US2414979A - Hydropneumatic well pumping system - Google Patents

Description

Jan.`28, 1947. J. F. Ross HYD'ROPNEUMATIC WELL PUMPING SYSTEM Fil-ed'oct. 24, 1941 l Sheets-Sheet 1 Jan. 28, 1947. J. F. Ross y HYDROPNEUMATIC WELL PUMPvING SYSTEM Filed o'ct. 24, 1941 2 .sheets-sheet 2 s 72 73 i 77 75/V 76 g 2* B3 j //l1///// 83 /k 76s A i f 4 A 76 az g 7 77 82 'F i g5. y J'Amsa E Ross INVENTOA 88' I' BY aan F VIT'mRNEY.

.Patented 28, 1947 UNITE-D STATES l PATENT OFFICE James F. Ross, Laredo, Tex.

Application October 24, 1941, Serial No. 416,303

1 The invention relates to a. hydropneumatic Well pumping system and particularly to the control of counterbalancing and uid storage features In my prior copending application, Serial No. 216,093, nled June 27, 1938, for a System of pumping wells, there is a detailed disclosure of an entire hydropneumatic pumping system, and in my copending application, Serial No. 308,334, filed December 9, 1939, there are disclosed various forms of different modiiicationsof the control valves and iluid storage assembly.

The present invention contemplates that considerable increase in eiliciency of the power pump 'may be eifected'by providing a mechanism or assembly by which the actuating liquid and the pneumatic pressure fluid are excluded from each other.

Another diiliculty has been encountered in hydropneumatic units where a pneumatic iluid is utilized to maintain a balance or counterbalancing pressure on theactuating liquid because the iluid and the liquid have a connecting interface which permits contamination of the liquid by the gaseous Iluid. -This difiiculty is enlarged upon where higher pressure is utilized because it has been found that air or gas will be more rapidly absorbed by the actuating liquid and in such quantities that the actuating liquid being circulated cannot be eiiiciently handled by a power pump because such actuating liquid contains compressible gaseous fluids. y

With theforegoing difficulty `in mind, the present invention contemplates an assembly wherein the actuating liquid is conned in one chamber,

the pneumatic fluid in another chamber, and a reciprocable pressure plunger arranged for a oating movement between and within both such chambers. O

The term "iluid will be employed to designate the gaseous pressure fluid used to load the actuating liquid, and the term liquid will be employed to designate the actuating liquid used to operate the pumping jack. One of the objects of the invention is to provide a fluid chamber and an actuating liquid chamber with a pressure plunger floating within and between the two chambers so that the actuating liquid may be loaded with a predetermined pressure. .l

Another object of the invention is to load the actuating liquid in a hydropneumatic pumping system for wells with a predetermined pressure to eiect the balance and counterbalance where such pressure is applied by a differential pressure plunger subjected to relatively high pneumatic pressure.

Another object of the invention is to provide stricted.

Another object is to so locate the auxiliary res a hydropneumatic pumping system for Wells with a differential pressure plunger which will move `with the flow of the vide a reversing valvefor hydropneumatic well pumping systems which will have a delayed action at one end of the stroke and a more rapid action at the opposite end of the stroke.

Still another object of the invention is to provide a control system forI hydropneumatic well pumping systems wherein leakage of actuating liquid will be returned either manually or automatically during operation to the system'whenever the volume of actuating liquid in the system is depleted to a predetermined extent. y

Still another object of the invention 'is to provide a device in a hydropneumatic well pumping system which will either manually or automatically replenish during operations the supply of actuating liquid whenever the volume of the liquid falls below a predetermined amount.

It is `also an object of the invention to reduce thesize and cost of the uid chamber by storing the loading gaseous uid 'under high pressure in a smaller chamber than heretofore used with lower pressures.

Another object of the invention is to utilize l high pressures in ahydropneumat'ic well pumping system so as to employ smaller and more efficient equipment and apparatus.

Another object is to provide a simple, eilicient and compact pilot valve to control the operation of the reversing valve. l

Another object of the invention is tp provide an auxiliary reservoir of actuating liquid to be supplied to the system, which reservoir is maintained at a pressure slightly under or lower than the pressure coming 4from the jack so that the supply of liquid to the system may be replenished from said pressure source when the supply of pressure liquid from the pumping jack is reervoir of actuating liquid that the pressure 'to be maintained thereon will berprovided by the action of the oating plunger supplemented by leakage of uid or liquid into said reservoir from the iluidv chamber and from the main liquid chamber.

A still further object is to provide a pump jack construction and operation which willcause the rsupply of actuating liquid to be automatically replenished.

Fig. 2 is a section taken on the .line 2-2 ol?V Fig. 1, looking in the direction of the arrows.

Fig. 3 is a vertical sectional view of the pump jack cylinder and ram illustrating themechanism 4for causing the replenishing of the actuating liquid. l t

Fig. 4 is a vertical sectional view of the pilot valve construction used to actuate the reversing valve.

Fig.l 5 is a vertical sectional view through the compressordevice used to compensate for loss of pneumatic uid.

Fig. 6 is a vertical sectional view of a iluid iiow retardingvalve for delaying the action i' the reversing valve in one direction.

In Fig. 1 the diagrammatic view illustrates the control mechanism for the pump jack ram. The jack cylinder 2 is mounted on the Well head 3 and is arranged to receive the sucker rod 4 which. extends upwardly from the reciprocating pump in the bottom of the well. This jack cylinder is best seen in section in Fig. 3 wherein the sucker rod 4 extends upwardly into the cylinder and projects at 5 through the top thereof. This cylinder carries a ram 6 which supports the rod by the adjustment clamp 1. The details of this pump jack will be later described.

In order lto elevate the ram `E and the string of rods 4 so as to elevate the oil inthe well, a pipe 8 is connected into the base of the cylinder 2 to conduct an actuating liquid to and from the cylinder in effecting the pumping operation. This pipe extends for any desired distance/to a point where it is connected with the reversing valve IIJ. This reversing valve is disposed in the system and controls the flow of liquid to and from the pump jack. This valve I0 is in turn shown ,in detail in Fig. 2 and will be described in detail hereafter. s

An actuating liquid" pump I2 has its inlet and discharge connected to the valve housing I8 so that in operation the valve I0 may be used to reverse the direction of ow by either directing liq.- uid from the pump through the pipe 8 into the pump jack cylinder to elevate the ram and sucker rods, or upon reversal of the valve I0 the intake of the pump is connected to the pump jack cylinder. The valve I 0 has therefore been designated as a reversing valve.

In order to avoid placing the entire load on the upstroke of the jack upon the pump I2 and the.

motor which operates it, and to, in turn, take advantage of the force of gravity on the downstroke of the jack which tends to force the actuating liquid out of the pump jack cylinder 2, a vbalance and counterbalance unit has been provided. This unit is shown generally at I5. The

4 f to the pipe 20, whereas, the actuating liquid will be forced by fluid pressure out of the cylinder I8 when the valve I0 .is reversed and the suction of the pump is connected to the pipe 20.

In other words, the pump I2 will run continuously to discharge the actuating liquid coming from the jack into the cylinderl and to receive such liquid from the cylinder I8, depending upon the position of the valve I0. The chamber I8, therefore, serves as a reservoir or source of actuating liquid for the pump.

It the pump I2 were compelled to provide all the power for the elevating of the rod and uid load of the well, it would be subjected to a maximum power demand on the upstroke and the motor would run idle on the downstroke. It is most efficient for the motor and pump to run continuously and be loaded uniformly because a smaller motor and pump may be' used. To accomplish this it is desirable to store not only the energy of the pump during the downstroke, but to also' utilize the energy of the actuating liquid due to the gravitational force of they load in the well. It therefore seems apparent that the operation of the-pump and the pumping action of the pump jack can be balanced and counterbalanced by applying a predetermined and desired pressure to a plunger such as 25. This pressure on the plunger 25 will assist in the discharge Vof liquidfrom the chamber I8 and, in turn, retard the introduction of liquid to the chamber. With this in mind the plunger 25 is provided with an extension or shank 26 which extends into the pneumatic chamber I9, and it will be noted that the extension 26 is of considerably lesser diameter than the head 25. The relative sizes or proportions of the head 25 and the extension or plunger 26 can be so adjusted that any desired diiferential pressure may be maintained upon this extension, or said head and extension may be of equal cross sectional area as is sometimes desirable under certain pumping conditions.4

For instance, if a ratio of 10 to 1 is desired, the area of the head 25 will be ten times that of the cross sectional area of the extension 26. Thus, a relatively high pressure of the pneumatic uid in the chamber I9 can be utilized. This I plunger 25 is thus disposed in a floating position between .the actuating liquid 21 in the chamber I8 and the pressure uid 28 in the chamber I9 but the plunger will be urged against the liquid '21 in the chamber I8 by a predetermined and substantially constant pneumatic pressure uid 28.

In order to control the operation of the entire device in accordance with the flow of actuating liquid, a pilot valve 30 is arranged to be actuated by the arm 3| which is, in turn, connected thru the rod 32 to the projection 33 on the plunger in the chamber I1. Thus, when a predetermined volume of actuating liquid 21 has been drawn from the cylinder I8, due to the suction'of the pump I2 and the differential pressure on the plunger 25, the pilot valve 30 will be moved from the position-shown in Fig. 1 to its alternate position. The movement of this pilot valve is accomplished when the arm 3| engages an adjustable stop 34 carried by the valve rod 35. The adjustable member 34 is Weighted on one side at 36 so that its adjustment will not be inadvertently changed. A similar adjustable member 31 is also positioned on the rod 35 so as to be engaged by the linger 3l on the reverse stroke of the plunger 25 when the pump jack moves to its lowermost position. In other words, when a predetermined volume of liquid yis forced from the actuating chamber I8, the pilot valve will be i moved and on the other hand, when a predeter- This recess 44 is therefore lled with an air,'

gas or other compressible iluid under pressure when it is in the position shown. When, however, the plunger 25 causes the pilot valve to be moved to the left, the recess 44 will move into alignment with the port 45 in the housing 43 and .this will allow the illiid under vpressure to discharge into the pipe 48 leading to the sleeve 41 on the end of the reversing valve I0.

In this manner a iluid under pressure will be introduced into the passage 48, (see Fig. 2) in the sleeve 41 which will act upon a piston 49 therein, tending to move the valve member 50 of .the reversing valve.

Another recess 52 in the pilot valve member will, at this time, move intor alignment with the pipe 42 and in turn'be charged with a uid under high pressure. When the plunger 25 reverses its movement and contacts the adjustable member 31 to move the pilot valve to the right, then the recess 52 will be moved to the position shown in Fig. l, whereupon the fluid under pressure in the recess 52 will discharge into the port 53 and a pipe 54 leading to the sleeve 55 on the other end of the reversing valve II).l This fluid will, in turn, act upon the piston 56, (see Fig. 2) which is similar to the piston 49, and cause the reversing ofthe valve member 50 to itsopposite position. It will be noted that the ports 45 and 53. are uncovered as the pilot valve makes its stroke, so as to allow `for the discharge of any pressure remaining inythe pipes 46'and 54. Thus, it will be apparent that by the reciprocating movement of the pilot valve 30 that the reversing valve is alternately moved in accordance with the oating movement of the plunger 25.

It seems obvious that due to pressures in the chambers I8 and I9 there may be some leakage therefrom into the central area or chamber I1 through the stuiiing boxes 60 and 60' respectively because of the lower pressure therein. Chamber I1 which entirely surrounds the plunger 25 and the extension 26 is utilized as an auxiliary pressure retaining storage reservoir in which' to trap and conserve the leakage from said chambers. Said reservoir is also employed for storing an additional reserve supply of actuating liquid which reserve should be maintained therein in sufiicient volume .to compensate for all liquid leakage occurring around thepump Jack or elsewhere from the system and to automatically lubricate the plunger 25 andthe extension 26.

Liquid in said auxiliary reservoir will naturally gravitate into the 'lower portion thereof as shown in the drawings while the pressure fluid collecting therein will accumulate above the liquid level which pressure fluid however is not specifically indicated in the drawings. Pressure is alsogenerated in said reservoir by reciprocation of the plunger 25 which displaces a certain amount of the liquid and iiuid in said chamber during each downstroke of the pump jack. The reservoir l1 may be maintained at any desired pressure below that coming from the pump jack during its downstroke which maintained pressure facilitates the passage of liquid from' said reservoir through pipes 6I and 8 and aids the motor unit` and pump in injecting said liquid into the chamber I8, as is more fully described in the following paragraph:

Inasmuch as the system will operate upon a predetermined volume of actuating liquid it seems obvious .that if liquid leaks from the chamber I8 or from around the jack or elsewhere from the system in suillcient quantity to permit the end of the ram 66 to descend into the dash pot construction on the lower end of the jack cylinder, there will then be a reduced pressure in the pipes 8 and 8|, due to the fact that said dash pot is provided with a by-pass 88.which restricts, and may be regulated as desired to limit the escape of liquid from under the descending ram. Restricting the ilow of liquid from the dash pot increases the pressure therein and gradually cheeks the momentive and gravitational descent of the ram while at the same time such restriction decreases the pressure in the pipes 8 and 6I to a point below .theuid pressure maintained in the auxiliary reservoir I1, whereupon liquid is automatically forced from the bottom of said reservoir through the pipes 6I and 8 to the pump I2 and thence into chamber I8 without interruption of continuous pumping operations.

The pressure in the reservoir il can be increased by applying a source of pressure to the pipe 61 on top of the housing, and a popof valve 68 may be used to insure the release of any pressure accumulating above a predetermined amount for which this valve may be set. On the other hand, still another valve 69 may be provided to allow the inlet of air from the atmosphere if the pressure in the chamber falls below a predetermined amount. A one way valve 6I is provided in the pipe 6I to prevent high pressure liquid in the closed system from entering said auxiliary reservoir I1. a

A double action air compressor arrangement is shown at 10 in Fig. 1 and in section in Fig. 5. This compressor is utilized for the purpose of maintaining a predetermined fluid pressure on the system. The compressor embodies a housing 14, an actuating piston 15 and two compression plungers 16 on the opposite ends. thereof which reciprocate in Vthe cylinders 11. Pressure actuating liquid forreciprocating the piston I5 and the plungers 16 is supplied through pipel19 on one stroke of the pump jack and through pipe 89 on the alternate stroke of the pump jack. During the upstroke of the pump jack, pressure in the liquid pipes 8 and 19 is suiliciently high'to overcome the pressures then existing in pipes 28 and 80 and to cause movement of the piston 15 to the right as shown in Fig. 5 and such movement causes the right hand plunger 18 to compress and discharge air .from the right hand cylinder 11, through check valve 83 and pipe 13 into the high pressure air line 1I which leads through pipes 42 and 4IV tuating liquid pipes are reversed and the piston and plungers wi1l-move to the opposite or left hand end of their stroke and in like manner comamm press and discharge air'froni the left hand cylinder through pipeJZ and thence into. the storage Achamber I9. Said movement to e left meanwhile causes .the right hand cylinder to reiill with air available for compression during the next succeeding upstroke which completes the compression cycle. As the air compression plungers 'I6 are constantly immbersed in liquid it is therefore possible to generate high pressures without undue heatingwand thus automatically maintain any" desired high pressure inthe chamber I9. .A pop valve 40' may be set as desired to release any excess pressure existing in the system.

In pumping modern deep oil wells, especially when operating at high speed, a too rapidchecking of the momentive and gravitational forces generated b y the weight of the descending rods will cause very destructive shocks and stresses to the sucker rods and pumping equipment. This damage is eliminated or nulliiled by employment of the fluid flow retarding valve 88', Fig. 6 which acts to slow down as desired the action of the reverse valve I at one end of its stroke. The valve 88 has a hinged disc 89 therein which permits a. free flow of fluid ypast said disc-in one direction but` which may be regulated by the adjusting screw 92 to check or limit the flow of fluid in the opposite direction thereby slowing down the operation of the reversing valve I0 as desired.

A modification of the application of said iluid retarding valve 88' consists in introducing a similar or substitute ilow retarding valve in one of the lines 46 or 54 which supply air to actuate the rechamber thereon, a pneumatic fluid chamber thereon, a differential pressure plunger freely supported' to float between said lchambers to maintain a predetermined pressure on the liquid lin the'liquid chamber due to the pressure of the fluid in the pneumatic chamber, means in said housing to receive the leakage from each of said chambers, and means to exhaust the pressure fluid and to return the liquid to the system.

2. In a hydropneumatic well pumping system where an actuating liquid is loaded with a pneu-4.

matic tluid, a .plunger disposed between the liquid and Iiuid, said plunger being disposedl to float between the liquid and iluid to transmit movement to one or the other depending on the predominant force, said plunger having different sized exposed surfaces in said liquid and fluid so as to obtain .a diiierential in pressures, said plunger being hollow and open to the pneumatic yspective chambers, a pressure plunger freely verse valve Ill thus slowing the'movement of said reverse valve at one end of its stroke. A further modification of such mechanism consists of eliminating the adjusting screw, 92 and providing or boring a hole or passageway through the disc 89 of proper size to limit the iluid flow past said disc, to the proper amount to slow down the action of the reversing valve I l! as desired.

It is to be understood that under normal operating conditions a sufficient volume of liquid should be maintained in the system to prevent the lower end of the ram 66 from entering the dash pot 65. In other words, the downstroke of the ram is preferably terminated approximately as shown in Fig. 3.

The pump I2 is operated by means of a drive` wheel 85 which may be driven by a belt or a suitable motor.

The reversing valve I0 may have suitable control valves, such as 86 and 88 thereon to control thev action thereof because it is desirable that it be operated so as to avoid any shock to the system. Suitable vent valves 81 may alsol be provided if desired.

It is to be understood of course, that all the pipe connections have suitable valves and vents therein as may be desired to maintain and control the pressures.

A pipe `9ll is shown in Fig. 1 which may serve as a drain or filler for the system or the pump l2.

Broadly, the invention contemplates a hydropneumatic pumping system wherein the pressures are automatically maintained for actuating liquid and replenishing the actuating liquid and wherein the pressure fluids are excluded from each other so as to provide an economic and successful pumping system.

What is claimed is:

1. In a hydropneumatic pumping system for wells wherein a flow of actuating liquid is controlled to effect the pumping action, an accumulator including a housing, an actuating liquid suported to float between and within said chambers to maintain a predetermined pressure on the liquid within the liquid chamber dueto the f pressure of the fluid in the pneumatic chamber,l

means to conduct the actuating fluidu from the intermediate reservoir to the pumping system and means for establishing a maximum fluid pressure which may be attained within the intermediate reservoir.

4. A device of the character set forth in claim 3 including means permitting the free entry-of atmospheric air to the intermediate reservoir.

5. In a hydropneumatic pumping system for wells wherein a ilow actuating liquid is controlled to effect the pumping action, an accumulator including a Apneumatic fluid chamber, an actuating liquid chamber spaced therefrom. an intermediate closed reservoir between and connecting said chambers to receive fluid leakage from both of said' chambers, a pressure plunger having longitudinal aligned lengths of different diameters said plunger extending across the intermediate reservoir with one of its ends reciprocally mounted within the actuating liquid chamber and the other of its ends reciprocally mounted within the pneumatic fluid chamber whereby movement of the plunger length of largest diameter from its chamber vinto the intermediate reservoir will increase the pressure of'iluid within said reservoir by iluid displacement, means to conduct the actuating iluid from the intermediate reservoir to the pumping system and means acting to prevent a counterflow of said iluid through the conducting means.

6. In a device of the character set forth in claim 5 including means for limiting the pressure of fluid occurring within the intermediate JAMES F'. ROSS.

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