US3361040A - Pump plunger - Google Patents

Description

. Jan. 2, 1968 R. L. CHENAULT 3,361,040

PUMP PLUNGER Filed Oct. 6, 1965 M/VE/VTOR 190) L. CHE/VAULT Attorney United States Patent Ofifice 3,361,040 Patented Jan. 2, 1968 3,361,040 PUMP PLUNGER Roy L. Chenault, Dallas, Tex., assignor to United States Steel Corporation, a corporation of Delaware Filed Oct. 6, 1965, Ser. No. 493,503 5 Claims. (Cl. 92-180) ABSTRACT OF THE DISCLOSURE A plunger for use in subsurface oil well pumps, The plunger has metal surfaces which provide a metal-to-metal seal with a pump barrel and a soft packing between the metal surfaces. One of the metal surfaces is formed on a radially adjustable sleeve to facilitate aligning the parts.

This invention relates to improved plungers for subsurface oil well pumps and the like.

An object of the invention is to provide improved plungers which combine the advantages of a closely fitted metal-to-metal seal with those of soft self-adjusting packmg.

A further object is to provide improved plnngers which incorporate a self-cleaning feature, whereby flow through the plunger is directed over the top thereof to prevent sand and other foreign material from settling and accelerating Wear of both the plunger and pump barrel.

In the drawing:

FIGURE 1 is a half side-elevational, half sectional view of a plunger constructed in accordance with my invention; and

FIGURE 2 is a similar view showing a modification.

The plunger shown in FIGURE 1 includes a unitary tubular metal body which has a pair of vertically spaced downwardly facing shoulders 12 and 13 intermediate its length, and an externally threaded portion 14 at its lower end. I fit soft packing 15, preferably in the form of chevron rings, around the plunger body abutting shoulder 12. I fit a metal sleeve 16 around the plunger body abutting both shoulder 13 and the lower end of the packing 15. I mount a nut 17 and a bushing 18 on the threaded portion 14 of the plunger body to hold the parts assembled. The upper face of nut 17 has a circular groove which contains an O-ring 19. The O-ring abuts the lower end of sleeve 16 to afford a seal. The bushing 18 is designed to carry a conventional valve cage (not shown). Both the sleeve 16 and the upper portion 20 of the body 10 are designed to have a close metal-to-metal fit within a conventional pump barrel 21. The sleeve has clearance with the body 10, as indicated at 22, to facilitate aligning the sleeve with the upper portion 20 when I insert the plunger in the pump barrel. The body 10, nut 17 and bushing 18 have a series of wrench flats 23 to facilitate assemblying the parts.

The upper end of the body 10 carries a cage 24 which has threads 25 to receive a conventional valve rod (not shown). The cage has slots 26 for delivering fluid from the interior of the plunger to the space thereabove. These slots are located immediately above the top of the plunger body 10. This arrangement eliminates any settling space above the plunger where sand and other foreign material can collect and accelerate wear on both the plunger and pump barrel.

FIGURE 2 shows a modification in which the upper portion of the plunger body 10a carries a second removable metal sleeve 27. This sleeve furnishes the metal-tometal contact with the pump barrel in place of the body itself. The body has an upwardly facing shoulder 28 which the lower end of sleeve 27 abuts. Cage 24a abuts the upper end of sleeve 27 to hold the parts assembled. I can fit sleeve 27 tightly on the plunger body, since clearance between sleeve 16 and the body enables the latter sleeve to align itself with sleeve 27. In other respects the modification is similar to FIGURE 1; hence I do not repeat the description. The modified construction has a further advantage that it decreases the cost of replacing the wearing parts, since the plunger body itself is not exposed to wear against the pump barrel.

Most deep well pumps have all-metal plungers and rely on a close metal-to-metal fit between the plunger and barrel to furnish a seal. Leakage of fluid past a closely fitted metal-to-metal plunger-and-barrel combination varies with the cube of the diameter clearance. For example, a plunger of given length with a clearance of 0.003 inch in the barrel has a leakage rate 27 times that of the same length plunger with a clearance of 0.001 inch. Increasing the plunger length diminishes leakage only in proportion to the first power of the plunger length. By including the soft packing intermediate the areas of metalto-metal contact, I minimize leaking or eliminate it altogether. The areas of metal-to-metal contact also serve to protect the packing from abrasive particles of any appreciable size, and therefore prolong its life. Thus the combination of the two forms of seal affords the advantages of each and produces a much longer life for both.

The arrangements illustrated are for use in a pump which has a stationary barrel and a reciprocating plunger. By merely inverting parts, I can use a similar arrangement in a pump which has a stationary plunger in a traveling barrel.

While I have shown and described certain preferred embodiments of my invention, it is apparent that other modifications may arise. Therefore, I do not wish to be limited to the disclosure set forth but only by the scope of the appended claims.

I claim:

1. A pump plunger comprising a tubular body, means on the upper portion of said body providing a surface adapted to form a metal-to-metal seal within a pump barrel, said body having a pair of vertically spaced downwardly facing shoulders intermediate its length, soft packing surrounding said body and abutting one of said shoulders, a metal sleeve surrounding said body below said packing and abutting both the packing and the other of said shoulders, said sleeve providing a second surface adapted to form a metal-to-metal seal within the barrel, a nut threadedly engaging the lower portion of said body below said sleeve and abutting the lower end of said sleeve, and a sealing ring between said nut and said sleeve, said sleeve having clearance with the portion of said body which it surrounds to permit relative radial movement be tween said sleeve and said body after the nut is fixed on said body and thereby facilitate aligning the two surfaces which form metal-to-metal seals.

2. A plunger as defined in claim 1 in which said means is integral with said body.

3. A plunger as defined in claim 1 in which said means is in the form of a second sleeve removably mounted on said body.

4. A plunger as defined in claim 1 further comprising a cage fixed to the top of said body, said cage having slots located immediately above said body to eliminate any 5 References Cited UNITED STATES PATENTS 5/ 1920 MacKenzie 92180 X 4 OBannon 92-180 X Bertrand 92-257 X Eklund 92-180 X Whitney 92-180 X Thassy 92'-258 X Hyatt a- 92-258 X Gordon 92240 EDGAR W. GEOGHEGAN, Primary Examiner.

MARTIN P. SCHWADRON, Examiner.

G. N. BAUM, Assistant Examiner.

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