US2635331A

US2635331A - Method of forming nonmetallic resilient packing rings

Info

Publication number: US2635331A
Application number: US146377A
Authority: US
Inventors: Dixon T Harbison
Original assignee: Individual
Current assignee: Individual
Priority date: 1950-02-25
Filing date: 1950-02-25
Publication date: 1953-04-21
Anticipated expiration: 1970-04-21

Description

April 21, 1953 D. T. HARBISON 2,635,331

METHOD OF FORMING NONMETALLIC RESILIENT PACKING RINGS Filed Feb. 25', 1.950 :5 Sheets-Sheet 1 L I I gwomv'tom C7 9 Dixon T Harb/son Gum/"441,4

A ril 21, 1953 D. T. HARBISON 2,635,331

METHOD OF FORMING NONMETALLIC RESILIENT PACKING RINGS Filed Feb. 25, 1950 3 Sheets-Sheet 2 Dixon I Harb/son D. T. HARBISON April 21, 1953 METHOD OF FORMING NONMETALLIC RESILIENT PACKING RINGS 3 Sheets-Sheet 3 Fild Feb. 25, 1950 gvwwwkw Dixon [Hark/.900

Patented Apr. 21, 1953 METHOD OF FORMING NONMETALLIC RESILIENT PACKING RINGS Dixon T. Harbison, Fort Worth, Tex. Application February 25, 1950, Serial N 0. 146,377

This invention relates to new and useful improvements in methods of forming non-metallic resilient packing rings.

3 Claims. (Cl. 29-156.62)

,O'ne object of the invention is to provide an im- 1 proved method of forming a packing ring which is particularly adapted for use in reciprocating oil well pumps as well as in other pump cylinders.

Another object of the invention is to provide an improved method of forming a resilient packing ring for a pump plunger, which ring is of such construction and which is split in such manner that a predetermined quantity of well fluids is directed therebehind for urging the same outwardly into sealing engagement with the cylinder wall whereby the pressure of said well fluids is prevented from collapsing said ring inwardly away from said cylinder wall.

An important object of the invention is to provide an improved method of forming a packing ring of resilient material wherein a split annulus is formed and then the exterior thereof is machined while the annulus is contracted to produce a ring having an inherent tendency to expand and a uniform external radius when in its operative sealing position.

A further object of the invention is to provide an improved ring forming method, of the character described, wherein the annulus is cut from a sheet of laminated plastic material whereby the laminations extend at right angles to the axis of said annulus so as to enhance the strength and wearing qualities of the ring.

Still another object of the invention is to pro vide an improved ring forming method, of the character described, wherein the annulus is of slightly greater diameter than the finished ring to permit machining of its periphery and said annulus is split in such a manner as to provide angular oiT-set or overlapping end portions which coact to permit the passage of a predetermined quantity of fluid therebetween.

A construction designed to carry out the invention will be hereinafter described together with other features of the invention.

The invention will be more readily understood from a reading of the following specification and by reference to the accompanying drawings, wherein an example of the invention is shown, and wherein:

Figs. 1,2 and 3 are plan views of an annulus illustrating the steps of cutting the annulus, forming shoulders thereon and commencing the split in accordance with the invention,

Figs. 4 and 5 are transverse, vertical, sectional views, taken on the lines 44 and 5-5 of Figs. land 2, respectively,

Fi 6 is a side elevational view of the partially split annulus shown in Fig. 3,

, Fig. '7 is a plan view of the annulus after the second splitting,

Fig. 8 is a side elevational view of the annulus shown in Fig. 7,

Fig. 9 is a view, similar to Fig. 8, showing the completely split annulus,

Fig. 10 is a transverse, vertical, sectional view, partly in elevation, showing a plurality of split annuli contracted within a tube and separated by spacers with a mandrel extending therethrough,

Fig. 11 is a view, similar to Fig. 10, showing the annuli clamped upon the mandrel in a fixed, spaced relation, preparatory to machining the peripheries of said annuli,

Fig. 12 is a view, partly in elevation and partly in section, of a plurality of completed packing rings mounted upon a pump plunger in sealing engagement with a working barrel, and

Figs. 13, 14 and 15 are fragmentary views in perspective illustrating the ring splitting step,

This application is a continuation-in-part of my co-pending application, Serial No. 734,374,

filed March 13, 1947, now abandoned. Referenceis made to my co-pending application, Serial No. 24,649, filed May 1, 1948, now U. S. Letters Patent No. 2,499,952, issued March 7, 1950.

Heretofore, packing rings of composition material have been made from cylindrical tubes or have been cut from fiat sheets. If the rings originally are of a diameter substantially equal to the working diameter of the finished ring, the same lack the necessary tension when split and placed in use. In the event the original ring is oversize, the same is distorted when compressed to working diameter and does not form a true or perfect circle. Manifestly, a packing ring which fails to snugly engage a cylinder wall throughout its peripheral surface is collapsed and urged away from the wall by the pressure of the fluid being handled. On the other hand, a ring having a uni form radius of curvature and of suflicient tension to snugly engage a cylinder wall is maintained in sealing position throughout its periphery whereby collapsing of the same is prevented. By forming the joint of the ring in such a manner as to admit a predetermined quantity of fluid therebehind, the maintenance of said ringin sealing position is materially assisted.

In carrying out the method of the present invention, an annular body or annulus l0 (Fig. 1) is cut or trepanned from a flat sheet of fibre reinforced plastic material (not shown) which is preferably laminated so. as to increase the strength and wearing qualities of the annulus;

outer peripheral edge portions thereof and these.

flanges are relatively thin (as shownin Figs. 2. and Thus, a. peripheral surface 12' of; reduced width is provided and the annulus is substantially T-shaped in cross-section.

In order to form a joint in. the annulus having: a controlled or predetermined fluid passage" of restricted area, the same is preferably split. in the following manner. As shown in Figs. 3 and 6,, aradial notch or gap [3 is cut through one edge portion of the annulus and its flange H- to a. depth of substantially one-half .its axial thickness. A complementary notch or'gap id.- is. cut through the opposite. flange and edge portion of the annulus at a point offset or spaced from the notch I3 (Figs. '7 and 8). Although the spacing ofthe notches is subject to variation, it has been found that an offset of approximately seventyflve degrees (75) is satisfactory. Smaller or greater spacings may be used when desirable. It is pointed out. that a predetermined amount of material is removed by the forming. of the notches.

A pair of coacting, sealing tongues orbridgjing elements [5 and I6 are provided by splitting. the annulus circumferentially between the. inner end or base portions of the notches i3 and M as shown in Fig; 9. The splitting is accomplished with the removal of substantially'no' material between the tongues i5 and lihwhereby the contacting or contiguous internal surfaces of said tongues coact throughout their coineidentalor overlappinglengths to seal the step .joint against leakage between the notches. Due to the removal of material informing the notches, fluid is permitted to pass radially through and behind or within the annulus when in operation so as to assist in expanding" the same into sealing position.

The split annulus isnext contracted or compressed by being forced into a cylindrical tube or sleeve [1 which. has its bore l8 precision machined throughout. its length to a predetermined uniform or constant diameter (Fig, 1c). The. bore I8 is preferably of slightly greater diameter" than the working diameter of the finished ring to permit subsequent machining of theperipheral surface l2. For economy of manufacture,,a plurality of similar annuli are inserted in the tube I1 and are separated by complementary spacer collars [9. When the annuli are formed with axial flanges ii, the collars iii are T-shaped. in cross-section andhave complementary coaxial flanges 20 at their outer peripheral edge portions for surrounding said annuli flanges. The collars are of less diameter than the annuli and the combined thickness of the flanges H and 20 is less. than. the radial thickness. of said annuli so as. to provide sufficient clearance for the lateral. or radial adjustment of the annuli to the tube bore. i8.

A cylindrical. mandrel. 21,. having a diameter substantially equal to the internal diameters. of the. collars I9 is then teleseoped. or. inserted throughsaid collars and the alternately spaced The. mandrel. 2.]. has a radial shoulder or.

flange 22 formed on one end, while its opposite end is screw-threaded as shown by the numeral 23. With the annuli and collars confined within the tube IT, a suitable nut 24 is threaded upon the mandrel and a spacer ring 25 (Fig. 11) is confined between the nut and the adjacent annulus. By tightening the nut 24, the annuli are clamped upon themandrel in their. contracted or compressed positions. betweenthexmandrel.flange 22 and the spacer ring 25.

As shown in Fig. 11, the mandrel with the annuliclamped thereupon may be removed from thet'ube 1.1 for the final operation. Due to the complementary shape of the collars l9, the annuli: are frictionally held against displacement during subsequent machining of said annuli. Although not illustrated, the peripheral surfaces lZ-of. the annuli are adapted to be ground, machined or otherwise finished to the exact working diameter desired by supporting the mandrel. in a-lathe or other machine tool (no't'shown). The machined annuli have true or perfect circle peripheries so as to accurately'fita' pump cylinder of a predetermined diameter when said an nuli are compressed or contracted; to such diam eter'. Since the annuli are compressed orcontracted, the same are under'tensionso as'to urge their peripheries constantly into sealing engagement with a cylinder wall.

In Fig. 12, the completed packing: rings [0, disclosed in United States Letters Patent 2,499,952, issued March 7,; 1950, are shown mounted upon a tubular plunger 3) within'a well pump cylinder or working barrel 3|. A plurality of spacer collars 32 are carried by the plunger. in superimposed, abutting relation and each collar has a radial flange33 which is T-shaped in.cross=- section. The flanges 33 of adjacent collars 32 coact to form annular grooves 34 complementary to and adapted to receive the. packing rings. [Since the grooves 34 are of greater depth and. slightly greater width than the rings, the'latter may undergo limited lateral and vertical movement. Ihe inherent tendency of the rings to expand maintains the peripherali'surfaces of the same in sealing engagement with the'wall 'ofthe cylinder 31. 7

.Due to the. particular step .joint of each ring and the emotion of its sealing tongues. l5 and it, only a redetermined quantity of well fluids is admitted through the gaps l3 and IA of said joint. These fluids will flow into the annular space between the ring. and its groove 34 so as to act radially outwardlyfupon said ring and thereby assist in maintaining the periphery of the same in sealing. engagement with the. cylinder wall. Thus, collapsing of theringand movement of the same away from thecylinder wall by the pressure of the well fluids is prevented. The spacing of the notches prevents the well fluids from merely flowing into one notch and directly out through the. other notch. Due to the provision of these notches, the Well fluidsmay. flow into one notchwhile flowing out of. the other one and said fluids may pass from one. ring to an adjacent ring. upon reciprocationof the plunger. Although this flow is limited, it is. suflicient. to maintain the rings in sealing engagement. with the cylinder walland to wash away sand, grit-or other extraneous matter. Of course, thereisno. flow past. all of. the .rings on. any onesstroke. of: the plunger, although there. isa more. or less constant. movement of the. well. fluids.

The. step of splittingtheannulisifl between thenotches or gaps i3 is importantandnovel; The

fibre-reinforced plastic or synthetic resin material from which the packing rings are formed has been substantially completely hardened or polymerized and will not receive a permanent distortion. For this reason, it is not possible to cut a circumferential slot between the bottoms of the notches l3 and then deform or distort the annulus so as to bring the resulting tongues l5 and [6 into permanent sliding engagement.

, The strength and resiliency of the plastic material prevent such a step which is common in the metal-working arts. Stated in another manner, the elastic limit of the plastic material is so near its ultimate strength that permanent distortion without destruction cannot be obtained with practical success.

This problem has been overcome by the novel step of splitting the annulus without the removal of any material, although a very small amount of material may be removed in dressing or smoothing the abutting faces of the tongues l5 and IS. The smoothing operation is desirable but not essential. The preferred mode of splitting includes positioning the annulus 10 upon a suitable mandrel or anvil 35, as shown in Fig. 13. The anvil is circular in cross-section and receives the annulus snugly so as to support the same in an adequate fashion. A curved chisel or wedge 36 is employed for the splitting and includes a body 31 having its lower end tapered or bevelled upon an arc to form a curved chisel edge 38. It is to be noted that the curvature of the edge 38 is substantially equal to the curvature of the annulus periphery, and that the arcuate length of the edge is substantially equal to the circumferential distance between the bottoms of the notches [3.

The wedge 36 is moved into engagement with the surface of the ring or annulus In, as shown in Fig. 14, and is then, preferably, given a sharp and sudden impetus which results in splitting of the ring as shown in Fig. 15. The edge 38 is not moved into engagement with the mandrel 35, and the resultant action is one of splitting rather than cutting or slitting. Since no material has been removed, the tongues l5 and I6 spring into permanent abutment as soon as the wedge is withdrawn. There may be present a slight roughness of the adjacent faces of the tongues,

and for this reason, moderate smoothing or reinforced synthetic resin, including, forming an annulus of synthetic resin having reinforcing laminations extending transversely to the axis of the annulus, removing material to form a substantially radial first gap in one edge portion of 6. the annulus, removing material from the opposite edge portion of the annulus at a point circumferentially spaced from the first gap to form a substantially radial second gap, and driving a wedge into the annulus between the gaps and transverse to the axis of the annulus to split the latter between the gaps substantially parallel to the plane of the laminations.

2. The method of forming non-metallic resilient packing rings which includes, cutting an annulus from a laminated sheet of substantially hard synthetic resinous material whereby the annulus has laminations extending transversely to its axis, cutting notches approximately half way through the thickness of the annulus at circumferentially spaced points in the upper and lower portions thereof, moving into engagement with the outer periphery of the annulus between the bottoms of the notches a wedge having an arouate edge formed with the same radius of curvature as is the periphery of the annulus so as to conform substantially to the periphery of the annulus, and imparting force to the wedge to split the annulus in a transverse plane between the notches to provide constantly contacting overlapping tongues between the notches.

3. The method of forming non-metallic resilient packing rings which includes, cutting an annulus from a laminated sheet of substantially hard synthetic resinous material whereby the annulus has laminations extending transversely to its axis, cutting notches approximately half way through the thickness of the annulus at circumferentially spaced points in the upper and lower portions thereof, moving into engagement with the outer periphery of the annulus between the bottoms of the notches a wedge having an arouate edge formed with the same radius of ourvature as is the periphery of the annulus so as to conform substantially to the periphery of the annulus and of a length substantially equal to the distance between the notches, and imparting force to the wedge to split the annulus in a transverse plane between the notches to provide constantly contacting overlapping tongues between the notches.

DIXON T. HARBISON.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,186,890 Gill June 13, 1916 1,314,142 Loudenbeck Aug. 26, 1919 1,314,143 Loudenbeck Aug. 26, 1919 1,323,192 Kottusch Nov. 25, 1919 1,380,136 Doan May 31, 1921 1,386,997 Elliott Aug. '7, 1921 1,450,200 Bruninga Apr. 31, 1923 1,625,508 Thorne Apr. 19, 1927 2,003,934 Hansel June 4, 1935 2,046,988 Winter July '7, 1936 2,218,638 Christenson Oct. 22;, 1940 2,255,504 Current Sept. 9, 1941 2,344,687 Fischer Mar. 21, 1944