a preselected length of stroke of said pumping piston and for preventing movement of the pumping piston on its suction stroke responsive to suction pressure, said connecting means including a rod connected to said pumping piston and extending through said power piston, and a sleeve connected to the end of the rod, said rod having an abutment adapted to be engaged by said power piston to drive said pumping piston in one direction, said sleeve having an abutment adapted to be engaged by said power piston to drive said pumping piston in the other direction, said stroke maintaining means includes an abutment on said sleeve adapted to be engaged by the other of said end blocks, whereby the travel of said sleeve and said pumping piston are limited on the suction stroke.

8. A pump according to claim 2 wherein said supply means includes a control valve having a body with a central bore, a valve piston positioned for reciprocation in said central bore, means communicating with said bore on opposite sides of said valve piston for venting said bore to move said piston, a valving chamber in said body, means communicating with a valving chamber to supply fluid thereto, restricted passageways communicating from said valving chamber to opposite sides of said valve piston, three ports defined in said body and in communication with said valving chamber, a valve member connected to said valve piston for reciprocation therewith and adapted to coact with said ports to direct supply fluid to one of said ports from said valving chamber and to provide communication between the other two of said ports.

11. A pump according to claim 9, wherein said biasing means includes a central chamber defined within said piston, said valve member extending into and being slidable in said central chamber, and means communicating from said valving chamber to said central chamber to expose said valve member to the pressure of said power fluid.

12. A pump according to claim 8, wherein said three ports are spaced apart with their centerlines lying in a plane parallel to the axis of said valve piston, and said valve member includes an annular seating surface, the width of said annular seating surface being at least as great as the diameter of said ports, the inside diameter of said annular seating surface being not more than the distance between the inner edges of the two outer ports, the outside diameter of said annular seating surface being at least equal to the distance between the outer edges of the two outer ports.

13. A pump according to claim 8, including manually operated means for venting connected into said central bore to position said valve member in one of its positions.