US2567479A - Polish rod stuffing box - Google Patents

Description

SCP 11, 1951 G. G. HEBARD 2,567,479

POLISH ROD STUFFING BOX ATTORNEYS sept. 11, 1951 Filed Sept. 8, 1947 G. G. HEBARD POLISH ROD STUFFING BOX 2 Sheets-Sheet 2 INVENTOR. G.G. HEBARD A T TORNEKS Patented Sept. 11, 1951 POLISH ROD STUFFING BOX Glen G. Hebard, Bartlesville, Okla.. assignor to Phillips Petroleum Company, a corporation o! Delaware Application September 8, 1947, Serial No. 772,789

Claims. (Cl. 286-16) This invention relates to polish rod stuffing boxes. In one specific aspect it relates to a stuffing box for a polish rod in an oil well pump sucker rod line. In another speciilc aspect it relates to a polish rod stuffing box in which lubricant under spring pressure, and/or well pressure is applied to the packing.

In the art of polish rod stuiing boxes about 33 per cent of the causes of leaking are due to the man in charge of the pumps tightening the main packing of every stuffing box every time he passes the same which soon ruins the stuffing box, about 33 per cent of the cause of leaking is due to misalignment and inability of the stuffing box to adjust itself to the misaligned polish rod and about 33 per cent of the leaks are due to sudden changes of pressure in the well due to the well heading up and starting to iiow while being pumped.

It is an object of this invention to provide a stuiing box in which the main packing is maintained at a substantially constant predetermined tightness by spring means which cannot be tightened by the operator. H

Another object is to provide a stuiiing box which permits the main'packing and main packing glands to always align itself with the rod during such portions ot the pumping stroke when the rod is misaligned.

',Another object is to provide a stuffing box in which the pressure above the main packing may be maintained at substantially greater pressure than the pressure in the well during times when the well heads up and starts to iiow.

Stillfurther objects are to provide a stuffing box having a V type packing as the main packing with means to provide grease under pressure at all times on the packing, and in which a V type packing ring is reversed and used as a grease wiping ring to prevent excessive use of grease.

Other objects are to provide a stuing box capable of withstanding high well head pressures, whichis not dependent uponV well fluid for lubrication, and which is simple and rugged in construction, simple in assembly and adjustment, and generally better in operating characteristics, maintenance, cost of construction and which is foolproof.

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

In the drawings:

Figure 1 is an elevational view with a quarter 2 cross section of a polish rod stuiing box embodying the present invention. l

Figure 2 is an elevational view with parts broken away to show details of `construction of a Well tubing head and flow line provided with a polish rod stuiing box and lubricant supply neans for the same embodying the present invenion.

Figure 3 is an elevational view of a check valve seating for grease which'may be substituted for the similar seating shown in Figure 2 when desired.

In Figure 1 a polish rod stuiiing box is shown having a bowl generally designated as 3 provided with a cap generally designated as 4. While bowl 3 can be'made in a single piece it is desirable in some instances to make the same in several parts as shown. When made in several parts bowl 3 comprises a bowl base 6 having external threads l for attachment to the usual well tubing head. Obviously other attaching means, such as a bolted ange. can` be substituted in place oi thread 1 it desired. Bowl base 6 is provided with a shoulder 8 for receiving a bushing guide 9.

Securedto bowl base 6, preferably by welding at I I, is a cylindrical bowl body member I2 which is provided at its top with any suitable means for securing cap 4. However, it is preferable to use a vflange I3 provided with onlyy two bolt holes I4 and secured to I2 by welds I6 and I1.

Cap 4 can be made in single piece but preferably consists of a grease reservoir member I3 to which cap flange I9 is securedby welding at 2l. Obviously ange I9 has holes 22 corresponding to holes I4 so that cap 4 may be secured to bowl 3 by only two bolts 23 and nuts 24. Suitable washers 25 may be 'provided to aid in assembly and operation.

Cap 4 contains a grease reservoir chamber 26 and part I8 is provided with a stuffing box 2l having the usual follower 28 and bolts 29 to adjust the follower.v A suitable grease seal ring 3l is provided of suitable packing material for engaging polish rod 32 and preventing loss of grease from chamber 26 up the surface of rod 32.

The main packing gland 33 of the bowl 3 is mounted on a resilient seating ring 34 and its upper end is guided in cylindrical recess 36 of iiange I9. Bolts 23 are considerably smaller in diameter than holes I4 and 22 which allows movement of the upper end of gland 33 andilange I9 in a direction normal to the longitudinal axis of rod 32, and this movement is controlled and limited by an upper alignment ring 31 made ot of the same broken away to show the parts in u resilient material. In order to further alignand assure cushion the main packing gland 33 and to maintain the space between seating ring 34 and upper alignment ring 31 a number of auxiliary align-A ment rings 33 are preferably provided. By employing rings 33 spaces 33 are left which are just the right size to provide room for deformation and flow of resilient members 34, 31, and 33. which is an important feature of one preferred form of the present invention.

The main packing comprises one or more inverted V type packing rings 4I which ring or rings 4| are supported against an upper follower ring 42 by means of a loading spring 43 acting through lower following ring 44. It is preferred to also employ a V type packing ring 43 to act as a grease wiping ring to prevent excessive loss of grease. Grease wiping ring 43 is in reversed position to packing rings 4I and is spaced therefrom by spacer ring 41.

While not essential it is preferred to insure that spring 43 is kept out of contact with rod 32 by means of a guide ring 43 which may be provided with a positioning flange 43 preferably located at its lower end.

Access to chamber 23 is provided by a suitable grease hole and grease nipple 3l which is shown in Figure 2, and the discussion of the drawing will now proceed with reference to Figure 2.

In Figure 2 an oil, gas or other well generally designated as 32 is provided with a tubing 33 through which oil or other liquid is being pumped and/or flows under its own pressure. In order to operate a pump (not shown) located in the lower portion of tubing 53 (not shown) a string of sucker rods is provided (not shown) and attached to the string of sucker rods is a polish rod 32 which extends in the usual manner through stuifing box 3 and cap 4. Polish rod 32 has a polished metal surface, or substantially smooth metal surface, in order to reduce to a minimum the friction on packing 4| and any tendency of the rod to tear the packing to pieces.

Tubing 33 is provided with a tubing tee 34 to which stuffing box 3 is attached by threads 1 or other connecting means. Tubing tee 34 has a flow line nipple 33 to which the usual flow line 31 may be attached to carry the pumped and/or owing oils to suitable tanks (not shown).

In order to provide grease for grease reservoir 23 it is often sumcient to merely supply a check valve fitting 33 as shown in Figure 3 which may be substituted in place of connection 3| of Figure 2. In such a case a'portable grease gun is attached to bosses 33 of fitting 33 and the grease is forced through center passage 3| forcing the spring seated check valve (not shown) in the usual grease fitting 33 to open and allow the grease to pass into chamber 23. The portable grease gun (not shown) is then removed and the spring sets the check valve preventing grease from leaving chamber 23. l l

While that construction is suiiicient in many instances it is preferred to employ the permanently attached grease gun generally designated as 32 as connected in Figure 2 especially when weil 32 is one which heads up and flows intermittently during the pumping operation.

Grcasegunnconsistsofabodywhichcan be supported in any manner adjacent cap 4 but which is preferably secured to bowl 3 by strap 34 and bolt and nut 33 or other suitable securing means.

Body 33 contains a load of grease 31 which is being urged upwardly by piston 33 provided with suitable() typepacking 33 inpackingringgroove 1|. Piston 33 is urged upwardly by helical compression spring 12 pressing against cap 13. Cap 13 is secured to body 33 by any suitable means such as threads. Piston 33 is provided with a measuring rod 14 which extends down below cap 13 and indicates the amount of grease 31 remaining above piston 33.

Cap 13 is preferably provided with two openings leading from the outside into chamber 13, one of said openings passing through pipe 11 controlled by valve 18 to the atmosphere, and the other of said openings passing through pipe 13 controlled by valve 3i to the interior 32 of flow line 31.

In order to charge body 33 with grease 31 any of the usual type high pressure grease fittings on the market which contain a spring pressed check valve may be employed such as the type shown in Figure 3 which has bosses 53 or the type shown at 33 of Figure 2 which relies on pressure to keep the grease supply device (not shown) in alignment during the grease filling operation. Because of the spring check valve (inside of 33) it is possible to force grease into opening 34 on the top of 33 through a passage into chamber 33 but the grease cannot return because of the check valve. Fittings 33 and 53 are so common and well known in high pressure grease lubrication of automobiles and the like that further illustration is believed unnecessary. Among the trade names for such fittings are Alemite and Zerk.

Fitting 33 is connected to cylinder 33 by a T fitting 33 which has a branch leading to a pipe 31 which is connected to space 23 by fitting 3| in the side of cap 4.

In order to unload the grease 31 from the body 33 an emergency unloading valve 33 may be provided. However, valve 33 is unnecessary to the usual operation of the device.

Operation In the operation of the device rod 32 is reciprocated along its longitudinal axis by a walking beam, rod jack, or other mechanical movement (not shown) which device generally causes misalignment of rod 32 at some portion of the stroke. When such misalignment occurs the main packing 4I does not have to adjust for the misalignment as instead the main packing gland 33 compresses and deforms rings 34, 31 and 33 to keep packing 3 I, 4 I and 43 properly aligned with rod 32.

In such movement spaces 33 allow freely floating movement of cap 4 and gland 33.

If the well heads up and flows liquid under pressure it cannot pass up the surface of rod 32 because of V type packing ring or rings 4I. Lubrication of all the packlngs is provided by grease in chamber 23 which can freely pass as far up as packing 3i and as far down as 4I or 43. Packing 43 prevents excessive loss of grease down the rod.

Spring 43 provides the proper loading pressure on packing 4I and 43 and this pressure cannot be adjusted by the operator, which is important as the operator tends to tighten stuffing boxes too often.

In Figure 2 grease is inserted through opening 34, fitting 33 and T 33 to fill body 33 against the pressure of spring 12. Spring 12 then urges piston 33 to force grease 31 through pipes 33 and 3l into space 23 of cap 4.

Valve n is only used when it is desiredv to remove grease from 33 before disconnecting the device which prevents grease from squirting out of 5I when the same is disconnected.

assure If valve 8| is closed and valve 18 is open the pressure4 on grease 61 will be merely that of spring 12 and the atmosphere but if valve 18 is closed and valve 8| is open the pressure on grease 61 will be that ofi-.spring 12 plus the pressure in space 82 which is that of the well. In the well which heads and flows at a varying pressure it is often desirable to have the same pressure applied through pipe 19 to space 16 and transmitted to grease 61 so that the pressure above packing 4I will be substantially balanced with the pressure below the same with an excess pressure above packing 4| caused by spring 12.

At other times such balancing of pressureis unnecessary in which case valve 8| may be closedand valve 18 opened so that spring 12 is the main pressureon grease 61. While not critical it is preferred to have spring 12 provide a pressure of to 30 pounds per square inch when compressed and when substantially completely expanded spring 12 should still provide from 2 to 3 pounds per square inch pressure on grease 61.

In many installations it is unnecessary to have a permanent grease supply 62. In such cases a grease pressure fitting 58, as shown in Figure 3, may be substituted for 5|, 81, 62 and related parts of Figure 2 in which case grease is placed in space 26 of cap 4 through fitting 58 under pressure from time to time. As the permanent supply of 62 of Figure 2 operates automatically over a long period of time it is preferred.

The term tubing head in the claims is defined as meaning any upper portion of the tubing, or flow line connected thereto.

It is impossible for a workman to change the adjustment of or tighten the main packing 4|, which is therefore always in condition to stop any flow of well fluid, either gas or liquid. The work,- man can tighten stuiling box 28, 29, but this is a simple single solid ring packing which is merely a wiper and which is not delicate in adjustment as 4| is. Improper tightening of 28, 29 does little,

lif any, damage, but tightening 4| would be likely to result in great loss if the well starts flowing and packer 4| fails through excessive tightening and resultant wear.

Various materials of construction may be employed, however, it is preferred to make all the parts of metal except rings 3|, 34, 31, 38, 4| and 46. Of these rings 34, 31, and 38 are preferably made of rubber (either natural or synthetic) or some similar resilient material. Rings 3|, 4| and 46 are preferably made of some suitable packing material such as fiber, rubber (either natural or synthetic) felt or the like. While various metals may be employed parts 3 and 4 are preferably made of welded steel parts as shown or of cast steel or cast iron. While ferrous metals can be employed parts 28, 42, 41, 44, 48 and 9 are preferably made of bronze and while spring 43 may be made of any resilient material such as steel it is preferred to use Phosphor bronze because of its corrosion resistance.

While I have shown in the drawings, several particular illustrative forms of my invention, various modifications may be made in the same and in the various features of construction. without materially changing the invention therein, and formal changes may be made in the specific embodiment of the invention described without departing from the `spirit or substance of the broad invention, the scope of which is commensurate with the appended claims.

Having described my invention I claim:

l. A polish rod stuffing box comprising in combination a housing adapted to be secured to an oil Well tubing T, upper and lower resilient rings inside said housing, a stuiiing box of smaller diameter than said housing supported coaxially inside said housing by said resilient rings. packing inside said stufng box comprising, in combination, a spacer ring, at least one ring of the upright V- type packing below and at least one ring of the inverted V-type packing above said spacer ring, an upper follower ring above said packing, a lower follower ring below said packing, a-heiical spring against one follower ring tightly holding the packing in position and thereby biasing said packing against the polish rod, round 0 rings of resilient material disposed in the annular space between said stuffing box and said housing and intermediate said resilient rings, a bushing in said housing below said stumng box, at least a pair of laterally outwardly extending ears at the upper end of said housing. a cap member above said housing in axial alignment therewith having laterally extendnig ears corresponding to those of said housing, bolts passing through the corresponding holes in the lateral ears of said housing and said cap to secure said cap to said housing, said bolts being of smaller diameter than said holes to allow lateral movement of said cap, a grease reservoir in said cap, a grease wiping ring, in the top of said cap, and means for introducing grease into said grease reservoir.

2. A polish rod stuing box comprising, in combination, a housing adapted to be secured to an oil well tubing tee, upper and lower resilient rings inside said housing, a stuillng box of smaller diameter than said housing supported coaxially inside said housing by said resilient rings, packing inside said stulng box comprising, in combination, a spacer ring, at least one ring of upright V-type packing below and at least one ring of inverted V-type packing above said spacer ring, an upper follower ring above said packing, a lower follower ring below said packing, a helical spring against one follower ring tightly holding the packing in position, and thereby biasing said packing against the polish rod, round 0 rings of resilient material disposed in the annular space between said main stuffingy box and -said housing and intermediate said resilient rings, a bushing in said housing below said packing gland, at least a pair of laterally outwardly extending ears at the upper end of said housing, a cap member above said housing in axial alignment therewith having laterally extending ears corresponding to those of said housing, bolts passing through the corresponding holes in the lateral ears of said housing and said cap to secure said cap to said housing, said bolts being of smaller diameter than said holes to allow lateral movement of said cap, a grease reservoir in said cap. a grease wiping ring in the top of said cap, means for introducing grease into said reservoir at a pressure in excess of the well pressure below said packing. which comprises, in combination, a grease cylinder supported in close proximity to said housing, a conduit connection between said cylinder and said grease reservoir. a spring loaded piston in said cylinder for forcing grease from said cylinder into said reservoir, a conduit connection between the tubing T and grease cylinder behind said piston, and means for venting and filling said grease cylinder.

3. A polish rod packing assembly comprising in combination a housing adapted at one end to be secured to a well pipe, said housing having u a bore, the bore adjacent the opposite end from said well pipe being enlarged to form a shoulder and a chamber adjacent said shoulder, a nrst resilient ring in said chamber adjacent said shoulder. a stuillng box concentrically disposed in said chamber and contacting said iirst ring, a plurality oi' additional rings surrounding said box in said chamber and contacting said box and the wall of said chamber, at least one of said additional rings being circular in cross section whereby space is provided in said bore for deformation of said rings. packing in said stumng box disposed to engage in packing contact against said polish rod. a single cover for both said chamber and said stuiilng box. said cover being disposed to cover and compress both said packing and the outermost of said rings, and means loosely securing said cover to said housing and biasing the cover to compress the outermost of said rings and said packing, but allowing tilting and radial movement of said box in said housing.

4. The combination of claim 3in which a wip- .ing ring is mounted on said cover and disposed 8 ring in said chamber adjacent said shoulder. a stuiiingboxconcentricailydisposedinsaidchamberandcontactingsaidiix'string,apluralityofl additional rings surrounding said box in said chamber and contacting said box and the wall of said chamber. at least one or said additional `rings being circular in cross section whereby space is provided in said bore for deformation ot .said rings, packing in said stuinng box disposed outermost oi' said rings. but allowing tilting and radial movement of said box in said housing.

GLEN G. HEBARD.

REFERENCES CITED The following references are of record inthe le ot this patent:

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