US2363142A - Hydropneumatic pumping jack - Google Patents

Description

Nov. 2l, 1944. w. B. REED HYDRJPNEUMATIC PUMPING JACK Filed June 5, 1941 F i5 WARREN BIEE, B Y fm QQM.

DTTONEY.

Patented Nov. 21, 1944 UNITED STATES PATENT OFFICE mnoPNEUMA'rrc PUMPING .Tacx warren n. need, New orleans, La.

Application June 5, 1941, Serial No. 396,700

2Claims.

The invention herein described and illustrated is related t my previous application Serial No. 202,440, led April 16, 1938, entitled Hydropneumatic power unit, now Patent No. 2,279,057, and also to my companion application, Serial No. 396,699, for Pressure control for hydropneumatic motors for pumping umts, filed of even date herewith, now abandoned.

The invention pertains to and'includes a multiplicity of elements in combination embodying improved details of construction to improve the emciency of a hydro-pneumatic jack for a reciprocating pump.

An object of the invention is to reduce the `height of the unit by disposing the gas chamber axially around the cylinder of the unit and to eiect an insulating space thereby conserving the cylinder heat and tending to 'equalize the heat changes in the gas chamber.y

An object of the invention is the substitution of a piston tube for a piston rod providing for an adjustable entrance of the polished rod into the piston tube and a combination clamp between the two.

Another object of the invention is to so combine the cylinder with its base and top closure that the annular dashpot extensions from the two ends into the cylinder base will be positively aligned and concentrically spaced by means of a circular tongue and groove construction at each end.

Another object of the invention is to provide an assembly of piston elements combining of the upper and lower travelers in an annular shaped dashpot plunger form holding the upper and lower spaced leather piston cups serially arranged on and aiilxed to the piston tube to reciprocate therewith.

Another object of the invention is the continuous hydraulic decelerating relief means in the dashpot extensions and the further gas cushion and stop in both the upper and lower dashpots.

A further object of the invention is to assemble the housing, the cylinder, cylinder cap and base element of a hydro-pneumatic pumping jack into a rigid unit.

Other and further objects of the invention will be readily apparent when the following description is considered with the accompanying drawing wherein:

Fig. 1 is a vertical sectional view of the assembled reciprocating pumping jack;

Fig. 2 is a larger scale view of the lower end of the piston tube and polish rod clamp.

Fig. 3 is a side elevation looking at the side of Fig. 2. Y

Fig. 4 is a transverse section on line 4-4 o! Fig. 1 showing the concentric arrangement of the gas chamber and cylinder.

In Fig. 1 the numeral I denotes the cylinder with the base 2 bolted thereto. A cap 3 closes the top of the cylinder I, and the gas chamber housing 4 is threaded at its lower end to a shoulder on the cylinder at 5 and at its upper end threaded to ange 6 at 1. 'I'he cap flange 8 is shown bolted to flange 6 of the housing. These bolted iianges contact at the annular ring 9 and bring under compression the circular tongue and groove Joint Ill between the grooved cylinder closing end 3 and the circular tongued end of cylinder wall I.

This construction takes all upward piston thrust from the cylinder wall I and places it on the bolted flanges 6 and 8 and in turn to the gas chamber housing 4 which relays any strain to the heavy shoulder at the lower end of the cylinder at 5.

The annular depending ring II from the cap iiange 8 ts into the recess formed by the annular ring I2, seated in the shoulder I2a turned in housing 4 so as to compress the packing rings I2b forming a gas seal to the gas chamber I3, which comprises the cylindrical area between the cylinder wall I and the inner wall of housing 4. The spacing between walls I and 4 may be maintained by lugs I4on the cylinder wall I. Multiple holes I5 through the cylinder closing end 3 permit the passage of gas between the interior 20 of cylinder I and the gas `chamber I3.

A cock I6 may be provided to relieve excess gas pressure from the gas chamber or any oil which may accumulate or be placed in the gas chamber to adjust its gas volume.

The valve I1 is to control entrance from a gas pressure source of gas into the gas chamber I3 and the cylinder space 20 above the piston therein. A plug I8 closes a vent for air expulsion when filling the cylinder 20 and gas chamber with gas pressure or as a means to introduce oil I9 into the cylinder 20 above the piston to be carried thereby and to form the medium for into the base 2 at 29 at an angle thereto.

sleeve 23 is spirally perforated by a series holes 25, this spiralline of pertorations may extend from about two inches above the bottom of the dashpot area or space to almost the top of the extension sleeve 23. -The sleeve 23 is also provided with a small vertical passage 26 which is closed by a cock 21.

Surrounding the dashpot area 24 there is provided an annular space or gas chamber 24a. 'This annular chamber.is connected with dashpot area 24 by the shortening of the inner wall of cylinder I or otherwise, forming thereby a continuous circular passage or connection between the gas chamber 24a and the iluid in the interior of cylinder 20. A drilled outlet 24h with closure at 24o provides means of injecting gas or emitting fluid as may be desired. The cubical content or volume of the annular gas chamber 24a is designed to be approximately that of the volume of the dashpot area, 24 that lies below the last of the openings 25 therein.

A conduit 28 leading from an intermittently timed fluid pressure source is shown threaded The base 2 is extended downwardly to provide for adequate stuiiing box with packing 30 and bolted gland 3| sealing about the reciprocating piston tube 32.

'I'he upper end of piston tube 32 is closed and reinforced by a plug 33 having a shrink iit so as to become an integral lpart of tube 32 which may be welded at the possible leakage between the plug and tube. The tube 32 has a small collar 34 welded thereon which collar has a depending lower piston traveler and dashpot plunger cup 35. The upper end of the cup 35 is shaped to receive the downward facing leather cup 36 which also ts closely about the tube 32. Above this leather cup 36 is placed a spacer member 31 shaped to hold the lower cup 36 and an oppositely disposed leather cup 38 which is in turn tted onto the shaped end of the upwardly extending piston traveler and dashpot plunger cup and skirt 39.

Around the piston tube 32 and in a circular recess inside the cup 39 is placed a small packing ring 40 with a packing gland 4| held against said packing 40 by nuts 42 and 43 threaded onto the reinforced end of tube 32. These nuts also hold the entire piston assembly in sealing position and joined to the piston tube 32.

The outer suface of the upper and lower piston traveler cups and skirt 35 and 39 are in slidable contact with the inner wall of the cylinder I and may be provided with a number of circular oil grooves such as 44 and 45. The upper traveler cup and plunger 39 is preferably cutl away for a part of its length as shown, to lessen the friction `of too long a cylinder contact, leaving the upper extension 46 toenter the dashpot area. The inner face 41 of the extension 46 slidably contacts with denite tolerance the outer wall of the depending sleeve 49 and therebytraps the oil and gas above the piston within the dashpot area 48. As the piston ascends the trapped oil will be forced through the holes 50. 'I'hese holes are closed one by to increase the'deceleration of said piston travel until the last hole in the series is closed, and to simultaneously isolate the gas volume in the dashpot chamber so as to increase the gas compression. There will be left in the dashpot area or chamber an isolated compressed gas volume extending from the uppermost hole 50 to the end of the said chamber. This gas is trapped by the plunger 43 and the oil between the outside cut away surface and the cylinder wall. This compressed gas cushion will provide the ultimate cushioned stop if the piston is still in upward mgggrring to Figures 2 and s, a portion or the lower extension of base 2 is shown with piston tube 32 extending through the packing. and bolted packing gland 3|. Extending upward into tube 32 is shown 4polished tice carries the entire well load.

At the end of piston tube 32 a. sleeve 53a is attached which forms a circular shoulder over which the circular recess in two halves of clamp 52 can be bolted as at 53. The clamp 52 then is flxedly bolted to the adjusted polished rod 5| by the bolt assembly 54 thereby eil'ectively connecting the piston tube 32 and the polished rod 5I and connecting the well load to the piston tube 32 to be reciprocated thereby.

The cross section in Fig. ing between the housing 4 lugs I4 to provide the cylindrical gas chamber area I3 and also shows the depending sleeve 49 showing one of the holes 50 of the spiral series of decelerating openings.

In operation the piston is elevated by the intermittently timed pressure controlled liquid admitted through conduit l28 and is lowered sequently by the gravity load suspended to the piston tube by the polished rod and tube clamp top to the tube to prevent any one as the extension 46 covers them and aided by the expanding of the controlled compressed gas volume in the cylinder above the piston and the surrounding gas chamber.

On the upward stroke of the piston the pressure of the controlled gas volume in the cylinder above the piston and connected gas chamber is compressed and at a given point in the piston travel the increasing pressure above the piston and the decreasing pressure of the fluid below the I piston together with the downward pull of the well load will be equalized and the piston will come to a balanced rest. These forces are so adjusted in practice that this balanced rest at the,

normal stroke length will occur a few inches below the depending dashpot sleeve.

Should this adjustment become disturbed the balanced resting point may result in a longer or shorter stroke and even enter the dashpot and in an extreme case should the ascending piston be relieved of a part or all of its well load, then there will be no balanced stop and. the piston plunger will enter the dashpot `area with more or less velocity to be decelerated and gas cushioned,

`thereby preventing a metal to metal contact or stroke injurious to the mechanism.

On the normal downstroke the piston is similarly brought to a balanced rest at some desired point above the lower dashpot. l An unbalanced condition may compel the descending piston plunger to enter the dashpot, but the maximum down thrust can never be as great as is possible in the upper dashpot. As the descending piston cup enters the dashpot area 24, the trapped oil discharges with increasing velocity through the progressively decreasing number of holes 25 to produce an eilective deceleration of the piston travel.

In order to obtain a combined hydraulic decelerating action followed by a pneumatic cushioning stop in the lower dashpot, the communicating gas chamber 24a isv added and filled with gas.

with or without' initial pressure as may be desired. This gas is under compression in varying amounts during each stroke and its volume varies rod 5|, which inv prac- 4 illustrates the spacand cylinder I by the :,seawa proportionately. but as the total volume or cubical content of the chamber 24a is approximately the same as that of .the plunger area 24 below the last hole 25, any further downward movement of the piston plunger 36 below the last hole 25 will force the trapped oil into the gas chamber 24a, raising the pressure until the descending piston is brought .to a gas cushioned stop so that a metal to metal contact is impossible.

The cock I6 is a drain for possible accumulation of splashed oil at the bottom of the gas chamber I3 and also may serve as an outlet to reduce gas pressure in the chamber, it being obvious that the gas volume ofthe chamber i3 may be adjusted at will by placing more or less oil in the said gas chamber. Y

This adjustable volume of the chamber I3 is of value in adjusting the gas chamber for a greater or lesser pressure peak due to the piston stroke.

When the pumping jack is installed the conduit 28 connecting the oil pressure source to the cylinder base 2 is, of course, illed with air. To eliminate this air the piston is lowered into the dashpot as far as it will go and the air vent cock 21 is opened. Oil from the pressure source is then let into the conduit 28 which as it fills with oil expels the air above through the passage 26 and cock 21. When al1 the air possible is expelled oil will begin to ow from the cock 21 which is then closed. 'I'here may still be a negligible quantity of air trapped in the top of 4the depending cup 35. As the piston functions there will be, of course, a full cylinder of oil below the piston.

What is claimed is:

1. In a hydro-pneumatic pumping apparatus a power cylinder. a working barrel therein, a piston having a sucker rod from the well connected thereto and movable by liquid pressure from below to pump the well, a compression chamber having a uid therein t0 be compressed by movement of said piston with'a view of bringing the piston to rest on the upstroke when the forces on the piston become balanced, said chamber being disposed about said working barrel, and a dash pot construction to hydraulically bring said piston to a positive stop including intertting sleeve portions on said cylinder and piston having a series of openings 4to be progressively closed as said sleeves interfit so as to progressively resist the escape of fluid from said dash pot.

2. 1n a hydro-pneumatic pumping apparatus a power cylinder, a working barrel therein, a piston having a sucker rod from the well connected thereto and movable by liquid pressure from .below to pump the well, a compression chamber having a fluid therein to be compressed 'by movement of said piston with a view of bringing the piston to rest on the upstroke when the forces lon .the piston become balanced, said chamber be-

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