US2664824A

US2664824A - Pumping unit

Info

Publication number: US2664824A
Application number: US130981A
Authority: US
Inventors: Fincher Louis
Original assignee: Lufkin Foundry & Machine Compa
Current assignee: Lufkin Foundry & Machine Co; Lufkin Foundry & Machine Compa
Priority date: 1949-12-03
Filing date: 1949-12-03
Publication date: 1954-01-05
Anticipated expiration: 1971-01-05

Description

L. FINCHER 2,664,824

PUMPING UNIT 2 Sheets-Sheet 1 Jan. 5, 1954 Filed Dec. 5, 1949 "Fig. I

. w 7 xi? Louis Fincher 85m 6 GM Fig. 2

L- FINCHER PUMPING UNIT Jan. 5, 1954 2 Sheets-Sheet 2 Filed Dec. 3, 1949 Fig. 3

v at Fig. 4

Patented Jan. 5, 1954 PUMPING UNIT Louis Fincher, Lufkin, Tex., assignor to Lufkin Foundry & Machine Company, Lufkin, Tcx., a

corporation of Texas Application December 3, 1949, Serial No. 130,981

, 7 Claims. 1

This invention relates to a counterbalancing Dumping unit which is adapted to counter balance the variation of work load between the lip-stroke and the down-stroke of a vertically operable pump, as, for example, the pump employed for removing fluid from a well.

It is an object of this invention to provide a pumping unit of this class which counterbalances a variation in work load between the up-stroke and the down-stroke of a vertically operable pump, as for an oil well, by maintaining a constant balance between the fluid pressure in a closed system, including a power cylinder at the top of the well, and the compressed air pressure which operates against the fluid pressure.

It is another object of this invention to provide a pumping unit of this class which is adapted to control the vertical elevation to which the piston within the power cylinder ascends so as to control the level at which the bottom hole pump plunger operates at the bottom of the well.

It is also an object of this invention to provide a pump which when driven in one direction by. a prime mover, has means therein for self-reversing its direction of discharge so as to alternately discharge fluid into a power cylinder and into a surge tank.

It is another object of this invention to provide a pumping unit of this class in which a selfreversing pump is adapted to deliver more fluid in one direction of discharge than is delivered in the other direction of discharge.

It is still another object of this invention to provide a pumping unit of this class which has control means therein for maintaining a predetermined balance between the compressed air pressure in an air tank and the fluid pressure in the surge tank of a closed fluid system to which the air tank is connected.

Other and further objects will be apparent when the specification is considered in connection with the drawing, in which:

Fig. 1 is a plan view of the pumping unit;

Fig. 2 is an elevation of the pumping unit taken along line 2-2 of Fig. 1; v

Fig. 3 is a sectional elevation of the self-reversing pump as taken along line 3-3 of Fig. 1;

Fig. 4 is a fragmentary sectional elevation of the self-reversing pump taken along line 4-4 of Fig. 1; and

Fig. 5 is a diagrammatical view of the operation of the pressure control device of the pumping unit. y

The pumping unit I comprises a base 2 having :mounted thereon a vertically extending hydraulic cylinder 3 which has a piston 4 therein, the rod 5 of the piston being adapted for connection to the top sucker rod 6 of a sucker rod line which leads down into a well and is connected to a pump plunger, not shown, which picks up fluid at the bottom of the well and transfers it to the top thereof.

The cylinder 3, near the top thereof, has a series of vertically aligned valves 8 connected thereinto and a line 9 leads from these valves into a reservoir ID. A scavenger pump II is mounted above the reservoir and picks up fluid from the line I2 and discharges it through a line I3 into a surge tank I 4. The surge tank has a line I5 connected into the top thereof which leads to air cylinders [6 which have air under pressure supplied thereinto by the compressor I1 mounted on the base 2 of the unit I.

The self-reversing pump I8 is mounted for convenience on top of the reservoir I0 and is connected to the surge tank I4 by means of the line I9, and into the power cylinder 3 by means of the line 20 which connects thereinto near the cylinder bottom slightly above its base 2|. A prime mover 22, as a gasoline engine, drives, by means of the chain or V-belt 23, the sheave 24 which drives the self-reversing pump I8. The scavenger pump II may, for purposes of convenience, be mounted on the end of the selfreversing pump I8 as shown in Figs. 1 and 2, and means may be provided for also driving this pump by the prime mover 22. Optionally it may be driven by a separate drive means as a small motor, not shown. The sheave 24 also has the chain or belt 26 connected thereto to drive the compressor, as shown in Figs, 1 and 2.

As shown in Fig. 1, the compressed air tanks it are supplied by the same compressor Il. These tanks, by means of cross-bars 28, may be connected to the power cylinder 3 so that the air tanks I6 and the power cylinder 3 are crossbraced for structural purposes near the top of the air cylinders and substantially centrally of the power cylinder. To complete the structurally braced triangle of members, the compressed air tanks have outlets 29 which connect into a T 30, into which is connected the line I5 to the surge tank I4. A suitable valve 3| is provided between the self-reversing pump I 8 and the line 20, and a valve 32 is also provided in the air line I5 between air tanks and the surge tank I 4.

The self-reversing pump I8 as shown in Figs. 3 and 4 may be of substantially the construction disclosed in my co-pending application for a Self- Reversing Rotary Pump, Serial No. 98,287, filed June 10, 1949, now Patent No. 2,625,105. Either of the modifications disclosed in this co-pending application may be employed but preference is given to the modification of Figs. 8-11 thereof since this model of the self-reversing pump is adapted to deliver more fluid in one direction of discharge than it delivers in the other direction.

This preferred pump, as disclosed in my Figs. 3 and 4, comprises an outer housing 40 which has a closure plug 4! therefor having threaded holes 42. therein. A boss 43 is provided which has bored and counterbored holes 44 therein so that the boss may be adjustably positioned at any of several points on the closure plug by means of the screws 45. An inner housing 46 is mounted 3 on the backingplate I47. which is connected: to be driven by a transmission, notshown, whichis mounted on the shaft 48. This transmission may be of any conventional type. The inner housing has opposed

ports

49 and 59 therein whicharecof peller rotates with the shaft 43 and *ata greater -speed than does theinner' housing- Aft-which is driven by thetransmission; not shown.

"The outer housing efi hasopposed connections '53 and-d thereinwith connection axis extend- 'ing substantially perpendicular -to the axis through the bosses A3 and 5| Theouter housing "also has compartments 55* and 55 thereinwhich are in communication with the slots and 58 respectively. A wall 59 separates the compartments and has the valve seat t9 therein which is" controlled by the valve BI. Another valve, not shown, is mounted to control the valve seat- 62 in the wall 59;this valve extendingoppositelyfrom the valve BI and opening'zintheopposite' direction in'the compartment 55.

The outer housing also has 's1ots-"E3-and :54 similar to the slots- 5'! and 58, and "allor these slots are tapered in decreasing size toward the bosses A3 and 5 l.

Let us assume as a starting point that the port 490i the inner housing is adjacent the' 'connection 53, and the port 5ll'isadjacentfthe connection 54. Then-withthe-impeller'. 52 and the inner housing rotating'in a clockwise direction as shown-by the: arrow-in" Figli 3,-'fluid first :enters' through the connection 53-= and -.is*dis charged out through :the :connection #54. When the inner! housingihas rotated: to the posit-ien shown in Fig; 3,1fiuid circulates as shcwnby the arrows; PEJTt'iOf theifiuidtaking. a'path through 'the' outer housing; through :the port ifi of the inner housing; through-the impeller, andont through the. port '50. of ithetinner housing :into the outer. housing. The other portion of -the fluid'takes a similar pathithrough the outer housingon the rightside of the pump; through the port '49, through .the impeller; and out :through the port 59 intothe outer housing. It should be noticed that in :this type: of: pumpithe" ports 49 .and .50" have; greater peripheral width than the bosses El :and 431ands consequently; are'never .closed. With :this: construction theldeceleration as the inneri mousing-5. approaches the position shown in Fig. 3,,and thesacceleration asit moves away from thisrposition,v is :very gradual; Then, as the. inner housing .46 andi'the impelleritt'continue clockwise rotation pastithe position 'of'Fig. 3, the direction. of'l fluidfflowiais reversed, port communication withzthe outer. housing spaceincreases; and. fluid flow accelerates.

A Shouldit be desiredi'ito. discharge more' fluid through one connection than is discharged through the othericonnection; it is only necessary to adjust the position iofithe boss 43. Should the boss be moved'tothe left hand side 'of the housing fill more fiuid will bGZZdlSChELIgEd out 'of the right hand side of the outer housing throughthe connection 54 than; is discharged through the connection 53 on' the oppositestroke.

TThis is obvious since positioningof the boss 43-to the leftshortens the opening betweentthe "boss anal-the inner housing lzthrough which the "fluid passes on the left hand side of the pump and increases the width of the opening between "the boss 43 and the inner housing 43 through "fluidzfithrough' the compartment 5 3 which the fluid may circulate on the right hand side of the pump.

Should the pump tend to deliver an excess of over the amount which may be discharged out there- -through,:ther:excess fluid will circulate into the compartment 55, lift the valve SE from the seat "tiljandrecirculate into the left hand side of the compartment. Should the pump tend to discharge more fluid out ofthe connection 53 than can be received "out 'therethrough, the excess fluid will circulateinto the compartment 56, lift a valve,-not'shown from the seat 62 and discharge throu'ghthecompartment 55 and into the right hand side-of the pump. 1 This over-load feature isnot' limited to the-form 0f over-load valve disclosed, but: any conventional over-load means may-be employed forthispurpose.

This invention includes a control system "which is adapted 'to compensate for the dinerences in loads placeduponthe pumping unit on :the down-strokeand on the up-stroke. The

-load'- on the up-stroke is greater than on the down-strokeas. on:the up-stroke the unit must 'clift a weight of fluid plus the weight of the plunger .at the. bottom of the well and the weight of the sucker'rods extending therefrom to the top of =.the well, z-and'must. also overcome friction, where- ;asonathe down-strokeitheweight of the sucker rodsea-ndplunger; are lowered abetted by the force of gravity.

'i'To counterbalance :this variation in load oc curring in the=operationofithe'pumping unit as a result of thertransfer-tof: a'volume ofifiuid from :thesurge. tankinto: the-.ipower cylinder on the up-stroke, and the return of;this fluid to the surge ta'nkionthe down-estrokemompressed air is maintained in air;tanks 'Which-communicate with the 'top; ofdahe surge. tank;-,.and balance is obtained thereby.

As the fluid isitransferredfrom the comparatively 5small volume surge, tank into the power :cylinderbnsthe upstroke, there is no appreciable pressure dropinitheisurgetank as a result thereof, sincesthe comparatively extra large volume of air in the air tankspermits the air to occupy the space evacuated byithe fluid with no noticeable reduction of the pressurefimthe air tank-surge .tanksystem. Thiszisctrue eventhough the pressure; developed in the powerunit on the up-stroke is about two hundled-pounds persquare inch and on the; down-stroke; about one. hundred. pounds per square inch. ,Qneachup-stroke of the power cylinder, work is being. done accelerating the sucker 1 rod 1 string. and the toil fluid column thereabove: inworderato transientheoil :from the well to storageitanks. S; Consequently-the difference in fluid pressureiin the powergcylinder, as developed on the up-stroke, and that occurring on the .down-.stroke,-= is translated:v into actual work done onthe up-stroke.

Should there be an increase of the load which the pumping, unit has to-v lift, or should there be leakagefrom.thecompressed air tank, an over balance .inafavon of. the .fluid. pressure occurs so thatthe plane of equalization between fluid pressure..and;air...pressure occurs higher in the surge tank thanthelevel of a desired plane of equalization. "on theother hand, sh0u1d an excess of air pressure .deyelop,. ,as .by the ,lowering ofv the well load, or by an increase in the temperature .of the air, then there will be an over-balance in favor of air pressure, and the plane of equalization will occur at a lower point in the surge tank, and below the predetermined plane at which equalization is sought. To compensate for such occurrences, and to strive at maintaining the plane of equalization at a predetermined desired level, the automatic regulating device of this invention is provided.

The device by which the equalizatio is obtained has a cylinder II with a piston I l therein, the piston having the rod '15 connected thereto and there being a spring 56 inserted around the rod to bear against the piston, an end plate i3 then being fitted on over the rod 5 to close the cylinder. The spring 70 is then inserted into the cylinder from the other end thereof; the adjustment device 80 is threaded into the end plate I2 and then the assembly of device and end plate is fitted to the cylinder II so that the adjustment plate 82 bears against the spring 19. As the rod BI is threaded, the rotation thereof moves the plate 02 inwardly 0r outwardly to vary the tension of the spring against the piston I4.

A line 85 is connected into the cylinder II near the end plate 72 and this line leads to the power cylinder 3 of the powe unit I which is to be counter-balanced. A line 8?, in turn, is connected into the cylinder 1| on the opposite side of the piston I4 from the line 04 and leads to the compressed air tanks I6. Each air tank in turn being connected as hereinabove described, by means of a line 29 to the T 30, from which the line I5 leads to the surge tank I4.

A second cylinder 0| is provided which is closed by end plates 02 and 93 and which has the spool type piston 94 therein with the piston rod 05 therefor extending through the end plate 03; the opposite end plate 92 having therein the vent or discharge 96. A line 91 from the air cylinders I8 is connected at opening 98 to the cylinder 0| and diametrically opposed thereto in the cylinder is the opening or vent 09. Th line I 0! branche off from the line 9'! and connects into the cylinder 9! substantially centrally thereof and opposed to the line IOI, on the side thereof in the direction of the openings 08 and 99, is another connection I02.

The lines NH and I02 are so spaced and of such size that they may both open at the same time into the space surrounding the reduced diameter I03 of the spool piston I06 When the piston is located as shown in Fig. 5. There is another connection I0 3 into the cylinder 9! adjacent the end plate 02 and the connection I02 joins this connection and a common lead I05 connects therefrom into the clutch H6.

The clutch H6 is of any conventional type which is adapted to be expanded upon the admission of air thereinto to clutch the hub of the sprocket use. As the clutch is keyed to the shaft of the compressor H0, and as the sprocket I00 is mounted to rotate freely on this shaft when the compressor is idle, the engagement of the friction surface of the clutch with the sprocket hub causes the sprocket I00 to drive the compressor. This type of arrangement is conventional and one structure therefor is disclosed in detail in my co-pending application, Serial No. 130,982, filed of even date herewith.

The piston rod i5 has two stops I 00 and I0? slidably adjustable thereon, and a lever I08 has the head I00 thereof mounted to slide along the rod so as to barely contact these stops at either end of th stroke when a previously correct relationship has been manually set betweenpressure in power cylinder 3 and air tanks I6 for the particular well load. This lever I 08 is pivoted at I I I, and has a forked prong II2 to fit around a pin I I3 on the piston rod I5.

I operation, should the fluid pressure in the power cylinder 3 exceed the value at which the range of the predetermined balance with the compressed air pressure has been established, such pressure pushes the piston 14 to the right to bring the stop I06 on the piston I5 into contact with the lever head I09. This, in turn, pivots the lever I08 about its pivot III so that the fork H2 thereof pushes the rod and the spool piston 94 to the left, to place the connection IOI in communication with the space around the reduced diameter of the spool I03, and the discharge connection I02 is also placed in communication therewith so that compressed air from the cylinders I6 passes through the cylinder I03 and through the connection I05 into the clutch, not shown, to engage the sprocket I00 to drive the compressor H0.

The prime mover 22 then drives the sheave 24, and from thence, through the belt 26, the sprocket I00, and the compressor H0, builds up the air pressure in the cylinders I 6, and this compressed air discharges through the line 8'! to build up pressure on the right side of the piston 14 to move the piston 14 to the left.

This leftward motion of the piston 14 moves the stop I06 on the piston rod 15 so that it again barely contacts the lever head 59 at the end of the stroke. Thus the rod I5, as it returns to travel within the normal zone, slides along through the head I09 and pivots the lever I08 in a direction to move the fork H2 to the right, thereby causing the spool piston 94 to cover the connection IM and to uncover the connection I 04. This cuts off compressed air from the clutch I06 and permits the air that has been forced thereinto to bleed out through the lines I05 and I04 and back through the cylinder 0| and out through the vent or discharge 96. This breaks the contact of the gripping surface of the clutch I06 with the sprocket I00, and stops the compressor H0.

Should the air pressure in the cylinders It in crease with relation to the fluid pressure in the power cylinder 3, the piston 14 will be moved substantially to the left by the entry into the cylinder 1 I of air under pressure through the connection 87. This results in the piston rod 75 moving to the left to bring the stop I0? into contact with the lever head I 09 so that the fork I32 moves the piston rod 95 and spool piston 94 to the right to place the connection 08 and connection or vent 99 into communication with the space around the reduced diameter I03 of the spool so that compressed air from the cylinders I6 bleeds through the cylinder 9| to the atmosphere and reduces the pressure in the right-hand side of the cylinder II, thereby permitting the piston 14 to move back to the normal position of Fig. 5. When this occurs it follows that the piston I4 closes the connection I02 as well as the connection I 0|.

As conditions vary widely in well pumping operations, the adjustment device 00, hereinabove described, is provided to adjust the length of piston travel for the varying requirements of various wells, so as to keep the stroke length within the capacity of the regulating device. Thus turning the thread rod 8| so as to move the plate 82 inwardly preloads the springs 16 and 19 for a ta-s24,

" given load" "variation, fiend "shorte s the 'pi ston a'averana outward motionof theplate 82 in the control cylinder H 'lengthens'the' piston travel.

piston in the powercylinder at the top of the well'may rise; 'which is adapted to deliver more fluid into the power cylinder on one stroke, as

on the up-stroke -than on the down-stroke, by means of a self-reversing pump driven by a prime mover which'rotates' the impeller thereof in one direction'onlyfand' this invention further considers such apumping' unit having an automatic control orregulating device which is adapted to maintain the plane. of equalization between the fluid and compressed air in the surge tank of the unit at a predetermined level.

'What is claimedis:

1f A counter-balancing pumping unit comprising, a vertically extending power cylinder, a piston therein, means connected to the cylinder and adapted for connection to a bottom hole pump plunger, a plurality of vertically aligned discharge valves in said power cylinder at substantially the top thereof, a surge'tank, liquid return means connected to said valves for returning liquid from above said piston to said surge tank, a self -reversing pump for-transferring liquid back and forth between said power cylinder below said piston and said surge tank,"an air cylinder, a compressor for supplying compressed air to said air cylinder, a line for connecting said air cylinder and surge tank, control means responsive to liquid pressure in -said power cylinder below said piston to start and stop said compressor and to bleed air from said air cylinder to maintain a counter-balance between compressed air pressure and power cylinder liquid pressure below said piston, one of said valves being open" while the others are closed to limit upward piston travel and said self-reversing pump having means therein to permit the pump to discharge-more liquid in one direction than in the other direction.

2. A counter-balancing pumping unit comprising, a power cylinder having a piston operable therein, means connected to said power cylinder for regulating the travel of said piston therein, a surge tank, means for transferring liquid from said piston travel regulating means to said surge tank, an air cylinder connected tO-said surge tank, a compressor for supplying air to said air'cylinder, a pump adapted while being driven in one direction to alternately transfer unequal amounts of liquid back and forth between said power cylinder and said surge tank, control'means responsive to power cylinder liquid pressure and air cylinder pressure to counter-balance air and liquid pressures in said surge tank, and means for driving said pump and said com-pressor.

' 3. A' counter-balancing pumping unit comprising," a power cylinder having a piston operable therein, means connected to said power cylinder for regulating the travel of said piston therein, a surge tank, means for transferring liquid from said piston'travel regulating means to said surge tank, an air cylinder connected to said surge tank; a 'compres's'orfor'supplying' air to said air cylinder, a pumpadapted while being driven in one direction to alternately transfer unequal amounts of liquidback and forth between said power 'cylind'erand said surge tank, and control m'eans responsiveto' power cylinder liquid pressure and air cylinder pressure to counter-balance air and liquid pressures in said surge tank.

4. A counter-balancing pumping unit comprising, a power cylinder having a piston operable therein, means connected to said power cylinder for regulating the travel of said piston therein, .a surge tank, means for transferring liquid from said piston travel'regulating means to said surge tank, an air cylinder connected to said surge tank, a compressor for supplying air to said-air cylinder, and a pump adapted while being driven in one direction to alternately transfer liquid back and forth between said power cylinder and said surge tank.

5. 'A counter-balancing pumping unit comprising, a power cylinder having a piston operable therein, a surge tank, means for transferring liquid from said piston travel regulating means to said surge tank, an air cylinder connected to said surge tank, a compressor for supplying air to said air cylinder, a pump adapted while being driven in one direction to alternately transfer liquid back and forth between said power cylinder and said surge tank, control means responsive to power cylinder liquid pressure and air cylinder pressure to counter-balance air and liquid pressures in said surge tank, and means for driving said pump and said compressor.

6. A counter-balancing pumping unit comprising, a power. cylinder having a piston operable therein, a surge tank, means for transferring liquid from said power cylinder to said surgetank, an air cylinder connected to said surge tank, a compressor for supplying air to said air cylinder, a pump adapted while being'driven in one direction to alternately transfer unequal amounts of liquid back and forth between said power cylinder and said surge tank, and control means responsive to power cylinder liquid pressure and air cylinder pressure to counter-balance air and liquid pressures in said surge tank.

7. A counter-balancing pumping unit comprising, a vertically extending power cylinder, a piston therein, means connected to said power cylinder and adapted for connection to a bottom hole pump plunger, a surge tank, a self-reversing pump for transferring liquid back and forth between said power cylinder below said piston and said surge tank, an air cylinder, a compressor for supplying compressed air to said air cylinder, a line for connecting said air cylinder and said surge tank, and control means respcn sive to liquid pressure in said power cylinder below said piston to start and stop said compressor and to bleed air from said air cylinder to maintain a counter-balance between compressed air pressure and power cylinder liquid pressure below said piston.

LOUIS FINCHER.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,879,262 Hubbard Sept. 27, 1932 1,897,002 Carroll Feb. 7, 1933 2,072,595 Hutchison Mar. 2, 1937 2,185,448 Suter Jan. 2, 1940 2,247,238 Johnston June 24, 1941 2,251,290 Reed Aug. 5, 1941