US2061060A - Nonsanding pump - Google Patents

Description

A TToR/VE af.

A. E. CARLSON NONSANDING PUMP Nov. 17, 1936.

Filed Oct. 18, 1932 Patented Nov. 17, 1936 UNITED STATES PATENT OFFICE 1 Claim.

My invention relates to deep well pumps of reciprocating type such as extensively employed in oil and water wells. The invention has its principal utility in pumps employed to pump oil from deep wells.v

Pumps ofithe character to which the invention relates employ a cylindrical barrel and a reciprocating plunger or piston. The piston is also of cylindrical construction andr has sealing V means on the exterior thereof for sliding engagement with the inner face of the pump barrel. In some pumps the external sealing means of the pump piston consists merely of a metal wall of .a size to closely iit the barrel; whereas, in other pumps the external sealing means of the piston is formed by use of annular bodies of ilexible or adjustable material, such as represented by cup washers. Although my invention applies to both of the above set forth general types of pumps, it is of especial utility in pumps employing cup washers as the external sliding sealing means of the piston or plunger. Owing to the expansibility of the cup washers, pumps of this type are very satisfactory where the fluid pumped is relatively free from sand or other abrasive or solid materials; but Where the uid pumped, such as oil, contains sand or other solids, such solids will accumulate behind and above the cup washers so as to force the cup washers outwardly against the pump barrel with such pressure that either the cup leathers are rapidly worn away or the pump plunger becomes frozen in the barrel, with the result of breakage of the string of sucker rods and the necessity of removal of the pump from the well. In sleeve-type pumps employing solid pistons the accumulation of sand between the walls of the piston and of the barrel produces rapid wear and sometimes results in sticking of the pump barrel. This wear of the barrel and the piston rapidly reduces the pumping eiciency due to leakage of oil around the piston.

My invention comprehends a pump piston of cylindrical or tubular form having sealing means on the exterior thereof adapted for sliding engagement with the pump barrel, in conjunction with check valves, preferably of the ball type, disposed at or near-thc upper and lower ends of the piston to prevent a reverse ow of fluid through the axial passage formed through the piston, and openings through the tubular wall of the piston providing communication between the interior and the exterior of the piston for lubricating the intermediate portions of the external face of the piston and for removing the (Cl. 10S-225) sand which tends to accumulate on the exterior of the piston.

Since I believe my invention to have its greatest utility with a pump structure employing cup leathers as the external piston sealing means, I shall hereinafter disclose and describe a simple form of the invention in which the tubular piston has a plurality of cup leathers mounted thereon to serve as sealing means in sliding engagement with the pump barrel, and openings through the tubular wall of the pump piston adjacent the inner faces of the cup washers so that sand which tends to accumulate in the annular spaces formed within the cup washers may be Washed into the interior of the pump piston during the return or down stroke thereof.

Further objects and advantages of the invention will be made evident throughout the following part of the specification.

Referring to the drawing, which is for illustrative purposes only,

Fig. 1 is a sectional view showing an embodiment of my invention in use in a deep well pump having a removable barrel.

Fig. 2 is an enlarged fragmentary cross section of the upper end of the piston disclosed in Fig. 1.

Fig. 3 is a cross section on a plane represented by the line 3-3 of Fig. 2.

Fig. 4 is al cross sectional view similar to Fig.

2, showing an alternative means for securing the parts of the pump piston together in operative relation.

, Fig. 5 is a fragmentary cross sectional view showing the manner in which the external sealing means may consist of a number of cup leathers in superimposed relation.

In Fig. l of the drawing I show the lower end of a vertical tubing or pipe I I extending down into a well, such as an oil tubing commonly used to support a pump in operating position. By means of a tting I2, a pump receiver I3 is secured to the lower end of the tubing II, this pump receiver I3 consisting of a pipe I4 having a seat I5 at its lower end. In the pump receiver I3 is a pump barrel I6 having a valve iltting I1 at its lower end engaging the seat I5 and being provided with a ball I8 to form a foot valve for the pump. The upper end of the barrel I6 is provided with a fitting 20 which carries a conical packing member 2| adapted to engage a conical face 22 of the fitting I2 so as to seal between the upper end of the pump barrel I6 and the upper end of the pump receiver I3. The iitting 20 at the upper end of the barrel I6 provides an inwardly extending shoulder 23.

Within the barrel I6, the lower end of a sucker rod string 25 extends and is secured to the upper end of my new pump piston or plunger 26 which has external sealing means 21 thereon for sliding engagement with the inner face of the barrel I6. The sealing means 21 are preferably in the form of cup washers or cup leathers each, as shown in Fig. 2, having a cylindrical wall 28 for engaging the barrel I6 and an inwardly turned radial flange 3II by which the cup washers are secured to the pump piston 26 between shoulders of cooperating parts of the piston which are adapted to be secured together in consecutive order. As best shown in Fig. 2, the upper end of the piston 26 consists of an annular wall 3| adapted to be secured to the lower end of a tube 32 which forms the upper portion of the plunger and extends from the upper end of the barrel. On the upper end of the tube 32 is a yoke member 33 through which the oil may pass into the oil tube II, having a threaded box 33a by which it is connected to the lower end of the string of sucker rods 25. The lower end of the member 3| is turned down so as to provide a tubular extension 34 projecting downwardly from a radial shoulder 35 and being externally threaded for connection to a sleeve section 36 which is provided with internal threads 31 at its upper end to fit the threads of the extension 34 of the member 3|. When the members 3| and 36 are screwed together, the flange 30 of the cup washer 21 is gripped between the shoulder 35 and a shoulder 38 at the upper end of the member 36. Adjacent the inner face of the cup washer 21 a shallow annular channel 40 is formed in the external face of the member 3|, and openings 4I connect this annular channel 40 with the interior passage or channel 42 of the member 3|. A valve seat 43 is held against a shoulder 44 disposed within theV ond cup Washer 21 is held by means of a suc-- ceeding sleeve member 36. Each of the sleeve members 36 has a valve seat 43 therein-and contains a valve ball 46. To limit the upward movement of each valve ball 46, the lower end of each fitting 3| or 3Ia may be provided with a diametrally extending bar 41 which may readily consist of a pin extending through openings 48 in the extension 34.

. In the manner above described the piston 26 consists of consecutive sections joined together to form a continuous tubular structure. Each of the sections has the sealing means 21 at the lower end thereof, and below the planes of the radial openings 4| adjacent the inner faces of the sealing means or cup washers 21 valve means 58 represented by the seats 43 and balls 46 are disposed to control the flow of fluid through the axial passage of the piston 26. During the upward stroke of the piston each of the valve means 50 is closed so that each of the cup washers in consecutive order may support a body of oil against the under face of the preceding cup washer, thereby dividing the pumping load between the series of cup. washers with which the piston 26 is provided.

For example, should the piston have five cup washers thereon and be operating against a head of one thousand pounds per square inch, the pressure in the spaces 85, 86, 81, etc., between the consecutive cup` washers may be nine hundred, eight hundred, seven hundred, etc., pounds per square inch, the pressure in each space being applied to the under face of the cup washer at the upper end thereof so that the differential of pressure between any two spaces is maintained at; a small amount, such as one hundred pounds per square inch. It will be recognized that the length of the piston may be varied to suit operating conditions and that the number of cup washers employed in the assembly'may be readily varied. As shown in Fig. 1, the lowermost sleeve 36 has its valve seat 5| held therein by a simple bushing 52.

The operation of the piston may be determined from the following. It is a well known fact that sand in oil being pumped accumulates in the anuular spaces formed adjacent the inner faces' thereof. During this downward stroke of the piston, oil passes upwardly through the piston as indicated by the arrow 53, thereby producing a suction adjacent the inner ends of the radial openings 4 I, with the result that oil is drawn from theV annular channel 48 through the passages 4'I into the upward flow of oil through the interior of the piston, carrying therewith such sand as may accumulate in the annular channel 48.

InFig. 5 I show the manner in which each pumping cup washer 21 may be preceded by a surface cleaning cup washer 21a. This is accomplished by placing between the upper end of -a sleeve 36 and a fitting 3 la atting 54 which is similar to the fitting 3 la with the exception that it is provided with a threaded counterbore 55 to receive the threaded extension 34 of the fitting 3Ia. The cleaning cup washer 21a is gripped between the shoulder 56 at the upper end of the member 54 and the radial shoulder 35 of the tting 3Ia. The washer 21a has no pumping effect but 'merely removes sand from the'face of the' barrel I8 ahead of the washer 21, thereby minimizing the wear on the cup washer 21. It will be readily seen that the pump piston 26 has means for preventingthe accumulation of sand adjacent the external sealing faces of the piston which operate in sliding engagement with the inner face of the pump barrel and therefore will operate with a minimum of wear since the pressure of the cup washers 21 against the inner face of the barrel I6 is determined only by oil pressure and not by pressure of accumulated sand or other foreign materials, and that the piston cannot become frozen or sanded up under ordinary operating conditions.

Accumulation of sand between and adjacent the frictional engaging faces of the piston and barrel of a pump of the general character now in use produces a friction load in addition to the pumping load of the head of oil being moved upwardly through the pump tubing by the piston. For example, this friction may produce a resistance against upward movement of the piston equal to the pressure of the oil so that the sucker rods and pumping mechanism are forced to carry twice the load which would be carried were the piston operating freelg. As the sand accumulates,

the friction load becomes greater and greater until Y finally the piston is relatively immovable; and as the friction' load increases, the elongation of the string of sucker rods at each pumping stroke increases so that the sucker rods become fatigued in a much shorter length of time than where they are operating under conditions of free movement of the piston within the pump barrel. My new pump, by prevent-ing accumulation of sand on the exterior of a. pump piston, keeps the friction load at a minimum, thereby maintaining the power required for pumping at a minimum, minimizing the elongation of the string of sucker rods, and accordingly increasing the production of oil. It will be recognized that 'vhere the friction load is great and the sucker rods are correspondingly stretched, the movement of the piston within the barrel is reduced so that its pumping effect is correspondingly reduced. By keeping the friction of the piston at a minimum point, a. maximum movement of the piston is maintained, with the result of a maximum production of oil from the well.

In Fig. 4 I show an alternative construction whereby the results specified relative to the form of the invention shown in Fig. 1 may be obtained. The piston 60 has at its upper end an annular member 6I adapted to be secured to the lower end of the tubular member 32 which extends upwardly within the pump barrel I6 and further serves as a guide means for the piston or plunger. The annular member 6I has an inner cylindrical surface 63 leading upwardly from its lower end to internal threads 64 which are spaced from its lower end as shown. Secured to the lower part of the annular member 6I is a sleeve or section member 65 having a tubular extension 66 of reduced diameter having a lthreaded upper end 61 so that the extension 66 will project within the cylindrical face 63 and engage the threads 64 of the member 6I. Between shoulders 68 and 16 provided respectively by the members 6I and 65 cup washers 'II are gripped so as to be held in operating position. Adjacent the inner face of each cup washer 1I radial openings 12 are provided through which oil may circulate so as to remove sand which tends to accumulate within the cylindrical portion of the cup washer. 'I'he section member 65, like the member 6I, has a cylindrical face 63 within the lower end thereof followed by threads 64 so that the tubular extension 66 of a following section 65 may be secured thereto in the same manner as the first of the sections 65 is secured to the member 6I. Within each of the sections 65 valve means 14 are disposed, the seat member 15 of each valve means being held in place against a shoulder 'I6 by the upper end of the tubular extension 66 of the succeeding section member 65. To limit the upward movement of the valve means 14, pins 18 may be placed diametrally across the section members 65. For any given size of pump a valve ball of relatively large size may be employed, since such valve balls are disposed within the sleeve or section members 36 or 65.

As will be noted in Figs. 2 and 4, the upper end of each annular member 3I and 6|provides a shoulder 62 which projects beyond the surface of the tubular member 32 so that when the piston 26 is lifted above its ordinary working position within the barrel I6, the shoulder 62 will engage the shouider23 of the fitting 20 and lift the barrel I6 from the barrel receiver I3. The yoke member 33 has a shoulder 90 adapted to engage the upper end of the fitting 20 before the lower end of the piston can engage the valve mechanism at the lower end of the cylinder I6, so that the force required to seat the barrel I6 in the barrel receiver may be transmitted from the sucker rods to the barrel I6 without possibility of injuring any part of the piston 26 and so that dropping of the piston through any cause cannot result in the lower end of the piston striking the valve means at the lower end of the barrel I6.

Although I have herein shown and described my invention in simple and practical form, it is recognized that certain parts or elements thereof are representative of other parts, elements, or mechanisms which may be used in substantially the same manner to accomplish substantially the same results; therefore, it should be understood that the invention is not to be limited to the details disclosed herein but is to be accorded the full scope of the following claim.

I claim as my invention:

A pump piston of the character described, adapted to be operated in a pump barrel in a well, including: a plurality of cup washers of a size to t said barrel, each cup washer having a cylindrical portion and a radial flange portion; a plurality of tubular members having an external diameter nearly as large as the internal diameter of said barrel; cooperating threaded means at the ends of said tubular members for connecting them together to form a piston having a passage for pumped liquid extending from end to end thereof, there being valve seat receiving shoulders associated with said threaded means for positioning and sealing valve seats within said tubular members, there being cooperating external shoulders formed in conjunction with said threaded means for engaging said radial ange portions of said cup washers when said threaded means are screwed together to connect said tubular members in end-to-end relationship, and there being a group of small openings disposed in the wall of said piston behind each of said cup washers connecting the inner wall of each cup washer with the passage through said piston; a plurality of annular valve seats, the number of said valve seats corresponding to the number of said cup washers, and one each of said valve seats being held in place in said passage of said piston by said valve receiving shoulders below the plane of the cup washer to which it corresponds; and a valve closure member disposed above each of said valve seats for closing engagement therewith.

ANTHONY E. CARLSON.

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