US2366777A

US2366777A - Hydraulic lifting mechanism

Info

Publication number: US2366777A
Application number: US385812A
Authority: US
Inventors: Ralph C Farley; J W Gillespie
Original assignee: Individual
Current assignee: Individual
Priority date: 1941-03-29
Filing date: 1941-03-29
Publication date: 1945-01-09
Anticipated expiration: 1962-01-09

Description

Jan. 9, 1945.

Filed March 29, 1941 5 Sheets-Sheet Raoh C. Far/ey d. W Gif/@spie Jan- 9, 1945. R. c. FARLEY ET AL Y HYDRAULIC LIFTING MECHANISM Filed March 29, 1941 5 Sheets-Sheet 3 mmmwmmum lll@ Jan- 9, 1945. R. c. FARLEY ET AL 2,365,777

HYDRAULIC LIFTING MECHANISM Filed MalCh 29, 1941 5 Sheets-Sheet 4 s w 34 34 S v52 35" 48 56 l 35 55 53 '44 QA 442 7 46 I 46 I I :445

Patented Jan. 9, 1945 UNITED STATES PATENT foFricE 2,366,717 v HYDRAULIC LTFTING MEoHANlsM Ralph C. Farley and J. w. Gillespie,

Henderson, Tex.

\Application March 29, 1941, Serial No. 385,812

3 Claims.

This invention relates to new and useful improvements in hydraulic lifting mechanisms.

`One object of the invention pis to provide an improved mechanism for operating the usual reciprocating well ptunp, which mechanism is actuated by a, pressure fluid and is preferably located at the surface of the well, but which may 'be dispo-sed below the surface.

An important object of the invention is to provide anA improved hydraulic lifting mechanism,

wherein a reciprocating piston which is arranged equal on both the upstroke and downstroke so as to require the same amount of power and also whereby the operation of the mechanism is more uniform and smoother.

A particular object of the' invention is to provide an improved hydraulic lifting mechanism,

of the character described, wherein the shock of the upstroke of the operating piston is eliminated by reducing the amount of pressure fluid admitted to said piston; there being other means provided for absorbing the shock of the downstroke of the piston., l

A further object of the invention is to provide an improved hydraulic lifting mechanism whereinthe admission of pressure uid to the piston is `controlled by a snap-action valve which is actuated by the movement of said piston and which in turn controls the direction of movement or stroke of the piston by changing the direction of flow of the pressure ujd. Y

Still another object of the invention is to provide an `improved hydraulic lifting mechanism which isoperated by a closed pressure fluid system, the mechanism being so arranged that the small amount of fluid exhausted or displaced may Ibe easily an'd readily returned to the source of supply, whereby an economical, ecient, recipv rocal lifting mechanism is" provided.

A still further object of the invention is to provide an improved hydraulic lifting ,mechanism, of the character described, which may be actuated by a centralso'urce of fluid pressure, whereby'two or more mechanisms may be operated by one power unit so as to reduce operating and maintenance costs.

l Yet, another object of the invention is to provide an improved hy raulic lifting mechanism, of the character descr' ed, wherein the counterbalancing means is si arranged that the same may be adjusted to co 'pensate for fluctuations of the flow of the well ui-d from the formation into the working barrel `of the pump, whereby a smooth and uniform operation of the mecha-` nism is assured.

A furthe-r object of l'the invention is to` provide improved counterbalancing meansfor a hydraulic lifting mechanism which may be actuated by an artificial pressure fluid or by the pressure of well fluid which is within the well casing of the well being pumped. i

A construction designed to carry out the inventionwill be hereinafter described together with other features of the invention.

The invention will be more readily understood from a reading of the following specification and by reference to the accompanying drawings, in which an example of the invention is shown, and wherein:

Figure 1 is a View, partly in elevation and partly in section, of a hydraulic lifting mechanism constructed in accordance with the invention, f

Figure 2 is a view, similar to Figure 1, showing the mechanism in its position during the downstroke of its piston.

Figure 3 is a transverse, vertical, sectional view, on an enlarged scale, of the upper portion ofthe mechanism,

l Figure 4 is a continuation of Figure 3, showing the central portion of the mechanism,

Figure 5 is a continuation of Figure 4, showing the lower portion of the mechanism.

Figure 6 is an enlarged, transverse, vertical, sectional view of the control valve, showing the same in its lowered position during the upstroke of the piston,

Figure'? is a similar view of the valve inits raised position during the downstroke of the piston,

Figure 8 'is a horizontal, cross-sectional view taken on the line 8--8 of Figure '1,

Figure 12 is a schematic view, showing two lifting mechanisms connected to the same source v 225,504, led August 18, 1938, now Patent No.

In the drawings, the numeral I designates the usual wellcasing having a string of tubing II extending therethrough. The conventional pump rods I2 depend axially through the tubing and are connected to the plunger of a well pump (not shown), which is mounted in said tubing. The'improved lifting mechanism A is arranged to be` mounted at the surface of the well on suitable brackets or supports I3 above the customary ow T I4 and pump rod stuiiing box I5.

I he mechanism includes a short, upright' cylinder I6, having an angular collar I1 welded or otherwise secured to its exterior adjacent its lower end, whereby it may be fastened by suitable bolts I 8 to the brackets` I3. The upper end ofl the cylinder I6 is connected by a stuiling box I9 to the lower end of an elongate,A cylindrical sleeve which is of substantially the same diameter so as to form a continuation thereof. A reduced, upstanding collar 2| is preferablyr made integral with the upper end of thestuifing box -I9 and, as is clearly shown in Figure 4, the collar is of smaller diameter than the sleeve 2li and is disposed within its lower end. A cylinder 22 extends axially substantially throughout the length of the sleeve and has its lower end snugly engaging over the collar 2|. The diameter of the cylinder 22 is smaller than the diameter of the sleeve 20 to provide an annular space 23' therebetween.

A piston 24 is mounted to reciprocate within Athe cylinder 22 and is connected to a counterbalance piston 2S slidably disposed within the cylinder I6 by an inter-connecting piston rod 25 which extends through the stuffing box I9. A

coupling 21, carried by the upper end of the pump rods I2, fastens said rods to' the depending rod 28 of the piston 26, whereby the rods I2 are connected to said piston and the piston 24. A reduced, depending skirt 29 is made integral with the lower end of the piston 24 and.co-acts with one or more cushioning slots 30, formed in the lower end of the cylinder 22, to absorb the shock and to assure a smooth downstroke of said piston. The slots 30 are substantially keyshaped, being enlarged and circular at their upper ends, and establish communication between the borev of the cylinder 22 and the annular space 23.

For admitting fluid under pressurev to the annular space 23, a suitable inlet pipe 3| is connected to the upper end of the sleeve 29. The

` pressure of this iluid is` utilized to reciprocate the piston 24 so as to raise and lower the pump rods I2 and pump plunger (not shown) attached thereto for liftingV the natural well iluid to the surface. In order to elevate the piston 24, the fluid pressure flows from the annular space 23 through the slots 30 into the cylinder 22 beneath Athe peripheral upper portion of the said piston. After the piston has completed its upstroke, the pressure of the uid will be exerted upon the upper end of said piston to force the same downwardly. It is pointed out that the end portion of the downstroke of the piston will be cushioned by the co-action of the slots 30 and the skirt 29 of said piston. As the downstroke begins, the piston moves downwardly in its. cylinder and the skirt thereof forces the fluid therebelow from the cylinder through the slots 3D. Since the enlarged upper ends of the slots are wide open, there is substantially no restriction of the escaping fluid at this time, with the result that the downward movement of the piston at the start of the doWns'troke is comparativelyl rapid. This comparatively rapid downward movement continues until the skirt 29 moves opposite the upper ends of the slots and, as soon as this occurs, the skirt co-acts with,the slots' to reduce the cross-sectional area of the slots 3l), and thereby retrict the escape of fluid. This restriction 'of the escaping iiuid causes the lowering of said piston and pump rods attached thereto to be gradually slowed until the piston and rods finally stop at the end of the downstroke. Thus, smooth operation is assured. Itl is noted that the cross-sectional area of the cushioning slots controls the speed of descent at the lower portion of the downstroke and that the time ofl the downstroke may be regulated, to an extent, by varying the area or size of said slots.v

The upper end of the sleeve 20 is screwthreaded onto a reduced collar 32 which depends from an annular valve body 33, the body having its upper end connected tothe lower end of an elongate cap or housing 34 by a suitable coupling 35.y The valve body 33 is provided with an axial bore 36 which has its lower extremity enlarged as shown at 31. A tubular valve member 38 is slidable in the bore 36 and is formed with an external, radial flange or shoulder 39 adjacent its lower end as shown in Figure 6. The lower portion of the valve member 38 below the ilange 39 is preferably reduced in diameter and the enlarged undersurface of said ange is bevelled to provide an amplified seating surface .40.

An upstanding collar 4 I, complementary to the collar 32 of the valve body 33, is screw-threaded y l into the upper end of the cylinder 22 and en gages within the bore of said collar 32 as shown in Figures 6 and 8. The upper end ofthe collar 4I is internally screw-threaded so as to receive a valve s eat 42 which is complementary to and is arranged to be engaged by the bevelled surface 40 of the valve member 38 (Figure 6). In order to establish communication between the enlarged' bore 31 of the valve body 33 and the annular space 23 and inlet pipe 3|, a plurality of angular slots or openings 43r are formed in collar 4I (Figure 8). A collar v44 is screw-threaded into the lower end of the coupling 35 and depends within the bore n36 of the valve bodyv to provide a valve seat which is arranged to be' engaged by the upper end of the valve member 38, as is clearly shown in Figure 7. Immediately below the collar 44, an enlarged annular groove or channel 45 is formed in the bore 36 of the valve body and this groove communicates with a suitable outlet or exhaust pipe 46. f

When the valve member is in engagement withn the seat 42, its upper end is spaced from the seat 44 and a ilow of pressure fluid from theannular space 23v between the cylinder 22 and sleeve 20 posed within the lowersleeve 52,

intolt'beupper end of said cylinder is prevented. However, the iluid` within the annular space 23 may ow through the cushioning slots 30 intothe lower end of the cylinder so as to lift thepiston l24 (Figure 2). As the valve member moves up- I.'wardly from the seat 42 to engage theseat 44, communication between the annular space 23 and the upper end of the cylinder bore, is established in FigureZ, the fluid entering the upper end of the cylinder is applied to the piston 24 so as to force the same downwardly. To eiect the escape of the fluid between the valve member and the seat 44 on the upstroke of said member, the extreme upper end of the same is reduced in diameter as. shown at 41 toprovide an annular space or clearance between the member and the bore 36 of the valve body, whereby fluid -may bleed into the groove 45 and pipe 46. This arrangement obviates the possibility of a pressure remaining above the valve member 38 and assures that the pressure below said valve will hold the same in engagement with the seat 44. It is pointed out that the depending portion of the valve member below the seating surface 40has a snug sliding t within the bore of the collar 4| and not only serves as a guide for said member but also tends to maintain said collar bore closed after said seating surface has moved away from its seat 42 until the groove 45 and pipe 46have been substantially closedby the upper portion of the member.

inder until after the shutting olf of the exhaust pipe and groove, whereby unnecessary discharge of uid is avoided andthe occurrence of a balanced condition prevented. l

From the foregoing, it is readily apparentthat the valve member 38 controls-the admittance to and exhaust of 'fluid from the interior of the cylinder 22 and, as explained, vthis fluid is under pressure Vso as to actuate the piston 24. A piston `rod 48, of less diameter than" the rod 25, is con"` nected to the upper end of the'piston and extends axially through the cylinder 22,' tubular valve member 38 and elongate cap 34. For guiding the tion `to theV other to` reciprocate `the piston 24, as

has been hereinbefore described, an elongate sleeve 52 is slidably mounted on the upper end of the piston rod adjacent the guide member 50, being supported vby a collar 53 which is secured to said rod` (Figure 3). The upper end of the sleeve 52 telescopes thelower end of a second elongatesleeve` 54 which surrounds tjhero-d.` A coiled spring 55 surrounds the rod and is diss 4 with its upper endengaging the lower'edgeof the upper sleeve 54. The lower end of the spring 55:,rests upon an internal, annular shoulder 56 formed at the Thus, no appreciable quantity of 1- uid is admitted into the upper end of the cyl--` lower en d `of the lower sleeve and exerts its pres-l sure to` constantly urge the telescoping sleeves apart. Separation of the'sleeves 52 and 54 is preventedby a collar-51 carried by the rod an obviously, the spring 55 normally holds the upper 1 sleeve 54 inlengagement with the` collar 51 as shown in Figure 3.

as shown at 58, whilean annularflange 54a is formed on `theuppfr extremity of the sleeve 54 The telescoping sleeves52 and 54` are utilized to lower the-valveA member-38 at the (Figure 3) will be hereinafter explained.

For raisingthe valve member` at the completion of the upstroke of the piston, an elongate sleeve 59, similar to the sleeve 54, is` slidable on the ,lower` end, of the piston rod 48 above. said piston (Figures 3 and 4), being supported by a collar 60 which is secured to said rod. The upper end of the sleeve 59 is telescoped bythe lower end completion of the downstroke of thepiston 24, as

of a second elongate sleeve 6|, which is similar to the sleeve A52. `A coiled spring 62- isconiined` within the bore of the sleeve 6| between the upper end of the sleeve 59 and ansleeve 6|. The spring urges the sleeve 6| into engagement with'a collar 64 carried by the piston rod 48, whereby said sleeve and the sleeve 59 are constantly urged apart. The upper extremity of the sleeve 6| upper end of the end of the sleeve 59 and,` collar 60 as shown in Figure 4.

internal ribs 49 of collar 53 the ribs thevalve member 38. The is within the axial opening formed by valve'member, which lowering occurred. space 23 may flow through the slots lower end of the cylinder 22 to raise the piston24, as has been hereinbefore explained. ton moves upwardly, -the `pistony rod 48 travels therewith, thereby raising the sleeve 52'away from the upper ribs of thevalve member. The pressure of the spring 55 moves theV sleeve imsaid sleeve remains in this downstroke is completed,

As the upstroke continues, the

sleeves

52 and 54 are moved upwardly away from the valve mem`` this occurs,

ber, while the sleeves said member. During the upstroke, the pressure of the lfluid isacting `against the effective crosssectional area of the valve member, this area being the `upper surface `of the external ilange'39. Thus, the member tion engaging the' the collar 64 above the sleeve 6| enters the axial opening. formed by the lowerinternal ribs-"49 of andthe-'externashouieres of Whenv sleeve` the nuid holding said sleeve engages said ribs` (Figure 6).

Afurther movement of the upper 6| isresisted bythe pressure ofthevalve member seated,'and continued upward movement of the piston an upward movement or telescoping of the lower Asshownin Figure 7, the extreme lower end of the sleeve 52 is enlarged l internal,` annular Y shoulder 63 formed at the upper .end of said 4is enlarged to forml an external,` annular shoulder 65 `as shown'in Figi ure vEi. An annular ange -59a,"similarfjtothe flange 54a of the sleeve 54, is formed on the lower f normally, engages the" and is spaced from the-sleeve, having `been moved to this position on the lowering ofl the has j ust' previously j `The pressure uidwithin Ythe annular 30 into the As the pis.- l

with the -collar 53 and" position until the,l

59and 6| aremoved toward 38 is held Vin its lowered posiseat 42 as shown in Figure 6l As the piston approaches the yend of its upstroke,

24 and itsl rod 48 causes sleeve 68 relative-to said upper sleeve. This results in a compression of the coiled spring-62 confined between the sleeves, which spring is acting to urge the sleeve 8| upwardly. This compression of the spring continues until the annular flange y said member upwardly away from its seat 42. As

soon as this occurs, the tension of the compressed spring is added to the fluid pressure to rapidly move the valve member upwardlyinto engagement with the seat 44, whereby a snap action is imparted to the movement of said member.

As soon as the valve member is moved to its raised position (Figure '1) the'valve seat 42 is uncovered to permit the pressure fluid to flow from the annular space 23, through the slots 43 `and enlarged bore 31 into the upper end of the cylinder `22 t0 force the piston 24 downwardly. Since the lower end of the rod 26 is not exposed to the iluid pressure as is the upper-end of the rod 48, the effective cross-sectional area of the upper end of the piston is greater than that ofI its lower end.

Thus, when both ends of the piston are exposed to the pressure of the fluid, said piston will be lowered- It is pointed out that during the upward movement of the valve member, the depending portion of said member which engages within the bore of the collar 4I maintains the same closed to prevent fluid from entering the cylinder 22 untilvthe exhaust pipe. 46 and groove 45 are closed by the upper end of the member. During the downstroke of the piston, the valve member -is held in its raised position by the pressure exerted against and acting upon the lower end of s'aid member. Y

The downstroke of the piston 24A and its rod 48 continues until the lower end of the sleeve 52 strikes the upper internal ribs of ythe valve member and the coiled spring 55 is compressed so as to permit the annular ange 54a of the sleeve 54 to engage the upper end of said sleeve 52. When this occurs, the member 38 is returned to its'low ered position by the forcelof the fluid pressure exerted against its upper end and the compression of the spring 55 to again shut off communication between the annular space 23 and the upper end of the cylinder bore, whereby the pressure of said fluid will be exerted against the lower end of the piston to raise theA same. It is noted that the downstroke of the piston will be cushioned by the co-action of the depending skirt 29 of said piston and the cushioning slots 30. The provision of the telescoping sleeves above and below the valve member 38 makes it possible to operate said member with a snap action and thereby effect a change in the direction of movement of the piston 24.

For aiding the snap action of the valve member and for holding the same in its raised and lowered positions, a frictional resistance in the form of a spring-pressed ball 66 is mounted in a radial opening 61 formed in the upper end of the valve body 33. The ball is arranged to engage an annular groove 68 formed in the exterior of the valve member intermediate its ends, as is clearly'shown in Figure 6. It is manifestthat the frictional resistance occasioned by the engagement of the ball 66 in the groove 68 must be overcome before the valve member may be moved upwardly and, thus. this frictional resistance is added to the pressure acting downwardly on the upper surface l 4 assen?? of the external flange 89 o! said member and resisting upward movement of the member by the coiled spring 62. A second annular groove 88, below the groove 68,.receives the ball 86 after the valve member has been moved toits raised posi tion (Figure '1) to aid in the resistance of the downward movement of said member. However,

it is noted that the spring-pressed ball 66 may be omitted as thev snap action arrangement which is assisted by this frictional resistance is unessential to the operation of the valve member. It is also possible to dispense with the telescoping sleeve below the valve member.

From the foregoing, it is readily apparent that thepiston 24 is reciprocated in the cylinder 22 by an auxiliary pressure fluid, the introduction of which is .controlled by the valve member 38. For conducting the pressure fluid to the inlet pipe 3i and the annular space 23, a suitable pipe 10 is connected to said pipe 3l and leads to a source of supply (not shown). The exhaust pipe 46 also communicates with the source of supply by means of a pipe 1l. whereby the fluid exhausted from the lifting mechanism may be returned to said source. ,A `control valve 12 is mounted in the pipe 10 for regulating the amount of fluid admitted to the annular space 23 and includes a valve body 13 having a transverse partition 14 formed therein, as shown in Figure 10. The partition is provided with an opening 15 within which a cylindrical valve member or plunger 16 is movable. A diametrically-extending notch or slot K11, which is V-shaped, is formed in one end of the plunger 16, and, manifestly, as the plunger is reciprocated within the openingv 15, more or less. of the slot is exposed to the flow of fluid, wherebyrthelflow area through said opening and past the partition 14 is controlled. A valve stem 18 is connected to the other end ofthe plunger 16 and extends laterally from the valve body 13 so that it may be connected by a coupling 19 to an operating rod which projects into the cylinder i6 of the lifting mechanism. Suitable stuffing boxes 8l and 82 surround the valve stem 18 and operating rod 80, respectively. The inner end of the rod 80 is provided with a roller or wheel 83 which is spaced from the exterior of the piston rod 25 of the counterbalance piston 26 (Figure 4). A collar 84 is adjustably mounted on the rod 25 above the piston and is provided with an annular, upwardly and outwardly inclined surface 85 so as to serve as a cam for actuating the rod 80. When the piston 26 moves to its upper position, the roller 83 of the rod 80 will be engaged by the bevelled surface 85 of the collar 84, whereby said roller will ride upon said collar so as to gradually force said rod and the plunger 16 to the position shown in Figure 2;

With the plunger 16 in the position shown in Figures 1 and 10, the inner portion of the V-nbtch or slot 11 is exposed to the fluid `arida flow of fluid through the opening 15 is permitted. In this position, the uid flowing through the slot from the line 18 is substantially unrestricted as` the area of the slot is substantially the same as the cross-sectional areay of the line. If the plunger is moved through the openingv to the left in Figure 10 by the cam collar 84 engaging the roller 83 of the rod Bil, flow through the valve will be restricted and partially shut olf as shown in Figure 2. By adjusting the coupling 19, the combined length of the ystem 16 and rod 80 may be varied to alter the by-pass area of the notch 11 and thereby vary the quantity of fluid flowing through the opening 15 of the valve body. A nut l the parts of the valve 12 will be in the position shown in Figures 1 and 10 to permit a substantially unrestricted flow of fluid through the body 12 of said valve to the pipe 3|, annular space 23 and cylinder 22 to raise saidpiston. As the piston approaches the end of its upstroke, the bevelled surface 85 of the upwardly moving collar 84 will engage the roller 83 of the rod 80 to force the plunger 16 outwardly to the left in Figure 1. Due to the V-notch or slot 11, ow through the valve body will be gradually restricted so as to decelerate the speed of the upstroke of the piston. Whenthe piston reaches the upper end of its stroke, the plunger 16 will have been moved to the position shown in Figure 2 to restrict and partially-.cut off the flow of fluid through the valve body so as to cushion the upstroke of said piston. Thus, the upstroke of the piston is cush-V ioned to prevent the occurrence of a shock or jar. Assoon as the roller 83 is disengaged from the collar 84, thepressure of the fluid will move the plunger 16 to its open position to permit an increased ow through the flow to the annular space 23. Obviously, this increased ow will accelerate the downwardly moving piston. Since it is virtually impossible to ac-curately adjust an automatic valve of the type hereindescribed, a small tube 81 is connected in the pipe 10 and bypasses the valve 12 for conducting a predetermined amount of pressure uid to the annular space 23. The by-pass tube, which has a manual control valve 88 mounted therein, may be used for ne adjustments or may be put into use to compensate for wear inthe valve 12 or some of its parts.

4The lower end of the cylinder |6 is connected by a swaged coupling collar 89 to a T90 which has a` stulng box79| `depending therefrom for packing off aroundthe pump rods I2. The T' 90 communicates with the pipe 10 through a small tube 92, having a hand valve 93 mounted therein for admitting the pressure fluid to the `cylinder I6. A suitable tank 94 is also connected to the T by means of, a pipe 95, having suitable hand valves 9G and 91 mounted therein, and air under pressure is preferably stored in the tank. For lubricating the vcounterbalance pistonv26 and the bore of the cylinder I8, a predetermined fluid or liquid level is maintained in the tank 94 as shown by the dotted line in Figures 1 and 2. This fluid may be introduced into the tank from the pipe 10 by means of the tube 92 and pipe 95. After weight of the uid column or load is required.

` On the downstroke of the piston 24, the pressure of the fluid is the same and, need be only sufficient tov overcome that portion of the uair pressure in excess of the weight of the `sucker rods and pump plungensince the remainder of said air pressure offsets or is balancing said rods and plunger. Due to. the provision of this counterbalancing apparatus', a low operating pressure may be utilized to actuate the piston 24, whereby the natural fluid may be economically lifted to the surface. Obviously, since the same pressure or force isemployed inlowering the piston 24 as in raising the same, a smooth uniform operation or reciprocation thereof is assured with minimum wear.`

In order to accommodate fluctuations inthe volume or weight of the fluid column being lifted by the pump plunger, a by-pass pipe 98 is 4-connected in the `pipe 95V between the valve 91 and T 90 on either side of the valve 9B. A check valve 99 is mounted in the by-pass pipe 98 for preventing a flow of the counterbalancing fluid from the tank 94 to the cylinder I6 and for permitting an unrestricted flow in the opposite direction from said cylinder to said tank. Due to the provision of the by-pass pipe and check valve, the valve 96 may be adjusted to restrict the ow of the counterbalancing fluid through` the pipe 95 so as to control the rate of such ow.

-upstroke is controlled by the adjustmentof the valve 96, while the downstrokeis controlled by vthe counterbalancing pressure in the tank, and

' therefore, the speed of operation of the piston may be accuratelyr controlled, regardless of well loads. Manifestly, this arrangement makes pos sible a smoother and more uniform operation above the piston 26 may be expelled therefrom the desired quantity has been admitted 'to the l tank. the valve 93 is closed to shut off the flow or adjusted to permit the feedingof a fewdrops per minute, whereby any slippage of fluid past the piston is compensated.

The air within the tank 94,. which is exerted onthe upstroke of Vsaid piston. To prevent the formation of a vacuum within the upper end of the cylinder, an airi inlet valve |02 is connected in the pipe|00 so that air may be drawn into said cylinderpon the downstroke of the piston 26. fA suitable manual control valve |03 is mounted in the pipe '|0 intermediate the

tubes

81 and 92, while a similar valve |04 is located in advance of said tube 92. For bleeding off air or gas pressure which might accumulate within the elongate cap or housing 34, a small tube |05 establishes communication between said housing and the exhaust pipe 1|..` A hand valve |06 is connected in the tube so that the pressure within the housing may be bled into the pipe '1| immediately prior to the operation of the lifting mechanism and then closed during such opere- OIL i sure fluid to overcome or lift one-half of the In operation, a pressure fluid is introduced into the annular space 23 by means of the pipe 10 and 3| and. since the parts are in the position shown in Figure 1 andFigures 3 to 5, the fluid will flow through the cushioning slots 30 into the lower end of the cylinder 22. of this fluid acts against the underside of the piston 24 to move the same upwardly in its cylinder with the result that the

piston rods

48 and 25 secured to said piston, as well as the counterbalance piston 26 connected to the rod 25, are raised. The lifting of the piston 26 causes the sucker rods i2 and pump plunger to be moved upwardlyv also since they are secured thereto by the rod 28. Toward the end of the upstroke of the piston, flow through the opening of the valve 12 is restricted by the plunger16 so as to decelerate the speed of the movement of said piston.

However, upward movement of the piston 24 continues until the sleeve 6| vwhich is carried 4by the rod 48 strikes the underside of the lower internal ribs 48 of the valve member 38. As has been hereinbefore explained, this engagement causes the spring 62 to be compressed and the sleeve 6| to telescope the sleeve 59, whereby the flange 59a contacts the'lower end of said sleeve 6| to directly transmit the force of the fluid pressure exerted against the lower end of the piston 24 to the lower end of the valve member. When this pressure overcomes the pressure acting downwardly on the flange 39 as well as the frictional resistance of the spring-pressed ball 66, the valve member is moved away from the seat I2 to its upper or raised position (Figure 7), and such upward movement will be accelerated by the compression of the spring 62. Any fluid be@ tween the valve member and the seat 44 may bleed into the groove 45 and pipe 46 on the upward movement of said member due to the reduced diameter of the extreme upper end 41 of said member. With the valve` member in this position, its upper end will engage the seat 44 and communication between the annular space 23 and the upper end of the cylinder 22 is established. At the same time, the co-action of the camv collar 85 and the roller 83 of the rod 80 moves the plunger outwardly to substantially close the opening 15 of the valve 12 as shown in Figure 2, whereby a restricted flow of iluid enters The pressure the space 23 through the reduced opening of said valve and the tube 81. Thus, the end of the upstroke of the piston is cushioned.

The reduced flow of uid to the space 23 will enter the upper end of the cylinder 22 by means of the slots 43 and the enlarged bore 31 of the valve body, whereby ther pressure of` said fluid will be exerted against the upper surface as well as the underside of the piston 24. Since the effective cross-sectional area of the upper sur-` face of the piston is greater than the underside thereof, the pressure of the fluid acting against the underside will be nullied. Whenever the pressure of the fluid is suflicient to overcome the air pressure utilized as a counterbalance, the piston 24 will be forced to its lowered position. As the piston 24 moves downwardly, it is obvious that a downward movement will be im- (Fgure 10) and permit an increased flow to the' movement oi' the piston will ybe accelerated. However, the end of the downstroke of the piston will be cushioned by the co-action of the depending skirt 29 of said piston and the cushioningslots 30. i

The valve member 38 remains in its raised position until the sleeve 52 on the piston rod 48 engages the upper internal ribs of said member (Figure 7). When the sleeve strikes the Vribs and 'the piston rod continues its downward movement, the spring 55 confined within said sleeve is compressed, and the flange 54a moved into engagement with the lower end of the sleeve by the same telescoping the sleeve 54. Thus, the force of the fluid pressure acting downwardly on the piston 24 is applied directly to the upper end of the valve member to overcome the frictional resistance of the spring-pressed ball 66 and the pressure exerted against the lower end of said valve member, whereby the latter is again lowered so that its seating surface 40 will engage-the seat 42 and shut cfr ow through the slots 43 into the upper end of the cylinder 22. The pressure of the fluid will then be exerted solely against the lower surface of the piston 24 so as to again move the same upwardly, whereby the operation is repeated. It is noted that although the hereinbefore described hydraulic lifting mechanism A isfully reciprocating, that is, raised and lowered by a pressure fluid, the lsame only exhausts on the upstroke thereof,

whereby the valve mechanism is simplified. It is also pointed out that the lifting mechanism could be positioned within the bore of a well by disposing the various parts yin concentric conductors. y

In Figure'll. a modified form of control valve is shown and said valve may be mounted in the mechanism at the same point as has been hereinbefore described. The valve includes a valve body |33, similar to the valve body 33, which is connected by the coupling 35 to the housing 34 and has its depending collar |32 screw-threaded into the* upper end of the sleeve 20. An axial bore |36 extends vertically through the valve body and is provided with enlarged counterbores |34 and |31 at its upper and lower ends. A valve member |38, similar to the valve member 38, is

lslidable in the bore |36 and has its lower end the same diameter as the flange |40 of the collar |39, whereby said ange has a snug sliding fit within the enlarged portion ofthe bore and engages an annular valve seat |42 screw-threaded therein. To' establish communication between the annular space 23 and the lower counterbore |31 of the valve body, angular flow slots or openings |43 are formed in the upper peripheral portion of the collar |4l.

Anannular, upstanding ilange |35, of slightly less diameter than the upper counterbore |34 piston 24. Thus, the speed of the downward of the valve body, is preferably made integral with the external upper end of the valve member |38, whereby the annular space between the flange and said counterbore permits iluid pressure above said valve member to bleed into the groove 45 and pipe 46 in the same manner as the reduced upper end 41 offthe valve member I3. The iiange |35 is arranged to engage a valve seat |45 formed by a collar |44 which is screwthreaded into the lower end of the coupling 35. A ange |46, complementary to the flange |35, depends from the collar |44 and engages within said flange |35 when theV valve member is moved upwardly to its raised position. When the member 38 is in this position, the upper end of the iiange |35 will engage the valve seat |45 and the upper end of said member will be engaged by the flange |46 to shut off communication between the groove 45 and the bore of the member. It is pointed out that the ange- |40 of the collar |39, which has a snug sliding iit within the bore of the collar |4|, does not move out of engagement with said bore until the ange 35 of the valve member has engaged the flange |46 to close the bore of said member. Thus, .no fluid is admitted into the upper end of the cylinder 22 through thel annular space 23, slots` |43 and counterbore |31 until after the exhaust pipe and groove have been shut off, whereby the occurrence of a balanced condition is obviated.`

vFor raising the valve member |38, a short sleeve |41 is slidably mounted on the piston rod 48 and is confined between the collars 60 and B4 which are positioned in close proximity to each other. An external, annular flange |48, of substantially the same diameter as the bore of the collar |4I, upper portion of the sleeve for engaging the collar |39 of the valve member. of the ange |48 is suchwthat when the'same is in engagement with the valve member, the bore of said member is closed to prevent the passage of fluid pressure thereinto. The upward .movement of the valve member |38 by the sleeve |41 is substantially the same as the upward movement of the valve member 38 by the

telescoping sleeves

59 and 6|, hereinbefore described in the first form, with the exception that there is no frictional resistance to such 4movement nor any spring for imparting a snap action to said valve member. However, the telescoping Isleeves 52 and 54 and coiled spring 55 are employed to move the valve member |38 from its upper to its lower` position in exactly the same manner as in the first form. The internal, radial, guide ribs 49 are formed Within the upper end o f the valve member and within the collar |39 which is screwthreaded into the lower end of said member.

During the upward movement of the piston 24, the seating surface of the flange |40 of the valve member will be held in engagement withthe valve seat |42 :by the iiuid pressure exerted against the upper end of said member. Due to the provision of the iiange |35, the effective cross-sectional area of the upper end of the valve member is greater than the small portion of the lower end of said member exposed to When the valve member is in its raised position with the upper end of the flange |35 engaging the valve seat |45 and the lower end of the flange |48 engaging the upper end of said member, the eiTective cross-sectional area of the lower end of the member will be greater than that of its upper end. Thus, the fluid pressure maintains the member |38 in its raised and lowered positions and in snug engagement with the valve seats |42 and |45 until the position of said member is changed by the reciprocation of the piston 24 and its rod 48.

If desired, the valve member |38 may be raised by the

telescoping sleeves

59 and 6| and the coiled is preferably made integral with the The diameter the iiuid pressure.,

`stroke of said piston in' spring 32 in place oi' the short sleeve |41 without aii'ecting' the operation 0f said valve member. It is noted that a plurality of anisms may be connected to a single source of uid pressure instead of providing a separate source for each mechanism. `As shown in Figure l2, lifting mechanisms A and B may have their fluid inlet pipes 10 communicating with a suitable pump |07 by means of a line |08. The pump is driven by a suitable engine |09 and is supplied with liuid from a reservoir H0. The fluid exhausted from the mechanisms through the pipes 1| is conducted to the reservoir by a line Manual control valves for controlling the flow of uid through the lines may be provided at various convenient points.

In Figures 13 and 14, a slightly modified form of lifting mechanism is shown and includes the cylinder 20 within which the cylinder 22 is supported by the reduced, upstanding collar 2| of the stuiiing box I9. A hollow piston |24, similar to the piston 24, is slidably disposed within the cylinder 22 and is connected to the counterbalancing piston 26 by a depending, tubular piston rod |25 which is screw-threaded into the lower end of the axial bore |26 of the piston, -whereby the bore of the rodcommunicates with the bore of said piston. The bore |25 also communicates with the cylinder 22 above the piston by means of a plurality of upwardly and outwardly inclined, radial ports |21. The lower'end of the piston is reduced in diameter as shown at; |29 and is arranged to co-act with the cushioningslots 30 of the cylinder 22 to absorb the shock of the downa the same manner as the skirt 29 0f the piston 24.

A valve body ||2, similar to the valve body 33, has its reduced, depending collar ||31 screwthreaded into the upper end of the sleeve 20 andV is provided with an axial bore I4, the intermediate portion of which is reduced to forma counter-v bore |5. A tubular valve member H5, similar to the valve member 38, is slidable in the counterbore I5 and has a similar radial flange or 'shoulder ||1 formed on its lexterior adjacent its lower end. To provide an amplified seating surface, the underside of the iiange is bevelled, as shown at IIB, complementary t0 the valve seat 4:2 of the collar 4| which is screw-threaded into the upper end of the cylinder 22. A removable sleeve I9 is interposed between the valve member I6 and the, counterbore ||5, whereby undue Wear of said counterbore is prevented. The angular slots 43 formed in the peripheral upper portion of the (ill collar42 establish communication between the lower end of the bore ||4 of the valve body and the annular space 23.

The upper end of the valve body ||2 is connected by a coupling |20, similar to the coupling 35, to the lower end of a short cap or housing l2 A collar |22, having an annular groove |23 formed in its under-surface, is screw-threaded into the lower end of the coupling |20 and depends within the upper end of the bore |4 of the valve body, providesa valve seat which is adapted to be` engaged by the upper end of the valve member ||6 as shown in Figure 14. The inner peripheral lower end portin of the collar |22 terminates a short distance above the lower end of said collar to form an annular, internal flange |28'. Since the external diameter of the flange |28' is` slightly less than the` internal diameter of the bore of the valve member H6, an annular space or clearance is provided therebetween to permit the escape of fluid trapped behydraulic lifting mechbe displaced into the pipe ine 8 tween said member and the collar |22 upon the upward movement of the member. Obviously, the fluid within the upper end of the bore ||4 may 46 which communicates therewith upon the upstroke of thevalve member.

It is manifest that this valve member controls the admittance to and exhaust of fluid from the cylinder in the same manneras the valve members 38 and |38 and that the pressure of this fluid actuates the piston |24 in the same maner as the piston 24. A piston rod |30, of less diameter than the bore |26 of the piston, extends axially through said bore, the tubular rod |25, the valve member IIB-and through the housing |2I. For guiding the piston rod |30 axially through the valve member, a plurality of internal, radial ribs |3| are provided at the upper end of said valve member. The piston rod is slidably connected to the piston by means of a flanged bushing |49 which is screw-threaded into the upper end of the bore of said piston and a nut |50 carried by the lower end of said rod. Since the nut |50 is of a diameter greater than that of the bore of the bushing |49, through which the piston rod extends, it

is obvious that said rod may not be disconnected.

from the piston without removing said nut or bushing. A sleeve having an external, radial shoulder or iiange |52 formed on its upper end, is screw-threaded into the upper end 'of the anged bushing |49 and surrounds the piston rod |30 which is slidable through its bore. The upper end of the piston rod projects through a stuffing box |53 screw-threaded into the top of the hous- |2| and this stuffing box co-acts with the sleeve |5| and ribs |3| of the valve member to maintain said rod axially disposed.

For raising the valve member, a short sleeve |54 is slidably mounted on the sleeve v|5| between the flange |52 of said sleeveand a collar v|55 positioned adjacent theupper end thereof. Th sleeve is very similar to the sleeve |41 (Figure 11) and has asimilar external, annular4 ange |56 made integral with its upper end for engaging the lower end of the valve member. The diameter of the ange |56 is greater than the diameter of the bore of the valve member, whereby said bore is closed to prevent the passage of pressure fluid thereinto when said flangev is in engagement withthe lower end of said merrber. rIfhe upward movement of the valve member ||6 by the sleeve |54 is exactly the same' as the upward movement of the valve member. |38 by the sleeve |41, since the sleeve |5| which carries said sleeve |54 is connected to andis movable with the piston |24. The valve member I I6 is moved from its upper to its lower position by the

telescoping sleeves

52 and 54 and coiled spring 55 in substantially th-e same manner as the valve members 38 and |38, as has been hereinbefore described, with the exception that the lower end of the bushing |49 must engage the nut |50 carried by the piston rod |30 before said sleeves and spring will effect the downward movement of said valve member ||6. Thus, the desired downward movement of the piston |24 relative to the valve member and piston rod is permitted, with the result that said rod and the housing |2| may be of materially less length than the piston rod 48 and housing 34 of the first form. l

In order to4 prevent the formation of a fluid seal between the lower end of the bushing |49 and the upper surface of the nut |50 when the same are in engagement, a `plurality of radial grooves or recesses |51 are formed in the lower end of said bushing, thereby eliminating the posbalancing the lifting mechanism,

assen?? of said piston. Due to the provision of the ports |21 in the piston, a portion of the fluid within the bore of the rod |25 and the bore of said piston above the nut |50 will be discharged`into the cylinder 22 above the piston by the relative upward movement of said nut so as to prevent resistance to such relative movement. However, the chief function of theports |21 is to by-passthe fluid displaced from the rod and piston bores to the cylinder upon the upward movement of the piston and rod relative to the nut and piston rod |30. It is pointed out that the operation of the valve member H5 would not be materially affected if the sam-e was actuated by the mechanisms of the valve members 38 and |38 instead of the particular mechanism which has been hereinbefore described.' It is also manifest that the valve members 38 and |38, if desired, may be actuated by the mechanism of the valve member IIB.

In many instances, it may be d-esirable to utilize the gas or other pressure within the well casing to counterbalance the lifting mechanism in place of the air pressure as shown in Figure 15. In this event, a small tank |58 is substituted for the tank 94 and has its upper end connected by a pipe |59 to the flow outlet |60 of a casing head |6| mounted on the upper end of the well casing the interiors of the tank |58 and casing I0, whereby the gas pressure within said casing may be exerted upon the liquid within said tank in exactly the same manner as the air pressure. For controlling the pressure of thegas delivered to the tank, a suitablepop-oi valve |62 is mounted in the pipe |53. A manual control valve |63 is also connected in the pipe between the pop-oit valve |62 and the flow outlet-|60. In some wells, the well fluid will be standing within the casing in relatively close proximity to the surface, with the result that there will be an accumulation of gas within the upper portion of said casing above the fluid level. Usually, this. gas will be under a pressure suflicient to be utilized for counteralthough such pressure is insufficient to force the well uid up the tubing. In the event no pressure-is present within the casing, a packer (not shown) may be ins-erted within the casing so as to seal off the annular space between the tubing andrsaid casing and form an annular chamber thereabove. An auxiliary pressure may then be introduced into the annular chamber or the vupper portion of the casing through the flow outlet |60 of the casing head IBI, whereby such pressure may be employed to counterbalance the lifting mechanism.

As shown in Figure 16, the tank |58 may be eliminated entirely by connecting the pipe |59 directly to the pipe 95. In this instance, the 1ubricating liquid would be dispensed with and the pressure of the gas Wouldbe exerted directly against the underside of the counterbalancing piston 26.

The foregoing description of thek invention is explanatory thereof and various changes in the wlthinthe scope of the appended'claims, without departing from the spirit of the invention.

What we claim and desire tosecure by Letters Patent is:

-1. A hydraulic lifting mechanism" including, a

cylinder, a piston arranged to reciprocate within the cylinder having its lower end exposed to a pressure fluid for raising the same, an annular sleeve valveforming a continuation of said cylinder and adapted to expose the upper end of the piston to the pressure fluid upon the completion of its upstroke, the upper end of said piston having a greater cross-sectional area than the lower end thereof, whereby the pressure of said fluid will force the piston downwardly, and means carried by said piston and movable through said valve for actuating the valve to control the movement of the piston.

2. A hydraulic lifting mechanism including, a cylinder, a pressure responsive member movable in the cylinder having its lower end exposed to a pressure fluid for raising the same, means for admitting the fluid to the upper end of the member upon the completion of itsv upstroke so as to force the same downwardly, means for controlling the flow of fluid to the cylinder.' means for lower end of said cylinder to cushion the down- `actuating the controlling means to restrict the flow of uid therethrough as the member approaches the upper end of its stroke to cushion the upstroke thereof, and means for restricting the discharge of fluid from the lower end of said cylinder to cushion'the downstroke of said member.

3. A hydraulic lifting mechanism including, a cylinder, a pressure responsive member movable in the cylinder having its lower end exposed to a pressure fluid for raising the same, means for directing a portion of the uid to the: upper end of the member upon the completion of its upstroke, the uppervend of said member having a greater cross-sectional area than the lower end thereof, whereby the pressure of said fluid will force the member downwardly, means for restricting the flow of the fluid to the cylinder as said member approaches 'the upper end of its stroke to cushion the upstroke thereof, and means for restricting the discharge of iiuid from the stroke of the member.

RALPH C. FARLEY. J. W. GILLESPIE.