US2005995A - Rodless pump - Google Patents

Description

June 25, 1935. G. s. KNox RODLESS PUMP med may 29. 1954 5 Sheets-Sheet l I n d n n n n r l r r l f I I I l n n n n l n n v n r v v v u n n n n f AnrrnnnrnrA vnr vrlr inrlkc G. s.. KNox 2,005,995

RoDLEss Y PUMP Filed May 29, 1934 5 Sheets-Sheet 2 Jule 25, 193s.

5 Sheets-Sheet 5 III 'June 25, 1935. G. s. KNOX RODLESS PUMP Filed May 29, 1954 5 Sheets-Sheet 4 Attorncy Patented June 25, 1935 l PATENT ori-Ica RoDLEss PUMP Granville S. Knox, Los Angeles, Calif., assigner `to W. L. Cummings, Los Angeles, Calif.

Application May 29, 1934, Serial No. 728,078

15 Claims.V (Cl. 10S-46) This invention relates to self-contained or rodless pumps for oil wells, in which the pump unit itself contains a hydraulic motor for reciprocating the pump plunger, the motor being actuated by oil at high pressure delivered from a source at the surface to the motor through small central tubing extending down through the well within the oil tubing through which pumped oil is discharged from the pump up to the surface. In view of the obvious advantagesl of pumps of the general type to which this invention relates over conventional sucker rod pumps, many attempts have been made to develop commercially successful rodless pumps. However, serious obstacles have been encountered during this development. `One defect of pumps which have been otherwise satisfactory is that their over all diameter has been too great to permit their entry into oil tubing of the small dimensions necessary 20 in many deep wells, thereby necessitating the mounting of the pump on the lower end of the oil tubing. 'Ihe disadvantage of this arrangement is that both the inner and outer tubing strings have to be pulled whenever the pump is removed. `On the' other hand, a pump small enough to enter into the outer tubing string can be removed by pulling only the inner tubing without disturbing the outer tubing.

It has been impracticable to reduce the overall diameter of rodless pumps, as they have been previously designed, below denite limits because, to the best of my knowledge, such pumps comprised tubular body members containing pump and/or motor barrels with several fluid passages the over allv diameter of the body member were reduced in size, it was necessary to reduce the size of the barrel or of the iluid passages to such an extent as to greatly reduce the capacity of the pump.

An important object of the present invention is to reduce the over all diameter of a rodless pump suilicient to permit its insertion in oil tubing of reasonable size without unduly decreasing its eiiiciency of operation. This object is attained by employing in the motor a traveling barrel and stationary piston construction instead of the usual stationary barrel and traveling piston, and positioning the valve mechanism which controls the flow of fluid to and from the working chamber of the motor within the stationary piston assembly. This permits the use of short iluid passages extending through the piston assembly instead oi longitudinally outside of the barrel, for

extending past one'at least of the barrelsand, ifV

drawings.

carrying fluid to and from the working chamber.

Another object of the invention is to provide a rodless pump assembly in which the pump is readily removable as a unit from the motor with- 5 out disassembling the motor. This permits the use of the same motor operated by fluid at the same pressure in Wells of different depths by merely substituting pumping units of diilerent capacities. It also permits ready replacement of 10 a worn pumping unit.

` Another object is to provide a rodless pumping unit in which the motor is fully enclosed and all its moving parts protected from contact with pumped oil fromthe well, which pumped oil often contains vsand and grit destructive to a moving mechanism.

Another` object is to provide a pump structure adapted to be attached to theI lower end of the inner tubing and lowered into and removable from the well on the inner tubing but in which the weight of the inner tubing is supported from the outer tubing independent of the pump when the latter is in working position, thereby preventing possible distortion of the pump by the weight of the inner tubing.

Another object is to provide a. oating working barrel in the motor supported only at one end so that it automatically aligns itself with the plunger and is also relieved of allunnecessary compression or tension strains which might tend to warp the barrel and freeze the enclosed plunger.

Another object is to provide a. rodless pump motor having a hydraulically actuated workingvalve, which valve is light in weight, has a short stroke and is cushioned at the end of each stroke to eliminate shock and thereby insure long life and high eiliciency.

Another object is to provide a simple and positive locking mechanism for holding the valve mechanism in a desired position while the pump is being transported to and lowered into a well, whereby any necessity for priming the motor at the surface before lowering it into the well is eliminated. Heretofore with pumps of this type such priming hasbeen necessary to uuid-lock the valve mechanism in an operative position.

Other objects and various specic features of the invention will become apparent from the fol- 50 lowing detailed description which refers to the In the drawings: Figs. 1 to 4 are schematic diagram illustrating the principle ci operation oi my pump, the four 56 Fig. 10A is a longitudinal sectional view show- Ing a modification of that portion of the pump structure disclosed in Fig.- 10;

Fig. 13 is a cross section of the pump taken in t the piane :nnxm of Fig. 6;

Fig. 14 is a cross section taken in the: plane XIV-XIV of Fig. 7;

Fig. 15 is a cross section taken in the plane XV-XV of Fig. 9; 1

Fig. 16 is a cross`section taken in the plane XVI- XVI of Fig. 10;

Fig. 17 is a cross section taken in the vplane XVII- XVII of Fig. 10;

Fig. 18 is a cross section taken in the .plane XVIII- XVIII of Fig. 12, and

Fig. 19 is a detail vertical section illustrating a preferred method of joining adjacent sections of my pump.

Principles of operation A complete understanding of the construction and operation of my pump can be most quickly conveyed by first explaining the general principles of operationI with reference to the schematic diagrams of Figs. 1, 2, 3, and 4 and then following through the details of construction of an actual pump as disclosed in Figs. to 18, inclusive.

Referring to Fig. 1, there is shown a well casing I, within which are positioned an outer tubing string 2 and an inner tubing string 3, these strings extending from that portion of the casing in which the pump is located upwardly through the casing to the surface. The outer tubing 2 constitutes the usual oil tubing through which pumped oil is delivered to the surface. The inner tubing 3 constitutes a conduit for the transmission of clean oil at high pressure from the surface down to the pump unit for operating the latter. It is to be understood that the outer tubing 2 may be extended clear to the bottom of the well and be supported, in part atleast, by an anchor placed on the lower end thereof. Ordinarily, of course, the pumping unit is positioned closely adjacent the bottom of the well and submerged in the oil which stands in the casing I.

The pumping unit when positioned in the well is supported from the outer tubing 2 and to this end the tubing is provided with an inwardly projecting shoulder II, the inner edge of which is beveled to constitute a seat for supporting and sealing with a block I2 on a stationary motor plunger and pump barrel assembly d. Block I2 and shoulder Il together constitute a partition in the outer tubing 2 so that exhaust oil from the motor and pumped oil from the pump delivered into the outer tubing 2 above the shoulder will be discharged to the surface of the well, whereas that portion of the tubing 2 below the shoulder will be piled-with oil from the well, this oil being permitted to enter through apertures I3. The component parts'of the stationary .motor plunger and pump barrel assembly 4' include a pump barrel I4 extending downwardly below the block I3, a connecting stem I5 extending upwardly from the block I2 tothe plunger proper I6 having a lower shoulder Il and an upper shoulder I8., which plunger is connected at its upper end to the lower end of 'the inner tubing 3.

The traveling motor barrel and pump plunger assembly 5 comprises a barrel I 9 which seals with the shoulders and I8, and together with those shoulders and the portion of the motor plunger therebetween, defines the working chamber of the motor. The barrel I9 is provided with an inwardly extending shoulder 20 positioned intermediate the shoulders I1 and I8 on the plunger and which seals with the plunger and constitutes the moving piston of the motor. The barrel I9 is secured at its lower end to a pump plunger rod 2| which extends through and seals with the block I2 and terminates in a pump plunger 22. The plunger rod 2| is hollow, as shown, and is provided with a ball check valve 23 at the lower end. The upper end of the passage within the plunger rod 2| communicates through ports 24 with the interior of the outer tubing 2 above the shoulder II. 'Ihe pump barrel Il is provided with a standing valve 25 in the lower end thereof and with surge ports 26 in its upper end, these ports communicating with the space below the shoulder I I in the outer tubing.

That portion of the stationary motor plunger assembly positioned within the working chamber of the motor is hollow, constituting a valve chest 6, within which there is mounted a vertically reciprocable piston valve 1, the latter being provided with four vertically spaced shoulders, which seal with the walls of the valve chest and define with the walls of the valve chest three chambers or pockets 21, 28 and 29, respectively. The piston valve 'I is actuated by fluid pressure delivered successively to opposite ends thereof and, to control the admission of the pressure iiuid to the vends of the piston valve, an auxiliary valve 8 is provided.

This auxiliary valve 8 constitutes a rod extendingv through the valve chest and through the main valve 'I therein and sealing in guide channels in the stationary plunger assembly at opposite ends of the valve chest 6. The auxiliary valve 8 is adaptedl to be reciprocated by the traveling barrel of the motor through the medium of a motion reversing mechanism. Thus the lower end of the auxiliary valve 8 is secured to a rack 3U meshing with a pinion 3| rotatably supported within the stationary plunger assembly' 4, which pinion also meshes with a rack 32 connected to -an actuating rod I0 provided with a cross head 33 on its lower end which is engaged either by a cross head 34 or a shoulder 35 on the traveling barrel assembly.

The remaining structural details of the mechanism disclosed in the schematic diagram of Fig. 1 will be described in connection with the description of operation which follows.

Assume that all the elements of the mechanism are in the position shown in Fig. 1, that the lower portion at least of the outer tubing 2 is submerged in well oil in the casing I, that the outer tubing 2 is connected at the surface to a discharge line for pumped oil, and that a substantially continuous stream of clean oil (hereinafter referred to as pressure oil) is forced down from the surface through the'inner tubing 3.

The pressure fluid from tubing 3 passes through longitudinal'passages 36 into the pocket 28 of the valve from which it is admitted through passages 3'! to the under side of the shoulder 20 on the traveling barrel, which shoulder constitutes the moving piston in the working chamber. 'It will be observed that at the same time the upper end of the working chamber above the shoulder which, with the valve 1 in lowermost position, is connected through exhaust passages to the space surrounding the stationary motor plunger and within the projecting upper end of the traveling barrel I9. This space within the upper end of the traveling barrel is vented to the outer tubing through ports 40 at the upper end of the barrel.

The traveling barrel thereupon moves upwardly, carrying with it the pump plunger 22. Movement of the pump plunger rod 2I upwardly through the block I2 displaces a quantity of oil in the outer tubing 2 in which the pump mechanism is submerged, forcing this oil upwardly to the surface through the tubing 2. At the same time the upward movement of the traveling motor barrel and pump plunger assembly 5 causes the cross head 34 to engage the cross head 33 on the auxiliary valve actuating rod I8, moving the latter upwardly and causing the rack 32 to rotate the pinion 3| in a counterclockwise direction, thereby forcing the rack 33 and the auxiliary valve 8 downwardly. The traveling motor barrel and pump plunger assembly 5 continue their upward movement and the auxiliary valve 8 continues its downward movement until the parts are in the relative position shown in Fig. 2. (It will be'observed that in Figs. 2, 3 and 4, the well casing I has been omitted to simplify the drawings).

With the parts in the position shown in Fig. 2, the central valve pocket 28, which is at all times supplied with pressure fluid from the inner tubing string 3 through the passages 36, is connected through passages 4I in the piston valve 1 with a passage 42 in the auxiliary valve 8, the opposite end of which passage communicates with the extreme lower end of the valve chest 8,'thereby applying pressure fluid to the under end of the piston valve 1. In the position of the parts shown in Fig. 2, the upper end ofthe valve chest G is connected by passages 43 in the auxiliary valve 8 and passages 44 in the piston valve with the upper pocket 21 of the piston valve, which pocket is also connected to the exhaust passage` 39 leading to the exterior of the plunger rod. As a result of the differential pressure betweenA the pressure fluid supplied through the inner tubing 3 and the pumped fluid and exhaust fluidin the outer tubing 2 applied to the piston valve 1, the latter moves upwardly into theiposition shown in Fig. 3.

With the parts'in the position shown in Fig. 3 pressure fluid from the valve pocket 28 is applied through passages 38 to the upper end of the working chamber above the shoulder 28, which constitutes the moving piston within the working chamber, and the lower end of the working chamber is connected through passages l1 to the lower valve pocket 25, which is connected through exhaust passages 46 to the space surrounding the plunger below the shoulder I1, from which space exhaust fluid is exhausted through ports 41 to the outer tubing 2 and thence up to the surface.

rI'he differential pressure acting upon the shoulder 28 thereupon forces the latter, together with the traveling motor barrel and pump plunger assembly 5, down into the position shown in Fig. 4.

During the preceding upward movement of the pump plunger 22 oil was drawn into the pump barrel I4 through the standing valve 25. Therefore, during the downward movement of the pump plunger 22 the uid previously drawn into the pump barrel is displaced upwardly past the' check valve 28 in the pump plunger through the hollow pump plunger and the ports 24 into the outer tubing 2. The area of the pump plunger rod 2l is preferably equal to half'the area of the plunger 22 so that equal quantities of pump iluid are discharged into the outer tubing 2 on both the up and `down strokes of the plunger.

Of course, as `the traveling motor barrel and pump plunger assembly 5 travel down into the position shown in Fig. 4, the auxiliary valve 8 was moved into its uppermost position. In this position pressure fluid is admitted from the pocket 28 in the valve 1 through passages 48 in the main valve and passage 49 in the auxiliary valve to the upper end of the valve chest, thereby applying pressure iluid to the upper end of the piston valve. At the same time the lower end of the valve chest is connected through passages 50 in the auxiliary valve and passages 8l in the main valve with the valve pocket 28, which is connected through passages 48 with the outer tubing. The piston valve 1 thereupon moves downwardly into the lowermost position in which all of the parts are positioned as shown in Fig. i, thereby completing a cycle of operation.

It is essential to the proper operation of a pump mechanism of the type described that the piston valve 1 substantially complete its movement before thetraveling barrel of the motor begins to move and it is also important that the valve thereafter remain in the end position to which it was last moved until the traveling barrel has completed its movement.

Completion of the movement of the piston valve before any appreciable movement of the traveling barrel is effected in the mechanism disclosed by virtue of the-fact that the pressure of the operating duid required to shift the piston valve is less than that required to shift the traveling barrel. 'I'hus the upper and lower faces of the piston valve are of equal areas so that the differential pressure required to shift the piston valve is only that necessary to overcome the friction between the sliding parts. On the other hand, a greater differential pressure between the operating fluid supplied through the inner tubing 3 and the exhau-t fluid and pump fluid discharged through the tubing 2 is required to shift the traveling barrel because movement of the latter is not only opposed by the pressure of the exhaust fluid acting against the end of shoulder 20 (the area of both ends of which are the same) but also by the pressure of theY exhaust fluid acting against the pump plunger. In other words, the exhaust fluid is always exerting its pressure against an area on the traveling motor barrel and pump plunger assembly that is larger than the area to which pressure fluid is applied, whereas the surfaces of the piston valve exposed to pressure fluid and exhaust fluid, re Vpectively, are'always equal.

After having been once moved to an end position, the piston valve is urged to remain in that position not only because of the pressure fluid trapped in the opposite end of the valve chest but also by virtue of the fact that the auxiliary valve 8 is moved, during the major portion of the movement of the traveling barrel, in a direction tending to maintain the piston valve in the end position to which it was last shifted. Thus, in Fig, l the piston valve 1 is in lowermost position and during the upward movement of the traveling barrel into the position shown in Pig. 2 the auxiliary valve 8 is moved downwardly, thereby tending to maintain the piston valve in its lowermost position. Similarly, during the sequence of operations occurring between the positions indicated in Figs. 3 and 4, the piston valve is urged upwardly, thereby tending' to maintain it in its upper position, by the upward movement of the auxiliary valve. i

'I'he schematic diagrams of Figs. 1 to 4 are provided principally to illustrate the principles of operation and make it easier to understand the construction and operation o fnthe practical pump illustrated in Figs. 5 to; 18v in which, because oi' the fact that diametrical space is at a premium, a pumping capacity suicient to make the unit practicable is obtained by making the stroke of the traveling motor barrel and pump plunger assembly, and the over all length of the unit, much greater in proportion to the diameter of the unit than is shown in the schematic diagrams of Figs. 1 to 4. It is also to be noted at this point that the practicable pump to be described incorporates many structural features which in the interests of clarity are omitted from the schematic diagrams although many of these features in themselves involve invention.

However, the schematic diagrams of Figs. 1 to 4 illustrate some of the advantages of that feature of my construction consisting in the Vmounting of the motor valve mechanism vwithin of Fig. 1 that my construction provides relatively short straight passages between the valve chest and the-two ends of the working chamber and between the' valve chest and the exhaust passages surrounding the plunger member above and below the working chamber. My construction also reduces the length of the pressure iluid conduits (passages 36) connecting the inner tubing with the valve chest and reduces the pressure drop in those passages. It should be noted particularly that in my construction only a single passage for conveying iluid (the fluid discharged from the pump intermingled with motor exhaust fluid from the passages 46) upwardly past the motor, is necessary; therefore, the entire annular space between the motor barrel I9 and the outer tubing 2 can be used for this purpose.

Construction of practicable pump as illustrated in Figs. 5 to 18 The outer tubing assembly That portion of the outer tubing 2 immediately above the pump is joined by a nipple 52 (Fig. 5) to a coupling 53. As shown in the drawings, the nipple 52 is expanded at its lower end and interiorly threaded to screw onto an exteriorly threaded portion of the coupling 53. The exterior diameter of the lower -portion of the nipple 52 and of coupling 53 is slightly greater than the body of the tubing 2 (not shown' in Fig. 5) and the upper end of nipple 52, but is of sub- `to accommodate the outer tubing itself. The

coupling 53 projects inwardly beyond the inner surface of the lower enlarged portion of the nipple 52 and constitutes a guide for the member 10 to be described later. The upper edge 53a of the coupling 53 constitutes a shoulder for supporting a skirt 13 to be described later.

Threaded onto the lower end of coupling 53 is a sleeve 54 which extends downwardly (Figs. 5, 6, 7, 8, 9 and 10) to a point immediately above the pump portion of the unit where it is threaded onto a pump supporting coupling 55. Attached to the lower end of the pump supporting coupling 55 and extending downwardly therebelow is another sleeve 56 (Figs. 10, 11 and l2) extending substantially to the lower end of the unit, where it is threaded onto a gas anchor coupling 5l. The anchor coupling 51 is adapted t'o have screwed thereinto an upper end of any standard gas anchor for separating gas from the oil before it enters the pump barrel.

The stationary motor plunger and pump barrel assembly Referring first to Fig. 10, the stationary motor plunger and pump barrel assembly, which is directly supported from the pump supporting coupling 55, comprises a hollow stem 58 having a beveled face 59 which rests against and seals with a complementary face on the upper end of coupling 55. The hollow stem 58 together with the coupling 55 constitute the elements defining a partition in the outer tubing to permit the portion of the outer tubing thereabove to be used as a discharge passage for oil to the surface while the portion of the outer tubing therebelow contains well-oil at relatively low pressure.

Threaded onto the upper end of the hollow stem 58 is a supporting column 60, which is of tubular construction but privided with diametrically opposite longitudinal slots Gila serving as guides for the cross head to which the traveling barrel is attached. The supporting column i@ extends upwardly (Figs. 10 and 9) and is connected at its upper end by screw threads to the lower end of a, nipple 6|, which constitutes the housing for the auxiliary valve motion reversing -mechanism. The nipple Si is attached at its upper end by screw threads to a block 52 constituting the lower end closure wall of the valve chest 6. Block 62 is connected at its upper end to the lower end of .a sleeve 63 defining the lower portion of the valve chest and also the lower shoulder of the motor plunger that seals with the traveling barrel and closes the lower end of the working chamber. To this end packing rings 64 are provided on the exterior of sleeve 63 to eifectively seal with the traveling barrel. The passages 46 for communicating the valve chest with the exterior of the plunger rod below the working chamber and the passages 3l for communicating the valve chest with the lower end of the working chamber are formed in the sleeve 63.

At its upper end the sleeve G3 is joined by screw threads to a sleeve 65, which constitutes that portion of the plunger rod of the motor which defines the inner wall of the annular working chamber and also the mid portion of the valve chest.

Sleeve 65 is attached by screw threads atits upper end to the lower end of a sleeve 5B which dennes the upper portion of the valve chest and also the upper shoulder of the motor plunger that seals with the traveling barrel and closes the upper end of the working chamber. Sleeve 66 is provided with packing rings 61 (Figs. 7 and 6) for sealing with the traveling-barrel andcon- `tains the passages 38 for communicating the valve chest with the upper end of the `working chamber. and exhaust passages 39 for communicating the upper pocket 21 of the valve with the outer tubing.

Sleeve 66 is connected at its upper end by screw 'threads to a block 68 constituting the upper end closure wall of the valve chest. Sleeve 66 and block 68 contain the longitudial passages 36 for connecting the Valve chest to the upper end of the stationary plunger rodrwhichis exposed tothe pressure fluid delivered through the inner tubing. These passagesterminate, at the upper end of sleeve B andthe lower end of block |50,` in annular passageways 35a to provide free fluid connection between those portions of the passages 36 in the twoblocks regardless oi' whether or not they are aligned with each other. i

The block 68 constitutes a guide for the upper end of the auxiliary valve 8 and is therefore provided with ventports 68a for connecting the upper end of the auxiliary valve guide channel "to the space within the outer tubing sleeve 54 which is filled with exhaust and pumped fluid.

The upper end of block 68 is threaded into the lower endof a sleeve 69, which in turn is threaded at its upper end into the lower end of a coupling 'I0 which has attached thereto at its upper end a deflecting cone ll for spreading the skirt 'I3 in a manner to be described later.

As shown in the schematic diagrams of Figs. l to 4, the inner tubing 3 is solidly attached to and supported from the stationary plunger assembly 4 of the pump. Such construction would be undesirable in practice as the relatively enormous weight of the inner tubing might produce severe stresses in the pump plunger which would distort it and prevent satisfactory operation. For this reason ythe expansible skirt 13 (Fig. 5)` is provided for directly supporting the weight of the inner tubing from the coupling 53 in the outer tubing and a sliding but fluid-tight connection is provided between the coupling 10 `on the lower end of the inner tubing 3 and the upper end of the stationary plunger assembly, which upper end is constituted by the coupling 12 and deflecting cone 1l in Fig. 5. The coupling member 12 on the lower end of the inner tubing 3 is therefore provided with an inner downwardly extending sleeve 14 which passes downwardly through the deflecting cone 'H and is sealed therewith by packing members lla. The sleeve 14 is provided with a shoulder 14h thereon for limiting upward movement of the sleeve 14 with respect to the cone 1| constituting the upper end-of thestationary motor plunger assembly. However, downward movement of the sleeve 14 is limited only by engagement of the skirt/13 on the coupling 12 with the shoulder 53a on coupling 53 in the outer tubing so that `the entire weight of the inner tubing 3 is borne by the coupling 53 whereas the entire weight of the stationary motor plunger and pumpbarrel assembly is borne by the outer tubing through the lower coupling 44 (Fig. 10).

The lower end of the sleeve 14 is provided with perforations 14o therein, permitting high pressure fluid to pass from sleeve 'i4 into the surrounding space within the coupling 10 and the sleeve 69, from which point it is free to` pass down into the hollow upper end of block 68 and thence through the passages 36 to the valve chest.

The lower endof sleeve 14 is closed by a bush- 'ing l5, which'snugly engages a vplug rod 10 having an enlarged head 16a on the lower end there- 'of which seals a vent 68h provided in the upper end of block 60. The rod 16 is provided on its upper and with a nutlllib so that when the sleeve 14 is elevated by lifting the inner tubing string 3; in the process of removing the pump from the well, the bushing 15 engages the nut lib on the plug rod 16 and lifts the head 16a clear of the aperture 60h, thereby permitting fluid standing 'in the inner tubing 3 -to drain out through the ports 60a into the outer tubing.`

` Auxiliary valve The auxiliary valve 8, which is shown constructed in one piece in the schematic diagrams of Figs. 1 to 4, is in the practicable pump illustrated in Figs. 5 to 18 made in several parts. Thus the upper end of the auxiliary valve is shown in Figs. 6 and '7 as comprising a rod 00 having the grooves 43 and the centrall passage 49 therein. This rod 80 is joined at its lower end by screw threads to a rod 8| (Figs. 7 and'8) constituting the'central portion of the auxiliary valve and winch in turn is joined by screw threads at its lower end to the upper end of a rod 82 having the passage 42 and the grooves 50 therein.

The lower end of the rod 82 projects through the block $2 dening the `lower end of the valve chest (Fig. 9) and is provided with an annular groove 82a in its projecting lower end. which interlocks with a shoulder 83 on the upper end of the rack 30, which engages with the pinion 3|. The pinion 3l, as previously mentioned, is rotatably supported in the nipple 6I and also meshes with the rack 32. `The latter is provided with a shoulder 84 on its lower end whichengages with an annular groove'll` in the upper end of the auxiliary valve actuating rod l0. `The racks 30 and 32 are supported for free longitudinal movement within the nipple 6l by providing grooves in the nipple for receiving the racks, as shown clearly in the cross section of Fig. 15.

The stroke of the auxiliary valve and of the auxiliary valve actuating rod I0 is much less than the strokeof the traveling barrel, the auxiliary valve being shifted during only the last portion of each stroke of the traveling barrel. In order to maintain the auxiliary valve in each end stroke position until it is positively displaced therefrom by the next movement of the traveling barrel in the opposite direction, the rod i0 is provided with grooves |0a containing expansible rings I0b which expand into recesses l0c and l0d in the upper end of the supporting column 60 when the rod I 0 is in its lowermost and its uppermost positions, respectively. The force of `the rings I0b is sufllcient to retain the rod I0 in the end stroke position into which it was last moved but is not sufilcient to prevent the rodbeing moved when positively shifted by the traveling barrel. e

l The cross head 33 on the lower end of the actuating rod l0 is constituted by a metal block extending crosswise through an aperture provided therefor in the lower end of rod l0, the ends of this block 33 fitting in guideways provided therefor in the traveling barrel to be described later. Thus 'the adjacent portion |00 of the traveling barrel is provided with groovesfor receiving the ends of the cross head 33, the length ofthe grooves being equal to the difference between the stroke of the traveling barrel and the stroke ofthe auxillary valve so that the auxiliary valve will `be shifted into anew end position only during the latter portion of each stroke of the traveling barrel. InA the drawings lboth the` traveling barrel and the auxiliary valve are shown in lowermost position in which the ends of the cross head 33 have been engaged by the shoulders at the upper ends of the guide channels or grooves |00. 1 On Construction of: the piston valve The piston valve 1 is constructed in three parts. Thus it comprises an upper member 86 which seals about the rod and is yprovided with an upper shoulder 81 (Fig. 6) and a' lower shoulder 88 (Fig. 7) which seal with the .wall of the valve chest and define therebetween the upper valve pocket 21. The member 81 is joined at its lower end to the upper end of a sleeve member 89 which contacts neither with the ad,- jacent portion 6| of the auxiliary valve nor the walls of the valve chest, and is provided with perforations 89a to permit free passage of iluid therethrough.l The sleeve member 89 isprovided with a shoulder 89b immediately below the perforations 89a and `detent rings 89e are preferably provided on the shoulder 89h to provide a yieldable mechanical locking mechanism tending to retain the piston valve in its'uppermost position after having once been moved into that position. As vshown in Fig. 7, .the piston y'valve is in its lowermost position, in which the detent rings 89e are substantially completely pressed within the shoulder 89h. However, when the valve is moved into its uppermost position the detent rings 89e rise slightly above a shoulder 65a in the sleeve 65 constituting the adjacent portion of the valve chest wall. The detent rings thereupon expand and, when the valve tends to return, the rings bear against the shouder 65a and tend to resist such return. However, when pressure iluid is applied to the end of the piston valve the force applied to the valve is relatively great as comparedv to the resistance to motion produced by the detent rings 89o and the latter compress and permit the valve to move downwardly. For a substantial distance below the shoulder 89h the member 89 is imperforate and cylindrical in shape and of such dimensions that it contacts neither the auxiliary valve nor the walls of the valve chest. At the lower end of this portion there is provided another shoulder 90 (Fig. 8) having detent rings 90a thereon for engaging below a shoulder 650 in the sleeve 65 whenl the valve is in lowermost position. These detent rings 90a function to yieldably retain the valve in lowermost position in exactly the same manner as the detent rings 89e tend to maintain it in its upper position. A small section of member '89 below the shoulder 90 is provided with perforations 9| to permit free passage of iluid therethrough. The lower end of the sleeve member 89 is attached by screw threads to a member 92 corresponding to the upper valvemember 86 having upper and lower shoulders 93 and 94, respectively.. which seal with the walls of the valve chest and dene the valve pocket 29. l

tween the two resides in the fact that the valve has been greatly elongated in the practical modiiication by, in effect, breaking it at the middle and interconnecting the two parts with the sleeve member 89. f l

The traveling motor barrel As has been previously explained, the traveling barrel of the motor is rigidly connected to and reciprocates the pump plunger. Referring iirst to Fig. 10, the upper end of the pump plunger rod 95 is screwed onto a downwardly depending stub shaft 96 on a cylindrical member 91 which is solidly attached to a cross head 98, which extends through an orifice provided therefor in the member 91. The outer ends of cross head 98 extend through and are ilush with the outer surface Vof a collar 99, which is screwed into the lower end of a tubular member |00, constituting the lower section of the traveling barrel. At its upper end the tubular member |00 (Fig. 8) is threadedonto a coupling |0|, which coupling is ground to seal with the adjacent portion 85 oi the stationary plunger rod. The coupling member |0| therefore constitutes the piston element of the motor which divides the working chamber into two parts. It will be observed that the tubular member |00 seals with the packing rings 64 on the sleeve 63 which denes the lower end of the working chamber of the motor.

'I'he coupling member |0| is joined at its upper end by screw threads to a tubular member |02 constituting the upper portion of the traveling barrel,r this portion sealing with packing rings 61 on the sleeve 66 dening the upper end of the working chamber, and extending upwardly therebeyond a substantial distance, as shown in Fig. 6. This upper section of member |02 is provided with apertures |02a to provide free flow of iluid from the exhaust passages 39 and the passages 68a. A collar |03 is provided on the upper end of the tubular member |02 which slides along the sleeve 69 and acts as a guide for the upper end of the traveling barrel.

Pump unit Referring to Figs. 10 and 11, the upper end of the pump barrel comprises a tubular member 05 threaded into they lower end of the hollow stem 58, which seats within the pump supporting coupling 55. Packing rings |05a are preferably provided to form a seal between the barrel memb'er |05 and the upper end of the pump plunger rod 95.

The barrel proper of the pump is constituted by a sleeve 06 screwed onto the lower end of the tubular member |05. The sleeve, |06 is provided with ports |06a therethrough to permit fluid from the well to surge in and out of the upper end of the barrel as the plunger reciprocates. The lower end of the sleeve |06, constituting the pump barrel, terminates (Fig. 12) in a coupling |01' which serves to secure in position in the lower end of the sleeve |06 a standing valve seat |08 and valve cage |09, within which the ball valve 23 is positioned. 'I'he lower end of the coupling |01 is threaded to receive an oil .inlet pipe (not shown) extending downwardly into the well.

The pump plunger assembly comprises the hollow plunger rod 95 (Fig. 10) previously menplunger proper which seals with the pump bar-1 rel |25. `Thus the cylindrical member ||4 is supported between a shoulder I I3a on member'l I3 and the lower endrof the coupling *membery I I2. The cylindrical member i I5 is similarly support ed between a shoulder I|3b on member ||3 and a coupling member IIB screwed onto the lower end of member I I3. The coupling members ||I and |I2` lserve to support therebetween a valve seat cooperating'with a ball valve YI I8, and 'a'. member III positioned belowl the coupling member l" and a bushing '(the lather constituting the extreme lower end of the pump plunger) serve to retain a second valve seat I2| which co-f operates with a ball valve |22; The two valves, including balls III and I22, together function the same as the single valve ball. 23 vshown'jin the schematic drawings of Figs. l to 4to permit entry of fluid compressed below the pump plunger up through u the hollowv plunger rod,` vbut prevent its return. The fluid flowing upthrough the hollow plungerorod escapes to the outer tubing through ports 24 (Fig. 10) `in the upper end of the hollow pump plunger rod.

Traveling barrel Iockinmmechanisrn Pumps of the generaltype to which this invention relates vdependfor their properoperation on definite sequential movements of the different parts. Should the different parts, such as the traveling barrel assembly, the piston .valve and the auxiliary valve, be accidentally initially placed'in certain relative positions, they might fail tooperate in response tothe application of pressure fluid thereto. I therefore provide a special locking mechanism for maintaining the traveling barrel assembly in lowermost position while the device is in transit and is being lowered into the well with means for automatically unlocking the traveling barrel assemblyafter inf stallation in the well. Referring to Fig. 10, the locking mechanism therein disclosed comprises a detent ball |23- positioned in a passageway- |24 in the block 55, the length of the passagewayulu lbeing slightly less than the `diameterof the detent ball |23 and the outer edge ofthe passageway being normally closed by a plunger |25 fitted in a vertical cylindrical passage |25 in theblock 58. `The upper end of passage |25 opens .into the outer tubing above the sealing surface 59 on block 58 and the lower end of the passage opens toI the exterior below the sealing surface'58-` The plunger -|25 is normally retained in uppermost position by a helical spring |21` positionedthere'belovlh in which position the detent ball I23'is forced inwardly beyond the inner surface of the block 58' and into engagement with a portion |28 of the pump plunger 55, which'is of reduced diameter. ,It will be apparent that so long as'plunger |25 is`in the uppermost position shownin Fig.`l0, any upward movement of the pump plunger 95 and the travel-` ing barrel assembly connected thereto willbe prevented by engagement of the detent ball |23` force of the helical 'spring f|2`| and move the plunger downwardly until a' recess |23 therein is juxtaposed' to the detent'ball |23; permitting the latter to move outwardlyaway from thepump plunger rod 55. f y

The differential pressure necessary to move the plunger |25 is `produced when the pump, after being seated in the well with thebeveled face `53 resting againstand sealingrwith the cooperating face on the pump supporting coupling 55, is conditioned for service by filling the outer tubing 2 with oil. As soon as any appreciable head of oil has been built up within the outer tubing,the pressure ofthe oil on the upper end of plunger |25 is sutilcient to depress'the latter to release the detent ball |23 and permit the reciprocation of the traveling motor barrel and pump'plunger assembly. o

A modified formof lock is shown in Fig. 10A, which shows a section of a completed pump correspondingin general to that disclosed in Fig. l0 and corresponding parts offwhich bear correspending reference numerals with the prime mark sulxed. The essential difference betweenv the locking mechanism disclosed in Fig. 10A over that disclosed in Fig. 10 is that whereas the ball detent is released in Fig. 10 by the application of fluid pressure, the detents `in Fig. 10A are automatical- `ly released in response to the seating of the pump.

Thus the'detent balls |23' positioned in es |24.' in the block 58" are, before the pump is installed, forced in'to engagement with the reduced portion |2' of thepump plunger'rod 55' by a skirt member |29 which is forced downwardly by a helical spring |30 positioned thereabove tov bring the upper reduced portion ISI of the skirt juxtaposed to the outer ends of the passages |24'. The skirt member |29 in this modification constitutes the member which seats against the pump supporting coupling 55` and is provided'with a beveled face 59' for this purpose. The skirt member is also slidable vertically alongthe hollow stem 55 but has its vertical movement limited by a shoulder |32 through which, when the pump has been seated, the entire weight and all downward force exerted on the pump are-transmitted to the skirt Amember |29 and thence V.to the pump supporting coupling 55'. It willbe observed that as soon as the pump has been`j seated; as shown inv Construction of joints between` sections As described, my practical `pump is made up of many `different ytubular or. cylindrical parte joined together by screw threads. In many instances. adjacent parts u V that mustbe concentricwith respect to each other. Thus, for, example, consider the joint between the tubular block 52V (Fig. 8) and the sleeve 63 thereabove, in ,which the bore of the block must be very accurately aligned with the bore of the sleeve if the auxiliaryvalve and main valve are to move freely and also seal with eachother and with the bores of the block 52 andsleeve; respectively. Heretoforeyin order to closely iit such parts, it has .o been `considered. necessary eitherto cut the threads exactly concentric with the bores, or to drill or ream the bores` oi' the parts after they have been screwed together.

have. bearing surfaces Both methods are expensive andI avoid them by using square threads4 to join the parts instead of the conventional V-threads, and aligning the parts with a mandrel while they are being s'crewed together. This method, as applied to the joint between block 62 and sleeve 63 is illustrated in Fig. v19, in which the square threads on the sleeve 63 areA indicatedat 63a, the square threads on the` blockl 62 are indicated at 62a; and the aligning mandrel indicated in dotted lines at |40. 'Ihe square threads 62a and 63a. are so deep that they permit substantial lateral movement between the two parts and donot determine their alignment, merely serving to clamp the parts firmly together while they are maintainedin alignment by the mandrel |40. After the joint is made and the mandrel |40 is removed, the parts remain in alignment because of the friction between the threads and between the abutting shoulders of the parts, andbecause the square threads exert no lateral force tending to produce a lateral shift. It is to be noted that this method of joining. parts with their cylindrical bearingsurfaces in alignment cannot be used with V-threads because the latter are inherently self-centering, whereas square threads are not.

The method, although illustrated in detail only with reference to the` joint between block 62 and sleeve 53, is applicable to all the screw joints in the pump between parts having cylindrical surfaces that must be accurately aligned, the shape and dimensions of the mandrel employed with each joint depending, of. course, on the shapes and dimensions of the surfaces to be aligned. Thus where the surfaces to be aligned are outer surfaces instead of inner surfaces, the mandrel must surround the parts and in some such instances the mandrel may be split to facilitate its removal.

Installation and removal of the pump At the time of the original installation of a pump as described, the outer tubing 2 before being lowered into the well has attached thereto on its lower end the nipple 52, coupling 53, sleeve 54, pump supporting coupling 55, sleeve 56, and the anchor coupling 51,"as disclosed in Figs. 5 to 12, inclusive. "Thereafter the pump unit is attached to the lower ond of the inner tubing string 3 and is later lowered down through the outer tubing 2.

While supported from the lower end of the inner tubing string 3, all portions of the pump unit are sufciently small to pass freely through the outer tubing'. Thus at this time the sleeve 14 attached to the coupling 12 (Fig. 5) instead of being in the position shown in the drawings, would be withdrawn until the shoulders 'Mb rested against the lower end of the packing members 1|a, the weight of the entire unit being supported by the shoulder 14h. In this position the expansible split skirt 13 on the coupling 12 is in its normal position in which it is substantially cylindrical in shape and of the same outside diameter as the main portion of the coupling 12.

As the assembly supported on the inner tubing string 3 approaches the lower end of the outer tubing 2, the tubular member |05 defining the pump barrel enters the pump supporting coupling 55 and passes downwardly therethrough until the beveled face 59 seats against the upper end of coupling 55 (Fig. 10). Thereafter continued downward movement of the inner tubing string causes the sleeve 14 to telescope within the deflecting cone 1|, thereby expanding the split skirt 13 until the lower edgev of the latter rests againstthe shoulder 53a on the coupling 53 (Fig. 5). Thereupon the weight of the inner tubing is supported through the skirt 13 by the coupling 53.

The pump parts are so dimensioned that shortly after the beveled face 59 of the hollow stem 58 (Fig. 10) seats against the pump supDOrting coupling 55, the enlarged head 16a (Fig. 6) seats in'the port 68h which communicates the ports 68a with the outer tubing.

The pump is then set in operation by lling the outer tubing with oil to create sufficient pressure to actuate the plunger |25 (Fig. 10) and release the detentball |23 to permit reciprocation of the traveling motor barrel and pump plunger assembly. Thereafter the inner tubing string 3 is 4filled with pressure Afluid and a continuous stream of pressure fluid is forced therethrough to operate the pump in the manner described with reference to the schematic drawings of Figs. 1 to 4. It will be observed that when the inner tubing string is filled with liquid under pressure the enlarged plunger head 16a (Fig. 6) is maintained tightly seated by the pressure of the fluid thereabove.

The installation and operationof a pump having a locking mechanism as disclosed in Fig. 10A is identical with that described except that it is unnecessary to ll the outer tubing with oil preliminary to starting the pump since the 4detent balls |23 are automatically released when the pump is seated.

If for any reason it becomes necessary to remove the pump from the well after it has been in operation, such removal is accomplished by simply disconnecting the supply of pressure fluid from the inner tubing string 3 at the surface of the well and pulling the inner string. Initial upward movement of the inner tubing string 3 elevates the coupling 12 (Fig. 5), lifting the split skirt 13 away from the deflectng cone 1| and the shoulder 53a, permitting the latter to contract to the diameter of the upper or main portion of the coupling 12. Thereafter continued upward movement first causes the bushing 15 (Fig. 2) in the lower end of the sleeve 14 to engage the nut 1Gb on the upper end of the plug rod 16 and lift the enlarged head 16a clear of the opening 68h which it lnormally closes. This permits the oil standing in the inner tubing string to drain out through the opening 68h and the ports 68a into the outer tubing as the inner tubing and the pump are withdrawn, thereby permitting what is termed a dry job of pulling. Of course, further upward movement Aof the inner tubing string causes the shoulder 14h cn the sleeve 14 to engage with the under edge of the packing member Ha following which further upward movement of the inner tubing string carries the pump up throughthe outer tubing string 2 to the surface.

After theA pump has been removed from the well, it will be observed from Fig. 10 that the motor end of the pump may be completely detached from the pump end by breaking the threaded vconnection between the hollow stem 58 and the supporting column 60 and the threaded connection between the upper end of the pump plunger rod and the stud shaft 96 on the cylindricalmember 91. This feature, whereby the pump unit -may be readily removed from the motor unit, is very important for the reas'on fact that the pump must with clean filtered oil from enclosed piston or plunger even though the that a pump unit is apt to wear much more rapidly than the motor unit by reason of the handle oil from the well containing sand and other abrasive material whereas the motor unit can be supplied the surface.

The ready separation of the pump and motor units is also desirable in that it permits `ready substitution of pump units of different capacities, thereby permitting the use of the same motor in wells of different depths without increasing the pressure of the operating fluid supplied to the motor in the deeper well by merely employing a pumping unit of smaller capacity in the deep well than inthe shallow well.

It should also be noted that, by virtue of the fact that the motor end of the pump is fully enclosed and constantly fioodediwith filtered oil from the inner tubing 3, no bearing surface of the mechanism 'in the motor unit comes in contact with the pumped fluid.

Of course, as previously mentioned, probably the greatest single advantage of my construction is that the use` of the traveling motor barrel and stationary plunger assembly with the valve mechanism positioned within the plunger rod eliminates many restricted passages and irregular passages having right angle turns therein, thereby decreasing fluid friction and adding to the mechanical emciency of the unit. I'Ihis advantage can best be emphasized by comparison. Thus I am able to obtain an equal or greater pumping capacity with an assembly of the type described having an over all diameter of only 2 and sths inches than was formerly obtained with a pump having an over all diameter of 4 inches.

`A substantial advantage results in my construction from the fact that both the traveling motor barrel and stationary motor plunger are supported from their lower ends and the inner tubing string is supported independently of the stationary plunger assembly, thereby eliminating unnecessary compression or tension strains in the plunger and barrel assemblies which might i cause them to warp and freeze when installed in the well. The free-end barrel is less rigid and will flex enough to align itself with the bore of the barrel may be off center a few thousandths of an inch or may not be absolutely straight.v

` The use of the automatic lock for the traveling barrel is a very desirable feature in that it makes the pump substantially fool-proof even when installed and operated by unskilled labor. The use of the expansible skirt for supporting the weight of the inner tubing from the outer l tubing independently of the pump mechanism also tends to make the device more fool-proof as it prevents any possible damage to the mechanism resulting from too rapid landing of the pump in the'bottom of the tubing by a careless well crew.

Although, as previously stated, the motor unit is preferably suppliedwith clean filtered oil through the inner tubing string '3, the tubing itself often contains a certain amount of dirt, scale, sediment, etc., which it is desirable to keep out of the motor parts. Such deposits are prevented in large measure from reaching the working parts of the motor by the sleeve 'Il (Figs.

5 and 6) having the perforations Nc therein, These perforations filter the oil to a. certain extent and ,the tube also acts as a sort of a. trap, heavy foreign particles in the oil therein tending to settle to the bottom of the sleeve Il about the plunger rod 18 instead of passing out through the perforations Tlc.

Although the invention has/been described with reference to a particular embodiment thereof to simplify the conveying of a full understanding `of the essential principles involved, it is to be understood that the invention is not limited to the specific structures shown but instead isto be limited only as set forth in the appended claims.

1. In a fluid-actuated Well pump adapted to be positioned in a well and having pressure uid and exhaust fluid connection with the surface through separate conduits, a reciprocating pump unit having astationary element and a reciprocating element, a motor unit comprising a stationary plunger assembly adapted to be connected to the stationary element of the reciprocating pump unit,

and a cooperating reciprocable cylinder assembly adapted to becoupled tothe reciprocating element of the pump unit and defining together with Isaid plunger assembly a working chamber having a reciprocable piston element therein, valve means for said motor unit incorporated within said stationary plunger assembly for controlling the admission of pressure iiuid to and the discharge of exhaust fluid from opposite ends of said working chamber, said plunger assembly also defining uid passages extending directlyfrom said valve means to said working chamber and from said valve means to said pressure fluid and exhaust uid conduits, respectively, and means for actuating said valve means in response to'predetermined movements of said cylinder assembly.

2. In a huid-actuated well pump adapted to be positioned in a well and having fluid connection with the surface through an outer tubing for the discharge of exhaust fluid and pumped fluid and separate fluid connection with the surface through a. smaller inner tubing positioned within the outer tubing for the reception of operating fluid under high pressure, a motor unit comprising a stationary plunger assembly and a cooperating reciprocable cylinder assembly adapted to be submerged in exhaust and pumped uid within said `outer tubing and defining between them a working chamber, a reciprocable piston elementin said chamber, valve means incorporated within said stationary plunger assembly for controlling the admission of pressure ud to and the discharge of exhaust fluid from the opposite ends of said working chamber, said plunger assembly also defining fluid passages extending directly therethrough from said valve means to said working chamber and from said valve means to the duid surrounding said unit within said outer tubing, and to said inner tubing, respectively, means for actuating said valve means in response to predetermined' movements of said cylinder assembly, a pump unit, and means for actuating said pump unit in response to reciprocation of said cylinder assembly.

3. In a fluid-actuated well pump adapted to be positioned in a with the surface through an outer tubing for the discharge of exhaust nuid and pumped fluid, and

well and having fluid connection.

' Y having chambers therein said chamber, said unit being adapted to be submerged in uid in said outer tubing and positioned below the lower end of said inner tubing, said plunger member having a cavity therein constituting a valve chest, a reciprocable valve in said valve chest, means forming a iluid connection between said inner tubing and the upper end of said plunger member, an operating uid inlet port in said valve chest and a passage in said plunger member connecting said inlet port with said end of said plunger member, exhaust ports in said valve chest and passages extending through said plunger member for connecting said exhaust ports with the exterior of said member in communication with the fluid in which said unit is submerged within said outer-tubing, other ports in said valve chest and passages in said plunger member communicating said other ports with the opposite ends of said working chamber, said reciprocable valv'e for selectively interconnecting said inlet and exhaust ports with said other ports to supply operating duid to either end of and to exhaust fluid from the other end of said Working chambe:` depending upon the position of said valve, and means for shifting said valve in response to predetermined movement of said traveling cylinder, a pump unit, and means for actuating said pump unit in response to reciprocation of said cylinder assembly.

4. In a uuid-actuated Well pump adapted to be positioned within a well and having iiuid connection with the surface through an outer tubing for the discharge of exhaust uid and pumped fluid 'and separate uid connection with the surface through a smaller inner tubing positioned within the outer tubing for the reception of operating fluid under high pressure, a motor unit adapted to be submerged in fluid within said outer tubing and comprising a stationary plunger assembly and a cooperating reciprocable cylinder assembly, the two defining therebetween a. working chamber, a piston element reciprocable in said chamber, said plunger assembly comprising an elongated plunger member having a cavity therein constituting a valve chest, valve means incorporated within said valve chest comprising a reciprocable valve rod extending through said chest and projecting therebelow and a uid operated piston valve positioned concentrically about said valve rod and having a sliding sealing t within said valve chest and about said valve rod, an inlet port in said chest and a passage in said plunger member communicating said inlet port with the upper end of said plunger' member, means communicating the upper end of said plunger member with said inner tubing, an exhaust port in said chest and a passage through said plunger member communicating said exhaust port with the surface of the plunger member at a point therein positioned beyond said working chamber and exposed to the iiuid in which said unit is submerged, other ports in said valve chest and other passages in said plunger member communicating said other ports with the surf-ace of said plunger member at points positioned within and adjacent opposite ends of said working chamber, said piston valve having chambers therein for selectively communicating said inlet and exhaust ports with said other ports to supply operating fluid to either end of said working chamber and to exhaust fluid from the opposite end of said working chamber when said valve is in predetermined positions in said valve chest, said valve rod having passages therein terminating in ports registering, respectively, with said valve chambers and with opposite ends of said piston valve when said rod is in predetermined positions for admitting pressure fluid to ,one end and exhausting uid from the opposite end of said piston valve to shift the latter, and means for reciprocating said valve rod in response to predetermined movement of said traveling cylinder assembly, a pump unit, and means for actuating said pump unit in response to reciprocation of said cylinder assembly.

5. In a fluid-actuated well pump adapted to be positioned within a Well and having fluid connection with the surface through an outer tubing for the discharge of exhaust fluid and pumped iiuid and separate uid connection with the surface through a smaller inner tubing positioned Within the outer tubing for the reception of operating fluid under high pressure, a motor unit comprising a reciprocable cylinder and a cooperating stationary plunger member positioned within said cylinder, said plunger member having longitudinally spaced shoulders sealing with said cylinder and constituting the end walls .of the working chamber of the motor and said cylinder having a shoulder thereon sealing with said plunger member and constituting the reciprocable piston within said Working chamber, said plunger member having a cavity therein approximately coextensive with said Working chamber constituting a valve chest, exhaust ports in said valve chest adjacent opposite ends thereof and exhaust passages in said plunger member extending directly therethrough from said exhaust ports to the exterior of said plunger member at points beyond said shoulders thereon for discharging exhaust fluid from said chest, an inlet port in said Achest adjacent the center thereof and a passage extending longitudinally through said plunger member from said inlet port to the upper end of said plunger member, means for applying pressure fluid from said inner tubing to the upper end of said plunger member, other ports in said valve chest positioned between and adjacent to said respective exhaust ports, passages extending directly through said plunger member from said other ports to the exterior of said plunger member at points between and adjacent said shoulders thereon for communicating said valve chest with opposite ends of said Working chamber, a valve reciprocable in said valve chest and sealing with the walls of said chest and having pockets therein for communicating one of said passages extending vto one end of said working chamber with either said inlet port or the adjacent exhaust port and communicating the passage extending to the opposite end of the working chamber either with the exhaust port adjacent thereto or said inlet port, depending upon the position of said valve in said chest, and means for reciprocating said valve in response to predetermined movements of said reciprocable cylinder assembly, a pump unit, and means for actuating said pump unit in response to reciprocation of said cylinder assembly.

6. In a uuid-actuated well pump adapted to be positioned in a well and having uid connection with the surface through an outer tubing for the discharge of exhaust fluid and pumped fluid and separate fluid connection to the surface through a smaller inner tubing positioned within the outer tubing for the reception of operating fluid under high pressure, a motor unit comprising a reciprocable cylinder member and a cooperating stationary plunger member positioned within the cylinder member and dening with said cylinder member an annular working Chamber having an annular piston element reciprocable between opposite ends, plgsaid workextending from ports in said valve Vchest through said plunger member to opposite ends of said working chamber for supplying pressure iluid`t0 either end of said working chamber and exhaust fluid from the opposite' end of said working chamber, an inlet port in said valve chest and a passageextending through said plunger member from said inlet port tothe upper end thereof for communicating said portwith said inner tubing, exhaust ports in said' valve chest-and passages extending therefrom through `said plunger member to the exterior thereof and into communication with fluid within said outer tubing, an annular piston valve in said valve chest -reciprocable in said chest and having pockets therein for communicating said ports connect.-

ed to Aopposite ends of said working chamberwith said inlet and exhaust ports, respectively, said pockets and ports being so positioned that when said piston valve is in its lowermost position pressure iluid is applied to said working chamber to move said reciprocable cylinder upwardly, and when said valve is vin its uppermost position uid is applied to said working chamberto move said reciprocable cylinder assembly downwardly, an auxiliary valve rod extending vertically through said valve chest and through said annular piston valve and sealing therewith, motion reversing mechanism coupling said auxiliary valve to said cylinder assembly whereby-movement of said cylinder upwardly Vshifts said auxiliary valve downwardly and'downward movement of said cylinder assembly shifts said auxiliary valve upwardly, said auxiliary valve having passages therein terminating in ports communicating the lower end of said piston valve with said inlet port and the upper end of said piston valve with said exhaust port when the auxiliary valve is in up position, and for communicating theupper end of said valve chest with said inlet port andthe lower end of said valve chest with one ofsaid exhaust ports when said auxiliary valve is in down position, a pump unit, and means for actuating said pump unit in response to reciproeation of said cylinder assembly.

7. In a fluid-actuated well pump, having iluid` connection with the surface through an outer tubing for the discharge of exhaust fluid and pumped iiuid and separate fluid connection with the surface through a smaller inner tubing positioned within the outer tubing for the `receptionrof operating liiuidvunder high pressure, a`

motor unit adapted to be submerged'in exhaust and pumped iiuid within said outer tubing and positioned below the lower end of the inner tubing and having iluid connection therewith, said unit comprising a stationary plunger member, means for supporting the lower end of said plunger member from said outer tubing, said unit also comprising a traveling cylinder assembly .reciprocable with respect to said stationary lowered'into a well through an outer tubing string while supported on an inner tubing string, and having fluid connection with both the inner and outer tubing strings when positioned in said well a stationary motor plunger member having a1 supporting base on its Alower end, a cooperating seat on said outer tubing for engaging said base and vsupporting said plunger member when the latter has been lowered into working position within said outer tubing, telescoping sleeve means on the upper end of said stationary plunger member for communicating said plunger member with said inner tubingand supporting the plunger member from the inner tubing while permitting a substantial amount of relative movement therebetween, an .expansible skirt member on the lower end oi.' said inner tubing, a skirt-expanding cone on the upper end of said plunger member and shoulder means in said outer tubing so spaced above said seat that when said plunger base reaches said seat further downward movement of said inner tubing forces said expansible skirt down over said cone and expands the skirt to engage with and rest upon said shoulder,

whereby the weight of said inner tubing is sup- Vmotor barrel `surrounding said plunger member and cooperating therewith to-dene a working chamber, andvalve means and fluid passages in said plunger member for supplying pressure uid to said working chamber from said innertubing and exhausting fluid from said working chamber to said outer tubing. n

9. A device as described in claim 8 in which said telescoping sleeve means comprises a sleeve depending from and ,in communication with said inner. tubing, said sleeve extending down into a recess provided therefor in the upper end of said plunger member, packing means on said plunger member sealing with said sleeve and constituting withI said sleeve a `fluid-tight closure for said recess, a shoulder on said sleeve below vsaid packing means for engaging therewith and limiting upward movement of said sleeve with respect to said plunger member, said sleevehaving perforations therein below said shoulder for the passage of pressure iluid into said plunger recess and longitudinal passages in said plunger member communicating said recess with said valve means. i

10. In a :duid-actuated well pump adapted to be lowered into a well through an outer tubing string while supported on an inner tubing string, and having fluid connection with both theinner and outer tubing. strings when positioned in said well, a stationary motor plunger member having a supporting base adapted to seat on a cooperating seat on the outer tubing and be supported thereby when the pump has been lowered into working position within said outer tubing, a sleeve depending from and in communication with said inner tubing, said sleeve extending down into a recess provided therefor in the upper end of said plunger member, packing means on said plunger member sealing with said sleeve, a shoulder on saidsleeve below said packing means for engaging therewith and limiting upward movement of said sleeve with respect to said plunger member` and terminatingA in an orice inl the bottom of said recess, a rod having a plug on the lower end thereof for closing said orice,

said rod extending up into said sleeve, a bushing `in the lower end of said sleeve for guiding said rod and sealing the lower end of said sleeve, andV shoulder means on the upper end of said rod for engagement by said bushing when said plunger member is supported by said inner tubing to lift said plug from said orice and thereby establish direct fluid communication between said inner and outer tubings.

11. In a huid-actuated well pump adapted to be positioned within and supported by an outer tubing extending to the surface and in which the pump seals olf the outer tubing, whereby oil may be inducted from the well into the pump through the lower portion of the outer tubing and pumped oil and exhaust fluid discharged from the pump may be transmitted to the surface through that portion of the outer tubing extending thereabove, and in which the pump includes a fluid-actuated driving motor supplied with pressure fluid through an inner tubing which also functions as a supporting vstring to klower and withdraw the pump through the outer tubing; a pump body incorporating a reciprocating pump and motor mechanism and comprising a base member adapted to seat on and seal with'a pump supporting seat in said outer tubing, said mechanism including a rod reciprocable in said pump body, latch means in said base member movable into engagement with said rod when the latter is in a predetermined position for preventing movement oi said rod from said position, spring actuating means for moving said latch meansl into engagement with said rod, and means rendered operative in response-to seating of said base member in said seat in the outer tubingA for releasing said latch means from engagement with said rod.

i2. in a fluid-actuated well pump adapted to be positioned within'and supported by an outer tubing extendingto the surface and in which the pump seals on the outer tubing, whereby oil may be inducted from the well into the pump through the lower portion of the outer tubing and pumped oil and exhaust uid discharged from the pump may be transmitted to the surface through that portion of the outer tubing extending thereabcve.

and in which the pump inciudes a fluid-actuated driving motor through an inner tubing which also functions as a supporting string to lower and withdraw ie pump through the outer tubing; a pump body incorporating a reciprocating pump and motor mechanism having a base member adapted to seat on and seal with a pump supporting seat in said outer tubing, said base member comprising a sleeve slidably mounted on said pump body ior limited vertical movement with respect thereto, spring means for normally maintaining said sleeve in lowermost position on said pump body while permitting upward movement thereof in response to seating of the pump, said suppiied with pressure fluid mechanism including a rod reciprocable in said pump body, a detentin said pump body movable into and out of engagement with said rod, and means on said sleeve for forcing said detent into engagement with the rod when the sleeve is in lowermost position and releasing the detent when the sleeveis in uppermost position.

13. A device as described in claim 11, in which said latch means comprises a plunger. reciprocable in a passage in said base, member, one end of which passage is ported above the seating surface of said base member and the other end of which is ported below said seating surface, a detent movable into and out of engagement with said rod, means on said plunger cooperating with said detent to maintain the latter in engagement with said rod when the plungerv is in one end positionand release the detent from engagement with the rod' when the plunger is in the other end position, spring means for normally urging said plunger in said one end position but yielding in response to dilerential pressure applied to the opposite ends of said passage to permit movement of saidplunger into said other end position, whereby said mechanism may be maintained locked in a predetermined position during lowering of said pump in said well and released following seating of the pump in the outer tubing by establishing a column of liquid in said outer tubing above said pump.

ifi. In a fluid-actuated well pump adapted to be positioned in a well and having exhaust fluid connection with the surface through an outer tubing string, and pressure fluid connection with' the surface through an inner tubing string positioned within the outer tubing, a motor unit cornprising a stationary plunger assembly having a base member thereon adapted to seat on a supporting ange provided therefor in the outer tubing string, a cooperating reciprocable cylinder assembly comprising a cylinder of substantial length surrounding the major portion of said plunger assembly and defining therewith'a Working chamber adjacent the central portion of said cylinder, said cylinder projecting substantially above and below said working chamber and defining with said plunger annular passages above and below said working chamber, valve means within said stationary plunger, means connecting said stationary plunger to the lower end of said inner tubing, a passage in said plunger communicating said inner tubing with said valve, passages in said valve communicating said valve with said working chamber, exhaust passages extending iroin said valve to said annular passages defined by said cylinder and plunger assemblies above. and below said working chamber, a pump positioned below said motor unit and connected thereto and adapted to discharge pumped fluid up through said outer tubing past said mot-or cylinder, whereby exhaust oil from said Valve discharged into said outer tubing through the annular passages defined between the ends of said cylinder above and below said working chamber displaces any pumped fluid tending to approach the cooperating slidingpcontact surfaces of said motor mechanism. 2

15. in a fluid-actuated pump, an inner member having a cylindrical outer surface, an outer member reciprocable with respect to said inner member and having a cylindrical inner surface spaced from and surrounding said outer surface on said inner member, and constituting therewith the inner and outer walls of an annular working chamber, a pair of spaced apart flanges Ving chamber by passages in said inner member for controlling the ow of fluid to and from said working chamber, means for supplying pressure fluid to and exhausting uid from said valve, and means for actuating said valve in response to predetermined relative movements of said inner and outer members.

GRANVIILE S. KNOX.

Images