US2628112A - Self-aligned lubricating stuffing box - Google Patents

Description

Feb. 10, 1953 G. G. HEBARD 2,628,112

SELF-ALIGNED LUBRICATING STUFFINGBOX l BYMMM Feb. 10, 1953 G. G. HEBARD 2 SHEETS- SHEET 2 INVENTOR.

G.G. HEBARD BYQMM A TTORNEVS Patented Feb. 10, 1953 SELF-ALIGNED LUBRICATING STUFFING BOX Glen G. Hebard, Bartlesville, Okla., assignor to Phillips Petroleum Company, a corporation of Delaware Application November 14, 1949, Serial No. 126,986

3 Claims. (Cl. 286-15) This invention relates to polish rod stuffing boxes. In one specific aspect it relates to a self-aligning stuffing box for use with polish rods in a sucker rod actuated oil well pump assembly. In another aspect it relates to a selfaligning polish rod stuffing box that adjusts its position to conform with the irregularities of movement of the polish rod during pumping operations.

In the art of polish rod stuffing boxes a large proportion of the failure of such stuffing boxes is due to misalignment of the polish rods during pumping operations. Another reason for failure of such stuffing boxes is due to the frequent tightening of the packing gland by the pumper even when tightening is not necessary.

An object of this invention is to provide a polish rod stufng box which is self-aligning and adapted to compensate for irregularities in motion of the polish rod.

Another object of my invention is to provide a polish rod stufng box in which that portion containing the packing is self-aligning.

Another object of this invention is to provide a polish rod stuffing box in which that portion of the box containing the packing moves in a lubricating reservoir.

Still another object of this invention is to provide a pressure lubricated self-aligning polish rod stumng box.

Still other objects and advantages of my invention will be apparent upon reading the following description which when taken with the attached drawing forms a part of this specification.

In the drawing,

Figure 1 is an elevational view, in section, of my self-aligning stuffing box assembly.

Figure 2 is a diagrammatic representation of a tubing head assembly including the self-aligning stumng box and lubricator in operative relationship.

Referring now to the drawing and specifically to Figure 1, reference numeral II refers to a cylindrical housing member which contains the floating gland assembly I2 of my invention. At a point near the top of the cylindrical housing II is attached by welds I1 or other means, a flange member I5. This flange member I contains bolt holes I5 for use in attaching an upper flange or cap member I3. This cap ange member I3 is generally round in shape and has bolt holes I4 that align with bolt holes I6 in ange I5. Bolts 25 when inserted rigidly attach the cap fiange to the main body of the packing as- 2 sembly. This cap flange is provided with a cen trally disposed opening 35 to accommodate a polish rod 24. The opening 36 is sufficiently large that the polish rod will not touch the walls of the cap flange I3. The lower portion of the housing II is attached to a housing base 22 by a weld 38. The lower portion of the housing base 22 has threads 40 for assembly into the pumping T. This housing base 22 is provided with a bushing 23 which may be of brass or bronze so that upon contact with a polish rod the bushing will be the element worn. The top portion 0f the housing base and the lower surface of the cap flange form plane and parallel ends of a cylindrical main housing in which the self-aligning packing elements are contained. Resting upon the bottom plane surface 2| is a lower bearing ring 20. This lower bearing ring '28 has its bottom so constructed as to form a plane surface B3 for resting upon the surface 2l. This bearing ring also is of a smaller diameter than the diameter of housing II so that as the occasion arises this bearing ring may move horizontally as required by the horizontal movement of the polish rod 24. This bearing ring 2o is provided with an opening 50 at its center through which the polish rod is disposed with the diameter of this opening suiiiciently large so that the polish rod will not touch the bearing ring at any time. Disposed against the bottom surface of the cap flange I3 is an upper bearing ring I8. This upper bearing ring I8 is similar in construction to the lower bearing ring 2D, but of course is inserted in the apparatus so that its plane surface will be in contact with the underside of the cap ange. The top plane surface of the bearing ring I3 is identified by the reference numeral 62, while the opening in its center for the accommodation of the polish rod is identied by reference numeral 31. The lower surface of the upper bearing ring I3 and the upper surface B4 of the lower bearing ring 2i) are spherical surfaces. The floating gland is disposed between these two spherical surfaces. The top spherical end surface 31 of the gland body I9 is convex upward while its lower end surface 65 is also a spherical surface and convex downward.

The packing gland body I9 has a channel 39 along its axis to accommodate the polish rod and packing elements. In the lower part of the body i9 this channel 39 is just slightly larger in diameter than the diameter of the polish rod, but in the remainder of the body the channel is sufficiently large to accommodate the packing elements. These packing elements include an upper metal packing ring 4I, inverted V-packing rings 42, a lantern ring 43, some V-type packing rings 44, a center metal ring 45, some V-type packing rings 46 and a lower` metal packing ring 47. Inserted immediately below this metal packing ring Il? is a spring guide 49 and a compression spring 4B. When these packing elements are installed in the assembly the pressure exerted by the compression spring 48 is the only pressure exerted against the packing members and by this type of spring loading, the pumping operator cannot subject the packing to a greater pressure as he can do with conventional stu'ing boxes by giving the packing gland vnuts a half turn or so as he visits the wells.

For lubrication purposes an opening 54 is provided in the housing II for insertion of 'a tubing or other fitting for transfer of lubricant from an outside source into a lubricant space 25 and associated lubricant spaces. These associated spacesare openings 5S in the packing gland body member I9, the openings 52 in the lantern ring 43 and the spaces 5I between the lantern ring and gland member, and between the polish rod and the gland body. A plurality of openings 53 and 52 are provided so that there will be free flow of lubricant from the space 26 to the packing elements.

In the lower surface of the cap flange I3 is a groove 28 in which is disposed an O-ring 32 made of lresilient material. In the top spherical surface of the packing gland body I9 is a groove 29 which also contains an O-ring 33 made of resilient material. In like manner the upper plane surface of a housing base 22 contains a groove 3| containing an O-ring 35 and the lower spherical surface of the gland body I9 contains a groove 30 and an O-ring 34.

In assembling the apparatus of Figure 1 the cylindrical housing II and base member 22 are slipped down over the polish rod and attached to a pumping T |04 (of Figure 2) by threads 40. The wear bushing 23 is next inserted, followed by the insertion of the O-ring 35. The lower bearing ring is next positioned. The O-ring 34 may preferably be placed in its retaining groove 30 prior to positioning of the gland body I9. After this gland body I9 is lowered into place, the spring guide 49 is inserted followed by the spring 48. The lower packing ring il is now dropped into place and the packing rings 45, ring 45, packings 44, lantern ring 43, packings 42, and the packing ring 4I, are positioned in succession. r-Ihe -0ring 33 may have previously been placed in its groove V29 or it may now be placed. The upper bearing `-ring I8 is next positioned and nally the cap flange with the O-ring 32 in groove 28 is placed lupon this packing assembly. Bolts are then inserted and tightened. If desired a groove 55 may be made in the lower surface of cap flange I3 for accommodation of the upper end of the housing member II. A gasket 55 of resilient Vmaterial should preferably be placed in this groove 55 in order to obtain a iluid-tight seal at this joint.

The compressionspring 48 is of such magnitude that when the bolts 25 are tightened so that the cap flange I3 is rmly in place the force exerted -by the spring y48 upwards against the assembly of packing elements 42, I4 and -40 will be substantially constant throughout the life of the packing and therefore .provid-e a uniform seal. The design of this spring may be varied from well to Well as packing conditions or problems at 4 a particular well arise. Lubricant within chamber 26 flows through channels 53, channels 5I and 52 so that all elements which are in contact with the polish rod will be lubricated to reduce friction and provide a tight seal against pumping pressure.

Referring now to Figure 2, the self-aligning packing assembly I 05 is shown diagrammatically. Polish rod 24 extends above and below this packing assembly. Attached to the threads 40 of the housing base is a pumping T |04. T |04 in turn is attached to the top coupling of a well tubing IOI by means of some threads |02. A flow line |03 carries the pumped fluid `from the well to tanks, not shown. A pressure tap II'I may be made into the flow line |03 for pressurizing of a lubricator assembly |06. This assembly is held firmly in relation to the packing assembly by a clamp III.

This lubricator assembly |06 consists of a lubricant chamber II2 within a body -member |25. In this chamber is a piston ||3 connected to a guide and indicator rod II5. A cap member .I I6 covers the lower end of the body |25. A compression spring IIII is disposed between this cap IIE and the piston IIS so as to exert at all times a pressure against the lubricant. At the top end of the chamber |25 is a T |24. The side outlet of this T is connected by a conduit I2I to a fitting |27 which is inserted in opening 54 (see Figure 1). When pressure is exerted against the lubricant in the chamber I|2, lubricant is urged to flow through fitting |24 and conduit I2I into the packing gland.

Opening |22 in fitting |23 which is in the top end of the T |24 is for introduction of new lubricant from an exterior source into the apparatus without dismantling any portion of the apparatus. A valve |26 is for removal of the lubricant.

At the bottom portion of this lubricator assen bly are several small pipes IIB and II'I, Pipe III is provided with a valve |20. Pipe I|1 provides uid communication .between flow line |03 and the underside of the piston I I3. When valve |20 is open, tubing head pressure is communicated through conduit II I to the underside of the piston and this pressure in addition to the pressure of the spring I`I4, tends to force lubricant into the polish rod packing assembly. When valve |25 is open, valve I| 9 in tube II8 should be closed in order that pressure will not escape. If it is desired to force the lubricant into the packing assembly by spring I I4 alone, then valve |20 may be closed and valve I I9 opened.

True straight line motion cannot be obtained 1n the present day pumping unit, consequently in addition to moving vertically, the polish rod also moves horizontally in a more or less wobble action. In addition, pumping equipment such as oil well .pump-ing jacks and the like may frequently be slightly out of line which adds greatly to the normal wobble of a polish rod. This wobble motion in polish rods is an important reason for rapid failure of polish rod packing. -However, in the packing gland of my invention, 1f the .polish rod vibrates or moves horizontally during its up or down stroke, the inner assembly consisting of the upper bearing ring I 8, the lower bearing ring 20 and the packing gland body with its packing may move horizontally with the polish rod. This horizontal movement is actually between the surfaces 6I and 62 at the top land between the surfaces `63 and 2| at the bottom. Any-wobble 'action movement of th'epolish r'od is compensated for by the rotation of the packing gland body I9 on its upper and lower spherical surfaces.

In actual use, packing gland assemblies constructed and installed according to my invention have been used as long as seven months in continuous operation in contrast to periods as short as one month and. yless when conventional rigidly xed packing gland assemblies are used.

The V-type pack- ing elements 42, 44, and 48 may be obtained lcommercially as such elements have long been used for many packing purposes. These packing elements should of co-urse be resistant to action of hydrocarbons such as will be present in oil Well production fluid. They should also be resistant to any action exerted by the lubricant. In like manner, the O- rings 32, 33, 34, and 35 should be `composed of resilient material which is not affected under the conditi-ons of their use.

The O-ri-ngs used in this appara-tus may be considered as functioning in the Ifollowing manner. The 0-rings 35 and 34 which are nearest the tubing head may be exposed to a pressure higher than the other O-rings. Well head fluid pressure from the opening 50 which exerts itself between the plane surfaces of conta-ct $3 of the lower bearing ring and the upper surface 2| of the base plate 22, respectively, will be transmitted into the groove 3| on the side of the 0-ring nearest the polish rod. This pressure will then tend to force the O-ring 35 radially away from the polish rod to effect a, seal against the escape of high pressure fluid from the space 50 to the space 26. In like manner, tubing head fluid pressure which may be transmitted along the spherical surfaces 64 and 66 is sealed by O-ring 34. Since the pressure in the space 26 is normally greater than atmospheric pressure, O- rings 32 and 33 are urged into sealing engagement against leakage of lubricant, as shown.

The above-described detailed embodiment is given for illustrative purposes and should not be regarded as limiting the invention, the scope of which .is set forth in the following claims.

Having described my invention, I claim:

1. A self-aligning mounting structure for the packing of a polish rod packing gland comprising, in combination, a housing adapted to be secured to an oil Well pumping T, the interior of said housing defined by la cylindrical side wall and parallel top and bottom end walls normal to the axis of the cylindrical side wall, a top bearing ring having a top plane surface in sldable contact with said top end wall and a bottom spherical surface concave downward, a bottom bearing ring having a bottom Aplane surface in sldable contact with said bottom end wall and a top spherical surface concave upward, a hollow cylindrical floating packing gland body member disposed, in genera-l, con-centrically within the cylindrical side wall of said housing, said body member being open at its top end and having a bottom end wall, said housing, said top and bottom bearing plates and said bottom end wall of said body member having openings concentric with their respective axes to accommodate a polish rod, the inner diameter of said hollow oating body member being sufliciently large to accommodate annular packing rings adapted to surround said polish rod, and the surfaces of the top and bottom ends of said hollow cylindrical floating body member being spherical zones of the same radius as the spherical ysurfaces of the top and bottom bearing rings.

2. In the self-aligning mounting structure of claim 1, an O-ring seal in sealing relation between the top plane surface of the top bearing ring and the top end Wall of said housing, an O-ring lseal in sealing relation between the bottom plane surface of the bottom bearing ring and the bottom end wall of said housing, an O-ring seal in sealing relation between the bottom spherical surface of the top bearing ring and the top convex upward end of said iioating gland body member and an O-ring seal in sealing relation between the top spherical surface of the bottom bearing ring and the bottom convex downward end of said floating gland body member.

3. A self-aligning polish rod stuffing box assembly comprising, in combination, la housing adapted to be secured to an oil well and having parallel interior plane top and bottom end walls, a top bearing plate having a top plane surf-ace in sldable contact with said top end wall and a bottom spherical surface concave downward, a bottom bearing ring having a bottom plane surface in sldable contact with said bottom end wall and a top spherical surface concave upward, a oating packing gland for .packing la substantially axially disposed polish rod compri-sing a cylindrical body member dis-posed substantially axially within said housing, said housing, said top and bottom bearing plates and said body member having openings to accommodate said polish rod land packing in -said body member surrounding said polish rod, the surfaces of the top and bottom ends of said body member being spherical zones of the sam-e radius as, and disposed in contact with, the spherical surfaces of the top and bottom bearing rings whereby disalignment of said polish rod may be accommodated for.

GLEN G. HEBARD.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 774,270 Palmer Nov. 8, 1904 1,529,874 Culbertson Mar. 17, 1925 1,712,868 Boynton May 14, 1929 1,902,360 Foster Mar. 21, 1933 2,180,880 Poulsen Nov. 21, 1939 2,210,826 Williams Aug. 6, 1940 2,235,289 Dunn et al Mar. 18, 1941 2,267,183 Williams Dec. 23, 1941 FOREIGN PATENTS Number Country Date 192,288 Great Britain Feb. 1, 1923 322,403 France June 24, 1902 OTHER REFERENCES The Oil Weekly of July 13, 1936, page 64, Self-Aligning Stuing Box. (Copy in Div. 52.)

Images