US2994279A - Subsurface hydraulic well pump - Google Patents

Description

Aug, l, 1961 H. E. McGowEN, JR 2,994,279

SUBSURFACE HYDRAULIC WELL PUMP H. E. MCGOWEN,Jr

INVENTOR.

BY g

Arrowfy Aug. 1961 Filed April 13, 1959 H. E. MCGOWEN, JR

SUBSURFACE HYDRAULIC WELL PUMP 3 Sheets-Sheet 2 Aug. 1, 1961 H. E. MCGO'WEN, JR 2,994,279

SUBSURFACE HYDRAULIC WELL PUMP Filed April 13, 1959 3 Sheets-Sheet 5 ATTORNEY United States Patent 2,994,279 SUBSURFACE RAULIC WELL PUMP Harold E. McGowen, Jr., Houston, Tex., assignor to gamen, Incorporated, Houston, Tex., a corporation of exas Filed Apr. 13, 1959, Ser. No. 805,982 3 Claims. (Cl. 10S-4179) This invention relates to an improved double acting pump unit of the type to be retrievably positioned near the lower end of a well tubing string through which operating liquid under pressure is delivered to a hydraulic motor section of the unit assembly and whose response imparts relative reciprocation to a piston and cylinder active on the well iluid to lift the same from the well.

An object of the invention is to provide an improved unit comprised of readily assembled components simpliiied in structure and capable of economic manufacture and designed for ease of installation and removal and for long life without maintenance attention.

A further object of the invention is to provide a double acting reciprocatory pump having balanced power fluid requirements and equal deliveries on both strokes with large induction and eduction flow areas providing undivided liquid paths, each for passing the whole of the liquid stream as a single column and containing a minimum number of check valves, each controlling fairly unrestricted valve porting and without exceptionally long and devious passages resistant to free ilow.

Another object of the invention is to provide a reciprocatory piston plunger and cylinder assembly whose slide bearings and pressure chambers are sealed by self iitting ilexible rings which act to minimize fluid leakage even after long periods of wear and abrasion.

A preferred but not necessarily the only embodiment of the invention is illustrated in the accompanying drawings wherein FIGS. l and 2 illustrate in Vertical cross section and somewhat schematically a pump unit according to the invention with the parts in FIG. 1 positioned as during a plunger upstroke and the same parts in FIG. 2 positioned as in a plunger downstroke; FIGS. 3A, 3B and 3C are vertical sectional views, companion to one another, of a fragmentary portion of the pump unit with the mechanical parts formed and intertted for commercial production purposes; and FIG. 4 is a transverse section as one line 4 4 of FIG 3C.

The length of a reciprocatory pump stroke can vary between a few inches and a great many inches and for practical purposes a stroke of about twelve inches would ordinarily be accepted. For a twelve-inch pump stroke, the proportions of .the parts in FIGS. SA-B-C will be appropriate for a unit which is about thirteen feet long and is to be received within a tubing string whose internal diameter is about two inches. For convenience of disclosure, the proportions of the parts shown in FIGS. 1 and 2 are somewhat reduced axially and may be considered as representative of a very short stroke pump.

Referring particularly to FIGS. 1 and 2, the tubing section 1 is illustrative of a lower end portion of a long string extended from ground surface and through a well bore to a fluid producing formation in the earth. At its lower end, it receives a retrievable and sealed-ott housing 2 for a ball valve 3 constituting the usual standing valve. Immediately above the standing valve there is located the engine and pump unit which has its lower barrel end 4 iitted to and sealed within the upwardly open socket of the standing valve housing 2 and has its upper end seated and sealed as at 5 on the tubing string 1 so as to be centered within and to provide an annular passage 6 between the tubing string and the pumping unit. Between the sealed upper and lower ends of the ICC pair of concentrically nested inner and outer tubular members 9 and 1d, of which the inner hollow member 9 constitutes a reciprocatory plunger and the outer hollow member 10 constitutes a housing or pump barrel to enclose the operating parts and to be xedly mounted in operating position. At its upper end the outer housing tube 1t? terminates in a hollow iishing neck 11 for releasab-le attachment with and manipulation by a suspension wire line tool if desired'. Normal installation and removal will be by pumping the unit assembly down or up in the tubing string. Immediately below the fishing neck 11 the housing body carries a :busto-conical swab or sealing flap 12 which peripherally bears outwardly on the tubing string and wipes slidably thereon during upward removal travel of the unit under force of liquid pumped down the conduit 8 and active below the swab 12. Installation is by descent of the unit to workin-g position in which the unit is held by the upstanding liquid column pressure.

Immediately below the upper iishing neck 11, the internal bore of the housing 10 is enlarged for a portion of its length and affords a cylinder 13 in which is slidably tted a piston or radially enlarged hollow formation 14 on the upper end of the plunger 9. The bottom of the cylinder 13 is defined by an internal housing partition 15 which is also an annular bearing guide for the slide plunger 9 and carries suitable packing seals 16 slidably engaged with the periphery of the plunger. Similar annular bearing guides 17 and 1S having packing seals 19 and Ztl engage the plunger and are carried by the housingk in axially spaced apart relation one to another and partition the intervening space. Between the endmost bearing 15 and the intermediate bearing 17 there is formed by the clearance space within the housing and around the plunger, an outlet chamber 21 whose minimum axial length will be at least as great as the pump stroke. One orl more ports 22 communicate the interior of the hollow plunger with the chamber 21 and these ports are located so as to be open at all times throughout the range of pump stroke. Additional large size ports 23 are formed in the Wall of the housing lil for communicating the discharge chamber 21 with the annular outlet passage 6 between the housing and the tubing string 1.

The annular space within the housing [1d between the intermediate spacer 17 and the lower end spacer 18 cooperates with a peripheral spacer enlargement or piston formation 24 on the plunger and the piston has peripheral guide bearing on the interior of the housing and carries suitable slide packing 25; There is thus formed on opposite sides of the piston or spacer 24 a pair of variable volume chambers 26 and 27 and which alternately draw in and expel well liquids during plunger reciprocation.

Intake and exhaust passages Serving both pump charnbers are formed by the hollow pump plunger which, in the region of the piston 24, has an internal partition 23` in the form of a substantially Z-shape closure wall providing side by side continuations of the intake passage 29 below the partition and of the outlet passage 30 above the partition. At its upper end, the extension of the passage 29 opens outwardly through a port 31 in the plunger wall and leads into the upper pump chamber 26. The downward extension of the outlet passage 30 leads from a port 32 in the wall of the plunger for outow from the lower pump chamber 27. These side ports and passages `are of large size to receive the full amount of the liquid stream without restrictive divisions thereof and each is controlled by a single check valve. That is, the passage extension leading from the outflow port 32 terminates in a large ported seat for a ball check valve 33 and a similar check valve 34 seats over a large port and prevents backtlow from the passage extension leading to the port 31. Below the check valve 34 and laterally offset to one side of the intake passage 29, is a chest or cage 35 through which the passage communicates to a side wall port 36 leading into the lower pump chamber 27. A check valve 37 is enclosed within the cage 35 and seats over a relatively large port to prevent backow from the lower chamber 27. The alternately open inlet ports 36 and 31 to the two pump chambers are thus in parallel flow relation within the intake passage 29 in the bottom of the plunger and they are in axially spaced relation on opposite sides of the piston 24. The eccentric or axially offset mounting of the cage 35 provides clearance therearound within the passageway leading to the uppermost inlet port 31 and the ow clearance space in the passageway around the oiset cage approximates the flow area through the cage.

Similarly, there is a laterally oiset valve cage 38 in the outlet passage Sil containing a ball check valve 39` and controlling aside wall outlet port 40 leading from the upper pump chamber 26 and in parallel flow relation with the outlet port 32 from the lower pump chamber 27. Again the laterally oiset disposition of the cage 38 provides equal area flow paths through and around the cage from the respective and alternately open pump chambers to the upper outlet chamber 21.

Reference has been made to the drive motor for reciprocating the plunger and which responds to pressure fluid introduced at the top of the well string 1 for flow into the motor. Such pressure liquid acts on one side or the other of the head of the cup-shaped piston 14 as controlled by a reversing valve 42 whose movement from one position to another is motivated by or is under influence of tubing string pressure uid and is controlled by piston travel position within the motor cylinder `13. For upward movement of the plunger assembly, the parts are in the relative positions shown in FIG. l, wherein pressure drive fluid is valved through a port 41 inthe plunger wall for flow into the piston cylinder below the piston 14 and upward action on the underside of the piston. At such time, the opposite end of the piston cylinder above the piston 14 is vented through a port 42 to the annular outflow passage 6 between the tubing string 1 and the housing 10. -A down stroke occurs when the parts are in the FIG. 2 position whereby the piston cylinder port 41 as controlled by the reversing valve vents the cylinder 13 below the piston 14 and pressure fluid above the skirted piston head forces the plunger downwardly. The control valve head 42 alternately seats downwardly, as shown in FIG. l, to block the upper end of the pressure relief passage 30 and seats upwardly, as seen in FIG. 2, to block a pressure fluid passage through the piston head.

For controlling valve action, it is connected by an upwardly extending stem to a skirted slide piston 43 whose skirt peripherally bears on the inside of the motor piston 14 `and has sliding and sealing bearing engagement interiorly with the outside of a dependent tail pipe or tube 44 projected into the top of the cylinder 13 and forming a continuation of the fluid pressure delivery passage. The relative lengths of the interiitting skirt of the valve controlling piston 43 and of the dependent tail pipe 44 are such that as the motor piston 14 approaches the end of its down stroke the top of the valve skirt 43 will move below the lower terminal of the tail pipe 44 and be exposed to drive pressure fluid for an unbalance of opposing surface areas whereby the valve head 42 Will be shifted downwardly for directing pressure fluid into the previously vented piston cylinder 13 below the head of the motor piston 14. Upward plunger travel will then occur and bring the skirt of the piston 43 back into overlapping relation with the tail pipe 44, trapping some of the pressure fluid above the skirt upper end and an inwardly extending annular flange 45 at the free end of the skirt of the motor piston 14. Throughout the lower portion of the range of movement, this internal flange 45 will have sealed sliding engagement with the tail pipe 44 but as the drive piston approaches its upper travel limit, this llange 45 will come into alignment with an inwardly relieved region 46 on the tail pipe periphery for the exhaust of trapped liquid in the pocket above the upper end of the skirt of the valve positioning piston 43. The resulting unbalance of opposing surface areas exposed to the pressure uid results in raising the valve 42 to its upper seat, as shown in FIG. 2. Automatic actuation of the reversing valve repeats itself at the end of each stroke and the mechanism responds to the pressure of fluid delivered through the tubing string 1 for the maintenance of the desired lifting operation throughout both strokes.

Throughout the range of upward travel of the plunger, the pump chamber 27 expands in volume and draws in well fluid past the check valve 37 and the pum-p chamber 26 contracts in volume to displace liquid content therefrom outwardly through the check valve 39. Pressure differentials seal the check valves 33 and 34 against back flow of fluid therearound. On the other hand, a down stroke of the plunger increases the space within chamber 26 and pressure differentials will close the check valve 39 and open the check valve 34 for the inflow of well fluid to ill the pump chamber 26. Because the volume of the chamber 27 is now decreasing, the fluid therein causes the check valve 37 to close and is displaced upwardly past the open valve 33 through the outflow passage in the plunger.

It will be noted particularly that the passages to and from both chambers are formed entirely within the hollow plunger and that these passages are of relatively large area without multiple streams in either the induction or eduction equal volume flow paths to and from the respective pumping chambers. Each path for each chamber contains but a single check valve for co-operation with a relatively large port through the co-operating valve seat. Accordingly, frictional resistance to ilow and the likelihood of clogging obstruct-ions as occur with multiple and smaller porting, are reduced to a negligible degree.

Additionally, the passages interiorly of the hollow plunger, both above and below the division partition 28, are provided with special valve cages for the check valves 37 and 39 respectively which, to insure a single stream unrestricted flow path past the same, are disposed ecce-ntrically within the passages or are laterally offset from the axis of the plunger. The dimensions of the cages in relation to the surrounding hollow plunger spaces are controlled so that the flow paths around the valve cages are each a single unobstructed clearance for the full ilow and of an area which substantially corresponds to that with the flow passage through the valve cage. The single passageways to and from each pumping chamber are designed to handle equal volumes of fluid so that there is no starving of 4any pump space nor pressure build-up in some regions materially inexcess of pressures elsewhere. Well formation pressures ldo not oppose but may assist pump lift action.

For manufacturing purposes, lboth the plunger 9 and the housing 10 are assembled from a. num-ber of separately formed components, usually arranged in end to end relation, as more particularly seen in FIGS. 3A-4. Thus in FIG. 4 there is shown the laterally offset relationship of the valve cage 35 to the hollow plunger and the induction passage 29. This cage 35 is a simple cup-shaped unit having a side wall opening aligned with a similar opening in the wall of the plunger 9 and welded thereto in off-center position. The seat for the ball check 37 is a renewable ring 47 held within the cup interior by a threaded screw 48. The oiset cage 38, as seen in FIG. 3A, consists of a cup 49 containing the ball check 39 and a seating ring Si) for the ball. The cup 49 is threaded on an elbow 51 having a side port for al-ignment with a co-operating port in the plunger wall and being welded to the wall so as to leave passage clearance throughout the major portion of its circumference.

The pump piston 24, as in FIG. 3B, is preferably formed with a large number of peripheral grooves to receive expansible spring metal split rings 52 for a wiping seal fit with the interior of the piston cylinder wall of the housing 10. Each of the several plunger guiding spacers or partitions 15, 17 and 18 involves a coupler tube 53, as in FIG. 3A, having opposite ends threaded interiorly of two adjoining housing sections and formed with an internal pocket closed at its lower end by an inwardly projected annular ring 54 having a plunger wiper ring 55 and closed at its upper end `by a gland nut 56, also having a wiper ring 57. Pocketed within the tube 53 is a stack of solid collars 58, each of which has an enlarged or counterbored upper end to receive one or more contractile spring metal rings 59 which haveslide sealing t with the exterior of the reciprocatory plunger 9. Each contractile sealing ring is annularly split so that its ends can move together or spread apart to accommodate spring action of the sealing ring.

What is claimed is:

1. In a double acting pump, a cylinder having opposite end closure walls, an elongated plunger extended through the cylinder and comprised of an intermediate hollow piston slidably engaged with the cylinder and a pair of reduced diameter hollow tubes projected upwardly and downwardly respectively from the piston and slidable in said end closure walls to provide upper and lower variable voliune pumping chambers within the cylinder, a longitudinal partition of greater length than the piston and extended through and beyond both ends of the hollow piston and between the tube walls in regions thereof respectively above and below the piston, said partition closing oi communication between said tubes and providing a pair of side by side separate passages on opposite sides of the partition, one passage communicating with the upwardly projected tube as a downward extension thereof and the other passage communicating with the downwardly projected tube as an upward extension thereof, the wall of the upwardly projected tube having a pair of longitudinally spaced apart lateral ports therethrough, one of such ports being located below the top of the partition and above the piston and constituting an inlet into the upper chamber from the passage extension of the downwardly projected tube and the other of such ports being located above the partition and constituting an outlet from the upper chamber and into the upwardly projected tube, the wall of the downwardly projected tube also having a pair of longitudinally spaced apart lateral ports therethrough, one of which yis located above the bottom of said partition and below said piston and constitutes an outlet from the lower chamber into the passage extension of the upwardly projected tube and the other of which is located below said partition and constitutes an inlet from the downwardly projected tube and into the lower chamber, check valves controlling the several tube wall ports, cages for the valves at the outlet port from the upper chamber and at the inlet port to the lower chamber and being located interiorly and offset laterally within the downwardly and upwardly projected tubes respectively and subdividing the interior of each hollow tube into parallel branch passages leading respectively through the interior and about the exterior of the lateral'- ly offset valve cage.

2. An elongated plunger assembly for a double acting pump, including a hollow piston having a peripheral bearing portion land top and -bottom wall extensions of reduced diameter projecting beyond opposite ends of the bearing portion and each terminating in a coupling formation and having a side wall port in the region between the coupling formation and the bearing portion, a longitudinal partition within the hollow piston closing o from one another the side wall ports in said top and bottom wall extensions and defining a pair of passages on opposite sides of the partition, one connecting the interior of the bottom extension with the side wall port in the top extension and the other connecting the side wall port in the bottom extension with the interior of the top extension, a lower Ihollow rod assembly having its upper end coupled to said bottom wall extension and having a lateral port in the rod wall below said upper end, a check valve housed within the rod assembly and above said lateral port, a valve cage in communication interiorly thereof with said lateral port and secured internally within and in lateral offset clearance relation to said lower hollow rod assembly, an `upper hollow rod assembly having its lower end coupled to said top wall extension and having a lateral port in the rod wall above said lower end, a check valve housed within the upper hollow rod assembly and below the last mentioned lateral port, a valve cage communicating with said last mentioned lateral port and being secured internally within and in lateral clearance relation to said upper hollow rod assembly and a check valve in each cage.

3. In a double acting pump, a cylinder, closure members at opposite ends of the cylinder, a hollow piston having an intermediate large diameter portion in slide bearing engagement with the cylinder and reduced diameter tubular extensions projected axially from opposite ends of the intermediate large diameter portion, a first hollow rod connected to and projected from one of said tubular extensions and through one of the cylinder end closure members as an exhaust passage and said rod cooperating with the piston and cylinder in forming a rst pumping chamber, a second hollow rod connected to and projected from the otther tubular extension and through the other cylinder end closure member -as an inlet passage and said second hollow rod co-operating with the piston and cylinder in forming a second pumping chamber, an internal partition extending longitudinally within said hollow piston and forming longitudinal passages on opposite sides of and closed from one another -by said partition, one in axial continuation of said exhaust passage and the other in axial continuation of said inlet passage, s-ide -wall port means in the aforementioned one of said tubular extensions and in the second hollow rod communicating the inlet passage with the rst and second pumping chambers, side wall port means in said other tubular extension and in the first hollow rod communicating the iirst and second pumping chambers with said exhaust passage and means controlling ow through the side wall port means respectively and comprising check valves contained solely within the rst and second hollow rods.

References Cited in the file of this patent UNITED STATES PATENTS 202,633 Clute Apr. 23, 1878 284,859 Johnson Sept. 11, 1883 358,570 Putnam Mar. l, 1887 2,537,410 Howard Jan. 9, 1951 2,727,467 Russell Dec. 20, 1955

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