US2360577A - Swab rubber - Google Patents

Description

Oct. 17, 1944. B. E. PARRISH 2,360,577

SWAB RUBBER i Filed June 15, 1940 2 sheets-sheet 1 'IISIl/r/ SWAB RUBBER Y.

2 Sheets-sheet 2 Ocf- 17, 1944- B E. PARRISH FiledJune 15, 1940 Patented Oct. 17, 1944 YUNITED- STATES PAT'l' ".NTY

'FFCE SWAB RUBBER Benjamin E. Parrish, Dallas, Tex.

Application June 15, 1940, Serial No. 340,722

Claims. (Cl. 10S-225) This invention relates to new'and useful improvements in swab rubbers.-

Thisapplication. is filed as an improvement on: the swabA rubbery disclosed in UnitedV States Letters PatentNo. 2,201,451, issued to me on May 21, 1940, and asa continuation-impart of my copendingv application on swab. rubbers, filed4 J anuary 9, 1939, Serial No, 249,939, which isv now abandoned.

One object of the invention-isV to provide an improved packing; element for awell swab having all of the advantages of the packing element disclosed in my copending applications andwhich is so constructedy that distortion-of the same. into engagement with the well casing is assured.4

A particular object ofk the inventionis to provide an elastic swabA element whichis constructed so as to be distorted into :sealing position by the weight of the fluid being lifted by said swab;

Another object ofthe invention .iseto provide an improved elastic packing element for a well swab arranged to be distorted into sealing position and having auxiliaryl means adapted ,tofbe acted upon byv iiuid thereabove for, aiding such distortion to assure positive sealing-engagement of the outer surface of the element with thewellfcasing.

An important object of the invention is to provide an improved packing element for a .well swab having. an annular, exible lip formed in its upper surface, whereby upward movement of the swab will cause theflexiblellip to be distorted by the weight of the uids thereabove soas to aid the distortion of the packingk element into'sealing engagement with the well casing, said lip being reinforced by suitable radial ribs.

A further objectof the invention is to provide an improved packing element for a well swab having a plurality of recesses. orpockets in its upper surface, whereby when the swab is in lifting position the element will. be distortedl into engagement with ther well casing, such distortion being materially aidedby the action of the fluid above the element on the recesses in said element.

Still another object offtheinvention is toiprovide an improved splitv swab rubberhaving: a plurality of inwardly inclined cylindricalrecesses formed in itsv upperend, whereby uidab'ove the rubber may act thereon. toi aidin-distorting the same into its sealing position.

A still further object ofi thev invention is to provide a split swab rubber, ofV the'character described, which,- is arranged" to be:Y mounted` upon a supportingA mandrel and, has` verticalv lips; or rib formed onthe inner surface thereof adapted to slidably engage within diametrically-opposed channels or grooves extendingvertically in the exterior ofthe mandrel, the distortion of the rubber into packing-off position tending to urge the lips into sealing engagement: with their channels,` whereby said ylips* increase the lsealing action of said rubber relative tothe'mandrelias well as prevent displacement of the-rubber.

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

The invention willbemorereadily understood from-a reading of the following specification and by referencek to the accompanying drawings, in which anJ example ofthe invention is shown, and

wherein: Y

Figure 1 isl an. elevation: of a swabhaving a swab rubber, constructedin accordance with the invention, mounted .thereon,

Figure. 2 isv anY enlarged, transverse, Vertical, sectional view of one of the swab rubbers,l

Figure 3 is a transverse, vertical, sectional view of the lower portion of the swabshowing the mandrel in elevation,-v

Figure 4 is a horizontaL-crosssectional view, takenl on the'line 4,-4 of Figure 1,

Figure 5 is ahorizontal, cross-sectional view, taken on the line 5.-5of Figure 1,.

Figure 6 is an isometric. View of one section or unit of the swab rubber,

Figure Tis a view', similar to Figure 1, of. amodifled form of the swab,

Figure 8 is a horizontal, cross-sectional View, taken on the line 8 8 of Figure ,7,

Figure 9 is-a View, similar` toFigure 3, of the modified swab,.

Figure 10 is an isometric viewof this form of the swab rubber; I Y Figure 11 is a transverse, vertical, sectional view-of another form ofthe swab rubber, and

Figure 12 is a ksimilar View, of still another form of the swab rubber.`

In the drawings, the numeral HlV designates a mandrel which is preferably made of. a.r solid piece of metal, or othersuitablematerial. The mandrel is substantially cylindrical in cross-.section-and has itsv upperrendl screw-threaded withinna;; cylindrical box Ilv which is providedv with upwardly extending pin I2, preferably made integral therewith. Thepin is of such size as to receive' the standard coupling or box (not shown) of the rusual well' rod, whereby the mandrei may be readily connected to said rod and lowered. intothe well casing A. The lower end of," the-mandrel has'a cap or nut I3 threaded thereon and said nut has its end rounded so that the lowering of said mandrel into a fluid is facilitated.

A 'flexible or elastic packing element I4 is mounted on the mandrel and is constructed of two halves or units I5 and I6 which are semicircular in cross-section and are arranged to engage around the mandrel, as is clearly shown in Figure 3. Both units are exactly alike so that when they are positioned in horizontal alinement with each other they form an annular packing element. The unit I5 is slidable Vertically throughout the length of the mandrel III, while the unit I6 is mounted in a fixed position at the lower end of said mandrel as will be hereinafter' explained. With this arrangement, the unit I5 may be displaced vertically out of horizontal alinement with the other unit I6.

Since each unit is exactly like the other, a description of one will suffice. Each unit includes an elastic or resilient packing member I1 which is substantially semi-circular in crosssection and which has its outer surface tapered inwardly at its upper and lower ends. The upper end of the packing member is adapted to fit within the recess I8 of a thimble I9. The thimble is substantially semi-circular in cross-section and is arranged to snugly t the outer surface of the cylindrical mandrel.

For fastening the upper end of the packing f member within the recess I8 of said thimble, said packing member is formed with a radial opening 2|] which is in alinement with an opening 2| formed in the inner wall of the thimble (Figure 4). The outer wall of the thimble is formed with a reduced opening 22, the inner end of which is enlarged to the diameter of the openings 26 and 2I, whereby an internal annular shoulder 23 is formed in the outer wall of said thimble. It is noted that the openings 2I, 26 and 22 are in alinement with each other. After the upper end of the packing member I1 has been inserted into the recess I8 of the thimble I9 and before the unit is placed around the mandrel, a pin 24 is inserted into the openings from the inside of said thimble. This pin fits snugly within the openings 2I and 20 and the enlarged portion of the opening 22.

The extreme outer end of thepin is reduced as shown at 24a so as to fit within the reduced opening 22. The offset or shoulder formed on the pin abuts the internal annular shoulder 23 in the outer wall of the thimble, whereby outward movementk of the pin is prevented. When the unit is mounted on the mandrel I0, the inner end of the pin engages the outer surface of said mandrel, whereby inward displacement of the pin is prevented. When it is desired to remove the pin, it is merely necessary to remove the unit from the mandrel and push the pin inwardly out of the openings.

The lower end of the packing member I1 is inserted within the recess 25 of a thimble 26, which is identical in construction to the upper thimble. The lower end of the packing member is retained within the lower thimble by a pin 21, identical to the pin 24. As is clearly shown in Figure 2, the inner surface of the packing member has its intermediate portion projecting radially inwardly, whereby said intermediate portion is of materially greater thickness than the ends of said member. Obviously, this enlargement of the intermediate portion of the member I1 provides an internal, arcuate shoulder 28 at the top of said member and a comple- CTI mentary shoulder 29 at its bottom which are engaged by the ends of the inner walls of the thimbles I9 and 26 (Figure 3). Thus, the inner surface of the intermediate portion is flush with and forms a continuation of the inner walls of the thimbles.

An inwardly-inclined recess or groove 30, which is arcuate or semi-circular in cross-section, is formed in the upper, inwardly-tapered surface of the packing member adjacent its external straight wall, whereby an arcuate wall or lip 3I is provided at the intersection of said tapered surface and straight wall. The lip 3I is iiexible and may be reinforced by a plurality of radial ribs or webs 32 which extend across the recess and downwardly to the bottom thereof so as to divide the same into a plurality of equispaced pockets or openings 33. The provision of this lip in the upper end of each packing member tends to materially aid the distortion of said members. Upon the upstroke of the mandrel II) and the units I5 and I6 ofthe packing element I4, the lips 30 of the packing members I'I of said units will be exposed to the weight of the fluid or liquid being lifted, whereby the iluid may act on the members to distort the same into engagement with the inner surface of the casing A. The increased distortion of the members by the fluid also increases the contact between the engaging vertical inner faces of the members to assure a huid-tight seal therebetween.

For slidably mounting the unit I5 on the mandrel I0, a pair of diametrically-opposed channels or keyways 34 are provided in said mandrel and extend vertically throughout the length thereof. Each thimble I9 and 26 is provided with an inwardly projecting pair of ribs or keys 35 which are located at the inner surface thereof. The ribs or keys are adapted to slide within the channels or keyways 34 of the mandrel and, obviously, prevent displacement of the unit from said mandrel. In mounting the man- M drel, it is only necessary to remove the nut I3 at the lower end thereof, and to slide the unit upwardly on said mandrel, whereby the keys 35 engage the channels 34. The nut is then returned to the lower end of the mandrel and it will be seen that the unit I5 is confined to a vertical movement between said nut and the box I I at the upper end of said mandrel.

The unit I6 is constructed exactly as is the unit I5 and is mounted on the mandrel in a similar manner. However, the inwardly projecting ribs or keys 35 of the thimbles of this unit engage indiametrically-opposed grooves or keyways 36. `The length of the grooves 36 is less than the length of the channels 34, being substantially the Vertical length of the unit I6. Thus, the grooves or keyways 36 extend from the lower end of the mandrel to a point opposite the upper end of the unit I6. It is pointed out that the grooves 36 extend contiguous to the channels 34 and, therefore, the lower ends of the latter are combined with the former to provide a comparatively wide recess at the lower end of the mandrel.

A pair of diametrically-opposed lips or ribs 3l, similar to the ribs 35, are preferably made integral with the interior of each packing member I! at its intermediate portion as shown in Figure 5, The internal lips of each packing member are vertically alined with the ribs of its respective thimbles I9 and 26 and are arranged to engage Within the keyways of the mandrel to prevent and the` mandrel, andi particularly. the. keyways Since the groovesz terminate. at: the upper end of'v the unitIBf, it will ,be seen thatthe uppermost. thimbile of saidiunit. will abutthe upper end of'said grooves. It will beheld in this-position bythe engagement ofthe nut. I3:with its lower end, whereby the unit. is mountedin a fixed position on the :mandreland incapable of' movement with relation thereto ySince the` channels 34 within which the unit I5` is. slidableV extend throughoutithe length of the mandrel; it will be evident that this unit' mayvsl-ide verticallyy with relation to the unit lliwhich is attachedin xed position on saidmandrel. Although-it has been found practical to mount the units in the manner above described,- it isV pointed? out that' other methods of'mounting said units on the-mandrel may be employed. The particular mounting of the units forms vno part of the present invention and is, therefore, subject to variation.

In operation, the assembly is secured tov a string of sucker rods orl other lowering device (not shown) and is lowered into the well casing. A with the parts in the position shown in'rFigures 1 and 3. As soon as the assembly strikes the uid within the casing, the resistance of said fluid together with the frictionalengagement of the packing member I1 of the unit I5 with the well casing A will immediately raise said unit I5 on the' mandrel, the -keys 35 on the thimbles of said unit sliding upwardly in the diametrically-opposed channels 34. The mandrel isV of; such length as to permit the unit I5 to move upwardly to the position shown in dotted lines in Figure '1, whereby the lowerend of saidunity will be above the upper end of the unit IE.' Manifestly, this displacement of the movable unitout` of .h ori zontal -alinement withY the stationary unit acts as aA valve to permit by--passing of the fluid on the downstroke ofthe device. ofcourse, if vthere is` any fluid pressure within the casing A, the samewill raise the unit I5 to its upper position.

When the assembly has-reacheditslowerrnost position and the raising. operation hasbegun, Athe weight and pressure of the iiuidabove the assembly will immediately act upon the elevated unit I5 to lower the same. This unit will,.vof course, immediately move downwardly on the mandrel until the lower ends of its thimble 2,6

rest upon the nutIS. In this position, the unit I5 is opposite the stationary unitlland the fluid will then act uponboth unitstoforce the, thirnbles I9 thereof downwardly toward the thimbles. 2 5', whereby the resilient or elastic packingA members I1 are 'distorted outwardly into engagement with the inner wall of the well casing- A. This distortion of the packing members is aidedlby. the lip 30 formed in theupper end of each member. The fluid above the. packing members, will. enter the pockets or openings. 3.3and thevweightA or downward pressure of said fluidfwill be exerted against the lip and webs 32 whichform the Awalls of. said pockets so as to enlarge or expand the size of the same, whereby the porti-on of each packing member surrounding the arcuate recess` 30 thereof will be displaced or. distorted, with the result that the lips of sai-d memberswill move outwardly into engagement with thecasing. This distortion of the packing members will also cause the inner surfaces of said members to move radi-y bers. beyond their: elastici limits.

ally;inward-lyY into engagement; withV the mandrel;r and', particularly the vlips.-` 3 1 whichl are disposed inthe keywaysof saidj'mandrel; Thus; the lips provide an-auxiliary-f means; upon which the fluid may-act to assure a positive frictional engagement between the casing and packing members, as; well as'between themandrel and` said members; Continued upward-movement of the assembly after the packingA members IIvr haveLv moved into engagement with the casing-will lift the fluid above the packing element, I4 and, at the same time, the inner.` wall of; said easingwill be swabbed.

InFiguIesto l0,= amodied form ofthe invention.- is shown andincludes an elastic or resilientpacking member 3.8 which-is si-milartoA the packing member I'I-. 'Ehememberzis substan tiall-y serniecircular: in' cross-section. and has its. exterior Vtapered atits upperl and, lower ends, while its entire inner surface-or` wall is disposedin ay Vertical plane. Aplurality.y of.- cylindrical recessesy or pockets 39 are provided inthe upper inwardly--Y tape-red Ysurface of; the packing member. The recesses .3'9 are spaced-anequi-distance apart and are.y inclined -v inwardly anddovsrnwardly.,` as,` is clearly I shown in Figure 9.` The recesses do not extend entirely through .the member 38g butlhaye their. inner ends terminating. atsubstantially` the centralportion. thereof or midway.` between the. inner andouter surfaces ofsaidzmember. It is readilyI apparent that; these inclinedrecessesare exposed toK the fluid abovethe member and aid the distortion of said` member intopacking position. l

A,radial openingr, similarto the openingl 20,Y is. providedv at the upper andlowerends of eac-h packing member 381 sothat it maybe fastenedto thefthimbles 4I dhd42. 'I fhese thimblesmay. be similar to the thimbles I9and,.26.but..are, pref- Y erably, formed inaccordance with the .disclosures of' my copending applicationsywhichlhave been hereinbeforeset.` forth- The: inner wall of the upper thimble. 4I is extended downwardly; to form a projecting skirt 43,'while a similar skirtv 44. is provided.. by upward.extensionofy the inner wall ofthe4 thimbleAZ.. `The .skirts 4 3vv and Mextend contiguous to theinner. wall ofthe packing memerf when-said member is inpcsition within the thimble., It is noted that when the packing member is secured between .the thimblesA-I and 4,2., the inner ends ofI the skirts 43..and-44f. of said thimbles arespacedfrom eachother.4 This position is .clearly shown in `Eigure 9, and occurs when the packing member isin its normal y orundistorted position.

The upper. thimbles 4fIfw-il1 move' downwardly until-tbe inner: edges ofthe skirts 4-3, which project downwardly therefrom, strike the inner Vedges oftheupwardly projecting skirts 44 on the l lower thirnblesAZ.v When= this occurs, further distortion of the packing members is prevented: Therefore, .it will be seen that-theextended skirts provided on the thimbles providega positive means for preventing. afdistortion ofthe packing` mem- However, the uid .may continue :to .act vupon lthe packing membersfthrough the recessesgto distort'said members independently of the thimbles.

Therecessesorpockets 39fserve the same purposeas the flexible lip-3Iof the member- I'I.in thatfthey tendto aid-the distortion of `the member. 3,81 When-afwell swab having packing membersof this type is. used to raise a, fluid, the pres-v sure or weight of saiduid will .be exertedfag-ainst the walls, ofthe recesses of said memberst wheref member by the portion of the members surrounding said recesses will` be displaced to increase the distortion of said members. Therefore, it is obvious that distortion of the packing members 38 into engagement with the inner wall of the casing is assured.

Another form of the invention is disclosed in Figure 11 and includes a resilient or flexible packing member 45 which is substantially semi-circular in cross-section and which has its outer surface tapered at its upper and lower ends. At the intersection of the upper tapered surface with the outer straight wall of the member, a shoulder or lip 46 is formed, being preferably made integral with said member and being exposed around the outer surface thereof. The shoulder is inclined inwardly and downwardly and, obviously, is exposed to the fluid thereabove. The member 45 is similar to the member 38 and is formed with a radial opening 41 at its upper and lower ends, whereby said member may be secured to the thimbles 4| and 42,

It is manifest that the inclined shoulder 4B is provided for the same purpose as the lip 3| and recesses 39 of the other packing members and increases the distortion of the member 45, since the pressure or weight of the fluid above said member is exerted thereupon. Thus, a uid-tight seal between the packing members and the internal surface of the well casing is assured.

In order to increase the flexibility of the packing element I4, and particularly the mid-portion thereof, so as to facilitate the passage of said element past the couplings of the casing A, a slightly modified form of packing member 48 (Figure 12) may be substituted for the packing Il. The member 48 is substantially semi-circular in cross-section and has its outer surface tapered inwardly at its upper and lower ends. The general appearance of this member is very similar to that of the member II and thev same is formed with a radial opening 49 at each end so that it may be secured to the thimbles I9 and 26.

An arcuate groove or recess D, similar to the recess 3U, is formed in the upper inwardly-tapered surface of the member 48 adjacent its external straight wall, whereby an arcuate lip 5I, similar to the lip 3|, is provided at the intersection of said surfaces. The rear or inner wall of the recess 5i) is disposed in a vertical plane and extends from the upper end of the packing member downwardly past the central portion thereof and terminates at a point in substantially the same horizontal plane as the intersection line between the straight and lower tapered surfaces of said member. Thus, the lip 5| is composed of substantially the entire external mid-portion of the member 48 and is considerably much more flexible than the lip 3|. This flexible lip may be reinforced by a plurality of radial ribs or webs 52 which extend across the recess 50, upwardly to the top of the member and downwardly to the bottom of said recess, thereby dividing the latter into a plurality of equi-spaced pockets or openings 53. The lip 5| not only tends to materially aid the distortion of the member 48 but also increases the flexibility of the same, whereby the passage of the packing element I4 past the casing couplings is facilitated. The inner surface of the packing member is identical to that of the member I1 and the intermediate portion thereof may be provided with suitable lips (not shown) for engaging within the keyways of the mandrel.

It is pointed out that, if desired, the packing lll member 45, as well as the packing member v38, could be made in the same manner as the packing members Il and 48 so that they could be mounted on the thimbles I9 and 26. In this event, the members 38 and 45 would be provided with the internal ribs or lips 31 of the members I'I and 48. Conversely, the internal contour of the members I 'I and 48 could be formed complementary to the thimbles 4I and 42, whereby said member would have the same general appearance as the members 38 and 45'and could be substituted therefor.

The foregoing description of the invention is explanatory thereof and Various changes in the size, shape and materials, as well as inthe details of the'illustrated construction, may be made, within the scope of the appended claims, without departing from the spirit of the invention.

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

1. As a sub-combination in a well swab, a packing assembly including, a mandrel having vertical grooves therein, and a split elastic sealing element, the element being arranged to be distorted radially into a sealing position and having integral means for engaging the grooves of the mandrel to retain said element on said mandrel, the distortion of the element urging said means into snug engagement with said grooves so as to seal off between the mandrel and element.

2. As a sub-combination in a well swab, a packing assembly including, a mandrel having vertical grooves therein, and a split elastic sealing element, the element being arranged to be distorted radially into a sealing position and having vertical ribs for engaging the grooves of the mandrel to retain said element on said mandrel, the distortion of the element urging said ribs into snug engagement with said grooves so as to seal orf between the mandrel and element.

3. As a sub-combination in a well swab, a packing assembly including, a grooved support, and

a split elastic sealing element arranged to be distorted radially into sealing position and having integral means for engaging the grooved support to retain the element on said support, said element having a plurality of recesses exposed to and adapted to be acted upon by the fluid thereabove for increasing the radial distortion of the internal and external peripheral portions thereof.

4. As a sub-combination in a well swab, a packing assembly including, a grooved support, and a split elastic sealing element arranged to be distorted radially into sealing position and having integral elastic means forV engaging the grooved support to retain the element on said support, said element having flexible means at its external peripheral portion exposed to and adapted to be acted upon by the fluid thereabove for increasing the radial distortion of the internal and external peripheral portions thereof.

5. The sub-combination set forth in claim 4 wherein the element has means for reinforcing the flexible means, the distortion of the element urging the integral elastic means into snug engagement with the grooved support so as to seal olf between said support and the element.

6. The sub-combination set forth in claim 4 wherein the flexible means is an inwardly and downwardly inclined shoulder.

7. A packing assembly for a well swab includ` ing a pair of units arranged to be displaced out of horizontal alinement with each other to permit fluid to freely by-pass the assembly on the downstroke of the swab, each unit including an elongate elastic body portion solid in cross-section and adapted to be distorted radially into sealing position on the upstroke of said swab, a flexible lip formed on the exterior of the body portion adjacent to and below the upper end thereof and having its inner surface spaced from said body portion so as to provide a pocket therebetween, the pocket being exposedto and adapted to be acted upon by the fluid thereabove for increasing the radial distortion of the peripheral portions of the body portion, and integral means extending from the upper end of said body portion to said lip for reinforcing the latter and preventl ing excessive distortion thereof.

8. As a sub-combination in a well swab having a displaceable section, an elongate elastic member substantially semi-circular in cross-section and having its ends reduced, the member being adapted to be distorted radially into sealing position and being solid in cross-section, said member having a plurality of pockets formed in its external peripheral portion adjacent to and below its reduced upper end and terminating short of the internal surface of the member so as to be disposed intermediate the external and internal surfaces thereof, the pockets being exposed to and adapted to be acted upon by the fluid thereabove for increasing the radial distortion of said external and internal peripheral portions.

9. As a sub-combination in a well swab having a displaceable section, an elongate elastic member substantially semi-circular in cross-section and having its ends reduced, the member being adapted to be distorted radially into sealing position and being solid in cross-section, an arcuate flexible wall made integral with the external peripheral portion of said member below its reduced upper end and being spaced radially from the member so as to provide an arcuate recess therebetween, the recess being exposed to and adapted to be acted upon by the iuid thereabove for increasing the radial distortion of the internal and external peripheral portions of said member, and radial exible ribs extending from said reduced upper end to the wall and into said arcuate recess so as to divide the same into a plurality of pockets, whereby thek ribs reinforce said wall and prevent undue distortion thereof.

10. A packing assembly for a well swab including a pair of units arranged to be displaced out of horizontal alinement with each other to permit fluid to freely by-pass the assembly on the downstroke of the swab, each unit including an elongate elastic body portion solid in cross-section and adapted to be distorted radially into sealing position on the upstroke of said swab, a flexible lip formed on the exterior of the body portion adjacent to and below the upper end thereof and being disposed outwardly of said body portion so as to provide an arcuate pocket therebetween, the pocket being exposed and adapted to be acted upon by the fluid thereabove on the upstroke of the swab for increasing the radial distortion of the internal and external peripheral portions of the body portion, and radial flexible ribs extending from the upper end of said body portion to the lip and into said pocket so as to divide the same into a plurality of recesses, whereby the ribs reinforce lsaid lip and prevent undue distortion thereof.

BENJAMIN E. PARRISH.

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