US2235289A - Stuffing box - Google Patents

Description

Y March 18, 1941. 1. l.. DUNN ET AL sTUF'F'ING Box 5 sheets-*sheet 1 Filed July 26, 1937 .iLlI l al U a ma n, 2

March 18, 1941.

l. L. DUNN ETAL STUFFING BOX Filed July 26,' 1957 um VENTQRS /rw/n l.. Dunn,

Haro/d 5T Cfr-aok?. and BJYames 0. Lew/s.

5 Sheets-Sheet Patented Mar. 18, ldi

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STUFFWG BOX Application July 26, 1937, Serial No. 155,640-

i'caim. l (el. 28s-si) This invention relates to stuiling boxes for the pumping rods of oil and like Wells, and more particularly to astulng box capable of iiexibly sealing olf the upper working end of the well pumping rods from the well.

In pumping oil wells, it is the usualpractice to provide a pump element near the bottom of the well hole and to actuate the pump element through a. string of rods, the upper end of which is ordinarily provided with a polish rod passing through a stuing box above the head of the well for sealing oif the oil or other fluids, which are being pumped from the well. The polish rod is usually operated by a walking` beam, pumping jack, or other apparatus suitable for reciproeating the rods in the well for withdrawing well fluids from the well by the pump element during such reciprocation of the rods. `The polish `rod has imparted to it an arcuate motion dueto the customary arcuate reciprocatory motion of the rod reciprocating mechanism. The result of this use considerable pressure onthe packing, causp' ing it to be subjected tol a great deal' of friction. When the well is being pumped without lubrication by the Well fluids, as for example, when the gas pressure in the well causes the oil, which has been pumped into the tubing, to' flow from and empty the tubing, theI packing can receive no additional lubrication until the pump has raised' oil to the top ofthe well. This is also true whenl 40 an old well is being periodically pumped and before the well tubing can be lled with well fluids to lubricate the stuiiing box. This makes the rods more dificultto operate, slows the drop on the return stroke, causes burning out of the packing in the stuiling box and necessitates relining the stuiiingbox with fresh packing with the consequent expense oi' the packing, together with the loss of time in reinstalling the packing and stuffing box.

It is, therefore, the principal object of the present invention to provide a stuiiing box, which will permit the polish rod to have appreciable lateral. movements imparted to it and automatically adjust the sealing packing of the stuiling box to the misaligmnent of the polish rod with the axis of the well without increase of the packing pressure on the rods, and which operates -eiiiciently under such eccentric conditions of the polish rod relative to the axis of the well.

, Other important objects of the present inven- 5 tion are to provide a stuffing box with a resilient packing having no initial pressure and that is self-packing under the well pressure, that re- .lieves the pressure on the rods ontheir return stroke to permit easy dropping of the rods, that w reduces friction between the polish rod and stuifing box to a minimum, thatwill not burn out when operating with fluid flowing from the well, and which, because of these features, materially reduces the cost of pumping va well. l5

It is a further object of our invention to provide a stuiling box which iiexes in conformity to the normal arcuate movement of the polish rod operating therethrough to thereby reduce the tendency of the packing in the stufng -box to y20` wear out and become loosened.

In accomplishing theseand other objects of the present invention, We have provided improved details of structure, the preferred forms of which are illustrated in the accompanying 25 drawings, wherein:

Fig. 1 is an outside perspective view of a stuffing box embodying the features of the present invention, the stuffing box being shown'in assembled lcondition on the head of a well tubing. 30 I Fig. 5 is a horizontal cross-section on the line i ..5-5, Fig. 2. l

Fig. 6 is a perspective View of the preferred 45 l form of packing used in the stuiiing box.

preferred form offstuffingbox, illustrating 'its ap'- plication to the head 'of a well by a 'flexible jointure embodying features of the present invention.v 55

well.

Fig. 10 is a vertical cross-section through a modified form of box embodying the features of our invention and illustrating a modified form of flexible jointure therefor with the head of a well.

Fig.v 11 is a horizontal cross-section on the line II-I I,Fig. 10.

Fig. 12 is a vertical cross-section through a stufiing box and head of a well, illustrating/a flexible ball and socket jointure therebetween Fig. 13 is a horizontal section on the line |3-I3, Fig. 12.

Referring more in detail to the drawings:

In Figs. 1 to 6, inclusive, we have shown the preferred form of stufiing box which, as in ordinary practice, is mounted at the upper end of a T-fitting I, which is suitably mounted at the upper extremity of tubing 21 leading from an oil well or the like (not shown) and which is provided in` its side opening 3 with a well fluid lead line'4 for dissipating iuids pumped from the 'I'he stuiiing box is generally designated 5 and consists of a cylindrical body member 6 having threaded engagement 1 at its lower outer end with the upper opening of the T-ftting I. The

body member 6 is provided Iwith an axial bore 8,

the upper portion of which bore is countered, as at 9, to provide an annular'shoulder I0. An annular recess II is also provided at the shoulder,l which is of larger diameterthan the counterbore 9. Seated on the shoulder I is a preferably metallic retaining ring I2, having an outer diameter less than the diameter of the counterbore 9, so it is insertable into the body through said bore. However, the ring is of greater diameter than the axial-bore 8, and is thus adapted for seating engagement on the shoulder- I0 and for limited lateral reciprocatlon in the recess in response to the customary arcuate movement of l a polishrod I3 which, as in customary practice, is mounted on the piunping rods in the tubing 2 and extends therefrom upwardly and outwardly for suitable connection with a walking beam (not shown) or other suitable apparatus for reciprocating the rods in the tubing to pump the well with a pumping element (not shown) on the lower end of pump rods in the usual manner.

Mounted in the counter-bore 9 and seatingon the retaining 'ring I2 is a plurality of invertedl U-shaped flexible packing rings I4', as particularly shown in Fig. 6. The packing rings I4 are formed of a suitable toughresilient composition and have inner and outer oppositely outwardly tapered downwardly extending walls I5 and I6, each of which are joined at their upper ends by a substantially bevelled top walll I1, the top walls I I of lthe packing rings being respectively engageable between the walls of superimposed packing rings, asshown in Figs. 2 Vand 3, in such a manner that a compact packing is provided in the stufling box of any desirable length 'or thickness. The packing rings are preferably of a collective thickness vless than the distance between the retaining rings when in lowered'position, so that a iloating or sh gill motion is imparted thereto in response to pumping'of the well. The bottom retaining ring is also provided with a hole I2 for the passage of well mosphere, the packing rings collapse and friction is thus reduced. v

'I'he upper end of the stuilng box body member 6 is provided with external threads for receiving the lower internally threaded end I8 of a cap member I9, the cap member I9 being provided with ribs or the like' 28 to facilitate its application to the body member 6 and also being provided with an internal horizontal dividing wall 2|, the lower face of which is spaced from the lower end 22 of the cap a suicient distance to provide a pocket or space 23 between said lower face and the upper horizontal end 24 of the body member 6. A retaining ring 25 is mounted on the polish rod I3 within the pocket 23, the ring 25 having av smaller outer diameter than the 1 inner diameter of the threaded lower end of thecap 'member and the ring 25 is of less thickness than the depth of the pocket, lateral and vertical movements of the ring thus being permitted with'in the pocket whenlateral thrusts are imparted to the polish rod during its reciprocation. The retaining ring 25 is adapted to rest on the upper end 24 of the body member 6. Axial bores 26 and 21 are provided in the horizontal wall 2| and upper cap end 28 of the cap member which are of larger diameter than the diameter of the polish rod, so that lateral play of the polish rod will not bind or strike the end and dividing walls of the cap member. 'I'he space 29 between the wall 2I andend 28 of the cap member provides a reservoir at` the upper end of the cap member, which is suitable for the reception of oil or other lubricating medium to maintain the packing4 rings and polish rod in lubricated condition for facilitating operation oi?4 the well when no fluids are flowingvfrom the wel itself to lubricate the stuiling box and polish ro In the operation of -a wellprovided with a. stuffing box embodying the features of the present invention, well pressure ordinarily causes uid from the well to be forced .upwardly past the in effect, float, which has the advantage of reducing the bind'and wear ordinarily encountered in stuffing boxes.

As the polish rod is reciprocated by means of a walking beam, for example, lateral play is ordinarily imparted to it which, when transmitted to the packing, has no deleterious eifects on the stuiling box due to the fact that the retaining rings may follow or correspond to the play of the polish rod in the counter-bore and space 23 and, further, due to the fact, as particularly shown in Fig. 3, 'thatthe packing rings 'are either compressed or expanded at opposite sides thereof, depending upon the direction of lateral play of the polish rod, the packing rings always' maintaining 'a seal between the stuiiing box and polish rod to thus eiectively prevent escape of well vuids from the well.

Even should pressure in the Well be insufficient to lubricate the-stuffing box and polish rodwith well fluid, lubricating medium may be deposited in the reservoir 29 for gravitational application to the packing rings. It sometimes happens that small quantities of lubricant are ex-` trude'd through the packing rings into the reservoir, 'in which event such fluid will gravitate back down over the packing'rings tol maintain them in lubricated condition, when the well is pumping dry.

In the event that the well is operating in a dry state, the resiliency of the packing members and the lateral play permitted by the retaining rings reduces the bind between the stuffing box and the polish rod and the packing members will, therefore, not burn out, since there (is not an excess of friction., i

In Figs. 'l and 8, we have shown a modified form of packing, wherein the cylindrical body member 30 of a stui'lng box is provided with a counter-bore 3| to provide a shoulder 32 in the' interior of the member 30 for seating a retaining ring 33, the retaining ring 33 having an axial-bore 34 of substantially larger diameter'v each series of rings has inner and outer diam- -ing action is permitted when the polish eters of diiierential size. The series of superimposed packing rings 36 have inner diameters of substantially the same diameter as the polish rod, which adapts them 'for engagement therewith and the outer series of packing rings 31 have an outer diameter substantially the same as the counter-bore 3|. The series of rings are separated by a cylindrical sleeve 3B mounted therebetween and seated on the retaining `ring 33, it being apparent that the amount of lateral play between the polish rod 35 and the stufiing box body member 30 is vsubstantially doubled over l that provided in our preferred form of invention,

which is due to the greater amount of ex inherent in the multiple series of packing rings.

The upper end of the member 3@ is provided with external threads for receiving the internal threads at the lower end of the cap member 39, the cap member being of substantially the same Vconstruction as the cap member i9, previously bounded by the walls 4| of the cap member.

A retaining ring 43 is also provided, which has an axial-bore of approximately the diameter of the polish rod and an outer diameter less than `the inner diameter of the end of the cap member, but'of greater diameter than the counterbore 3l, thus adapting the retaining ring 43 for seating on the upper end of the member 30 and on the' upper end of the cylindrical sleeve 33, when-in normal condition; The ring 43 is of less thickness, however, than the space v44 between the upper end of the member 30 and the lower face 45 of the dividing walls 4|, `so that a float.- rod is reciprocated in the stufng box.

In this construction, it is apparent that when the well is being pumped, well uids are forced to the upper end of the well for transmission through the space between the retaining ring 33 and the polish rod for expanding the packing rings to seal oil the topof the well. It is also apparent that lateral thrusts may be imparted to the polish rod, in which event the polish rodvis not bound by the ring 33, due to the space theret flange 65.

between, nor is it bound by the upper end of the cap member due to the play permitted by thel retaining'ring 43 in the space 44. Downward movement of the polish rod compresses the packing rings to increase their respective inner diameters, in such a manner that friction is reduced therebetween and burning out of the packing rings is precluded. Further, since a multiple se-f ries ofV packing rings `is provided, thev possible expansion and contraction of the stuiling box packing is substantially doubled over that of a single series of rings and flexibility of the stuing box is, therefore, materially enhanced.

l In pumping wells with a long stroke, the arcuate and lateral motions of the rods are more pronounced. It is, therefore, sometimes necessary to -provide greater flexibility of the stung box relative ytothe rods and, in Fig. 9, we have shown a modified form of the invention, wherein a stuiiing box 46, embodying the features of the preferred form of invention, is mounted on the usual T- tting 41 at the upper end of a well, but which is interconnected therewith by a flexible coupling '48 to compensate for such deflection of the rods from the axis of the well.

The flexible coupling consists of a nipple 49,' having its lower end externally threaded for engagement in the T-fltting 41 and having an anwhich is formed of a material resistant to well Wires or the like 55 are provided on the outer surface adjacent the ends of the body memfluids.

ber 54 for enhancing the binding action of the body member between a threaded coupling 56 secured thereon and the end 5| of the nipple when it is screw-threadedly engaged with the nipple.

.The upper end 51 of the flexible member 54 is of -a construction substantially similar to its opposite endyjust described, with the exception that the retaining sleeve r58 thereof is' spot welded, or

. otherwise suitably secured, to the lower, inner end of the axial-bore 53 of the stuf'iing box, the attachment of the member 54 to the stufdng box being had through threaded engagement of the lower end of the stuillng box with the coupling 60 mounted on the member 54,- as shown at 6I.

, In operating a well-by pumping rods having their upper end extending through a stufng box and exible coupling of the character just de.- scribed, 'it is apparent that lateral play of the polish rod is compensated for by the stuffing box as pointed out in lconnection with the preferred form of invention, and that such lateral play is further absorbed by the coupling, since it has a tendency to bend'in the direction of thrust of the polish rod. Flexibility of the well head connection and seal is thus greatly enhanced, which .prolongs the life of both the stung box and pumping equipment and also increases the output of the well by reducing the necessity for shut-downs.

In Fig. 10 is illustrated the upper end of a well tubing 62, having a T-tting 6 3 .mounted thereon provided with an outlet 64 in a wall thereof for testing the well,v the T-fitting being provided at its upper end with a laterally extending The bore 66 of the T-tting ls ared outwardly at its upper end, as shown at 61, land olset as at 68 to provide a shoulder 69 for seating a flexible ring 10 having a central bore 1| of substantially larger diameter than the diameter oi' y the polish rod 12, which is reciprocable thereothrough. The ends of the flange 65 are provided with bores for receiving suitable fastening devices as at 95, for seating engagement on the curved 13, which are insertable therethrough and through corresponding aligned bores 1I of a clamping member 15, which is adapted to seat on the ange 65. The clamping member is provided with a central opening 16, the lower end of which is b'evelled outwardly, as shown -at"11, to form a seat for the rounded lower end 18 of a stuiilng box 19.- The stuffing box 19 is provided with an extended lower end 80, the outer periphery of which is provided with an annular ilange 8| which'forms a shoulder for seating an inverted U-shaped flexible'packing ring 82, said shoulder forming one side of the iiange and the rounded upper end 18 which seats in the curved bore 11 of the clamping member forming the other side-of the flange. The packing ring 82 is of less thickness than the distance between the flange 8l and the upper face .83 ofthe resilient ring 10, whereby well fluids issuing from the well, when it is in operation, are transmitted to the under face thereof under pressure for expanding same to create a seal for packing off the well at the head thereof.

In the operation of a well to which the present form of invention has been applied, it is apparent that lateral thrusts on the polish rod will not only be absorbed by the stuiling box 19,I but play is also permitted between the lower end of the stumng box'and the flanges at the upper end of the T-fitting, thus materially reducing wear and tear both on the polish rod and well equipment and at the same time maintaining an effective seal for packing oiI well uids.

vIn Fig. 12 we have provided a further modified form of invention wherein the usual T-tting 84 of exible character and of inverted U-shape has its ends 9| seated on the' shoulder and respectively engageable with the nipple and with theside face 92 of the flanged lower end 93 of the stuffing box body member 94. The flanged end 93 of the stuing box is curved on its lower end,

inset surface 81 of the nipple. Mounted in the upper end of the nipple and adapted for threaded interengagement therewith is a retaining mem.- ber 96 having* its upper, outer face 91 in align.- ment with the side face of the nipple and having a tapered central bore 98, the taper thereof being in an upward, outward direction.

The principal advantages in the forms of invention embodying our improved features are that the cost of maintenance of an oil well is appreciably reduced, due to the fact that the packing rings are protected from an excess of friction, which precludes-their burning out and avoids the consequent necessity of stopping the .well to replace the packing and also saves the cost of the packing. Further, since there is no bind between the polish rod and the well head, power required to operate the well is decreased and the life of the equipment prolonged, due to the lack of wear on the stuffing boxl well head and rods. An effective seal is, further, provided for maintaining sealing contact between the stufling box and polish rod, which prevents loss of well fluids, whether the stuffing box be in a Wet or dry condition.

What we claim and desire to secure by Letters Patent is:

A stufilng box including a hollow body member having an oil'set bore, and a counter-bore, packing rings mounted in said offset bore engageable with a member reciprocably mounted in the body member, a retaining ring movably mounted in the counter-bore and adapted to seat said packing rings, and a retaining ring movably mounted in the body member in spaced relation to the first named retaining'ring and in engagement with the uppermostpacking ring for limiting movement of thepacking rings in one direction.v

IRWIN L. DUNN.'

HAROLD S. CROOKS. JAMES O. LEWIS.

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