US2404524A - Pumping mechanism - Google Patents

Description

J. NORTON PUMPING MECHANISM July 23, 1946.

Filed April 12,1945 4 Sheets-Sht 5 sunn 23, 1946; J, R. NQRTQN 523491145 4 PUMPING MECHANISM Filed April 12, i945 4 Sheets-Sheet 4 Patented July 23, 1946 PUMPING MECHANISM Joseph R. Norton, Tulsa, Okla., assignor to W. C.

Norris, Manufacturer,

Okla.

Incorporated, Tulsa,

Application April 12, 1945, Serial No. 587,885

9 Claims. 7 1

This invention'relates to new and useful improvements in pumping mechanisms.

As is well-known, certain strata of the earth's formation are pervious, while other overlying or underlying strata are impervious and these strata are not planular, but are frequently warped or folded. Since crude oil is lighter than natural ground water, it seeksan elevation above the Water and, therefore, crude oil is usually found in the uppermost portions or domes of the folded strata or, geologically, the anticlines. 'An impervious strata, known as cap rock, generally overlies the anticlines so as to prevent upward migration of the oil which consequently accumulates in said anticlines; Due to the oil being supported in this position by the pressure of the ground water and the cap rock preventing migration of'said oil,the latter is necessarily'under considerable pressure. Therefore, upon a well bore being drilled through the cap rock, there is a sudden release of pressure which causes the oil to flow upwardly through the Well bore to the surface, the first cycle of most wells. However, as the pressure declines, the natural flow ceases and the oil must be lifted artificially to the surface. Crude oil, under the above conditions, contains all phases from light, volatile gases to heavy hydrocarbons and it is necessary to control the pressure exerted against the exposed surface of the producing strata, because a pressure too low will accelerate the migration of the oil to a velocity suflioient to carry sand and silt from the pervious strata and thereby clog or sand up the well bore. Also, encroachment of the ground water into the well bore is permitted, since said water will flow from a high pressure region to a region of low or diminished pressure. In addition, as the pressure on the formation or strata drops, the gases and/or lighter hydrocarbons disassociate or escape from the heavier hydrocarbons of the crude oil and evolve in a gaseous condition. The evolution of these gaseous constituents not only reduces the quality of the remaining oil but also tends to gas lock the pumps employed to lift said oil.

With conventional rod pumps, the reciprocal motion of the rod is principally harmonic and transmits to the pump plunger or piston a reciprocal motion having a non-uniform velocity, the stretch of the rod further varying the ve-- locity. During the downstroke, the plunger gathers an accumulation of crude oil thereabove and dle of its upstroke. However, due to the weight of the column of oil or hydrostatic load, imposed upon the plunger, the rod is stretched or elongated and the velocity is retarded until the inertiaof said column is overcome. The velocity then exceeds thatof the harmoniomotion for a portion of the upstroke and is finally retarded nonuniformly by the rod reaching its upper limit of 7 for deviations caused by'passingdovmwardly or falling through the accumulated oil and overtravel of said plunger, the latter being due to stretching or elongation of the rod by the downward acceleration of the mass thereof.' Under any condition of conventional well pumping,

wherein the plunger is reciprocated in a straight linemotion translated from rotary 'or.ciroular motion, the actual workingtime of the pump is substantially one-half thetimeof 'a complete a cycle and the remaining time is consumed in dropping said plungerfor a return stroke.

One object of the invention is to provide an improved pump mechanism for efficiently and economically elevating well fluids from ap'ro ducing formation inaccordance with the foregoing prerequisites soas to prevent the separation of the well fluids and the escape of the valuable lighter hydrocarbons, v

An importantobject of the invention is to provide an improved pumping mechanism having expansible means adapted to be inflated and deflated to lift fluids withina well bore, the conducting means having a, relatively small; diameter and volume whereby the pressure fluid mayf be conducted to and exhausted'from said memher as rapidly as desirable withinthe limits of goodpractice, as controlledbythe characteristics and condition of the producing formation.

Another object of the invention is to provide terially increasing the, duration of. ;the lifting intervals so as to permit the use of a fluid-ofrela-- tively low pressure or volume. v

A further object of the invention is to-provlde an improved pumping mechanism, of the char- 7 3 V acter described, wherein the expansible member is elastic and is disposed Within a chamber for receiving and accumulating well fluids, said member and chamber having substantially equal dimensions so that the area of the chamber is completely filled or occupied by the inflated member, one end of said member being free so as to permit collapsing .thereof upon deflation,

whereby the deflated member occupies only a small area of said chamber and a maximum volume of well fluids may be displaced upon inflation of said member without undue distortion or stretching thereof.

Still another object of the invention is to provide an improved pumping mechanism, of the character described, which may include a single expansible member and receiving chamber or a plurality of the same, whereby in deep wells the fluids may be "lifted in stages so as to eliminate the necessity of placing the lifting fluid under an excessive pressure.

A still further object of the invention is to provide an improved pumping mechanism, of the character described, having valve meansfor controlling the admission of the pressure fluid to the, expansible member and exhaustion of said fluid therefrom, the valve means being so constructed as to open and. remain open for supplying the fluid until inflation of said member is completed, the excess pressure acting upon and closing saidvalvemeans and opening an exhaust port to permit escape of said fluid and deflation of the member. 1 j V v Another object of the invention is to provide an improved pumping mechanism, of the character described, having means for positively controlling, the rate of exhaustion of the pressure fluid and thereby determine the rate of entry of the well fluids into the pumping mechanism from the producing formation and the vacuum or suction exerted upon said well fluids, due to the exhaustion rate' of said pressure fluid, so as to prevent liberation of the" lighter hydrocarbon constituents fromthe well fluids; the controlling meansbeing adjustable in accordance 1 V with the characteristics and conditions of the formation tion. it x I A'co'nstruction designed to carry out the invention will be hereinafter described together with otherfeatures of the invention.

The invention will be more readily understood from a reading of the following specification and by reference to the accompanying drawings, wherein an example of the invention is shown, and wherein: ,7

Figure 1 is a view, partly in elevation and partly in section, of a pumping mechanism; constructed in accordance with the invention, mounted in a 'well bore,

Figures 2 and 3 are enlarged, longitudinal, sectional views, partly in elevation, of the lower portion of the pumping mechanism and showing the two lowermost stages,

Figure 4 is an enlarged, transverse, vertical, sectional view of the upper portion of the lowermost stage, showing the connection of the expansible member and the check valve construction, I

Figure 5 is a, view, similar to Figure 4, of the upper portion of one of the upper stages shown inFigure3,

Figures 6 and 7 are'views, similar t'o Figure 2, of the lowermost stage and showing the expanto provide the most desirable operasible member deflated and partially inflated, re spectively, 1

Figure 8 is an enlarged, transverse, vertical, sectional view of the surface control valve in its closed, exhausting position,

Figure 9 is a reduced, horizontal, cross-sectional view, taken on the line 9--9 of Figure 8,

Figure 10 is a view, similar to'Figure 8, with the valve member in elevation and showing the same in its open, fluid admitting position, and

' Figure 11 is an enlarged, transverse, vertical, sectional view of a moisture trap. In the drawings, the numeral l0 designates a well bore which extends to the producing formation F and has the usual well casing ll mounted therein. A well or casing head I2 is connected to the upper end of the casing H at the surface and includes the usual lateral outlets l3 and carries a flow cross I4. Depending from the head I2 and communicating with the cross I4 is a tubing or flow pipe, indicated generally at [5, which extends axially through the casing to a point below the level of the well fluids and includes several spaced sections. The annular space between the tubing and casing is preferably sealed off within the head I2 in a conventional manner by suitable means (not shown) so as to permit the holding of a desirable backin Figure 4, the lower end of the chamber A is connected by suitable coupling collars I6 and i1 and a, swaged nipple I8 to a perforated bull plug or. other well screen [9 which has been shown for the purposes of illustration as being disposed within the open well bore. In deep wells, similar pump chambers B are connected in the tubing l 5 at predetermined, spaced intervals and, as will hereinafter be more fully explained, the number of such chambers being subject to variation.

As is clearly shown in Figures 2 and 4, the chamber A includes an elongate, tubular body or sleeve 20 of greater diameter than thetubing and communicating therewith. The collar 16 connects the lower end of the sleeve to the nipple l8, while the upper end of the sleeve is connected by a similar collar 2! to a swaged nipple 22 which, in turn, is secured to a section of the tubingby. a coupling collar 23. The external diameter of the latter collar is enlarged so as to provid a relatively thick wall. Thus, the well fluids may flow through the perforations of the bull plug l9 into the nipple I 8 and then into the interior of the chamber A, the height or level attained by said fluids being determined by the depth or position of said chamber. For controlling'the' admission of the fluids to the chamber, the usual standing valve 24 is mounted in the lower end of the nipple I 8 above the perforated plug l8. The valve 24 includes a conventional seat 25, ball 26, and combined clamping ring and ball cage 21, the clamping ring of the cage and the seat being confined.

the annular wall thereof preferably thickened and 7 reinforced to provide a neck 29. A suitableclamp ing ring or split bank 30 fastens the reinforced neck 29 in surrounding relation around a" short sleeve or nipple 3| which is provided with a plurality of external, peripheral grooves or recesses 32 for coacting with and receiving the material of said neck to seal off therebetween upon tightening of the band; or if desired the neck of thesack could be vulcanized on the nipple. The nipple 3| is of less diameter than the bore of the swaged nipple |8 and is screw-threaded into a reduced, intermedial screwed counter bore 33, of the collar 23; so as to depend internally of said swaged nipple. A partition 34 extends transversely across the intermediate portion of the bore of the nipple 3| so as to separate the upper portion of the bore of said nipple from the lower portion thereof. The nipple has a plurality of ports formed therein immediately above the partition for establishing communication between the interior of the chamber A and the tubing section I5, which is connected to the upper end of the collar 23.

The lower end of the nipple projects downwardly from the neck 29 into the sack and is reduced at its lower end; being provided with a constricted opening 36, whereby collapsing of the sack upon deflation thereof is facilitated (Figure 6). For trapping well fluids within the tubing above the chamber A, a check valve 3'1, which is substantially identical to the valve 24, is disposed within the collar 23 upon an internal, annular shoulder 38 immediately above the counter bore 33.

The sack 28 is normally deflated or collapsed as shown in Figure 6 so as to occupy only a small portion ofthe area of the chamber A. However, upon inflation, the sack will substantially flll or occupy the entire area of its chamber (Figures 2 and 4) and, due to said sack normally having an external diameter substantially equal to the internal diameter of its chamber and a-substan tially equal length, there is little or no stretch ing or distortion of the sack upon inflation thereof. Since the purpose of the sack is to displace or force well fluids from the chamber A into the communicating tubing I5 thereabove, it is essential that said sack occupy as little space'as possible, when collapsed, to permit the accumulation of a maximum volume of said fluids within said chamber and, when inflated; to substantially fill the chamber so as to elevate the fluids. In order to assure initial inflation of the lower portion oi the sack, so as to prevent the trapping of fluidv within the chamber therebelow, the annular wall of the lower portion of said sack may be reduced in thickness as shown at 39. in Figures 6 and '1. If desired, the same results could be obtained by inverting the sack.

For inflating the sack 28 and permitting the collapse or deflation thereof, a suitable pipe or macaroni string 49, extends through the wall of the nipple 2 2 and into the lower portion of the nipple 3| below the partition 34 so, as to communicate with the bore of said nipple and the sack. As has been explained, the sack is normally collapsed or deflated so as to occupy only asmall area of thechamber A (Figure 6) and such col-U lapse or deflation will be assisted by the pressure of the well fluids, due to the fact that said chamber is immersed in said well fluids which are ad? mitted by and through the valve 24. A suitable pressure or lifting fluid, such as air or gas, is conv ducted downwardly through the string 43; which extends up through the casing II to the casing head l2 and delivered to the sack for inflating the same. This inflation of the sack will close the valve 24 against downward escape of the well I fluids from the chamber and will displace orjorce,

6 fluidsaccumulatedl in said chamber, upwardly therein and out through the'ports 35 into the upper portion o'fthe nipple 3| above the partition 34 and then through the valve 31 into the tubing |5. As indicated in Figure 7, the inflation of the sack will be gradual and the lower portion thereof will be initially inflated so as to prevent theltrapping of well fluids below'said sack. Manifestly, the elevated well fluids will be trapped and accumulated within the tubing due to the provision of the valve 31. Upon the complete expansion of the sack as shown in Figures 2 and 4, said sack will fill or occupy substantially the entire area of the chamber A, whereby little or no well fluids remain within said chamber and also whereby a maximumvolume of said fluids is displaced upwardly. The pressure fluid is then permitted to escape from the sack, as will be hereinafter de-- scribed, so as to'permit collapse or deflation there'- of and the admittance of additional well fluids into the chamber A dueto opening of the valve 24; It is pointed out that the small diameter of the string 40 makes it possible to quickly inflate and deflate the sack, because only the pressure fluid within said sack need be replaced or exhausted; however, the sack may be more quickly deflated than inflated, as will hereinafter be more fully explained. V

Asshown in Figure 1, the macaroni string 40 is connected through one of the lateral outlets |3 of the head |2 to a line 42 which has connec-" tion. with the outlet side of a surface control valve 43. A suitable conductor or line 44, having a conventional needle valve 45 mounted therein, connects the inlet side of the valve 43 to a storage tank 46, to which a fluid, such as air or gas, is supplied under pressureby a suitable compressor 41 and pipe 48. A motor or engine 49 is provided for driving the compressor. 7

As shownin Figures 8 to 10, the control valve 43 includes a cylindrical block 5| and a cylindrical head 5|).which are secured together by suitable bolts. I 2

An axial, cylindrical bore 52 is formed in the upper portion of the block 5| which is provided with radial outlet and inlet ports 53 and 54 which extend from the bore and have their outer portions screw-threaded for receiving the outlet and inlet lines42 and 44,, respectively, whereby the bore establishes communication. between said lines. An axially-aline d, reduced counterbore 55 communicates with the lower end of the bore 52 and extends entirely through the lower portion of the block 5| so as to be open to atmosphere.

? ablewithin the counterbores 55 and 55, respectively." The piston 58 is of less height or'length than its cylinder and the plungers59 and 60 are slightly less in length, than their respective'counterbores, whereby said piston is freely reciprocal within the valve block. Since the upper plunger 59 is of greater diameter than the lower plunger 60, the top of the piston 58 has a greater effec-' tive cross-sectional area than the bottom thereof. For sealing off the cylinder 52 and between the plungers and theircounterbor'es, the inneroends V In the lowerportion of the head 50, a counterbore tic material.

7 hereinbef ore.

V 7 of the latten'adjacent' said cylinder, are counter bored or recessed as shown atGl and 62, respec-' tively, to receive annular. packing members or rin s 53 and 64, of rubber or other suitable elas- The upper recess 6| and'packing ring 53; which are disposed in the head 50 above the cylinder, are of a diameterslightly greater than the diameter of said cylinder so as'to project peripherally therebeyond for engaging the upper end of the block 5|, and sealingoff the upper end I v of the cylinder when said'head is secured to said block; The upper portion of the valve block,

' which is engaged by the ring 63, serves as a shoulder or seat for supporting and retainin said ring in place. The external diameter of the lower recess SZand packing ring 64 is slightly less than the'diameter of the cylinder, whereby said ring seals off around the lower plunger'iii); as well as between said cylinder "and the lower counterbore 55., l

In order to prevent the piston 58 from engaging the bottom of the cylinder and closing the inlet port 54, an annular shoulder 65, which is of less diameter than the upper plunger 59, is formed at the upper endof the plunger 60 and engages the packing ring 64 when the valve piston is in its lower position (Figure8). .Thus, even when the shoulder 65 is seated against the ring in and'closes the upper end of said duct. The ball 19 is held in engagement with its seat by means of a coiled spring H and "an adjusting screw 12 which is screw-threaded through a suitable packing nut or collar'13, the latter being screw-threaded into the upper end of the valve chamber 69 for closing the same. A transverse 64, the effective area of the bottom of the piston head is greater than'that of its'top and the ad mission of pressure fluid through the inlet port 54 will result in the fluid actingupon the bottom of the piston head and lifting the piston 51 to the position shown in Figure 10; Since the outlet port 53 is disposed in a horizontal plane a slight distance above the inlet po'r t, communication between said ports is established upon this this upward moveinent of the piston. Due to this communication, the pressure fluid from the storage tank is permitted to flow through the line 42 and pipes 4| and 49 to the interior of the sack 28 for inflating the same as has been explained The piston 5! will remain in its upper positionKFigure 1 0) until the sack'is fully expanded or inflated as shown in Figures 2 and 4. Due to the opening of the outlet port 53, the pressure beneath the piston head 58 will be materially reduced and said piston head will cease to move upwardly when its bottom is above said port. Therefore, the topof thepiston head will bespaced below the upper end of the cylinder when the piston 51 is in its upper position;

For by-passing pressure fluid to the upper end periphery thereof piston does not alter the operation of the valve,

as heretofore explained, due to the greater cross sectional area of the bottom of said'piston. In

orderlto lower the piston 51 and shut the supply or pressure fluid upon complete inflation of the sack 28, it isnecessary to conduct said fluid to the upper counterboreefi) whereby the pres- 1 sure of the fluid will act upon the upper end of the plunger 55. For accomplishing this purpose, an inclined port 6? extends .from the upper portion of the bore 52 to the upper end of the block all and communicates with a vertical duct 68 formed in the head 59, 'An enlarged valve chamber 169 is formed above the duct de end houses a: spring-pressed-ball: 19 which is seated 7 below the cylinder or duct '54 establishes communication between th'evalve chamber and the upper end of the c'ounterbore 56. I

It is pointed out that the ball 10 is normally seated and the compression of the spring ll is adjusted by means of the screw 12 to hold the valve in its seated position until the pressure within the cylinder 52 exceeds the pressure necessary to completely inflate the expansible sack 28. Manifestly, since the pressure of the fluid within the tank 46 is'in excess of the pressure required to completely inflate the sack, said pressure will build up within the cylinder and will unseat the ball 10 and flow through the chamber 69 and duct. 14 into the upper counterbore 56. The combined area of the plunger 59 and the top of the piston head 58 being'greater area than the bottom of said head, due to the provision of the plunger 63 and shoulder 65, the admission of the pressure fluid to the upper counterbore will result in downward movement of the piston 51 from its upper, open position to its lower closed position (Figure 8). As has been explained, the piston head 58 overlies or covers the outlet port 53 so as to'shut ofi the flow of the pressure fluid to the line 42 when the piston is in its lower position. It is pointed out that the ball valve 76 will seat and close the duct 68 upon movement of the valve element to its lower position, since the pressure exerted against saidball valve is no longer suflicient to withand due to'the equalization of the pressure within the chamber 69 with the pressure within said duct. Manifestly; the seating of theball valve will shut off the flow of pressure fluid to'the upper 'counterbore 56 and said'fluid will be trapped within said counterbore as well asin the duct 14 and chamber 69. In order to relieve this pressure, and permit subsequent upward movement of the piston, an axial duct"'i5,of.relatively small diameter extends entirely through the piston 51, establishes communication between the upper counterbore andthe atmosphere and thereby permits the trapped pressure to bleed or dissipate itself from said'counterborel'radial duct 74 and chamber 69. As soon as this" trapped pressure fluid approaches atmospheric pressure, a predetermined pressure drop occurs and the pressure exerted against the greater area of the bottom of the piston head will again raise the piston so as to open the outlet port 53 and therebysupply pressure fluid to the expansible sack 28.

F'or controlling the escape of the pressure fluid from the expansible sack, an angular bypass duct or port 16 is formed in the valve block 5| and extends downwardly from the outlet port 53, then diametrically or" said body immediately 52 and the lower packing ring l 64 and its recess 52. A manually-adjustable,

needle valve 11,. similar to the needle valve 45 is connected to the by-pass duct 16 by means of a short pipe 18 which is screw-threaded into the outer end of said duct. The lower counterbore 55 intersects theb'y-pass duct 15 and said duct is closed by the plunger 60 when the piston is in V its upper or raised position as shown in Figure 10, Forestablishing communication between the two portions of the by-pass duct, an annular groove or recess 19 is formed in the external peripheryof the plunger 60 and this groove re isters' with said duct when the piston is in its lowered position (Figure 8). Thus, when the fluid pressure is cut off from the expansible sack by the piston being in its lower position, the fluid within said sack may exhaust by flowing upwardly through the pipe 40 into the line 42, port 53, duct 16, groove I9 and pipe I8, and then out through the valve I1. Since the upward movement of the piston to its open position moves the groove 19 out of registration with the by-pass duct, flow through said duct ,is prevented and there will be no escape of the fluid flowing through the valve 43 to the expansible sack.

The needle valve '11 is conventional and merely meters or regulates the rate of flow of the pressure fluid exhausted from the expansible sack and, therefore, the rate of deflation or collapse of said member as well as the rate of entry of the well fluids into the chamber A. It is pointed out that the valve 11 may have its outlet or discharge opening connected to the intake of the compressor 4'! or may, as shown be open to the atmosphere. The valve 45 is substantially identical to the valve 11 and is provided for the purpose of controlling the rate of flow of the pres sure fluid supplied throughthe valve 43 to the sack 28. The adjustment of these needle valves is subject to variation and said adjustments may bedissimilanwhereby the pressure fluid may be exhausted from the sack at a different or faster rate than the admittance of said fluid thereto. It is desirable to exhaust the pressure fluid at a rate much more rapid than the admittance rate of said fluid, whereby the actual working or lifting time may be of prolonged duration.

Due to the relatively largevolume of the chamber A, a sizable quantity of well fluids'maybe lifted upon each inflation of the expansible sack and such inflations may be infrequent so as to permit the use of a lifting fluid of relatively small volume or low pressure. Since the exhaustion rate of the pressure fluid controls the rate of entry of the well fluids into the chamber A as Well as the vacuum or suction exerted upon said well'fluids and the Velocity of the same in flowing from the formation F, separation and escape of the lighter hydrocarbon. constituents from the well fluids may be prevented by properly adjusting the exhaust needle valve 11 inaccordance with the characteristics and condition of the producing formation. Of course, this valve is adjusted to provide a maximum rate of exhaustion without creating an undesirable or excessive vacuum or velocity of flow. Also, a desirable back-pressure is held upon the formation by the means (not shown) within the casing head I2 which seals off the space between the casing H and tubing I5. In order to provide a relatively slow admission of the pressure fluid, the needle valve 45 may be suitably adjusted so as to admit said fluid at the desired rate.

"A pump of the construction described hereinbefore is limited as to the depth of its installation below the surface, due to the fact that it would be uneconomical to employ an operating fluid having an excessivelyhigh pressure; Therefore, in wells relatively deep, it is desirable to employ a plurality of lifting stages and each stage includes one of the chambers B as shown in Figures 1, 3 and 5.

--Each chamber B is very similar to the cham- 10 ber-,A, but is of greater length, and includes a similar sleeve 00 having its upper end connected to the tubing I5 by a collar 8|, a swaged nipple 82 and a coupling collar 83. As shown in Figures ,3 and 5, a similar collar 84, swaged ,nipple' 85 and coupling collar 86 connect the lower end of the sleeve to the tubing 'therebelow. The upper coupling collar 83 has an enlarged external diameter to provide a relatively-thick wall and the bore of said collar has its lower portion enlarged to form a recess or socket 81 for receiving the upper end of the swaged nipple 82. As shown by. the numeral 88, the bore of the upper endor neck of the nipple is substantially equal to the external diameter of the tubing I5, whereby a short pipe sleeve89, of substantially the same diameter as said tubing, may extend throughsaid nipple neck'and be screw-threaded within the internal lower portion of the collar 83. The short sleeve 89 depends a short distance into the chamber B and has its lower'end connected to a swaged nipple Siiby a special coupling collar 9| which-is substantially identical to the collar 23 and which includes an internal,'annular shoulder 92 and a reduced, screw-threaded counterbore or socket 93 therebelow. A check valve 94, substantially identical to the valves 24 and 31, is mounted within the collar BI and is held in position by being clamped between the shoulder 92;;and the lower end of the short sleeve 89 for. trapping well fluids thereabove, as will be hereinafter more fully explained. The counterbore 93 receives the-upper end of a tapered nipple 95 which extends throughthe upper endor neck of the swaged nipple 00 to a point slightly below said neck. The nipple '95 is substantially identical to the nipple 3 Iand has a similar transverse partition 06 with radial ports 51 thereabove. for establishing communication between the-upper portion of said nipple 95 and the exterior thereof. As is-clearly shownin Figure 5, an expansible member orsack 88, substantially identical to but of a le ssdiameter and greater length. than'the sack 28, has its reduced, reinforced upper end or neck 99 engaging aroundand fastenedto the lower portion ofthe inner'nipple 95 above its tapered or constricted throat I02 by a suitable clampingband or ring I00. External, peripheral grooves I'0I are-formed in the inner nipple for receiving the material of the tube neck 99 upon tighteningof the band I00. 'I'hepressure fluid is conducted to the sack 98 from the pipe 40 by a branch pipe I03, which extends from said pipe, through the swaged nipple 82, then through the swaged nipple 00 into the lower portion of the nipple 95 below its partition 96 so as to communicate with the interior of said sack. An elongate,

cylindrical sleeve I04, of less diameter than the sleeve 80, surrounds the sack 98 and depends from the nipple to which it is connected by means of a suitable collar I05. The sleeve I04 is of greater length than the sleeve 20 of the chamber A, but of less length than the sleeve 80, so as to terminate above the lower end thereof and is connected by. means of. a collar I06, a swaged nipple I0'I-and a special coupling collar I08 to a perforated bull plug I09, which ispreferably ,dis-

posed within the reduced or neck portion of the lower-swaged .nipple85. qAcheck valve IIO is mounted in the coupling collar I00 by being clamped between the nipple I01 and plug I09 and 7 this valve as well as the other parts 'are substantially identical to .the valve 24; plug 25,

1 connected thereto provide an accumulating chamber C of substantially the same capacity as j thechamber A for receiving the well fluids lifted from said chamber A by the sack 28. n M

Upon inflation of the sack 28 as shown in Figure 2, the well fluids lifted from the chamber A through th valve 31 will build up or accumulate within the tubing I 5 thereabove and within the chamber B. Although the chamber B and its sleeve 80 have substantially the same diam- 3 eter asthe chamber A and its sleeve 26, the

former are of. greater length so as to have sub- 1 stantiallythe same capacity or volume for ac- 1 cumulating the lifted well fluids. is actuated in exactly the same manner as the The sack 98 sack 28 and is preferably inflated and deflated simultaneously therewith. As soon as the Well 1 fluids commence to accumulate within the chamher (2, said fluids will flow through the perforations of the plug I09 past the valve IID into thechamber C upon exhaustion of the pressure fluid and deflation of the sack 98. Initially no I well fluids are present within the chamber to resist inflation of its sack 98 and, therefore, said ber C upon first entering said chamber and will I continue to fill the same uponeach subsequent 1 actuation'of the sack 28;. Upon inflation of the sack 98, the valve I III will be closed and the Well fluids within'the chamber C will be forced or lifted upwardlythrough the space between the nipples 90 and%, then through the ports 91,

'3 the upper portion of said nipple 95 and valve 94 into the short sleeve 89 and tubing I5 thereabove 1 (Figure 5).. As has been explained, the valve 9d functions in the same manner as the valve 31 of I :the chamber A for trapping and preventing the escapebf wellfluids lifted therethrp l h. With I the surface control valve 43 in the position shown inl'gigure 8, the pressure fluid within the sack 98 will exhaust. through the pipe I03 into the pipe 4.0 and will be conducted together withithe pres- 12 explanatory thereof and various changes in the size, shape and materials, as well as in the details of the illustrated construction may be made, within the scope of the appended claims, without departing from the spirit of the invention.

What I claim and desire to secure by Letters Patent is:

1. In a well pumping apparatus, the combination of, an accumulating chamber adapted to be immersed in the liquid in a well,an elongate expansible sack mounted in said chamber and free to collapse, a conductor f or supplyin pressure fluid to the upper end of the sack and for exhau'sting such pressure fluid therefrom connectedto said sack and adapted to extend to the top,

of a well, the lower end of the sack being free and unsupported, an automatic valve for alter hating supplying pressure fluid to the conductor and exhausting such fluid therefrom,'means for supplying fluid under pressure to said valve, a well tubing extending from the upper end of said chamber, means for discharging well liquid from the chamber to the tubing, means for controlling.

the supply ,of pressure fluid to the valve, and means forico'ntrolling the exhausting of pressure fluid from the valve, whereby the pressure fluid may be exhausted from the sack at a higher rate than that at which it is supplied'thereto.

2. In a well pumping apparatus, the combination of, an accumulating chamber adapted to be immersed in the liquid in a well, an elongate expansible sack mounted in said chamber and free to collapse, a conductor for supplying pressure fluid to the upper end of the'sa'ck and for exhausting such pressure fluid therefrom connect-' ed to said sackand adapted to extend to the top of a well, the lower end of the sack being free and unsupported, an automatic valve for alternating supplying pressure fluid to theeonductor and exhaustingsuch fluid therefrom, means for supplying fluid under pressure to said valve, a

sure fluid from the sack 28fto the surface so as f to escapeby means ofthe line 42, angular duct It, groove 19 pipe 13 and needle valve TI, The well fluids within the chamber B will then again flow iritothe chamber 0 so as to assist in col- 7 la'psing or deflating the sack 98 and to substanwell tubing extending from-the upper end of said chamber, means for discharging well liquid from the chamber to the tubing, a control valve comnected in the fluidpressure supply, and a control 7 valve connected with the pressure fluid exhaust oi the valve.

3. A well pump including acylinder adapted to be immersed in a well, awell fluid inlet valve at the bottom of the cylinder a well fluid outlet,

' valve at the top of the cylinder, a well tubing tially flll said chamber, whereby said Well fluids willbe lifted or forced upwardlyupon subseiquent inflation of said sack, V r V f In order to prevent the creation of an undesirable pressure within the chamber B and to per- :mit the escape of any excess well fluidsfwhich might accumulate therein, a plurality of vent openings I I I are formed in the swaged nipple 82 which is disposed at the top of the chamber above its sleev 80. "A moisture trap I I2 (Figure 11) may be connected in the macaroni string adjacent the point at which said string 40 extends through the swaged nipple 22 of the chamberA.

3 ffrhepipe is dividedin the trap and the ends thereof 'o ifset 'in'the usual manner. A springpressed downwardly opening dumping valve I I 5 engages a s'eat IlII in the bottom of the'trap.

:iPeriodically increasing the pressure of the fluid flowing through the string 40 will exertsuflicien'tpress'ure upon" the liquid accumulated in the trap to open the valve and discharge such liquid".

The.foregoing description.of the invention is connected with'the top of the cylinder, an expansible sack in the cylinder disposed to expand 7 to the full internal cross-sectional area of said cylinder, the upright wall of; the cylinder being imperforate, means forsuspending the sack' in the cylinder, and means for supplying a pressure fluid to the sack through its support.

4. A well pump as set forth in claim 1, and a' moisture trap connected in the pressure supplyf ,mean's adjacent the chamber.

-5. A well pump includingga cylindrical chain; oer adapted to beimmersed in the liquid in a well and having a well fluid inlet valve at itsbottom, a nipple mounted at the top of the chamber and extending only into the upper end iof said chamher, an inflatable elastic sack suspended from said nipple anddepending into said chamber, said sack being free to collapse, 'mea-ns'for, supplying a pressure fluid to and exhausting such fluid from the nipple for said sack to inflate the latter to the inner annular wall of the cylinder and to collapse said sack, means for conducting well fluid displaced by the sack from the'cylinder, and

13 a well tubing connected to said conducting means.

6. A well pump as set forth in claim 5, and a back flow valve connected with the tubing above said nipple.

7. A well pump including, a cylindrical chamber having an inlet valve at its bottom, an elasticvsack suspended in the chamber, and means for supplying a pressure fluid to' the sack, the

lower wall of the sack being reduced in thickness to cause initial expansion thereof, whereby the trapping of well fluid in the chamber is prevented.

t. A well pump including a cylindrical chamber adapted to be immersed in the liquid in a well and having a well fluid inlet valve at its bottom, a nipple mounted at the top of the chamber and extending only into the upper end of said chamber, an inflatable elastic sack suspended from said nipple and depending into said chamber, said nipple having a pressure fluid passage and a well fluid discharge passage separate from to be installed in a well, a well fluid inlet valve at the bottom of the cylinder, a well fluid outlet valve at the top of the cylinder,, a well tubing connected with the top of the cylinder, an expansible sack in the cylinder disposed to expand to the full internal cross-section area of said cylinder, the upright wall of the cylinder being imperforate, means for suspending the sack in the cylinder, means for supplying a pressure fluid to the sack through its support, and-a larger cylinder surrounding and spaced from the first named cylinder and communicating therewith throug the well-fluid inlet Valve thereof.

JOSEPH R. NORTON.

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