US2291880A - Single-acting hydraulic pump - Google Patents

Description

Aug- 4, 1942-- c. J. coBERLY l ,2,291,880

S INGLE-ACTING HYDRAULIC PUMP Filed Aug. 2, 1940 2 Sheets-Sheet 1 y HA RR/s mech/,FOSTER aHA/e/.s

67 I Q. Fg THE F/.PM'

/4 TORLVEY 2 Sheets-Sheet 2 c. J. co'vBERLYl SINGLE-ACTING HYDRA'ULAIC PUMP Filed Aug. 1940 Aug. 4, 1942.

Patented Aug. 4, 1942 smear-.acume f Clarence S. Coberly, Los cles, C.,

to Roko Corporation, Reno, Nev., a cotation i of Nevada Application August 2, 1940, Serial No. 350,010

(Cl. 10S-46) l Claims.

This invention relates to uid operated pumps for wells, and more particularly to a single-act-` ing pump of such type.

This invention is an improvement over the device disclosed in my Patent No. 2,081,220, issued May 25, 1937, to which reference is hereby made.

Fluid operated pumps are of particular utility in producing oil from wells, and, consequently` the present invention will be described in connection with such use, although it is to be understood that my invention is susceptible of other and diierent uses and that I do not intend to be limited by the specific use of the embodiment described herein.

In the fluid operated pump art, hydraulic pumps adapted to pump from deep wells are normally complicated in construction, such as thev device described in my said Patent No. 2,081,220, requiring many parts and being expensive to manufacture. By reason of the relatively complicated construction of such prior art devices, the relatively high cost of such apump pro,- hibits its use in oil wells in which the production is very low, commonly termed stripper wells in the art. It is therefore a primary object of my present invention to provide a hydraulic pump having a materially simplified construction so that the same can be economically operated in wells of low productivity.

It is a further object of my invention to provide a hydraulic pump of very small diameter so that it may be used in well tubing of small diameter, thus reducing the cost of well tubing for a well installation. Such an object'has been impractical to accomplish with prir art devices, due to the relatively high minimum practical limits of diameter thereof, as the complexity of such prior art pumps and the practical manufacturing considerations involved therein have normally required external diameters of at least two inches. am able to provide a deep Well pump having a maximum diameter of one and one-quarter inches or` even less at less cost than has formerly been the case.

I have further discovered that where only a small well production is possible, for example lessA than fteen barrels of oil per day, it is impractical to use the ordinary type of hydraulic pump in which the motor and pump pistons are of relatively large diameter, because for such' use the pump 'is required to be operated very slowly to maintain the pump production below the normal productivity of the well. Obviously, if the pump By using my present construction, I

ductlvity, the pump will soon reduce the level of fluid in the well to a point at which it is below the pump intake, thus causing the pump to pump merely air or gas, which is undesirable, and therefore if a hydraulic pump of the prior art type normally intended to produce a high capacity 'is used, it must be slowed down substantially to insure production of the desired low capacity. When a reciprocating hydraulic pump is slowed down materially below the rate of recipro cation for which it has been designed, many disadvantages occur. chief of which is the tendency for the pump pistons to hesitate at the ends of their strokes, causing jerky operation, high stresses, and other dililculties, which are ,particularly apparent if the pump is being used to pump Awell oil or other relatively viscous fluid. This is normally caused by 'faulty valve action when the valves are operated at low speed. My present invention is further intended to obviate these disadvantagesA by providing a hydraulic pump of small capacity in which the pistons thereof are reciprocated at a speed suiiiciently high to give smooth operation without any tendency to hesitating at the ends of their strokes.

Still another object ci my invention is to pr'ovide a single-acting hydraulic pump including a reciprocating pump piston in which the pumping is accomplished on the upstroke of the pump piston and the downstroke of the pump piston is insured by the application of operating iluid under high pressure thereto independently of the pressure exerted by the column of pumped iluid.

Other objects and advantages of my invention will be evident from the following specification and the drawings, which are for the illustration only, and in which:

Fig. 1 is a diagrammatic v iew of my pump unit for the purpose of clearly illustrating the general construction thereof.

Fig. 2 is a vertical sectional View of the upper portion of my invention..

Fig. 3 is a vertical sectional view of the central part of my device, extending downwardly from the bottom of Fig. 2. y

Fig. i is a vertical sectional view of the lower part of my device, extending downwardly from the lower end ofFig. 3.`

Fig. 5 is an enlarged cross-sectional view taken on the line of Fig. 3.

Fig. 6 is an enlarged cross-sectional View taken on the line G-- of Fig. 3.

Fig. 'I is` an enlarged cross-sectional view taken purpose of production is greater than the normal wellproon the line lof Fig. 3.

Fig. 4il is an enlarged cross-sectional view taken on the line 8-8 of Fig. 4.

Fig, 91s an enlarged cross-sectional view taken on the line 9-9 of Fig. 4.

Fig. 10 is an enlarged cross-sectional view taken on the line Ill- I of Fig. 4.

Referring to the drawings, I show the lower end of a production'tubing I5 which is normally disposed in a well so that the lower end thereof is materially below the normal level of fluid in the well, the production unit being provided at its lower end with a conical seat |6. Suspended within the production tubing on power tubing |1 isa fluid operated pump unit I8.

At the upper end of the uid operated pump I8, there is provided a tubular valve housing I9 having a minor bore 29 and a major bore 2|. Secured in the lower end of the major bore 2|, as by shrink tting or otherwise, is a valve sleeve 22 formed so as to provide an annular space 23 therearound between the valve sleeve and the major bore, the space being adapted to receive a slidable valve member 24 having a major portion 25 and a minor portion 26, the major portion tting into the annular space 23 and the minor portion fitting into the minor bore 20 of the valve housing |9. Formed in the valve housing I9 are a plurality of radially disposed upper exhaust ports 21 communicating with the upper end of the major bore 2|, and also connected with the upper portion of the major bore by an annular recess 28 is a longitudinal fluid passage 29 extending downwardly to the lower end of the valve housing I9. Also formed in the valve housing I9 is a longitudinal discharge passage 30 communicating between the lower end of the valve housing and a discharge port 3|.

The valve member 24 is provided with a plurality of radially disposed intake ports 33 communicating through a spiral groove 34 formed in the inner surface of, the valve member with a counterbored recess 35' also formed therein, which in turn communicates through a passage 36 formed in the lower portion of the valve member with the bottom of the valve member. Formed in the valve sleeve 22 are a plurality of radially disposed upper ports 31, a plurality of radially disposed lower ports 38, and -a plurality of radially disposed intermediate ports 39, the purpose of which will be described hereinafter. The lower ports 38 communicate through an annular channel connecting the same formed in the valve sleeve 22 and an opening 40 in the lower end of the valve housing I9 with the discharge passage 30. Also provided in the valve housing I9 is a port 30a communicating between the passage 30 and the upper intake ports 33. Threaded to the lower end of the valve housing I9 is a tubular motor barrel 42 provided therein with a liner 43, the liner being uted as shown in Fig. 6 to provide longitudinal uid passages 64 between the motor barrel and the liner. I'he upper end of the liner 43 abutsagainst a spacer member 45, the upper end of which in turn abuts against the lower end of the valve housing I9 and the valve sleeve 22. The spacer member is provided with a bore :i6 within which extends the lower end of the valve sleeve 22, and is provided with a counterbored portion 41 at its lower end. The spacer member 45 is provided with a longitudinal passage `48 communicating at its upper end with the discharge passage 30 and communicating at its lower end with an annular recess 49 formed in the lower end Qf the spacer member. Although only one espeso passage 48 and one upper discharge port 3| arel shown, it will be understood that additional passages 48 may be annularly disposed in the spacer member 45 and that additional discharge ports 3| may be provided as desired. The lower portion of the spacer member 45 has a reduceddiameterso as to provide a fluid space 56 between the spacer member and the tubular motor barrel '42, the upper end of which communicates through a groove 5| formed in the spacer member with the fluid passage 29 of the valve housing I9. The lower end of the fluid space 50 communicates directly with the longitudinal passages 44 formed vbetween the motor barrel 42 and the liner 43.

The lower end of the motor barrel 42 is threaded to a pump housing 55, the upper end of which telescopes into the motor barrel and rigidly abuts against the lower end .of the liner 43. 4Formed in the upper end of the pump housing 55, which constitutes the lower end of the motor cylinder, are fluid ports 56 communicating between the interior of the pump housing and the longitudinal uid passages 44 through an annular recess 51 formed in the outer surface of the pump housing. As will be noted, the internal diameter of the pump housing 55 is, in the embodiment shown, the same as the internal diameter of the liner 63. The lower end of the pump housing 55 is threaded to a seat plug 58 having a beveled seat 59 formed on the lower end thereof adapted to seat in the conical seat I6 of the production tubing I5. An annular seat ring 60 formed of lead, rubber, or other suitable material, is provided in the beveled seat 59 so as to iorm a fluid-tight joint between the seat plug 58 and the conical seat I6 of the production tubing |5. The seatplug 58 is provided with an axial bore 6| having a. valve seat ring 62 provided at the upper end thereof on which is adapted to seat a ball valve member 63 normally held in seated engagement with the valve seat ring 62 by a spider 64 held in engagement therewith by a compression spring 65 disposed between the spider and a valve cage 66, these valve parts constituting a standing valve means 62a of my invention. The lower end of the axial -bore 6| communicates through an opening 61 formed in the lower end of the production tubing I5 with the fluid in the well to be pumped.

Provided in the liner 43 is a, motor piston 68 having an axial iluid passage 69 therethrough, the upper end of the piston being counterbored to'rigidly receive a head element'10 having a central passage' 1| communicating with the axial iiuid passage 69 and also communicating through horizontal openings 12 formed in the head element with the annular recess 49 of the spacer member 45. Suitable piston rings 13 are provided on the outer face of the motor piston 6Il so as to form a sliding fluid-tight fit between the motor piston and Athe interior of the liner 43.

, Threaded into the head element 10 is an upper piston rod element 14 which extends upwardly through the valve sleeve 22 and the valve housing I9 into the power tubing I1, making a fluidtight lit with the valve sleeve. The piston rod element 14 is provided with a plurality of lower grooves 15 formed around its outer surface and a plurality of upper grooves 16 also formed therein, for a purpose to' be described hereinafter.

Connected to or preferably formed integral with the motor. piston 68 is a central piston rod element 18 of smaller diameter than the motor piston, the lower end of which forms apump plunger 80, being slidably received in a pump liner 8l rigidly ilxed in the pump housing 55 and having suitable packing rings 82 in the upper end thereof adapted to form a fluid-tight seal with the pump plunger'88. As shown, the pump plunger 80 is of the same external diameter as the central poston rod element 18 and slightly smaller than the motor piston 68, thus forming a differential acting pump in the construc-v tion shown. It will be apparent to one skilled in the art, however, that the size relation between the diameters of the motor piston 68 and pump plunger 88 may be varied as desired to meet any condition found in a particular well installation without departing from the spirit of my invention.

The pump plunger 88 includes what is known in the art as a travelling valve mechanism 83 comprising a tubular valve seat member 84 on the seat of which a ball valve member 85 is adapted to be normally engaged by a spider ele. ment 86 held in engagement therewith by a spring B1 engaging a, working valve cage 38, as is understood in the art.

In operation, my invention operates as a sinsure of the column of pumped uid in the production tubing i5, the upper face of the motor piston being at all times in open iluld communication with the interior of the production tubing through the annular recess 39, the longitudinal passage 48, the discharge passage 3E), and the discharge port 3l, the lower face of the motor piston being in communication with the interior ofthe production tubing through the iluid ports above the motor piston 68. Some iluid from above the standing valve mechanism 82a may also be displaced upwardly through the passage I8. During the downstroke of the motor lpiston 8 8, the valve member 24 will remain in the-position shown in Figs. 1 and 2, because any high pressure operating fluid leaking downwardly around the upper piston rod 1B will be exhausted through intake ports 83, the port 38a, the discharge passage 30,'and the discharge port 3i, into the column of pumped iluid, thus prevent operating iiuid from reachingv the lower end of the valve member 24 during the maior part of the downstroke of the motor piston 88.I

As the upper piston rod element 18 nears the lower end of its stroke, the upper grooves 16 formed` at the top thereof will communicate with the upper ports 81 formed in the valve sleeve 22 to permit operating uid under high pressure to flow from the power tubing l1 downwardly through the valve housing I9. the upper grooves 16 on the upper piston rod element 18, the upper ports 81, the counterbored recess 35, and the passage 38, to the lower end of the valve member 24. Although the upper end of the valve member 24 is at all times exposed to the high pressure of the operating uid in the power tubing l, due

. to the fact that the area of the lower end thereof 56, the annular recess51, the longitudinal uid passages 44, the iluid space 56, the groove 5|, the iiuid passage 2S, the upper end of the :major bore 2i, and the upper exhaust ports 21. Consequently, the fluid pressure exerted on the upper and lower faces of the motor piston 68 will be equal, and the upper end of the major portion 25 of the valve member 28 will beopen to the relatively low pressure oi' the pumped fluid through the exhaust ports 2l.

The power tubing l1 is at all times lled with operating iluid under relatively high pressure, conveyed downwardly therethrough to the iiuid operated pump unit i8 from a suitable source of high pressure iiuid (not shown), and it will be noted that the upper piston rod element 1d is at all times subjected to the pressure exerted by the operating uid in the Apower tubing. Consequently, with the parts shown as positioned in the drawings, the pressure of the operating uid exerted on the upper piston rod element l@ will cause the same together with the motor piston t8 and the pump plunger 88 connected thereto to move downwardly, thus producing the downstroke of the piston and plunger. As the pump plunger 88 moves downwardly, well iiuid trapped above the standing valve mechanism @2a in the pump sleeve 8i will cause the ball valve member 85 of the travelling valve mechanism 83 to move o the seat to permit the'well fluid to pass upwardly into the axial uid passage SQ to nil the same with wen uuid and to an the space in the liner se is considerably greater than the area of the upper end thereof, and the upper end of the major portion 25 of the valve member is always open to the exhaust pressure in the column of pumped fluid, through the ports 21, when the high pressure fluid communication is opened as described to the lower end of the valve member, it will cause the same to move upwardly until the major portion 25 thereof engages the upper end ot the major bore 2l of the valve housing i9. As soon as the valve member 2t starts its upward movement, the major portion 25 thereof soon covers the annular recess 28 to close communication between the fluid passage 29 and the exhaust ports 21. As the valve member 2d nears the upper end of its stroke, the intake ports 33 therein will register with the annular recess 28, thus opening iiuld communication between the uid passage 2@ and the operating iiuid under high pressure in the power tubing l1 through the upper end of the valve housing I8. Operating uid under high pressure will then flow through the intake ports 33, the annular recess 28, the fluid passage 28, the groove 5l, the fluid space 58, the longitudinal uid passages t6, the fluid ports 58, into the lower end of the liner 63 so as to apply operating uid under high pressure to the lower face of the motor piston G8. This causes the motor piston to perform its upstroke carrying with `it the central piston rod element H8 and the pump plunger 88 attached to the lower end thereof. During the upward movement of the pump plunger 88, the travelling valve mechanism 33 will lbe closed, and the well duid above the motor piston 88 will be raised and discharged through the annular recess 139, the longitudinal passage 68, and the discharge port ai, into the interior of the production tubing i5. Upward movement of the pump plunger produces a suctien. therebelow in the pump sleeve 8i, causing the standing valve mechanism 62a to open to permit a lfresh supply of well fluid to flow into the pump sleeve through the axial bore Si and the opening b1.

As the upper piston rod element 1d approaches its uppermost position, the lower grooves 'it therein bridge the intermediate ports 3d and the lower ports te so as to afford uuideemmunication between the lower end of the valve member Il and the relatively low pressure iluid in the discharge passage 30 through the intermediate ports 3l, the lower ports 38, the grooves l5. the discharge port 40, and the discharge passage Il. This reduces the pressure beneath the valve member 24 to the pressure of the pumped fluid in the production tubing I5,.which is materially below the pressure of the operating iiuid in the power tubing i1, and the pressure of the operating fluid in the power tubing acting on the upper end of the valve member causes the same to move downwardly to the position shown in Fig. 2, thus again opening the lower face of the motor piston llto the column of pumped iluidin the production tubing as described hereinabove.

Since the difference in area between the lower end of the motor piston 68 and the pump plunger 80 is preferably relatively small, the capacity of my fluid operated pump per stroke may be quite low, thus permitting my construction to be used where it is desirable to maintain the reciprocation of the motor piston and .pump plunger 'at a relatively high rate and still ail'ord only a relatively low production capacity from the device. It will also be apparent that with the construction illustrated, a fluid operated pump may be constructed having a relatively small external diameter. By this construction I am able to produce fluid operated pumps having an external diameter of less than one and one-quarter inches. which is substantially less than the minimum external diameter practical with fluid operated pumps of types well known in the prior art.

Although I have shown and described my construction in its preferred embodiment, it will be understood that certain parts and mechanisms thereof are the equivalent of other parts and mechanisms which may be substituted therefor without the exercise of invention, and that the size relationship between mana1 of the parts thereof may be substantially varied without departing .from the spirit of my invention, and I therefore intend to be afforded. the full scope of the following claims.

I claim as my invention:

l. In a fluid operated well pump, the combination of: a column of uid in a well under relatively high pressure; a column of fluid in a well under relatively low pressure; a motor cylinder having a motor piston therein having a fl-uid passage therethrough, the upper side of said motor piston being at all times in communication with said low pressure column through a pump outlet communicating between the upper end of said motor cylinder and said low pressure column; a pump cylinder having a pump piston therein having a fluid port therethrough; a travelling valve in said pump piston; a standing valve communicating with said pump cylinder below said pump piston; -hollow connecting means operatively connecting said pistons and affording fluid communication between said fluid passage and said fluid port; a rod member attached to the upper end of said motor piston and extending into said high pressure column; means piston thereupon being moved in the other direc- 5 nation of: a column of duid in a .'well under relatively high pressure; a column of fluid in a well under relatively low pressure; a motor cylinder having a motor piston of relatively large diametertherein having a iluid passage therethrough,

1o the upper side of `said motor piston being at all times in communication with said low pressure colunm through a .pump outlet communicating between the upper end of said motor cylinder and said low pressure column; a pump cylinder having. a pump piston of relatively small diameter therein having a fluid port therethrough; a travelling valve in said pump piston; a standing valve communicating with said pump cylinder below said pump piston; hollow connecting means operatively connecting said pistons and ailfording fluid communication between said fluid passage and said fluid port; a rod member attached to the upper end of said motor piston and extending into said high pressure column;

:means for connecting the other end of said motor piston with said high pressure column to admit operating fluid from said high pressure column to said other end of said motor piston to move the same in one direction; and means for connecting said other end of said motor piston with said low pressure column so as to equalize the iiuid pressure on the ends of said motor piston, said motor piston thereupon being moved in the other direction by said rod member due to iluid pressure exerted on said rod member by said high pressure column.

3. In a iluid operated pump, the combination of: a column of fluid lin a well under relatively high pressure; a column of liuid in the well under relatively low pressure; a valve housing connected to said high pressure column; a motor cylinder connected to said valve housing therebelow and being in fluid communication -with said low pressure column at all times through a 45 pump outlet communicating between the upper end oi said motor cylinder and said low pressure column; a motor piston in said motor cylinder having a passage therethrough communicating with the upper end of said motor cylinder; a

pump cylinder connected'relative to said motor cylinder and therebelow; a pump piston in said .pump cylinder having a passage therethrough; hollow connecting means connecting said pistons and said passages; a rod member attached to the upper end of said motor piston and extending upwardly through said valve housing into said high pressure column; valve means in said valve housing for alternatively connecting the lower end of said motor piston with said high pressure column and with said low pressure column; and means operating in response to movement of said rod member to actuate said valve means.

4. In -a fluid operated pump adapted to be operated in a well having a supply column of fluid at relatively high pressure and a .production column of fluid at relatively low pressure, the combination of: a' cylinder; piston means in said cylinder and having opposed ends of substantially equal Iareas;- inlet means for admitting well iiuid from the well to one end of said piston means; passage means providing fluid communication -between said end of said piston means and the production column at all times; valve means adapted to open iiuid communication between the other end of said piston means and alternately the production column and the supply column; and piston rod means connected to said one end of said piston means and having an area exposed to the fluid pressure in said supply column when the said other end of said piston means is in iluid communication with said production column.

5. In a fluid operated pump adapted to be operated in a well having a supply column of fluid at relatively high pressure and a production column of uid at relatively low pressure, the combination of a cylinder; piston means in said cylinder and having opposed ends; inlet means for admitting well fluid from the wellto one end of said piston means; passage means providing fluid communication between said end of said piston means and the production column at all times; valve means adapted to open iiuid communication between the other end of said piston means and alternately the production column and the supply column; and piston rod means connected to said one end of said piston means and having an end exposed to the fluid pressure in said'supply column when the said other end of said piston -means is in fluid communication with said :production column.

6. In a iluid operated pump adapted to be operated in a well having a supply column of iluid at relatively high pressure and a production column of fluid at relatively low pressure, the combination of a cylinder; piston means in said cylinder and having opposed upper and lower ends; inlet means for admitting well fluid from the well to said upper end of said piston means; passage means providing fluid communication between said upper end of said piston means and the production column at all times; valve means adapted to open fluid communication between the lower end of said piston means and alternately the production column and the supply column; and piston rod means connected to said upper end of said piston means and having an area exposed to thefluid pressure in said supply column when the lower end of said piston means is in fluid communication with said production column.

'7. In a duid operated pump adapted to be operated in a well having a supply column of fluid at relatively high pressure and a production column of fluid at relatively low pressure, the combination of: a cylinder; piston means in said cylinder and having opposed ends; inlet means for admitting well fluid from the well to one end of said piston means; passage means providing fluid communication lbetween said end of said piston means and the production column at all times; valve means above said cylinder and adapted to open fluid communication between the other end of said piston means and alternately the production column and the supply column; and piston rod means connected to said one end of said piston means and extending upwardly through said valve means, and having an upper end exposed to the fluid pressure in said supply column when the said other end of said piston means is in fluid communication with said production column.

8. In `a fluid operated motor adapted to be operated from a supply column of fluid at relatively high pressure and having a low pressure discharge, the combination of: a cylinder; .piston means in said cylinder; valvemeans adapted to open iluid communication between one end of said piston means and alternately the low pressure discharge and the supply column, said piston means moving in said cylinder in one direction when communication is opened between said one end thereof and said supply column; passage means .providing fluid communication between the other end of said piston means and said low pressure discharge; piston rod means connected to said piston means and having an end exposed to the high pressure fluid in said supply column so that when said one end of said piston means is in fluid communication with .said low pressure discharge the fluid pressure exerted by said supply column on said piston rod means will cause it to move said piston means in said cylinder in a reverse direction; and means for connecting said piston rod means and said valve means constructed and arranged so that movement of said piston rod means controls the operation of said valveA means.

9. In a fluid operated pump adapted to be operated in a well having a supply column of fluid at relatively high pressure and a production column of fluid at relatively low pressure, the combination of a cylinder; a tubular member extending downwardly from the lower end of said cylinder and having an opening communicating with the fluid in the well; piston means in said cylinder and having a tubular sleeve extending downwardly therefrom into said tubular member and making a sliding fluid-tight fit therewith,

therer being a longitudinal passage through said sleeve and said piston communicating with the upper end of said cylinder; port means connecting the upper end of said cylinder with said production column; standing valve means in said tubular member; working valve means in said tubular sleeve; valve means for connecting alternately the lower end of said cylinder below said piston means with said production column andsaid supply column; and'piston rod means connected to the upper end of said piston means and having an upper'end exposed to the fluid pressure insaid supply column. f'

10. In a fluid operated pump adapted to be operated in a well having a supply column of fluid at relatively high pressure and a production column of fluid at relatively low pressure, the combination of: aV cylinder; a tubular member extending downwardly from the lower end of said cylinder and having an opening communicating with the fluid in the well; piston means Y in said cylinder and havinga tubular sleeve extending downwardly therefrom into said tubular member and making a sliding fluid-tight iit therewith, there being a longitudinal passage through said sleeve and said piston communieating with the upper end oi said cylinder, said piston means having upper and lower working ends of substantially equal area; port means connecting the upper end of said cylinder :with said production column; standing valve means in said tubular member; working valve meansin said tubular sleeve; valve means for connecting alternately the lower end of said cylinder below said piston means with said production column and said supply column; and piston rod means connected to the upper end of said piston means and having an upper end exposed to the fluid pressureinsaid supply column.

CLARENCE J. COBERLY.

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