US2161922A - Hydraulic pump jack or head - Google Patents

Description

June 13, 1939.

R. B. GOODE HYDRAULIC PUMP JACK OR HEAD Filed April l5, 1936 ---in .n.luur/ l: r4,

Patented June 13, 1939 UNITED STATES PATENT OFFICE Application April 15,

4 Claims.

This invention relates to improvements in well pumps, and its objects are follow:

First, to provide a hydraulically operated pump jack head or motor for deep wells, which head is constructed for an exceptionally long stroke, use being made of the conventional casing head for the support of the motor when the major length of its cylinder is projected into the well casing wherein it is designed to ordinarily remain.

Second, to embody such a construction in the motor as will enable the removal of the entire inner working assemblage by merely taking oli the upper cylinder head, thereupon inserting and attaching a pull rod to the piston rod, the removal of said assemblage leaving an unobstructed passage into the well tubing.

Third, to provide the piston with a valve the -stem of which has tapered iiutes which throttle the flow of liquid through the piston and thus cushion its arrival at the end of the down stroke.

Fourth, to provide the top anvil with a spring which, upon reacting to compression at the end of the upstroke of the piston, aids in cracking the valve from its seat in the piston.

Fifth, to provide for variation in the length of the piston stroke by adding a downward extension to the upper cylinder head to intercept and open the valve, earlier than in an otherwise full stroke.

Sixth, to use the pump cylinder as a carrier for the bottom coupling from which the tubing string is suspended, said coupling also being the outlet for the oil lifted in said string.

Other objects and advantages will appear in the following specication, reference being had to the accompanying drawing, in which:

Figure l is a vertical section of the improved pump jack, -parts being shown in elevation.

Figure 2 is a detail section of the lower end of the motor, illustrating the throttling action of the valve on the liquid as the piston approaches the end of the down stroke.

Figure 3 is a cross section taken on the line 3 3 of Fig. 2.

Figure 4 is a cross section taken on the line 4-4 of Fig. 2.

Figure 5 is a fractional sectional View of the upper end of the pump jack illustrating a modification whereby the length of the piston stroke can be varied.

It is a well established practice in many oil iields to use pump jacks in connection with Wells that have to be pumped. Without going into detail as to the construction and operation of the ordinary mechanical pump jack, each of 1936, Serial No. '14,563

which is commonly known, it is sufficient to state here that at best the stroke is very limited with the result that the limited production has to be compensated for by longer periods of operation than would be necessary if more oil could 5 be lifted with each stroke.

It is with the latter purpose in mind that the instant pump jack has been devised. It is operated on established hydraulic principles, and one of its features is to make possible an exceptionally long stroke with each operation so that more oil can be lifted with each stroke than possible with the ordinary pump jack, and with 'less wear and tear on the mechanism.

Attention is directed to the drawing. The 15 upper cylinder head I is screwed at 2 into a T 3 which has a lateral outlet 4' into which the low pressure liquid return pipe 5 is secured. This pipe discharges into a reservoir 6 of any desired type. This reservoir supplies liquid to a pump 1, also of any desired type, from which liquid at high pressure is delivered through a pipe 8.

The T 3 is screwed on to the upper end 9 of the cylinder or barrel I0 of the motor generally designated II. It is this motor that constitutes the invention, also the combination of the motor with the well casing which is established in this way.

A boss I2 on the cylinder I0 is made large and heavy enough to be rested upon and secured to the casing head generally designated I3. This head is of the conventional type and it forms part of the casing I4 which extends below the earth surface into the bore of the well. The cylinder I0 is exceptionally long, and because of its length, 35 is projected into the casing I4 until the boss I2 comes to rest on the casing head I3, as already stated. Most of the hydraulic motor is thus out of the way, and the conventional casing head I3 is brought into combination with the motor as 40 a foundation.

Chambers I5 and I6 in the boss l2 are respectively in communication with the pipe 8 and with an offtake pipe I'I. It is through the latter that oil or other liquid produced by the well and lifted by the pump jack is conducted to a storage tank (not shown). At its lower end the cylinder I has an internal enlargement I8 which provides the support for the lower cylinder head I9. This head is merely slipped into position (Fig. 2). It 50 is not secured because there is enough pressure above it to hold it down. Moreover, it is intended to lift this head out of the motor cylinder I0 as part of the internal working assemblage when the necessity arises to remove the latter.

A circular flange 20 upstanding from the lower cylinder head |9 is threaded on the outside and inside at 2|, 22 to take rings 23, 24 which, when screwed home, clamp external and internal cup washers 25, 26 in place. 'I'he lilst provides a liquid-tight joint against the bore of the cylinder l0, the other a similar joint against the surface of a piston rod 21. Y

'Ihis piston rod extends from inside the motor down into the well tubing 28 (Fig. -1). 'Ihe piston rod may comprise one piece, or it may com'- prise a plurality of pieces coupled as at 29. Whether made of one or more pieces, it is provided with a projection 30, here shown in the nature 'of a collar. below the lower cylinder head 9 so that when the piston rod 21 is lifted for the purpose of removing the internal assemblage it'will engage the lower cylinder head to partly accomplish the purpose. The projection 30 is far enough below the lower cylinder head as notrto engage it in the `ordinary pumping operation. The sucker rod string 3| is' coupled to the piston 21Y at 32 below the projection 30.

'Y cylinder |0 as at 34.

A tting 33, herein known as the bottom coupling, is secured to thev lower end of Ythe motor This coupling is hollow. Thefwell tubing 28 is screwed into it and the coupling receives the oil as it is lifted fromthe Vwell tubing 28 by the pump plunger (not shown) atV the bottom of theY sucker rod string 3|. A bypass pipe 35 is lsecured at its ends to the boss l2 and bottom coupling 33 to communicate with the respective chamber I6 and interior of the bottom coupling, to conduct Vthe oil from the latter to the former, thence off to the tank byway of the pipe` I1. l

` The motor piston is `generally designated 36. It includes the lower part 31 anda head 3.8. vWhen the two are screwed down upon the threaded upper end 39 ofthe piston rod theyv clamp Va Vcup washer 40 between them. A valve bore 4| extends through -the piston36 from the top to Y the bottom surface, the bore being enlarged at toV the Vlatter to provide a seat42.

n A valve 43 isa'dapted to engage the seat 42. When it does it closes off Ycommunication between vthe upper and lower ends of the cylinder above and below the piston 36. YThe valve43 has a long stem made in two diameters; The thick part 44 occupies and slides in the bore 4|. The thin part 45 carries supports 46 for the upper ends of a pair of springs 41, the lower ends of which are anchored to hooks 48 (or their equivalents) set in the piston head 38.

In order that the piston 36 will be cushioned upon its arrival at the end of the down stroke (Fig. 2), the thick part V44 of the valve stem is provided with downwardly tapering flutes 49, the function of whichV is to throttle the ow of liquid through the piston 36 and thus slow and eventually stop the piston. The lower and small terminals of, the flutes 49 stop short of the inner Vperiphery'of the valve 43 as indicated at 50. This Y Y' about by the engagement of a pilot 5|, pendentY 7o from the valve 43, with the lower anvil or abutment 52. This anvil isV supported by a heavy spring 53 which rests upon the lower vcylinder head |9. 'Ihe provision of the pilot 5| is only one way of preventing the closure of the pressure-liquid intake port 54 by the Vpiston 36. This This projection is located engagement, and in the instance of Fig. 1 theY remote ends of the spring are secured by welding or otherwise, to the respective upper cylinder head and anvil 51. The anvil and spring are thus pendent from the upper cylinder head.

In the modication in Fig. the spring 59a performs the same function mentioned, but instead of its being pendent from the cylinder head' la it is secured only to the anvil 51a (or merely rested thereupon), and said anvil is permanently s supported by the stem-45a of the valve 43a, so that the weight of the anvil 51a and spring 599 will aid the springs 41a in holding the valve .13a open. This opening occurs when the upper anvil and spring are raised far enough upon the upstroke of the piston 36a to engage thel spring with a downward extensionV 60 from the cylinder head la. v

This downward extension provides a means for varying the length of the stroke of the piston 36a. In actual practice, provision can either be made for lengthening or shortening the extension 60,

or a pluralityof cylinder heads |a can be pro-V vided with extensions 60 of various lengths. is easy torunderstand thatif the cracking of `the valve 43a from its seat depends Vupon vthe engagement of the spring'5llEl with the/extension 56 in order to initiate the opening of said valve,.

then said function will occur earlier in the return stroke Vof the piston 36a if the extensionV vide a passageway for the liquid to the returnY pipe 5a. v

The operation is vreadily understood. Consider the pump 1 as being in operation, drawing on the reservoir 6 for low pressure liquid and discharging said liquid into the pump jack system under high pressure by Way of the pipe 8. At this point it is to be noted that the pressure-liquid moves in a closed cycle. Trace this from the reservoir 6 throughV the pump 1, pipes 8 and 56, port 54, cylinder I0 and pipe 5 back to reservoir 6. This liquid is not mixed with any that come-s from the well. Nor are any of the internal motor parts exposed to the liquid that comes from the well. Such liquid is often contaminated by salt water and by thus guarding the Working parts of the motor they are kept from corroding, and are also prevented from being worn by sand.

Now to go back to the pump 1; as long as the valve 43 is closed there cannot be any passage through of liquid in the valve bore 4|. Consequently pressure will build up beneath the piston 36, and said piston will be raised in the cylinder I0. This raises the sucker rod string.

Consider the valve 43 closed as just pointed out.

When the long valve stem'strikes the upper anvilV from its seat 42 partly by the impact and partly by the reaction of the spring 59. A full opening of the valve results before the piston 36 ends its upstroke, and the upstroke is ended when the pressure-liquid can pass through the piston and return to the reservoir as indicated by arrows a.

It is now that the piston makes its return stroke solely by weight of the sucker rod string. The pump l continues its operation, but until the piston 36 nears the bottom of its stroke there is simply an idle circulation through the bore 4I. The engagement of the pilot 5I (Fig. 2) with the lower anvil 52 starts the closure of the valve 43. As the tapered flutes 49 are projected into the bore 4l the flow of liquid is gradually throttled. The result is a slowing down of the piston 36, and the eventual stopping thereof when the valve 43 is fully seated. The pressure from the pump 'i builds up once more and raises the piston 36 for a repetition of the cycle thus described.

Respecting Figure 5, the same operation will be carried out, the exception here is that the upper anvil 5la and the spring 59a go up and down With the piston 36, the cracking of the valve not occurring until the spring strikes the extension 60. Upon desiring to remove the entire inner Working assemblage consisting of the piston 36, the piston rod 21 and the sucker rod string and its plunger at the bottom, it is only necessary to take off the upper cylinder head l and attach a suitable pull rod. For this purpose the threaded end of the piston rod projects above the head 38. The pull rod is coupled on here and when said rod is elevated the whole assemblage comes with it.

Another feature on which emphasis is desired to be laid is the use of the motor l I as the suspension for the tubing string 28. The motor cylinder I0 and the tubing string are connected in tandem by the bottom coupling 33, and when the motor is rested on the casing head i3, the tubing string becomes supported at the same time, the coupling 33 obviating the necessity of further supporting means for the tubing string.

I'claim:

l. A motor which has a cylinder, an inner working assemblage consisting of a piston in the cylinder, having a piston rod extending downwardly, means on the piston to enable the removal of said piston, upper and lower cylinder heads, the upper head being removable, the lower head being loosely seated in the bottom of the cylinder, and a projection of the piston rod below the lower head engageable with said head to pull it out with the assemblage when said piston is removed.

2. A motor comprising an upright cylinder having openings approximately at its remote ends, pressure-liquid circulating means connected with said openings so that when said means is worked liquid under pressure is introduced at one of the openings, cylinder heads for the respective ends, a piston reciprocable in the cylinder and having a rod extending through one of the heads, cushion means located between the opposite sides of the piston and the respective heads, a valve contained by the piston having projections above and below its opposite sides to coact with the cushion means at the approximate ends of the downward and upward strokes of the piston, first, to close the valve and enable the liquid entering the lower opening to build up pressure, second, to open the valve and let the pressure-liquid escape through the upper opening, and means combined with said valve to throttle the flow of liquid through the piston as it nears the end of its downward stroke so as to diminish the speed 0f the piston.

3. A motor comprising a cylinder, a piston operable in the cylinder having a valve bore terminating in a seat, a rod extending from the piston, abuttable means at the ends of the cylinder through one of which the rod extends, means to circulate liquid in one direction from end to end of the cylinder, a Valve having a stem occupying the bore, said stem having at least one flute tapering toward the valve but stopping short of the inner periphery of the valve, and projections respectively from the valve and from the stem below and above the piston to alternately engage the abuttable means for closing and opening the valve, the taper of'said ute progressively diminishing the liquid ilow through the bore when the piston nears the end of its down stroke up to the instant of nal closure of the valve.

4. A motor comprising a cylinder, a piston operable in the cylinder having a valve bore terminating in a seat, a rod extending from the piston, abuttable means at the ends of the cylinder through one of which the rod extends, means to circulate liquid in one direction from end to end of the cylinder, a valve having a stem occupying the bore, said stem= having at least one flute tapering toward the valve but stopping short of the inner periphery of the valve, projections respectively frorn the valve and from the stem below and above the piston to alternately engage the abuttable means for closing and opening the valve, the taper of said flute progressively diminishing the liquid flow through the bore when the piston nears the end of its down stroke up to the instant of nal closure of the valve, and means to exert pressure on the Valve so as to hold it open after it has been cracked from its seat by the upper abuttable means.

RONALD B. GOODE.

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