US2049315A - Well pump operating mechanism - Google Patents

Description

`uy 28, 1936. E. W. PATTERSON 2,049,315

WELL PUMP OPERATING MECHANISM Filed Aug. 10, 1952 2 sheets-sheet 1 67 .Z720 fzfor. 2f Edgar. MPa/remera .my 28, w36.

E. PATTERSON 2,049,3l5

WELL PUMP OPERATING MEGHANISM 2 Sheets-Sheet 2 Filed Aug. lO, 1932 74 Invem/Ur.

Edgar: Z/Z Elfe/50212 Patented July 28, 1936 PATENT oFFlcE 2,049,315, WELL PUMP OPERATING IWECHANISM Edgar W. Patterson, Long Beach, Calif., assignor, by mesne assignments, of one-half to Charles M. OLeary, Hollywood, Calif., and one-half to Margaret D. Patterson, Long Beach, Calif.

Application August 10,

6 Claims.

This invention has reference to well pump operating mechanisms, the principal objects of the invention being directed toward improvements over the usual walking beam pump operating apparatus. l

The principal object-of the invention is to provide an apparatus of this character which departs from walking beam rigs in such respects as to afford many comparative advantages from standpoints of both structure and operation and among these objects, particular importance 1s attached to the provision of a power equalizing system for the-pump operating beam, whereby the general operation and eiiiciency of such mech- 15 anisms are materially improved, and the load requirements in the motor or prime mover evened to the extent of `avoiding wide variations in the load andcorresponding variations in the power input `to the motor.

The various V'objects and vimprovements embodied in the invention Lwill perhaps be explained most readily and to `best advantage without necessity for further preliminary discussion, from the following .detailed description of a typical 25 and preferred form of the invention. K

Reference is had throughout the description to the accompanying. drawings, in which: L

Fig. 1 is a side elevation showing a pump operating mechanism embodying the invention;

Fig. 2 is a sectional plan taken on line 2 of Fig. 1; I

Figa is an? end elevation of the mechanism as viewed .from the right in Fig. 1;

Fig. 4 is al fragmentary`enlarged section show- 35 ing the air cushion cylinder and plunger assembly in detail; n

Fig. 5 is a fragmentary enlargedview showing the lubricant carrying pocket at theA lower end of the plunger skirt; and

Fig. 6`is an enlarged section' on line 6-6 of Fig. 3.

Referring rst to Fig.`1,the pump operating mechanism, generally indicated at I0, .isshown to be arranged adjacent the well casing I I, the 45 latter extending up through the elevated derrick floor I2. The pump operating mechanism 'preferably is so constructed and 'arranged las to be supported on a single H-section base beam I3, the latter in turn resting on transversely extending I-beams I4, l5 and I6. 4The rocking beam supporting structure comprises'a` pair of posts Il interconnected at their lower ends by shaft I8` the centralI web beam I3 which extends through 4 and which provides alpivotal mounting for the posts.. The latter areinterconnected aty their 1932, Serial No. 628,124 (Cl. 267-1),

upper ends by shaft I9, the ends of which project beyond the posts to connect with diagonally extending braces 20 which are detachably fastened at 2| to I-'beam I6.

Gusset plates 22 are formed integrally with 5 the lower ends of the posts I1 and normally, that is with the posts in Vertical positions, rest on I-beam I5. Similar gussets 23 project from the opposite sides of the posts and are adapted to serve as stops to arrest tilting movement of the 10 posts I1, as will more fully appear hereinafter.

A horizontally extending rocking beam 24 is pivotally mounted for vertically oscillatory movement on the central portion of shaft I9, the outer end of the beam carrying the usual segment 25 which is positioned above and in substantially vertical alinement with the head of the well casing I I. As will be understood by those familiar with the art, segment 25 serves as a means for connecting the rocking beam with the well pump rod and the rod clamp and supporting cable, all of which are diagrammatically indicated by the line 26. The pump rod 26 extends downwardly through a packing gland IIa in the Well casing head II b and connects with a vertically reciprocating pump plunger, not shown at the bottom of the well. The well pump is operated by imparting vertically oscillatory movement to the rocking beam 24 through the driving mechanism which I shall now describe.

A motor 28 is mounted on a platform 29 extending between posts I 1,.the platform being vertically adjustable to regulate positioning of the motor relative to the gear reduction mechanism to which I later refer. The vertical adjustment for platform 29 may be of any suitable character, and is shown typically as comprising bolts 30 supported on hangers 3I and extending through the top iianges of angle members 32 constituting integral parts of the platform at the outer sides of the posts. Motor 28 and the platform 29 may be moved vertically by adjusting nuts 33. In the present instance, the motor is mounted in such position that the motor driven pulley 34 has its axis substantially in 45 alinement with the center of post I1.

A gear reduction 35 is placed at the base of posts I1 and beneath the motor 28, pulley 36 of the gear reduction being driven from the motor by way of belts or chains 31. In order to stabilize the operation of the drive mechanism and to render the load and power requirements on the motor more uniform throughout the complete operating cycle, a y wheel 38 is placed on the shaft of the gear reduction. As win be noted in Fig. 1, the

arranged in the-relative positions illustrated in 5 order that when the post I1 and the rocking beam are tilted away from the well casing and to inoperative positions, the driving connection between4 the motor and the rocking beam will be rendered inoperative. By virtue of the relative oiset of "the motor and reduction gear pulleys 34 and 36, it will be seen that as posts I1 are tilted on shaft I8 to the dotted line position I1a, the distance between the two pulleys will be reducedto such an extent that the belts 31 will slip on the pulleys, l5 and the drive between the motor and gear reduction will be inoperative. v

A pair of crank sprockets 4I) are `mounted at opposite sides of the base beam I3, the sprocket shaft 4I being journaled in a bearing 42, see Fig. 2, attached on the top surface of the beam.

Crank wheels 4I) are driven from a pair of sprockets 43 on the gear reduction 35 by way of chains 44. Crank wheels 40 are operatively connected with the rocking beam 24 by way of connecting 25 rods 45 pivotally connected to the crank wheels by pins 46, and pivotallyattache'd to the walking beam intermediate its ends, by pin 41. The point of connection of rods 45 with the walking beam may beat any suitable point along the length of 'l the latter, although in the preferred form of the invention as illustrated, such point of connection isy at substantially the longitudinal center of the beam. 4 y

From a practical, standpoint, the described arrangement and mounting of the various parts of the mechanism on the single base beam I3 is of particular advantage, in that the structure is.

greatly simplified and rendered capable of ease in assembly and transportation where the mechanism is to be used as a portable pumping unit.

For purposes of transportation, the mechanism may be bodily moved, with necessity for making but few simple disconnections with the accumulator tank, hereinafter described. y'

In case it is desired to provide verhead clearance above the well head, as when'the pump rod is being pulled from the Well, the mechanism may be moved to one side by a simpleoperation, to

permit unobstructed operations above the well casing. As previously mentioned, posts I1 are supported for rocking movement on shaft Ill, al-

though normally the posts are rigidly held in their vertical positions by the diagonal braces 20.

When it is desired to move the end of the rocking beam from over the well casing, braces 20 may be disconnected from I-beam I6, and posts I1 rocked toward the left to the dotted line position I1a and the rocking beam likewise displaced to the left. Tilting movement of the posts is limited by gusset plates 23 coming to rest on I-beam I4. In its tilted inoperative position, the mechanism cannot be accidentally put into operation due toI ,the drive being disconnected as previously described. I preferably provide, in conjunction with the mechanism thus far described, a device for cushioning or resisting downward movement of the rocking beam, and while in the broad aspect of the invention any suitable device of this character may be utilized, I preferably provide an ,air power equalizing attachment whereby the power input is substantially evenly distributed throughout the 360 cycle or complete operating revolution of the device. 15 In its preferred form, the air power equalizing comprises a cylinder and plunger assembly, attached to the rocking beam 24 preferably at a'- pointintermediate its outer end and the point 41 lof, the'attachme'nt of the connecting rods there- Vwith. .j The assembly 5l) comprises a cylinder 5I 5 `v ,having a hanger 52 attached to its upper end and pivotally connected with the rocking beam by pin 53. A pipe 54 projecting upwardly within the lower interior of A the cylinder and annularly spaced from the wall-thereof, is carried on a 10 plate 55 attached to the end of the cylinder bybolts 56. The annular space 51 provides a lubri- -cant lcontaining chamber within which the lower portion of the plungerdips lto carry lubricant to the upper portion of the cylinder wall, as will l5 presently appear. Lubricant may be injected into the chamber 51 by way of a plugged opening at 58.

Plunger 59 is attached .to the upper end of tubular rod 60 extending through the lower end of the cylinder witha suitable clearance at 6I from pipe 20 54. The plunger may carry a series of rings 62 or any other suitable means for preventing leakprovide within the interior of the skirt an annular undercut groove 64, see Fig. 5, which serves essentially as a pocket to retain a. quantity of lubricant sufcient to carry through the travel' ci the plunger in the upper portion of the cylinder. 35 A plurality of ports 65 lead from the lubricant pocket 64 to a'shallow annular groove 66 'in the outer face of the plunger. Upon relatively upward movement of the plunger within the cylinder; the lubricant carried in pocket 64 feeds 40 through port 65 into groove 66 and into contact with the wall of the cylinder. It will benoticed that the lubricant is prevented from escape or leakage from the cylinder by being trapped in. the annular space 51, into which any excess lubri- 45 cant between the Working partswill drain.

The tubular plunger rod 60 has atits lower end a pivotalV anchor 61 which permits oscillatory movement of the rod as the cylinder 5I is vertically reciprocated by. the rockingbeam. An 50 accumulator or air reservoir 68 communicates with the compression chamber 63, within cylinder 5I,l through the tubular plunger rod and by way of pipe 69 connecting through pivotal joint at 10 with the plunger rod. Any suitable 55 connection may be made between the plunger rod and pipe 69, there being shownv as typical and preferred, however, a fitting 1I attached to the lower end of the rod.l and carrying trunnions 9| and 92 journaled in bearings 13 and 14. A 60 nipple 92 having a ilange 93, projects into the bore 94 of trunnion 9|, and a fluid tight joint between the parts is afforded by packing 95 conlined within bore 94 by flange 93. Oscillatory movement of the trunnion relative to the packing '65 is facilitated Without disturbing the packing, by inserting ball race 96 within the trunnion bore. Nipple, 92 is held in place and flange 93 kept in pressural engagement with the packing, by.a clamping ring 91 engaging the nipple ilange and 70 attached to bearing 414 by screws 98. By virtue ofthe described joint construction, free oscillatory movement of plunger rod 60 is permitted while in connection with pipe 69, and leakage at the joint effectively prevented. K

. B and D is one of acceleration in A valve 15 may be placed in line 69 to close oi communication between the cylinder and accumulator, and a second valve 16 placed in release nipple 11 through which, after valve 15 is closed, the air may escape from the cylinder. Thiscombination of valves is provided in order that in case it is desired to adjust the vertical position of the vertical movement of the rocking beam, such adjustment may be made without the necessity for having to exhaust the air from the accumulator. A

Air is supplied to" accumulator tank 68 by a suitable compressor 18, and the air pressure within the accumulator being maintained at a predetermined minimum pressure by means of a suitable pressure controlled switch S in the motor circuit and connected to the accumulator by line L. A pressure release valve for the accumulator is diagrammatically indicated at 19, and a blow-off connection at 80. The accumulator and compressor may be placed at any suitable location, although I preferably place them away from the derrick iioor in order to minimize obstructions around the well head.

Being operated through its connection with the crank wheels 40, it will be seen that the rocking beam 24 travels in simple harmonic motion in its vertical oscillatory movement, and that therefore that'the well pump rod 26 is operated in vertical simple harmonic motion. The travel of the crank pin 46 Within the angular interval between points A and B, see Fig. 1, is oneof acceleration in the rate of vertical movement of the crank pin, an-d therefore the rocking beam; Whereas the interval between pointsB and D is one of deceleration in the rate of vertical movement of the pin and rocking beam. Similarly, during downward travel of the crank pinand rocking beam, the angular interval between points the rate of downward movement, and the interval between E and A, one of deceleration. It follows therefore that during the intervals of acceleration between A-B, and- D-E, a greater load is'imposed on the motor, than during the intervals of deceleration.

A particularly outstanding feature of the invention resides in controlling the air` pressures in the air cushion cylinder and accumulator, so

as to minimize load variations on the motor and to generally increase the operating eiiiciency of the mechanism; It is further desired to main.- tain the air pressure in the accumulator and power equalizing cylinder at a predeterminedv value that will tend to even the load requirements on the motor in driving the rocking beam inE simple harmonic motion; or in other words to reduce the relative load variations on the motor between the periods of acceleration, corresponding to travels of the crank pin 46 in the intervals AB,D-E, and the periods of deceleration in intervals B-E and A-E.

It will be unnecessary to illustrate and to describe in detail, the characteristics of the usual single acting well pump, since the generalities of such pumps are well established and familiar to those in the industry. It may be noted that in the operation pf such pumps, the total load to be lifted will be the weight of the pump rods and pump parts attached thereto, plus the total weight ofthe fluid supported by the pump pump plunger or rod entailingv a downward pull on the beam is the weight of the understood from the following formulae in which L=combined total load, R=weight of rods, and F=weight of fluid. From -these values it will be seen that F+R=L.

Let A=air pressure, or rather the lifting force due to theair pressure, and assume the value of R to beA 1000 pounds, and the value of F to be 1000 pounds, the value of A will be 1500 pounds, or

Hence, during the up stroke of the beam, the load tobe raised is R-l-F or 2000 pounds. There Will be (R-f-Ff) -A, or 500 pounds of unequalized load to be lifted by the input power from the motor or prime mover during the up stroke. During the down stroke of the beam, the power requirement will be that necessary to move the pressure in the accumulator beam down against the lifting power of A, which will be 1500-R or 500 pounds. lowing power formulae apply:

Up Sroke R+F=2,ooo-A=5oo pounds Down stroke-A=1,500-R=500 pounds Thus the fol- Hence the power factor for both the up and down strokes is equalized, as noted in the above formulae. In actual practice, the equalization of power input may be carried out beyond the disclosures of the formulae, by regulating and controlling the variants of air pressure at different points throughout the cycle, as hereinafter described.

One purpose for providing an accumulator tank of substantially greater volume than the displace- \ment volume of cylinder 5I, that is, the volume .displaced by the plunger between the limits of .its stroke, is to prevent the building up of excessive air pressure upon downward movement of the rocking beam. In order to maintain or approach even distribution of load on the motor throughout the operating cycle, it is not intended that power should be expended only in moving the rocking beam down and that during this movement the air in the cylinder and accumulator shall be compressed to the point that the rocking beam will be raised at the desired rate of movement by air pressure alone, and without taking power from the motor.

On the contrary, it is intended that the volume of the accumulator will be such that excessive building up of air pressure will not result upon the downward movement of the rocking beam, so that excessive power will not be required from the motor during this half of the cycle, and that while the compressed air will aid the motor in moving the rocking beam through its upward travel, part of the load, at the desired acceleration, will be taken by the motor. It is found in average practice, the desired pressure conditions can be maintained within the system, by providing an accumulator having a volume of from 15 to 20y times the displacementl volume of the cylinder 5l.

In describing the operation, it may be assumed o thatthe rocking beam is starting on its downward movement, with crank pin 46 moving in a clockwise direction from point D. The angular interval of travel between points D and E is one of acceleration, and a greater load is imposed on the motor than between the interval E-.A of deceleration. In the intervals D-E, however, less resistance is offered by reason of compression of the air in chamber x63 during the corresponding rst half of the downward travel of the cylinder,

since the air pressure in the system is lower than that existing during the second half of the downward movement. lThus there is a compensation for the variationv in load requirements on the motor between the intervals D-E and E-A,'in that during the former interval of acceleration and in which the higher load requirements exist, lessresistance is oered by the compressed body of air, whereas during the interval E-A of deceleration, in which' the load on the motor decreases substantially, the resistance offered by compression of the air during the last half of the cylinder stroke has increased to theextent of maintainingA a'load on the motor.

In the upward movement of the rocking beam,

the power requirements of the motor during the v interval A--B of acceleration, and therefore greatest load, is. decreased by reason of the upwardv pressure exerted on the cylinder 5I by the compressed air. During the second half of the upward travel, corresponding to the deceleration interval B D, the pressure of the compressed air will have decreased to the point at which power willbe required from the motor to complete the upward travel of the rocking beam at the desired rate of Amovement- From the foregoing it will be seen that at no interval in the operating cycle, is the 'motor free from load, nor is itv driven through reverse operation of the mechanism so as to result in power input back into the line. It will also be observed thatin view of the reduction in variations of the motor load throughout the cycle, caused by control of the air pressure, the power requirements of the motor throughout the operating cycle will not be susceptible to abrupt changes, and the power curve of the motor will be relatively even.

Of all the factors to be reckoned with in the pumping of a well from great depths, only one is constant, and the rest are variables, the constant or known quantities being the rod and plunger weights. However, where the actual lifting torques can be calculated as in a pump' ing device of the character disclosed where the rod and plunger weights are known, and the exact pressurein the system under which power equalization is obtained, may also be closely predetermined, by proper regulation, all the variables such as friction, specific-gravity of fluid,

'portion of the cylinder .and into which the plunger skirt dips upon its relative 'downward movement within the cylinder, said wall also forming an air passage freely venting said reservoir to the atmosphere from above the liquid in said reservoir.

2. In well pumping apparatus having a verti- 5 cally extending air cushion cylinder attached to an oscillatory rocking beam, the combination comprising a plunger within said cylinder, a downwardly extending skirt on said plunger, and a wall forming with the cylinder an annularA lubricant containing reservoir withinthe lower portion of the cylinder and into which the plunger skirt dips upon its 4relative downward movement within the cylinder, the space occurring above the lubricant confined within said reservoir being freely vented to the atmosphere throughout substantially the full range of the plunger travel.

3. In well pumping apparatus having a vertically extending air cushion cylinder attached to an oscillatory rocking beam, the combination comprising,4 a plunger within said cylinder, a downwardly extending skirt on said plunger, a plunger rod extending downwardly through the cylinder, and an annular wall within the lower portion ofthe cylinder forming a lubricant containing reservoir into which the plunger skirt dips, said wall being annularly spaced from both the plunger rod and the plunger skirt when the latter is in its relatively downward position in the cylinder, the space occurring above the lubricant confined within said reservoir being con-` tinuously vented to the atmosphere through the space between said wall and the plunger rod.

4. In a well pumping apparatus having a rocking beam oscillating with relation to a fixed base, a' cylinder pivotally dependent from the freeend of the rocking beam, a piston rod pivotally connected to the fixed base, a piston carried by the rod reciprocating within the cylinder, an end wall extending across the lower end of the cylinder and through which the piston rod reciprocates, an upwardly extending sleeve mounted at its lower end on the end wall and with the lower portion of the cylinder forming av liquid lubricant reservoir, said sleeve extending to a point higher than the level of the liquidin the reservoir and having an inside diameter materially greater than the outside diameter of 'the piston rod whereby a free circulation of air may take place from the reservoir to the atmosphere at all times, a skirt formed, on the piston and adapted to telescope over the upwardly extending portion of the sleeve and to dip into the liquid lubricant at its lower end whereby liquid may be carried upwardly thereby, the inside diameter of the skirt being greater than the outside diameter of the sleeve to permit continued communication of the reservoirvwith the atmosphere.

5. In a well pumping apparatus having a rocking beam oscillating with relation to a fixed base, a cylinder pivotally dependent from the free end of the rocking beam, a tubular piston rod pivot-v ally connected to the xed base, a-piston carried by the rod reciprocating within the cylinder; an end wall extending across the lower end of the cylinder and through which the tubular piston rod reciprocates, an upwardly extending sleeve mounted at its lower end on the end wall and with the lower portion of the cylinder forming a liquid lubricant reservoir, saidsleeve extending to a point higher than the level of the liquid lin the. reservoir and having an inside diameter materially greater than the outside diameter of r may take place from the reservoir to the atmosphere at all times, a skirt formed on the piston and adapted to telescope over the upwardly extending portion of the sleeve and to dip into the liquid lubricant at its lower end whereby liquid may be carried upwardly thereby, the inside diameter of the skirt being greater than the outside diameter of the sleeve to permit continued communication of the reservoir with the atmosphere, a uid connection to the lower pivotal end of the piston rod, and a fluid passageway from the upper end of the piston rod through the piston whereby flow "of compressed fluid within the cylinder may take place.

6. A counterbalancing device for use with the' phere.

Walking beam of a well pumping mechanism, said device comprising the combination of va cylinder, piston and piston rod, constituting an air f cushion in connection with the said beam, an air storage tank having connections with ,said cylinder for supplying pressure thereto constantly during operation, means for maintaining avpredetermined constant pressure in said tank, a manually controlled cut-01T Valve in said connections, and a manually controlled exhaust valve for the cylinder located between the latter` and the said cut-off Valve, said valves. being operable to disconnect the cylinder from the tank pressure and to bleed the cylinder to the atmos- EDGAR W. PATTERSON.

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