US3058307A

US3058307A - Hydraulic pneumatic well pumping apparatus

Info

Publication number: US3058307A
Application number: US52737A
Authority: US
Inventors: Samuel V Smith
Original assignee: PNEU HY CO
Current assignee: PNEU HY CO; PNEU-HY Co
Priority date: 1960-08-29
Filing date: 1960-08-29
Publication date: 1962-10-16
Anticipated expiration: 1979-10-16

Description

Oct. 16, 1962 s. v. SMITH 3,0

HYDRAULIC PNEUMATIC WELL PUMPING APPARATUS Filed Aug. 29, 1960 5 Sheets-Sheet 1 INVENTOR QMUEL 'W'SM/TH 4 JQQQQQAZ M ATTORNEY Oct. 16, 1962 s. v. SMITH 3,058,307

HYDRAULIC PNEUMATIC WELL PUMPING APPARATUS Filed Aug. 29, 1960' 5 Sheets-Sheet 2 INVENTOR SnML/EL \ZSM/TH ATTORNEY Oct. 16, 1962 s. v. SMITH HYDRAULIC PNEUMATIC WELL PUMPING APPARATUS Filed Aug. 29, 1960 5 Shee ts-Sheet 4 PRESSURIZED RESERVOIR INVENTOR. SQMUEL VSM/ TH ATTORNEY Oct. 16, 1962 s. v. SMITH HYDRAULIC PNEUMATIC WELL PUMPING APPARATUS Filed Aug. 29, 1960 5 Sheets-Sheet 5 7 a ll 2' M 6 6 2 2 m *4 2 2 5 5 Ms 7 \l\ 2 II. P 7 o 2 a .4 w 2 M M 2 {O2 8 25 Mum 4 3 2 2 27 V 3 w 2 Q 6 x M v 3 2 INVENTOR. SQMUEL TITS/WITH ATTO R N-EY ire This invention relates to apparatus used for pumping wells and more particularly to improvements in fluid pressure powered pump jack-s operable to raise and lower well pumps and the like.

This application is a continuation-in-part of copending application Serial No. 678,807, filed August 19, 1957 by Samuel V. Smith for Pneumatic Hydraulic Pumping Apparatus which issued as United States Letters Patent No. 2,947,144 on August 2, 1960, and application Serial No. 792,354, filed February 10, 1959 by Samuel V. Smith for Reversible Discharge Flow Variable Displacement Pump.

In general, fluid pressurized pump jacking units presently in use are characterized in construction as extending to a considerable height above the ground over the well, it being conventional practice to mount a large pumping assembly vertically over the pump rod for supporting the latter and for reciprocating it in the well. However, at the present time there is increasing public and civic expression of a need for restricting the observable size of such equipment, particularly in residential areas where the benefits of petroleum production are recognized and sought at the expense of accommodating to the necessary presence of the production machinery. In addition, there has also been an increasing awareness of the attractive danger of conventional well pumping units to children, such as encountered in the large pivoting booms of conventional pumping units. In copending application Serial No. 678,807 supra, there is disclosed and claimed an improved fluid pressure powered pump jack unit which minimizes the apparent size thereof to the observer While at the same time increasing the reliability and improving the operation of the equipment. The invention disclosed and claimed therein contemplates the provision of apparatus for vertically reciprocating a Well pump rod or the like projecting above ground surface level, comprising a plurality of vertical cylinders spaced apart latenally so that they may be sunk downwardly into the ground in a laterally offset relation to the well, together with pistons reciprocal up and down in the cylinders and means for supporting the pump rod at its projection above ground by the pistons and for reciprocating the supported rod up and down in response to piston reciprocation. The pistons are then reciprocal below ground surface level by application of fluid pressure so that a large part of the equipment needed to lift and lower the pump rod is underground and out of sight of the observerv In accordance with the apparatus described and claimed in the above entitled application Serial No. 678,807, the pistons and cylinders are preferably laterally spaced on opposite sides of the center corresponding to the Well location, so that an above-ground cross-head structure interconnecting the piston rods may bridge over the well pump rod for reciprocating the latter as the pistons are displaced up and down in the cylinders. Such displacement is eflected by means of interruptedly communicating hydraulic pressure, for example, to a first pair of jacking pistons on opposite sides of the well and tending interruptedly to raise the pump rod, and also by means constantly communicating gas pressure to a second pair of balanced pistons likewise spaced on opposite sides of the Well and underground tending constantly to naise the pump rods. While the pressure communicated to the balance rods is insuflicient alone to raise the pump rod,

3,058,37 Patented Oct. 16, 1962 the latter is lifted only during communication of hydraulic pressure to the jacking pistons, interruption of such communication allowing the pistons to drop on the pump rod downstroke, the rate of drop being controlled by restricting the back flow of hydraulic fluid pushed from the cylinders by the pistons through a pump and valve arrangement.

As an element of the apparatus of the present invention, a variable displacement reversible discharge fluid pump is utilized. This pump is of the type wherein the rate of fluid discharged can be controlled and the direction of flow of fluid from the pump can be reversed, with either or both of these controls being possible while the pump is ope-hating. Although other pumps of this type can be utilized, the pump used in the presently preferred embodiment of the apparatus of the present invention is of an improved type related to that disclosed and claimed in copending application Serial No. 792,354 supra, and thus forms a continu-ation-in-part of that application.

In application Serial No. 792,354 a pump is shown and described which is capable of supplying fluid at any desired rate of flow within a predetermined range by an adjustment that can be made to the pump while it is operating. The pump permits reversal of the direction of fluid flow during the operation thereof by the same means employed in controlling the rate of fluid discharged therefrom. Variation in the rate of fluid discharged from the pump and reversal of the direction of flow of discharged fluid is attained by moving a portion of the elements comprising the pump combination, which eliminates the necessity of resorting to intricate piping and valving.

It is an object of the present invention to provide an improved pump of the type described above and more particularly an improved pump capable of supplying fluid at any desired rate of flow Within a predetermined range by a simple adjustment which can be made to the pump while it is operating.

It is another object of the present invention to provide such a pump which is of simplified structure and requires a minimum of maintenance attention.

Another object of the present invention is to provide an improved variable flow reversible pump that is particularly adapted to supply fluid at a desired pressure and at a desired rate and direction of flow which varies through a sequence of steps, with the adjustment of the pump to provide this sequence of steps wherein the rate of flow and direction of flow is altered, being attained by either mechanical, hydraulic, electrical or manual means.

Yet another object of the present invention is to provide a well unit pumping system utilizing a pump in accordance with the present invention which obviates the necessity for balance cylinders and pistons as discussed above.

It is a further object of the present invention to provide an improved and simplified hydraulic-pneumatic pumping unit which includes a completely closed hydraulic circuit which is independent of fluid in the well.

Yet another object of the present invention is to provide a pumping unit of the type described wherein the polish rod load is balanced by a closed hydraulic system.

it is another object of the present invention to provide a fluid power hydraulic-pneumatic pumping unit which has a low fluid loss in a closed hydraulic system such that no scavenger system is required.

It is a still further object of the present invention to provide such a fluid power pumping unit sytem which provides adjustment for the length and placement of the stroke of the polish rod.

Yet another object of the present invention is to provide such a fluid power pumping unit system which provides 7 a positive shifting action between the up and down strokes of the polish rod within the well with a very soft reversal action.

It is a principal object of the present invention to provide a fluid power pumping unit that is designed to utilize hydraulic rams which raise and lower the polish rod within the well, which rams may be mounted below ground level to reduce the overall height of the visible portion of the well pumping unit and to provide quick accessibility to the well for servicing jobs, which unit includes an improved pump of the variable discharge, reversible flow type.

The present invention is a balanced pneumatic-hydraulic pumping unit adapted to be affixed to a pump or polish rod extended above the well head for pumping well fluid from the well within which the pump rod is reciprocal and comprises the fluid cylinder positioned proximate the well and extending substantially parallel thereto from a position above the well head to a position substantially below the well head. A longitudinally movable piston is positioned within the fluid cylinder and is movable therein by introduction of fluid under pressure into the cylinder whereby the fluid pressure exerts an upward force on the piston. The piston is connected to the pump rod such that the pump rod is moved upwardly with the piston. A fluid reservoir is provided together with means for maintaining air under pressure in the reservoir above the fluid contained therein. The pressure of the air is variable to provide a pressure balance system. A pump as described above is connected to' the reservoir and the fluid cylinder, the pump being of the type which can be reversed as to its direction of flow during the operation thereof. A second hydraulic pump is operatively connected with the reversible pump to furnish a source of fluid under pressure for reversing the reversible pump at the appropriate point of the pumping cycle and suitable valving arrangements are provided for achieving the reversal of the reversible pump. Fluid lines are connected between the reversible pump and the fluid cylinder and between the reversible pump and the reservoir such that fluid under pressure is pumped to the fluid cylinder by the pump and returned from the fluid cylinder to the reservoir. An air compressor is operatively connected to the reservoir together with automatic means for actuating the compressor when the pressure within the reservoir falls below a predetermined desired level.

The novel features which are believed to be characteristic of the present invention both as to its organization and method of operation, together with further objects and advantages thereof, will be better understood from the following description considered in connection with the accompanying drawings in which a presently preferred embodiment of the invention is illustrated by way of example. It is to be expressly understood, however, that the drawings are for the purpose of illustration and description only and are not intended as a definition of the limits of the invention.

the various components of the pump of the present invention;

FIGURE 5 is a plan view partially schematic of the hydraulic-pneumatic pumping unit of the present invention;

FIGURE 6 is a partially diagrammatic view in elevation corresponding to FIGURE 5;

FIGURE 7 is an enlarged view of the pump of the present invention as connected to the reservoir of the pumping unit;

FIGURE 8 is an enlarged partial view partly in section showing the reversing mechanism in accordance with the present invention for reversing the direction of flow through the fluid pump and the direction of movement of the polish rod;

FIGURE 9 is a plan view corresponding to FIGURE 8;

FIGURE 10 is a view in elevation taken along line 10-10 of FIGURE 8; and

FIGURE 11 is a detailed view partly in section of the clutching mechanism for connecting the motor drive of the pumping unit with the compressor thereof.

The present invention utilizes many of the principles of operation and construction set out in the copending applications Serial Nos. 792,354- and 678,807 supra, but is an improved and simplified apparatus for pumping fluid from a well. Although the invention described and claimed in the copending applications is eminently satisfactory, the present invention has certain advantages and improvements thereover including the increased simplicity in both construction and operation, as more particularly pointed out hereinafter.

Referring now to FIGURES 1 through 4, the presently preferred embodiment of the improved variable flow reversible pump of the present invention is shown. The general arrangement of the pump designated by the numeral 99 includes a driven shaft A having a cylindrical rotor B fixedly mounted thereon. Rotor B has a number of circumferentially spaced radially extending slots C formed therein, and a fiat rectangular blade D slidably mounted in each of the slots. A ring E is provided which is of substantially the same width of that of the blade D but is substantially larger in diameter than rotor B, as may be seen in FIGURES 2 and 4.

The slide block, generally identified by the letter F, includes a circular member G which has two diametrically opposed pistons H projecting therefrom. Intermediately located between pistons H and projecting from member G are two guide blocks I that have parallel faces.

A pump housing L is provided with a main housing portion L-1 and a cover L2, as shown particularly in FIGURES l and 3. The housing L-l and cover L2 are of such structure that together with slide block F, circular member G, pistons H, flanges K and sealing means to be described hereinafter may cooperatively define two separate compartments M and N of substantially the same shape that are situated within the housing L. The housing L1 defines diametrically opposed openings 20 and 2.1 therethrough, which openings are adapted to receive the pistons H and serve as cylinders within which the pistons are movable. Referring particularly to FIGURES 2 and 3, the pistons H are removably mounted upon the slide block F in order to allow assembly of the pump. Thus, the slide block F has diametrically opposed cylindrical protrusions 23 which are mateable with cylindrical indentations 24 in the forward face of the pistons H. In order to position the slide block F within the housing L1 the slide block including the rotor B is placed within the housing and the pistons H are inserted through the

openings

20 and 21 until the indentation 24 is mated with the protrusion 23. A retaining rod having a threaded end portion 25 mateable with a female threaded opening in the slide block is utilized to retain the piston in the assembled position. A shoulder 26 is provided on the rod 27 which shoulder is spaced from the threaded end portion by an amount proper to abut the forward face 30 of the piston in the assembled position. Thus, after the slide block F is positioned within the housing, the pistons are assembled thereon by inserting the pistons H through the

openings

20 and 21 and threading the retaining rod 27 into engagement with the slide block through the opening 31 of the piston until the shoulder 26 abuts the forward face 30 of the piston. V

The flange K-1 is then positioned over the rod 27 and is such that the opening through the flange K-l allows sliding movement of the rod Within the piston. The flanges K-l and K-2 are afixed to the housing L by retaining means such as bolts 32 A first fluid conduit is threadably engaged with the housing L-l through the wall 0 thereof to provide a fluid opening 40 through the wall of the main housing section L1 to the space or compartment M previously described, and described in greater detail hereinafter. Similarly, a second fluid conduit P is threadably engaged with an opening P through the wall of the main housing section L-l such that the conduit P provides a fluid opening 41 in communication with the fluid compartment N within the housing L. The fluid conduit and

fluid passages

40 and 41 are circumferentially spaced about the housing at a spacing which will become more apparent hereinafter.

When the rotor B is rotated in a counterclockwise direction with reference to FIGURE 2, and fluid is admitted through the conduit P into the compartment N and the slide block F has been moved the maximum distance toward the cylinder 21, fluid in the compartment N enters the spaces S defined between the blades D and the interior surface of the ring E to be positively dis placed from the compartment N into the compartment M. As this fluid displacement continues from the second to the first compartment N and M respectively, the fluid pressure in compartment M builds up to cause discharge of the fluid from the first fluid conduit 0. By moving the slide block F away from the cylinder 21, the space in each of the spaces S is decreased and the rate at which fluid is discharged from compartment N to compartment M is decreased, assuming of course that the rate of rotation of the shaft and rotor remain constant. When the slide block F is moved a maximum distance away from the cylinder 21 and toward the cylinder 2%, the space adjacent the cylinder 20 is completely eliminated and the spaces S adjacent the first cylinder 2% become maximum. Since the rotation of the rotor remains the same the fluid is then withdrawn from the first compartment M to be positively carried from spaces S into the second compartment N. The pressure on the fluid in the first compartment increases and causes fluid to discharge through the fluid conduit 0. Thus, it can be seen that the conduits O and P will interchangeably serve as fluid inlets and outlets from the compartments M and N respectively. Also, by varying the position of the slide block F, the rate of discharge from either conduit 0 or P can be controlled.

Thus, referring now in detail to FIGURES 1 through 4, the shaft A is connected to any conventional source of power. The shaft comprises a longitudinally extending section 50 of enlarged transverse cross-section that is positioned within the confines of the housing L as shown particularly in FIGURE 3. The rotor B is fixedly mounted on the shaft section 50 by suitable means. The rotor B is centrally positioned on the shaft section 50 and the projecting portions of the section 50 are rotatably supported by a pair of roller bearing assemblies 51 affixed to the housing L at the outer surfaces thereof. The roller bearing assemblies include a flange 52. which is bolted to the housing and defines a space within which a sealing means 53 and the roller bearing 54 are positioned in sealing rotating contact with the shaft A.

As previously described, the housing L is made up of a main housing section L-li and a cover section L-Z. The main housing section L4 is generally cylindrical in cross-section with an upstanding side wall 60 and a bottom surface 61. The bottom surface 61 is closed except for the opening 62 therethrough which is adapted to receive the shaft A and the bearing and sealing means as previously described. Through the wall 60 there are provided the diametrically

opposed openings

20 and 21 which serve as cylinders for the pistons H. Thus, the

openings

20 and 21 are substantially equal in di- 8 ameter and are positioned approximately mid-way of th height of the wall 60. Also provided through the wall 60 are the fluid openings 0 and P with which the fluid conduits O and P are threadably mateable. The openings O and P are at opposite sides of the cylinder 21 and are in communication with the spaces M and N. Upon the inner surface of the bottom wall of the housing section L-l there is provided a raised bearing surface 65 which extends across a diameter of the interior of the housing section L-l. The bearing section 65 extends symmetrically along the same diameter as the cylinders 2t and 21 and is of such width that it forms a bearing contact for the block F. The slide block F and rotor B are sliding bearing contact with the bearing surface 65 such that the bearing surface 65 divides the interior of the housing L-l into two sections on opposite sides of the housing. These sections correspond to the spaces M and N.

The interior of the upstanding wall 60 is also generally cylindrical in configuration. There is provided, however, at opposite sides of the housing L-l first and second bearing surfaces 66 and 67 respectively. These

surfaces

66 and 67 are planar surfaces which are perpendicular to the bottom wall 61 of the housing and are parallel to the diameter extending through the cylinders 22% and 221. These bearing surfaces 66 and 67 act as hearing guide surfaces to retain the slide block in alignment within the housing as it is moved from the first to the second position, as described more fully hereinafter.

The cover L-Z is again generally circular in configuration and is mateable with the main housing section L-1. The cover L-2 is generally plate-like but includes an opening 70 through which the shaft passes and in which the bearing and sealing means are positioned by means of the bearing and sealing assembly 51 as previously described. The cover L-2 has a depending circular flange substantially equal in diameter to the inside diameter of the wall 60 of the housing section L-1 such that it is mateable therewith. In this connection it should be noted that the bearing surfaces 66 and 67 extend upwardly from the inner surface of the bottom wall 61 of the housing to a height which is less than the total height of the upstanding wall and that indentations are provided from the circular side wall proximate the fluid openings 0' and P. Thus, the circular flange on the cover section L2 will mate with the interior surface of the housing and will extend downward from the upper surface of the housing section L-1 to a height at which it is spaced above the slide block bearing surface 65 by a distance equal to the height of the rotor and blade assembly such that the rotor is positioned in bearing contact with the cover section L-Z and the bearing surface 65. Accordingly, with the cover L-2 in mated assembly with the main housing section L-l the compartment M extends both above and below the slide block F in the proximity of the fluid opening 40 from the housing, while the compartment N also extends above and below the slide block F in the proximity of the fluid path 41 through the housing. A space beneath the slide block, rotor and blades is then provided from the fluid opening 4-1 beneath a portion of the slide block and rotor to the position proximate the cylinder 20, since the bearing surface 65 is above the interior surface of the bottom wall 61. Similarly the compartment M also extends beneath the rotor to the position proximate the cylinder 29 and beneath the rotor and block.

The slide block F, as shown in FIGURES 2. and 4, has two guide blocks I extending outwardly from the generally circular configuration of the slide block F defined by the diameter 76. The guide blocks J are diametrically opposed and intermediately positioned between the two pistons H. The guide blocks terminate in flat parallel bearing faces 77 which faces are parallel to the axis through the pistons H. The axis through the pistons H-l. and H4 is coincident with the axis through the-

cylinders

20 and 21 when the pump is in the assembled condition. The bearing guide faces 77 are at a distance from the center line of the slide block, which distance is equal to the distance of the bearing surfaces 66 and 67 from the axis through the

cylinders

20 and 21. Thus, when the pistons H are positioned within the

cylinders

20 and 21 the bearing faces 77 of the guide blocks J are in bearing contact with the hearing'

surfaces

66 and 67 and the slide block is constrained to move in a straight line path along the diameter through the apparatus, which is the axis of the pistons H and

cylinders

20 and 21.

As shown particularly in FIGURES 2 and 3, the flanges K-l and K-Z which position the actuating rods 27 of the pump define an opening therethrough which is slidably mateable with the exterior surface of the actuating rods 27. Sealing means 78 are provided to effect a fluid seal between the rod 27 and the flanges K-fi and K2 respectively. Thus, the flanges 31-1 and l i-2 act to close the end of the cylinders 2i and 21 respectively. Suitable means for effecting the seal, such as the sealing means 79 and the protrusion 80, which extends a slight distance into the cylinders is provided. Thus, the flange K-l closes the cylinder 20 while the flange K42 closes the cylinder 21. The pistons H-1 and H-2 respectively are, however, movable within the cylinders and the for- .ward face 34M and 39b of each of the pistons is spaced from the inner face 31 of the flange when the slide block I is in a central position at which its axis corresponds to the central axis of the housing L. That is, the pistons 1-1-1 and H2 are of such length that they allow the movement of the slide block I from the first position at which the fluid opening 40 acts as a fluid inlet, to the second position at which the fluid path 41 acts as an inlet. Through each of the flanges K-I and K-2 there is provided an opening 90 into which a threaded connection can be made for communication of a fluid-carrying line with the

cylinders

20 and 21 respectively. Thus, by introducing fluid under pressure through the opening 9%) in each of the flanges, pressure can be exerted upon the face of the piston 3th to cause the piston to be moved inwardly in the

cylinder

20 or 21, depending upon the application of fluid pressure within the cylinders. The relative movement of the various components of the apparatus will become more apparent hereinafter in connection with the description of the apparatus.

An upper annular groove 93 is provided in the bearing face of the cover section L2 and a lower annular groove 94 is provided in the bearing section 65 of the housing L-l to equalize the pressure at the rearward side of the blades D in the rotor B. That is, a fluid path 95 is provided extending from the fluid chamber N to the annular groove 94 and a fluid passage as is provided from the chamber M to the upper annular groove 93. The annular grooves 93 and 94 are at a radius with respect to the rotor B that is greater than the minimum radius of the slots C such that the slots C toward their inner end are in communication with the grooves $3 and 94. Thus, the pressure in the chamber N can be communicated to the rearward end of the blades D to keep the blades retained in a radially extended position when the pressure at the exterior end thereof becomes too great to allow their free movement due to centrifugal force. That is, the pressures against the blades are equalized in order to allow their free movement. In order to avoid loss of pressure within the chambers N or M when one is higher than the other, a ball check valve is inserted in each of the

fluid passages

95 and 96 to retain the high pressure at the inner end of the blade when the pressure within either the chambers M or N decreases below that value.

Thus, in operation the improved pump of the present invention is utilized to exhaust fluid through the first fluid conduit with the second fluid conduit P acting as an inlet, or to exhaust fluid from the pump through the second fluid conduit P with the first conduit 0 acting as the inlet. The shaft A is connected to a source of rotating power of the necessary magnitude to provide fluid at the desired pressure when discharged from either the first conduit 0 or the second conduit P. The source of rotational power for the shaft A should preferably rotate the shaft in rotor B in a counterclockwise direction when the invention is positioned as shown in FIGURE 2.

With the rotor rotating in the counterclockwise direction when the fluid is to be discharged from the pump through the first fluid conduit 0 the slide block and ring member will assume the position shown in FIGURE 2. That is, fluid under pressure is admitted to the cylinder 2% through the fluid conduit 90 in the flange K-l to force the piston 1-1-1 toward the shaft A by the action of the fluid under pressure upon the face 30 of the piston H-l. Movement of the piston 1-1-1 in the direction to the right in FIGURES 2 and 3 causes the ring-shaped member and the guide block F to be moved toward the cylinder 21 to assume the position as shown in FIGURES 2 and 3 where the interior surface of the ring E is eccentrically located relative to the circumferential exterior surface of the rotor B to the right of the rotor. When the pump is first used and the shaft A rotated the blades are initially moved out by centrifugal force, but as fluid pressure builds up in the second compartment N, fluid enters the bore 95 in communication therewith to compress the check valve and displace the valve from the seat. Thereafter this fluid under pressure flows through the groove 94 into the slot C to force the blades D radially outward. Due to the eccentric positioning of the rotor B relative to the ring E the hydraulic force thereon moves the blade ,radially outward as each blade approaches the second fluid opening 41. When the blades D are thus outwardly disposed, together with the exterior circumferential surface of the rotor B and the interior surface of the ring E, they cooperatively define arcuate pockets or spaces S that move the fluid being pumped toward the first fluid opening 4%.

As the rotor B rotates in a counterclockwise direction, fluid is carried into space S from the second compartment N to the first compartment M by positive displacement. As a result of the continuous discharge of fluid thereinto, pressure builds up in compartment M to cause fluid in this compartment to discharge therefrom through the first fluid opening 40. It will be apparent that the rate of discharge from the conduit 0 is dependent not only on the volume of each of the spaces S but the rate at which the rotor B is rotated to sequentially move each space S from the compartment N to the compartment M.

By varying the degree of eccentricity of the slide block relative to the rotor B, it is not only possible to control the magnitude of the volume of spaces S, and thus control the'rate of discharge from either conduit 0 or P, but also to regulate the direction of fluid flow through the pump. It can be seen that when the slide block F is so disposed as shown in the drawing relative to rotor .B, the volume of spaces S adjacent the second cylinder 21 is greater than that of spaces adjacent the cylinder 20, whereby fluid will be carried from the compartment N to the compartment M and discharged from the compartment M. Thus the fluid pressure in the compartment M tends to increase and fluid will be forced to flow from the opening an in the fluid conduit 0. From the foregoing it can be seen that by moving the slide block F toward the cylinder 26, Le, to the left in FIGURE 3, the rate of fluid discharge from the compartment M is not only reduced, but after the volume of the spaces S adjacent the first cylinder 24} becomes greater than that of the spaces adjacent the second cylinder 21, the fluid will he carried from the first fluid port 40 and compartment M in a counterclockwise direction around past the cylinder 20 and into the compartment N where it is discharged from the pump through the fluid opening 41 *and 'the conduit P. Accordingly, direction of flow through the pump is from the conduit as an inlet through the pump and from the pump through the conduit P as an outlet.

In the present invention the source of fluid pressure for exerting the moving force upon the pistons H-1 and H-2 to govern the direction of flow through the pump is obtained by means of a secondary fluid pump 1131) which is attached to the driven shaft A exteriorly of the pump housing L as shown in FIGURE 7. The operation of the secondary pump for supplying fluid pressure as a reversing force for the main pump will become more apparent in connection with the cycle of operation as described hereinafter in connection with the description of the well pumping apparatus of the present invention.

Referring now to FiGURES 5 through 10, a presently preferred embodiment of the well pumping apparatus of the present invention is shown. The pump 9% previously described is mounted upon a reservoir 101 which contains suitable hydraulic fluid for operation of the apparatus. A pair of operating cylinders 1152 and 1113 are extended vertically and are laterally spaced on opposite sides of an underground well casing 131) within which a polish rod or pump rod 131 is reciprocated to extract fluid from the well above the well head 132 as shown particularly in FTGURE 6. The operating

cylinders

102 and 1 33 extend from a position above the well head downward to an underground location within casings 134, which serve to locate and position the operating cylinders with respect to the well casing and provide accessibility to the cylinders and removal of the cylinders from the underground location. The lower end of the cylinders are closed by suitable means such as steel plugs to maintain a fluid-tight condition, and the cylinders are supported by means such as concrete pads 135 to support the vertical load and forces imposed on the cylinders. The upper ends of the cylinders are aflixed to cylinder heads 136 by means of which the fluid connections to the cylinders are made as shown in FIGURES 5 and 6.

Thus, referring to FIGURES 5 and 6, the

control cylinders

162 and 103 are interconnected by a fluid connection member 105 which includes the first and

second cylinder heads

136 and 136 which are joined by a fluid cross-member 137 in communication with both the

cylinder heads

136 and 136 through fluid ports 13% and 138'. A fluid inlet to the fluid connection 137 is provided at 146 for admitting fluid to each of the cylinders simultaneously and allowing removal of fluid from. the cylinders. A fluid outlet 141 is provided to allow the discharge of well fluid from the interior 142 of the well casing 1313 upon the upward stroke of the pump rod 131. Within the cylinders 102 and 1113 a first piston 144 and a second piston 144 are reciprocable and are interconnected by a cross-member 145 to assure their simultaneous movement. The cross-member 145 extends above the well head 132 and is interconnected with the pump rod 131 such that upward and downward movement of the

pistons

144 and 145 causes simultaneous upward and downward movement of the pump rod 131. The

pistons

144 and 144 terminate at their lower end in transversely extending piston faces 146 and 146' upon which fluid under pressure in the cylinders 102 and 1113 can operate to force the pistons upward. Thus, as fluid under pressure is forced into the cylinders 1&2 and 103, it progresses downwardly around the pistons 144 between the exterior of the pistons and the interior of the cylinders 1132 and 1&3 which is spaced therefrom. The fluid thus rogresses from the fluid inlets 138 and 133 downward to fill the cylinders and exert fluid pressure upon the piston faces 1% and 146. When the fluid within the cylinders 1 52 and 193 is pressurized sufliciently, the force upon the piston faces will raise the pistons and the pump rod 131 attached thereto to cause discharge of well fluid from the outlet 141 where it progresses through the well fluid conduit 147 through a suitable valve 143 and to a well fluid reservoir 149.

A control cam described more fully hereinafter is aifixed to one of the pistons 144 at the upper end thereof exteriorly of the cylinder and extends downwardly within the casing 134 substantially parallel to the control cylinder 1 12. The control cam is shown in detail in FIGURES 8 and 9.

Referring now to FIGURES S, 6 and 7, the apparatus of the present invention is shown for operating the fluid pump 99 from the first position at which the pump is in the condition where fluid is pumped through the conduit 123 as the outlet conduit, and from the reservoir 101 through the inlet conduit 124, to the second position at which the flow of fluid through the pump is reversed such that fluid flows to the pump through the conduit 123 and from the pump to the reservoir through the conduit 124. As discussed hereinbefore, movement of the pump from the first to the second position and from the second to the first position is achieved by exerting pressure upon the first piston H-i1 or the second piston H-2 respectively to move the slide block F of the pump to the required position. In the presently preferred embodiment this movement of the pump is obtained by utilizing an auxiliary fluid pump 1% affixed to the shaft A extending from the housing of the reversing pump 99'. The auxiliary pump 11111 supplies fluid at a pressure sufficient to actuate the pump from one position to the other position by pumping fluid under pressure into the respective cylinder to operate upon the piston H. In order to exert the fluid pressure at the required time in the cycle a 4-way fluid valve 2% is utilized to conduct fluid under pressure through the fluid line 201 or 2112, dependent upon the direction at which the slide block F of the pump is to be moved.

In order to operate the 4-way valve to reverse the direction of fluid flow through the main fluid pump 99, a push-pull cable 151 is utilized that has a flexible conduit 151a surrounding the same. This cable 151 at one end is aiflxed to the actuating rod 210 of the valve 200' while the opposite end of the cable 151 is aflixed to the rod 152 of the cam actuating apparatus as described more fully hereinafter and as shown in FIGURE 8. Push-pull cables of this type are well known to the art for many similar push-pull applications.

Thus, as shown in FIGURES 7 and 8, longitudinal movement of a push-pull rod 152' results in a corresponding movement of the cable 151 and the actuating rod 210 of the control valve 290 to move the fluid pump 99 from one position to the opposite position. The reversal mechanism which cycles the movement of the push-pull rod at the proper time with respect to the upward-downward movement of the pump rod 131 is shown in detail in FIG-

URES

6, 8, 9 and 10. The push-pull rod 152 is connected to and supported by a support lever 153 and is in turn connected to

cam follower rollers

154 and 155 such that horizontal movement of the cam folowers 154 and 155 in either direction causes the push-pull rod 152 to be moved therewith and the lever 153 to be moved through a substantially horizontal arcuate path. The reversal mechanism 153 is located as shown in FIGURES 6, 8 and 9 proximate the cylinder 102 such that the push-pull rod 152 extends in a substantially horizontal position. The cam bar 158 is a T-shaped beam with cams 1615* and 161 aflixed at opposite sides of the web 16 2 of the T beam as shown in FIGURES 8 and 9. The cam bar extends vertically and is aflixed at its upper end .163 to a bracket 164 which is in turn affixed to the piston 144 and the crosshead for movement upward and downward with the pump rod 131. The web 162 thus extends vertically and is oriented transverse to the axis of the push-pull rod 152. The cams 16d and 16 1 are aflixed at opposite sides of the web 162 and are triangular in configuration with an apex 166 and 167 respectively which projects outwardly from the surface of the web by an amount sufficient to cause the push-pull rod to move the 4-way valve and thus the pump from one condition to the other conaceaeev dition. At the lower end of the cam bar there is affixed a guide follower 170 which is a roller rotatably mounted upon a shaft 171 as shown in FIGURES 8 and 9 to retain the cam bar in vertical orientation during the upward and downward movement of the pump rod 131.

A vertically oriented guide 173 of rectangular crosssection having a depth greater than the width of the cam bar and a width substantially equal to the diameter of the guide follower 170 is rigidly connected to reversal mechanism 153. The guide 173 extends vertically within the casing 134 as shown in FIGURE 6. Thus, the cam bar and the guide follower 170 can move upward and downward in the guide means 173 with the guide follower in rolling contact with opposite sides thereof to maintain the cam bar in a vertical and aligned condition. The

cam followers

154 and 155 are afiixed to the push-pull rod 152 at the inner end 175 thereof by means of a channel-shaped bracket 176. The bracket 176 provides an offset mounting surface 177 to which the

cam followers

154 and 155 are rotatably aflixed with the transverse center line of the cam followers being substantially aligned with the axis of the push-pull rod 152. The axis of rotation of the cam followers 154 and #155 are spaced apart sufficiently that the opposed surfaces 178 and 179- of the cam followers which bear upon the cam bar 153 are spaced at a distance suflicient that one surface 178 is approximately in contact with one surface of the web 162 when the opposite cam follower surface 179 is at the position of the apex 167 of one of the cam lobes. Thus, the cam followers are spaced to allow horizontal movement of the push-pull rod 152 by a horizontal distance equal to the height of the cam lobe above the surface 162. A series of holes are placed through the web mateaole with the openings through

cams

160 and 161 such that the cams can be moved to various locations on the web to adjust the position of the

apexes

166 and 167. Thus, the cams can be moved toward one another and aflixed to the cam bar, or can be moved away from one another, or their positions can be changed independently.

Thus, the position of the pump rod 131 at which the cam 160 or the cam 161 causes the reversal of fluid flow from the fluid pump 99 can be varied through an infinite number of positions. As discussed more fully hereinafter, the pump will be reversed in direction when the apex 166 or the apex 167 passes between the

cam followers

154 and 155. The bracket 130 is aflixed to the guide means 173 and extends upward to a position at which it furnishes a mounting surface 181 for attaching a horizontal guide means 182. The horizontal guide means is a roller 132 rotatably afi'ixed to the bracket 181) and extends to a position substantially aligned with the

cam followers

154 and 155. The horizontal guide means 182 is mounted such that it extends into a horizontally extending groove 184 in an extending arm 185 of the bracket 175, with the diameter of the guide means 182 and the height of the groove 184 being such that the guide means 182 restricts the bracket 176 to horizontal movement with respect to the cam bar. A second bracket 190 is aifixed opposed to the first bracket 180 at the opposite side of the guide means 173 and substantially below the push-pull rod 152. A support arm 191 is pivotally aflixed to the bracket 190 by a pin 191a. The arm 191a is in turn aflixed at the upper end thereof to the push-pull rod 152 in order to support the rod and to allow movement thereof in a substantially horizontal although slightly arcuate direction. The upper and

lower cams

160 and 161 respectively as shown in FIGURES 8 and 6, are positioned on the cam bar at opposite sides of the web 162 thereof to provide reversal of the pump 99 at the desired upper and lower positions of the pump rod 131 during the stroke. The upper earn 160 is positioned on the cam bar such that the apex 166 of the cam passes beneath the cam follower 154 at the lowest desired position of the pump rod 131, while the lower cam 16 1 passes beneath the cam follower 155 with the apex 167 12 of the cam located at the position corresponding to the uppermost desired position of the pump rod 131.

Accordingly, it is required that the push-pull rod 152 be moved only when the lowermost and uppermost position of the rod 131 is achieved. That is, during the downward stroke of the pump rod 131 and the corresponding downward movement of the cam bar 158, the push-pull rod 152 will not change in position until the upper cam 160 contacts the cam follower 154. As the cam 169 moves downward between the cam followers 154 and it will force the earn 154 to the left in FIGURES 8 and 9 until the cam follower 154 and the control rod 152 have been moved the distance to the left corresponding to the apex 166. It is necessary that this position of the control rod 152 be maintained until the uppermost position of the pump rod 131 is reached.

Thus, referring now to FIGURES 6, 7 and 8, when the cam bar and reversal mechanism have caused the actuating rod 152 in FIGURE 8 to be moved to the lefthand from the position shown in FIGURE 8 as a result of the cam follower 154 passing over the apex 166 of the upper cam 160, the fluid pump 99 is moved to the position at which it is to pump fluid under pressure into the cylinders 192 and 103 to raise the pistons 144 and 144' and the pump rod 131. That is, when the upper cam 161 on the cam bar positions the push-pull rod 152 to the left, the pump is moved to the position at which the fluid conduit 123 is the outlet of the fluid pump and the fluid conduit 124 serves as the inlet. At this position, therefore, fluid is pumped from the reservoir 1111 through the fluid pump 99 and into the cylinders 102 and 1413 to act upon the piston faces 146 and 146' and raise the pistons 144 and 144' together with the pump rod 131. When the pump rod 131 has reached its uppermost position, the lower cam 161 on the cam bar 158 passes beneath the cam follower 155 and moves the push-pull rod 152 to the right as described hereinbefore. Movement of the push-pull rod 152 to the right causes the position of the 4-way valve 200 to be moved to the position whereby fluid is pumped from the cylinders 192 and 1133 and back into the reservoir such that the fluid conduit 123 acts as the fluid inlet to the pump, while the fluid conduit 124 acts as the outlet from the pump to the reservoir. A typical stroke length of the pump rod 131 is three feet.

The pump 100 has a suction line 204 leading therefrom to the interior of pump 99. Liquid is constantly withdrawn from pump 99 through line 204 and discharged from pump 160 through a conduit 205 to a T fitting 207. Two conduits 269 and 211 extend from T 207. Conduit 209 is connected to the inlet side of a back pressure valve 213, which valve has a discharge conduit 215 leading therefrom to one leg of a T 217.

T 217 is connected by conduit 263 to the interior of pump 99. Another leg of the T 217 is connected to a conduit 219 that extends to a third T 221. T 221 is connected to two

conduits

223 and 225 which extend to two liquid discharge ports formed in the valve 200. Liquid under pressure from the pump 100 is supplied to the valve 200 through the conduit 211 that extends to a liquid inlet port formed in valve 200, as may best be seen in FIGURE 7. The liquid in conduit 211 will be at whatever pressure the back pressure valve 213 is set for. The back pressure valve 213 is set for a pressure higher than that at which pump 99 discharges liquid through the conduits O and 123, as shown in FIGURES 5, 6 and 7. When the cable 151 moves to the left as the rod 131 completes its downstroke, and the cam lobe 166 contacts the follower 154 (FIGURES 6 and 8), the valve member 210 moves to the left to so position valve 200 that liquid discharges from valve 200 through conduit 202. Flow of liquid under pressure through conduit 202 to the valve 99 causes the yoke F to move upwardly towards the upper right-hand corner as shown in FIGURE 2, with fluid being withdrawn from the reservoir 101 through the conduit 124 and conduit P intothe confines of pump 99. Due to the counter-rotation of the rotor B and blades 13 D, the fluid withdrawn from the reservoir is discharged through the conduits O and 123 to force the rod 131 upwardly as previously described in detail.

The pump 99 so continues supplying fluid to cause upward movement of the rod 131 until the rod approaches the upper extremity of its stroke, whereupon the cam lobe 167 (FIGURE 8) contacts the cam follower 155 and moves the cable 151 and rod 210 to the right to alter the position of the valve 200. In this new position, the valve 200 directs the flow of liquid under pressure from the pump 100 through conduit 201 to the pump 99, with the pressure of this liquid exerting a force on one of the pistons H as shown in FIGURE 2, to cause the yoke F to shift downwardly and to the left, with liquid then being withdrawn by pump 99 from the conduits 123 and O to be discharged through the conduits P and 124 into the reservoir 101. As liquid is withdrawn from conduits 123 and O, the rod 131 moves downwardly by gravity, and the rate at which rod 131 moves downwardly is dependent entirely on the rate at which the pump 99 withdraws fluid from the conduits 123 and O to discharge the same back into the reservoir 101. Valve 200 is of such internal structure that when liquid is discharged through

conduits

201 or 202 to move the yoke F in pump 99 from one position to another therein, the conduit through which liquid is not being discharged to the pump is placed in communication with either the

conduit

223 or 225, and liquid can then flow to the T 221, conduit 219, T 217, and conduit 203 back into the confines of the pump 99. The direction of flow of the liquid in the conduits associated with the pump 100 and valve 200- is indicated by arrows in FIGURE 7.

A shut-off valve 124a that is normally open is disposed in conduit 124. A second shut-off valve 123a which is normally closed is disposed in a lateral line 123b that is in communication with conduit 123 and the lower interior of reservoir 101. By closing both valves 124a and 123a, work can be performed on pump 99 without losing the air pressure in reservoir 101.

In order to obtain a balanced hydraulic-pneumatic system the reservoir tank 101 is filled with sufficient fluid to transmit the fluid from the reservoir 101 into the

cylinders

102 and 103 in sufiicient quantity and under suflicient pressure to raise the pistons 144 and 144' the required distance under the load exerted upon the polish rod. Air under pressure is, however, maintained within the reservoir 101 above the supply and the pressure of the air is maintained sufiiciently high to obtain a balancing force upon the fluid. That is, a typical polish rod load is 11,000 pounds and the system of the present invention furnishes a balancing load of 7,500 pounds, such that it is necessary that the pump exert a force equal to the differential between the air pressure above the fluid and the pressure upon the fluid and the cylinders necessary to raise a load of 11,000 minus 7,500 pounds.

Thus, in the presently preferred embodiment an air compressor 231 of the type well known to the art is mounted above the reservoir 101 with an air outlet from the compressor directly connected into the reservoir 101. The compressor is driven by the motor 230 which also drives the shaft A of the fluid pump through a clutch 232 shown in FIGURE 11. The clutch 232 is utilized to drive the compressor 231 by means of the prime mover 230 which furnishes the rotating power for the fluid pump 99 as shown in FIGURES and 6. Since the air compressor is utilized to maintain the pressure within the reservoir 101 at a predetermined level the clutch is of a type which will actuate the compressor when the air pressure within the reservoir drops below the predetermined pressure level. Thus, an air line 233 is connected between the air space above the fluid level in the reservoir and the clutch actuating means 234. The motor shaft A is constantly rotating and the fly wheel 236 rotates therewith. The clutch surface 237 of the fly wheel is mateable with a clutching surface 238 of the clutch such that when the two surfaces 237 and 238 are brought into pressure engagement the motor shaft A will cause the compressor shaft 237 to rotate by rotating the clutch plate 239.

The clutch shaft 240 is suitably supported in a bearing 241 which is aflixed to the upper surface of the reservoir 101 by means of a bracket 242. The clutch plate 239 rotates with the clutch shaft and is directly connected to the compressor shaft. The clutch plate 239 includes a longitudinally stationary plate 244 and a longitudinally movable plate 245 with a clutching plate 246 positioned longitudinally therebetween and extending radially therebeyond to define the clutching surface 238 of suitable material. The movable plate 245 is longitudinally movable along a sleeve 248 afiixed to the shaft 240 and is urged toward the stationary plate 244 by means of springs 250 which are circumferentially spaced around the mated plates and mounted upon studs 251 in compression such that the springs urge the

plates

244 and 245 together to thereby compress the clutch plate 246 therebetween .for rotation of the clutch plate 239. The sleeve 248 defines a radially extending shoulder 253 mated wtih the inner surface of the movable plate 245 such that movement of the sleeve 248 away from the stationary plate 244 causes the movable plate 245 to be moved away from the plate to release the clutching plate 246. Thus, when the sleeve is moved away from the stationary plate 244 the clutch is disengaged, while when the sleeve is allowed to move toward the stationary plate 244 the clutching surface 238 is moved into engagement with the rotating clutching surface 237. A second sleeve 260 is positioned surrounding the shaft 240 and the first sleeve 248 and is radially spaced from the shaft and sleeve 248 by a substantial distance. The sleeve 260 is free to move longitudinally but is restricted from rotational movement by means of a stud 261 which extends into an opening 262 in the bracket 242. The stud is movable longitudinally within the opening 262 but is prevented from rotation.

A roller bearing assembly 263 is positioned between the sleeve 248 and the outer sleeve 260 to allow relative rotation of the sleeve 248 with the shaft 240. The bear ing assembly 263 is longitudinally aflixed with respect to the sleeve by means of snap rings 264 and 265. An actuating sleeve 270 is affixed surrounding the shaft 240 and defines a pressure face 271 which extends radially outward to the outer sleeve 260. The actuating sleeve is stationary longitudinally and is atfixed to the bearing 241. Seals are provided to define a relatively air-tight chamber 275 between the face 271 and the rearward face of the outer sleeve 260. The outer sleeve is longitudinally movable with respect to the actuating sleeve 270 such that when air under pressure is forced into the chamber 275 the outer sleeve 260 is move-d longitudinally away from the face 271 of the actuating sleeve 270. Thus, in FIGURE 11 the outer sleeve 260 is caused to move to the right. Movement of the sleeve to the right causes the bearing assembly also to be moved to the right as well as the sleeve 248. Movement of the sleeve by means of the shoulder 253 causes the clutch plate 245 to be moved to the right and allows the clutch to be disengaged by letting the clutching surface 238 move away from the clutching surface 237. Thus, when the pressure falls below a predetermined minimum level the spring action of the clutch causes the clutch to engage and rotate the compressor with the rotor shaft A. When the pressure builds up to the predetermined level the clutch is then disengaged.

What is claimed is:

1. An apparatus for vertically reciprocating a loaded rod at a desired first uni-form rate on the upstroke and a desired second uniform rate on the downstroke by a hydraulic liquid under pressure, including: a vertical cylinder disposed adjacent said rod; piston means upwardly and downwardly reciprocable in said cylinder as said liquid is discharged into said cylinder at a first pressure and discharged from said cylinder at substantially a second pressure; means for connecting said rod to said piston means; a reservoir that is partially filled with said liquid and a quantity of air under such pressure that said liquid is at all times under no less than said second pressure, with said second pressure being of such magnitude that when said piston means is subjected to said liquid an upward force is exerted on said piston means that is equal to the weight of said rod'p'lus a predetermined percentage of said load on said rod; a reversible variable volume pump having first and second ports through either of which liquid can be discharged when said pump is rotated, said pump having a slide block that is capable of being disposed in a first oifcentered position, a centered position and a second ofifcentered position, with liquid being discharged through said first port at a first rate when said slide block is in said first position and through said second portat a Second rate when said slide block is in said second position, with no discharge of liquid from said pump taking place when said slide block is in said centered position;

first and second pipes, which first pipe connects said first port to the interior of said cylinder and said second pipe connects said second port to the interior of said reservoir; first hydraulic means for selectively moving said slide block to either said first position where said pump when rotated at a constant speed discharges said liquid from said reservoir to said cylinder to raise said piston means and rod at said first rate, or to said second position where said pump discharges said liquid in said cylinder back to said reservoirto lower said piston means and rod at said second rate; first conduit means for defining first and second paths for hydraulic liquid under pressure to said first hydraulic means, which hydraulic liquid when discharged to said first hydraulic means through said first path causes said slide block to move to said first position, and when said hydraulic liquid is discharged through said second path said slide block is caused to move to said second position; first valve means connected to said first conduit means, with said first valve means when in a first position being capable of discharging said liquid under pressure to said first conduit means to follow said first path and when in a second position being capable of discharging said liquid under pressure to said first conduit means to follow said second path; second conduit means for supplying said liquid under pressure to said first valve means; means for moving said first valve means to said first position when said rod completes a downstroke and to said second position when said rod completes an upstroke; a first pump having the discharge thereof connected to said second conduit means with the suction of said first pump communicating with said liquid in said reservoir; an air compressor; a clutch for driving said air compressor; a prime mover; means for transmitting power from said prime mover to said variable discharge pump, to said first pump, and to said clutch; third conduit means for connecting the discharge of said compressor to the upper interior of said reservoir; and means for moving said clutch to a position where said clutch does not drive said compressor when said air pressure in said reservoir rises substantially above said second pressure, with the rates at which said piston means and rod move upwardly and downwardly being determined by the rates at which said variable discharge pump discharges said liquid from said reservoir to said cylinder and from said cylinder to said reservoir when said slide block is in said first and second positions respectively.

2. An apparatus as defined in claim 1 wherein said means for moving said first valve means comprises an elongate cam member that moves upwardly and downwardly with said rod, said cam member having two longitudinally spaced outwardly extending lobes; and further includes a cam follower that moves substantially normal relative to the direction of movement of said cam when contacted by one of said lobes; and an elongate member extending between said follower and said first means, with said elongate member moving concurrently with said follower, and said elongate member alternately moving said first valve means to said first and said second positions as said follower is contacted by said lobes.

3. An apparatus as defined in claim 2 wherein the surfaces of said lobes which contact said follower are angularly disposed relative to the longitudinal axis of said cylinder, with the degree of said angularity determining the rapidity with which said valve means Will be moved from said first to said second position and vice versa.

Aller et a1 July 21, 1953 Smith Aug. 2, 1960