US2292427A

US2292427A - Long stroke pump jack

Info

Publication number: US2292427A
Application number: US300606A
Authority: US
Inventors: Luther A Blackburn
Original assignee: BERNHARD H SCOTT
Current assignee: BERNHARD H SCOTT
Priority date: 1939-10-21
Filing date: 1939-10-21
Publication date: 1942-08-11
Anticipated expiration: 1959-08-11

Description

Aug. 11, 1-942. L. A. BLACKBURN 2,292,427

LONG STROKE PUMP JACK Filed Oct. 21, 1939 2 Sheets-Sheet 1 PatentedAug. 11, 1942 7 2,202,427 LoNG STROKE PUMP JACK Luther A. Blackburn, Altadena, Calif., assignor of one-half to Bernhard H. Scott, Glendale,

Application October 21, 1039, Serial No. 300,606

9 Claims. (CI. 74-37) This invention relates to long stroke pumps, and the invention is particularly applicable in the construction of deep-well pumps. Deep-well pumps that involve the use of a reciprocating sucker rod or pump-rod actuated at the ground level are very inefilcient due to the lengthening of the rod on the up-stroke which, of course, reduces the efiective stroke.

The usual means for reciprocating the rod of 7 a deep-well pump is the well-known walking beam, but practical considerations make it substantially impossible to obtain with it a stroke of more than four or five feet. The present improvement involves the use of endless driving chains that operate to reciprocate a cross-head that is connected to the pump-rod. I am aware that chain drives have been suggested heretofore for this purpose, but they have not come into generaluse. This is probably due to the fact that they have not provided for properly counterbalancing the weight of the pump-rod. This involves considerable difficulties because of the fact that on the up-stroke the load on the driving chains includes the pump-rod and also the long column of oil surrounding the pump-rod above the standing valve which, of course, is open on the up-stroke.

An object of the present invention is to overcome these difi'iculties and to provide a chain drive capable of being constructed so as to enable a relatively long stroke for the pump-rod to be attained and at the same time provide for substantially perfect balancing of the load so that all of the forces acting on the cross head are substantially balanced with reference to the axis of the rod and also in such a way that substantially the same load is placed on the driving chains on the down stroke as well as on the up stroke. In this way the chains operate one. substantially constant load with the stresses always acting in the same direction in the chains.

A further object of the invention is to provide simple means for effecting constant lubrication of the chains.

A further object of the invention is to provide means for adjusting the bearings of the sprocket wheels supporting the chains to take up wear on the chains, and to accomplish this without interfering with the constant lubrication of the chains.

A further object of the invention is to provide adjusting means for the upper ends of the driving chains so constructed that it will provide means for imparting the entire load from the bearing "blocks of the sprocket chains to the 55' frame of the pump, at the same time providing simple means for efiecting their vertical adjustment when the same becomes necessary.

In its construction the apparatus includes oppositely disposed drive chains located on opposite sides of the path of the cross head that is attached to the pump rod. In order to drive the pump rod, blocks are employed sliding in a transverse slot in the cross head. One of the objects of the invention is to improvethe action in a construction of this kind to permit relative movement of the links that are connected to these blocks. This enables the chains to pass over the sprocket wheels without any danger of subjecting the connecting pin to any torsional strains.

A further object of the invention is to provide simple means for preventing whipping of the chains where the. chains must be-unusually long to provide for an extremely long stroke in the pump.

A further object of the invention is to provide means for facilitatingthe removal and replacement of the cross head from the cross head guide.

Further objects of the invention'will appear hereinafter.

The invention consists in the novel parts and combination of parts to be described hereinafter, all of which contribute to produce an eiiicient long stroke pump jack.

A preferred embodiment of the invention is described in the following specification, while the broad scope of the invention is pointed out in the appended claims.

In the drawings: Fig. 1 is a side elevation of a pumping apparatus embodying my invention, a portion of the cross head being broken away and shown partially in section.- Also portions of the chains are broken away so as to display the cross head and contiguous parts.

Fig. 2 is also an elevation showing the side of the apparatus, illustrated in Fig. 1. In this view certain parts are broken away and at the bottom of the figure the lubricating bath is illustrated in section, as also the cross head that is attached to the pump rod. In this view the upper end of the flow pipe is omitted and the pump rod is shown broken away.

Fig. 2a is a side elevation showing the lower end of the hanger bar such as I employ for suspending and effecting the upward adjustment of the bearing blocks for the upper sprocket wheels.

Fig. is a perspective of one of the blocks y pins or Y which I prefer to employ for imparting movement from the chains to the pump cross head.

Fig. 4 is a vertical section showing a length of flow pipe and pump rod.

Fig. 5 is a vertical cross-section taken about on the line 5-5 of Fig. 1 upon an enlarged scale, and particularly illustrating the preferred details of the construction for connecting the driving blocks that drive the cross heads, that is to say, for connecting the blocks to the opposed runs of the chains that drive the same.

Fig. 6 is a vertical section taken about on the line 6-4 of Fig. 1 upon an enlarged scale, and particularly illustrating the means for adjustably supporting the upper ends of the driving chains, that is to say, for supporting the bearing blocks for the sprocket wheels.

Fig. 'l is a horizontal secti n upon an enlarged scale taken about on the line 'I'| of Fig. l, and particularly illustrating the arrangement of the driving chains with reference to the cross head.

Fig. 8 is a horizontal section taken about the location of the line 8-8 of Fig. 1, upon an enlarged scale, certain parts being" broken away. This view particularly illustrates the means for driving the lower sprocket wheels that carry the driving chains.

Before proceeding to a more detailed description of the invention, it should be stated that in its preferred embodiment I provide for counterbalancinl; the cross head that is attached to the pump rod in such a way that the forces acting on the rod are always balanced with reference to the axis of the rod.

Also in the preferred embodiment of the invention I provide four endless driving chains disposed in opposite pairs so that the cross head of the pump lies between the pairs of driving chains, and in such a way that two driving blocks or pins attached to the chains are arranged to engage the transverse slot of the cross head. The direction of movement of the chains is such that on the upstroke these blocks are located near the pump rod and on the down stroke they are remote from the pump rod. At all times, however, these two blocks'are equi-distant from the axis of the rod so that the forces exerted by them on the cross head are perfectly balanced.

Although it is not essential to the invention to provide two separate counterweights, nevertheless I prefer to counterweight the pump rod in that way and these counterweights are located so that any strains developed by their presence are balanced. This tends to prevent the development of vibrations at the top of the frame, where the construction is of vertical type, disposed in such a way as to connect directly to the pump rod.

. The driving chains referred to above, at their upper ends pass over sprocket wheels and likewise at their lower ends, and at these points the driving blocks referred in above move apart or approach each other. These blocks are attached to special links of opposed runs of the chains. I provide a special construction for this connection that will permit relative swiveling movement of these special links with reference to each other, thereby improving the construcion.

The ends of the crosshead are guided by means of crosshead guides, and in order to facilitate the removal and replacement of the crosshead in the guides I provide a special construction for the guide that will permit this.

The bearing blocks that support the sprocket wheels at the ends of the chains, which of course support the entire load on the chains, are so constructed that while the pump is in operation an effective clamping of these bearing blocks is attained on the frame, enabling the entire weight.

of the load to be imparted immediately from the bearing blocks to the frame. At the same time the construction includes means for effecting an upward adjustment of the bearing blocks when .the pump is not in operation.

Referring more particularly to the parts, and especially the Figs. 1 and 2, I provide a frame i that is preferably upright and located directly over the flow pipe 1, and the pump rod 3 that extends up from the flow pipe, and which is reciprocated to pump the well. This frame i may be of any suitable construction, but is preferably made up of structural shapes such as angle iron. In order to form a guide for the cross head 4 that actuates the pump rod, I prefer to provide two angle irons 5 connected together back to back (see Fig. 8) forming a T-iron guide with superposed flanges 6 that can be engaged by the ends of the cross head 4 in some manner such as indicated in Fig. 7. The cross head is constructed with a deep transverse slot 8 (see Fig. 1). The pump rod 3 passes up from below across this slot and is secured to the cross head by means of a clamp 8 that is of the usual construction, including bolts, that can be released to enable the cross head to be adjusted to any desired position on the pump rod, or vice versa. This clamp fits closely into openings l0 formed in webs Ii projecting up from the upper side of the cross head so that there is substantially no play in transmitting movement to the rod from the cross head.

The chain drive for the cross head preferably comprises four endless chains l2. These chains are disposed in pairs as illustrated in Figs. 7 and 8. As shown, the chains of each pair are located respectively on opposite sides of the plane of movement of the c oss head. Corresponding runs of these pairs of chains are connected together by a connection I: (see Fig. 5) which connects the runs at the slot 8 of the cross head so as to drive the cross head up and down. This connection l3 could consist of a mere pin, but I prefer to construct it so that it includes a block l4 having an. opening or bore l5 through the same for a driving pin to pass through. Furthermore, the driving pin is preferably not constructed as a simple pin, but is 'so constructed as to give a certain amount of flexibility in the connection. This is desirable when the chain passes over the sprocket wheels at the upper and lower ends of the chains, as will be described hereinafter. Referring to Fig. 5, I prefer to provide two special links Ii in the chains, and these links l6 are connected together by a swivel pin connection, preferably comprising a solid pin ll secured to one of the links I6, which is received in the sleeve or hollow pin 18 attached to the opposite link. In addition to this swiveling movement, it is also preferable to construct'this connection so as'to permit the chains to move slightly'apart or toward each other.

This enables them to adjust themselves to the planes of roperfect balance. counterweighting means carried on the frame I,

2,292,427 In the operation of the pump, the inside runs 2| of the chains move upwardly, so that the blocks ll on the up stroke are located near the middle of the cross head. In this way. these lifting forces are brought nearer to the location of the pump rod which of course is at the middle of the cross head.

Although the blocks I B may have plain rubbing faces on their upper and lower sides, I pre-- fer to provide anti-friction devices such as rollers 22-in their faces (see Fig. 3). The inner ends of the blocks are preferably provided with vertical clearance grooves 23 that provide clearance for the pump rod that lies between these blocks on the up stroke.

In practising the invention I counterweight the cross head and the load carried by it in such a way that the force exerted by the counterweight is applied in such a way that a perfect balance results. In other words,- if a single counterweight were employed, the cable supporting it would be attached at the middle of the cross head and extend upwardly over a pulley at an elevated point above the frame, but not supported on the frame.

However, I prefer to provide and in this instance I prefer to provide two oppositely disposed counterweights 2 (see Fig. 1) supported on lines or cables 25 that pass upwardly from the counterweights and over sheaves or pulleys 26, the inner endsof the cables passing downwardly and being attached to cross-pins 21 on the cross head (see Fig. 7). I prefer to provide two of these cables 25 on each side (see Fig. 2).

Each counterweight 24 preferably consists of a plurality of weights stacked together and tied together with a tie-bolt 28 that passes through all of them. This tie-bolt should fit snugly in the holes in the weights and should be clamped tight by nuts 29 on the upper ends of the tie bolts. This prevents any possibility of the individual weights shifting out of line.

As the cables 25 are attached substantially at the middle of the cross-head on each side of the That would achieve weighed 9000 pounds, then the total load on the up stroke would be 18,000 pounds. In that case the counterweights should have a total weight of 13,500 pounds." This gives a net loadon the down stroke of 4500 pounds and a net load on the up stroke of 450 pounds. This enables the motor driving the chains to operate at a substantric motor, and this motor through. a belt 34 -equal diameter and meshing together.

drives a horizontal countershaft 35 (see Figs. 1

and 8). This countershaft extends across the frame, being supported by suitable bearings 36 and is provided with pinions 31 for driving the lower sprocket wheels 38 over which the sprocket chains run. In order to accomplish. thi in a simple manner and to drive thechains in the proper directions, the shafts 39 of the sprocket wheels 38 are provided with gear wheels 40 of One of these wheels meshes on its outer side with the sprocket wheel 31. By reason of the fact that the chains are driven at the base of the frame,

of course the vibration of the frame is greatly .reduced. This .greatly reduces any tendency sprockets are mounted in suitable bearings supsucker rod, they exert a directipull on the crosshead in perfect balance.

The counterweights are guided on the corner angle irons 30 in the manner indicated in Fig, 7, slide bolts 3| being provided. between the inner edges of the angle irons with keeper plates 32 bolted on each side of the flanges. This arrangement insures the proper guiding of these counterweights and prevents any lateral movement in them as they move up and down.

In order to maintain a constant load on the driving chains, that is to say, an unvarying load, these counterweights 2% have a weight that is substantially three-quarters of the total load on the cross head on the up stroke. For example, suppose that in a 6.000-foot well the weight of the pump rod is 9,000 pounds. In that case I would construct the pump so that the weight of the column of liquid being pumped is substantially equal to the weight of an equal length of the pump rod. In this connection reference is had to Fig. 4 illustrating a length of flow pipe and pump rod. In order to determine the proper relative diameters of the rod and flow pipe, it is merely necessary to proportion them so that the area of the rod multiplied by its specific gravity is equal to the area of the columnof liquid multiplied by its specific gravity. The result of.this

would be that, assuming that the pump rod of line so that they will not have any tendency to move further away from each other.

In order to maintain the chains and all parts working adjacent to them lubricated, I prefer to provide a lubricating bath or oil bath 43 (see Fig. 2) in which the lower ends of the chains dip.

. I prefer to provide a common oil bath for all four chains and permit the pump rod 3 to pass up through it. In order to accomplish this it is necessary to provide a sleeve or tubular housing that extends up from the bottom of the oil tank to a sufficient height to maintain the oil level above the lower ends of the chains. This avoids use of a stufiing-box,

As there will be considerable wear on the chains, so that they will tend to lengthen themselves, I provide means for adjusting the upperv o assist in I through horizontal flanges in a cross-bar the racks 49 preferably have upwardly and outwardly inclined faces which permit the cap 50 to ride over the same in an upward direction when the bearing blocks are being adjusted upwardly. The cap bolts 50 are secured in place by clamping bolts 52. Any suitable means may be provided for adjusting the bearing blocks 48 upwardly when the clamping bolts 52 have been loosened. However, I prefer to accomplish this by providing suspending hanger bars 53 (see Fig. 1), the upper ends of which are threaded and pass the frame. The threaded ends of these hanger bars carry adjusting nuts 55 that can be tightened up to pull the blocks 48 upwardly. The lower ends of these hanger bars 53 .have eyes such as the eye 56 illustrated in Fig. 2a. These eyes are formed at lower ends ofth hanger bars will enable them'to be attached to the blocks by bolts 51.

It may be necessary from time to time-to remove the cross head 4' for repairing the same, and in order to accomplish this I provide the cross head guide 5 with a removable section 58 (see Fig. 1), the ends'of which are maintained in alignment with angle irons that form this guide by means of clips such as the clip 59 secured in place by removable bolts.

-As the total weight of the apparatus is' not very great, even including the frame, it can be supported directly on the derrick floor 60. In order to give access to the upper end of the frame I, it may be provided with a small ladder ii at one side and also be constructed with a crows -nest 6| near the level of the sheaves 26 and in a position'from which the adjusting nuts 55 can be reached whenever it is necessary to adjust the upper sprockets.

The shafts of the lower sprocket wheels 38 are supported on inboard bearings 62 (see Fig. 8)- which are in the form of blocks and carried in the lower ends of channel bars "that are attached at their upper ends to cross bars 54 of the frame I.

In order to enable'the inertia of the counterweights to be overcome at the end of the down stroke, I provide the apparatus with means for attaining the effect of a flywheel. For this purpose I prefer to provide a flywheel 65 on each end of the shaft 35 (see Fig. 7).

In practice, the blocks l4 should have a depth of about three-quarters of the diameter of the sprocket wheels. This seems to facilitate their ease of travel in the cross-head slot 5. It is also desirable in practice to line the faces of the slot 8 with hardened steel wear strips 8a such as illustratd in Fig. 5.

At the bottom of the down stroke, the crosshead 4 dips in the oil bath. In practice, brushes (not illustrated) 'dip in the bath and wipe the guide 5 with lubricant. As the cross-head dips in the bath the sleeve 44 of the bath passes through a clearance opening 44a in the bottom of the cross-head. This is practicable because at this moment the blocks H are at the outer ends of the cross-head. Inpractice, the brushes should be located at the ends of the cross-head to dip in the lubricant and apply it to the guideways 6 on the up-stroke.

If desired. this apparatus can be used for pull- -ing the pump-rod. In doing this, it would be 1. In a long-stroke deep well pump, the combination of a frame, a flow-pipe in the well, a pump-rod extending down into the flow-pipe, a cross-head, a driving connection between the pump-rod and the cross-head, means for guiding the cross-head to reciprocate on the frame, four endless drive chains disposed in pairs with one drive chain of each pair located on one side of the plane of movement of the cross-head,and the other chain of that pair located on the other side of the plane of movement of the cross-head, a pair of driving-members for the cross-head corresponding to each of said pairs of driving chains and supported by the opposite runs or the said chains, a pair of oppositely disposed counterweights disposed one on each side of the axis of the pump-rod and guided to move in a substantially vertical direction on said frame, the weight of the counterweights being proportioned with respect to the weight of the pump-rod and fluid pumped, whereby the difierence in weight between the counterweights and the weight of the fluid pumped plus the weight of the rod string on the upstroke, is substantially equal to the difierence between the weight of the counterweights and the weight of the rod string on the downstroke of the latter to insure the maintenance of a constant load on the chains in the same direction throughout the reciprocatory movement of the pump-rod.

2. In a long-stroke deep well pump, the combination of a frame, a cross-head, means for guiding the same to reciprocate on the frame, a pump-rod, means for connecting the pumprod to the cross-head, four endless chains disposed in pairs with one chain of each pair located on one side of the plane of movement of the cross-head and the other chain of that pair located on the other side of the. plane of movement of the cross-head, a pair of driving members for driving the cross-head, connected to opposite runs of the said chains, means for driving said chains, and a pair of oppositely disposed counterweights disposed one on each side of the axis of the pump-rod, the weight of the counterweights being proportioned with respect to the weight of the pump-rod and fluid pumped, whereby the difference in weight between the counterweights and the weight of the fluid pumped plus the weight of the rod string on the upstroke, is substantiallyequal to the difference .between the weight of the counterweights and at the end of their down stroke.

.3. In a long-stroke deep well pump, the combination of a frame, a cross-head, a pump rod, means for connecting the cross-head to the pump rod to reciprocate the latter, driving means ineluding endless chains disposed on opposite sides of the plane of movement of the cross-head, a flow pipe in which the pump rod reciprocates,

. counterweights connected to said cross-head, the weight of the counterweights being proportioned with respect to the weight of the pump-rod and fluid pumped, whereby the diflerence in weight between the counterweights and the weight of the fluid pumped plus the weight of the rod string .on the upstroke, is substantially equal to the difference between the weight of the counterweights,

and the weight of the rod string on thedown stroke of the latter to. insure the maintenance of a constant load on the chains in the same direction throughout the reciprocatory movement of the pump-rod.-

4. In a deep well pump, the combination of a pair of drive chains, a pump rod having a driving cross-head between said chains, said cross-head having a transverse guide-way, a driving member, chains having special links, means connecting said driving member to said special links including a swivel connection permitting nelative movement of the two special links on a transverse axis between the chains and thereby enabling the chains to adapt themselves to any irregularities of faulty alignment in the chain supports or sprocket wheels for the same.

5. In a deep well pump, the combination of a pair of drive chains, a pump rod having a driving cross-head between said chains, said crosshead having a transverse guide-way, a driving member, chains having special links, means connecting said driving member to said special links including a swivel connection, said swivel connection including a pin secured to one of the links and a sleeve'receiving the pin and secured to the opposite link, said pinand sleeve cooperating to permit relative movement of the two special links on a transverse axis between the chains and thereby enabling the chains to adapt themselves to any irregularities or faulty alignment in the chain supports or sprocket wheels for the same.

6. In a deep well pump, the combination of a pair of drive chains, a pump rod having a driving cross-head between said chains, said crosshead having a transverse guide-way, a driving member, chains having special links, means connecting said driving member to said special links including a swivel connection, said swivel connection including a pin secured to one of the sleeve operating to permit a limited relative longitudinal movement of the pin and the sleeve.

7. In a pump jack for reciprocating a pumpactuating member, an endless chain comprising a plurality of links, a pair of sprockets for the support of said chain, means to move said chain over said sprockets, means to transmit the motion, in two opposite directions, of one of. said links during movement of said chain to said pump-actuating member, said last-named means including a lost-motion connection between said chain and said pump-actuating member to dissipate the motion of said link in a direction transverse to the motion transmitted to said pump-actuating member, and means to counterbalance a portion of the weight suspended from the cross head on the upstroke ofsthe latter, the weight of said counterbalancing means being in excess of the weight suspended from the cross head on the downstroke of the latter, said excess being, in terms of pounds, substantially equal to the uncounter-balanced portion 0! the weight suspended from thecross head on the upstroke of the latter.

8. In a well pump having a plunger, a cross head and means to connect said cross head to the pump plunger, 8, chain including a. special link, means to support said chain with opposite reaches extending vertically, means to drive said chain in one direction to move said link successively through said vertical reaches in opposite directions, means to connect said link to said cross head to reciprocate the latter, a counterweight connected to said cross head to Oppose the weight of said first-named means and the fluid in the well being pumped during the up stroke of the cross head, the difference between the weight of the fluid column pumped plus the weight of said first-named means on the upstroke and the weight or the counterweight being substantially the same as the diiference between the weight of the counterweight and said firstnamed means on the downstroke.

9. In a pump jack, a pair of vertically aligned sprockets, an endless chain carried by said sprockets with opposite reaches of the chain extending vertically, a string of sucker rods connected to said pump, said chain including an anchor link, connecting means to connect said link of said chain to the sucker rod string, drive means for one of said sprockets to move said link alternately through opposite vertical reaches of said chain, and a counterweight attached to said afore-mentioned connecting means to oppose the weight of the sucker rod stringand' of the fluid in the well being pumped to substantially equalize the tension on said chain through a complete cycle of the pump.

LUTHER A. BLACKBURN.