US 1603675 A
Description (OCR text may contain errors)
Oct, 19, 1926. 1,603,675
l R. H. FOLSOM ET AL OIL WELL PUMP Filed J'une 22, 1926 2 Sheets-Sheet 2 INVENToRs F'o/.S om, JWSee/y.
Patented Oct. 19, 1926.
UNITED STATES PATENT OFFICE.
ROBERT H. FOLSOM, F LOS ANGELES, AND JOSEPH W. SHEELEY, 0F SANTA MONICA, CALIFORNIA.
Application led June 22,
The present invent-ion relates to deep Well reciprocating pumps of the type in which a plurality or' telescoping tubes provide a labyrinthine path through which fluid must e travel before it can slip from above the Working valve to points below the Working valve and plunger.
In pumps of this type there always exists an isolated space which increases in volume during one stroke of the pump, and decreases in volume on the other stroke of the pump.
The principal object of our invention is to provide a pump of the class described in which there is provided an annular space l5 which increases in volume during the outward or discharge stroke of the pump, and in which a Vacuum or pressure reduction is created during the out stroke to such an eX- tent that fluid` finding its way into such space will lose its pressure or head, thereby reducing or eliminating the tendency of such fluid to travel farther.
In some pumps of the foregoing type, said annular space is in communication with other large spaces to the extent that a high degree of vacuum, or pressure reduction, cannot be obtained, with the result that even when said annular space has been increased to the maximum there still remains a pressure, due to expanding gas, and also due to oil expanding intova gas; such pressure acting to urge the fluid in said annularspace to travel on into the suction chamber. It is understood of course that the capacity of all plunger pumps .depend upon the amount of fluid which can be drawn through the suction, or standing, valve. Any fluid which slips from above the working valve back to the suction chamber during the out stroke of the plunger, reduces the efficiency of the pump to that extent.
In other pumps of this type, a high degree of vacuum may be created, provided the said space can be sufficiently evacuated during the inward stroke of the plunger, but in all such pumps the channels of escape for fluid during such down stroke are limited in area, with the result that the fluid is under high compression just as the plunger begins vits outward stroke.
Particularly in the case of oil in oil Wells, we have found it not advisable to have the fluid under such compression by reason of the 1926. Serial No. 117,774.
fact that oil under compression, when in the well` is known to almost invariably1 con- 55 tain gas, either in a gaseous or liquefied state, which gas expands upon increase of Volume and prevents the reduction of rapid pressure diminution.
Now, it is one of-the rimary objects of this invention to provide for creating a rapid, or practically initial, pressure diminution in the annular space immediately said space begins to increase in volume.
Our invention contemplates the use of valvular means for driving gas and oil from the annular space during the in stroke of the plunger, 'and therefore, it is another object of this invention to provide valvular means more particularly suited to carry out the aforesaid ob'ects.
Still another o ject of this invention is to provide for removing from the pump jacket or barrel, all working parts without necessity for fishing for same.
Still other objects, which include rugged construction, easy installation and general efficiency, will appear hereinafter.
Another and im ortant object of our invention is to provi e for applying the invention to Worn out pumps, or newly installed pumps of other types, without necessity for pulling the pumpand tubing out of the well; it being not uncommon for the cost of installing a new pump to run as high as the entire sales price of the new pump.
' l/Ve have illustrated by the accompanying drawings two forms of our invention, by way of example only, inasmuch as those skilled in the art will, vfrom the foregoing, 9o easily conceive other modifications and constructions within the scope of our invention.
In the drawings Figure 1 is a view in vertical section of the upper part of the preferred embodiment 96 of our invention.
Figure 2 is a view in vertical section of the lower part of said embodiment.
Figure 3 is a view in Section on a line 3 3 of Fig. 1.
Figure 4 is a View in elevation on smaller scale of the complete plunger assembly of the said embodiment, as it appears when being lowered into a well.
Figure 5 is a View in vertical section of 105 the upper partl of a modified form of pump.
Figure 6 is a cross section on a line 6%6 of Fig. 5.
Figure 7 is a view in vertical section of the upper part of another form of pump constructed in conformity with our invention..
Figure 8 is a view in vertical section vof the upper part of still another form of our invention.
Figure 9 is a vertical section of the upper part of another pump.
In the pump shown in Figs. 1 to 4 inclusive, there is provided an outer plunger tube 15, an inner plunger tube 16, and a standing tube 17. The standing tube is fitted at thel lower end with a blind cage 18, having a transverse wall 19 provided with apertures 20. Centrally of the group of apertures there is provided an inwardly extending projection 21. The cage 18 is threaded, as at 22 to fit over a common standing valve body 23. A common standing valve seat 24 is held between the body 23 and the cage 18, and on said seat there reposes a ball 25. rll`he said ball and seat are known as the standing valve and serve to permitfluid to enter the pump chamber 26 through an inlet passage 27 provided in the standing valve body. Said valve prevents return flow of fluid. The projection 21 acts as a stop for the ball and prevents the ball from obscuring any lof the apertures.
The .standing tube is provided at the upper end with an internal annular enlargement 28 providing a shoulder 29. The outer plunger tube is a working fit over the standing tube and the inner plunger tube, at the v lower end, is a working fit within the standingtube.
An intermediate annular space 30 remains between the inner and outer plunger tubes, respectively, and provides what is hereinafter known as the leakage space. This space of course increases in effective volume as the plunger tubes move upwardly and decreases as they move downwardly. The inner plunger tube is of reduced diameter, as at 3l, to provide a. shoulder 32, which coacts with shoulder 29 in such manner that the standing tube cannot be withdrawn from the plunger tubes. The length of the reduced portion of the inner tube is such as to permit of normal stroke of the plunger without the shoulders abutting each other.l At- 33 a slight clearance is provided between the enlargement of' the standing tube and the reduced part of the inner plunger tube.
rlhe inner plunger tube carries a working or traveling valve 35, comprising a ball 36 and a seat 37. This valve is preferably placed directly at the bottom of the inner plunger tube and as near the standing valve as possible to prevent gas lock, or compression of gas between the said valves.
The inner and outer plunger tubes are Leoswi jointly known as the plunger; said plunger therefore providing the said annular space and the central fluid course 38. The working valve 35 permits huid to flow upwardly into the fluid course 38, but prevents its return back to the standing valve.
rlho two plunger tubes are jointly held by a plunger head 40. The inner plunger tube is attached to a threaded portion 4()EL thereof, and the outer plunger tube is attached to a larger threaded portion 40". The fluid course extends into the head, as at 38, but is terminated therein, as by a solid wall 40. Fluid dischargepassages 41 lead from the fluid .course outwardly through the head to provide for discharge ofy fluid from the fluid course to points externally of the plunger.
lt will be understood that this pump is installed within tubing 42 which rises to the surface to convey the fluid pumped. Said plunger discharges into this tubing through the passage 41. The lower end of the tubing is shown provided with a standing valve shoe 43 into which the standing valve body is wedged tightly. It will be apparent now that as the plunger rises, the working valve holds the fluid, which is above it, in the fluid course; said fluid course being in direct communication with the i11- terior of the oil well tubing 42. At the same time the plunger is drawing fluid through the standing valve. When the plunger moves downwardly the standing valve closes and the working valve opens; fluid now moving relatively up throughv the fluid course and out of the fluid passage 41.
In conformity with a salient feature of our invention, the plunger head is provided with a pocket 45 entirely isolated from the fluid course 28 and provided with a valve seat 46 held in place by the usual valve cage 47, which contains the ball 48. The valve cage is provided with the upper threaded pin 49 to which are attached the usual sucker rods (not shown) by which the pump plunger is reciprocated. From the lower part of the head, at points intermediate of the two plunger tubes, there are provided leakage discharge passages 50, which lead to the pocket 45 and the upper valve 48. ln the construction of the head we provide for the annular space being controlled by a large size non-return valve, and we also provide for the annular space being isolated from direct communication with any other space, except the negligibly small pocket 45, at all times during the up stroke of the pump.- The passages 50 are staggered with regard to the discharge passages 41 and do not connect therewith.
The operation of the inner plunger tube and its coaction with the standing tube to provide pumping action has been explained hereinbefore, and such action is well understood by those skilled in the art. We will tion is created in the annular space.
now describe the manner in which the outer plunger tube, theannular space, and the nonreturn valve 48 coact to provide a so caLled vacuum seal for the inner plunger tu e.
When the plunger moves down, the upper end of the standing tube almost completely fills the annular space and displaces therefrom the corresponding volume of fluid contained therein; which fluid easily leaves by way of the leakage dischar e passages and the nonreturn valve 48. uring the subsequent up stroke of the plunger, the valve 48 of course seats and the annular space becomes fully isolated from the central Huid course and from all other points. During the down stroke any gas. which vhas been contained in the annular space, leaves' readily wit-hout building up back pressure, because of the large area of the valve 48 and the leakage passages. Therefore, when the plunger moves up with the valve 48 closed, a practically instantaneous pressure dimirInie tubes of which the plunger are made are usually steel drawn tubes and are not either machined or ground inside or outside and fit over each other with comparatively large clearances, so that they do not gall, seize or become sanded readily. During the up stroke, oil may slip from the high pressure zone in the tubing, into the annular space, via the clearance between the outer and the standing tube. Unless such slippage is rapid enough to fill the annular space as rapidly as the space increases, there will be no ap reciable pressure in the annular space and t erefore no tendency for oil to slip from there down to the standing valve. Were it not possible to create 'a `partial vacuum'in the annular space` or if said annular space was in communication with a large volume of oil and compressed gas, there would be a greater tendency for oil to be forced from the annular space through the clearance between the inner plunger tube and the standing tube, down to the standing Valve.
In our improved pump the leakage or slip is kept in the annular space under negative pressure until the plunger moves downwardly, whereupon said leakage is pumped back to Where it came from. Therefore, if the annular space is sufficiently large, no fluid raised by the pump will ever slip back to the standing valve and the isolated annular space provides what may be correctly termed a vacuum. seal around the inner plunger tube to preventslippage along said inner plunger tube.
If at any time it is desired to remove all working parts from the well, the lunger is lifted until the shoulders abut. y jerking the plunger against the abutting shoulders, the standing valve body may be disly through said clearance and tends to dis- I courage other fluid from passing downwardly through said clearance; thus an additional iiuid seal which might more correctly be termed an eddy seal. Such eddy seal also acts to retard leakage from finding its way from the annular space to the standing valve during the up stroke of the plunger tubes.
The amount of Huid which may be drawn through the working valve of a pump of this type is generally proportional to the area of the lower end of the inner plunger tube. Usually such amount is only about two thirds of the theoretical volume represented by the area in inches times the stroke in inches. due to various well known causes. Therefore, we consider it preferable to have the parts about the proportion shown in the drawings; the area of the minor portion of the standing tube being about two thirds that of the lower end of the inner plunger tube. For example z-If the area of the plunger tube, is three square inches and the stroke twenty inches, yeach stroke will draw about forty cubic inches of fluid through the standing valve. In such case the area of the standing tube should be two square inches so that the volume increase of the annular space will be forty cubic inches per stroke. The annular space may receive ,fortycubic inches per stroke and the actual suction effect of the pump is only 40 cubicv inches per stroke, therefore, it is obvious that the entire amount of Huid raised by the pump may slip back to the annular space before there is any tendency Ifor such fluid to slip to the standing valve. We have found that common' single tube plunger pumps fail to lift any Huid at all when the slip is equal to the amount of fiuid drawn in. In many oil Wells, pumps are employed which have a capacity of 100 cubic inches per stroke, but forvarious reasons only l0 cubic inches are drawn in at each stroke. If such pump becomes worn `to the extent lthat the slippage is equal to ten percent of the theoretical capacity of the pump, such pump will fail entirely.
In our improved pump, with the above men' tioned proportions, the slip must reach 66 percent of the theoretical capacity before the annular .space can vfill during a single stroke.
In the pump shown in Figs. 5 and 6, we employ a common plunger head 50, having an open fluid course 51 indirect communication with the main fiuid course. In this roviding pump the fluid course rises straight through the plunger. Where the smaller section of the inner plunger tubevjoins the lower larger section of said inner plunger tube, we have provided a coupling or head 53,. having a valve chamber 54 closed by an upwardly opening ball valve 55. From the annular space a passage 56 leads to the chamber 54; while other fluid passages 57 lead through the head without coming into communication with the chamber 54 or the annular space. The action of this form of pump is very similar to the form previously described. When iuid is displaced from the annular space it may readily escape into the uid course, but, during the upstroke of the plunger, the ball 55 seats and isolates the annular space from the main fluid course.
In Fig. 7 we have shown the pump devoid of an inner plunger tube. This form of pump is practically the last described form inverted. rI`he outer tube 58 is the oil Well tubing which leads to the top of the well. The plunger tube is fitted to a common head 59 and the standing tube is inside of the plunger tube. In thls case the annular space Ais at the bottom of the pump and is formed between the tubing 58 and the standing tube.
The standing tube is provided with a coupling or fitting 53 similar to head 53 in Fig. 5. Said tting provides straight passages 60, through which fluid may rise in traversing the main fluid course. It also provides a chamber 541L in communication with the annular space through passages 56a. The
standing valve ball in this case, during the lip-stroke of the plunger, is lifted by the incoming fluid and is held against seat 55*l with such force that lfluid cannot leak from the annular space during the up-stroke. During` the down-stroke of the plun er, the standing ball seats and allows the uid to escape. Whereas, in the form shown in Fig. 5, the ball which isolates the annular space is held closed by the weight of fluid above it, the ball in the last described form of pump is held seated by the incoming fluid.
In the form shown in Fig. 8, we provide a pump head 62, to which both the inner and thel outer tubes are attached, the annular space remaining between the two tubes. Within the fluid course, or within the inner tube, we provide a closed valve pot 63 in which is a valve 64. Nipples 65 connect the valve pot, below'the valve, with the annular space. Other nipples 66 lead from' the valve pot, above4 the ball, through the two tubes, but without communicating with the annular space. In this Jform of pump the fluid pressure external to the plunger 1s exerted through the upper nipples and holds the ball seated during the up-stroke. During the down-stroke fluid may lescape from the annular space by raising the ball from its seat within the valve pot. In this pump the inner plunger tube is of .course provided at the 'lower end with the lower working valve (not shown) as in the case of all other pumps previously described which possess the inner plunger tube. v
In-the pump shown in Fig. 9, the inner tube has an extension 63 internally concentric ofthe outer plunger tube. A head 62 connects the two plunger tubes. In this form the annular space is continued as at 45, by way of parts 50, and terminates at the top of' the extension 63. The cage holds a valve seat 46 in place in such position that a ball 48 may seat on said seat and upon the Vupper end of extension 63, at the same time.
In this form of pump the one ball 48 may serve the joint purpose of preventing fluid 'from returning to the fluid course, while acting also to prevent uid returning to the annular space. During the down stroke of the plunger, this ball becomes unseated and both the annular space and the m'ain fluid course are thereby vented for discharge purposes.
It will be apparent that in all the forms described, the annular space is isolated from any spaces of appreciable volume and is accordingly subject to a high degree of vacuum during the up-'stroke of the plunger, with the result that fluid finding its way into said annular space will remain therein and will not tend to travel farther, until, during the down stroke it is displaced back from whence it came without having reached to the standing valve and without having reduced the suction effect created by the lower end of the inner plunger tube.
We claim :M
l. In a pump, a single` walled member anda double walled member relatively reciprocal and providing an internal central fluid course and an elongated annular space externally coaxial to said fluid course and separated therefrom, a valve body member interposed in said central fluid course and provided with an internal cavity having an outwardly directed opening and further provided with a single annular valve seat in the path ofsaid opening; said seat disposed 'coaXially internally of the pump; said valve body member provided with a through passage providing continuation to said fiuid course and further provided with another passage separated from the first named passage and leading from said annular space to said cavity, an upwardly opening nonreturn valve for said single walled member, and an upwardly opening non-return valve for said double walled member.
2. In a pump, a single walled member and 4a double walled member relatively reciprocal and providing an internal central fluid course and an elongated annular space eX- ternally coaxial to said fluid course and separated therefrom, a valve body member interposed insaid'central fluid course and provided with an internal cavity having anl outwardly directed opening and further provided with a single annular valve seat in the path of said opening; said seat disposed coaxially internally of the pump; said valve body member provided with a through passage providing continuation to said fluid course and further provided with another passage separated from thefirst named passage and leading from said annular space to said cavity, an upwardly opening nonreturn valve for said single walled member, and an upwardly opening non-return valve for said double walled-member; said nonreturn valves and said members arranged to produce suction of fluid into said fluid course during one stroke of such reciprocation, and further arranged so that the annular space is increased in effective volumevduring such suction. Y
3. In a pump plunger for pumps of the class described, a plunger head, a cage fitted to said plunger head, a valve seat between saidcage and said head, a ball within said cage seating on said valve seat, an outer plunger tube depending from said head, an inner plunger tube d e ending from said head; said tubes provi infr a central fluid course within said inner pblunger tube and further providing an annular leakage space intermediate of said tubes, a non-return valve for said fluid course below said head; said head provided with a cavity separated from said fluid course and leading to said valve seat whereby said ball and seat provide non-return control for said cavity; said head provided with a passage leading laterally outwardly from said fluid course,
and further provided with another passage separated from said first named passage and leading from said annular space to said cavity.
4. In a pump plunger for pumps of the class described, a hollow plunger having an inner annular wall providing a central fluid course, a non-return valve in said fluid course, an outer annular wall to said plunger surrounding said inner annular wall in spaced relation to provide an annular space between said walls, with said space open at the bottom and otherwise isolated from said central fluid course; said hollow plunger further provided with a discharge passage leading from said central fluid course outwardly of the plunger above the said nonreturn Valve; said hollow plunger also provided with a central cavity abovesaid fluid course and above said discharge outlet and separated from said fluid course; said plunger further provided with another passage separated from said fluid course and leading from said annular space to said cavity, and a non-return discharge valve for said cavity.
5. A plunger head for pump plungers, which plungers include inner and outer concentric plunger tubes; said plunger head comprising a cylindrical body having an upper coaxial threaded extent for receipt of' a valve seat and valvecage; said cylindrical body also having a threaded portion below said extent for receipt of such outer plunger tube; said body also having another coaxialthreaded portion of smaller diameter than the first mentioned portion for receipt of such inner plunger tube; said head also provided with an internal coaxial cavity opening upwardly and outwardly of said upper extent; said head also provided with a leakage discharge passage leading through said body from the lower end vthereof from a point intermediate of the two threaded portions, thence into said cavity; and said head further providedwith a fluid discharge passage opening at the bottom of said head coaxially ofthe smaller threaded portion and also opening laterally outwardly of the head at a point below said upper threaded extent; said fluid discharge passage being separate from said leakage passage.
6. In a pump of the class described, a hollow plunger provided with an upwardly opening` coaxial cavity at its upper end. an upwardly opening non-return valve above and controlling said cavity; said plunger further provided with a central fluid course extending from the lower end upwardly and opening outwardly of the plunger below said cavity and separated from said cavity, an upwardly opening non-return valve for said fluid course; said plunger provided with an annular coaxial elongated leakage space separated from said fluid course, and said plunger provided with a passage separated from said fluid course and leading from said annular space to said cavit 7. In a pump, a standing tube having the major portion of constant internal and external diameters, respectively, an internal annular enlargement to the upper end of said standing tube, an outer plunger tube fitting reciprocally over said standing tube, an inner plunger tube comprising a'lower extent which is a reciprocal working fit in said standing tube and an upper reduced tubular extent of smaller diameter than the lower extent and being of smaller external diameter than the internal diameter of said internal annular enlargement of the stand ing tube; all, whereby outward movement of said plunger tubes causes that part of the annular space above the standing tube and between the plunger tubes to increase in effective volume while that portion of the annular space intermediate of the said shoulders decreases in effective volume; said annular enlargement causing restricted How of fluid between it and the said upper extent during outward movement of the plunger tubes. l
8. In a pump having inner and outer plunger tubes, respectively, and a standing tube fitted between said plunger tubes whereby outward movement of said plunger tubes causes an increase in effective volume of the annular space between said tubes, means normally preventing totalA withdrawal of said standing tube from said plunger tubes; said means comprising shoulders; one on said standing tube and one on one of said plunger tubes; said shoulders arranged to increase the pressure of fluid existing between said shoulders while the annular space is increasing in volume by reason of outward movement of said plunger tubes with regard to said standing tube.
9. In a pump plunger for pumps of the class described, a plunger head, spaced coaxial tubes attached to said head and providing an annular spaceI between the tubes and a central fluid course; said head provided with outlet ports leading from the interior of the innermost tube, a cavity above said fluid course isolated from said fluid course, and said head further provided with ports'leading from the annular space to said cavity; said ports'entirely isolated from said Huid course, a non-return discharge valve` in said iuid course and a non-return discharge valve for said cavity.
10. In a plunger for pumps of the class described, a double walled plunger providing a central fluid course and an annular space between the walls of the plunger, a pair of longitudinally spaced non-return valves internally coaxial of said plunger; said plunger provided with discharge ports for said fluid course located between the valves, means isolating the upper valve from the lower valve, and said plunger providing a leakage discharge passage leading from said annular space to the upper non-return valve; said leakage discharge passage being entirely isolated from said fluid course.
11. In a pump, a standing valve, a standing tube rising from said standing valve,
an outer plunger tube fitted Itelescopically over said standing tube, an inner plunger tube fitted telescopically within said standing tube, an internal shoulder to said standing tube above said inner plunger tube, an upper inner plunger tube extension of smaller diameter attached to said inner plunger tube and forming a continuation therefor, a plunger head above said standing tube and connecting said outer plunger tube and said inner plunger tube extension; said head provided with a laterally directed discharge port leading from the interior of said inner plunger tube extension to points externally of the head; said head provided with a coaxial valve cavity above said discharge passage and isolated therefrom; and said head further provided with a leakage discharge passage leading from points between the said outer tube and the said inner plunger tube extension to said coaxial valve cavity; said head adapted to hold a valve and valve cage above said cavity, and said inner plunger tube provided with means for retaining a non-return discharge valve.
12. In a pump, a removable standing valve body, a standing tube attached to said valve body and rising therefrom, an inner plunger tube shorter than said standing tube and fitting telescopically therein; said standing tube provided with inwardly directed means adjacent its upper end to normally prevent withdrawal of said inner plunger tube from said standing tube, an inner plunger tube extension attached to said inner plunger tube and rising therefrom externally to and above said standing tube, a plunger head attached to said inner plunger tube extension, an outer plunger tube depending rom said head and fitting telescopically over said standing tube, and nonreturn means for venting the interior of said inner plunger tube and the space remaining between said outer plunger tube and said inner plunger tube, respectively.
ROBERT H. FOLSOM. JOSEPH W. SHEELEY.