US2355669A - Operating piston for oil wells - Google Patents

Description

J. MOSER OPERATING PISTON FO OIL WELLS Aug. l5, 1944.

Filed March 15, 1941 3 Sheets-Sheet l Y villa',

r11/III INVENTOR.

76.55 Maser y ATTORNEYS H NN 3 Sheets-Sheet 2 J. MOSER OPERATING PISTON FOR OIL WELLS Filed March l5, 1941 Aug. 15, 1944.

INVENTOR. cyle Maser ATTORNEYS Aug. l5, 1944. J. MOSER OPERATING-PISTO'N FOR OIL WELLS Filed March l5, 1941 5 Sheets-Sheet 3 INVENTOR 025156 M ikv ' passes throughs conduit H5. A cylinder |26 is provided with a piston |2| con- Patented Aug. 115., 1944 y 2,355,669 OPERATING ris'roN ron on. WELLS Y.lense Moser, Detroit, Mich., assignor to Vickers, Incorporated, Detroit, Mich., a corporation of Michigan Application March 15, 1941, serial No. 383,495V

Claims.` (Cl. 309-4) This invention relates to an operating piston for oil wells. l

It is an object oi the present invention to provide an oil well pumping apparatus which may be operated at relativelydiigh stroke speed without increasinlgl the normal capacity oi the pumps ordinarily used in these circuits. The invention is particuarly' adapted to what is known as the top control circuit, that is, a circuit in' which a -body of ,liquid connects the bottom sides of the balance cylinderand the motor cylinder directly while the operating pressure is introduced into the tops of the cylinders.

A further object of the invention is to provide a means for regulating the relative position ol; the pistons on the piston or polish rods to permit compensation for stretching o! the sucker -rods overapel'iodofuse. l

Another .object ot the invention relates to a novel meansof providing the extension incooperation` with the ordinaryv piston construction whereby an ordinary normally operating oil well f circuit can lhe changed to al high speed circuit by changing the piston construction and. utilizingthe same pressure source. f

Other objects and features of the invention .relating to details-of construction and operation willbe broughtv out in the following' description and claims. v l

In the drawings:

has been referred to as the top control circuit.

1-Fig. 2 illustrates acomplete power cylinder nstructed in accordance with the present inventiqn. v

- lFig. 3 is a sectional view of a piston and tail pipe showing the change-over construction.

Fig. 4 illustrates the piston of Fig. 3 prior to the change-over. .1

` Fig. 5 lsv-a modification of the device shown in Fig.. 3 showing a 'manner of obtaining the axial shifting between the polish rod and the piston.

4 3o Fig. 1 is a circuitdrawing illustrating what nected to the conduit 244 to cause shifting of the l `Iiig.` 6 illustrates a .polished rod clamp ,which I may4 be utilized -during the adjustment of the pistonl or during the change-over construction.

Referring tol Fig. 1, a motor cylindersl I5r has a Apiston Ill connected to a `rod ||1 ading into a,

well pipe lla.y The liquid delivered rom the 'weil accumulatoi` nected to 'a rod |22 on which-.is supported a weight '1.22. lit the` bottom o! pistonk I|5 is a housing |25 'and at lthe bottom of piston |20 is a.,

housing |25.` Thesetwohouslngs areconnected by a, pipe |2|. The cntrol unit f .or the apparaconduit 242 leads yfrom valvfe 24| back to an inlet 243 of pump 236. When valve 24|f connects con- Aeration. A spring A24|a acting on valve 24| serves tus is shown generally at 235 and this unit is connected to the top en d of piston I6 by a pipe |3611 and to the topend oi.'- cylinder |20 by a pipe IJla. Referring to this unit in detail, a main pump 236 is driven by a motor 231 and delivers liquid under pressure through a conduit 238 to a port 239 in a housing4 240 surrounding a pilot operated. valve 24|. The valve 24| is adapted to be shifted to connect conduit 238 eitherl to a conduit |31a leading Vtothe top of cylinder |20 or conduit |36a leading to the top of cylinder IIE. A

duit 238 with either conduit |3611 or |31a, the other of the conduits will be connected to return. conduit 242. Check valve 242:1 is provided'to permit filling oi'` the lines prior to starting thev op- 4 to'cause filling of the lines in the proper sequence. j v

Opposite ends of valve piston 24|A are connected by conduits 244 and 245 respectively, to a lever actuated valve 246. Valve 246 is connectedl by a bell crank. 241 and link 248 to contact members |39a and |39. The valve 246 is a simple pilot valve connected by a conduit 250 to a pilot vpump 251. When valve 2461s inthe position 4 shown, pressure from the pump 25| will be connected to conduit 245 and will pass to the valve 24| to shift it to the position shown. When pist0n ||6 reaches its uppermost position, theV con- Y tact'member |39 will eilect the shifting of valve 246 to a position where conduit 250 will be coneach endof the stroke of the piston and which Y will cause a shifting of the valve 24| and a change in the direction o1' shifting'of the pistons.

The replenishing inv this system is effected by a pump' 252 which receives liquid from a conduit 253 open to the ou'tlet of pilot pulnp 25| and directs liquid to a conduit 254 leading to a conduit aconstant replenishing of the body of liquid passingbetweencylinders ||5 and |20. The relief of the upper control circuit is effected by a shuttle valve 2|||. This valve has a central po't 2|2 which connects to a'conduit 2|2 a leading to a low pressure reliegalve 255. The conduit |36aA is alwaysJ connected y a conduit 256 tofone end oi" the shuttle valve 2|! andto a port`2 51adia' cent the port 2|2. The conduit |3`|a is always connected to the other end of valve 2|0 and a port 258 on the other side of port 2|2, When pressure is being directed from pump 236 to conduit |3'|a, the valve 2|0 will be shifted to the left as shown, so that supply conduit |36a is connected not only to conduit 242 but to low pressure relief valve 255. During replenishment of the body of liquid passing between the lower ends of the cylinders H5 and |20, relief of the upper system is permitted through valve 255. Similarly, if the system .is reversed, conduit |36a will be under pressure so that valve 2 |0 will shift to connect conduit I3'Ia to the relief valve 255. A relief valve 259 in conduit 250 is arranged to spill liquid into relief valve 255 at a more or less constant rate. This is possible since the pump 25| has a capacity which is quite adequate for the shifting of valve 253| and when the valve 24| is not being shifted, there will be a bypassing through the valve 259 to valve 255; there will thus always be a supercharging of the upper circuit control by the low pressure 'setting of valve 255. This will follow from the fact that conduit 2|2a is always connected to,the inlet or supply conduit to the main pump 236.

The valve i150, Fig. 1, in the base of cylinder |20 will serve to bypass excessive liquid in the lower circuit. The operating circuit of Fig. l could be varied by changing it from a closed to an open circuit. If this were done, check valve 24211 would be dispensed with and conduit 2&2 would be cut and the free ends dropped to the bottom of the tank.

Under ideal conditions, it would be possible t have the diameters of cylinders H and |20 exactly equal and the length the same so that the same quantity of liquid will be required to enect stroke of equal length in each cylinder. However, manufacturing tolerances in honing or nishing these cylinders result in a small variation in diameter. Due to the length of these cylinders, this small variation in diameter results in a considerable variation in the volume of the cylinders. It is necessary, therefore, to provide means for compensating for different volume requirements of the cylinders for the strokes of the piston. In the circuit of Fig. l the variations in the cylinder diameters are compensated for by the bypass or spilling valve |50 and the shuttle valves 2|0. The valve 2|0 automatically causes that pressure line connecting the cylinder whose piston is being moved downward to be open to either pilot pressure, that is, super-charging pressure, or to relief valve pressure.

The pistons I6 and |2| are each provided with extensions which may be referred to, respectively, as 300 and 30|. These extensions or tail pipes, as they may be called, pass through packing 302 at the top of the cylinders. The extensions have a. length slightly greater than the stroke of the pistons in the cylinders so that at the lower extremity of the piston travel, the extension will still be through the packing 302. This condition is shown in cylinder |5 at the right hand side of Fig. l. A dust cap 303 is provided above each of the cylinders, as shown in Fig. 2. It will thus be seen that the extensions 300 .and 30| always ll the space above the pistons in the cylinders ||5 and |20, thus reducing considerably the volume necessary to actuate the pistons. Since the working area above the pistons is reduced, the operating pressure will be higher. However, the speed at which an ordinary pump can stroke the apparatus is greatly increased because of the reduced volume requirement. For example, if the circuit of Fig. 1 is used with an ordinary piston, as shown in Fig. 4, with a sixty gallon vane pump, the pressure range would be from approximately 200 pounds to 450 pounds per square inch with a speed of 4 to 5 cycles per minute. Using the same pump, however, with the extensions 300 and 30|, as shown ln Fig. 1, the operating pressure would be from 400 pounds to 900 pounds .per square inch and the speed would be 8 to l0 cycles per minute. The vane type pump is Well adapted to the higher pressures and because of the low volume requirements, can increase the number of cycles considerably.

In some instances it is desirable to be able to change the slow type of job to the fast type of job or vice versa. In Figs. 3 and 4, a. construction which greatly facilitates this change-over is shown. This construction also discloses the feature which permits compensation for change in sucker rod length. In Fig. 4, within a cylinder 309, a piston is shown in two portions, a lower portion 3|!) and an upper portion 3| The construction of this piston is shown in detail in Fig. 3 where it will be seen that the lower portion 3|0 has a threaded axial opening to receive a threaded extension on the top portion. Packing for the piston is arranged between the two parts. In Fig. 3, however, the top portion of the piston 3| la is shown with the extension 300 which passes through a packing arrangement 3|2 held in place by a split ring 3|3. The polished rod is threaded in its upper end into a locknut 3|4. A set screw SI5 may be used to lock the two portions of the piston together. To facilitate the change-over, a clamp should be provided for the polished rod, as shown in Fig. 6. This clamp is located at the lower portion of the cylinder and consists of a split collar 320 with a suitable gripping surface 32| This split ring may be brought tightly around the polished rod i by tightening thetwo nuts 322 and 323. The clamp 320 will rest on the lower portion of the cylinder housing indicated at 325 and thereby hold the weight of the sucker rods while the pistons are being either adjusted on the sucker rod or changed from the common slow speed type of Fig. 4, to the high speed type'of Fig. 3. The cylinders 309 of Figs. 3 and 4 are identical and, to change to the slow speed operation, the split ring 3|3 is removed along with the packing 3 i2 and a, new and shorter dust cap 330 is used. The pressure entrance in this case is through a pipe 33| in the dust cap, the previous entrance of 332 being plugged at 333.

Another type of change-over piston is shown at 335 in a cylinder 336 in Fig. 5. This piston has packing 331 at the top portion thereof. In the center of the piston surrounding rod 330 is a sleeve 339 which'projects through the piston and above it for a, certain distance. This sleeve is threaded on its inner surface to permit adjust ment on the threaded polished rod 338 and is threaded on the outer surface of the upper end to cooperate with a lowerv end of a tube 340. At the lower end of sleeve 339 is welded a ring 34|. Packing 342 is provided in this ring held in place by a retaining ring 343. A ring 344 surrounds the upper portion of the sleeve 338 and between these rings, the piston proper 335 is found. A sealing band 345 surrounds the piston at the lower end and similar material is provided at the upper end, shown generally at 346. When the extension 340 is screwed down on the top end of sleeve 339, it compresses ring 344 against the packing material 346 and also moves piston 335 downwardly toward ring 34| thereby placing all I is provided, as ls customary, on the loi' the sealingmaterial under the proper compression. A set screw I" may be used to lock the extension i in place. If used, the set screw may be put in place by lifting the piston assembly t the point shown in Fig. 5 and prior to the application of the top connection plate and dust cap. The extension 340 is also heldin place against turning by lock nuts 348. The extension Il is provided so that the lock nuts will be easily accessible without removing the piston from the cylinder. When adjustment is desired, thelock nuts are loosened and the extension 340 turned so that the sleeve 339 will move upwardly or downwardly on the rod 338. During this movement there is no disturbing of the relative positions of the extension 340 and the sleeve 339. When the piston is properly adjusted on the rod, the lock nuts are again tightened. A dust cap top of the cylinder.

I claim:

l.,In an voil well pumping apparatus of the type having a motor cylinder and a counterbalance cylinder, a piston in said motor cylinder, a piston rod extending into said cylinder, means connecting said piston rod and said piston whereby the relative axial relationship between the two may be altered, said means comp/rising a sleeve threaded on said rod, a iiange projection rigidly fastened at one end of said sleeve, a retaining ring I at the other end slidable on said sleeve, and means for locking said piston between said flanged end and said retaining ring. 2. In an oil well pumping apparatus 'of the type having a motor cylinder and a counterbalance cylinder, a piston in said motor cylinder, a piston rod extending into said cylinder, means connecting said piston rod and said piston whereby the relative axial relationship between the two may be altered, said means comprising a sleeve threaded on said rod, a flange projection rigidly fastened at one end of said sleeve, a retaining ring at the other end slidable on said sleeve. and means for locking the piston between said flanged, end and said retaining ring comprising a tubular extension threaded a`t one end of 'said' sleeve and lock nuts for preventing the turning of said extension on said rod except during adjustment.

3. In a reciprocating motor for a hydraulic system. a cylinder. a piston therein, means ,for

the inlet and outlet of pressure liquid at the ends volf the cylinder for reciprocating the piston in the cylinder. a piston rod extending through one end of the cylinder, a. rst piston part in the cylinder. a second piston part in the cylinder, sealing means for wiping the cylinder walls disposed" between the piston partsscrew thread means for connecting the two piston parts and for clamping the sealing means therebetween, said piston parts having aligned axial openings therethrough for receiving the piston rod, means detachably connecting the piston rod with the second piston part, a hollow extension on the second piston part of less diameter than the piston and extending out throughthe end of the cylinder opposite the piston rod, packing means through which the hollow extension projects,

said hollow extension having a length at least A equal to the length of the stroke of the piston, the hollow extension serving to reduce the volumetric capacity of the cylindert on one side of the piston, and 'means in the hollow extension for locking the connection between the second piston part and the piston rod.

4. In a reciprocating motor for a hydraulic system, a cylinder, a piston therein, means for the inlet and outlet of pressure liquid at the ends of the cylinder for reciprocating the piston in the cylinder, a piston rod extending through one end of the cylinder, a rst piston part, a second piston part, sealing means for wiping the cylinder walls disposed between the piston .parts, screw thread means for connecting the two piston parts and clamping the wiping means therebetween, saidpiston parts having aligned axial openings therethrough for receiving the piston rod, said piston rod being threaded at its end,

cooperating threaded means associated 'with the second piston part for uniting the piston rod and the second piston part, a hollow extension on the second piston part of less diameter than the piston and extending out through the end of the cylinder, packing means at the last mentioned end of the cylinder, the hollow extension having a length at least equal to that of the stroke of the piston and servingto reduce the volumetric capacity of the cylinder on one side of the piston, and screw threaded means4 in the hollow extension for locking the threaded connection between the piston rod and the second piston part. n

5. In a reciprocating motor for a hydraulic system, a cylinder, a piston therein, means for o the inlet and outlet of pressure liquid at the ends s tituting a part of the piston and having a diameter less than that of the piston and extending through the end of the cylinder and serving to reduce the volumetric capacit;y of the cylinder on one side of the piston. screw thread means for connecting the piston parts and clamping the wiping means between said portions, said piston having anaxial opening therethrough for accommodating the piston rod, and screw threaded means in abutting relation with a part -of the piston and engaging the threads of the piston rods for connecting the piston rod to the piston.

JESSE MOSER.

CERTIFICATE 0E CORRECTION'. patent No. 2,555,669.

e JESSE MOSER.

August 15, 19ML.

Itis hereby certified that error' appearsA in the-prihted epecificationof the above numbered patenti requiring correction as follows.: 'Page 5 first column, line 51,-c1aim l, after "ring" strike ot the numeral' "5MM that the said Letters Patent should be read with this correction therein that thesame may conform toV the A:record of the case ih the Patent Office."

signed and sealed this 21st day 0f Novemmar, A. D. -1944.

Leslie Frazer (Seal) Acting Connnissioner of Ptents.

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