US3395923A - Self-lubricating stuffing box - Google Patents

Description

6, 1968 M. A. REMKE ETAL 3,395,923

SELF-LUBRICAT ING STUFFING BOX Filed July 9, 1965 2 Sheets-Sheet l 47 7 2 3 I 48 49 -LF 52 f 39 INVENTORS M. A. REMKE BY F. e. L YTE A TTORNEYS Aug. 6, 1968 M. A. REMKE ETAL SELF-LUBRICATING STUFFING BOX Filed July 9, 1965 2 Sheets-Sheet 2 FIG. 4

FIG. .5

IN VEN TORS M. A REMKE BY F. c. LYTE A T TORNEV Unitd States Patent 3,395,923 SELF-LUBRICATING STUFFING BOX Marvin A. Remlre and Frank G. Lyte, Bartlesville, Okla,

assignors to Phillips Petroleum Company, a corporation of Delaware Filed July 9, 1965, Ser. No. 470,835 2 Claims. (Cl. 277-59) ABSTRACT OF THE DISCLOSURE In an oil well tubing head having a chamber connected to the tubing, with a stufiing box at the top of the chamber, a polished rod reciprocating through said box and chamber, and an oil outlet conduit to said chamber, the improvement comprising an oil-retaining cup slidably mounted on said rod and secured in said chamber, with said oil outlet conduit connected to said chamber at a point at least as high as the top of said cup, whereby when oil passes from said tubing out said conduit it will also fill said cup which will retain said oil in contact with said rod for a substantial period of time. A further improvement is a helical spring around the rod between the stufiing box packing and packing between the cup and rod to separate the two packings and urge them into packing contact with the rod.

This invention relates to a self-lubricating stufiing box. In one aspect it relates to such a stufiing box for an oil well tubing in which there is an oil reservoir positioned to receive and retain a small portion of the oil being pumped in such a position that the polished rod during pumping is reciprocated through the oil in said reservoir so as to maintain an oil layer on the surface of said polished rod and obviate pulling a dry rod through the packing in the stufiing box and thereby destroying said packing.

In the prior art, difliculty has been experienced due to the surface of the polished rod drying out between the times that oil is being produced from the well and pumped to the surface through the tubing by a reciprocating movement of said polished rod through the packing in said stufiing box.

The dried-out polished rod will stick against the packing and soon tear the same to pieces.

While attempts have been made in the prior art to lubricate such stufiing boxes, such attempts are generally unsuccessful. This lack of success is due in part to the poor design of the lubricating means, and in part to the operator forgetting to actuate or renew the lubricating means.

The present invention avoids these objectionable features of the prior art by maintaining a reservoir of oil obtained during pumping in a position where the polished rod passes through the same so that the polished rod remains wet with oil, or is immediately wetted with oil upon restarting the pump, so that it will not adhere to the packing and tear up the same. Means is provided to readily renew the body of oil in said reservoir whenever oil is pumped.

One object of the present invention is to provide an improved self-lubricating stufiing box. Other objects are to provide improvements in the elements employed in such stufiing boxes.

Numerous other objects and advantages will be apparent to those skilled in the art upon reading the accompanying specification, claims and drawings.

FIGURE 1 is an elevational view With parts broken away in cross section of a stufling box embodying the present invention.

FIGURE 2 is a cross-sectional view of the apparatus 3,395,923 Patented Aug. 6, 1968 "ice of FIGURE 1 taken along the line 22 looking in the direction indicated.

FIGURE 3 is an elevational view with parts broken away in cross section of a second modification of the stufiing box.

FIGURE 4 is a similar elevational view with parts broken away in cross section of a third species of the present invention.

FIGURE 5 is an elevational view with parts in cross section showing the present invention applied to the tubing of an oil well.

FIGURE 6 is an elevational view of one form of stufling box packing shown in FIGURE 4.

FIGURE 7 is an elevational view of a second form of stuffing box packing that could be used in place of that shown in FIGURE 6.

In FIGURE 1 a tubing head 11 is shown containing a self-lubricating stufling box for the top of an oil well tubing. The tubing head 11 is provided with threads or other connecting means 12 adapted to be connected to the tubing 13 (see FIGURE 5) of a pumping oil well through which oil 14 is at least intermittently pumped by a pump (not shown) inside pumping housing 16 actuated be a reciprocating polished rod 17 passing into said tubing 13 through said head 11. The head 11 has a vertical conduit 18, 19, 21, 22, 23 and 24 passing said rod, a chamber 26 forming a portion of said conduit, and a branch conduit 27 being connected to said chamber for the outlet of oil pumped into said chamber by said pump.

This improved self-lubricating structure comprises in combination an oil-retaining cup 28 mounted in said chamber 26 around said rod 17, a lower packing 29 between the body of said cup 28 and said rod disposed to form an oil-retaining space 31 between said rod 17 and said cup 28 above said packing 29, and a stufiing box having upper packing 32, 33 and 34 disposed at the top of said chamber 26 and sealing between the body 36 of said head and said rod 17 above said oil-retaining space 31 and said branch conduit 27.

While not essential to the invention, it is preferred that in the cup 28 around the rod 17 and between the lower packing and stuffin g box there is disposed an upper packing follower 37, a lower packing follower 38 and a helical compression spring 39 separating the two followers and urging them against their respective packing 32, 33, 34 and 29.

In FIGURE 1 the upper and lower packing comprises conical resilient packing rings 29, 32, 33 and 34. While not necessary to the invention, it is also preferable in some instances to provide a resilient dust-wiping ring 41 retained in groove 42 of a stufling box follower 43 preferably threaded at 44 into stufiing box head 36, which in turn is retained by nuts 46 and bolts 47 to the top of tubing head 11. While not essential, tubing head 11 is often provided with an outlet 48 of lesser diameter than oil outlet 27 for the purpose of removing samples of gas, measuring pressure or the like. Cup 28 is provided with a plurality of windows 49 allowing free passage of oil between cup 28 and tubing head chamber 26. The bottom of cup 28 is supported on ring 23, which may be supported on radial fins 51 in the chamber 26. However, other suitable means of supporting the cup obviously may be employed.

During pumping, oil coming up passage 24 through chamber 26 to flow line 27 overflows through windows 49 into cup 28, filling the same up to the level 52 of the bottom of windows 49. Later, when no oil is being pumped, the reservoir of oil in 28 up to level 52 acts to keep the polished surface of rod 17 wet with oil. Even if the oil dries out above level 52, as soon as the rod 17 again is reciprocated some of the oil will be carried on its surface up into the upper packing 41, 32, 33 and 34 and, of course, into the lower packing 29 so that the packing will not be destroyed by a dry rod 17.

FIGURE 2 is a cross section of FIGURE 1 and needs no further explanation.

FIGURE 3 is a second embodiment of the present invention in which the upper packing 53 comprises loose packing material and a grease nipple 54 in said stufiing box accessible from the outside of said tubing head 11 is connected to supply grease to fill the space in said loose packing 53. When not using the follower 43 and dust ring 41 of FIGURE 1, a simple follower or closure means 56 may be substituted at 44.

In FIGURE 3 the cup 57 is provided with an integral bottom 58, a lower rubber packing washer 59 and a steel follower 61 below helical compression spring 62 which presses upwardly on upper follower 63 provided with spring centering boss 64 against loose packing 53 retained in cup 57 by threaded cover 66.

Although not essential, if desired a rubber O-ring 67 may be provided in an annular slot in the top of cover 66 to seal against head 36 to prevent the escape of fluid from chamber 26 through the central passage in 56.

Parts having the same number are the same as parts shown in FIGURE 1.

All the various packing members 41, 32, 33, 34, 29, 67, 59, 68, 69, 71 and 72 may be made of oil-resistant synthetic rubber, such as Neoprene (trademark), and the same or other well known material can be used for gaskets 73. Hemp or polyolefin fiber can be used as packin 53.

In FIGURE 4, tubing head 11 has a cap 74 with an upper thread end 76 into which a retaining ring 77 is threaded. Retaining ring 77 holds down the top of cup 78 which has an open top closed by follower 79 which may be provided with annular O- rings 71 and 72. Between spring 62 and follower 79 is disposed a helical tube of resilient material 69, the elevation of which is shown in FIGURE 6. The inner surface of 69 may be provided with an annular saw-tooth surface 81 to provide a series of horizontal serrations or annular ridges on its inner surface wiping on rod 17. As shown in FIG- URE 3, the lower packing may be a flat ring of resilient material 59.

In FIGURE the stufiing box 11 of FIGURE 1 is shown applied to an oil well generally designated as 82. The well comprises a well bore 83 extending down through geological formations 84, 86, 87 and part of 88. Oil from oil bearing formation 87 passes through holes 89 in casing 91 and rises by natural hydrostatic pressure to level 92. Casing 91 is provided with a casing head 93 supporting a tubing support ring 94 in which tube 13 is secured. Stufling box 11 is secured in tubing 13.

A Samson post 96 supports a walking beam 97 which is actuated by a pitrnan 98 to reciprocate polished :rod 17, which rod extends through stufiing box 11 down through tubing 13 to a pump (not shown) in pump housing 16. When reciprocated, pump 16 tries to pump oil 14 up tubing 13 through stufling box 11 and out oil flow line 27. However, in many wells the oil level 92 is pumped down below the intake of pump housing 16, upon which rod 17 is liable to be wiped clean of oil and dry out. Pumping is discontinued. In the prior art, when pumping is renewed, dry rod 17 will tear up the packing. In the present invention, the cup 28, 57 or 78 will retain a reservoir of oil up to level 52 at the bottom of windows 49, so that when pumping is renewed polished rod 17 is still wet with oil or is made wet with oil on the first stroke of the pump, thereby lubricating the packing and preventing the rod from tearing up the packing. It is therefore obvious that we have provided a selflubricating stufiing box for an oil well tubing as claimed below.

FIGURE 6 is an elevational view of the helical tubular rubber packing 69 of FIGURE 4.

FIGURE 7 is an elevational view with a portion in cross section of an annular tubular rubber packing 68 which can be substituted for packing 69 in FIGURE 4.

While certain specific embodiments of this invention have been illustrated in the drawing and described in the specification in order to explain the invention, it is obvious that the invention is not limited thereto.

Having described our invention, we claim:

1. A polished rod stufiing box assembly comprising in combination:

a tubing head having a body adapted to be secured to an oil well tubing, said body having a first vertical passage therethrough, the bottom of which passage is adapted to be connected in communication with said tubing;

said first vertical passage being adapted to have a reciprocating polished rod passed therethrough in spaced relation therewith;

said body having a chamber forming a part of said first vertical passage;

an oil-retaining cup secured to said body with the top,

the wall and the bottom of said cup in spaced relation to the wall of said chamber inside said chamher, with a vertical second passage through the bottom of said cup adapted to have said polished rod passed therethrough. in spaced relation to the wall of said cup;

first packing means secured in the bottom of said cup adapted to restrict the flow of oil between said cup and said rod and thereby to form a substantial oilretaining space between said rod and said cup from above said first packing to the top of said cup;

the top of said cup communicating with said chamber;

second packing means secured in said body adjacent the top of said chamber adapted to restrict the How of oil between said body and said rod; and

a conduit connected to said chamber at a point at least as high as the top of said oil-retaining space in said cup for the outlet of oil from said chamber;

whereby when oil passes from said tubing out through said conduit is will also positively fill said oil-retaining space in said cup by gravity flow over the top of said cup, and then said cup will retain said oil in contact with said rod for a substantial period of time.

2. The combination of claim 1 in which in the cup around the rod and between the first and second packing means there is disposed a helical compression spring separating the two packing means and urging them into packing contact with said rod.

References Cited UNITED STATES PATENTS 1,585,087 5/1926 Dcems 277-4 X 1,594,935 8/1926 Force 277--S9 2,538,207 1/1951 MacArthur 27710O 2,628,112 2/1953 Hebard 277-68 X 1,603,206 10/ 1926 Hull 277-62 X 1,805,155 5/1931 Weeks 277-72 X 1,877,696 9/ 1932 Schellack et al 277-72 X SAMUEL ROTHBERG, Primary Examiner.

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