US2168711A - Fluid actuated power apparatus - Google Patents

Description

Aug. 8, 1939. c, KYLE 2,168,711

FLUID ACTUATED POWER APPARATUS I Filed Feb. 1, 1938 4 Sheets-Sheet 1 INVENTOR 54/?1/62 6170f KYL E BY V 7 ZTTORNY Aug. 8, 1939.

5. C. KYLE FLUID ACTUATED POWER APPARATUS Filed Feb. 1, 1938 Z7ZZ6. Z.

' INVENTOR l/W/ZL 60 015 A414! I 4 Sheets-Sheet 2 g- 3, 1939- s. c. KYLE I 2,168,711

FLUID ACTUATED POWER APPARATUS Filed Feb. 1, 1938 4 Sheets-Sheet 3 as VENTOR BY %TTORNEY Patented Aug. 8, 1939 UNITED STATES PATENT OFFIQE Samuel Clyde Kyle, San Francisco, Calif., assignor to Mary G. Mulvany Application February 1, 1938, Serial No. 188,092

Claims.

My invention relates to fluid actuated power apparatus and has particular reference to a power device especially adapted for the operation of reciprocating pumps for oil or similar liquids. In the pumping of liquids from a well, such as pumping oil from an oil well, it is the common practice to employ a pump located near the bottom of the well having a reciprocating barrel or plunger therefor adapted to be reciprocated by power apparatus located on the ground surface, the connection between the reciprocating apparatus and the movable part of the pump being made through a string of sucker rods.

As will be understood by those skilled in the art, the length of string of sucker rods is such that considerable stress occurs in the sucker rods upon each reciprocation of the machinery so that the effective reciprocating stroke produced at the pump is considerably shorter than the reciprocating stroke of the machinery located on the ground surface. Hence it is desirable to employ reciprocating power machinery at the ground surface which may produce a great stroke length.

Also considerable 'difliculty is encountered in the removal of the power device and its connections to the sucker rods from a position immediately over the well whenever the sucker rods, pump tubing or other devices are to be removed from the well.

It is therefore an object of my invention to provide a reciprocating apparatus which may be readily located at the ground surface and which is adapted to produce a relatively great length of stroke upon sucker rods or similar devices connected thereto.

Another object of my invention is to provide an hydraulically operated power mechanism in which a cylinder and piston is employed for raising and lowering the sucker rods and in which the cylinder mechanism may be manufactured in sections to permit any desired length of stroke of the piston to be employed.

Another object of my invention is to provide an hydraulic power mechanism of the character set forth in the preceding paragraph wherein certain of the cylinder sections are adapted to receive valve and valve operating structures thereon while intermediate pump sections may be substantial duplicates of each other, permitting the carrying in stock of intermediate pump sections to permit the ready assembly of a pump for any desired length of stroke.

Another object of my invention is to provide a pump operating mechanism of the character set forth wherein the valves employed for reversing the movements of the piston may be operated by air compressed by the normal reciprocating movements of the piston within its operating cylinder.

Another object of my invention is to provide a reciprocating mechanism for a pump which may be hydraulically operated and in which the reciprocating mechanism acts as a compressor for air to be employed for actuation of the valves of the mechanism.

Another object of my invention is to provide a pump operating mechanism comprising a cylinder and piston, the piston adapted to be raised in the cylinder by fluid pumped into the cylinder below the piston while gravity is employed for the down stroke of the piston, with means for decelerating the downward movement of the piston as it approaches the lower end of its stroke.

Another object of my invention is to provide a method of actuating control valves for an hydraulic pump operating mechanism wherein the control valves are actuated by compressed air and wherein the upward stroke of the piston compresses a quantity of air in excess of that required to actuate the valves.

Another object of my invention is to provide a pump operating mechanism of the character described which may be mounted upon a base at the ground surface readily adapted to be moved into a position of alignment with the sucker rods or to be swung away from such position to permit ready access to the sucker rods and pump mechanism in the well.

Other objects and features of my invention will be apparent from a study of the following specifications, read in connection with the accompanying drawings, wherein,

Fig. l is a side elevational View of a pump operating mechanism constructed in accordance with my invention, illustrating the manner in which the mechanism may be mounted upon a swivel base so as to permit swinging of the pump operating mechanism from a position of alignment with the well hole to a position out of the path of access to the sucker rods and other mechanism contained within the well;

Fig. 2 is a vertical elevational view, partly in section, of the cylinder, piston and valve operating mechanism illustrated in Fig. 1 and illustrating the piston in its uppermost position with the valves in their positions necessary to start the down stroke of the piston;

Fig. 3 is a horizontal sectional view taken along line III-III of Fig. 2;

Fig. 4 is a vertical sectional view similar to Fig. 2 but illustrating the piston in its lowermost position and the valves in their positions to start the up stroke of the piston;

Fig. 5 is a vertical sectional view of the upper part of the piston and cylinder mechanism and illustrating a modified form of air compressor and valves which may be employed in the practice of my invention;

Fig. 6 is a detail horizontal sectional view similar to Fig. 3 and illustrating a modified hydraulic valve construction which may be employed in the practice of my invention;

Fig. '7 is a horizontal sectional view taken through the valve structure shown in Fig. 6;

Fig. 8 is a vertical elevational View, partly in section, similar to Fig. 2, illustrating a modified form of hydraulic control valve which may be employed in the practice of my invention, the piston being illustrated in its uppermost position and the control valve in the position ready for the start of the down stroke; and

Fig. 9 is a detail view of the control valve shown in Fig. 8 and illustrating the position of this valve when the piston is in its lowermost position and ready to start its up stroke.

Referring to the drawings, I have illustrated in Fig. 1 an assembly of my pump operating mechanism upon a derrick floor, the assembly comprising a suitable supporting post or standard I, the upper end of which is provided with a reduced shank 2 constituting a pivotal mounting for a base plate 3. The base plate 3 is preferably rectangular in plan having a pair of arms 4 and 5, one adapted to extend forwardly over the upper end of a casing head 6 extending into the well, the casing head including an oil flow pipe I through which oil pumped from the well may pass outwardly to an oil line 8, sucker rods extending downwardly into the well through the flow pipe I, the upper end of the sucker rods terminating in a polished rod 9 to which my pumping mechanism may be attached.

The arm 5 of the base plate 3 constitutes a mounting for my cylinder and piston power mechanism assembly which preferably comprises a plurality of cylinder sections Illa, IOband Iilc assembled one upon the other, the lower section Illa preferably including the valve mechanism by which fluid power means may be supplied to the interior of the cylinder and controlled, while the section IBb which is disposed immediately above section Illa preferably includes operating mechanism by which the hydraulic control vlave may be actuated. The sections I disposed above the section Ifib may be duplicates of each other, permitting the employment of as many of these sections as is desired to produce a cylinder of sufficient length to permit any desired stroke of the piston I2 which operates therein, each of the cylinder sections Iila, Ifib, and IE0 having a central bore II constituting the interior walls of the cylinder through which the piston i2 operates.

As will be observed by those skilled in this art, the construction of the cylinder from an assembly of substantially duplicate parts permits the carrying in stock of these parts which may be readily selected and assembled together to construct a cylinder of any desired length while constructing the cylinder of interchangeable sectional members permits the ready replacement of any of the cylinder sections in making repairs without requiring the supplying of an entire new cylinder.

The lower end of the cylinder section Ilia is adapted to rest upon a cylinder head I3, the cylinder head and lower end of the cylinder section Illa being chamfered as indicated at I4 to insure accurate concentric alignment between these members, suitable packing (not shown) being interposed between the cylinder head I3 and the cylinder section Illa if desired. The cylinder head I3 is provided with an opening I concentric with the bore II and preferably of a diameter slightly in excess of the bore II adapted to be closed by a plug I6 threaded as indicated at I! into the cylinder head. The plug I6 has a central bore I8 extending therethrough adapted to receive the piston rod I9, the piston rod I9 being preferably an extension of the polished rod 9.

As is illustrated particularly in Figs. 2, 3 and 4, the piston rod I9 may be constructed of a section of sucker rod constructed in the usual manner with swedged out head 20 adapted to be received in a socket 2| formed in the lower face of the piston I2 and held therein by means of a suitable threaded bushing 22 engaging the lower shoulder 23 of the head 20, a lock nut 24 being provided upon the bushing 22 to lock the same firmly in place to hold the piston tightly upon the piston rod I9.

The plug It may be provided with a suitable bearing bushing 25 and a packing gland 26 to provide a slide bearing through which the piston rod I9 may readily operate. By referring to Figs. 1, 2 and 3, it will be observed that the cylinder head I3 is provided with a a slightly downwardly depending boss 27 so that when the plug I5 is assembled in place in the cylinder head I3 the boss 21 and plug I6 will project downwardly below the main portion of the main face of the cylinder head I3. The arm 5 of the base plate 3 may be provided with a circular opening 28 into which the boss and plug may project, the opening 28 constituting a centering and aligning means fixing the assembled position of the cylinder section Ifla with respect to the arm 5.

The cylinder section IIlb similarly comprises a cylindrical member having a bore IIb extending longitudinally therethrough, through which the piston operates, the section Iflb having its lower end chamfered as indicated at 29 to seat upon the upper end of the cylinder section we to hold the bore I Ib in alignment with the bore II of the section Illa, the cylinder sections Illa and IIlb having laterally projecting portions thereon adapted to constitute the housing for control valve mechanism by which fluid employed as the power means may be introduced into and exhausted from the bore III Ib to cause the piston to move upwardly and downwardly within the bore. The section IEIa preferably constitutes the housing for a control valve 30 as by providing a laterally extending portion 3I on the section Ifla having a longitudinal valve chamber bore 32 formed therein in which the valve 30 is adapted to reciprocate longitudinally of the housing section Illa. The valve 30 is indicated in the form of the device shown in Figs. 1, 2, 3 and 4 as of the spool type including a pair of reduced diameter sections 33 and 34 defined between end enlargements 35 and 36 and an intermediate enlargement or partition 37. The lower portion of the valve chamber 32 is provided with an exhaust port 38 to which a suitable pipe 39 is connected and through which oil or other fluid medium employed as a source of power may be passed to a fluid tank 40 (see Fig. l). The lower portion of the valve chamber-32 is likewise provided with a port 4! which communicates with the cylinder bore II, the point of communication between the valve chamber 32 and the bore I I being preferably made through a longitudinally tapering recess 42 extending laterally from the bore II, as indicated in Figs. 2 and 3.

A fluid inlet pipe 43 is illustrated as communicating with a fluid inlet port 44 in the valve chamber 32 while an auxiliary exhaust or by-pass port 45 is illustrated as being connected to a pipe 39a which couples with the tank 40.

While it will be understood by those skilled in the art that any source of fluid power may be employed for reciprocating the piston within the cylinder assembly, I prefer to employ oil as the fluid medium and pump such fluid from the tank 40 by means of a small liquid pump 46 coupled to the tank it, the exhaust of the pump 46 being connected directly to the fluid inlet pipe 33, a pressure chamber 4? being provided if desired for the purpose of producing a substantially uniform flow of fluid through the pipe 43.

By referring particularly to Fig. 4, it will be observed that when the piston I2 is in its lowermost position and is ready to start its up stroke, the valve 343 should be in the position shown in Fig. 4 to couple the fluid inlet pipe 43 with the inlet port 4! allowing fluid to flow into the space below the piston 12, it being understood that the recess 42 is so disposed in the cylinder section Illa that its lower end 42a extends below the lowermost portion of the piston [2 when the piston is in its lowermost position, while the height of the recess 42 is such that the upper end of the recess will at this time be closed oif from communication with the bore H by the upwardly extending skirt l2a of the piston l2. Thus the incoming fluid through the pipe 43 will drive the piston upwardly within the cylinder assembly, producing an up stroke of the piston. It will also be observed that during the up stroke of the piston the exhaust ports 38 and 35 are closed so that all of the liquidpumped by the pump 66 will pass into the bore H to produce the up stroke of the piston.

Now by referring particularly to Fig. 2, it will be noted that when the piston is in its uppermost position as shown therein, the reversal of the valve 30 will interconnect the exhaust pipe 39 with the port 4 l, allowing the oil which has previously been pumped into the bore H to now exhaust therefrom while at the same time the new position of the valve 36 will intercommunicate the fluid inlet pipe 43 with the auxiliary or bypass pipe 39a, permitting the pump it to continuously operate and to circulate oil through the auxiliary exhaust pipe 39a back to the tank. As will be understood by those skilled in the art, the weight of the sucker rods and the weight of the column of fluid being lifted by the sucker rods and their associated pump will cause the piston ii to descend in the cylinder assembly by gravity, forcing the oil in the cylinder assembly out through the exhaust pipe 39 and back to the oil tank 40. The tapered recess 42 constitutes an effective deceleration device for slowing down the piston as it approaches its lowermost position within the cylinder assembly. It will be noted that when the piston is above the recess 43 the entire recess constitutes an opening through which fluid may readily be exhausted from below the piston while as the piston approaches its lowermost position it will gradually close off the recess 42, diminishing the effective area through which the fluid below the piston is exhausted from the cylinder assembly until when the piston arrives at its lowermost or final position, as indicated in Fig. 4, a relatively smallarea opening is provided between the piston and the recess 42. By properly designing the effective area of the recess 42, any desired deceleration factor may be provided.

As will be understood by those skilled in the art, the valve 30 should be moved between its two positions by substantially snap action in order to prevent the possibility of hydraulically locking the system and for this purpose I prefer to employ air under compression for the purpose of shifting the valve 38 as by providing an extension 48 on the valve 30, which extension 48 projects upwardly into an air chamber 49 formed in a laterally extending housing 50 constituting a part of the cylinder section Mb. The chamber t9 constitutes in effect a cylinder within which operates a double-ended piston 5i secured as indicated at 52 to the upper end of the extension 48. ihus by introducing air under pressure either at the top end of the chamber 49 through an inlet port indicated at 53 or at the lower end of the chamber 50 through an inlet indicated at 54, the piston 5| may be raised or lowered to shift the valve 30 between its two operating positions. By arranging to introduce the air into the upper end or lower end of the chamber 49, it will be apparent that the action of the air will be tosnap the valve 36 to either of its operating positions.

I also prefer to employ the up stroke of the main piston I 2 as a means for compressing air for the operation of the valve 30 and, as is illustrated in Figs. 1, 2 and 3, this may be readily accomplished by providing a cylinder head 55 at the upper end of the uppermost cylinder section 1 c, the cylinder head 55 having a port 56 formed therein and communicating with the upper end of the cylinder assembly in such manner that the up stroke of the piston l2 will force air above the piston through the port 56 and through a pipe into an air pressure tank 58, a suitable check valve 59 being interposed in the pipe 5! to prevent the compressed air from the tank 58 from passing back into the cylinder assembly.

The upper cylinder head 55 is also preferably provided with an inlet port 6!) in which may be located a poppet valve Bl normally held in closed position by means of a spring 62 so that as the piston i2 is moved downwardly air will be drawn in through the port 66 past the poppet valve Bi but upon the up stroke of the piston l2 the valve 6i will close, insuring that the air which had previously been drawn in will now be forced out under compression through the outlet port 5%.

I also employ the up and down strokes of the main piston l2 as a means for controlling the air compressed by the piston to supply such air alternately to the upper and lower ends of the valve operating chamber or cylinder 49 as by providing an upwardlyextending boss 53 on the cylinder head 55, provided with a bore 64 which constitutes an operating chamber in which a slide valve 65 may reciprocate. The slide valve 95 is preferably of the spool type, somewhat similar in construction to the valve 30 having a plurality of reduced sections 65, E? and 68 separated from each other by enlarged portions of the valve member 65, the reduced sections constituting means for intercommunicating an air inlet port 59 and a pair of air outlet ports and M.

It will thus be apparent that when the air con trol valve 65 is in the position shown in Fig. 2, that is, in its uppermost position, air introduced into the inlet port 69 through a pipe :72 extending from the air tank 5% will pass into the valve cylinder 6t and outwardly through the outlet port '40 to pass through a pipe 13 to the lower end of the valve operating chamber 49, thus causing the valve operating piston 5! to be raised, shift-- ing the liquid control valve 39 to its uppermost position as shown in Fig. 2.

Similarly when the air control valve 65 is in its lowermost position as shown in Fig. 4, the air inlet pipe 12 will supply air from the tank 58 into the inlet port 69 and thence through outlet port II to a pipe I4 which communicates with the port 53 in the upper end of the valve operating cylinder or chamber 49 to cause the valve operating piston 5| to be depressed, shifting the valve 30 to its lowermost position as shown in Fig. 4. It will be noted that when the air control valve 65 is in either of its positions, as illustrated in Figs. 2 and 4, air exhausted from the valve operating cylinder 49 as the piston 5| moves to its new position is permitted to feed back through the pipes -I3 or I4, respectively, and through their ports I0 and II, respectively, which will be in communication with exhaust openings 15 or I6, respectively, dependent upon the position of the air control valve 65.

In order to insure that the control valve 65 will remain in either of its two operating positions without creeping, I prefer to provide a latch mechanism comprising a pair of grooves TI and I8 on the valve body 65, into either of which grooves may be received the tapered end of a latch pin 19 slidable in a laterally extending boss on the housing for the valve body 65, a spring 8| adjustably compressed against the pin I9 by means of an adjusting screw 82 threaded into the end of the boss 80, normally urging the pin 19 into the grooves 11 or I8. When the air operating valve 65 is in its uppermost position, the pin 19 will be received in the lowermost groove I8 while when the valve 65 is in its lowermost position, as shown in Fig. 4, the pin I9 will be received in the groove TI.

In the form of the device illustrated in Figs. 1 through 4, I have employed the piston I2 as the means for shifting the position of the air operating valve 65 between its two operating positions as by extending a stem 83 downwardly from the valve body 65 into the open end of the cylinder within which the piston I2 operates, a perforated plate 84 being secured upon the lower end of the stem 83 as by means of a nut 85, the plate 84 having a diameter just slightly less than the diameter of the cylinder within which piston I2 operates so that upon the up stroke of the piston I2 the upper end of the piston skirt will engage the plate 84 and lift the same, lifting the air control valve 65 to its uppermost position.

By referring particularly to Figs. 1 and 2, it will be noted that when the piston I2 arrives in its uppermost position and is ready to start the down stroke, the lifting of the air control valve 65 will direct air from the tank 58 into the valve operating cylinder 49 in such manner as to raise the liquid control valve 38, setting this liquid control valve in the proper position to permit the down stroke of the piston under the influence of gravity, while when the piston arrives in its lowermost position, as indicated in Fig. 4, the chain 86 interconnecting an eyelet 81 fixed upon the piston I2 and an eyelet 88 secured to or forming a part of the nut 05 will be drawn taut, the length of the chain 89 being selected such that during the last few inches of downward movement of the piston I2 it will draw the air control valve 65 downwardly to the position shown in Fig. 4, thus supplying air from the tank 58 to the upper end of the valve cylinder 49 and shifting the position of the valve 30 to its lowermost position, for supplying liquid from the pump necessary to produce the next up stroke of the piston I2.

It will thus be apparent that I have provided a fluid actuated power device for reciprocating pump rods and the like, in which the piston connected to the pump rods or sucker rods will be raised by liquid pressure, the up stroke of the piston constituting an air pump which supplies air under pressure for operating the control valve for the liquid while at the same time the piston itself mechanically operates an air control valve for supplying air to the liquid control valve to cause this valve to be snapped from one of its positions to the other.

It will be obvious that the quantity of air which is compressed upon each up stroke of the piston will be far in excess of that required to shift the liquid control valve 30 between its two positions so that there is always an excess of air under pressure in the tank 58, a suitable pressure relief valve 89 being arranged upon the tank 58 or in the pressure line at any suitable point to control the maximum pressure which will be stored in the tank 58.

In Fig. 5 I have illustrated a slightly modified form of air control valve and compressor which may be readily substituted for the air control valve and air compressing mechanism illustrated in Figs. 1 through 4. In this form of the device a piston or collar 90 is mounted upon the lower end of a stem 9I in much the same manner as the perforated plate 84 was moutned upon the stem 83 as shown in Figs. 2 and 4, the piston 90 being secured in place upon the stern 9I as by means of a suitable lock nut 92 having an eyelet 93 formed thereon to receive the chain 86.

Mounted upon the upper end of the top cylinder section I00 is a cage, 94, an air screen or cleaner 95 being interposed between the cage 94 and the open end of the cylinder section I 00. The cage 94 bears upon its upper end a stufiing box 96, through which the stem 90 operates and passes into an air compressor cylinder 91, within which cylinder reciprocates an elongated piston 98. The piston 98 is rigidly secured upon the stem 90 as by means of a nut 99. The cylinder 91 is provided with a pair of ports I00 and Ifil which are connected, respectively, to the pipes 14 and I3 which, as is illustrated in Fig. l, are coupled to the valve operating cylinder 49. An air passage I02 is provided in the piston 98 extending from its lower face to a point spaced below the upper face of the piston 98, which air passage is provided with two laterally extending ports I83 and I04 communicating therewith so that when the piston 98 is in its lowermost position, as shown in Fig. 5, the port I03 will communicate with the pipe 14. Similarly the opposite side of the piston 98 is provided with an air pasasgc I05 having ports I06 and I0! communicating therewith. The spacing of the ports I03 and I00 and the ports I06 and I0! along the length of the piston 98 is such that when the piston 98 is in its lowermost position, as shown in Fig. 5, representing the condition when the main piston I2 is in its lowermost position, and is ready to start its up stroke, the port I03 in the piston 98 will be aligned with the port I00, that is, in communication with the pipe 14.

As the piston 98 was pulled down by the chain 86, air below the piston 98 was compressed so that when the ports I03 and I 00 are aligned with each other this compressed air escapes through the pipe 14 to the uppermost side of the liquid control valve piston 5 I, shifting the liquid control valve 30 to the position shown in Fig. 4, preparing for the supply of liquid to the piston I2 to start its up stroke. At the same time that the port I93 is aligned with the port I00, it will be noted that the port I06 is aligned with the port IOI communicating with the pipe 13 so that air which is exhausted from the lowermost side of the liquid valve operating piston 5| will escape through pipe 13, ports lili, H16 and thence through the passage I115 in the piston 98 to the uppermost side of the piston 98. It will be observed from an inspection of Fig. 5 that an opening N38 is provided in the walls of the cylinder 91 which will be exposed when the piston 98 is in its lowermost position so that the air which is exhausted through the pipe I3 will be permitted to escape to the atmos phere.

Now when the main piston l2 upon its up stroke approaches its uppermost position the skirt I20, of the piston I2 will engage the disc iii and elevate the same, raising the air compressor piston 98. The initial upward movement of the piston 88 will close off openings I08, converting the upper portion of the cylinder 91 into a compression chamber so that further upward movement of the piston 98 by the continued upward movement of the main piston I 2 will compress the air in this upper chamber until when the piston 98 arrives in its uppermost position its port If]? is aligned with port IHI, at which time the air which has been compressed above the piston 98 will escape through pipe 13 to the lowermost side of the liquid valve operating piston 5i, causing this piston to be lifted to its uppermost position and arranging the valve 39 in the position shown in Fig. 2 ready for the start of the down stroke. At the same time it will be noted that an opening H19 in the wall of the cylinder 91 will be exposed below the lower end of the piston Q6 so that air which is exhausted from the upper side of the ;;valve operating piston 5! will exhaust through pipe 74, port Iill'l (now aligned with port its) and thence through the passage IO'I to the lowermost side of the piston 98 and thence outwardly through the exposed opening its to the atmosphere.

It will be understood by those skilled in the art that the volume of air compressed upon each stroke of the piston 98 should be in excess of the volume of air required to move the valve operating piston SI from one of its positions to the iIIl being offset from the axial center of the,

piston 98 so as to prevent rotation of the piston 98 about its axial center.

It will be understood by those skilled in the art that other types of liquid control valves may be substituted for the liquid control valve (ill; for example, a valve of the type illustrated in Figs. 6 and 7 may be readily substituted for the valve 38. In Figs. 6' and '7 I have illustrated a rotary valve 6 I2 which comprises a valve housing I it having a central bore H 5 formed therein and into which extends a tapered valve plug H5 having a pair of arcuate passages H6 and Ill formed in the side walls thereof to intercommunicate with ports arranged in the housing H3. The housing H3 is adapted to have secured thereto the three pipes 43, 39 and 3a extending from the pump 46 and to the oil tank 48, respectively. Thus when the valve plug H5 is in the position shown in Fig. 7, oil which is supplied from the pump '46 through the pipe 43 will pass through a port H8 in the housing H3 and thence through a liquid passage I I9 into valve plug I I5 and through a port [29 which communicates with the recess 42 in the cylinder section Iiia to cause the main piston 12 to move upwardly within its cylinder assembly. Now when the piston I2 arrives in its uppermost position, shifting of the ping valve 5 through substantially 45 will align the liquid passage I ll with the port I I8 and with a port IZI communicating with the by-pass pipe 39a so that liquid pumped in by the pump 36 will be circulated through the pipe 39a back to the tank 46. At the same time the liquid passage H6 in the plug valve H5 will be aligned with a port I22 communicating with the exhaust pipe 39 and also with the port I23 so that oil from below the main piston #2 will be permitted to exhaust from the cylinder assembly and through the pipe 39 back to the tank 49.

The operating mechanism for moving the plug Valve H5 from the position shown in Fig. '7 to its reverse position is illustrated particularly in Fig. 6 as comprising a crank arm I23 secured to the plug valve I l5, the outer end of the crank arm I23 having a ball i2 2 thereon adapted to be received in a recess I25 in a bar I26 which interconnects a pa r of pistons I2? (only one of which is shown in Fig. 5). The pistons IZI are mounted for reciprocation within a valve operating cylinder I28 at opposite ends of which the pipes l3 and I4 from the air control valve assembly are connected.

It will be understood by those skilled in this art that the piston 321 may be controlled either by the type of air control apparatus shown in Figs. 1 through ,4 or by the type of air control ap- V paratus shown in Fig. 5.

In Fig. 8 I have illustrated a still further modifled form of valve control apparatus which may be employed with my main piston and cylinder assembly, such modification including a spool valve 39a for controlling the inlet and outlet of oil into the cylinder chamber assembly 500., Iilb, [80, etc. The spool valve 39a is provided with a reduced section or recess I36 which is adapted to be aligned with either the oil inlet port I3I and a by-pass port 132, corresponding in all respects to the oil inlet port (.4 and by-pass port 5 illustrated in Figs. 1 through l, or with the oil inlet port I 3i and a port I32a which communicates with the recess 32 in the cylinder section Ifia in the same manner as was described with reference to Figs. 1 through 4, the valve 30a when in its uppermost position as shown in Fig. 8 exposing the port ItZa to the exhaust pipe 39. The upper end of the spool valve 30a is provided with an operating piston I33 which reciprocates within a valve operating cylinder I34.

To operate the valve 353a between its two posi 'tions, I provide for means for supplying compressed air below the piston I33, the source of compressed air, as in the preceding forms of the device herein described, being provided by the up stroke of the main piston I2. By referring particularly to Fig. 8, it will be noted that the uppermost cylinder section I90 is provided with an air intake port I35 spaced a short distance below the full up stroke position of the main piston I2 so that during the major portion of the up stroke of the piston I2 air above the piston will exhaust through the port I35. However, when the upper end of the skirt l2a of the piston I2 arrives opposite the port I35, it will close ofi this port and the air then remaining above the piston will be compressed in the upper end of the cylinder section i9c and be passed through an auxiliary port 36 and through a pipe I37 to the lowermost portion of the valve operating cylinder in their proper relation to allow exhausting of the oil from the cylinder assembly and permitting the piston to fall by gravity.

Now, however, as the piston approaches its lowermost limit of travel, the valve 30a should be moved downwardly to the position shown in Fig. 9 and I accomplish this result by providing an upwardly extending rod I38 secured to the upper end of the piston I2 and projecting through a suitable stuffing box I39 in the upper cylinder head Md. The rod I38 may be of any desired length sufficiently, however, that when the piston I2 is in its lowermost position an arm I lI secured upon the rod I38 will engage the upstanding end of a slide rod I 42 and depress this rod. The rod M2 is slidably mounted in a bearing I43 in the upper cylinder head I40 and also in a bearing I44 in the cylinder section Iiib disposed immediately above the valve operating cylinder I34. The lower end of the slide rod M2 is pro vided with a cup washer I 45 snugly fitting the interior walls of the valve operating cylinder I34 so that as the rod I42 is depressed air will be compressed by the cup washer I45 to force the valve operating piston I33 downwardly. The "lower end of the rod I42 is preferably of sufficient length below the cup washer I45 such that the lower end I46 thereof will mechanically engage the piston I33 should the piston fail to move downwardly under the influence of air compressed by the cup washer I45 though in normal operation a quantity of air compressed by the cup washer I45 will be sufficient to throw the valve 30a to its lowermost position by a substantially snap action. The slide rod I42 is normally held in its uppermost position as shown in Fig. 8 as by providing a compression spring l4! disposed between the upper cylinder head l ili and a bushing I l-i secured as by a pin I49 to the upper end of the slide rod I42.

In employing any one of the forms of cylinder and piston assemblies illustrated and described herein, the mounting of the cylinder and piston assemblies upon the arm 5 of the base 3 permits the accurate alignment of the piston I2 with the sucker rod 9 and permits the employment of the upper end of the sucker rod or polished rod as the piston rod for the power apparatus. The opposite arm 4 of the base 3 may then be em- ,ployed for the mounting of the fluid pump 65, tank 5% and tank 58, the arrangement preferably being such that the base 3 is substantially balanced upon opposite sides of the pivot post 2. Whenever it becomes necessary to repair the pump or the sucker rods or to remove the sucker rods or other part of the pumping apparatus from the well, the piston I2 may be lowered in its cylinder assembly, the plug I6 removed from the bottom of the cylinder section Ida and the nut 22 removed to disconnect the polished rod from the piston 1211, after which the polished rod may be lowered until its upper end is free of the arm 5. At this time the base 3 may be swung through an angle of 90 or more degrees to permit ready access to the casing, sucker rods, flow tubing,

etc., without interference from the power apparatus. When the power apparatus is to be again connected, all that is necessary is to turn the base 3 back to the position shown in Fig. 1 and connect up the polished rod with the piston I2. In order to assist in supporting the strains exerted by the weight of the sucker rods and the column of fluid lifted thereby, one or more legs I56 may be provided, either fixed or removably attached to the outer ends of the arm 5 of the base and adapted to rest upon the derrick floor or other support upon which the standard I is mounted.

It will be apparent therefore that in the form of the device illustrated in Fig. 8 the downward movement of the piston will both pneumatically and mechanically move the valve 30a to the position necessary to start the up stroke of the piston I2 while when the piston I2 approaches its uppermost limit it will act as an air compressor for supplying sufficient pneumatic force below the valve operating piston I33 to snap the valve 30a to its uppermost position ready for the down stroke of the piston.

It will be observed therefore that I have pro- Vided an hydraulic operating mechanism for reciprocating a string of sucker rods or similar devices for the pumping of oil from oil wells wherein the hydraulic force is applied to produce the up stroke of the sucker rods while gravity is depended upon for the down stroke thereof and in which the reciprocating movements of the hydraulic device is employed as a means for compressing a sufficient quantity of air upon each stroke of the mechanism to move the hydraulic control valves to the positions necessary to start the next stroke in a substantially snap action, thereby preventing the hydraulic locking of the system.

While I have shown and described the preferred embodiment of my invention, I do not desire to be limited to any of the details of construction shown or described herein, except as defined in the appended claims.

I claim:

1. In a fluid power operating device for pumps, a main cylinder, a main piston mounted for movement within said cylinder and adapted to be connected to the pump, fluid power control valve means for controlling the supply of fluid power to said main cylinder to cause said main piston to reciprocate within said cylinder, means for moving said control valve to its various control positions including an auxiliary cylinder, a piston therein coupled to said control valve, means for supplying compressed air to said auxiliary cylinder, and a pneumatic control valve for controlling the supply of compressed air to said auxiliary cylinder, and means coupling said pneumatic control valve to said main piston for actuation thereby during the final portions of the movement of said main piston as it approaches the end of its stroke.

2. In a fluid power operating device for pumps, a main cylinder, a main piston mounted for movement within said cylinder and adapted to be connected to the pump, fluid power control valve means for controlling the supply of fluid power to said main cylinder to cause said main piston to reciprocate within said cylinder, and pneumatic operating means for moving said fluid power control valve to its various control positions including means actuated by movement of said main piston for compressing air to supply pneumatic power therefor.

3. In a fluid power operating device for pumps, a main cylinder, a main piston mounted for movement within said cylinder and adapted to be connected to the pump, fluid power control valve means for controlling the supply of fluid power to said main cylinder to cause said main piston to reciprocate within said cylinder, and pneumatic operating means for moving said fluid power control valve to its various control positions, means actuated by movement of said main piston for compressing a quantity of air during one stroke of said piston in excess of the quantity required for the operation of said fluid power control valve for the nextstroke.

4. In a fluid power operating device for reciprocating pumps, a main cylinder, a main piston mounted for movement therein and adapted to be connected to said pump, a fluid power control valve means for controlling the supply of fluid power to said cylinder, pneumatic means for moving said fluid power control valve to one position to supply power to said cylinder to elevate said piston and to another position to exhaust fluid from said cylinder when said piston is to move in the opposite direction, means for compressing air above said piston during the up stroke thereof, and a pneumatic control valve actuated by approach of said piston to either of its extreme positions in said cylinder for supplying said compressed air to said fluid power control valve to move the same to the position for starting the next stroke of the piston.

5. In a fluid power operating device for reciprocating pumps, 2. main cylinder, a main piston mounted for movement therein and adapted to be connected to said pump, a fluid power control valve means for controlling the supply of fluid power to said cylinder, pneumatic means for moving said fluid power control valve to one position to supply power to said cylinder to elevate said piston and to another position to exhaust fluid from said cylinder when said piston is to move in the opposite direction, means for compressing air above said piston during the up stroke thereof, a pneumatic control valve engageable by said piston as it approaches the end of its up stroke, and movable thereby to a position to' supply said compressed air to the fluid power control valve to move the same to a position for starting the down stroke, means interconnecting said pneumatic valve with said piston for moving the pneumatic valve to its opposite position as the piston approaches its lower limit of travel to supply said compressed air to said fluid power control valve to move the same to its position for starting the up stroke.

6. In a fluid power operating device for reciprocating pumps, a main cylinder, a main piston mounted for movement therein and adapted to be connected to said pump, a fluid power control valve means for controlling the supply of fluid power to said cylinder, pneumatic means for moving said fluid power control valve to one position to supply power to said cylinder to elevate said piston and to another position to exhaust fluid from said cylinder when said piston is to move in the opposite direction, means for compressing air above said piston during the up stroke thereof, a pneumatic control valve engageable by said piston as it approaches the end of its up stroke, movable thereby to a position to supply said compressed air to the fluid power control valve to move the same to a position for starting the down stroke, means interconnecting said pneumatic valve with said piston for moving the pneumatic valve to its opposite position as the piston approaches its lower limit of travel to supply said compressed air to said fluid power control valve to move the same to its position for starting the up stroke, and means for latching said pneumatic valve in either of its positions.

'I. In a fluid power operating device for pumps, a main cylinder, a main piston mounted for movement therein and adapted to be connected to the pump, a fluid power control valve means for controlling the supply of fluid power to said cylinder to cause movement of said piston in one direction, and for controlling the exhaust of said fluid from said cylinder to cause said piston to move in the opposite direction, means communicating with said cylinder at the opposite side of said piston for receiving air compressed by said piston during its movement in said one direction, and a pneumatic valve actuated by approach of said piston to either of its extreme positions for supplying the air so compressed to said fluid power control valve to shift the same at the end of each stroke of the piston to its fluid power supplying or exhaust positions to start the next stroke of said piston.

8. In a fluid power operating device for pumps, a main cylinder, a main piston mounted for movement in said cylinder and adapted to be connected to the pump, fluid power control valve means for controlling the supply of fluid power to said cylinder to cause said piston to reciprocate therein, means engageable by said piston as it approaches the end of each of its strokes for compressing air, and means for supplying said compressed air to said fluid power control valve for moving said control valve to the position starting the next stroke of said piston.

9. In a fluid power operating device for pumps, a main cylinder, a main piston mounted for movement in said cylinder and adapted to be connected to the pump, fluid power control valve means for controlling the supply of fluid power to said cylinder to cause said piston to reciprocate therein, means engageable by said piston as it approaches the end of each of its strokes for compressing air, and for supplying said air so compressed to said fluid power control valve means to shift the same to a position starting the next stroke of said main piston.

10. In a fluid power operating device for pumps, a main cylinder, a main piston mounted for movement in said cylinder and adapted to be connected to the pump, fluid power control valve means for controlling the supply of fluid power to said cylinder to cause said piston to reciprocate therein, a second piston coupled to said valve to move the valve to its various control positions, means actuated by said main piston as it approaches the end of one of its strokes for compressing air upon one side of said second piston to move said valve rapidly to a position starting the next stroke, and means for compressing air by said main piston as it approaches the end of its opposite stroke and for supplying said air so compressed to the opposite side of said second piston to move said valve rapidly to a position starting the next stroke.

SAMUEL CLYDE KYLE.

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