US2291499A - Balancing device for pumping units - Google Patents

Description

July 28, 1942. K. T. PENICK 2,291,499

BALANCING DEVICE FOR PUMPING UNITS Filed May '26, 1939 :5 Sheets-Sheet '1 [leer 7. PEN/CK V HM v a z July 28,1942.' -K. T. PENIYCK I 2,291,499

BALANCING DEVICE FOR PUMPING UNITS Filed May 26, 1939 3 Sheets-Sheet 2 bear 7. PEN/CK July 28, 1942.

K. T. PENICK BALANCING DEVICE FOR PUMPING UNITS 3 Sheets-Sheet 3 Filed May 26, 1939 hear I PEN/CK Patented July 28, 1942 UNITED STATES PATENT OFFICE namncmo maxim rpm-mo Um'rs Kirby '1. lenick, Houston, Tex.

Application May 26, 1939, Serial No. 275,925 2 Claims. (Cl. 74-41) This invention relates to a balancing device for pumping units.

The invention herein described is applicable topumping units embodying counterbalancing weights, or employing fluid under pressure for counterbalancing the weight of the pump rods.

At the present time the usual deep well pump is commonly operated by a string of pump rods, or sucker rods, connected at the upper end to one end of a walking beam mounted to reciprocate on a Samson post. The other end of the beam is connected by a connecting rod, to the crank arm of the transmission of the power unit which is driven by any selected type of motor and whereby the beam is rocked on said post. Upon upstroke of the pump the load to be lifted by the motor comprises not only the column of liquid in the pump tubing but also the string of rods, while upon downstroke the string of rods move downwardly under the influence of gravity thus relieving the motor, either partially or entirely,

during the downstroke of the rods.

do not completely and at all times equalize the load on the motor throughout a cycle of pump movement. As an illustration it may be assumed that the load to be lifted on upstroke is twenty thousand pounds, ten thousand pounds of which is the liquid column and the balance the weight of the rods. Now in order to exactly balance this load the counterweights would have to be twenty thousand pounds in weight. The motor, therefore, upon upstroke, would only be required to add suflicient power to the counterweights to overbalance the load, but on downstroke, or gravity stroke, of the rods said rods would balance only one-half of the weight of the counterwelghts and the other one-half, or ten thousand pounds, would have to be lifted by the motor. The same illustration will hold good when a pneumatic, or

fluid pressure counterbalance is employed.

Therefore, in actual practice the weight of the ing effect of the pressure fluid, is so regulated, or proportioned to the load to be lifted, that it will overcome, a part of the weight of the pump rods and the column of liquid to be elevated; so that upon upstroke the motor will be required to lift only a portion of the total load to be elevated, the. counterweights, or the pressure fluid lifting the balance of the load. Upon downstroke however the rods will be so counterbalanced that there will be little work for the motor to do. By nicely adjusting the weight of the counterweights, or the counterbalancing effect of the fluid under pressure, to the load to be lifted slightly more uniform work may be imposed on the motor, throughout a cycle of pump operation; but with pumping equipment now in use such motor load cannot be made uniform throughout a cycle of pump movement. The motor therefore runs under varying loads, this causing vibration, and requiring a motor of a capacity greater than would be necessary if the load to be lifted were at all times exactly counterbalanced.

With the invention herein described the load on the motor may be exactly balanced, or made uniform throughout the cycle of pump operation, that is, during the upstroke "as well as the downstroke of the pump. This will conduce to the smooth running of the motor and unit andrequire a motor of much less capacity.

It is another object of the invention to provide means of the character described that may be easily adjusted from time to time so asflto maintain the load on the motor uniform, or accurately balanced.

Another object of the invention is to provide an attachment of the character described which is of very simple construction, may be cheaply produced and readily applied tothe various types of counterbalanced pumping units now commonly used.

With the above and other objects in view the invention has particular relation to certain novel features of construction, operation and arrangement of parts, an example of which is given in 7 this specification and illustrated in the accompanying drawings, wherein:

Figure 1 shows aside elevation of a pumping unit illustrating the improvement.

Figure 2 shows a side elevation illustrating the invention as applied to another type of pumpins unit.

Figure 3 shows a longitudinal sectional view of the balancing device.

Figure 4 shows an enlarged longitudinal seccounterbalancing weights, or the cou'nterbalanctional view of the adjusting valve employed.

came mam.

Figure 6 shows an end view of the plunger.

Referring now more particularly to the drawings, wherein like numerals of reference designate the same parts in each of the figures, the numeral I designates a walking beam mounted to pivot, on a horizontal axis, on the Samson post 2. On one end of the walking beamthere is the head 3 whose forward end is curved and about which the cable 4 operates as the walking beam oscillates. The upper end of this cable is attached to the head and its lower end is con-' nected to the upper end of the sucker rod 6 of the well pump. A connecting rod 6 is connected at its upper end to the other end of thewalking beam and at its lower end it is connected to the crank arm I of the transmission 8. The transmission is driven from a suitable motor 9 in any preferred manner as by belting, or a sprocket chain within the housing ID. The walking beam is thereby oscillated as the crank arm I revolves.

In Figure 1 there is illustrated a pumping unit embodying means for counter-balancing the load by fluid pressure, said fluid pressure counterbalancing means being fully described in the copending application of this applicant filed in the United States Patent Ofllce on June 14, 1938, under Serial No. 213,561, now Patent No. 2,233,029 which it is not deemed necessary to describe in detail. However, it embodies the Samson post 2 which is tubular in form and forms a reservoir for compressed fluid and also embodies a cylinder II, with a piston therein, connected to thepiston rod 12. As shown, the piston rod I2 is connected to the walking beam between the Samson post and the connecting rod or pitman 6. For the purpose of forming this connection, a cap I3 is fastened to the upper end of the piston rod 12. This cap has laterally extending trunnions l4, on which the cable sockets 15 are pivotally mounted to which the free ends of the cable loop l6 are attached, said cable working over the curved surface of the head H which is secured in any suitable manner to the walking beam. The construction is such that upon downstroke of the sucker rod, fluid will be compressed to counter-balance the down-stroke and on the up-stroke of the sucker rod, this compressed fluid will be utilized also for counter-balancing the load, all as more particularly described in said pending application hereinabove referred to.

In the form of pumping unit shown in Figure 2, adjustable weights as l8 are mounted on the crank arm i. These weights are so adjusted that upon upstroke of the pump rods they will assist the motor in lifting the pump rods and load but on down stroke of the pump rods they will counterbalance the pump rods so as to partially overcome the influence of gravity to prevent the sudden downward movement of the ,pump rods and the sudden relief of the load Figure isliowsanenlarged-longinidinahaece aboveihg weightsrshown in 'l 'igure; 2, however, while to a certain extent equalizing the load on the motor throughout the cycle or pump operationdo not maintain the load exactly balanced .and additional means, for that purpose, have been devised which constitute the subject matter of the present application and which will be now more specifically described:

The numeral l8 designates a cylinder which is mounted to pivot on the base of the unit. The lower end of this cylinder is closed and secured on the upper end thereof there is a bonnet l8. Within the cylinder l8 there is a piston 20 which is attached to the piston rod 2| whose upper end is pivotally connected to the walking beam. This piston rod 2| works through a stuffing box in the bonnet l9 which forms a seal around said rod. There is a by-pass pipe 23 one end of which is connected into the lower end of the cylinder and the other end of which is connectedinto the valve casing 24. This casing terminates, at i':s inner end, in a choke nipple 25 having a reduced axial passageway 26 therethrough and said nipple is screwed into the outlet passageway 21 leading outwardly through said bonnet.

The inner end of the passageway 26 is controlled by a needle valve 28 which is fixed on the inner end of the valve stem 29 located within the housing 24. Screwed into the outer end of the casing 24 there is an adjusting rod 30 fixed onto the outer end of which there is a hand grip 3| by means of which said adjusting rod may be turned. The inner end of the rod 30 has a deep socket 32 into which the outer end of the stem 29 extends. Surrounding the stem 29, within said casing, there is a strong coil spring 33 whose inner end abuts the annular stop 35 on said stem and whose outer end abuts the annular disc 36 through which the stem 29 slides and which abuts the inner end of the adjusting rod 30. The spring 33 normally holds the valve 28 in position to close the passageway 26 and the compression on the spring 33 may be regulated by adjusting the rod 30. The outer end of the rod 30 is surrounded by a stuffing box 300. which is contained within the valve casing 28 and forms a seal about said rod.

The piston 20 has the fluid passageways 31 therethrough whose upper ends are normally closed by the disc-like valve 38. Rods as 39 are attached, at one end, to the valve 38 and work through aligned bearings in the piston, as shown in Figure 5, and on their other ends are the nuts 40. Surrounding said rods between the nuts 40 and the piston are the coil springs as 4| which normally hold the valve 38 closed.

Upon upstroke of the pump rods when the maximum load is being lifted by the motor the piston-20 will move downwardly in the cylinder iii, the valve 38 will open to prevent resistance of the fluid in the cylinder against the piston 20. This fluid may be a liquid such as oil, or air or the like, under pressure. Upon downstroke of the pump rods the valve 38 will be closed and the fluid above the piston 20 will be forced past the valve 28 and returned through the pipe 23 into the lower end of the cylinder. This resistance may be regulated by regulating the compression on the spring 33 so that the resistance of the fluid in the cylinder above the piston 20 plus the weight of the pump rods, on downstroke will offer the same load on the motor as the weight of the pump rods and the column of liquid upon upstroke to the end that the load on the motor will be balanced, that is, will be exactly the same on downstroke as it is on upstroke of the pump.

The air compression in the cylinder ll of Figure 1 or the counterweights' l8 of Figure 2 may be so regulated as to balance the load, consisting of the pump rods and the liquid column. Therefore, in order to lift this load very little work will be required of the motor and upon downstroke of the pump rods the motor will be relieved of the load of the fluid column but will assume the additional load offered by the resistance of the fluid in the cylinder I8 to the upward movement of the piston 20 and this will be exactly regulated to equal the load of the fluid column so that the motor will be required to do exactly the same work on upstroke as on downstroke of the pump rods.

The motor will therefore run smoother and with less vibration and may accordingly be of minimum capacity.

What I claim is:

1. A pumping unit having a pivotally mounted walking beam connected to the rod of a deep well pump and power means connected to the beam for oscillating the beam to alternately elevate the rod and a column of well liquid and to allow the rod to descend, said unit also having means to counterbalance the load on the beam, said counter-balancing means comprising a tubular Samson post on which the beam is mounted and which contains a reservoir for compressed liquid, a cylinder connected into the reservoir and having a piston therein and a piston rod connected to the piston and also connected to the walking beam between the Samson post and the power means; additional means including a cylinder and a valved piston therein connected to the beam and arranged to entrap a counter-balancing fluid in said last mentioned cylinder upon downward movement of the pump rod and to operate idly upon upward movement of the rod and liquid column being elevated by the pump.

2. A pumping unit comprising a walking beam,"

power means connected to the beam for oscillating the same, a tubular Samson post on which the beam .is mounted, said post containing a reservoir for compressed fluid, a cylinder connected into the reservoir, 2. piston in the cylinder,

a piston rod connected to the piston and also ing connected one to the walking beam between the power means and piston rod and the other to a stationary anchor, a valve casing connected into the second cylinder on one side of its piston, a conduit leading from said casing'and connected into the second cylinder on the other side of its piston, said valve-controlled passageway allowing the free passage of fluid to one side 0! said piston upon movement of said piston in one direc tion and trapping the fluid on said side oithe piston upon movement of the piston in the other direction whereby the trapped fluid will be forced through the conduit into the cylinder on the other side of the piston, a valve in the casing, a yieldablemember acting against the valve and effective to cause the valve to resist the flow of fluid through the conduit, a valve stem on the valve within the casing, an adjusting rod threaded into the casing and having a hand grip thereon accessible to the operator for adjusting the rod, the inner end of the rod being provided with a central socket into which the outer end of the stem extends, said rod being effective by its adjustments to vary the resistance of said yieldable member against the valve.

KIRIBY T. PENICK.

Images