US2489505A

US2489505A - Deep well pump

Info

Publication number: US2489505A
Application number: US565470A
Authority: US
Inventors: Benjamin F Schmidt
Original assignee: Individual
Current assignee: Individual
Priority date: 1944-11-28
Filing date: 1944-11-28
Publication date: 1949-11-29
Anticipated expiration: 1966-11-29

Description

Nov. 29, 1949 B. F. SCHMIDT 2,489,505

DEEP WELL PUMP Filed Nov. 28, 1944 4 sheets-sheet 1 j] ATTORNEY.

B. F. SCHMIDT DEEP WELL PUMP Nov. 29, 1949 4 Sheets-Sheet 2 Filed Nov. 28, 1944 TTORNEY.

.INVENTOR 7 a /v f/ j M I 1 m M A@ j B. F. s'cHMxD-r Nov. 29, 1949 DEEP WELL PUMP 4 Sheets-Sheet 3 Filed Nov. 28, 1944 INVENTOR. CHM/D 5. w A M/W m' ORNEY.

Nov. 29, 1949 B. F. scHMlD'r 2,489,505

DEEP WELL PUMP Filed Nov. 28, 1944 4 Sheets-Sheet 4 la? J2 u I0] 1 l @t 107 v 15 103 119 1 Z4 10.6% M. J 10 106 125 f3] f 122 Y f V f2 Z2 N 125 9 150 EL?? i Jn 124 120 ,24 112 ff@ 1./7 jj 121 2 112 120 Qttt M ML @9.12

INVENTOR. EM/AMW 5CH/WD7;

BY f ff/572;

AT RNEY.

Patented Nov. 29, 1949 i n 4UNITED STATES PATENT OFFICE :,mas

l naar WELL PUMP Benjamin F. schmidt, Los Angeles, oeuf.

Appleman November zs, 1944, serial No. 565,410

s emma. (ci 1oz-4s) My invention relates to submersible pumps and has particular reference to an insert pump which is particularly adapted to the pumping of deep wells such as oil wells and the like.

In the oil producing art. it is common practice to use reciprocating pumps to pump oil to the ground surface from oil wells of great depth. These pumps are mounted deep within the well bore upon the lower end of a string of flow tubing through which the pumped oil is conveyed to the ground surface. Conventionally, a cylinder or barrel is attached, within which a piston or plunger is reciprocated by means of power transmitted from the ground surface through a string of reciprocating sucker rods.

This type of pumping equipment is inemcient and only a small fraction of the total energy put into the system is useful in lifting oil to the ground surface. In my copending application. Serial No. 548,518, filed August 8, 1944, now Patent No. 2,455,022 and entitled "Submersible double-acting uid piston deep well pump," I have disclosed an electric motor driven fluid piston reciprocating insert pump which has been designed particularly to increase the overall eflciency of deep well pumps. The present invention is directed to a novel type of pumping unit which is particularly adapted for use in an assembly of the character` disclosed `in the aforementioned copending application.

It has for an object, the provision of a novel form of pulsator unit which is used to convert the rotating energy of the electric motor into reciprocating fluid energy for operating a fluid piston reciprocating pump.

It is an additional object of my invention to provide a novel form of pumping unit which may be used in place of the uid piston reciprocating pump and which employs a series of pressure expansible elements such as bellows housed within a casing and which operate in conjunction with the usual inlet and outlet valves to raise the crude oil from the well bore to the ground surface.

It is an additional object of my invention to provide in a deep well pump of the character described hereinbefore a multi-unit diaphragm pumping assembly in which the expansion and contraction of the ilexible diaphragms are employed to raise the crude oil to the ground surface.

It is a still further object of my invention to provide novel features of construction and a simple unitary assembly permitting various parts of the structure to be removed as a unit from vfollowing specifications, read in connection with the accompanying drawings, wherein:

Fig. 1 is a side elevational view illustrating the general form and appearance of the preferred embodiment of my invention;

Fig. 2 is a longitudinal sectional view through the lower part of Fig. 1 and showing the details of construction of the pulsator element;

Fig.v 3 is a cross sectional view taken substantially along the line III-III of Fig. 2;

Fig. 4 is a cross sectional 'view taken substantially along the line IV-IV of Fig. 2;

Fig. 5 is a longitudinal sectional view illustrating the details of construction of one form of pumping element, the form illustrated comprising a fluid piston reciprocating pump;

Fig. 6 is a cross sectional view taken substantially along the line VI-VI of Fig. 5;

Fig. 7 is a cross sectional view taken substantially along the line VII-VII of Fig. 6;

Fig. 8 is a longitudinal sectional view similar to Fig. 5 but illustrating a modified form of pumping unit which employs pressure expansible elements for pumping the crude oil;

Fig. 9 is also a longitudinal sectional view simliar to Fig. 5 but illustrating another modication of the invention employing a flexible diaphragm as a pumping element;

Fig. 10 is a cross sectional view taken substantially along the line X-X of Fig. 9;

Fig. 11 is a longitudinal sectional view illustrating a modified form of pulsator element which may be used in place of that illustrated in Fig. 2;

Fig. 12 is a cross sectional view taken substantially along the line XII-XII of Fig. 11; and

Fig. 13 is a cross sectional view taken substantially along the line XIII- XIII of Fig. 11.

Referring to the drawings, I have illustrated the preferred embodiment of my invention in Fig. 1 as comprising a pump housing I which is attached to the lower end of a string of ow tubing 2 as by means of a divided member 3 which provides for the introduction into the housing I of an armored electrical cable 4. The cable l is carried to the ground surface alongside of the flow tubing 2 and may be secured thereto at suitable intervals as by means of clamps or straps 5.

The electric cable 4 terminates in a junction box represented by the dotted rectangle 6 from which electrical connections extend to an elecandasse tric motor driven unit 7 represented by the dotted' line rectangle bearing that reference character. I The rotating shaft of the electric motor 'l is coupled to a reduction gear unit represented by the dotted rectangle 3 in Fig. l. A slow speed power take-off shaft of the reduction gear is'applied to the power input shaft of a pulsator unit represented by the dotted rectangle Si, by means oi V which the rotary power produced by the electric motor 8 is converted into a reciprocating fluid power which is used to operate a pumping as= sembly represented by the dotted rectangle i@ in Fig. l and which operates to lift crude oil ad mitted to the assembly through the inlet it to the ground surface through the member i3 and ow tubing 2.

By preference, the junction box d, electric motor l and gear reduction e are constructed in accordu ance with the teachings contained in my aforementioned copending application. The present invention is directed particularly to the construction of the pulsator unit 9 and the secondary pumping unit I0.

Referring to Fig. 2, I have illustrated therein the pulsator unit 9 as being mounted within an interior housing I2. The housing I2 is preferably mounted concentrically within the outer housing I and held spaced therefrom by any suitablemeans so as to define between the housings I and I2 an annular space i3 through which crude oil is conveyed to the ow tubing 2. The inner housing I2 supports an upper pump body I4 which is disposed between an upper bearing member I5 and a lower bearing member I6. A

central pump body il is positioned between the bearing member I5 and another bearing member I8.

Between the bearing member I8 and a bottom bearing member I9 there is positioned a lower pump assembly 20. The three assemblies and the four bearing members are secured to each other and to a lower closure 2I by means of a plurality of bolts or studs 22 passing longitudinally completely through the assembly. The lower closure 2| is secured to the inner housing I2 as by means of threads 23.

Each of the pump bodies I4 are identical and` are longitudinally bored as indicated at 24 to receive a single crank shaft 25 which is journaled in each of the bearing members I5, IB, I8 and I9 as by means of ball bearings or other suitable anti-friction bearings 26. The upper end of the crank shaft 25 is suitably connected as by means of a coupling 2'I to the slow speed power takeoi shaft of the gear reduction unit 8. Each of the pump bodies I4 are provided with three laterally extending cylinder bores 28, 29 and 30, these bores being spaced circumferentially 120 and being spaced vertically a distance slightly exceeding their diameters.

Within each of the cylinder bores there is reciprocally mounted a piston 3l which is coupled by means of a wrist pin 32 to a connecting rod 33. Each of the three connecting rods 33 are rotatably mounted upon a single crank throw 34 as by means of needle or roller bearings 35 formed upon a split bushing as indicated in Fig. 3. The upper cylinder bores 28 of each of the pumping bodies I4, I'I and 20 are interconnected by longitudinally extending uid passages 36. Corresponding passages 36 in each of the pump bodies are interconnected by means of apertures 3`I provided in the intermediate bearing members I 6 and Il. In a similar manner, the center cylinder borezs'of each or the punp bodies u, n and 2a I are interconnected by means of a longitudinally extending fiuid passage 3S and a similar set of iiuid passages 40 `are used to interconnect the lower cylinder' bores 30 of each of the pump bodies lli, il and It will be seen that the assembly just described constitutes a multi-piston pump in which three groups of three cylinders each are mounted at with respect to the others. Each of the groups of three comprises one in each of the pump bodies i6, il and 20 and the pistons of each group are simultaneously operated. With this construction the crank throw 34 may be made the same for each of the three pump bodies as is clearly shown in. Fig. 2. Journaling o the crank shaft 25 at the bearing members it and it is accomplished by forming an enlarged shaft portion di which is provided with a circular cross section disposed concentrically with respect to the axis of rotation of the shaft 25 and which is received within the inner race of a ball bearing 42.

The construction of each of the pump bodies I4, Il and 2U may be simplied by formingi each of the bodies from three identical sector-shaped parts ida, Mb and I4c as shown in Fig. 3. It will be noted that three of the attaching bolts 22 are used so that one of each of the bolts passes through each of the sections' I4a, I4b and I4c. Radial abutting faces I4d serve to hold the parts against circumferential movement relative to each other and a close t between their exterior surface and the interior of the inner barrel I2 holds the' parts against radial outward movement. Radial inward movement is prevented by the interaction of the abutting faces I4d.

As the crank shaft 25 is rotated, an operating fluid contained within the passages 36, 39 and 40 and in the cylinder bores connected thereto is reciprocated as the pistons are advanced and retracted within their respective cylinder bores. The reciprocation of the fluid thus eli'ected is used to operate the pumping unit I which in turn operates to lift the crude oil to the ground surface.

I have shown in Fig. 5 as one form of pumping unit which may be used a iiuid piston reciprocating pump. lThe unit shown therein comprises a pump body 43 which is centrally bored as shown' at 44 to receive crude oil admitted through an inlet opening 45 past a bali check valve 46 mounted within a lower support 41 and resting upon a valve seat 48. symmetrically disposed about the central bore 44 there are provided three pairs of longitudinally extending bores identified in Fig. 7 by the reference characters #19a-49h, 50ablib and 5Ia-5Ib. These six bores comprise a three cylinder fluid piston reciprocating pump and each pair is respectively associated with the corresponding uidpassages 36, 39 and 4U previously described.

The connection between these passages and the bores 49a, 50a and 5Ia is eiected by means of suitable passages 52, 53 and 54 (Fig. 4) formed in the closure member 2| above described and an upper head member 55 which serves to close the upper ends of the bores 49, 5I] and 5i and which is secured to the lower closure member 2| as by means of bolts 56. The upper head member 55 serves as a housing for three identical inlet valves, one of which is shown at 5`I in Fig. 5. y

It will be noted that the upper head member 55 is provided with three angularly disposed bores 38, each of which receives a valve seat 59 upon which the valve 61 rests. The discharge side of the valve 51 is communicated by a laterally extending passage 60 with an axially extending passage 6| aligned with and communicating with the cylinder bore SIb. A similar intercommunication is eiected between the central bore 44 and the cylinder bores 49h and 60h.

The passages 6I each extend upwardly through the upper closure 55 and receive valve seats 62 upon which are rested outlet valves 63. The discharge side of the outlet valves 63 are communicated by means of laterally extending ports 64 with the annular space Il positioned between the inner housing I2 and the outer housing I.

The lower ends of the cylinder bores 49a and 49h are interconnected by means of a transversely extending channel 65. Similar channels 66 and 61 interconnect the lower ends of the bores Ina-60h and ila-SIb. Within each of the pairs oi cylinder bores 49, 69 and 6I there is placed a quantity of mercury or other suitably heavy fluid Il insoluble in the oil to be pumped sufficient to substantially fill one of the cylinder bores of each pair. Normally each of the bores of a given pair will be filled substantially half full due to the liquid in the interconnected bores seeking equivalent levels. The remaining half of bores 49a, 60a and 6Ia are each filled with operating fluid which is reciprocated by the operation of the pulsator unit 9.

In operation, as the pulsator assembly 9 is operated (the entire fluid system of the assembly 9 being illled with operating iluid) fluid is flrst forced downwardly through one of the longitudinally extending fluid passages, as for example the passage 36. The iluid being communicated with the bores 49a, exerts a downward pressure upon the mercury in that bore and displaces the same downwardly, causing a corresponding rise in the mercury in the associated bore 49h. As the mercury in bore 49h rises, any crude oil which may be contained within the bore 49h above the mercury will be forced upwardly through the passage 6I and past the discharge valve 63 and into the annular space I3, ilow through the passage 56 into the central bore 44 being prevented by the inlet valve 51.

This operation reverses as soon as the pistons of the pulsator 9 have completed their stroke. As

they are withdrawn, the ilow of fluid in the passage 36 is reversed, causing the mercury to rise in the bore 49 and subside in the bore 49h. 'I'he low pressure thus produced above the mercury in the bore 49h raises crude oil through the inlet 45, past the i'oot valve 46 and upwardly through the central bore 44 to be admitted past the inlet valve 51 and into the upper part of the bore 49b through the passages 69 and 6I, reverse flow of iluid from the annular space I3 through the passage 6I being at this time prevented by the closed discharge valve 63.

During the time the cylinder 49m-49h is performing the above described operation, the cylinders 50 and 5I are performing similar operations but are displaced in time phase by an amount equal to 120 of rotation of the crank shaft 25. Each, however, draws crude oil from the central bore 44 and discharges it into the annular space I3. By using the three cylinder arrangement described, a substantially continuous ilow of fluid is maintained within the annular space I3 and avoids the disadvantageous eilects of hydraulic hammer resulting from the lrepeated starting and stopping of fluid ilow so' characteristic of ordinary reciprocating pumps.

Attention is also directed to the fact that the pulsator assembly 9 isin effect a hydraulic trans mission serving to transform the rotating energy of the electric motor into reciprocating fluid energy which is directly used to pump the crude oil. It will be noted that this arrangement eliminates the necessity of using inlet and outlet valves or distributing valves for controlling the fluid pumped by the pump assembly 9.

I have illustrated in Fig. 8 a modiiled form of pumping unit which may be used in place of the assembly shown in Fig. 5. 'Ihe pumping device shown in Fig. 8 comprises three identical pumping units 69, 1I) and 1I mounted one above the other within the housing I. Each of the units comprises a head member 12 which is mounted within the housing I upon an inner housing 13.

The inner housing 13 is spaced from the housing I to dene an annular space 14 through which crude oil is pumped to the ilow tubing 2. Within the inner housing 13 there is mounted a pump barrel 15. The barrel 15 is preferably eccentrically positioned with respect to the housing 14 to denne at one side a relatively wide space within which tubing lines 16 may be placed.

Within the barrel 15 there is placed a pressure expansible element or bellows 11, the interior of which is communicated by means of passages 1I and 19 with the passage 36 of the pulsator assembly 9. The bellows 11 are preferably formed of metal, although other suitably strong resilient material may be used if desired.

i The space within the barrel 15 and the exterior of the bellows 11 is communicated by means of a passage 89 formed in an intermediate head member 12a with a tubing line 8I. The tubing line 9| extends downwardly and into communicationl with an inlet'passage 82 formed in the lower closure 41 and forming a continuation of the inlet passage 45, being connected to the discharge side of the loot valve 46. An inlet valve 83 is interposed in the passage 80 to prevent reverse flow of iiuid therethrough.

The interior of the barrel 15 is also communicated with the annular space 14 by means of passages 84 and 85 within which is interposed a. ball check discharge valve 86.

The unit 10 is similar to the unit 69 just described, except that the interior of the bellows 11 thereof 'is connected by means of a passage I1 formed in the closure 12a to the tubing line 16 which is in turn connected to the iluid passage 99 of the pulsator 9. Likewise an inlet tubing connected to the passage 82 is used to admit crude oil into the interior of the pump barrel forming a part of the unit 10. A similar arrangement is employed with respect to the unit 1I in that tubing lines are used to connect the iluid passage 40 of the pulsator 9 to the interior of the expansible element, whereas the space within the barrel and exterior of the pressure expansible element is suitably connected to the passage 92.

It will be seen that as the pulsator 9 is operated, the pressure expansible elements of each of the units 69, 10 and 1I will be alternately expanded and contracted so as to alternately increase and decrease the free space contained within the barrel 15, the expansion resulting from the pressure developed by the delivery of actuating fluid from the pulsator 9 and the contraction resulting from the sub-atmospheric pressure caused by the withdrawal of iluid from the bellows by the pulsator 9. This changing of the volume within the barrel 15 causes crude oil contained therein to be displaced through tho passages 84 and 85 into the annular space 14 and causes crude oil to be drawn through the passage 82. tubing 8| and the passage 80 into the interior of the barrel. Each of the units operates identically and simultaneously but are spaced apart in time phase an amount equal to 120 of rotation of the crank shaft 25.

I have illustrated in Figs. 9 and 10 another modification of my invention which is similar in many respects to the form of the invention shown in Fig. 8. The principal difference lies in the type of pressure expansible element which is employed. As regards the closure 12, the inner housing 13 and the pump barrels 15, the units shown in Figs. 9 and 10 are identical with those shown in Fig. 8. Likewise, each of the units comprising the assembly shown in Figs. 9 and 10 are similar to each other in the same way that the corresponding units of Fig. 8 were similar.

One of these units is shown in detail in Figs. 9

and 10 as comprising a body member 88 which is provided with a longitudinally extending groove 89. The groove 89 is communicated by means of a series of ports 90 and recesses 9| with a longitudinally extending passage 92 which is in turn directly connected to the passage 36 of the pulsator unit 9. Across the groove or recess 89 there is stretched a diaphragm 93 of flexible material such as synthetic rubber or other oilresistant material. A cover member 94 grooved complementary to the body member 88 is secured to the body member 88 as by means of bolts 95 and serves to secure the diaphragm 93 in place and prevent over-expansion or rupture by limiting movement of the same. The cover member 94 is provided with a plurality of inlet openings 98 which are preferably sloped downwardly as shown in Fig. 9 to reduce to a minimum the possibility of the ports 96 becoming clogged with sand or other foreign material carried in with the crude oil.

As fluid is pumped into and out of the recess 89 through operation of the pulsator unit 9, the flexible diaphragm 93 will be moved from side to side from a first position lying substantially in contact with the surface of the recess formed in the cover 94 to an opposite position lying substantially in contact with the surface of the groove 89. By this means the free volume within the barrel 15 is alternately increased and reduced by an amount equal to the combined vol` urnes of the groove or recess 89 and the corresponding recess formed in the cover member 94.

As the volume is increased, crude oil is admitted vthrough an inlet valve similar to the valve 83 shown in Fig. 8. As the volume is decreased, the fluid displaced thereby is discharged into the annular space 14, past the discharge valve 88 similar to that shown in Fig. 8. Each of the three units of the assembly shown in Fig. 9 operates simultaneously but in time phase relation equal to the 120 spacing of the cylinders in the pulsator unit 9. In so operating, they function to maintain a substantially continuous flow of uid in the annular space 14.

Referring to Fig. 11, I have illustrated therein a modified form of pulsator unit which may be used instead of the unit shown in Fig. 2. As in the form of the invention shown in Fig. 2, the inner housing I2 is mounted concentrically within the outer housing I and is used to support the mechanism comprising the pulsator element. This mechanism includes an upper bearing block |00 within which is journaled as by means of roller bearings |0| a main pump drive shaft |02 8 which is intended to be connected to the slow speed power take-off shaft of the gear reduction unit 8. The shaft |02 carries near its lower end a main drive gear |03 and the shaft |02 terminates in a-stub shaft portion |04 journaled in a bearing block |05 as by means of roller bearings |06.

The main drive gear |03 meshes with three driven gears, one of which is shown at |01 in Fig. 11. The gears |01 are suitably secured to or formed integrally with longitudinally extending drive shafts |08, |09 and ||0 which are spaced equidistant from the axis of rotation of the shaft |02 and circumferentially spaced |20 from each other.

Immediately below the bearing block |05 there is mounted a unitary pump mechanism consisting of a bearing block a cylinder block ||2 and a bearing block ||3. The bearing blocks and ||3 journal as by means of roller bearings ||4 and ||5 a crank shaft ||6. The crank shaft ||6 is provided with a single crank throw ||1 upon which is journaled as by means of connecting rod bushings ||8 and ||9 a pair of connecting rods |20 and |2|. The connecting rods are attached as by means of Awrist pins |22 to pistons |23 which are slidable within transversely extending cylinder bores |24 formed in thecylinder block ||2. The two cylinder bores |24 which are formed in the block ||2 are disposed at an angle of to each other. The upper end of the crank shaft ||6 carries a driven gear |25 which meshes with drive gears |26, |21 and |28 formed, respectively, on the drive shafts |08, |09 and I0.

Two other identical pump units (three in all) are mounted within the inner housing |2 and are arranged to be driven from the drive shafts |08, |09 and ||0 in a manner identical to that just described. Each of 'the three cylinder block assemblies is rotated 120 with respect to the adjacent block so that the six piston and cylinder assemblies comprise three pairs, each displaced 120 from the other two. Like cylinders are connected by means of longitudinally extending passages |30 and these passages are brought through the upper head member 55 to communicate with the cylinder bores 49a, 50a and 5|a previously described.

Attention is directed to the fact that each of the individual units consisting of the bearing blocks and ||3, the cylinder body ||2 and the associated mechanism constitutes a single unit, permitting a main pulsator unit to be made up of as many of these individual units as may be desired, it only being required that the drive shafts |08, |09 and ||0 be made of a length corresponding to the number of units included in the assembly.

It will be noted by reference to Fig. 11 that the parts are so arranged as to slide within the housing ||2, permitting the entire assembly to be readily inserted and removed. When the parts are assembled as shown, they may be held in fixed positions as by means of longitudinally ex-A tending bolts or studs |3| which pass through all of the unitsand serve to hold the units against relative angular displacement as well as relative axial displacement.

The operation of the form of the invention just described is similar to the operation of the unit illustrated in Fig. 2 except that power to the lower units is not transmitted through a common crank shaft but is instead transmitted through the drive shafts |08, |09 and ||0 to the individual crank shafts ||8 of each of the subamato From the foregoing it will be observed that I.

have provided a novel pump assembly which is characterizedv by the use of a pulsator unit oi' a reciprocating character and acting as a hydraulic transmission to transform the rotary energy oi' an electric motor or other suitable power source into reciprocating fluid energy to operate the reciprocating pumping elements for raising the crude oil to the ground surface.

It will also be noted that I have shown three novel tvpes of crude oil pumping assemblies, each of which operates to maintain a substantially continuous flow of pumped fluid and each of which avoids the disadvantages of conventional reciprocating pumps in that all sliding motions are eliminated, no barrels and plungers are used to become scored or stick or leak because of sand, grit or other foreign material in the pumped fluid.

While I have shown and described the preferred embodiment of my invention, I do not desire to be limited to any of the details of construction shown or described herein, except as defined in the appended claims.

I claim:

1. A deep well submersible oil well pump comprising a prime mover, at least three piston pulsators actuated by the prime mover and having different cycles, means defining a plurality of pump chambers corresponding in number to the piston pulsators, an expansible member disposed within each pump chamber, valved inlets and outlets for each pump chamber for pumped fluid, and conduit means independently connecting each pulsator to the interior of a separate one of said expansible members, characterized by an absence of valves or other restrictions, whereby the interior of each expansible member and the conduit associated therewith may be filled with a power transmitting fluid so that the expansible members will enlarge in response to a piston pressure on the fluid to give a pumping action in each chamber and will contract when the fluid pressure is relieved by the piston.

2. A deep well submersible oil wel] pump comprising a prime mover, a plurality of piston pulsators actuated in synchronism and in phase by said prime mover, means defining a pumpchamber, an expansible member disposed within said chamber, valved inlets and outlets for said chamber for pumped fluid, and conduit means connecting the interior of said expansible member with all of said pulsators, whereby the interior of said expansible member and said conduit means may be filled with a power transmission fluid to expand and contract said expansible member in response to pulsating pressure produced by said pulsator.

3. A submersible oil well pump comprising an elongated housing adapted to be lowered into the well bore and attached to the lower end of a string of oil flow tubing, said housing enclosing a prime mover, a plurality cf piston pulsators disposed one above the other in said housing actuated in by an absence of valves or other restrictions. A

whereby the interior of said expansible member and said conduit means may be filled with a power transmission fluid to expand and contract said expansible member in response to pulsating pressure produced by said pulsator.

4. A submersible oil well pump comprising an elongated housing adapted to be lowered into the well bore and attached to the lower end oi' a string of oil flow tubing, said housing enclosing a prime mover, at least three piston pulsators, means connecting said piston pulsators to said prime mover for synchronous actuation but spaced in phase by a fraction of a full cycle equal to the reciprocal of the number of said pulsators, means defining a plurality of pump chambers corresponding in number to the piston pulsators and arranged one above the other in said elongated housing, anv expansible member disposed within each pump chamber, valved inlets and outlets for each pump chamber for pumped fluid, said outlets all being connected to said flow tubing, and conduit means independently connecting each pulsator to the interior of a separate one of said expansible members, characterized by an absence of valves or other restrictions, whereby the interior of each expansible member and the conduit associated therewith may be filled with a power transmitting fluid so that the expansible members will enlarge and contract in overlapping succession in response to alternating piston pressure on the power fluid to give a pumping action in each chamber and produce a continuous flow of pumped fluid in said flow tubing.

5. A submersible oil well pump comprising an elongated housing adapted to be lowered into the well bore and attached to the lower end of a. string of' oil flow tubing, said housing enclosing a prime mover. a plurality of sets of piston pulsators, each set comprising at least three of said pulsators. said sets being arranged one above the other in said elongated housing, means connecting said piston pulsators to said prime mover for synchronous operation with corresponding pulsators in all of said sets operating in phase and with the pulsators within each set displaced in operating phase by a fraction of a full cycle equal to the reciprocal of the number of pulsators ln each set, means defining a plurality of pump chambers corresponding in number to the piston pulsators in each set and arranged one above the other in said elongated housing, an expansible member disposed within each pump chamber, valved inlets and outlets for each pump chamber for pumped fluid, said outlets all being connected to said flow tubing, and a conduit for each expansible member, each of said conduits interconnecting corresponding piston pulsators in each set and connecting the interconnected pulsators to the interior of the corresponding expansible member, said conduit means being chaarcterized by an absence of valves or other restrictions, whereby the interior of each expansible member and the conduit associated therewith may -be filled with a power transmitting fluid so that the expansible members will enlarge and contract in overlapping succession in response to alternating piston pressure on the uid to give e. pumping action in each chamber and produce a. continuous flow of pumped fluid in said flow tubing.

6. In a multiple-acting submersible oil well pump mechanism; a. housing supporting said mechanism; a tubular member connected to said housing having valve-controlled intake and discharge ports for oil to be pumped; a. plurality of ilexible, contractible and expansible elements housed in said tubular member; and instrumentalities in said submersible pump housing for pulsating operating uid under controlled pressure in and out of each of said elements to produce a substantially continuous pumping action.

BENJAMIN F. SCI-MDT.

REFERENCES CITED The following references are of record in the me of this patent:

Number Number UNITED STATES PATENTS Name i Date Hoster Mar. 30, 1880 Stitzei Aug. 14, 1883 Constantinesco Jan. 9, 1917 Jones Feb. 28, 1922 Holt A pr. 5, 1932 Mantle June 27, 1933 Erwin Dec. 24, 1935 Pelich July 12, 1938 Schmidt Jan. 13, 1942 Schmidt Apr. 14, 1942 Meyers Aug. 4, 1942 Rodman et a1. Aug. 8, 1944 LeClair May 29, 1945 FOREIGN PATENTS Country Date France 1912