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Publication numberUS3228703 A
Publication typeGrant
Publication date11 Jan 1966
Filing date5 Nov 1962
Priority date5 Nov 1962
Publication numberUS 3228703 A, US 3228703A, US-A-3228703, US3228703 A, US3228703A
InventorsWilson James A
Original AssigneeWilson James A
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Line stripper and packing element therefor
US 3228703 A
Abstract  available in
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Claims  available in
Description  (OCR text may contain errors)

Jan. 11, 1966 J. A. WILSON 3,228,703

LINE STRIPPER AND PACKING ELEMENT THEREFOR Filed Nov. 5, 1962 2 Sheets-Sheet 1 $11 Y S 10 ll HO'Q: I04 l/f Fig. l s 80 80 Q g H372 1H2 m E IO! 99 -7 INVEN TOR.

@ James A.Wilson United States Patent 3,228,703 LINE STRIFFER AND PACKING ELEMENT THEREFOR James A. Wilson, 4425 San Gabriel Drive, Dallas, Tex. Filed Nov. 5, 1962, Ser. No. 235,231 17 Claims. (Cl. 277-73) This invention relates to well tools and more particularly to wire line strippers.

An object of the invention is to provide a new and improved device for stripping well fluids from a flexible member or wire line as it is withdrawn from a well bore.

Another object is to provide a wire line stripper having means for moving an elongate packing element into sealing engagement with a flexible member or wire line which is movable therethrough wherein the force holding the packing element in sealing engagement with the wire line is exerted along a substantial length of the packing element whereby the area of sealing engagement between the packing element and the wire line is relatively great.

Still another object is to provide a wire line stripper which utilizes an optimum amount of the substance of the packing element which is worn away or consumed as the wire line moves therethrough and thus prolongs the useful life of the packing element and decreases the number of times operations must be interrupted to replace worn out packing elements.

A further object is to provide a wire line stripper having a tubular body in which the elongate tubular packing element is receivable and means movable longitudinally in the body for progressively moving longitudinally aligned portions of the packing element radially inwardly toward the wire line.

A still further object is to provide a wire line stripper wherein longitudinally aligned portions of the packing element of progressively smaller external diameters are moved progressively radially inwardly toward the wire line by means movable longitudinally in the body as the packing element wears or is consumed due to the rncvement of the wire line through the longitudinal bore or pasage of the packing element.

Another object is to provide a wire line stripper wherein a plurality of telescoped fluid pressure operated pistons progressively move longitudinally aligned portions of the packing element radially inwardly as the substance of which the packing element is formed wears and is consumed as the wire line moves frictionally therethrough and wherein each piston is telescopical in the next outer piston.

Still another object is to provide a wire line stripper wherein the pistons initially move downwardly as a unit moving certain longitudinal portions of the packing element radially inwardly until the limit of longitudinal movement of the outermost piston in the body is stopped whereupon the movement of each of the other pistons continues until the limit of movement of each next outermost piston in the body is successively reached.

A further object is to provide a wire line stripper wherein the telescopical pistons move successively in the body, the outermost piston first moving an end longitudinal portion of the tubular packing element of greatest external diameter radially inwardly as the packing element is consumed by the frictional engagement of the wire line moving therethrough until outermost piston reaches its limit of movement in the body and then the other pistons move successively downwardly to force other intermediate portions of the tubular packing element of progressively smaller external diameters inwardly.

A further object is to provide a wire line stripper having a substantially tubular packing element formed of a deformable or plastic substance, such as rubber, which sealingly engages the wire line movable through the longitudinal passage or bore of the packing element wherein the packer element is provided with longitudinally spaced external shoulders of progressively smaller diameter engageable by an operator means of the wire stripper which successively moves longitudinally aligned portions of the packing element of progressively smaller diameters radially inwardly toward the wire line.

A still further object of the invention is to provide a packing element for a wire line stripper having a longitudinal passage through which a line may extend and having longitudinal sections or portions of progressively greater diameters providing external longitudinally spaced shoulders of progressively greater diameters wherein the portions are movable radially inwardly in accordance with their diameters.

Additional objects and advantages of the invention will be readily apparent from the reading of the following description of a device constructed in accordance with the invention, and reference to the accompanying drawings thereof, wherein:

FIGURE 1 is a longitudinal sectional view of a wire line stripper embodying the invention showing the telescopical pistons in fully extended positions relative to each other and the body of the stripper;

FIGURE 2 is a view similar to FIGURE 1 showing the pistons in their fully telescoped positions relative to one another and the body of the wire line stripper;

FIGURE 3 is a sectional view taken on line 3-'-3 of FIGURE 1;

FIGURE 4 is a view taken on line 4-4 of FIGURE 1;

FIGURE 5 is a longitudinal sectional view of a modified form of the wire line stripper;

FIGURE 6 is a longitudinal sectional view of still another modified form of the wire line stripper;

FIGURE 7 is a fragmentary sectional view of a modified form of the spring member of the wire line stripper illustrated in FIGURE 6; and,

FIGURE 8 is a fragmentary sectional view of still another modified form of the spring member illustrated in FIGURE 6.

Referring now particularly to FIGURES 1 through 4 of the drawing, the wire line stripper 10 includes an elongate tubular body or housing 11 comprising an upper cylindrical or tubular section 12 threaded on a lower cylindrical or tubular section 14 over which the upper section is telescopable and securable thereto by means of internal threads 15 on the lower end of the upper body section and external threads 16 on the intermediate portion of the lower body section. The lower body section has a reduced dependent portion 13 which is externally threaded whereby it may be connected in the upper end of a well pipe or member 20.

The lower body section has an inner upwardly opening annular recess 21 which provides an upwardly facing annular shoulder 22. The annular external flange 24 of a bottom tubular guide 25 is receivable in the annular recess 21 and the guide is held against downward movement in the bore or passage 26 of the dependent portion 18 of the lower body section into which it extends by the engagement of the lower surface of the flange with the upwardly facing annular shoulder 22. The annular guide 25 may be formed of two semicircular sections 25a and 25b to facilitate the insertion in its central bore or passage 27 of the flexible member or wire line 28. The upper surface 29 of the lower guide 25 is coplanar with the lower internal upwardly facing annular surface 30 of the lower body section whereby the upwardly facing shoulders 29 3 and 30 support the lower annular surface 33 of a substantially tubular packing element 34. The packing element is formed of a suitable deformable or plastic substance, such as rubber, which may be forced into sealing engagement with the external surfaces of the wire line movable through the longitudinal central bore or passage 35 of the packing element. The packing element may have a longitudinal cut or slit as at 36, FIGURE 4, to facilitate the insertion of the wire line intothe longitudinal central passage of the packing element.

The longitudinally aligned bottom portion 37, the intermediate portion 38 and the top portion 39 of the packing element are of progressively smaller external diameters and provide the upwardly facing annular shoulders 41, 42 and 43, respectively. The outermost edge of the bottom downwardly and outwardly beveled shoulder is disposed below the annular top end surface 44 of the lower body section and is engaged by the bottomdownwardly and outwardly extending lower end surface or shoulder 46 of an outer tubular or annular piston 47 which is also located below the top end surface of the lower body section when the outermost piston is in the upper position in the body 11 illustrated in FIGURE 1. The external surface 50 of the outermost piston is slidably engageable with the internal surface 51 of the lower body section so that the packing element may not extrude or flow upwardly between these two surfaces as the outermost piston is moved downwardly in the body and compresses and moves radially inwardly the bottom portion 37 of the packer element. The outer piston has an external annular top flange 52 provided with an external annular recess is which is disposed an O-ring 54 or other suitable sealing means which seals between the piston and the internal surface 55 of the upper body section 13. The outer piston has an internal annular flange 56 whose downwardly facing shoulder 57 engages the upwardly facing shoulder 58 f the external annular lower end flange 59 of the tubular or annular intermediate piston 60 so downward movement of the outer piston in the body will also cause downward movement of the intermediate piston. The outer piston has an internal annular recess immediately above the shoulder 57 in which is disposed an O-ring 63 or other suitable sealing means which seals between the intermediate piston and the outer piston.

The intermediate piston has a downwardly and outwardly beveled lower end surface or shoulder 66 which engages the upwardly facing intermediate shoulder 42 of the packing element. The outer annular surface 69 of the external lower end flange 59 of the intermediate piston is slidably engageable with the internal surface 70 of the outer piston whereby downward movement of the intermediate piston relative to the outer piston, after downward movement of the outer piston in the body has been arrested by the engagement of its lower end with the upwardly facing shoulder or surface 30 of the lower body section, will cause the portion of the packing element therebelow to be moved radially inwardly. Upward movement of the outer piston is limited by the engagement of its upper end with the internal downwardly facing annular shoulder 71 of the internal annular flange 72 of the upper body section while upward movement of the intermediate piston in the body is limited by the engagement of the shoulders 58 and 57 ofthe intermediate and outer pistons.

The top shoulder or surface 43 of the packing element is engaged by the planar lower end surface 75 of the top guide 76 which may be formed of two semicircular sections 76a and 76b. The top guide is receivable in the lower end of the bore or passage 79 of the inner tubular 'or annular piston 80 and has an external annular flange 84 whose outer surface 85 is slidably engageable with the internal cylindrical surface 86 of the intermediate piston 60 whereby none of the plastic substance of which the packing element is formed may extrude therebetween when the inner piston 80 is moved downwardly relative to the intermediate piston after downward movement of the intermediate piston in the body has been arrested by the engagement of its lower end with the surface 30 of the lower body section.

The lower annular end surface or shoulder 87 of the inner piston engages the upper annular shoulder or surface 89 of the external flange 84 of the top guide. The external annular flange 9% at the lower end of the inner piston is provided with an external annularrecess in which is disposed an O-ring or other suitable sealing means 91 which seals between the inner piston and the intermediate piston. Downward movement of the intermediate piston relative to the inner piston is limited by the engagement of the downwardly facing shoulder 93 of the internal annular flange 94 at the upper end of the intermediate piston with the upwardly facing shoulder 96 of the inner piston provided by the external flange 90. The inner piston extends slidably through the central passage or bore 97 of the top flange 72 of the upper body section and an O-ring or other suitable sealing means 98 disposed in an internal annular recess thereof seals between the top flange and the external surface of the inner piston 80 above the external flange on the lower end thereof.

The upper end portion of the intermediate piston extends into a downwardly facing internal lannular recess 99 of the top flange 72 of the upper body section.

Fluid under pressure is introduced into the body or housing 11 above the upwardly facing end surfaces of the outer and intermediate pistons and above the upper shoulder 96 of the external flange of the inner piston through an inlet fitting 101 threaded in a lateral bore 102 of the upper body section, located immediately below the downwardly facing shoulder or surface 71 thereof, and through the conduit 104 connected tothe fitting from any suitable source of fluid under pressure.

The area of the upwardly facing surface of the outer piston exposed to the pressure of the fluid introduced into the body and defined by the line of sealing engagement of the O-ring 54 with the internal surface 55 of the upper body section and the line of sealing engagement of the O-ring 63 with the external surface 10-3 of the intermediate piston is substantially greater than the area of its downwardly facing end surface or shoulder 46 which engages the lower shoulder 41 of the packing element. The upwardly facing area of the intermediate piston exposed to the pressure of the fluid introduced into the body through the fitting 101 and defined by the line of sealing engagement of the O-ring 63' with the external surface of the intermediate piston and the line of sealing engagement of the O-ring 91 with the internal surface of the intermediate piston is somewhat smaller than the area of the lower end surface or shoulder 66 of the intermediate piston which engages the intermediate upwardly facing shoulder 42 of the packing element. It will now be apparent that fluid pressure introduced into the body will tend to move the outer piston downwardly before it will cause any movement of the intermediate piston relative to the outermost piston since the downward force or pressure per unit area exerted by the outer piston on the shoulder 41 is obviously much greater than the downward force or pressure per unit area exerted by the intermediate piston on the shoulder 42 for any given value of the fluid pressure.

The area of the upwardly facing surface provided by the external lower end flange of the innermost piston exposed to the fluid pressure introduced into the body and defined by the line of sealing engagement of the:

0-ring 91 with the internal surface of the intermediate piston and the line of sealing engagement of the O-ring 98 with the external surface of the inner piston is substantially smaller than the area of the planar surface .5 stopped by the engagement of its lower end with the upwardly facing shoulder 30 of the lower body section 14 since the force or pressure per unit area exerted by the intermediate piston on the intermediate shoulder 42 of the packing element is much greater than the downward force or pressure per unit area exerted by the inner piston through the top guide on the upper surface of the packing element.

The pistons are biased toward their positions in the body illustrated in FIGURE 1 by a spiral spring 110 whose lowermost coil of greatest diameter is received in an upwardly facing annular recess 111 of the upper body section and rests on the annular upwardly facing shoulder 112 thereof. Outward movement of the lowerrnost coil is limited by its engagement with the internal vertical annular shoulder 113. The uppermost coil of smallest diameter of the spiral spring abuts the lower surface of a retainer ring 115 mounted on the upper end of the inner piston whose upward movement on the innermost piston is limited by a split lock ring 116 whose inner portions are received in an external annular recess 117 of the innermost piston and whose outer portions extend outwardly of the inner piston and engage top surface of the retainer ring. The outer surface of the top flange 72 extends upwardly and inwardly to provide clearance for the spring.

Due to the spiral configuration of the biasing spring 110, each coil of the spring may nest o-r telescope in the next lowermost coil whereby the vertical height of the spring when it is in its fully collapsed or retracted position, illustrated in FIGURE 2, is shorter than would be the case if the spring were merely helical. As a result, the provision of the spinal spring, the diameter of whose coils decreases upwardly, permits the total length of the line stripper to be shorter for a given distance of effective travel of the inner piston. The provision of the internal recess 99 in the top flange of the upper body section also increases the distance of effective travel of the intermediate and inner pistons. These features of the wire stripper result in a compact device of relative short length, low weight and easy handling and operation.

In use, the lower body section 14 is connected to the upper end of a well pipe or member 20, the lower end of the wire line 28 is moved downwardly through the tubular pistons in the upper body section, the upper body section and the lower body section while the upper body section is disconnected and spaced from the lower body section. The bottom guide is then disposed about the wire line and moved downwardly in the lower body section until its external flange 24 enters into the recess 21 and arrests further downward movement of the bottom guide. The packing element 34 is placed about the wire line 28 by inserting the wire line through the longitudinal slit or cut 36 into the longitudinal passage 35 thereof. The packing element is then moved downwardly into the lower body section until its planar bottom surface engages the surfaces and 29 of the lower body section and the bottom guide. The two sections 76a and 76b of the top guide are next placed on the upper surface or shoulder 43 of the packing element and about the wire line. The top body section is then telescoped over the upper end portion of the lower body section and secured thereto by means of the threads 15 and 16 thereof. During such downward telescoping movement of the upper body section and its connection to the lower body section, the pistons which are now held in their uppermost positions in the upper body section by the spring 110 move with the upper body section to the positions illustrated in FIGURE 1. The spring 110 now yieldably holds the inner piston 85) in its uppermost position. Due to the engagement of the external and internal flanges of the three pistons, the intermediate and outer pistons are also yieldably held in their upper positions by the spring. The engagement of the upper end of the outer piston 47 with the shoulder 71 of the body limits such upward movement of the three pistons in the body. As long as no fluid under pressure is introduced into the wire stripper body through the conduit 104 and the fitting 101, the packing element is not subjected to any forces tending to cause it to sealingly engage the wire line.

It will be apparent that the installation of the bottom and top guides 25 and 76 and the packing element requires considerable attention and is time consuming when these guides and the packing element are separate from one another. To facilitate installation of these elements in the body of the wire stripper, the sections of the bottom and top guides are bonded or otherwise secured to the bottom and top surfaces or shoulders 33 and 43, respectively, of the packing element and the longitudinal cut or slit 36 extends diametrically from the external surface of the packing element to the inner edge of the external shoulder 41 so that the two semicircular sections of each of the guides, whose edges are aligned with the slit, will be pivoted apart about an axis spaced from their external surfaces as the portions of the packing element on opposite sides of the cut 36 are moved apart to permit the passage of the wire line through the cut into the longitudinal passage 35 of the packing element. At this time therefore the two sections of each guide are spaced apart from one another and the wire line is insertable therebetween so that when such portions of the packing element are moved back to positions adjacent each other, the wire line will extend not only through the longitudinal passage 35 of the packing element but also through the longitudinally aligned passages 27 and 118 of the two guides. The guides and the packing element may thus be positioned as a single unit about the wire line and between the spaced upper and lower body sections prior to the connection of the body sections to one another.

Alternatively, the packing element may be formed by two sections so that the longitudinal cut or slit extends completely diametrically through the packing element. Each half of the packing element would then have bonded to its opposite end surfaces one section of each guide. The guides and the packing element would then be easily assembled about the wire line stripper by moving the two halves of the packing element, and the guide sections secured thereto, toward one another prior to the telescoping and connection of the two body sections to one another.

The guide members are formed of a relatively rigid wear resistant substance, such as brass, cast iron or the like, and their passages are of greater diameter than the diameter of the wire line to permit passage therethrough of the usual flexible length markers or flags which may be secured to the wire line.

When it is desired to raise the wire line 28 upwardly to withdraw it from the well tubing 20 and to strip well fluids from the wire line as it is withdrawn, fluid under pressure is introduced into the tubular body and such fluid pressure acting on the upwardly facing surfaces of the three pistons now biases them downwardlv a ainst the force exerted by the spring. The force with which the pistons are biased or forced downwardly by the fluid pressure may be controlled by any suitable control means connected to the conduit 104 such as a pump which supplies the fluid under pressure to the stripper or a pressure regulator means for regulating the pressure in the conduit 104. During downward movement of the outer piston, air in the body below the flange 52 of the outer piston may escape from the body through the apertures 119 of the upper body.

The three pistons tend to move downwardly in the body and exert a downward force on the upwardly facing shoulders 41, 42 and 43 of the packing element and compress the packing element against the planar surfaces 30 and 29 of the lower body section and the bottom guide. In addition, downward movement of the outer and intermediate tubular pistons tends to force or move the portions of the packing element below the downwardly facing end surfaces or shoulders 46 and 66 of these pistons radially inwardly toward the wire line. The pressure of the fluid introduced into the body is so regulated that such forces exerted on the packing element by the three pistons now hold the packing element in sealing engagement with the wire line which extends through the longitudinal bore 35 of the packing element, the plastic substance of which the packing element is formed flowing or extruding into any crevices or recesses of the wire line to effect such sealing. During longitudinal movement of the wire line through the packing element, the frictional engagement of the wire line with the relatively soft plastic substance of the packing element causes the packer element to wear or be consumed by abrasion by the wire line itself and by any abrasive materials moved through the packing element with the wire line.

The application of downwardly directed forces on the three longitudinally spaced surfaces or shoulders 41, 42 and 43 of the packer now causes the packing element to engage the wire line with substantially equal or uniform force throughout the length of the area of sealing contact of the packing element with the wire line. The annular shoulders 41 and 42 of the packing element are spaced longitudinally of the packing element so that the lower shoulder 41 is located more than one-third but less than one-half of the length of the packer from the bottom thereof, and the intermediate shoulder 42 is located more than three-fifths but less than seveneighths of the length of the packer from the bottom thereof. For example, the bottom shoulder may be located two and a half inches from the bottom of the packing element, the intermediate shoulder one and three-fourths inches from the bottom shoulder and the top surface or shoulder 43 one and one-half inches from the intermediate shoulder. It will therefore be seen that the outer. piston travels a greater distance in the body before its downward movement is arrested by its engagement with the shoulder 30 and the distance traveled by the intermediate piston until it engages the shoulder 30 after such downward movement of the outer piston is arrested, Similarly the inner piston travels a smaller distance relative to the intermediate piston as compared to the distance of travel of the intermediate piston relative to the outer piston. The external shoulders or surfaces 41, 42 and 43 are of progressively greater widths since the longitudinally aligned portions 37, 38 and 39 are of progressively smaller diameter. For example, the external diameters of these longitudinally aligned portions may be four and seven-eighths inches, three and three-eighths inches and two and one-half inches with the diameter of the longitudinal passage 35 being fiveeighths of an inch. Due to this particular relationship of the dimensions of the packing element and the relative lengths of distances of travel of the pistons, the length of sealing engagement of the packing element is relatively 'great throughout the useful life of the packing element since such length decreases very slowly as the packing element wears and since the outer portions of the packing element below the shoulders 41 and 42 are moved or flow radially inwardly as the pistons move downwardly and the packing element is slowly worn away or consumed. This relatively great length of sealing engagement of the packing element with the wire line of course reduces the force per unit area with which the packing element must engage the wire line to provide the desired sealing and stripping effect. The wear or abrasion of the packing element varies with the friction between the wire line and the packer which increases relatively very greatly with any relatively small increase in the force per unit area with which the internal surface of the packing element engages the wire line. Since the wear or abrasion of the packing element is thus proportional to the force of the packing element per unit length of wire line moved therethrough is maintained at a low, although constantly increasing, value as its length continuously decreases until the downward movement of the intermediate piston is arrested since the outer and intermediate pistons move outer portions of the packing element radially inwardly. The length of sealing engagement of the packing element with the wire line decreases more rapidly when the downward movement of the intermediate piston is stopped since the force per unit area with which the packing element must engage the wire line must now be increased to provide the desired sealing and stripping results since the width of the packing element is now relatively small and the worn away substance of the packer must be replaced by the longitudinal compression of the packing element. When the length of such sealing engagement is decreased to a critical point at which the packing element can no longer properly engage the wire line and prevent leakage therebetween at the available or desired highest value of the pressure fluid introduced into the body, the remaining portions of the packing element must be removed and a new packing element inserted in the body. Such remaining portions of the packing element are discarded and constitute waste. It is of course desirable to minimize such waste both because of the cost of the substance of which the packing element is formed and also because of the cost in labor and of time lost during each stoppage of operations necessitated by the need to replace a worn packing element with a new packing element. It has been found that approximately fifty to sixty percent of the substance of packing elements having configurations similar to that of the packing element disclosed in the patent to Wilson, 3,013,825, issued December 19, 1961, and used in wire strippers having a single plunger or piston of the type described in this patent, still remain in the wire stripper at the time the sealing effectiveness of such packing elements is reduced to such an extent that a new packing element is needed. In contradistinction, it has been found that only thirty to forty percent of the substance of a packing element having the configuration of the illustrated and described packing element of theinvention and used in the illustrated and described wire stripper remain and must be discarded when such packing element has been worn to such extent that it can nolonger function effectively.

During use, the three pistons initially move downwardly as a unit until the outer piston is moved to its lower position in the body wherein its lower end engages the upwardly facing shoulder 30 of the lower body section. During such downward movement, the portions .of the packing element directly below its lower shoulder 46 are moved radially inwardly, As the wear or consumption of the packing element continues with the movement of the wire line therethrough, the intermediate and inner pistons continue to move downwardly, the intermediate piston now causing the portion of the packer element below its downwardly facing end surface or shoulder 66 to be moved radially inwardly as the wear or-consumption of the packing element continues. The intermediate piston continues to move downwardly as the wear of the packing element continues until its further downward movement 'is arrested by its engagement with the upwardly facing shoulder or surface 30 of the body. The inner piston now moves downwardly relative to the intermediate piston and acting through the top guide 76 compresses the now cylindrical packing element of relatively small thickness downwardly as such wear continues until the packer element is worn away to such an extent that it no longer functions eifectively.

The top and bottom guides are of a relatively hard and wear resistant material and hold the wire line in longitudinal central alignment with the body and the pistons during its movement through the stripper.

The wire line may of course be lowered into and Withdrawn from the well pipe or member 20 many times before the packing element is Worn to such an extent that it must be replaced. When it is desired to lower or move the wire line downwardly into the well member, the fluid pressure is exhausted from the valve body through the fitting H31 and the conduit 104 by means of the control means connected to the conduit 104 whereupon the spring lit moves the inner piston upwardly. As the inner piston moves upwardly its external flange engages the upper internal flange of the intermediate piston and moves the intermediate piston upwardly therewith. Subsequently, as the intermediate piston moves upwardly, its external flange engages the internal flange of the outer piston to cause the outer piston also to move upwardly until the three pistons move back to the upper positions illustrated in FIGURE 1 wherein further upward movement thereof is arrested by the engagement of the upper surface of the outer piston with the inner shoulder 71 of the inner flange 72 of the top body section. The pistons no longer bias the packing element toward engagement with the wire line and the packing element now does not impede downward movement of the wire line through the stripper. The wire line, of course, supports well tools of one type or another and moves downwardly due to its own weight and to the weight of such tools.

It will be apparent that the wire line stripper may also be used to prevent upward flow of well fluids from the well pipe during downward movement of the wire line into the well member if the weight of the portion of the wire line below the stripper and of the well tools attached thereto is sufficiently great to overcome the frictional force between the packing element and the wire line while it is held in sealing engagement with the wire line.

It will be noted that the lower end surfaces 46 and 66 of the inner and intermediate pistons are preferably beveled downwardly and outwardly and that the shoulders 41 and 42 of the packing elements engaged thereby are also preferably beveled in order to facilitate the radial inward movement or displacement of the portions of the packing element below the shoulders during downward movement of such pistons in the stripper body. It will be apparent however that the shoulders of the pistons, of the packing element or of both the pistons and the packing element may be flat and extend perpendicularly relative to the longitudinal axis of the pistons and of the packing element.

It will now be seen that a new and improved wire line stripper has been illustrated and described which includes a tubular body or housing having a deformable or plastic tubular packing element therein for sealingly engaging a wire line which is movable through the body and the packing element and that the body is provided with operator means for forcing the packing element into sealing engagement with the wire line which progressively and sequentially moves longitudinally aligned outer portions of the packing element radially inwardly toward the wire line as the substance of the packing element is consumed as the packing element wears or is abraded at the areas of contact thereof with the wire line.

It will further be seen that the longitudinally aligned portions of the packing element are of progressively greater external diameters and provide longitudinally spaced annular external shoulders engageable by such operator means.

It will further be seen that the operator means for forcing radially inwardly such outer portions of the packing element include a plurality of tubular or annular pistons mounted in the body for longitudinal movement and engageable with such shoulders of the packing element to exert longitudinal forces thereon.

It will further be seen that the pistons are telescopable into one another and have surfaces exposable to fluid under pressure which biases the pistons for movement in the body into engagement with such shoulders of the packing element and that the surfaces of such pistons simultaneously exposed to such fluid pressure and the areas thereof engaging such shoulders of the packing elements are of such relative areas that an outer piston will be moved in the body in an operative direction tending to displace the outer portion of the packing element below the shoulder engaged thereby radially inwardly toward the wire line before the fluid pressure is effective to move the next inner piston relative to such outer piston in such direction.

It will further be seen that the pistons are provided with coengageable means, such as the internal and external flanges thereof, which cause each piston to move the next inner piston therewith when such piston is moved downwardly in the operative direction in the stripper body until the movement of such piston is arrested by engagement of a shoulder thereof with a stop surface or shoulder of the body whereupon the next inner piston is movable by such fluid pressure in the valve body and relative to such piston whose movement has been arrested.

It will further be seen that the stripper is provided with a biasing means, such as the spring 110, which biases the pistons in the body in a direction opposite to the direction of the force exerted by the pistons tending to move the packing element into sealing engagement with the wire line whereby the packing element is freed of such force tending to move it into engagement with the wire line each time the fluid pressure is removed from the pistons.

It will further be apparent that the fluid pressure may be varied by any suitable control means as required to maintain proper sealing engagement of the packing element with the wire line. The pressure is of course maintained at as low a value as is practicable to effect such sealing engagement in order to minimize the wear or abrasion of the packing element. Since the combined area of the pistons exposed to such pressure and still movable in the operative direction progressively decreases relative to the combined area of the shoulders of the packing element engaged by the still movable pistons, as the movement of first the outer piston and then the intermediate piston in the operative direction is arrested, the value of the fluid pressure introduced into the body may have to be increased at such times to maintain the packing element in proper sealing contact or engagement therewith.

It will now be seen that a new and improved packing element for use in a wire line stripper embodying the invention has been illustrated and described which includes a substantially tubular body having a central longitudinal passage through which a wire line may move and also having longitudinally aligned portions of progressively greater diameters providing longitudinally spaced annular external shoulders which are engageable by the operator means of the wire stripper which force 'the packing element into sealing engagement with the wire line.

It will further be seen that the bottom annular shoulder of the packing element is longitudinally spaced from the opposed hat or planar surface of the packing element a distance more than one-third and less than one-half the total length of the packing element and that the intermediate annular shoulder is longitudinally spaced from the flat bottom surface of the packing element a distance more than three-fifths but less than seven-eighths of the total length of the packing element.

It will further be seen that each of the shoulders engageable by such pistons faces in a direction opposite to that of the stationary or bottom end surface and that each such shoulder is of greater width and of smaller diameter than the next shoulder which is spaced between such shoulder and the bottom surface.

It will further be seen that the packing element having the configuration and the proportions illustrated and described provides for optimum or maximum utilization of the substance of which the packer is formed whereby the 1 1 waste of the substance is kept at a minimum and the use ful life of the packer is increased resulting in a reduction in the cost of operation and a decrease in the frequency of replacement of the packer elements per unit of length of wire line moved through the packing element.

Referring now particularly to FIGURE 5, the wire line stripper 150 is substantially similar to the wire line stripper and employs the same packing element 34 and the same bottom and top guides and 76 as the wire line stripper 10 illustrated in FIGURES 1 through 4. The wire line stripper includes a substantially tubular body 151 comprising an upper tubular or cylindrical section 152 secured to a lower cylindrical or tubular section 153, over which the lower end of the upper section is telescoped by means of internal threads 154 on the lower end of the upper section and external threads 155 on an intermediate portion of the lower section. The lower body section has a reduced dependent portion 158 which is externally threaded at its lower end whereby it may be connected in the upper end of a well member or pipe in the same manner that the reduced dependent portion 18 of the body of the stripper 10 connected in the upper end of a well pipe or member 20. The lower body section has an inner upwardly opening annular recess 159 which provides an annular upwardly facing shoulder 160. The annular external flange 24 of the bottom guide 25 is receivable in the annular recess 159 and the bottom guide is held against downward movement in the bore or passage 162 of the dependent portion 158 of the lower body section into which it extends by the engagement of the lower surface of the flange with the upwardly facing annular shoulder 160. The upper surface 29 of the bottom guide is coplanar with the annular planar surface 164 of the lower body section whereby the upwardly facing shoulders 29 and 164 support the lower annular planar bottom surface of the tubular packing element 34.

The bottom annular shoulder 41 of the packing element is engaged by the downwardly and outwardly beveled shoulder or end surface 165 of an outer tubular or annular piston 167 whose lower end portion is telescoped into the lower body section. The external annular surface 168 of the outer piston is slidingly engaged with the internal annular surface 169 of the lower body section so that the plastic substance of which the packing element is formed may not extrude or flow therebetween as the outer piston is moved downwardly in the body.

'The outer piston 167 is provided with an external annular shoulder 174 which is engagea'ble by the top annular surface 175' of the outer piston to limit upward movement of the outer piston in the stripper body. The outer piston is biased upwardly in the body by a spring 177 whose lower end engages the upwardly facing annular shoulder 178 of the lower body section and whose upper end engages the bottom surface 179 of the external flange of the outer piston. An O-ring 180 or other suitable sealing means is disposed in an internal annular recess of the outer piston and seals between the outer piston and the outer cylindrical surface 181 of the intermediate piston 183. The lower end portion of the intermediate piston is telescoped within the outer piston and its external cylindrical surface 181 is slidingly engageable with the internal cylindrical or annular surface 185 of the outer piston whereby the plastic substance of which the packing element is formed may not flow upwardly therebetween when the intermediate piston is moved downwardly relative to the outer piston. The lower downwardly and outwardly beveled end surface or shoulder 185 of the intermediate piston engages the intermediate shoulder 42 of the packing element and the piston moves or displaces the portion of the packing element immediately below the intermediate shoulder radially inwardly as the intermediate piston moves downwardly in the stripper body.

The intermediate piston 183 extends upwardly into the upper reduced top portion 188 of the top body section and about the lower end portion of the inner piston 189. The intermediate piston has an O-ring 190 or other suitable sealing means disposed in an internal annular recess thereof which seals between the external annular cylindrical surface 191 of the inner piston and the intermediate piston. The internal cylindrical surface 193 of the intermediate piston slidingly engages the external surface 191 of the inner piston.

The intermediate piston is biased upwardly by a spring 194 disposed about the intermediate piston whose lower end bears against the upwardly facing end shoulder or surface 175 of the outer piston and whose upper end bears against the annular downwardly facing shoulder 195 of the external annular flange 197 at the upper end of the intermediate piston. Upward movement of the intermediate piston is limited by the engagement of its upper annular end shoulder or surface 199 with the annular downwardly facing shoulder 200 provided by an external annular flange 202 of the inner piston. The upward movement of the inner piston in the body is in turn limited by the engagement of its upwardly facing external annular shoulder 204 with the lower surface of the internal top flange 206 of the upper body section.

The upper portion 212 of reduced external diameter of the inner piston above the shoulder 204 thereof extends upwardly through the bore or passage 209 of the top flange 206 and an O-ring 211 disposed in an internal annular recess of the top flange seals between the top flange and the outer cylindrical surface 212 of the inner piston which is of smaller diameter than the outer surface 191 thereof.

It will be apparent that the inner piston is biased upwardly in the body by the same spring 194 which biases the intermediate piston 183 upwardly due to the engagement of the shoulders 199 and 200 of the inner and intermediate pistons, respectively. The lower end portion of the inner piston telescopes over the top guide 76 and its lower annular end surface or shoulder 215 engages the upper surface of the external annular flange 84 of the top guide.

The outer piston 167 is movable downwardly against the force exerted by the spring 177 by fluid pressure introduced into the tubular body through the lateral port 173 which acts on the upwardly facing surf-aces'of the outer piston whose area is defined by the line of sealing engagement of the O-ring 171 with the internal surface 172 of the upper body section and the line of sealing engagement of the O-ring 180 with the external surface 181 of the intermediate piston. The intermediate piston is movable downwardly by the force of such fluid pressure acting on the upwardly facing surfaces of the intermediate piston whose area is defined by the line of sealing engagement of the O-ring 180 with the external surface 181 of the intermediate piston and the line of sealing engagement 7 of the O-ring 190 with the external surface 191 of the inner piston. The inner piston is movable downwardly by the force of such fluid pressure acting on an upwardly facing surface of the inner piston whose area is defined by the line of sealing engagement of the O-ring 190 with the external surface 191 of the inner piston and the line of sealing engagement of the O-ring 211 with the external annular surface 212 of the inner piston.

It will be apparent that when fluid under pressure is introduced into the body through the port 173, these upwardly facing surfaces of the three pistons are simultaneously exposed to such fluid pressure and are all simultaneously biased downwardly. Since the upwardly facing area of the outer piston exposed to such fluid pressure is considerably greater than the area of its downwardly facing end surface or shoulder 165 which is engaged with the lower bottom shoulder 41 of the packing element, if any movement of the pistons is possible, only the outer piston will move downwardly in the body until its lower end engages the upwardly facing shoulder or surface 164 of the lower body section. The intermediate piston will only then be moved downwardly in the tubular body since the area of its upwardly facing surface exposed to such fluid pressure is substantially equal to the area of its downwardly facing end surface or shoulder 186 which engages the intermediate annular shoulder 42 of the packing element. The inner piston will remain in its upper position since the area of its upwardly facing surface exposed to such fluid pressure is much smaller than the area of the lower surface 75 of the top guide engaged with the top surface 43 of the packing element.

It will now be apparent that when the body is secured to a top end of a well pipe or member by means of the reduce-d threaded dependent end portion 158 of the lower body section and the wire line, such as the wire line 28, extends through the top and bottom guides and the longitudinal passage 35 of the packing element, the three pistons may be biased downwardly to force the packing element to move into sealing engagement with the wire line by introducing fluid under pressure into the body through the lateral port 173. As the wire line is moved upwardly through the stripper and the packing element is held in sealing engagement with the wire line, the frictional engagement between the wire line and the surfaces of the packing element defining the longitudinal passage 35 causes the packing element to wear or abrade. As such wearing away or consumption of the plastic substance of which the tubular packing element is formed occurs, the volume of the packing element decreases and the force of the pressure acting on the outer tubular piston moves the tubular outer piston downwardly. During such downward movement of the outer tubular piston the portions of the packing element below the end surface or shoulder 165 thereof are moved or displaced radially inwardly. When the packing element 34 has worn away to such an extent that the outer piston reaches the limit of its downward movement due to the engagement of its lower end with the shoulder 164 of the lower body section, the force of the fluid pressure acting on the upwardly facing surface of the intermediate piston is now effective to move the intermediate piston downwardly. As the wearing away or consumption of the packing ele- .ment continues, such downward movement of the intermediate piston 183 causes the portion of the packing element below its shoulder 186 to flow or be displaced radially inwardly. When the intermediate piston reaches the limit of its downward movement, due to the engagement of its shoulder with the upwardly facing shoulder 164 of the lower body section, the force of such fluid pressure acting on the upwardly facing surface of the inner piston becomes eflective to move the inner piston, and the top guide 76 engaged thereby, downwardly as the wear or consumption of the packing element continues.

It will be noted that the length of sealing engagement of the packing element 34 with the wire line does not decrease at any time until downward movement of both the outer piston and the intermediate piston is arrested. As a result, the area of the sealing engagement or contact of the packing element remains constant until the packer element is worn away by the amount or volume of the substance of the packing element initially located below the shoulders 165 and 186 of these pistons and that the length of this sealing contact, and therefore the area of contact or seal-ing engagement, begins to decrease only when the downward movement of the intermediate piston 14 is arrested and the inner piston moves downwardly displacing the upper portions of the now tubular packing element downwardly as the wear continues.

It will now be seen that the independently downwardly movable pistons of the wire line stripper 150, like the pistons of the wire line stripper 10, maintain the element in sealing engagement with the wire line stripper with substantially uniform force throughout the full area of contact of the packing element with the wire line since in both cases the upwardly facing areas of the three pistons are simultaneously subjected to the force of the fluid pressure introduced into the body.

it will also be seen that first the outer piston 167 and then the intermediate piston 183 is moved downwardly to displace or move outer portions of the packing element radially inwardly as the wear or consumption of the packing element progresses during movement of the wire line therethrough so that the effective area of sealing engagement of the packing element with the wire line remains at a maximum during this period of time and the rate of wear or consumption of the substance of the packing element per unit length of wire line moved therethrough is held to a minimum since the area of sealing engagement does not decrease during this time and the force per unit area with which the packing element must be held in engagement with the wire line stripper is relatively small due to the large area of such sealing engagement. When the inner piston moves downwardly as the wear or consumption of the substance of the packing element continues, the area of such sealing contact or engagement decreases and the force per unit area with which the packing element is held in contact with the wire line must be increased and the rate of wear or consumption per unit length of wire line moved through the packing element increases due to the now increased friction between the packing element and the wire line.

It will now also be seen that the chief difference in mode of operation of the two wire line strippers is that the three pistons of the wire line stripper 10 initially move downwardly simultaneously until the downward movement of the outer piston is completed, the intermediate and inner pistons then continuing to move downwardly together until the downward movement of the intermediate piston is arrested and then the inner piston alone moving downwardly while the three pistons of the line stripper each move independently of the others during their downward movement, the outer piston first moving downwardly until its downward movement is arrested, then the intermediate piston moving downwardly until its downward movement is arrested, and finally the inner piston moving downwardly. I

It will now be seen that the sequential movement of the pistons of the two wire line strippers due to the same fluid pressure is predetermined by different ratios of the areas of the different pistons exposed to such fluid pressure and the areas thereof engaging the external shoulders of the packing element so that the force per unit area which each piston exerts on the shoulder of the packing element it engages is smaller than the force per unit area exerted by the next outer piston on the shoulder of the packing element it engages.

It will further be seen that due to this independent and sequential movement of the three pistons of the wire stripper 150, the area of sealing contact or engagement of the packing element with the wire line remains large and constant until a considerable amount of substance of the packing element has been consumed and only then does the area of sealing engagement slowly decrease as the length thereof decreases as the consumption of the packing element continues.

Referring now particularly to FIGURE 6 of the drawing, the wire stripper 250 embodying the invention includes a tubular housing or body 251 whose upper cylindrical or tubular section 252 telescopes over and is releasably secured to the lower section 253 by means of the internal threads 254 v lower coil of the spring member.

1 5 of the lower end of the upper section and the external threads 255 of the lower section.

.The lower section has a reduced dependent portion 257 which is externally threaded at its lower end whereby the body may be connected in a well pipe or member. The bottom guide 25 is positioned in the bore or flow passage 259 of the lower body section and its external flange 24 is received in the upwardly opening annular recess 260 of the lower body section, the engagement of the bottom surface of the external flange 24 with the upwardly facing shoulder 262 defining the lower end of the annular recess 260 limiting downward movement of the bottom guide in the passage 259. The top surfaces 29 and 264 of the bottom guide and of the bottom section of the body are coplanar and support the planar bottom surface 266 of a substantially tubular packing element 267 formed of a suitable deformable or plastic substance, such as rubber.

The outer surface of the packing element is provided throughout its length with an external upwardly facing spiral shoulder 270. The diameters of the coils or turns of the shoulder decrease upwardly so that the lower end portion of the packing element is of largest external diameter and the upper end is of smallest external diameter.

The spiral vertical outer surface 272 of the packing element extends between each pair of longitudinally aligned and spaced turns or coils 270a, 2763b 27071 of the spiral upwardly facing shoulder 270 so that coils 272a, 272b 27211 of the spiral vertical surface be- ,tween the surface 266 of the bottom section and the extend only partially the width of the element or completely therethrough so that the packing element is formed of two sections and the sections of the top and bottom guides 76 and 25 may be bonded or otherwise secured to the opposite end surfaces of the packing element.

The packing element is receivable in a spiral operator or spring member 275 formed of a resilient substance,

such as metal, which may have a substantially rectangular cross-sectional configuration so that the inner surfaces 276a, 2761) 27611 of the coils 275a, 275b 275m of the spring member correspond in configuration -and engage the corresponding vertical spiral outer surfaces 272a, 272k 27221 and so that the bottom shoulder 278a of the lowermost coil of the spring member engages the surface 254 of the lower body section and the bottom shoulders 278b, 2780 278n of other coils of the spring member engage the upwardly facing coils 270a, 27Gb 27011- of the spiral shoulder of the packing element 267.

The width or height of the resilient member of which the operator member is formed is substantially greater than the height of the surfaces 272, Le, the distance between the adjacent turns or coils of the shoulders 274D, whereby each coil of the spring member has a lower portion which telescopes into the upper portion of the next The spring member is of substantially tubular formv and encloses all outer "surfaces of the packing element except the planar bottom surface 266 and the top planar surface 232 thereof.

The top planar surface 282 of the packing'element is engaged by the downwardly facing bottom surface 75 of the top guide 76. The top annular surface 89 of the external annular flange 84 of the top guide is energized by the bottom end surface or shoulder 283 of the-lower tubular portion 284 of a piston 285 which telescopesint-o then-ppermost coil 27511 of the operator member 275.

The piston has an external annular flange 288 provided with an external annular recess in which is disposed an O-ring 289 which seals between the piston flange and the internal cylindrical or annular surface 291 of the top body section below the lateral port 293. The upper portion 295 of the piston of. reduced external diameter extends upwardly through the bore or passage 2% of the top internal flange 297 of the upper body section. The internal flange 297 is provided with an internal annular recess in which is disposed an O-ring 298 which engages the external cylindrical surface 299 of the upper portion 225 to seal between the piston and the internal flange. Upward movement of the piston in the body is limited by the engagement of the annular upwardly facing shoulder 300 of the piston with the lower surface of the top flange 297. The lower surface 303 of the flange engages the top surface 304 of the top coil 27511 of the spiral spring. The lateral ports 305 of the upper body section permit escape and entry of' air from and into the body below the piston as the piston move-s do'wnwardly and upwardly in the body.

The inherent characteristics of a spiral spring of uniform material and having a uniform cross-section 'cause each coil thereof to be moved longitudinally telescopically relative to the next coil of smaller diameter of the spring by a smaller force than that required to move a coil of smaller diameter telescopably relative to its adjacent next small-er coil. Since each coil of the spiral spring member thus provides a greater resistance against movement thereof parallel to the longitudinal central axis of the spring member into telescoped position in the next coil of greater diameter than the resistance offered to such telescoping movement of each coil of the spiral spring of greater diameter, it will be apparent that when a downward force is exerted on the top coil 275n of the spiral spring member and the lower shoulder 278a of the lowermost coil 275a of greatest diameter is held against downward movement due to its engagement with the surface 262, the coil 2755 of the next largest diameter will telescope further inwardly into the coil 275a, and thus move or displace a greater length of the outer portion 273a of greatest external diameter of the packing element radially inwardly, than any such telescoping movement of any of the other coils of the spring member into their adjacent coils. When the downward movement of the coil 275]) is arrested by the engagement of its shoulder 2751) with the shoulder 264 of the lower body section, the next coil 2750 continues to move telescopically into the coil 275b continuing to displace the longitudinally aligned portion 271% of the packing element radially inwardly at a greater rate than any such telescoping movement of any of the other coils of smaller diameters into their adjacent coils. The coils will thus be moved downwardly relative to their immediately l-ower adjacent coils of the spring until such movement of the coils is successively arrested by the engagement of the lower shoulders thereof with the shoulder 264 until downward movement of the piston is finally arrested by the engagement of the bottom surface 75 of the top guide with the upper-surface 29 of the bottom guide 25.

In use, the wire line is run downwardly through the passage of the piston 295 and through the spiral spring or operator member 275 and the upper body section while the two sections of the body are separated. The bottom guide is then disposed about the wire line and positioned in the flow passage 259 of the lower body section. The tubular packing element is then disposed about the wire line by means of the longitudinal slit or cut 274 thereof, the resilient rubber parting of course to permit such insertion of the wire line into the longitudinal central passage 274a of the packing element. The operator or spring member 275 is then lowered downwardly over the packing element to the position illustrated in FIGURE 6. The top guide 76 is inserted into the top coil 27511 of the operator member and on the top surface or shoulder 282 of the packing element. The lower portion 284 of the piston 285 is telescoped over the top guide and into the top coil 27511 of the spring member. The upper body section 252 of the body is then threaded on the lower body section. If the guides are secured to the bottom and top surfaces 266 and 282 of the packing element, the installation of these elements is of course facilitated whether the slit extends only partially or completely diametrically through the packing element in the manner described in connection with the packing element 34.

All longitudinal vertical surfaces of the packing element are now enclosed by the spiral spring member and the sliding engagement of the inner and outer surfaces of the telescoped coils of the spring member prevent flow of the substance of the packing element therebetween since the engagement of the outer vertical surface of the bottom coil 27511 with the internal surface 291 of the body below the ports 305 limits outward movement of the lowermost coil 275a of the spring member and therefore of all the other coils of the spring member and the engagement of the internal surface 27611 of the top coil 27511 with the external surface of the lower portion 284 of the piston prevents radial inward movement of the top coil and therefore of all the other coils.

It will thus be apparent that when the piston exerts a downward force on the top coil 27511 of the spring, the packing element will be compressed and moved into sealing engagement with the wire line which extends through its central longitudinal passage 274a. When it is desired to Withdraw the wire line from the well member and through the well stripper, fluid pressure is introduced into the body above the external flange 288 of the piston by means of any suitable conduit connected to the body at the port 293 and provided with suitable means for controlling and regulating the fluid pressure transmitted into the body. As the wire line moves upwardly, the plastic substance of which the packing element is made, such as rubber, wears at the area of contact of the packing element with the wire line. The downward force exerted by the fluid pressure on the upper shoulder 304 of the top coil 275n of the operator or spring member is now transmitted to all the coils of the spring member but since, due to the inherent characteristics of the spiral spring member, a lesser force is required to move the second lowermost coil 275b longitudinally downwardly and parallel to the central axis of the spring, than the force required to so move the upper coils of smaller diameter, the coil 2751) will move downwardly at a greater rate than any of the other coils of the spring member and move or displace the outer portion 273a of the packing element below its shoulder 278b radially inwardly at a greater rate than the rates of displacement of the other portions 273b 273n to replace the Worn or consumed portion or volume of the substance of the packing element. As the movement of the wire line and the wearing or consumption of the packing element continues, the downward movement of the coil 2751) continues until its downward movement is arrested due to the engagement of its lower shoulder 278b with the surface 264. At this time the coil of next smaller diameter, coil 278c, moves downwardly at a greater rate and displaces the portion of the packing element 273]; below its shoulder 278cradially inwardly at a greater rate than the rates of displacement of such other portions 273a 27311 until its downward movement is similarly stopped. The other higher coils similarly continue to move downwardly at such different rates and their downward movements are successively arrested until all of the substance of the packing element is consumed and the bottom surface 75 of the top guide engages the upper surface 2% of the bottom guide. In actual practice, of course, all of the packing element is not consumed since the packing element becomes ineffective at the available or desirable value of the fluid pressure introduced into the stripper body to provide the proper sealing contact or engagement with the wire line when the length of the area of such contact has been reduced to a critical degree. The remaining portion of the packing element is discarded and a new packing element 267 is inserted in the wire stripper body.

The resilient force of the spring or operator member 275 biases the piston longitudinally upwardly in the body and whenever the fluid pressure is relieved or exhausted from the body, the force of the spring member is effective to move the piston to the upper position illustrated in FIGURE 6 so that the packing element is no longer held in sealing engagement with the wire line and the longitudinal movement of the wire line is not then impeded by such engagement with the packing element.

It will be apparent that the wire line stripper 250 provides the same desired result of a relatively great length and large area of sealing engagement of the packing element with the wire line throughout the useful life of the packing element because the length of the packing element decreases relatively slowly as the packing element is closed since the outer portions 273a, 2731; 27311 are progressively and successively displaced radially inwardly as the wear of the packing element progresses to replace such worn or consumed amount or volume of the packing element.

It will also be apparent that the force with which the packing element sealingly engages the packing element is substantially uniform throughout the length of the packing element since the lower shoulders 27812 2781i engage the shoulders 270a 27011 at longitudinally spaced locations and the force tending to move and hold the packing element in sealing engagement with the wire line is thus applied about and to the packing element at a plurality of longitudinally spaced locations of the packing element.

It will also be noted that each of the coils or sections 270a, 2705 270n of the upwardly facing spiral shoulder 270 of the packing element is longitudinally spaced from the outer coils or sections of the shoulder in the same manner as are the longitudinally spaced external upwardly facing shoulders of the packing element 34 used in the wire line strippers 10 and 150.

It will also be apparent that the coils of the spring member move downwardly progressively sequentially to displace outer portions 273a 27311 of the packing element 267 radially inwardly as the wear of the packing element 267 progresses in substantially the same manner as the pistons of the wire line strippers 10 and sequentially and progressively displace the outer portions of the packing element 34 radially inwardly as the wear of the packing element 34 continues.

It will now be seen that the packing elements 34 and 267 are each disposable in the tubular body of a wire stripper and that each packing element has a plurality of longitudinally spaced external shoulders, such as the shoulders 41, 42 and 43 of the packing element 34 and the coils or sections 270a, 2701) 27011 of the shoulder 270 of the packing element 267, and that such shoulders of the two packing elements are engageable by a plurality of sequentially movable means, such as the pistons of the wire line strippers 10 and 150 and the coils 275b, 2750 27512 of the spring or operator member 275 of the wire line stripper 250, which successively and progressively displace the longitudinally aligned outer portions of shecessively smaller diameter of the packing elements radially inwardly as the packing element wears or is consumed at the area of its contact with the wire line moving through the longitudinal passages thereof.

It will further be seen that the force which moves the packing elements of the invention into sealing engagement with the wire line movable through the longitudinal passages thereof, is applied to the packing element at longitudinally spaced locations of the packing element and about the complete outer surface thereof, as at the anl9 V nular shoulders 41, 42 and 43 of the packing element 34 and the sections or coils 270a, 27Gb 270m of the shoulder 270 of the packing element 267, so that the packing elements engage the wire line with substantially uniform force throughout the length of the area of contact thereof with the wire line.

It will further be seen that each of the three ditferent wire line strippers includes a tubular body having a longitudinal passage through which a wire line may move longitudinally, a resilient or plastic packing element disposed in the passage of the tubular body and having a longitudinal passage through which the wire line may pass, and force transmitting or applying means, such as pistons or a spiral spring member, engageable with the packing element at longitudinally spaced locations which are movable in the body to compress and force the packing element into sealing engagement with the Wire line and also to sequentially and progressively displace outer portions of sequentially smaller diameter of the packing element radially inwardly as the wear of the packing element at its area of contact with the wire line reduces the amount or volume of the packing element.

While the illustrated and described spring member of the wire line stripper 250 employed to engage the spiral shoulder 270 of the packing element 267 is rectangular in cross-sectional configuration, it will be apparent that such spring member may be of other cross-sectional configurations. For example, the spring member 375 illustrated in FIGURE 7 is channel shaped in cross-sectional configuration having a vertical web 376 and laterally outwardly extending spaced flanges 377 and 378. The internal surface 379 of the web is engageable with the spiral vertical surfaces 272a, 2721; 272n of the packing element 267 and the lower shoulders or surfaces 380a, 380b 380m of the lower flange 378 are engageable with the upwardly facing shoulder 264 of the lower body section of the wire line stripper 250 and the coils or sections 270a, 270b 270n of the spiral shoulder 270 of the packing element 267. The outer vertical surfaces 381!) 38in of the coils of the lower flange engage the vertical surfaces 379a, 37% 37911 of the coils of the spring member. It will be apparent that the spring member-375 functions in the same manner as the spring member 275 but is compressible to its collapsed condition by a lesser longitudinal force applied thereto than that necessary to collapse the spring member 275 since its resilient force with which it resists deformation is smaller, .it being apparent that a solid rectangular member has a greater rigidity than a channel shaped member of the same dimensions and material.

' The spring member 475 illustrated in FIGURE 8 may also be used in place of the spring member 275 and is of triangular shape having an internal vertical surface 476 whose coils or turns 476a, 476b 47611 are engageable with the spiral vertical surfaces 272a, 2721; 27211 of the packing element and whose lower shoulders or surfaces 477a, 477b, 4770 477n are engageable with the upwardly facing shoulder 264 of the wire line stripper 250 and the coils or sections 270a, 270k 27011 of the spiral shoulder 270 of the packing element 267.

The external lower edges 478b 47811 of the coils of the, spring member are slidingly engageable with the coils or turns 476a, 476b 476n of the vertical surface 476 of the spiral member. The force necessary to collapse the spring member 475 is of course smaller than that needed to collapse the spring member 275 since the crosss ectional area of the solid spring member 475 is considerably smaller than that of the solid spring member 275 which is thus more rigid.

The foregoing description of the invention is explanatory only, and changes in the details of the construction What is claimed and desired to be secured by Letters Patent is:

1. A packing element for use in a wire line stripper having a tubular body having a longitudinal passage and a stop shoulder ex-tending laterally outwardly of and about said passage and a plurality of packing element engageable means disposed for limited longitudinal movement in the tubular body, said means having stop shoulders facing said shoulder: said packing element being of a deformable substance and positionable in the tubular body, said packing element having a longitudinal passage for receiving a wire line movable longitudinally through the longitudinal passage of the body, said packing element having a plurality of longitudinal portions of progressively smaller external diameter providing a plurality of longitudinally spaced external shoulders and an end shoulder facing oppositely from said external shoulders, said shoulders of said packing element extending about said longitudinal passage of'said packing element, the shoulders of the packing element engageable means being engageable with said external shoulders of said packing element and the stop shoulder of the body being engageable with said end shoulder of said packing element when said packing element is disposed in the tubular body, whereby longitudinally aligned outer portions of successively smaller diameter of said packing element are displaced radially inwardly by the packing element engageable means upon longitudinal movement of the packing element engageable means in the tubular body toward its stop shoulder as the packing element wears at the area of contact thereof with a wire line moving through the longitudinal passage thereof.

2 The packing element of claim 1, and a pair of guide means secured to said one end surface and one of said external shoulders most remote from said one end surface, said guide means extending longitudinally outwardly in opposite directions from said end surface and said one of said shoulders and having longitudinal passages aligned with said longitudinal passage of said packing element, said guide means guiding movement of a wire line through said packing element, said packing element having a longitudinal slit through which a wire line is movable into said longitudinal passage, each of said guide means comprising a pair of sections disposed on opposite sides of said slit.

3. The packing element of claim 2, wherein said slit extends diametrically completely through said packing element whereby said packing element comprises two separate sections, each of said packing elements having one section of each of said guide means secured thereto.

4. A packing element for use in a wire line stripper having a tubular body having a longitudinal passage and a stop shoulder extending laterally outwardly of and about said passage and a plurality of packing element engageable means disposed for limited longitudinal movement in the tubular body, said means having shoulders facing said stop shoulder: said packing element being of a deformable substance and positionable in said tubular body, said packing element having an end surface engageable with said stop shoulder of said body for limiting movement of said packing element longitudinally in one direction in the body, said packing element having a longitudinal passage for receiving a wire line movable longitudinally throughthe body, said packing element having a plurality of longitudinal portions of progressively smaller external diameter extending longitudinally away from said end surface and providing a plurality of longitudinally spaced external annular shoulders, said external annular shoulders being concentric with said longitudinal passage of said packing element, the shoulders of the packing element engageable means being engageable with said external shoulders of said packing element whereby outer portions between said external shoulders and said end surface of successively smaller external diameter of said packing element are displaced radially inwardly by the packing element eng ageable means upon longitudinal movement of the pack ing element engageable means toward the shoulder of the body asthe packing element wears at the area of contact thereof with a wire line moving through the longitudinal passage thereof.

5. A packing element for use in a wire line stripper having a tubular body having a longitudinal passage and a stop shoulder extending laterally outwardly of and about said passage and a plurality of packing element engageable means disposed for limited longitudinal movement in the tubular body, said means having shoulders facing said stop shoulder: said packing element being of a deformable substance and positionable in said tubular body, said packing element having an end surface engageable with the stop shoulder of the body for limiting movement of said packing element longitudinally in one direction in the body, said packing element having a longitudinal passage for receiving a wire line movable longitudinally through the body, said packing element having a plurality of longitudinal portions of progressively smaller external diameter extending longitudinally away from said end surface and providing a plurality of longitudinally spaced external annular shoulders facing away from said end shoulder, one of said external shoulders being spaced from said end end surface -a distance more than one-third and less than one-half the total length of said packing element and another of said shoulders being spaced from said end surface of said packing element a distance more than threefifths and less than seven-eighths of the length of the :packing element, the shoulders of the packing element engageable means being engageable with said external shoulders of said packing element whereby outer portions between said external shoulders and said end surface of successively smaller external diameter of said packing element are displaced radially inwardly by said packing element engageable means upon longitudinal movement of the packing element engageable means toward the stop shoulder of the body as the packing element wears at the area of contact thereof with a wire line moving through the longitudinal passage thereof.

6. A packing element for use in a wire line stripper having a tubular body having a longitudinal passage and an annular stop shoulder extending laterally outwardly of and about "said passage and a plurality of packing element engageable means disposed about said longitudinal passage for limited longitudinal movement in the tubular body, said means having annular shoulders facing the stop shoulder, said packing element being of a deformable substance and positionable in said tubular body, said packing element having one end surface engageable with the stop shoulder of the body for limiting movement of said packing element longitudinally in one direction in the body, said packing element having a longitudinal passage for receiving a Wire line movable longitudinally through the body, said element having a longitudinal slit from the exterior thereof to said longitudinal passage through which a wire line is movable into said longitudinal passage, said packing element having a plurality of longitudinal portions of progressively smaller external diameter extending longitudinally away from said one end surface and providing. a plurality of longitudinally spaced external annular shoulders of progressively smaller diameters, one of said external shoulders being spaced from said one end surface a distance more than one-third and less than onehalf the total length of said packing elementand another of said shoulders being spaced from said one end surface of said packing element a distance more than three-fifths and less than seven-eights of the length of the packing element, the external shoulder of said packing element of smallest diameter constituting an end surface of said packing element remote from said one end surface, the shoulders of the packing element engageable means being engageable with said external shoulders of said packing element whereby outer portions of said packing element between said external shoulders and said one end surface of successively smaller external diameter are displaced radially inwardly by the packing element engageable means upon longitudinal movement of said packing element engageable means toward the stop shoulder of the body as the packing element wears at the area of contact thereof with a wire line moving through the longitudinal passage thereof.

7. A packing element for use in a wire line stripper having a tubular body having a longitudinal passage and a stop shoulder extending laterally outwardly of and about said passage and a plurality of packing element engageable means disposed about the longitudinal passage for limited longitudinal movement in the tubular body, said means having shoulders facing said shoulder: said packing element being of a deformable substance and being positionable in said tubular body, said packing element having a one end surface engageable with the stop shoulder of the body for limiting movement of said packingelerherit longitudinally in one direction in the body, said packing element having a longitudinal passage for receiving a wire line movable longitudinally through the body, said packing element having a plurality of longitudinal portions of progressively smaller external diameter extending longitudinally away from said one end surface and providing a plurality of longitudinally spaced external annular shoulders, said shoulders constituting sections of an external spiral shoulder extending about said body of said packing element, said spiral shoulder increasing in external diameter toward said one end surface from an end of the packing element remote from said one end surface, the shoulders of said packing element engageable 'means' being engageable with said external shoulders of said packing element whereby outer portions between said external shoulders and said one end surface of successively smaller external diameter of said packing element are displaced radially inwardly by the packing element en'gag'eable means upon longitudinal movement of the packing element engageable means toward said stop shoulder of the body as the packing element wears .at the area of contact thereof with a wire line moving through the longitudinal p'assage thereof.

8. A wire line stripper including: a tubular body having a longitudinal passage therethrough and an internal stop surface extending laterally outwardly of and about said passage; a packing element disposed in said body having .a longitudinal passage through which is movable a wire line extending through said longitudinal passage of said body, said packing element having an end surface engageable with said stop surface of said body for limiting movement of said packing element in one longitudinal direction in said body, said packing element having a plurality of longitudinally spaced external shoulders; a plurality of means engageable with said external shoulders of said packing element and movable longitudinally in said body, said means displacing radially inwardly outer portions of said packing element located between said shoulders and said end surface upon longitudinal movement of said means in said one direction; and means for moving said means in said one direction in said body.

9. A wire line stripper including: a tubular body having a longitudinal passage therethrough and an internal stop' surface extending laterally outwardly of and about said passage; a packing element disposed in said body having a longitudinal passage through which is movable a wire line extending through said longitudinal passage of said body, said packing element having an end surface engageable with said stop surface of said body for limiting movement of said packing element in one longitudinal direction in said body, said packing element having a plurality of longitudinally spaced external shoulders; a plurality of means engageable with said external shoulders of said packing element and movable longitudinally in said body, said means displacing radially inwardly outer por- 23 tions of said packing element located between said shoulders and said end surface upon longitudinal movement of said means in said one direction; meansbiasing said means to positions remote from said stop surface; and means for moving said means in said one direction in said body.

10. A wire line stripper including: a tubular body having a longitudinal passage therethrough and an internal stop surface extending laterally of and about said passage; a packing element disposed in said body having a longitudinal passage through which is movable a wire line eX- tending through said longitudinal passage of said body, said packing element having an end surface engageable with said stop surface of said body for limiting movement of'said packing element in one longitudinal direction in said body, said packing element having a plurality of longitudinally spaced external shoulders, each of said external shoulders being of smaller external diameter than the next adjacent external shoulder less remote from said end surface of said packingelement; and a plurality of telescopical means disposed in said body and having shoulders engageable with said external shoulders of said packing element, said telescopical means being movable longitudinally in said body and relative to one another in said one direction for displacing radially inwardly outer portions of said packing element located between said shoulders and said end surface; and means for progressively and sequentially moving said telescopable means toward said stop surface.

11. The wire stripper of claim wherein said external shoulders of said packing element comprise sections of a continuous spiral shoulder of said packing element and said plurality of telescopical means comprise coils of a spiral spring member, said means for moving said telescopical means toward said stop shoulder including a piston movable longitudinally in said body and engaging an end surface of said spring member remote from said stop surface, one opposite end surface of said spring member engaging said stop surface.

12. A wire line stripper including: a tubular body having a longitudinal passage therethrough and an internal stop surface extending laterally outwardly of and about said passage; a packing element disposed in said body having a longitudinal passage through which is movable a wire line extending through said longitudinal passage of said body, said packing element having an end surface engageable with said stop surface of said body for limiting movement of said packing element in one longitudinal direction in said body, said packing element having a plurality of longitudinally spaced external shoulders, each of said external shoulders being of smaller external diameter than the next adjacent external shoulder less remote from said end surface of said packing element; and a plurality of tubular pistons mounted in said body for longitudinal telescoping movement relative to each other, the outer of said annular pistons having a shoulder engageable with a first of said external shoulders located nearest said end surface, said outer piston being movable external shoulder, said intermediate piston being movable in said one direction to displace radially inwardly portions of said packing element located between said second external shoulder and said end surface; and an inner piston telescopical in said intermediate piston and having means engaging an end shoulder opposite said one end surface of said packing element; and means for introducing fluid pressure into said body to move said pistons in said one direction. e i 13. The wire stripper of claim 12 wherein said pistons have surfaces exposed to said fluid pressure of such relative areas that movement of said intermediate piston in said one direction relative to said outer piston does not take place until said outer piston reaches the limit of its longitudinal movement in said one direction and movement of said inner piston relative to said intermediate piston does not take place until said intermediate piston reaches the limit of its movement in said one direction.

14. The wire stripper of claim 13 wherein said pistons are provided with coengageable means for causing said intermediate piston to move with said outer piston during movement of said outer piston in said one direction and for causing said inner piston to move with said intermediate piston during movement of said intermediate piston in said one direction, said coengageable means limiting movement of said inner piston relative to said intermediate piston and of said intermediate piston relative to said outer piston during movement of said inner and intermediate pistons in a direction opposite said one direction. 15. The wire "stripper of claim 14, and means biasing said inner piston in a direction opposite said one direction.

16. The wire stripper of claim 13; and a first means biasing said outer piston for movement in a direction opposite said one direction; a second means biasing said intermediate piston in a direction opposite said one direction; and coengageable means on said intermediate and inner pistons limiting movement of said intermediate piston relative to said inner pistoii in a direction opposite said one direction whereby said second biasing means is effective to move both said inner and intermediate pistons.

17. A wire stripper including: a tubular body having a longitudinal passage therethrough and an internal stop surface extending laterally outwardly of and about said passage for limiting longitudinalmovement of a packing element positionable in said body; a plurality of means telescopical relative to one another upon longitudinal movement thereof in the body and having surfaces facing said stop surface spaced longitudinally of said body and movable toward said stop surface whereby a packing element positioned in said body between said stop surface and said surfaces of said telescopical means is compressed between said surfaces and said stop surface upon movement of said telescopical means toward said stop surface, said surface of each of said, telescopical means being of smaller external radius than the surfaces of a telescopical means initially positioned nearer said stop surface; and means for moving said telescopical means in said one direction in said body. a

References Cited by the Examiner UNITED STATES PATENTS 2,212,040 8/1940 Parrish 16683 SAMUEL B. ROTHBERG, Examiner.

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Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3375013 *20 Sep 196526 Mar 1968King Oil ToolsFluid-actuated wiper apparatus
US3917293 *26 Jun 19744 Nov 1975Hydril CoControlled closing pattern packing unit for blowout preventer
US3947044 *7 Jul 197530 Mar 1976Bralorne Resources LimitedSecondary sealing device
US4386783 *26 Aug 19817 Jun 1983Otis Engineering CorporationPacking nut and stuffing box for hydraulic or manual actuation
US4637505 *28 Jun 198520 Jan 1987Luk Lamellen Und Kupplungsbau GmbhFluid-operated clutch disengaging apparatus
US4712772 *2 Nov 198415 Dec 1987Negrutsky Sergei BPower hydraulic gear
US4718487 *31 Mar 198612 Jan 1988Hydrolex, Inc.For wireline control equipment
US6588502 *24 Apr 20018 Jul 2003Baker Hughes, IncorporatedWell pressure activated pack-off head
US6953085 *17 Apr 200311 Oct 2005Baker Hughes IncorporatedWell pressure activated pack-off head
US8443878 *11 May 201021 May 2013Hunting Energy Services, Inc.Dual stripper assembly for slick cable
US20110017444 *11 May 201027 Jan 2011Hunting Energy Services, Inc.Dual Stripper Assembly for Slick Cable
Classifications
U.S. Classification277/330, 277/529, 277/522, 277/512
International ClassificationE21B33/08, E21B33/02
Cooperative ClassificationE21B33/08
European ClassificationE21B33/08