US2896458A - Well pumping device - Google Patents

Description

July 28, 1959 INVENTOR.

BY ROGER 8. WHITE I ATTORNEY United States Patent WELL PUMPING DEVICE Roger B. White, Van, Tex., assignor to The Pure Oil Company, Chicago, 111., a corporation of Ohio Application August 24, '1955, Serial No. 530,265

14 Claims. (Cl. 74-51) The present invention relates to an improvement in mechanical linkages connected between eccentric driving members and rotating driven members whereby straightline motion of variable sequence or stroke is obtained and made available to operate a plurality of secondary driven means, such as pumps, to more closely control the operation of the latter. More particularly the invention relates to a drive mechanism utilizing oscillatory members whereby the frequency and length of the stroke therefrom may be varied according to the demands on the equipment.

Although the present invention may be applied between any eccentric means and its associated pull rods, it is more clearly explained by relationship to the problem of varying the frequency and magnitude ofthe strokes of oil well pumps operated from a central power eccentric. Prime movers are generally used as a source of power for pumping numerous oil wells from a given location. Such installations are generally set up with the primemover operating through a gear box or transmission with a crank 'arm which rotates in a horizontal path. The outer end of the crank arm is pivoted to the table of an eccentric. The various pull rods which connect with the Wells are pivoted to the periphery of the eccentric table. The crank arm revolves at a rate of between and 30 revolutions per minute. The eccentric is carried in an oscillatory motion imparting to each point on its periphery a circular motion. Such mechanisms operate under adverse conditions and due to the fact that the length of pull rod to each well may vary and the depth of the various wells are never uniform, there is created an uneven pull upon such eccentric central power mechanisms.

Attempts have been made to equalize this uneven pull without success. The situation becomes even more critical when it is considered that each well is pumped on a certain schedule and from time to time the number of wells connected to the central power eccentric will vary.

This throws an additional unevenness into the stresses placed upon the eccentric. Often times when the pull rods of a well are disconnected from an eccentric, a

istransmitted throughout the various pump rods and affects the efliciency of the pumping in addition to increasing the wear on the component parts of the mechanism.

In addition to the problem of undue vibration in the eccentric, it is desirable that the length 'of stroke and the frequency of stroke imparted to the pull rod of one or more of the wells be varied and controlled as the pumping demands change during the life of the well. Provision lot a pendulum at an intermediate point between the eccentric and the well site may be used to efiect a change 2,896,458 Patented July 28, 1959 in the length of stroke to a well but such expedients hav only a limited application.

It is known in the art to use adjustable central power eccentrics which are adapted to change the length of stroke. Similarly, the length of stroke between a central power unit and various belt drives may be changed by the use of transmissions through which the belt drives are connected. Pumping jacks are in existence which utilize a vertical pitman operating from a walking beam which pitman is connected through a pulley to the power source. V

These prior art devices, including variable stroke drives for oscillatory members, do not eliminate the accidental equilibrium condition wherein a pitman may come into dead center in relation to the rotating members of the mechanisms. Also, the action of the pitman is direct and generally only one pitman linkage exists between eccentric or rotating members which brings about considerable wear at the bearing points when the eccentric begins to have a slight erratic motion due to internal stroke to a well pump or similar device.

A further object of the invention is to provide in combination an eccentric, a pitman connectedvthereto, a first pulley connected to the pitman, a second smaller pulley connected to the first pulley, and a second pitman or pull rod operating a Well pump.

Another object is to provide crossed pitmansconnected between an eccentric and a driving pulley.

Still another object is to provide crossed-rigidly fastened pitmans connected between an eccentric and a drive pulley or gear which overcomes vibrations in the movement of the eccentric.

These and further objects of the invention will becom apparent as the description thereof proceeds.

The invention is best illustrated by reference to th attached drawings forming a part of the. specification wherein there is shown at least three embodiments of the invention and in which:

Figure 1 is a plan view looking down on one embodiment of the invention employing a single pitman conneoted between a central power eccentric and a driven pulley. 1 t

Figure 2 is another plan view looking down on another embodiment of the invention employing crossed pitmans which are each attached at one or more points to the eccentric.

Figure 3 is a plan view looking down on an embodiment of the invention employing another arrangement of crossed pitmans.

.The drawings are partially diagrammatic in form intended to show only the essential mechanical elements of the invention and leaving out the auxiliary parts of the apparatus, such as the prime mover, the gear box connected to crank arm carrying the eccentric, the various trunnions and bearings which would be used to support the elements shown.

The invention is best explained by reference to the drawings wherein in Figure 1 the numeral 10 refers to the table of the central power eccentric. Eccentric table 10 is carried on shaft 12 by crank arm 14. Crank arm 14 is affixed to and rotates with shaft 16. Shaft 16 is the driving shaft for eccentric receiving its power from a gear box or transmission located under eccentric 10 but not shown in the drawing. A prime mover, also not Crank arm 14 carried by shaft 16 moves in a circle (shown by the directional arrow) having a radius of the distance between shafts 12 and 16. This motion carries eccentric around shaft 16 carried by shaft 12 so that any of the peripheral points on the table move in a circle equal to the effective radius of arm 14. Attached to the periphery of eccentric 10 are a plurality of'pull. rods 18 carried or attached by bolted collars 20. Each collar 20 is fastened to the eccentric table by'pinions or bolts 22. Pull rods 18 extend to the various pump jacks of the wells being operated. These pull rods may vary in length from several hundred feet to a mile or so. They are carried across the ground by supporting slides or guides which allow the pull rods to move back and forth without too much friction and keep the pull rods in place. This arrangement is commonly referred to as rod lines. Ordinarily the eccentric, its driving mechanism and the prime mover will be located in a building with the various rod lines extending through wall apertures just above ground level. Y

Although a particular arrangement of eccentric table carried by a crank arm is shown, other types of eccentrics may be used and the invention is not to be limited to the specific arrangement shown. Thus, the invention may be used with a circular or eliptical cam drive instead of a crank arm drive.

Figure 1 represents one embodiment of the invention wherein the problem of changing, that is shortening the stroke in a rod line, is accomplished. This also increases the frequency of the strokes and is used as it becomes more and more difficult to remove the oil from a given well or where change in stroke is necessary for other reasons. To accomplish this, one or more of the rod lines 18 is replaced by a pitman 24, pinioned to the eccentric table by pin 26.. Pitman 24 is shown pivotally mounted to the top of eccentric table 10 for purposes of simplicity; The eccentric table 10 may comprise a single flat circular member made 'of steel or wood to which the various collars 20 are pinioned on either top or bottom.

Another arrangement of eccentric table may comprise two parallel separated flat circular tables between which the collars 20 are pinioned. In this latter arrangement.

the-outer peripheral opposed spaced edges of the tables are provided with recesses therebetween so that the collars are free to oscillate as the pinions 22 describe their circular :motion. Pitman 24 may be attached as shown or attached to a collar 20' or carried between two spaced eccentric tables as just described. Figure 1 shows only one pitman 24; however, it is to be understood that each pull rod 18 may be replaced by a pitman 24 as the need arises.

Associated with pitman 24 is shown a pulley 28 connected by a belt 30 to smaller pulley 32. Pitman 24 is carried or attached to pulley 28 by means of pin 34.

Pulleys 28 and 32 are carried on base member 36, which is held in place to a suitable firm foundation by means of bolts 38. Trunnion 40 extends from base 36 and carries shaft 42 upon which pulley 28 rotates. Similarly, trunion 44 carries and supports shaft 46 upon which which pulley 32 rotates. Trunnion 44 may be slidably mounted to slot 48 and made adjustable through the cooperation of screw 50 carried by threaded aperture in wall 52 with its end bearing against the trunnion by means "of plate 54. By this means screw 50 can be retracted within slot 56 to vary the tension on belt 30 or move pulley 32 close enough to pulley 28 whereby the belt or belts can be removed and proper maintenance accomp'lished.

Pulleys 28 and 32 are preferably multiple V-belt drive pulleys and preferably employ notched belts as shown at 58 which do not slip or creep on the pulley. In place of the pulley 28 and 32 and belt 30 a sprocket and chain may be used. Although this arrangement would require suitable protective housing for safety purposes in place of the pulley arrangement, there may also be used .relationship of motion of the parts.

.4. a gear system as will be described in connection with Figure 3. Each of the pinions or shafts will have associated therewith suitable bearings (not shown) either of the ball or roller type.

Pulley 28 will have a radius which is the same as the radius of crank arm 14 and the circle described by pinion 26 holding pitman 24 to eccentric 10 will be of the same diameter as pulley 28. Pulley 32 is preferably one-half the diameter of pulley 28 at the points of attachment. Pulley 32 carries pull rod 60 pinioned at its periphery by pin 62. Directional arrows are included to show the The points of attachment of pitman 24 at pin 34 and pull rod 60 at pin 62 must be as shown in Figure 1 in order that the well stroke of pulley 32 may be utilized to carry pitman 24 past dead centers located approximately at points A and B illustrated on pulley 28, on opposite sides of center shaft 42. Pulley 32 will be undergoing a power stroke as pin 62 passes from point C illustrated thereon to point D, which means that the entire weight of the pull rod 60, the friction in the pump jack, the weight of the polish rod .extendinginto the well and the work required to operate the pump and lift the oil is being overcome.

As pin 62 passes upwardly from point D to point C, pulley 32 will be passing through a well stroke wherein there is a strong pull in the direction of the well. There- .fore, with the position of parts as shown in Figure 1 pitman 24 is under a thrust from eccentric 10 tending to move the pulley 28 in a counterclockwise motion. During this time pulley 32 is under a power stroke and the greatest pull is exerted on pull rod 60. As pin 34 ap proaches point B, the dead center, pin 62 on pulley 32 will be at the top or in the middle of the well stroke, since pulley 32 is one-half the diameter of pulley 28. This will cause pulley 32 under the impetus of the well stroke to pull pin 34 and pitman 24 off of dead center B. Similarly, as pitman 24 is passing from dead center B to dead center A, pull rod 60 will be under a power stroke and as pinion 34 reaches dead center A, pin 62 on pulley 32 will have passed into its well stroke and again will serve to pull pitman 24 off of dead center A.

Referring to Figure 2 a simplified plan view of another ernbodimentof the invention is shown. In Figure 2 the same parts corresponding to those shown in Figure .1 bear the same numerals and the base support members and associated trunnions and adjusting screw have been omitted for simplicity. Eccentric table 10 is connected .to pulley 28 by means of two cross pitmans 70 and 72 by means of bolts or similar .fastenings 74, 76, 78 and 80.

One arrangement comprises the attachment of each of the pitmans 70 and 72 at one point on eccentric table 10. For this purpose, bolts or fastenings 76 and 80 would be used and fastenings 74 and 78 would be omitted.

The opposite ends of pitman 70 and 72 are carried on pulley 28 by means of arm 82 and pins 84 and 86. Ann 82 provides a convenient means for attaching two pitmans to a single point on pulley 28, while still keeping the pitmans in substantially the same horizontal plane. An alternate arrangement would be attached to ends of both pitmans 70 and 72 to a common pinion 88 without the use of arm 82. Pulley 32, which is also one-half the diameter of pulley 28, carries crank arm 90. Crank arm 90 has several apertures 92, 94, 96 and 98 along its length by means of which pull rod 60 may be attached through a pin 62. This provides additional final adjustment of the length of stroke imparted to pull rod 60.

In the embodiment shown in Figure 2 crank arm 14 has rotated 90 counterclockwise from the position shown in Figure 1. This movement has carried pitmans 70 and 72 and pinion 88 to approximately the dead center point on pulley 28. At the same time, pulley 32 and its pin 62 have passed from the middle ofthe power stroke to the middle of the well stroke and again the well stroke serves to carry the pitmans past the dead center. 7

assaass Referring to Figure 3, the same eccentric arrangement is shown as in the previous figure with gear wheels 100 and 102 in place of pulleys 28 and 32. Gear wheels 100 and 102 may be of the sprocket, helical or herringbone type. Gear 100 is carried by shaft 104 and gear 102 is carried by shaft 106. The suitable trunnions and base to support the gear wheels have been omitted for simplicity. Eccentric carries cross pitmans 108 and 110 at pinions 112 and 114 on its periphery. The opposite ends of pitmans 108 and 110 are carried by pins 116 and 118 respectively through arm 120 attached to pinion 122 on the periphery of gear 100. Pitmans 108 and 110 are attached firmly to each other at their point of crossing by means of plate 124 and bolts 126. This arrangement holds the cross pitmans 108 and 110 in rigid relationship to each other.

Crank arm 114 in Figure 3 has rotated 90 from the position shown in Figure 2. Because of the reverse rotation of gear 102 as compared with pulley 32 (Figures 1 and 2), gear 100 and pitmans 108 and 110 are now in the middle of the well stroke and gear 102 is likewise in the well stroke.

Figure 3 also shows an arrangement whereby crank arm 128 is pinioned at shaft 130 to rod 132 whereby the reciprocating end of rod 132 is carried in a straightline motion by sliding member 134 held within fixed guides 136. Pull rod 60 connects directly to sliding member 134. This arrangement prevents the undue vibration of the rod in its carrying members by reciprocating motion of the crank 128. It is contemplated that a similar arrangement may be attached to pull rod 60 and the embodiments shown in Figures 1 and 2. This is omitted for the sake of simplicity in the drawings.

Referring to Figures 2 and 3, it is seen that the cross pitman arrangement shown therein will prevent unevenness or vibration in the motion of eccentric 10. The arrangement shown in Figure 3 has the additional advantage of requiring only one point of attachment of each pitman to the eccentric table 10. In addition, the gear wheels 100 and 102 assure that the pitmans and pull rod do not get out of phase.

The present invention, as seen from the foregoing description, may be used with any type of rod-separated plunger-displacement pumps. Such types of pumps are frequently used in oil well service and need only brief description. Plunger-displacement pumps have a cylindrical working barrel which is suspended from the casing head on a column of tubing so that the barrel is immersed in the well fluid. A plunger or piston located within the working barrel of this plunger is given an up-and-down motion by a column of sucker rods attached thereto which extend up through the tubing to the surface of the well. At the surface of the Well the sucker rods are attached to the polish rod which passes through the casing head and stufling box and attaches to an adjustable grip affixed to the end of a walking beam or other type of pump jack. The walking beam or pump jack is actuated by the rod line coming from the central power eccentric.

There are several types of plunger pumps. One type is the tubing pump in which the working barrel is attached to the lower end of the well tubing and the plunger is suspended on the lower end of the column of the sucker rods. Another type is the so-called rod pumps or insert pumps in which the complete assembly, including the plunger and working barrel, is affixed on a lower end of the column of sucker rods; and, still a third type, called a casing pump, is attached and a rod type of pump is supported by a packer set against the casing. The American Petroleum Institute classifies rod actuate pumps into 5 groups in its API specification for oil well pump (Standard 1lA).

These groups include the tubing with shoe, tubing type with extension shoe and nipple, the rod type with stationary barrel top hold down, the rod type with stationary barrel and bottom hold down and the rod type with '6 traveling barrel. The present invention may be used with any one of these plunger type pumps. Also, the steel plunger pumps adapted to prevent leakage under high hydrostatic pressures, as in the case of deep wells, may be used.

In the drawings only one variable stroke mechanism is shown connecting between the primary driven means (eccentric tables 10) and the second driven means (rods 60 leading to oil well pumps or other mechanisms). It is apparent from the foregoing description of the invention that any number of the variable stroke mechanisms may be attached to a given eccentric table by means of the pitman arangements shown in the individual drawings and that various combinations of these arrangements may be used to replace the direct linkages represented by pull rods 18. Thus, a given eccentric may carry several variable stroke mechanisms as shown in Figure 1 or several mechanisms of the types shown in Figures 2 and 3. Or, a given eccentric may be connected to three (3) different wells by means of each of the variable stroke mechanisms shown in Figures 1, 2 and 3.

Although the invention has been illustrated by specific embodiments, it is to be understood that the only limitations attaching thereto appear in the appended claims.

What is claimed is:

1. A device for translating circular oscillatory motion into reciprocating motion of different magnitude comprising, in combination, eccentric means for providing circular oscillatory motion, a pitman pivotally connected at one end to a point removed from the center of said eccentric means, the other end of said pitman being pivotally connected to a rotatable driven means at a point removed from the center of rotation thereof, said rotatable driven means being connected to a second rotatable driven means having a diameter difiierent from the diameter of said first driven means and means pivotally connected to said second driven means to be reciprocated thereby, whereby the reciprocating motion taken from said second driven means is of a ditferent magnitude than that of said eccentric means.

2. A device in accordance with claim ,1 in which said first driven means and said second driven means comprise a pair of intermeshed gear wheels.

3. A device in accordance with claim 1 in which the diameter of the first driven means is twice that of the second driven means.

4. A device in accordance with claim 1 in which said first and second driven means comprise a pair of beltconnected pulleys.

5. A device in accordance with claim 1 in which the means pivotly mounted to said second driven means comprises a pull rod, same being attached at. its remaining end to a third driven means.

6. A device in accordance with claim 5 in which said third driven means is a well pump.

7. A well pumping device adapted to actuate a rod operated plunger type displacement pump within a well said pump having a power stroke in which the device overcomes the weight of the connecting sucker-rod and the work necessary to lift the liquid being pumped and a well-stroke in which the weight of the sucker-rod tends to return the component parts to a normal position opposed to said power-stroke comprising, in combination, means for imparting circular oscillatory motion to an eccentric table, a first and second driven rotatable means of unequal diameters, means drivably connecting said first and second driven rotatable means, at least one pitman being pivotally connected at the ends thereof to equidistant points from the centers of said eccentric table and said first driven rotatable means, whereby oscillation of said eccentric causes the motion of said pitman to rotate said first driven means, said second. driven means connected by means of a rod line and sucker-rod to said pump, the point of connection of said rod line to said second driven means being such that the well-stroke carries said pitman past the dead centers on said first driven means.

8'. A device in accordance with claim 7 in which two pitmans are connected between said eccentric table and said first driven means, said two pitmans having each end thereof attaching to said eccentric table at two or more rigid points, the other ends of said pitmans connecting to a common point on said first rotating means.

9. A device in accordance with claim 8 in which said pitmans cross each other and their ends are pivotly connected to an arm, said arm being pivotly connected to a point on said first driven means.

10; A well pumping device comprising, in combination, means for imparting circular oscillatory motion to an eccentric table, a pair of belt-connected pulleys, a pitman pivotly connected between a peripheral point on said eccentric table and one of said pulleys the radius of circular oscillatory motion of said table being equal to the distance between the center of said last mentioned pulley and the point of attachment of said pitman, a rod line pivotly attached to said remaining pulley at a distance from the center thereof which is less than the radius of said circular oscillatory motion of said eccentric.

1-1 A device in accordance with claim 10 in which a second pitrnan is pivotally connected to said eccentric table at a point opposite the point of connection of said first pitman, and the other end of said second pitman is connected to the point of connection of said one pitman onsaid first mentioned pulley.

12. A Well pumping device comprising, in combination, means to impart circular oscillatory motion to an eccentric table, a pair of belt-connected pulleys, a pair of crossed pitmans, said crossed pitmans each being connected at diametrically opposite points on the periphery of said eccentric table, the other ends of said crossed pitmans being attached to a common point on one of said pulleys, the other of said pulleys being connected by a reciprocat-able rod-line to a plunger type pumping means,- the radius of said circular oscillatory motion of said table being equal to the distance between the center of said first pulley and the point of attachment of said crossed pitmans and said pulleys being of different diameters.

13. A pumping device comprising, in combination, means to impart circular oscillatory motion to an eccentric table, a first gear wheel having a pin on its periphery, an arm pivotly connected at its center to said pin, a pair of crossed pitmans pivotly connected at one end to each end of saidarm, the other ends of said pitman being pivotly connected to diametrically opposite points on the periphery of said eccentric table so that the oscillatory motion of said eccentric table causes said first gear to rotate under the thrust of said pitmans, a second gear meshed with said first gear the diameter of said second gear being one-half of that of said first gear, a rod line pivotly attached to said first gear, said rod line connected to a plunger type pump within said well.

14. A pumping device in accordance with claim 13 in which said second gear carries a crank arm and said crank arm is connected to said rod line through a connecting rod and sliding means, said sliding means being guided by opposing spaced parallel guides.

References Cited in the file of this patent UNITED STATES PATENTS Arnett Feb. 7, 1871 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No.,,2,896,458 July 28, 1959 Roger B White It is herebjr certified that error appears in the-printed specification of the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 4, line 59, for "attached to" read to attach the column 5, line 17, for "114" read 14 a Signed and sealed this 1st day of March 1960.

( SEAL) Attest:

KARL H. AXJINE ROBERT C. WATSON Attesting O cer Commissioner of Patents

Images