US2573832A

US2573832A - Rod packing

Info

Publication number: US2573832A
Application number: US678091A
Authority: US
Inventors: Callahan Harold
Original assignee: Individual
Current assignee: Individual
Priority date: 1946-06-20
Filing date: 1946-06-20
Publication date: 1951-11-06
Anticipated expiration: 1968-11-06

Description

Nov. 6, 1951 H. CALLAHAN- 2,573,832

' ROD. PACKING Filed June 20, 1946 2 SHEETS-SHEET 1 3 woe/rm HA/FOLD CA1. z HHAN H- .CALLAHAN Nov. 6, 1951 ROD PACKING 2 SHEETS-SHEET 2 Filed June 20, 1946 3mm HnxoLa aqua/mu W NQTRQNM Patented Nov. 6, 1951 UNITED STATES PATENT OFFICE.

BOD PACKING Harold Callahan, Tulsa, Okla.

Application June 20, 1946, Serial No. 678,091

Claims. 1

The present invention relates generally to the rod packing art, and more particularly to an improved stuffing box assembly adapted to seal a wellhead casing about the reciprocating polish rod of an oil well pump.

In the pumping of oil wells which have insufiicient natural pressure to force the oil to the surface of the ground, numerous specialized problems arise which are not encountered in ordinary pumping operations of a different nature. For example, there are periods in the operation of an oil well pump during whi h .no iluid is in contact with either the polish rod or its packing and hence it is desirable to provide special equipment to lubricate and .cool these elements. Again, many of these specialized problems arise from the nature of the oil itself, which constitutes an ever-present fire hazard and which frequently contains microscopic sand as well as other deleterious materials of an abrasive or chemical nature which are extremely harmful to ordinary packings. Still another problem arises from the fact that the pump frequently must be located far down in the well, thus necessitating the use of unusually heavy machinery at the surface of the well for handling the polish rod and its associated parts. This ordinarily takes the form of a walking beam which in operation imposes a certain amount of sidewise motion or lateral thrust upon the polish rod packing.-

It is accordingly an important object of the present invention to provide an improved polish rod stuifing box assembly adapted to seal a well.- head casing and to accommodate slight relative lateral movements of a polish rod therein.

Another object of the invention is to provide a, polish rod stuffing box embodying a novel packing element having a particular structure and external shape which enable it to be repeatedly adjusted to maintain adequate, even pressure against the polish rod.

A further object is to provide a stuffing box and packing of the type described wherein necessary adjustments of the pressure of the pack,- ing element against the polish rod may be expeditiously accomplished by external means.

Another object of the invention is to provide a novel packing element having a variable Shape in cross section whereby it may be adjusted numerous time and still ma ntai a sa sfactory seal de e r ue t ri tion. or corrosion A still further object of the invention resides in the provision of an improved pa k ng file ment formed from a strip of alternate layer of fa ric and filaments which been molded mder heat and pressure into a unitary structure.

Still another object is to provide an improved stufiing box follower embodying a lubrication chamber comprising a spring-pressed wiper element and Spout structure for lubricating the polish rod and pack g and for reducing fire hazard.

The above as well as other and further objects and advantages of the present invention, together with a more complete understanding thereof, will become more readily apparent to one skilled in the art from a consideration of the following detailed pecification taken in conjunction with .the accompanying drawings wherer Fig. 1 is a front elevation of a stufiing box assembly in accordance with the present invention showing the parts in the relative positions which they occupy after considerable wear of the packins element has taken place;

Fig. 2 is a longitudinal sectional view to an enlarged scale of the stuffing box assembly of Fig. 1 but taken at right angle thereto and showing the parts in their relative positions prior to any substantial wear of the packing element;

Fig. 3 is a top plan view of the stufling box assembly, the rod being shown in section;

Fig. 4 is a transverse cross-sectional view through the follower taken substantially along the line 4-4 of Fig. 2;

Fig. .5 is a detailed cross-sectional view of the packing element forming an important part of the present invention;

Fig. 6 is a plan view of the spring for holding the wiper in position; and

Fig. '7 is a transverse cross-sectional view of the wiper element per se.

Referring to the drawings and particularly to Figs. 1 and 2 thereof, there is illustrated an improved stufiing box assembly in accordance with the present invention comprising a generally cupshaped housing It, a packing element II, and a generally cylindrical, hollow gland or follower P2. The housing I0 is apertured as indicated at H) and is provided with a depending skirt portion [4 adapted to be secured to the top of a well casing 15 as by means of threads IS. A polish rod i1 is shown fragmentarily in position in the stuifing box assembly and it will be understood that this polish rod H is adapted to reciprocate within the stufling box during operation of the pump.

As shown in Fig. l, the follower I2 is provided with a pair of ears l8 and I9 projecting laterally outwardly from its upper portion an i ing apertures near their outer ends for the reception of a pair of elongated bolts 2|] and 2|,

receive the lower ends of bolts 28 and 2| and are further provided with rectangular

shaped recesses

28 and 29 in their lower surfaces, re-- ceiving the square nuts 30-and 3| which.--are threaded on the bolts 20 and.. 2 |,,respectively The rectangular shaped recesses'28 and '29 are only slightly larger in one dimension than; the:

width of the nuts 30 and 3| and serve to prevent rotation of the latter upon the bolts 20 and 2| when the nuts are seated in said. recesses.

The follower I2 is providedat its bottom portion with a pair of horizontal shoulders 32 and 33 (Figure- 2) adapted to. abut against

similar shoulders

34 and 35 formed by acounterbore in the top portion of the packing element II, and an aperture 35 is formed centrally in the bottom of the follower |'2 for the pass-age of the polish rod l7 therethrough.

From the description thus far, it will be apparent that the two pairs of cars |5|9 and 2521 together with their associated nuts and bolts 2|l-2| and 353| serve to retain the components of the stuffing box in assembled relation, the packing element II and follower l2 being in nested relation within thehousing IE), and the

follower shoulders

32 and 33 bearing against the

packing element shoulders

34 and 35, This par-.

ticular relationship, of the parts is emphasized somewhat as it is through the proper spacing of the attaching ears and the use of elongated fastening means such as the bolts 20 and 2| that the stuffing box is enabled to efficiently absorb and withstand the wear produced by the relative lateral movement of the parts resulting from the sidewise movement of the polish rod caused by the conventional walking beam (not shown) As best shown in Figs. 2 and 5, the packing element H is novel both as regards its internal construction and its external configuration. This packing element comprises a series of alternate layersof resilient material 35, such: as synthetic rubber or the like, open mesh fabric, 36, and filaments 36" of cotton, rayon or the like formed by wrapping a ribbon of such materials in successive layers about a spindle and molding it into a unitary structure by the application of heat and pressure. The finished product, as indicated in the drawings, has a series of such filament layers extending diagonally downward towards the polish rod forming a wearing surface which is not easily broken down and which maintains a firm sealing surface 31 and sharp sealing lip or edge 38 despite wear and corrosion.

The body of the packing element comprises a downwardly and inwardly tapering upper portion 39 and a substantially hemispherically curved bottom 40, the housing I being similarly shaped for the reception of the packing element. As the packing element is compressed between the housing l0 and the follower l2, this tapering and rounded bottom shape results in maintaining an efiicient seal against the polish rod As wear of the packing element inevitably occurs, the seal is maintained by tightening the bolts 1!! and,

2| to press the packing element II more firmly into the housing l and, due to the shape of the element and the interior of the housing, efficient sealing may be maintained until the packing H has been largely used up, the internal construction of the packing element preventing its breakdown during this wearing process.

In order to lubricate the packing element and polish rod during operations when no oil from the well reaches them and in order to reduce the fire hazard which might be occasioned by slight leakage of oil along the polish rod at times when the packing element does not maintain a perfect seal, the follower I2 is provided with a lubri- :cating chamber 4| surrounding the polish rod l1.

As best shown in Figs. 3 and 4, the upper por- :tion of the follower I2 is formed with a plurality of spaced inwardly projecting upper and lower retaining lugs 42 and 43, respectively, between which an annular wiper element 44 of synthetic rubber or similar resilient material is maintained. The element 44 is retained against the polish rod I"! by means of a spring 45 engaged in a notch 46 formed in the outer periphery of the wiper element 44.

An aperture 41 is formed in the side wall of the follower l2 and opens into a trough-like spout 48 extending outwardly therefrom. The spout 48 has vertical side walls 49 and 5!) and an open end 5| for the discharge of oil therefrom. The floor of the spout 48 is formed at two

horizontal levels

52 and 53, the top level 52 being vertically lower than the top surface 54 of the lower retaining lugs 43; By this arrangement it is possible to supply lubricating fluid to the chamber 4| by admitting it to the lower spout level 53 so that it will drain into the chamber 4| rather than out the open end 5| of the spout. At the same time, it will be noted that the bottom edge of the wiper element 44 will at all times lie above the top floor level 52 of the spout and consequently above any fluid within the chamber 4|, so that any oil which has leaked pastthe packing element I into the chamber 4| cannot by-pass the wiper element 44 but will be stripped from the polish rod H and collected in the chamber 4| to be ultimately discharged through the open end 5| of the spout into a suitable receptacle.

For ease in assembling the stuffing box, the packing element may be provided with a diagonal split 55 and a similar split 56 typically may be formed in the wiper element 44. The wiper element 44 may be inserted through the aperture 41 and wrapped about the polish rod whereas the spring 45 may be inserted through an annular aperture 51 located in the top 01 the follower l2 and formed by cutting away a portion of the upper retaining lugs 42.

The operation of the apparatus will be more or less obvious from the foregoing description.- The tapered construction of the packing H and the corresponding shaping of the inner surface of the casing I0 is such that as wear occurs incident to reciprocation of the rod H, the packing l| tends to be moved bodily radially inwardly. Accordingly, throughout the life of one of the packings II, a snug fit thereof with the polish rod is constantly maintained. The fabrics and filaments embedded in the packing II, in combination with the sharp lower edge 38 of the packing, serves to wipe down the rod IT during each upward movement thereof. Accord-- ingly the passage of oil past the rod H is minimized.

The 20 .1 8. 20 and 2| have slight clearance inthe openings through which theypass, and since the lugs l8 and I9 are always substantially spaced above thelugs 26 and 21., a reasonable degree of lateral deflection of the packing ring 44 relative to the packing II is provided for. Even when the follower i2 is in its lowermost position as shown in Figure 1, with the packing I l substantially completely Worn, the length of the bolts 20 and 2| between the casing and follower is sufficient to permit the lateral movement referred to.

The reservoir 4| serves to maintain a body of lubricant above the packing H. Without this packing, or with an inefficient packing, an excessive amount of oil moves upwardly along the rod l1. Even with the most efficient packing, as in the present construction, some small quantity of oil finds its way above the packing. In the present construction, the reservoir 41 serves to contain this leakage oil to assist. in lubricating the rod l1.

Because of the extremely high efficiency of the present construction, particularly when the bolts 20 and 2! are maintained properly tight, insunicient oil for lubrication purposes sometimes finds its way into the chamber 4!. Addi tional oil may be added by pouring it onto the surface 53. Excessive oil cannot be maintained in the reservoir M, however, either by pouring oil thereinto in the manner stated or through the accumulation of leakage oil, since an excess of the lubricant will ove'rflow over the surface 52. The level of the lubricant accordingly will always be maintained below the bottom of the packing ring 44.

Iclaim:

1. A polish rod stuffing box comprising a generally cup-shaped apertured housing having a downwardly and inwardly tapering interior side wall terminating in a concave substantially hemtspherically curvedv bottom portion, a pair of apertured ears projecting laterally outward from said housing, an apertured resilient packing element in said housing having its outer surface shaped to conform to the interior wall of the latter and including a pair of horizontal shoulders formed in its top portion, a follower having its bottom portion shouldered to conform to the top portion of said packing element and adapted to abut against the latter, means forming a lu-- brication chamber within said follower including an outlet in the side wall thereof, a radially inwardly springpressed, annular wiper within said chamber above said outlet, a pair of apertured ears extending laterally outward from said follower, and fastening means operatively as sociated with both said pairs of ears for'adjusting the pressure exerted on said packing element by said housing and follower.

2. A polish rod stuffing box comprising a generally cup-shaped apertured housing having a downwardly and inwardly tapering interior side wall terminating in a concave substantially hemi-v spherically curved bottom portion, a'pair of apertured ears projecting laterally outward from said housing, an apertured resilient packing element in said housing having its outer surface shaped to conform to the interior wall of the latter, a follower having its bottom portion shaped to conform to the top portion of said packing element and adapted to abut against the latter, means forming a lubrication chain..- ber within said follower including anoutlet in the side wall thereof, an annular wiper within said chamber above said outlet, a pair of apertured ears extending laterally outward from said follower, and fastening means connected between said airs of ears for adjusting the pressures ert'ed on. said packing element by said housin and follower.

.3. A stuffing box comprising a generally cu shaped, apertured housing having a downwardly and inwardly tapering interior side wall tcrmie mating in a smoothly curved, substantially hemispherical bottom portion, said curved bottom p r on. lyin Wholly above a plane p rpendicular to the axis of said stuffing box and passing through the radially inner limits of said curved ot om portion, a pair of apertured ears projecting laterally outward from said housing, an apertured resilient packing element in said hous ing having its outer surface shaped to conform to. the. interior wall of the latter and including a pair of horizontal shoulders formed in its top portion and an intermediate portion tapered to decrease in diameter downwardly, a follower having its bottom portion shouldered to conform to the top portion of said packing element and adapted to abut against the latter, means forming a lubrication chamber within said follower including an outlet in the side wall thereof, a pair of apertured ears extending laterally outwardly from said follower, and fastening means connected between said pairs of ears for adjusting the pressure exerted on said packing element by said housing and follower.

4. A stuffing box comprising a housing having a downwardly and inwardly tapering interior side wall terminating in a concave smoothly curved bottom portion, said curved bottom portion lying wholly above a plane perp dic l r o the axis f said stuffin b x a passing throu h the radially inner limits of said curved bottom portion, a pair Of apertured ears projecting laterally outward from said housing, an apertured resilient packing element in said housing having its outer surface shaped to conform to the interior wall of the latter and including a pair of horizontal shoulders formed in its top poltion and an intermediate portion tapered to decrease in diameter downwardly, a follower havin its bott m p rt on sho l red to confor to the top p r n of said packing elemen and adapted to abut against the latter and to nest within said housing, means forming a lubrication chamber within said follower, a pair of ap ertured ears extending laterally outward from said follower, and fastening means connected between said pairs of ears for adjusting the pressure exerted on said packing element by said housing and follower.

5. A stuffing box comprising a housing having a downwardly and inwardly tapering interior side wall terminating in a smoothly curved bottom portion, said curved bottom portion lying wholly above a plane perpendicular to the axis of said stuffing box and passing through the radially inner limits of said curved bottom portion, an

1 annular packing element in said housing, the

outer surface of which conforms to the shape of said interior housing wall, and the top portion of includes a pair of horizontal shoulders and an intermediate portion tapered to decrease in diameter downwardly, a follower having its bottom portion shouldered to come form to the top portion of said packing element and adapted to abut against the latter andto nest within said housing, and fastening means 7.5 interconnecting said housing and said follower and adjustable to control the amount of pressure exerted on said packing element.

6. In a polish rod stuifing box, a packing follower comprising a generally cylindrical, hollow body having a lubrication chamber formed therein and top and bottom central apertures for the passage of a polish rod therethrough, a pair of apertured attaching ears extending laterally outwardly at opposite sides of the top portion of said body, a plurality of spaced upper and lower retaining lugs projecting radially inwardly into the upper portion of said chamber, an annular radially inwardly spring-pressed wiper element in said chamber between said upper and lower lugs, the side wall of said body having an aperture adjacent said lower lugs, and a spout extending outwardly from said last mentioned aperture having its trough floor at two levels, the top level being lower than the upper surface of said lower lugs.

7. In a polish rod stufiing box, a packing follower comprising a hollow body having a lubrication chamber formed therein and top and bottom central apertures for the passage of a polish rod therethrough, a plurality of spaced upper and lower retaining lugs projecting radially inwardly into the upper portion of said chamber, an annular radially inwardly spring-pressed wiper element in said chamber between said upper and lower lugs, the side wall of said body having an aperture adjacent said lower lugs, and a spout extending outwardly from said last mentioned aperture and having its trough floor at two levels, the top level being lower than the upper surface of said lower lugs.

.8. In a stufiing box, a packing follower comprising a hollow body having a lubrication chamber formed therein, a plurality of spaced upper and lower retaining lugs projecting radially inwardly into the upper portion of said chamber, an annular wiper element in said chamber between said upper and lower lugs, the side wall of said body having an aperture adjacent said lower lugs, and a spout extending outwardly from said last mentioned aperture and having its trough floor at two levels, the top level being lower than the upper surface of said lower lugs.

9. A stuffing box comprising a housing having its interior side wall tapering downwardly and inwardly and terminating in a smoothly curved bottom portion, an annular packing element in said housing, the outer surface of which conforms to the shape of said interior housing wall, a follower adapted to abut against said packing element and to nest within said housing, said packing element comprising a plurality of layers of filaments embedded in a resilient material and extending diagonally downward from said outer surface toward the center thereof at a greater angle to the vertical than the taper of said side wall.

10. A stufiing box comprising a housing having an interior side wall portion tapering to decrease in diameter downwardly and terminating in a smoothly radially inwardly and downwardly curving bottom portion, said curved bottom portion lying wholly above a plane perpendicular to the axis of the stufling box and coincident with the radially inner limits of said curved bottom portion, an annular packing element in said housing, said packing element having its outer surface conforming in shape to said interior housing wall, said packing element having embedded therein layers of elasticity-reducing material, said layers being conical and tapering downwardly and inwardly at a sharper angle than the taper of said housing side wall portion, and a follower adapted to abut the top of said packing element to force it relatively downwardly.

11. A stuffing box constructed in accordance with claim 10 wherein said layers of material are alternately filaments and fabric.

12. A stuiiing box comprising a housing having an interior side wall portion tapering to decrease in diameter downwardly and terminating in a smoothly radially inwardly and downwardly curved bottom portion, said curved bottom portion lying wholly above a plane perpendicular to the axis of the stuifing box and coincident with the radially inner limits of said, curved bottom portion, an annular packing element in said housing, said packing element having its outer surface conforming in shape to said interior housing wall, said packing element having embedded therein layers of elasticity-reducing material, said layers being conical and tapering downwardly and inwardly at a sharper angle than the taper of said housing side wall portion, and a follower having its longer end adapted to abut said packing element, the lower end portion of said follower having a surface generally perpendicular to the axis of the said packing element and a surface tapering to decrease indiameter downwardly, the upper end of said packing element having portions corresponding in shape to and engaging said lower end surfaces of said follower to exert downwardly and radially outward forces against the upper end portion of said packing element.

13. A stuffing box for a rod comprising a housing having an interior side wall portion tapering to decrease in diameter toward one end of the housing and terminating in a smoothly curved portion formed substantially accurately as a section of a sphere, said end of said housing having an opening through which the rod projects and such opening being of larger diameter than the rod, a packing element corresponding generally in external shape to the interior wall of said housing and arranged therein, and a follower connected to said housing and arranged at the other end thereof and having an end engaging said packing element, said follower hav- -ing an opening through which said rod extends and such opening being of larger diameter than the rod, said end of said follower having a s'houlder engaging a portion of said packing element to transmit direct axial movement thereto and having a portion tapered to decrease in diameter toward said first-named end of said housing and engaging a portion of said packing element to exert radially outward forces on the adjacent portion of said packing element while said shoulder exerts endwise force thereagainst, said packing element having an opening therethrough corresponding in size to the rod snugly to fit the latter and the portions of the upper end of said packing element which are engaged by said follower corresponding in shape to the follower surfaces which they engage.

14. A stuffing box constructed in accordance with claim 13 wherein said packing element has imbedded therein layers of elasticity-reducing material, such layers of material being conical and tapering to decrease in diameter toward said first-named end of said housing at an angle sharper than said tapered wall portion of said housing.

15. A stuffing box packing element comprising 9 a resilient annular body having a longitudinal aperture therethrough of substantially uniform cross-section and including a downwardly and inwardly tapering exterior surface terminating in a convex smoothly curved bottom portion, said body comprising alternate layers of fabric and filaments embedded ina resilient material.

HAROLD CALLAHAN.

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

UNITED STATES PATENTS Number Name Date 24,569 Burney June 28, 1859 128,906 Reed July 9,1872

Number Number 15 60,525 103,250

Name Date Myers May 25, 1875 Hewitt June 3, 1879 Dods Mar. 15, 1898 Dresser May 16, 1899 Oehlschlaeger Oct. 31, 1905 Gates Feb. 6, 1923 Wigle May 10, 1927 Kahle May 6, 1930 Fuller et al July 26, 1932 Stone June 23, 1942 FOREIGN PATENTS Country Date France of 1863 Sweden of 1941