US2344786A - Antipound pump pressure equalizer - Google Patents

Description

March 1944- E. w. PATTERSON ET AL 2,344,786

ANTIPOUND PUMP PRESSURE EQUALIZER 3 Sheets-Sheet l @al'lffpattel'son/ esley l altenswz/ TTORNEY INVENTORS fig -. @daaaaaaaa Filed March 24, 1942 March E. w. PATTERSON ET AL 2,344,786

ANTIPOUND PUMP PRESSURE EQUALIZER Filed March 24, 1942 3 Sheets-Sheet 2 INVENTORS' I dl'lx'hzifemon/ BY l/-s' L. Mtersavz/ 451 i .36 36 ATTO R N EY Patented Mar. 21, 1944 ANTIPOUND PUMP PRESSURE EQUALIZEB Edgar W. Patterson. Downey, and Wesley L.

. Patterson, Long Beach, Calif.

Application March 24, 1942, Serial No. 436,004

Claims.

The present invention relates generally to fluid pumping devices of the rod actuated type employed in deep wells, more especially oil wells, wherein the working chamber is loaded during each suction stroke with a mixture of oil and gas, or in other words a substantially incompressible liquid and a highly compressible fluid, and wherein the production column into which the pump discharges, imposes a. high pressure outside the pump tending to hold the discharge or traveling valve against opening.

The present invention is, more particularly, a pressure regulator for deep well rod pumps of the above type, having for its primary object the provision of a practical and efllcient means for eliminating the hammer or pound commonly incident to their operation and occurring during the down or discharge strokes.

It is commonly known that the objectionable hammer or pound in deep well rod pumps is due to the fact that the pump chamber is loaded during each suction or upstroke with the above mentioned highly compressible fluid and a substantially incompressible liquid, and to the further fact that the very high pressure of the production column above the pump throughout the length of the production tubing not only tends to prevent opening of the traveling valve but constantly adds acceleration to the down stroke until the traveling valve opens.

It is also commonly known that the rods of such pumps are actuated by surface equipment including a pumping unit and a counter-balancing device, and that the hammer or pound of the pump not i only imposes unnecessarily severe stresses and strains on the rods and the producthat it occurs just prior to the actual opening of the traveling valve, during the intermediate accelerated travel of the working member on its down or discharge stroke when pressure within the puinp chamber equals outside pressure of the production column and the latter pressure is no longer eifective as a downward urge against the working member of the pump.

Every pump of the above character includes a working or pump chamber between a lower standing valve and an upper traveling valve, and the present invention proposes, and has for its obiect to provide, means whereby during each down or discharge stroke, and when substantial pres- ,sure has been built up therein, but before said internal pressure reaches a point equal to outside or production column pressure, the pump chamher will be placed in communication with the outside pressure for equalization of these pressures,

and such communication then cut of! prior to the time the traveling valve would, in normal pump operation, open to permit discharge from the pump chamber.

Various problems must be met in any practical arrangement which will accomplish the foregoing, and to meet these problems the invention has as its broad concept the provision of a displaceable member in the pump chamber and between the standing and traveling valves, which is displaced on its effective stroke by the pressure in said chamber as said pressure increases; the creation of'a low pressure area in advance of said displaceable member so that there will be either no retarding effect against its movement or a regulated retarding thereof; means positionable by and during the effective displacement of said member to place the pump chamber in communication with the high pressure area of the production column for equalization of inside and outside pressures at a time substantially in advance of reaching equal pressures in normal pump operation; means whereby following equalization of high pressures within and without the pump chamber, there is effected an equalization of pressure between the pump chamber and the low pressure area to permitof return of the displaceable member to normal position; and means for exhausting high pressure from the normally low pressure area into the pump chamber during the succeeding up or suction stroke of the working member of the pump when the pump chamber is at low pressure, in order to restore low pressure within the low pressure area in advance of the construction and adapted to lasting eifectiveness.

In the accompanying drawings, illustrating the suggested forms,

Figure 1 is a'vertical sectional view through a rod pump in a well, showing the application thereto of a form 01' the present invention in which provis on is made for direct control of the travaiins valve.

Figure 2 is an enlarged vertical sectional view through that portion of Figure 1 which includes the parts proposed by this invention located between 2 and 2 of Figure l and exclusive of the normally operating pump parts below line 2 of the latter figure. Figure 3 is a view, partly in elevation and'partly in section, illustrating the manner of operation of the invention, showing the parts in position after initial displacement of the displaceable member but prior to unseating of the traveling valve.

Figure 4 is a view similar to Figure 3 showing the parts in position after final displacement of the displaceable member, with the traveling valve unseated and the isolated lower pressure area in communication with the pump chamber.

. Figure 5 is a side view, partly broken away and in section, showing the displaceable member and its attached parts, at the position, during their downward or return movement, at which the traveling valve is free to take its seat while the isolated pressure area or chamber is still in pressure equalizing communication with the pump chamber.

Figure 6 is a view partly in elevation and partly in section, illustrating a slightly modified form in which the traveling valve seat is shifted instead of the traveling valve itself.

Figure '7 is another view partly in elevation and partly in section, illustrating a further structurally modified form in which provision is made for equalization of pressure within and without the pump chamber entirely apart from the travel- Figure 14 is a similar view taken on line l4-l4 of Figure '7.

. Figure 15 is a similar view taken on line i5-i5 of Figure 6.

Figures 16 and 17 are similar views taken respectively on lines i6-l6 and i'I-i'l of Figure 'l; and

Figures 18 and 19 are other similar views taken respectively on lines i8i8 of Figure 3 and i9-l9 of Figure 4.

Referring now to Figure 1, there is shown the casing 25 within a well bore 26. Parts of a conventional well pump are shown within production tubing 21 and, as the most commonly used working barrel type of pump has been selected for illustration, there is shown at the lower portion of the figure a hollow upstanding stationary plunger 28 inserted at its lower end in a seat 29 within tubing 21 and provided at its upper end with astanding valve 30.

The working member of this pump is a traveling barrel 3i which is moved up and down in its closely fitting relation around the plunger 28, by means of the rods 32 shown connected to the upper traveling valve cage 33.

This cage 33, which carries the traveling valve 34 and its seat 35, is, in the ordinary pump assembly, threaded on a coupling member 36 in threaded connection with the upper end of the working barrel 3i. For the purposes of the present invention, however, the cage 33 and its parts are removed from the working barrel coupling 3B, and are shown above the line 2 in Figure l. The ordinary pump assembly, excepting the traveling valve cage 33, is shown in this figure below the line 2.

The present invention involves an assembly, shown between the lines 2 and 2 of Figure l and includes a housing preferably in the form of a barrel 3! which is threaded at its lower end on the working barrel coupling 36 and is preferably of the same outside diameter of the working barre] 3!. Thus, by removing the traveling valve cage 33 from the working barrel 3i of the ordinary pump, the barrel 3! of the present invention may be connected, by reason of the coupling 36, to the upper end of the said working barrel 3i.

The housing or barrel 3! has at its upper end a coupling 38 to which the traveling valve cage 33 is then threadedly connected in the same manner it was previously connected to the working barrel coupling 36. Thus, for the purposes of installation of the present invention, its housing or barrel 31 is merely to be installed between the working valves of the ordinary deep well pump of the traveling barrel type.

The housing or barrel 3'! of the present invention houses all of the parts necessary to achieve its purposes, and the coupling 38 at the upper end of the barrel may be in the nature of a supporting head for a hollow mandrel 39 depending into the barrel 3'! in'spaced relation thereto and terminating at its lower end substantially above the lower end of the barrel 31. At an intermediate point thereof, substantially above its lower end, the mandrel 39 has an external annular groove and an annular series of openings 40 through its wall around the bottom of its groove. as better seen in Figures 2 and 9.

As also best seen in Figure 2, the mandrel 39 is of substantially reduced diameter with respect to the barrel 3! and has a sliding, pressure-tight fit at its lower end portion within the axial bore 4| of a pressure actuated piston 42 which, in its lower inactive position, seats on the upper inner end of the'coupling 36. This piston 42 has exteriorly thereof a sliding pressure-tight fit within the barrel 3! and is provided with an upper externally reduced portion 43 having an externally opening wall aperture 44 which communicates at its inner end with the upper end of a lengthwise pressure channel 45 in the piston wall. The channel 45 opens at its lower end into a counterbore, forming an annular shoulder against which an upwardly seating pressure relief valve 46 is seated by means of a spring 41 compressed at predetermined tension between the valve and a lower plug member 48 threaded into the counterbore. It will also be noted that ports 49 are grouped around the threaded plug member 48 and open through the lower face of the piston 42 as well as within the counterbore below valve 46.

The piston 42 has lengthwise flow channels 50 through its lower pressure receiving surface and communicating with its bore 4| at points substantially below the lower end of mandrel 39 and, as plainly seen in Figures 2 and 12, these channels are grouped around its axial area into which is threaded the lower end of a fixed upstanding stem 5i. The stem5l rises through the mandrel 39 and terminates at a point spaced a predetermined distance below the traveling valve 34 when the piston 42 is in lowermost inactive position. The upper portion of stem 5| may be effectively guided through a bearing member 52 assures seated within the mandrel head or coupling member 38 and provided with flow channels 53 around its bearing, as in Figures 2 and 8.

Threaded on the upper reduced skirt 3 of the piston 42 is the lower end of a cylindrical valve shell 54 which has a constricted or internally flanged upper end 55 and forms between the same and the upper face of the reduced portion 43 of piston 42 an annular space or valve compartment in which a lengthwise valve sleeve 56 is axially shiftable and has a snug, sliding fit on the mandrel 39 in a position to cover and totally close 01! the previously mentioned wall openings 40 01' the latter. The valve sleeve 56 has, intermediate its ends, an annular series of openings 51 through its wall along the base of an internal annular groove, as in Figures 2 and 10, to be moved into and out of communicating registry with the mandrel openings 40 as the sleeve 58 is shifted upwardly by the piston skirt #3, and downwardly by the shell flange 55. The valve sleeve 55 is of substantially less length than the compartment in which it is dispose It will-be noted that valve shell 54 has an annular series of openings 58 afiording communication between the sleeve valve compartment 59 and the interior of the barrel 31, especially the pressure chamber 50 formed between said barrel and the mandrel-39, which chamber 50 is isolated from the working chamber of the pump; or, in other words, the fluid space therein between the standing and traveling valves, when the. piston 42 and sleeve valve 56 are in lower position with openings to and 51 out of communicating registry.

A coil spring 8| in the isolated pressure chamber 50, around the mandrel 39, has abutment at its upper and against the lower surface of the mandrel head or coupling 36, and bears at its lower end on the flanged upper end 55 of valve shell 54 to thus tend to force the piston 42 to its lowermost position at the end of each downstroke of the pump rod and each discharge stroke of the pump. In this position the traveling valve is seated by the head pressure of the column of liquid and fluid in the tubing 21 above the pump representing, for example, apressure of two thousand pounds per square inch effective to hold the traveling valve 34 in closed position during the subsequent upstroke or suction stroke.

At the start of this stroke the isolated pressure chamber 60 may freely exhaust any, pressure therein through pressure outlet valve 46 into the low pressure area within the pump, which maintains throughout the upstroke as well fluid is drawn upwardly through the standing valve 80 to more or less flll the working chamber of the pump, or that space between the standing valve 30 and traveling valve 34, but not the isolated pressure chamber 50, to which inflow of fluid is cut of! by the sleeve valve 55 in its lowermost position.

At the end of the suction stroke, the rods and working member of the pump start downwardly on the discharge, stroke, with pressure in the pump substantially at zero as, compared with the above high pressure of the head of fluid in the production tubing above the pump which holds the traveling valve on its seat in ordinary pumping operation until pressure within the pump equals tubing pressure. It is at this point in normal pump operation that the fluid hammer or pound occurs by reason of the fact that downward movement of the working member of the pump suddenly loses a very material factor entering into its accelerated downward movement, namely, the head pressure of the column of fluid in the production column. Until this point is reached the working member of the pump has been compressing, during ordinary pump operation, the compressible fluid in the working chamber. When internal or pump pressure reaches external or tubing pressure, and

the working member loses the downwardly accelerating influence of the tubing pressure, the pound or hammer occurs as the workingmember comes into sudden contact with the solid liquid in the pump chamber, minus previous acceleration of tubing pressure represented by the fluid head therein, at or about the time when compression of the compressible portion of fluid in the working space of the pump between the standing and traveling valves has reached a maximum and the working member is against a substantially incompressible body composed either entirely of incompressible liquid or such liquid and already highly compressed fluid or gas.

Thus in the ordinary pump subject to the undesirable pound, the traveling valve does not open for discharge of fluid therefrom into the production column until pump pressure substantially equals production column pressure.

In deep wells this means a pump pressure 'of as much as two thousand pounds per square inch and generally results in pounding which not only places serious working strains on the rods and production tubing, but racking stresses on the surface equipment.

With the present invention, inner piston member 42 starts to move upwardly, or to recede into the isolated pressure chamber 60, as pressure within .the pump chamber increases during downward movement of the working member. by reason of its downwardly facing net surface area. The isolated chamber 50 being then at low pressure, there remains nothing to oppose such recession of the piston 42 except the spring 8|, together with such low pressure as may be retained in chamber 50, the effective total of which thus controls the amount of pressure which must be built up within the pump to bring about fully effective receding stroke of the piston.

Bearing in mind that to open the working chamber of the pump to production tubing pressure at a time when the former is at low pressure would cause such an inrush of high pressure liq uid as to cut away the walls of any opening however formed therebetween, the spring 5|, plus controlled retained pressure within the isolated chamber 80, forms a means of preventing full eilgctive stroke of the piston until such a pressure has been built up within the pump as to permit control of the velocity of incoming tubing pressure liquid in order to avoid undesirable cutting or wear of the parts.

During the initial recession of the piston 42 as pump pressure builds up, it moves gradually upwardly until the upper end of its reduced skirt 43 strikes the lower end of the sleeve valve 58, as represented by the relative position of the parts shown in Figure 3. At this time, the upper end or the stem Si is about to engage the traveling valve 34 then on its seat 35.

In the further upward-movement of piston 42, during which pressure is further built up within the working chamber of the pump to a point (say fifteen hundred pounds) permitting safe transfer of high pressure liquid or the production column into the working chamber, the stem II pushes the traveling valve 34 upwardly off its seat, as seen in Figure 4, and at approximately the same time the sleeve valve 50 is elevated to a position where its openings or ports 51 are more or less in registry with the openings or ports 40 of the mandrel 39. Thus, substantially before pressure has been built up within the pump to the pressure of the production column, the unseating oi the traveling valve 34 in the above manner, permits these inside and outside pressures to equalize and thus'permits the \working member of the pump to complete its downward discharge stroke without encountering any sudden shock creating a pound.

Thus, also, at or immediately following equalization of inside and outside pressures, the-regis tering position of sleeve valve 56 permits of equalaccomplished byshiiting the seat member of said valve from a normally seated position, rather than the valve. member, as seen in Figureso, 13 and 15, and by arranging for the registration and non-registration of lateral ports, as shown in Figures 7, 14, 16 and 47, to thus accomplish the desired end without touching either the traveling valve or its seat.

In Figures -6, 13 and 15 the seat member I! of the traveling valve 34, is shown removably seated ona seat 85 at the upper inner end of the mandrel head or coupling 36, with a dependization of pressure as between the pump chamber I the working member of the pump, so that the traveling valve can seat naturally-underspro duction column pressure as the end of the discharge stroke is reached and the period of low pump pressure is resumed.

As the piston starts downwardly with balanced pressures, under spring actuation, it moves to engage the flanged upper end 55 of shell 54 with the upper end of valve sleeve 55 as seen in Figure 5, and subsequently pushes said valve sleeve downwardly to its lowermost losed position shown in Figure 2, whereby to again isolate the pressure chamber 60 with respect to the pump chamber.

When low pressure is again established in the pump after finish of the discharge stroke, the

pressure previously established in chamber 60,

exhausts through the pressure relief valve 46 into the low pressure area within the pump so that the parts are thus completely restored and ready for the next suction stroke.

It will be appreciated from the foregoing that it is the intention of the invention to so proportion the parts and their relative movements as to positively open the working chamber of the pump to the production column for equalization of their pressures at a point wherein pump pressure has increased in such relation to production pressure as to permit of transfer of higher production column pressure into the pump chamber without danger of'cutting or undue wear of the walls of the transfer channel due to high velocity of liquid, and also at a time sufficiently in advance of normal build up of pressure in the pump chambet to production column pressure, to avoid the fluid hammer or pound occurring at this time in ordinary pumps.

In the construction shown and described for the above purposes, in connection with Figures 1 to 5, 8 to 12, and 18 and 19, inclusive, equalization of pressures within and without the pump chamber is predicated upon the actual lifting of the traveling valve 34 from its seat at the proper time, but it is obvious the same result may be ing skirt It provided with wall openings l! in the bottom of an external anmilar groove so that when the seat member .35 is shifted upwardly of! its seat, pressure may flow downwardly into the pump chamber. In this instance, piston 42' has an upright hollow stem 68 which, upon rise of the piston engages the skirt 66 for upward shifting of seat member 35*, and the mandrel 39' has a sliding fit around the hollow stem 68 and carries at its lower end a stationary valve shell 54" and a sleeve valve 56 which moves within this shell and snugly embraces the stem 68.

The hollow stem 68 has ports or openings 69 which are, respectively, moved into and out of registry with I the ports 51'- of the snugly surrounding val e sleeve 56, the latter being shifted with respect to the stem upon engagement with the lower end of mandrel 39 and the lower flanged end 55" of shell 54. Spring BI is, in this instance, between the piston 42 and shell 54 and thus many of the corresponding parts of this form of structure and that previously described are relatively reversed. However, it will be plain that piston 42' of this form moves upwardly and in such movement the hollow stem 68 is shifted to bring about precisely the same operation and results as previously described, except that stem 68 acts to unseat the valve seat member rather than to unseat the valve itself.

In this form the isolated pressure chamber is communicated with the pump chamber through the valve sleeve 56* and, it is to be understood, exhausts into the pump chamber at low pressure through a relief valve in connection with the piston 42* (see Figure 15) in the same manner as described in connection with the first outlined structure. The ports for the relief valve appear at 44 and 45 in Figure 6.

According to the form of construction shown in Figures 7:14, 16 and 17, neither the traveling valve 34' nor its seat member 3.": are involved in the equalization of pressures within and without the pump chamber as contemplated by this invention. The piston 42 having a pressure relief valve (see ports 44 and 45 in Figures '7 and 17) to exhaust the isolated pressure chamber 60" into the pump chamber at low pressure, carries a rising hollow stem 10, and either this stem or the piston 42'', or both, may have ports II and 12 to respectively register with wall ports 13 and 14 of the mandrel head 38 and barrel 31 when the piston 42' has been shifted upwardly to the desired point. The mandrel 39' carries at its lower end stationary valve shell 54*, and sleeve valve 56' embraces the piston stem 10 and is shifted with respect to the latter when it engages the end of the mandrel and the flanged end 55' of the shell, to thus control equalization of pressure as between the pump chamber and the isolated pressure chamber 60*, through ports 15 of the stem and ports 51' of the sleeve valve.

The piston controlling spring is shown at 6| in the isolated pressure chamber 60 between assavae mu be desired.

It is plain that in each of the described struc- 1 tural forms, of which there may be others, a

piston member is displaced as the pressure in the pump chamber or the space between the pump valves, increases, and that this displacement is brought about by such pressure. Inaddition, each form of structure involves the creation of a low pressure area in advance of the piston in its displacing movement so there will be no, or substantially low, fluid pressure resistance to its movement and control of such movement left to predetermined and readily regulated spring pressure, as well as means positionable during displacing movement of the piston for affecting an equalization of pressure between the pump chamber and the production column substantially in advance of normal rise of pump pressure to equal production column pressure. Still further, each structure includes means whereby immediately following equalization of pressures as between the pump chamber and the production column, pressures are also equalized as between the pump chamber and the low pressure area to permit the piston member to be returned to a position of rest and means to then permit of the exhausting or unloading of pressure within the isolated pressure area into the pump chamber when the latter is again at low pressure, to thus restore said area to low pressure for the next pump discharging operation.

Having thus fully set forth the invention, what we claim is:

1. An anti-pounding device for use with a deep well pump discharging into a high pressure production column, and having a working chamber between standing and traveling valves, said device including means exposed at one side to working chamber pressure and yieldable in one direction in accordance with rising pressure in said working chamber during each discharge stroke of the pump, means forming a chamber normally isolated from rising'pressure, in said working chamber and to which said yieldable means is exposed at its opposite side, means positionable by said yieldable means in the course of its yielding movement for opening the working chamber of the pump into pressure equalizing communication with the production column independent of the traveling valve of the pump, means for returning said yieldable means to inactive position subsequent to said pressure equalization, and means controlled by said yielding means in the yielding and return movements thereof for respectively establishing and cutting oil. pressure communication between the working chamber and the said isolated chamber.

2. An anti-pounding device for use with a deep well pump discharging into a high pressure production column, and having a working chamber between standing and traveling valves, said device including means exposed at one side to working chamber pressure and yieldable in one direction in accordance with rising pressure in said working chamber during each discharge stroke of the pump, means forming a chamber normally isolated from rising pressure in said working chamber and to which said yieldable means is exposed at its opposite side having a valved pressure outlet into the working chamber,

means positionable by said yieldable means in the course of its yielding movement for opening the working chamber of the pump into pressure equalizing communication with the production column independent or the traveling valve of the pump, means for returning said yieldable means to inactive position subsequent to said pressure equalization, and means controlled by said yielding means in the yielding and return movements thereof for respectively establishing and cutting of! pressure communication between the working chamber and the said isolated chamber.

8. In an anti-pound device, a barrel. a piston slidably interfltting said barrel, spring means normally holding said piston seated within the lower end of the barrel, said piston having vertical pressure channels therethrough, a hollow stem carried by and upstanding from said piston, said stem and said piston cooperating with portions of the barrel to form a chamber therebetween normally isolated from the interior of the stem and having a valved pressure outlet, said barrel and said stem having wall openings therethrough for registry upon upward movement of said piston and its stem, and valved means controlled by the stem respectively placing the same in communication with, and closing the same to,

the said isolated chamber during upward and,

downward movements of-the piston and stem.

4. In an anti-pound device. a tubular housing member, a pressure elevated piston assembly including a piston member and an upstanding tubular stem slidable in said housing member and forming in the latter a chamber around the stem, having a valved pressure outlet, spring means for urging said assembly to lowermost position, said assembly and said, housing member having wall openings registering in the upper position of the assembly, said stem having wall ports openin into said chamber, and a valve controlled by said assembly to respectively open and close said stem ports during upward and downward movements of the assembly.

5. In an anti-pound device, a barrel, a piston slldably interfitting said barrel, spring means normally holding said piston seated within the lower end of the barrel, said piston having vertical pressure channels thefethrough, a hollow stem carried by and upstanding from said piston, said stem and said piston cooperating with portions of the barrel to form a chamber therebetween normally isolated from the interior of the stem and having a valved pressure outlet, said barrel and said piston having wall openings therethrough for registry upon upward movement of said piston and its stem, and valved means controlled -by the stem respectively placing the same in communication with, and closing the same to, the said isolated chamber during upward and downward movements of the piston and stem.

6. In an anti-pound device, a tubular housing, a vertically displaceable piston having fluid channels therethrough and slidably interfitting said housing, a hollow stem rising from said piston and open to said fluid channels, the piston and its stem cooperating to form a chamber between the stem and housing having a valve controlled pressure outlet, an outlet valve at the upper end of the housing, a seat member for said valve having a vertically displaceable seat at the upper end of the housing for displacement by said stem during upward movement of the piston, said stem having a wall port opening into said chamber, means controlled by said stem in its upward and downward movements for respectively opening and urging said piston and stem to lowermost position in said housing.

'7. In an anti-pound device, a barrel, a vertically displaceable piston in said barrel having an upright hollow stem and channels there'through opening into the lower end of the stem, an outlet valve adjacent to the upper end or the barrel including a valve member anda vertically displaceable seat member for engagement by said stem during upward movement of the piston, said piston and its stem cooperating with the barrel to form a chamber therebetween, the stem having wall ports opening into said chamber, and valve means controlled by said stem and respectively opening and closing said stem ports during' upward and downward movements of the stem.

8. In an anti-pound device, a barrel, a vertically displaceable piston slidably interfltting said barrel, having flow channels therethrough 'and an upstanding skirt portion, a reduced solid stem rising from said piston, an outlet valve seated adjacent to the upper end of vthe barrel and displaceable by said stem upon upward movement of the piston, a hollow mandrel depending within, and spaced from the barrel, having its lower end slidably interfitting the skirt portion of the piston, said piston, mandrel and barrel forming a chamber between the mandrel and barrel isolated from the interior of the mandrel and having a valved pressure outlet through the piston, said mandrel having wall ports for communication with said chamber, and a valve controlled by the piston and respectively opening and closing said ports during upward and downward movements of the piston.

' 9. In combination with a deep well pump discharging into a high pressure production. column and including a working chamber between standing and traveling valves, means forming a low pressure area isolated from saidworking chamber during rise of pressure in said chamber incident to each discharge stroke of the pump, a displaceable piston member exposed at one side to working chamber pressure and at its opposite side to said low pressure area, means controlled by said piston member in its pressure actuated displacement for opening the working chamber into communication with the production column at a time prior to normal rise of pressure in said chamber equal to production column pressure,-

means tending to return the piston member, means controlled by the piston member respectively establishing and cutting 03 communication between the working chamber and said isolated area during displacing and return movements of the piston member, and valved means for exhausting pressure from said isolated area after return movement of the piston member.

10. In combinationwith a deep well pump discharging into a high pressure production column and including a working chamber between standing and traveling valves, movable means actuated by rising pump-created pressure in said chamber during each discharge stroke of the pump and eiIective to place said chamber in communication with the production column before normal rise of pressure in said chamber reaches production column pressure, and means effective to return said movable means to inactive position subsequent to such equalization of internal and external pressures.

11. In combination with a deep well pump discharging into a high pressure production column and including a working chamber between standclosing said port, and spring means normallying and traveling valves, means. actuated by pump-created pressure in the working chamber and active during the latter portion of each discharge stroke of the pump for equalizing-pressures within the working chamber and the pro duction column prior to normal rise of pump pressure to production column pressure, and spring means returning said first named means to inactive position subsequent to such equalization of pressures.

12. In combination with a deep @9615 pump discharging into a high pressure production column and including a working chamber between standing and traveling valves, a member displaceable by pump-created pressure rising in said working chamber during each discharge stroke of the pump, means actuated by said member and eilective to open communication between the pump chamber and the production column prior to normal rise of fluid pressure in said chamber to equal production column pressure, and spring means resisting displacement of said member and for causing its return movement.

13. In combination with a deep well pump discharging into an area of high pressure and including a working chamber between standing and traveling valves, in which chamber pumpcreated pressure must normally build up during each discharge stroke to equal external high pressure before opening of the traveling valve, means movable in one direction under normally rising pump-created pressure in said working chamber during each discharge stroke, spring means resisting pressure movement of said first named means and causing return movement thereof, and means positionable in the course of movement of said first named means to place the working chamber in communication with external pressure, for pressure equalization therebetween, prior to normal rise of working chamber pressure suflicient to open the traveling valve, and substantially before completion of the discharge stroke.

14. In combination with a deep well pump discharging into an area of high pressure and including a working chamber between standing and traveling valves, in which chamber pump-created pressure must normally build up during each discharge stroke to equal external high pressure before opening of the traveling valve, means displaceable by, and in accordance with, normal rise of pump-created pressure in the working chamber during each discharge stroke, spring means resisting displacement of said first named means and effective to subsequently cause return movement thereof, and means positionable by said first named means during the latter portion of said displacement, to open communication between the working chamber and external high pressure prior to normal opening of the traveling valve and before completion of the discharge stroke.

15. In combination with a deep well pump discharging into an area of high pressure and including a working,chamber between standing and traveling valves, in which chamber pressure must normally build up during each discharge stroke to equal external high pressure before opening of the traveling valve, means exposed to, and'displaceable by, rising pressure in the pump chamber during each discharge stroke of the pump, means forming a chamber isolated from rising pressure in the pump chamber and constituting therein an area of low pressure opposin displacement of said displaceable means, means positionable by said dispiaceable means during rise of pressure in the pump chamber for placing the pump chamber in open communication with the external area of high pressure prior to normal opening of the traveling valve, means for subsequently returning said displaceable means to normal position, and valved means forming a pressure discharge-from said isolated chamber and opening into the working chamber when the latter is at low pressure during each 6 suction stroke of the pump.

EDGAR W. PATTERSON. WESLEY L. PATTERSON.

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