US2065051A - Piston - Google Patents

Description

Dec. 22, 1936. R. H, CARR ET Al.

PISTON Filed Feb. 19, 1934 Patented bec. z2, 193e PISTON Richard E.

Ogden, Tulsa, Okla.,

Oil. Company, Chicago, Ill.,

Ohio

Carr, Chicago, Ill., and Laurence A.

assignors to The Pure a corporation of Application February 19, 1934, Serial No. 711,970

16 Claims.

Our invention relates generally to pistons of the type provided with a plurality of resilient packing elements and more particularly to pump pistons whose resilient packing elements are sub- 5 jected to different fluid pressures during the y pumping operation.

'This invention may be conveniently applied, for instance, to pump pistons adapted for use in force and lift pumps and the like for pumping 10' fluid from wells.

As herein illustrated, `our invention is shown applied to a lift pump piston or a valve in piston for pumping fluid from deep wells. This piston is sometimes termed in practice as a traveling valve andis adapted to reciprocate within a pump barrel bymeans of sucker rods which extend to the surface of the well and which are connected to a source ofpower from lwhich they derive their motion. The working barrel is suspended inthe well from the lower end of a string Y of tubing as a continuation thereof, and contains a standing lor check valve atits lower end.

Fluid is drawn into the barrel through its check valve and is subsequently displaced by the traveling' valve as the latter descends in the barrel. The iiuid, such as oil, that is being pumped from deep wells generallycarries sand in suspension, which sand acts as an abrasive causing rapid wear of the traveling valve parts, particu-l larly those contacting with'the inner wall of the working barrel.

The conventional type oi traveling valve employs a plurality of packing elements or cups, one of which cups is required to carry the entire 35 load pressure of the iiuid being pumped as the valve moves upwardly. Experience has shown that under these conditions this cup wears rapidly so that it is unable to sustain the load and the next succeeding cup comes into service and 40 is likewise subjected to rapid deterioration.4 Y

It is the principal object of our invention to distribute the load created by the head pressure of the uid being pumped between the cups or packing elements so that one of them is not re- 45 quired to withstand the total pressure until it fails.

To this purpose our invention contemplates the provision of a traveling valve, some of the cups of which are arranged to operate under a pressure differential, thereby distributing the pressure load over several cups which results in lengthening the life of the cups.

We conveniently accomplish this object by distributing the pressure over a plurality of cups 55 and by means of a pressure differential eective (Cl. 10S-225) above and below a cup imposing substantially the same proportions of the load on each of said cups. v

The particular embodiment of the principles of our invention disclosed herein contemplates the regulation of the effective pressuresV above lthe succeeding cups by, the provision of a plulrality of pressure controlled valves which operate in conjunction with the head pressure of the uid to cause a portion of the pressure to be imposed upon each of said cups. When the pressure imposed upon said cups plus the pressure of the corresponding valves equal the total head pressure the valves close, since a state of equilibrium between these pressures has been'reached.

Other novel features and advantages of our invention will hereinafter appear. v

In the accompanying drawing in which Vwe have illustrated for purposes of exemplication but without limiting the claimed invention thereto, certain practical embodimentsof the prin- "ciples of our invention:

Fig. 1 is a side elevation of our traveling valve disposed within the working barrel which is shown in section.

Fig. 2 is a longitudinal section of the valve and barrel.

Fig. 3 is an elevation of the valve barrel.

Fig. 4 is a cross sectional view taken on the line 6 4 of Fig. 2.

Fig. 5 is a cross sectional view taken on the line 5-5 of Fig. l.

Fig. 6 isfa detail in section showing a modified form of the pressure valve structure.

Referring now to the drawing, I represents a cylinder or working barrel in which the traveling valve 2 operates. 3 is the piston barrel which is provided at its upper end with the exterlorly threaded portion d arranged to be secured to the interiorly threaded portion 5 of the perforated crown 6. l is a threaded stud extending upwardly from the crown 6 for securing the traveling valve to the actuating sucker rods (not shown).-

8 represents the slots or perforations in the crown 6 which provide a passageway from the interior thereof to the uted portions 9 in the exterior of the crown and through which the iiuid is permitted to pass from the piston barrel 3 to the working barrel I above the valve structure. o

I0 represents the head of the piston barrel i3 which is faced hexagonally so that a wrench may be applied thereto for assembling the piston barrel with the crown. The body Il of the pis- 55 ton barrel 3 is cylindrical and of an outside diameter less than an inside diameter of the barrel I and the end is arranged to be secured to the lock nut I2 as by means of the threads I3. The head IIl and the lock nut I2 are reduced in diameter so as to provide clearance in the barrel I.

I4 to I9 inclusive represent a series of flexible cups orpacking elements having the central openings 28 for receiving the cylindrical portion II of the piston barrel 3. Beginning with the rst cup and continuing downwardly through the cups I5, I6 and I1, said cups are provided with cup-rings 2|. The lowermost cup or cups, such as I8 and I9, are provided with cup rings 22. Above each of the cup-rings 2| are the annular rings 23.

The cups are formed of flexible material, such as leather, so that their upstanding skirts 24 may be forced outwardly, forming a seal with the inner wall of the working barrel when the pressure is effective thereon. In assembling the top cup I4 is compressed against the shoulder 25 of the head I0 and the under side of this cup is supported from beneath by the ring 23 which is held in place by the rst cup-ring 2 I. The lower end of the first cup ring 2| nts in the cup I5, which in turn is compressed upwardly by the second ring 23, the same arrangement of cuprings and cups being continued downwardly with the lowermost cup I9 being compressed between its cup-ring 22 and the lock nut I2 which is screwed snugly in place. There is preferably a slight clearance between the upper portions of the cup-rings 2| and 22 and the rings 23 and the working barrel I. 'Ihe outside diameter of the lower portions of the cup-rings is reduced in order to fit down into the next succeeding cup. A portion of the perimetral surface of the cuprings is concaved as at 21, which forms the annular spaces 21 with the skirts 24 of the cups and the wall of the barrel I.

In the case of the intermediate cup-rings 2| their upper Walls are internally recessed to form the annular chambers 28 which are enclosed from above by the rings 23. 29 represents ports in the cup-rings 2| connecting the chambers 28 with the spaces 21'.

The cup-rings 22 are not provided with the recesses 28, nor are the rings 23 superimposed thereon. The cup-rings 22 at their upper ends are arranged to directly support the cups above them and the rings 23 are therefore not required.

3|), 3| and 32 are leaf springs secured at one end to the cylindrical portion II of the piston barrel 3 by means of the screws 33, their other ends being arranged to urge the valve balls 34 against the seats 35, closing the passages 36 in the Wall of the piston barrel between the bore of the piston barrel and the recess 28 in which the leaf spring operates. One of said ports 38 registers with each of the chambers 28, which chambers also provide clearance for the leaf spring. The leaf springs are arranged to close their respective valves at predetermined pressures progressively increasing downwardly of the piston barrel. This may be conveniently accomplished by varying the pressure of the individual springs. Thus assuming a uid head pressure of 1200 pounds the spring 30 may be made to urge its corresponding valve ball 34 against its seat 35 with a pressure of 300 pounds, whereas the spring pressures of the springs 3| and 32 are 600 and 900 pounds respectively.

Thus when the pump is operating, elevating fluid such as oil, the total head pressure of `120m pounds will be imposed upon the top cup I4. Now if the spring 30 be arranged to close its valve with a spring force of 300 pounds, the spring 3| arranged to close its valve with a force of 600 pounds, and the spring 33 arranged to close its valve with a force of 900 pounds, the cup I4 would have imposed upon it from below a pressure of 900 pounds, owing to the fact that the ring 23 and the cup ring 2| do not form a seal with the working barrel I. In other words, the net pressure resisting the upward movement of the cup I4 is 300 pounds instead of 1200 pounds. This is due to the fact that the spring 30 will close its valve as soon as the pressure in the chamber 28 and in the space .21 of the cup I5 plus the closing pressure of the leaf spring is equal to the total head pressure in the piston barrel, to wit, 1200 pounds.

Again, if the leaf spring 3| be arranged to close its valve with a pressure of 600 pounds', as soon as the fluid pressure in the corresponding recess 28 and the space 21 of the cup I6 plus the pressure of the spring 3| is equal to the total head pressure of 1200 pounds, the

spring will close its valve, and thus a pressure of 600 pounds will be exerted from below on the cup I5 while the pressure from above on said cup is 900 pounds, therefore, as in the case of the cup I4, imposing a net load pressure of 300 pounds on the cup I5. Likewise if the leaf spring 32 has a spring pressure of 900 pounds an upward pressure of 300 pounds will be exerted on the cup I 6, thus reducing the net pressure eiective from above on said cup to 300 pounds. Moreover, the total pressure imposed on the cup I 1 would likewise be only 300 pounds.

It will thus be seen that each of the cups I4, I5, I6 and I1 carry a load pressure cf 300 pounds and thus the total head pressure of 1200 pounds is equally distributed amongst them.

It is obvious that by providing the proper number of cups, valve closing springs and valves arranged to be closed at the proper relative pressures, the total head pressure of the fluid may be divided into fractional loads over a wide range and be distributed over a plurality of cups.

It will be noted that the cups I8 and I9 are not in this instance provided with pressure valves and the piston barrel and the cup rings 22 are .not provided with passages to admit the fluid into the space as 21 therein. These are reserve cups and will take up the pressure load only when the cup I1 fails. Under ordinary circumstances the pressure imposed on these cups, if any, is due solely to the pressure of such uid that may leak past the superimposed cups.

31 is a traveling check valve at the lower end of the piston barrel 3 which comprises the valve ball 38 and the valve seat 39. The seat 39 is provided with the annular ange 4U arranged to be supported by the shoulder 4I of the lock nut I2. As the traveling valve 2 descends into the fluid in the working barrel the valve ball 38 is caused to rise, admitting fluid into the piston barrel 3, and when the traveling valve reaches the end of its stroke and reverses in direction the fluid forces the ball 38 against its seat 39, preventing any fluid from escaping therefrom. The fluid is admitted to the traveling valve 2 through the openings I 2' in the lower portion of the lock nut I2.

Referring to the modification as shown in Fig. 6, we have substituted for the pressure valve leaf spring a helical spring 42. This spring is contained in a bushing 43 whose inner end is contracted to form a seat for the valve ball 34'. The spring 42 isadjusted to close the valve at the desired pressure by means of the threaded plug 44 which is adjustably screwed in the outer threaded bore of the bushing 43.

While we have illustrated and described our invention particularly in reference to well pumps. it will be understood that changes may be made in the forms disclosed, without departing from the spirit of my invention and that certainfeatures may sometimes be used to advantage without a'corresponding use of other features.

We claim:-

1. In a piston arranged for relative reciprocation in the bore of a cylinder, the combination of a hollow pistonbody open at one end to iiuid pressure imposed on the piston, a plurality of packing elements mounted in spaced relation in series on the piston, passageways connecting the space between the packing elements and the interior of the piston, and means for controlling the passageways for dividing the total uid pressure between the two packing elements.

2. In a pump piston, the combination with a cylinder and a piston barrel arranged to reciprocate therein'and having a check valve in one end thereof, of a plurality of cups mounted in series on said piston barrel and arranged to collectively effect a iiuid actuated seal-between the piston ba'rrel and the cylinder, andpressure responsive means including means operable against the total uid pressure for distributing the total fluid pressure imposed on said piston barrel proportionately among said cups. 3. In a pump piston, the combination with a cylinder member and a piston barrel member arranged to reciprocate therein and having a check valve in one end thereof, of a plurality of cups mounted in series on said piston barrel and arranged to collectively eiect a uid actuated seal between the members, and pressure responsive means including means operable against the total iiuid pressure for regulating the pressures eiective on an individual cup from above and below the latter whereby the total iiuid head pressure imposed on the valve barrel is distributed proportionately among said cups.

4. In a pump piston, the combination with a cylinder and a piston barrel arranged to reciprocate therein and having an axial bore provided with a check valve, of a plurality of cups mounted in series on said piston barrel and arranged to collectively eiect a uid actuated seal between the piston and the cylinder with intervening annular spaces between the cups, and pressure responsive means including means operable against the total' iluid pressure for regulating the pressures effective on the individual cup from above and below the latter whereby the total iiuid head pressure imposed on the valve barrel is distributed proportionately among said cups.

5. Ina pump piston, the combination with a working barrel and a. piston barrel arranged to reciprocate therein and having an axial bore provided with a check valve, of a plurality of cups mounted in series on said valve barrel and arranged to collectively effect a fluid actuated seal between the barrels, with intervening annular spaces between the cups, and means comprising openings arranged to admit the fluid pressure to said spaces and pressure-control valves for said openings whereby to distribute the total fluid head pressure proportionately among Vsaid. cups.

6. In a pump piston, thecombination with a working barrel and a piston barrel arranged to reciprocate therein and having an axial bore providedwith a check valve, of -a plurality ofcup mounted in series on said piston barrel and ar. ranged to collectively effect a iiuid actuated seal between the barrels, with intervening annular spaces between the cups, and means comprising openings arranged to admit the fluid pressure to said spaces and pressure-control valves for said openings, said valves downwardly of said piston barrel being of progressively greater head pressure-reducing power whereby the total fluid head pressure is distributed proportionately among said cups.

7. In a pump piston, thecombination with a working barrel' and a piston barrel arranged to reciprocate therein and having an axial bore provided with a check valve, of a plurality of cups mounted in series on said piston barrel and arranged to collectively eiiect a uid actuated seal between the barrels, with intervening annular spaces between the cups, and means comprising openings arranged to admit the iiuid pressuretov said spaces and spring-closed valves for said openings, the power to close said valves progressively increasing downwardly oi' said valve barrel, o

whereby the total fluid head pressure is distributed proportionately among said cups.

8. In a traveling valve, the combination with a working barrel and a piston barrel working therein and having an axial bore provided with a check valve, of a plurality of,cups mounted in series on the piston barrel and arranged to collectively eiect a uid actuated seal between the barrels, openings in the wall of the piston barrel to admit the uid pressure between said cups, and pressure-control valves for said openings and arranged to proportionately distribute the total iiuid head pressure imposed on the piston barrel among said cups. f

9. Ina traveling valve, the combination with a working barrel and a piston barrel working therein and having an axial bore provided with a check valve, of a plurality of cups mounted in series on the piston barrel and arranged to collectively eiect a ilnid actuated seal between the barrels, openings in the wall of the piston barrel to admit the iiuid pressure between said cups, and presrsure-control valvesfor said openings, said valves having progressively increasing closing power downwardly of said piston barrel whereby to proportionately distribute the total iiuid pressure imposed on said piston barrel among the cups.

10. In a piston arranged for relative reciprocation in the bore of a cylinder, the combination of a plurality of annular elements mounted on the piston to effect a uld actuated seal between the piston and the bore of the cylinder, and pressure responsive means including means operable against the total :duid pressure for dividing thel total uid pressure imposed on the piston among the said elements.

1l. In a piston arranged for relative reciprocation in the bore of a cylinder, the combination of a plurality of annular elements mounted on the pistonto effect a fluid actuated seal between the piston and the bore ofthe cylinder, and means for distributing the' total fluid pressure on the piston between the elements, each element being subjected to an aliquot part of the said total pressure. l

12. In a piston arranged for relative reciprocation in the bore of a cylinder, the combination of a plurality of annular packing elements mounted in series on the piston to collectively eiect a the total fluid pressure on the piston betwee the packing elements, each packing element being subjected to an aliquot part of the said total pressure.

13. In a piston arranged for relative reciprocation in the bore of a cylinder,' the combination of a pair of annular packing elements mounted in spaced relation in series on the piston to collectively effect a iuid actuated seal, a passageway connecting the space between the packing elements and the end of the piston exposed tothe uid pressure, and means for controlling the passageway for distributing the total fluid pressure on thepiston between the packing elements, each packing element being subjected to an aliquot part of the said total pressure. l

14. In a piston arranged for relative reciprocation in the bore of a cylinder, the combination of a hollow piston body open at one end tc uld pressure imposed on the piston, a plurality of packing elements mounted in spaced relation in series on the piston, passageways connecting the space between the packing elements and the interior of the piston, and means for controlling the passageways for distributing the total fluid pressure on the piston between the packing elements, each packing element being subjected to under pressure effective against one end thereof.

the combination of a seriesof fluid-actuated annular packings carried by said piston, communieating means between the packings and the pressure end of said piston and pressure responsive means in said communicating means including means operable against the total :duid pressure for dividing the total duid pressure imposed on the piston among the said packings.

RICHARD H. CARR. LAURENCE A. OGDEN.

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