US2845286A

US2845286A - Packing for polish rods

Info

Publication number: US2845286A
Application number: US574917A
Authority: US
Inventors: Case Harold; Warren C Ames
Original assignee: Marlo Co Inc
Current assignee: Marlo Co Inc
Priority date: 1956-03-29
Filing date: 1956-03-29
Publication date: 1958-07-29
Anticipated expiration: 1975-07-29

Description

July 29, 1958 H. CASE 'ET AL 2,345,286

PACKING FOR POLISH RODS Filed March 2a, 1956 2 Sheets-Sheet 1 G H INVEN TOR;

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M Arrav/wsrs I Julyf29, 1958 'H. cAsE ET AL 2,845,286

PACKING FOR POLISH RODS I Filed March 29, 1956 2 Sheets-Sheet 2 INVENTORS #40040 C455 y haw/95w C'- Ana;

Unite PACKING FOR POLISH RODS Application March 29, 1956, Serial No. 574,917

4 Claims. (Cl. 286-16) Our invention relates to improvements in a stufiingbox for a polish rod, and to improved sealing devices for use in said stuffing-box. As is well-known, a polish-rod is a vertical cylindrical rod, which is vertically reciprocated, in order to actuate a pump which pumps oil out of an oil well. i A pumping system which includes a polish-rod and a stuffing-box for said polish rod, is well known. Such systems are illustrated, for example, in Ratigan U. S. Patent No. 2,3 80,189, dated July 10, 1945; and in Ratigan U. S. Patent No. 2,685,465, dated August 3, 1954.

The well-known polish rod smiling-box may be of the type which requires a source of lubricant oil other than the oil of the oil-well, as illustrated in said Ratigan U. S. Patent No. 2,685,465; or said stufiing-box may be of the self-oiling type, in which the lubricating oil which is suptates atent O pliedto the polish-rod, is the oil which is pumped out I of the well. 7 t

One type of material which is used to make the packing blocks of the stulfing-box, is disclosed in said Ratigan U. S. Patent No. 2,685,465. This material is resilient, somewhat compressible, hard and oil-resistant. It is exemplified by an oil-resistant synthetic rubber, such as neoprene.

While oil is being pumped from the well, said oil lubricates the polish-rod, so that it is unnecessary to supply lubricant from a source other than the oil of the oil well, to the polish-rod or to the sealing surfaces of the blocks of the stufiing-b'ox, which contact with the polish-rod;

However, the oil may cease to flow from the oil-we'll,

dining a normal pump-oh period which maybe eight hours to ten hours, while the polish-rod and the sealing blocks are continuously reciproc-ated'. In such case, the

. polish-rod and the sealing block or blocks are'not supplied with lubricating oil from the oil-well.

There is a high coefficient of friction between the nonlubricated polish-rod and the above mentioned hard material of said blocks. Unless the stuffing-box is provided with alubricating system which is independent of the oil from the well, as disclosed in said Ratigan U. S. Patent No. 2,685,465 dated August 3, 1954, the sealing surface or surfaces of the packing block or blocks wear rapidly during this pump-off period. Also, even if the polishrod is lubricated by lubricant which is supplied independently of the oil of the oil well, said sealing surface or surfaces of said hard material of said block or blocks wear. In such case, the lubricant drains out of the stuffing box, even if lubricant is supplied from a sourceind-ependent of the oil well. According to our invention, we provide a polish-rod stuffing-box which has a plurality of identical one-piece blocks. which can be made of said type of material disclosed in. said. Ratigan U. 5. Patent No. 2,685,465. Each block has the usual vertical stand-pipe hole, and-the usual polish-rod hole. These blocks are superposed in the stufiingabox assembly, so thatthe stand-pipeextends inthe usual. manner, vertically through said superposed stand- 2 pipe holes, and the polish-rod extends in the usual manner through the polish rod holes.

In the vertical assembly which is made according to our invention, each said block has top and bottom, lateral or horizontal planar faces. One of these lateral faces of said blocks is unrecessed. Each of the proximate lateral face of each block has a vertical recess, which has avertical, cyclindrical recess-wall, and an inner, planar horizontal recess-wall. This inner recess-wall has the vertical cylindrical, polish-rod hole, through which the polish rod extends. It is optional to provide a close, sliding fit between said polish-rod recess-hole and the polishqod. Preferably, there is a slight clearance between the polish rod and said polish-rod recess ho le. I

Each block has a through-and-through, upstanding and laterally disposed bevel split which extends horizontally or laterally from said recess-hole through which the polish-rod extends, to and through the outer, vertical peripheral wall of said block. This bevel splitis preferably nonradia-l to the vertical axis of said-polish-rod recesshole. The inclined walls of said bevel split may be planar. In the original unstressed shape of the block, these split-walls may optionally be slightly spaced from each other or contact with each other.

When the block is subjected to the usual vertical pressure in the st'ufling-box', said walls of said bevel split are kept pressed tightly against each other, to provide sealing contact. These bevel walls of the split may be planar. Since each block is resilient, the walls of the bevel sp'lit may be easily moved away from each other by hand manipulation, so that a special lubricating and sealing ring may 'be' easily inserted into the recess. After" this has been done, the released resilient block frictionally holds this special insert ring in the recess.

This ring insert is made of material which is easily c'ompress'ible, so that said ring is molded and compressed against the polish-rod at 20 C r-30 C. from itsor igfinal' original uncompressed shape, the insert ring fits closely and is held frictional-1y in the recess, and the hole ofthe insert ring is alined with the recess-hole, and the" insert ring may extend axially or vertically beyond the planar part of the recessed face of the block.

The blocks maybe assembled in pairs in the stufiing box. In the initial stufling-box assembly, before. the vertical pressure is applied by the usual pressurehe'ad to said assembly,- the planar parts of the recessed faces of each pair abut each other or are very close to each other, and thetwo uncompressed insert rings of each pair may abut each other at their adjacent horizontal or lateral faces,

so that the two abutting insert ring'sa're' held'ag'ain'st' vertical movement relative to their blocks in the assembly, before and after said vertical pressure is applied.

The usual vertical pressure is applied to the blocksand to their insert rings in the assembly, while the polish-rod extends through all the vertical holes of all the insert rings and through all the alined recess holes of all the blocks. The polish-rod may have a close fit in the vertical holes of the insert rings, when said insert rings have their initial uncompressed shape in the assembly. As a result" of the usual vertical pressure, each insert ring is molded and permanently compressed both vertically and horizontally while the polish-rod extends through all the holes or said insert nings, so that the vertical wall of the hole of each compressed insert ring is provided with a close sealing fit against the polish-rod. Also, the planar parts of the proximate, recessed faces of the blocks are kept tightly pressed against each other in sealing contact by said applied vertical pressure. As above noted, this vertical pressure is always maintained in the stuffing-box. As a result of this vertical molding pressure, each ring is thus finally molded and comprrssed both vertically and horizontally, while the polish-rod extends through the hole of each insert ring, thus providing a close sealing fit between the inserted polish-rod and the abutting internal Wall of the hole of each insert ring. Also, the finally molded and compressed ring tightly fills the respective recess of the respective block with a close, sealing fit. Also, the height of the finally molded and compressed ring is equal to the height of the respective vertical, cylindrical recess-wall of the compressed block. As above noted, the original height of the original uncompressed insert ring may optionally be slightly greater than the height of the vertical recess-wall of the respective block. All the blocks may be identical, and all the insert rings may be identical.

These special insert rings, after being thus molded and permanently compressed, serve to guide the polish-rod and to lubricate the polish-rod to maintain an oil-tight seal at the polish-rod, and also provide oil-tight seals in the adjacent recesses of said assembled blocks.

These special ring inserts may be made of the material which is disclosed in U. S. Patent No. 1,709,086, dated April 16, 1929, and in U. S. Patent No. 2,221,453. Said material of said ring inserts and said rings themselves, are well known commercially as Red Water. These ring inserts are preferably split rings in their original uncompressed form, in which they are put into the recesses of the blocks.

These ring inserts have selected absorbent vegetable fibers. Prior to being inserted into the recesses of the blocks, these absorbent fibers are impregnated with lubricant for the polish-rod. These vegetable fibers are twisted with alloy metal strands which have a low coefficient of friction, in order to form a very flexible combination material of lowfriction. These special insert rings also have a thin, braided covering or envelope which is made of said absorbent fiber. The fibers of said covering or envelopes are also impregnated with lubricant, before the rings are inserted into the recesses of the blocks.

Under the usual vertical pressure which is applied and maintained in the stufling-box assembly, these special insert rings are easily compressed and hence yield in every direction and they are maintained in their permanently densified and compressed and molded form in the stuffing-box. The low-friction metallic component of said material of said rings metallizes the vegetable fiber of said rings, thus producing a contact surface or sealing surface of very low friction at the cylindrical periphery of the polish-rod.

Said Red Water packing material, although flexible and easily bendable and easily compressible to a final dense form, has suflicient rigidity so that when a length thereof is bent to ring shape, said length remains in said ring shape, unless it is forced out of said ring shape.

Each insert ring is thus provided a sufiicient initial supply of absorbed lubricant, so that said insert ring will not harden or burn out, even if the polish-rod is reciprocated for eight to ten hours during a normal pump-off period, even if no lubricant is supplied during said pumpoff period to said ring. During said normal pumpoif period, the rings efiectively lubricate the polish-rod. The polish-rod preferably does not contact with the hard material of said blades.

When oil is pumped from the well, said pumped oil forms a film around the polish-rod, and said pumped oil is absorbed by the special compressed and molded insert rings in the stuffing-box, thus renewing the supply of lubricant of said rings, so that the specialrings remain effective and sealing, during a subsequent normal pump-off period of eight to ten hours.

Since the general construction of a polish-rod pumping system is well-known, and such construction is disclosed, for example, in said Ratigan U. S. patents, it is unnecessary to describe well-known parts in detail.

Since the Red Water material of said special sealing rings is well-known, it is unnecessary to illustrate said material in detail in the drawings. It is sufficient to designate said Red Water material as consisting of absorbent vegetable fibers which are twisted with low-friction alloy metal strands, said ring having absorbent vegetable fibers which are exposed at the inner vertical face of said original insert ring, and also when the insert ring is finally compressed and molded to final permanent shape.

The improved blocks, in addition to being used in the improved assembly later disclosed herein, may be used as replacement units in existing polish-rod stuffing-boxes, as in the stuffing-boxes described in said Ratigan patents. The vertical peripheral edge-walls of said improved blocks may have an oval shape, or a circular shape, or any non-circular shape, depending upon the shape of the cavity of the housing of the respective stufling-box.

A preferred embodiment of the invention is disclosed in the annexed drawings and in the following description.

Fig. l is a vertical sectional view of one type of the improved assembly, partially in elevation.

Fig. 2 is a section on the line 2-2 of Fig. 1.

Fig. 3 is a section on the line 33 of Fig. 2.

Fig. 4 is an exploded perspective view of a pair of the improved blocks in the superposed position of the block in the assembly of Fig. 1, and of the respective insert rings.

Fig. 5 is a perspective view of the improved block and its insert, prior to the vertical compression of the insert, and showing a part of the polish-rod.

Fig 6 is a perspective view of two of the blocks and their inserts, in assembly position, also showing the polish-rod.

The resilient block B, which may be made of the hard and slightly compressible and resilient material described in said Ratigan U. S. Patent No. 2,685,465, has opposed parallel and

planar faces

2 and 3, which are perpendicular to the vertical axes of the stand-pipe hole 5 and of the polish-rod hole 9 of said block B. For convenience, these

faces

2 and 3 are designated as the lateral or horizontal faces. In this embodiment, the block B has a vertical peripheral wall 4, which has an oval shape or eggshape. As above noted, said wall 4 may be cylindrical.

The stand-pipe hole 5 is adjacent the apex or narrow end of block B.

The face 2 is the recessed face of each block B. This face 2 has a recess 6 adjacent the wide end of said block B. Said recess 6 has a vertical cylindrical wall 7, and an inner horizontal, planar wall 8. This inner wall 8 is provided with the vertical and cylindrical polish-rod hole 9.

The special sealing-ring and lubricating ring R, which is made of said Red Water material, is preferably a split ring in original shape, prior to being compressed and molded by the vertical pressure which is applied in this assembly. This original ring R has abutting ends 10 and 11, which are in final sealing contact in the respective recess 6 of the respective block B after the vertical assembly pressure has been applied. Said abutting ends 10 and 11 may have original planar walls which are vertical, or said original planar walls may be inclined relative to the vertical direction. -The vertical molding pressure forces said ends 10 and 11 into final tight, sealing contact. The inner cylindrical vertical face of said molded and compressed lubricating and sealingring R makes sealing contact with the polish-rod P. Said vertical pressure is applied in the assembly, as above noted, to compress the original rings R to final dense and compressed permanent shape, while the polish-rod P extends through the bore 9 of each sealing and lubricating ring R, in order to mold and acompress the inner vertical Wall of each ring R into final accurate cylindrical, sealing shape, which makes tight sealing contact with the polish-rod P. When thus subjected to vertical pressure in the assembly, each insert ring R also makes tight sealing contact with-the

walls

7 and 8 of the respective recess 6 of the respective block B. The polishrod P may fit closely with-asealing fitin the polish-rod hole 9 of each block B, or there is preferably a slight clearancebetween thepolish-rod P and the vertical edge of the polish-rod-holeof each block B. The polish-rod P is guided in itsreci-procating, vertical movement by'the vertical wall of the hole of each compressed sealing and lubricating ring R.

Said original ring R, prior to being subjected to vertical molding pressure in the assembly, initially closely fills the respective recess 6. When initially put into recess 6, the outer horizontal face of said ring R may be flush with the unrecessed horizontal and planar part of the recessed face 2. As an alternative, said horizontal face of ring R may extend vertically beyond the horizontal and planar part of the recessed face 2, as shown in Fig. 5. As above noted, the blocks B are somewhat vertically compressible, so that they are in the compressed state in the final assembly. Hence, even if ring R is initially flush with face 2, said ring R and its block B will be compressed in the final assembly, and the ring R will be molded and compressed by the vertical pressure. When the ring R and its block B are subjected to vertical pressure in the stuffing-box, the outer horizontal face of ring R is finally compressed to be flush with the planar part of the recessed face 2 of the compressed block B, and the compressed ring R thus makes accurate tight sealing contact with the periphery of polish-rod P and with the

walls

7 and 8 of the recess 6.

In this embodiment, the beveled split of the one-piece block B extends from the polish-rod hole 9 to and through the peripheral edge-wall 4, so that the

faces

2, 3 and the inner horizontal recess-wall 8 of recess 6 and the vertical recess-wall 7 of recess 6 have respective slits S. This split also provides a slit W in the peripheral edge-wall 4.

When this block B is used in a stuffing-box, the edgewall 4 of the block B has a tight sealing fit in the vertical wall of the cavity of the housing H of the stuffingbox. Also the interfitting edge-walls of said split have a sealing fit in the final assembly in the housing H. Each block B is subjected to and maintained under the usual vertical pressure in the stufiing box. This vertical pressure keeps the edge-walls of the bevel split pressed against 'each other in tight sealing contact. This vertical pressure is applied and maintained by the usual head 18 and the usual pressure-applying bolts 18a.

As above noted, the one-piece block B is resilient. Hence, said one-piece block B can be sprung apart at its bevel split S-W, in order to insert the uncompressed, original ring R. Also, the edge-walls of the bevel split SW of block B may be normally slightly separated in the normal, unstressed shape of block B, thus facilitating the insertion of the split and resilient block B and its assembled original and originally uncompressed ring R into the cavity of the housing H, or into a holder 19 located in the housing H.

Fig. 1 shows a lantern-ring holder 19, which has top and

bottom flanges

20 and 21. The invention is not limited to the use of said lantern-ring holder 19, which is well known per se.

The housing H has a bottom wall 15 and a vertical wall 14. The usual bottom plate is provided at the inner face of wall 15.

Fig. 1 also shows the usual stand-pipe 22 which has a bore 23. The upper end of stand-pipe 22 extends into the usual stationary tube 24, which is integral with the clamping head 18. The usual removable plug 25 is provided. The usual sealinggland G is provided. This ,gland has the usual screws-26. -Since the assembly of and their rings R are assembled prior to applying the vertical ,pr essure,'the'rings R of said pair of blocks abut each other or are directly adjacent eachother if they do not abut, and the respective slits S 'W are angularly offset, as by an angle of 30 degrees.

As shown in Fig. 4, the slit S-Wof each block B is non-radial and is offset relative to the vertical axis 'of the respective polish-rod hole 9.

In the final assembly of Fig. 1, after the vertical pressure has been applied by clamping head 18, the compressed blocks B are thus assembled in respective pairs, thus providing a stuffing-box which has a tight-sealing fit at the inner vertical wall of housing H and at the polish-rod P.

One of the important features of our invention is to provide a slit or split S-W which is non-radial relative to the axis of the polish-rod hole 9, and which is offset relative to said axis. As shown in Fig. 6, this provides the respective pair of assembled blocks with slits or splits S--W which are not vertically alined in the assembly of a pair of blocks. This uniformly distributes the applied vertical pressure, to provide sealing contact between the walls of each slit or split S-W.

In the assembly, the bevel splits 10--11 of the respective rings are also angularly offset, as by an angle of 30.

We claim:

1. In final combination with a vertical polish-rod, a stufiing-box through which said polish rod extends vertically and axially, a packing in said stuffing box, said packing including upper and lower superposed annular blocks which have proximate horizontal faces and remote horizontal faces; said blocks being made of material which is resilient, somewhat compressible and hard; said blocks fitting against the interior vertical face of said stufling box; the lower block having a vertical inner annular recess which extends below its respective proximate face, the upper block having a vertical inner annular recess which extends above its respective proximate face, said recesses having horizontal end-walls at their opposed lower and upper ends, said end-walls having vertical polish-rod bores through which said polish rod extends; respective ring inserts located in said respective vertical recesses, each ring insert abutting a respective end-wall; said ring inserts having respective upstanding slots, and being made of material which is permanently deformable and compressible under applied vertical pressure of said blocks when said blocks are forced vertically towards each other in said stufling box; said blocks have through-and-through upstanding slits from the walls of said recesses to the vertical edge walls of said blocks; said blocks being sufiiciently spreadable at their said slits for easy seating of said ring inserts in said recesses; the outer annular faces of said ring inserts fitting closely in said recesses; the inner annular faces of said ring inserts fitting closely against said polish-rod in an initial assembly of said polish rod and blocks and ring inserts; said stufiing box having a rigid support for the bottom face of said bottom block; pressure means for downwardly forcing said upper block towards said lower block and for exerting vertical pressure on said ri g inserts to change said initial assembly to a final combination, said blocks being sufficiently hard and said ring inserts being sufficiently permanently yieldable under said vertical pressure to permanently decrease the original height of said ringinserts and to permanently decrease their original internal diameters by cold-molding the interior annular faces of said ring inserts against said polish rod; said final combination having the proximate horizontal faces of said blocks abutting each other under said vertical pressure, the proximate ends of said ring inserts abutting each other under said vertical pressure, the total height of said ring inserts being permanently less than their original total height, the internal diameters of said ring inserts being permanently less than their original internal diameters, and the'inner annular faces of said ring inserts being in tight, sealing contact with said polish-rod.

2. A combination according to claim 1, in which the slits of said blocks are wholly angularly offset.

3. A combination according to claim 2, in which the slits of said blocks have horizontal legs which are nonradial relative to said polish-rod bases.

4. A combination according to claim 1, in which each ring-insert originally extends inwardly beyond the respective proximate inner face of the respective block.

References Cited in the file of this patent UNITED STATES PATENTS 696,747 Rigby Apr. 1, 1902 1,339,599 Garren May 11, 1920 1,709,086 Miller Apr. 16, 1929 1,982,252 Heggem Nov. 27, 1934 2,221,453 Miller Nov. 12, 1940 2,351,343 Kelley June 13, 1944 2,380,189 Ratigan July 10, 1945 2,685,465 Ratigan Aug. 3, 1954