US2132037A - Blow-out preventer - Google Patents

Description

Oct. 4, 1938. J. w. MaCCLATCHlE 2,132,037

BLOW-OUT PREVENTER Filed March 30, 1936 2 SheetsSheet 1 INVENTOR 16 507111 mz accla l a .15'

1 BYLRILJIW ATTORNEY.

Oct. 4, 1938. J, w, MaCcLATcI-"E 2,132,037 h BLOWOUT PREVENTER Filed March 50, 1936 2 Sheets$heet 2 INVENTOR.

J67? Mlfic (Wale,

ATTORNEY.

Patented Oct. 4, 1938 BLOW- OUT PREVENTER h .I ohn W.Maclatchie, Los Angeles, Calil., assignor to MacClatchie Manufacturing Company of California, Compton, Calif., a corporation ol California flippucation March so, 1936, Serial No. 71,632

13 Claims.

' a relativelyradially'contracted around a well string such as drillpipe or "tubing, to pack off be- 5. tween the well string. and surrounding well casng, or the pcooperating closure elements may be relatively radially expanded to clear the bore of the well casing.

. It is an object of the invention to provide 10 packing for the cooperating closure elements adapted for pressure responsive expansible distortion after the closure elements have been relatively radially contracted around a well string, whereby the packing seals tightly around the 15 well string whether the latter is circular in cross- .section, e. g. drill pipe, or is non-circular in crosssection, e. g. a square kelly.

It is a further object of the invention to relatively radially contract the cooperating closure 20 elements by fluid pressure, with the packing which is distorted for sealing engagement with the well string also forming the pistons whereby the'fiuid pressure is exerted against the cooperating closure elements.

as It is a still further object of the invention to construct the closure elements as cup packings, with the walls of the cups adapted for pressure responsive expansion to seal against the walls of cylinders in which the cooperating closure ele- 30 ments are adapted for reciprocation, in order that fluid pressure directed into the cup packings may shift the latter in their cylinders for relative radial contraction of the closure elements around a well string, and with movement of the closure 35 elements in their cylinders arrested when relatively radially contracted, whereupon the fluid pressure directed into the cup packings expan sibly distorts the bottoms of the cups to seal tightly around the well string.

40 It is a still further object of the invention to provide abutment plates cooperating with the cup packings to form the closure elements, with the abutment platesof the cooperating closure elements defining a closure for the annular space 45 between the well string and the surrounding well casing when the closure elements are in operative position, and with said abutment plates positioned beyond the cooperating cup packings in the direction of the axis of the well casing, where- 50 by distortion of the bottoms of the operatively positioned cup packings longitudinally of the well casing, as a result of pressure in the well casing, is prevented by the cup packings abutting the closure which has been formed by the cooperating abutment plates.

It is a still further object of the invention to preferably arrange the abutment plates on the cup packings both above and below the cup packings, so that when the closure elements are operatively contracted around a well string, the abutment plates define a closure both above and below the cooperating cup packings. for preventing distortion of the packing in either direction longitudinally of the well casing.

It is astill further object of the invention to secure the abutment plates to the cup packings so that the closure elements, each comprising a cup packing and one or more cooperating abutment plates, are shifted as units in their cylinders until their movement is arrested when they have reached their operative position, with the bottoms of the cup packings free for movement relative to the abutment plates so that the bottoms ofthe cups may then be expanded and distorted to tightly seal around a well string.

It is a still further object of the invention to provide operating means for relatively radially expanding the cooperating closure elements by retracting them in their cylinders from their operative to their inoperative position, and to preferably actuate said operating means by fluid pressure.

It is a still further object of the invention to provide connecting rods as a part of the operat ing means for retracting the closure elements in their cylinders, and to flexibly connect the rods to the packing cups of the closure elements so that when the operating means is actuated, the rods retract the packing cups, but when the packing cups are projected to operative position the flexible connections permit distortion of the cups relative to the connecting rods, to relieve the latter of all strain.

Further objects of the invention will be readily understood from the following description of the accompanying drawings, in which:

Fig. 1 is a front elevation of the invention.

Fig. 2 is an' axial section on the line 22 of Fig. 1.

Figs. 3 and 4 are transverse sections on the line 3-3 of Fig. 1, respectively showing the closure elements in operative and inoperative position. s

Fig. 5 is a transverse section on the line 5-5 of Fig. 3.

Fig. 6 is a transverse section on the line 6-6 of Fig. 3.

The blowout preventer is incorporated in a string of well casing l which is adapted to receive a well string 2, such as drill pipe or tubing, shown in the present instance as drill pipe having usual tool joints 2a and including a usual kelly 22); and the blowout preventer comprises cooperating closure elements I which are adapted for relative radial contraction around the well string as shown at Figs. 2 and 3. or relative radial expansion to clear the bore of the well casing as shown at Fig. 4. l

The closure elements are reciprocated in cylinders 4 to provide their relative radial expansion or contraction, the cylinders projecting radially from a housing I which is connected to proximate lengths of the string of well casing -l and which has a bore 6 forming a uniform prolongation of the bore of the well casing. The cylinders 4 open into the bore 6 and are equi-distantly circumferentially spaced around the housing 5. In the present instance the cooperating closure elements are three in number, and therefore the housing 5 go is formed with three of the radially projecting cylinders 4.

The closure element in each cylinder 4 comprises a packing cup l0 and one or more cooperating abutment plates ll. The abutment plates prevent distortion of the packing cups longitudinally of the bore 6 when the closure elements are relatively radially contracted around the well string 2, and since this distortion may be in either of opposite directions, an abutment plate ii is preferably provided both above and below the cup III as shown at Fig. 2. When the closure elements are relatively radially contracted around a well string 2, the abutment plates ll above the packing cups cooperate to define a closure means in the annular space between the well string 2 and the wall of the bore 8 for preventing upward distortion of the packing cups, longitudinally of the bore, and the abutment plates ll below the packing cupssimilarly cooperate to define a closure means in said annular space for preventing downward distortion of the packing cups longitudinally of the bore of the well casing.

Each packing cup I0 is adapted for pressure responsive shifting along its cylinder 4 until relative radial contraction of the closure elements around the well string 2 defines a closure means in the annular space between the well string and the wall of the bore 6, and shifting of the closure elements being then arrested, the fluid pressure expands and distorts the bottoms Illa of the packing cups so as to seal tightly around the well string no matter what cross-section the string may have. For this purpose each packing cup is of yieldable material and is preferably resilient, e. g. rubber or the like, and is preferably a deep cup, the wall lb of which fits snugly in the bore of cylinder 4 with the wall preferably tapering to a thin lip I00, and with the bottom Ilia of the cup of appreciable thickness and having an outer surface tapered as shown at llld, with an arcuate recess llle at the apex of the taper and having its axis parallel to the axis of the bore 6.

Fluid pressure in the cylinders 4 in back of the packing cups seals the walls of the cups against the cylinder walls and then shifts the cups in their cylinders until the tapering surfaces llid of next adjacent cups abut, the angles of the surfaces I M being such that these surfaces of the plurality of cups will abut when the pack-- ing cups have formed a complete closure around i the well string 2; and the arcuate recesses I00 of the plurality of cups are arranged so as to cooperate to define a bore at the axis of the housing 5 when the packing cups have been projected to operative position, with this bore of a size to receive the well string 2. When the cup packings have been thus operatively projected and their movement has been arrested by abutment of their surfaces llid, fluid pressure in thecups distorts and expands the bottoms of the cups as shown by broken lines at Fig. 3, in order to tightly seal the bottoms of the cups around the well string. In the present instance the-kelly 2b which forms that portion of the well string at which the seal is made, is of usual rectangular cross-section, and the bottoms Illa of the cups are adapted for such expansible distortion responsive to fluid pressure as to eifectively seal around such 9. rectangular cross-section, and therefore will seal of! the well string no matter what its cross-section may be.

The abutment plates II are shown as partially encircling the upper and lower portions of the peripheries of the packing cups, and are adapted for retraction and projection with the cups. For this purpose the upper and lower portions of the peripheries of the packing cups are arcuately recessed for some appreciable distance from the bottoms of the cups along their axial length, and the plates II are arcuate plates received in said recesses with the outer peripheries of the plates prolonging the peripheral working surfaces of the pistons which are formed by the cup packings. The outer ends of the plates ll taper as shown at lid and are recessed as shown at lie, to correspond to the taper id and the recesses Hie of the packing cups. The plates ll may be secured to the cup packings for reciprocation therewith, by providing the inner ends of the plates with internal flanges I2 which are received in arcuate slots l3 in the packing cups.

When the packing cups are shifted in their cylinders to operative position, the plates II are thus also operatively projected, and when the surfaces llid of the packing cups abut, the surfaces lld of the plates ll similarly abut for arresting further relative radial contraction of the closure elements while permitting expansible dis-' tortion of the bottoms of the cup packings to complete the seal as previously described. In practice the arcuate recesses llle.l le are preferably of such depth that when the closure elements are relatively radially contracted around the well string 2, the bore which is defined by said recesses, prior to expansible distortion of the bottoms Illa of the packing cups, is of a size to leave a restricted annular space between said bore and the well string 2 permitting passage of the kelly 2b and the tool joints 2a as shown at Fig. 2. The expansible distortion to which the bottoms Illa of the cup packings are then subjected closes this annular space so that the packing seals tight-' ly around the well string, with the annular space which still remains between the plates ii and the well string 2, of such restricted area that the plates ll will effectively prevent excessive distortion of the packing longitudinally of the bore 6.

Means are provided for retracting the closure elements within their cylinders so as to relatively radially expand them from their operative position, and said means is preferably fluid operated.

As an instance of this arrangement a cover plate l4 for the outer end of each of the cylinders 4 may have a depending extension I41: forming a cover plate for a cylinder [5 which is fixed to the cover plate so as to extend parallel to the over-lying cylinder 4, and a piston I6 is adapted for reciprocation in each of the cylinders l5. At each of the cooperating cylinders 4l5 a lever I8a is medially pivoted to a supporting arm II which may project from the cover plate I4I4a, and one end of this lever is connected to a rod I8 which is connected to the closure element 3, and the opposite end of the lever is connected to a piston rod I9 which is secured to the piston I6. When fluid pressure is supplied to the cylinder 4 and exhausted from the cylinder I 5, the closure element 3 is thus shifted in its cylinder to its operative position, thereby retracting the piston" I6 in its cylinder I5 as shown at Fig. 2, and when fluid pressure is exhausted from the cylinder 4 and is supplied to the cylinder I5, the piston I6 is projected, thereby retracting the closure element 3.

A flexible connection is preferably provided between the rod I8 and the closure element 3, whereby the rod retracts the closure element when the piston I6 is projected; but when the closure element is shifted to operative position responsive to fluid pressure in the cylinder 4, the packing cup of the closure element may distort relative to the rod I8 so as to permit sealing engagement by the packing cup with the wall of the cylinder 4 and around the well string 2, without strain on the rod I8. As an instance oi this arrangement a spider 20 may be fixed to the rod I8, with its periphery comprising a plurality of circumferentially spaced arcuate members 2|, and the members 2| are slotted for reception of tongues 22 of arcuate members 23 which are adapted for reception in arcuate grooves 24 in the inner peripheral surface of the side wall lb of the packing cup. The connections 22 and 24 secure the packing cup I0 and the rod I8 against relative longitudinal displacement for retracting the packing cup when the rod is retracted, but permit radial displacement of the side wall Illb of the packing cup with relation to the rod I8, so that when the packing cup is operatively projected responsive to fluid pressure, the pressure may radially distort the cup with relation to the rod I8 in order to insure an efiective seal, without transmitting strain to the rod I8.

Means are provided for substantially simultaneously supplying fluid pressure to the plurality ,of cylinders 4 and exhausting the plurality of cylinders I5, or exhausting the plurality of cylinders 4 and supplying fluid pressure to the plurality of cylinders I5. As an instance of this arrangement a manifold may extend around the housing 6 below the cylinders 4 and radially inwardly from the cylinders I 5, and the manifold may be provided with a pair of conduits 3I32. Below each of the cylinders 4 a pair of conduits 33-34 extend parallel to said cylinder, straddling the cylinder I 5, with the inner ends of said conduits communicating respectively with the conduits 3I32, and with the outer ends of said conduits closed by the cover plate I4I4a. Each of the conduits 33 opens into its cooperating cylinder 4 as shown at 35 and each of the conduits 34 opens into its cooperating cylinder I5 as shown at 36, and when fluid pressure is exhausted from the cylinders 4, the fluid preferably drains through the conduits 33 into the conduit 3I as shown at Fig. 1.

When fluid pressure is supplied to the conduit 3I and the conduit 32 is open to the atmosphere,

the closure elements 3 are thus shifted to operative position; and when fluid pressure is supplied to the conduit 32 and the conduit 3| is open to the atmosphere, the pistons I6 retract the closure elements 3 to their inoperative position. Pipes 3148 may be connected to theconduits 3I-32 for supplying and exhausting fluid pressure, and a valvular control 39, which may be remote from the blowout preventer, is preferably connected to the pipes, and is arranged so that movement thereof in one direction supplies fluid 31-38 respectively.

The plug or the valve has passageways 44-45 arranged so that when the plug is turned to the position shown at Fig. 3 the pipe 38 exhausts to the atmosphere and the pipe 31 is open to the fluid pressure supply, and when turned to the position shown at Fig. 4 the pipe 38 is open to the fluid pressure supply and the pipe 31 exhausts to the atmosphere.

Fluid pressure may be supplied to the port via pipe 50, and by means of branch pipe 5I-52 the fluid pressure may be supplied from the slush pumps of the drilling outfit, or may be supplied from a water service main, the branch pipes 5I-52 having valvular controls -56 whereby these sources of fluid pressure may be selectively employed. In order that the pressure supplied to the pipe 50 may be boosted, for example when utilizing fluid pressure from a water service main, a hand pump may be connected to the pipe 50 via a branch pipe 58 which is provided with a usual check valve 59.

When projecting the closure elements to their operative position, it may be desirable to independently limit movement of the closure elements without relying exclusively upon abutment of the surfaces IIlcLI Id of the cooperating closure elements, since by independently arresting movement of the closure elements when they have reached a predetermined position, it is possible to deflne a bore at the recesses IOe-I Ie which will be exactly concentric with the bore 6, and by providing such apredetermined limit for the movement of each closure element, its rod I8 and the operating mechanism for the same may be relieved of all strain when the closure element is operatively projected. As an instance of means for independently limiting movement of the closure elements, stops may be mounted on the cylinders 4 so as to engage the abutment plates II of the closure elements when the latter has been shifted to operative position, and in the illustrated embodiment wherein an upper and a lower abutment plate II is provided for each closure element, a stop preferably cooperates with each abutment plate. The stops are shown as pins 60 projecting into the bores of cylinders 4 and sliding in longitudinal grooves BI in the abutment plates II, and when the closure elements have been projected to operative position the pins 60 engage the ends of the grooves 6| for arresting movement of the closure elements.

In operation, with one or; the other of the valves 55-56 open, the valve 39.-=is turned to the position shown at Fig. 4 for projecting the pistons I8 in their cylinders I5 to retract the closure elements 3, the cylinders 4 being open to the atmosphere via port 4I during this operation. The bore of the well casing I and the prolongation thereof which is formed by the bore 6 is thus unobstructed and the well string 2 may be run in or withdrawn, and when the well string is in place the annular space surrounding the same remains unobstructed as long as the closure ele ments 3 occupy their inoperative position.

5 when it is desired to seal of! around the well string, for example when a blowout occurs or when the well is to be kept under control while running in or removing the well string, the valve 3! is turned to the position shown at Fig. 3,

10 and one or the other of the valves "-58 being open, fluid pressure is exhausted from the cylinders I and is supplied to the cylinders l for projecting the closure elements to their operative position, with movement of the closure ele- 18 ments arrested by abutment of the surfaces lid-lid of the cooperating closure elements, and by the pins 60 engaging the ends 01' the grooves ii. The closure elements thus shut oil the bore t except for the restricted bore lte-ile I through which the well string 2 extends. Continued fluid pressure exerted against the cup packings then expansibly radially distorts the bottoms Illa oi the cups so that they seal around the well string 2, with the abutment plates Ii I preventing distortion oithe packing cups longitudinally of the bore I. By regulating the fluid pressure exerted in the cylinders 4, a limited pressure may be maintained whereby the bottoms of the packing cups may radially yield from their I sealing position responsive to the radial i'orce exerted by drawing a tool Joint of the well string through the seal, with the fluid pressure retuming the bottoms of the packing cups to their sealing position as soon as the tool joint has passed;

I, or in the event of a blowout, such pressure may be maintained in the cylinders 4 as will hold the seal against any well pressure liable to be encountered.

By providing more than two of the cooperating d closure elements, each one is required to seal around less than half of the bore defined by the cooperating recesses lllel is, so that the bottoms of the cup packings may be expanslvely distorted to provide a tight seal all the way around as said bore, without subjecting any one 01 the bot toms III to excessive distortion; and by limiting relative radial contraction of the closure elements, but continuing to exert pressure against the bottoms of the packing cups, the distortion of the IQ bottoms of the cups is an expansible distortion, insuring a tight seat around the well string 2.

I claim:

1. In a packing device, a plurality of closure elements relatively radially contractible for cooperation defining a closure means surrounding a bore opening therethrough axially of said radial contraction, the portions of the closure elements which define the wall of the bore being formed of packing material, and means functioning independently oi! pressure in the bore for exerting fluid pressure against said portions of the closure oelements tor expansibly distorting e packing material for projection into the bore r sealing 55 around a member extending therethrough.

2. In a packing device, a plurality oi. closure elements each formed of packing material, and means for exerting fluid pressure directly against the packing material of the closure elements for 7 first relatively radially contracting the closure elements for cooperation defining a closure means surrounding a bore opening therethrough axially oi said radial contraction, and then expansibly distorting the portions of the packing material a Y which define the wall 01' the bore, for projection into said bore for sealing around a member extending therethrough.

3. In a packing device, a plurality oi closure elements relatively radially contractible for abutting cooperation defining a closure means' sur- 5 rounding a bore opening therethrough axially of said radial contraction, the portions of the closure elements which define the wall of, the bore being formed or packing material, and means for exerting fluid pressure against said portions 10 of the closure elements, other than directly from the bore, for expansibly distorting the packing material for projection into the bore subsequent to abutment oi the closure elements, for sealing around a member extending through the bore.

4. In a packing device, a plurality of closure elements each formed 01' packing material, and means for exerting fluid pressure directly against the packing material of the closure elements for first relatively radially contracting the closure 90 elements for abutting cooperation defining a closure means surrounding a bore opening therethrough axially of said radial contraction, and subsequent to abutment of the closure elements expansibly distorting the portions of the packing a material which define the wall oi! the bore, for projection into said bore for sealing around a member extending therethrough.

5. In a blowout preventer, a housing having a bore, more than two equi-distantly circumferenso tially spaced radial cylinders opening into the bore, closure elements in the cylinders each comprising a cup packing and arcuate abutment plates at the' peripheral surface 01 the cup adjacent the bottom of the cup, the bottom of each cup being toward the axis of the bore, the arcuate abutment plates for each cup being fixed against longitudinal displacement relative to the cup and being respectively at the upper and lower portions of the peripheral wall 01' the cup, a spider in each cup, connections between each spider and the wall or its cup fixing the spider against longitudinal displacement relative to its cup for permitting radial displacement of the wall of the cup with relation to the spider, an auxiliary cylinder for each of the first mentioned cylinders, a piston in each auxiliary cylinder, a conduit communicating with the plurality of first mentioned cylinders, a conduit communicating with the plurality of auxiliary cylinders, a valvular control for selectively supplying fluid pressure to either one of said conduits and its communicating cylinders and exhausting fluid pressure from the other of said conduits and its communicating cylinders, the walls of the packing cups being sealed against the cylinder walls by fluid pressure supplied to the first mentioned cylinders, whereby the fluid pressure projects the closure elements along the cylinders and into the bore of the housing for abutting cooperation defining a closure means for said bore, the bottoms of the cups and the abutment plates being recessed so that when the closure elements are in abutting relation the recesses define a restricted bore opening through the closure means longitudinally of the bore of the housing, means cooperating with the abutment plates for arresting projection thereof when the closure elements are in abutting relation with the restricted bore coaxial with the bore of the housing, the bottoms 70 of the packing, cups being expansibly distorted by the fluid pressure for projection into therestricted bore for sealing around a men,1b, .ex--- tending therethrough, and an operating connection between the spider for each packing cup and the piston in the corresponding auxiliary cylinder, whereby fluid pressure supplied to the auxiliary cylinders moves the pistons therein and retracts the closure elements along their cylinders so as to clear the bore of the housing.

6. In a blowout preventer, a housing having a bore, radial cylinders opening into the bore, closure elements in the cylinders each including a cup packing having the bottom of the cup toward the axis of the bore, and means for supplying fluid pressure to the cylinders, the walls of the packing cups being sealed against the cylinder walls by the fiuid pressure, whereby said pressure projects the closure elements along the cylinders and into the bore of the housing for abutting cooperation defining a closure means for said bore, the bottoms of the packings being recessed so that when the closure elements are in abutting relation the recesses define a restricted bore opening through the closure means longitudinally of the bore of the housing, and the bottoms of the packing cups being expansibly distorted by the fluid pressure for projection into the restricted bore for sealing around a member extending therethrough.

7. In a blowout preventer, a housing having a bore, radial cylinders opening into the bore, closure elements in the cylinders including a cup packing having the bottom of the cup toward the axis of the bore, a spider in each cup, connections between each spider and the wall of the cup fixing the spider against longitudinal displacement relative to its cup but permitting radial displacement of the wall of the cup with relation to the spider, means for supplying fluid pressure to the cylinders, the walls of the packing cups being sealed against the cylinder walls by the fluid pressure, whereby said pressure proiects the closure elements along the cylinders and into the bore of the housing for abutting cooperation defining a closure means for said bore, the bottoms oi the packings being recessed so that when the closure elements are in abutting relation the recesses define a restricted bore opening through the closure means longitudinally of the bore of the housing, and operating connections for the spiders whereby when the fluid pressure in the cylinders is relieved the closure elements are retracted in their cylinders so as to clear the bore of the housing. a

8. In a packing device, a plurality of closure elements relatively radially contractible for cooperation defining a closure means surrounding a bore opening therethrough axially of said radial contraction, the portions of the closure elements which define the wall of the bore being formed of packing material and adapted for expansive distortion into said bore, the closure elements shutting of! the bore from the space in rear oi said packing material, and means for exerting fluid pressure in said space for expansibly distorting the packing material for projection into the bore for sealing around a member extending therethrough.

9. In a packing device, at least three of closure elements relatively radially contractible for cooperation defining a closure means surrounding a bore opening therethrough axially of said radial contraction, the portions of the closure elements which define the wall of the bore being formed oi packing material and adapted for expansive distortion in said bore, and means for exerting fluid pressure against said portions of the closure elements, other than directly irom the bore, ior expansibly distorting the packing material for projection into the bore for sealing around a member extending therethrough.

10. In a packing device, a plurality of closure elements relatively radially contractible for abutting cooperation defining a closure means surrounding a bore opening therethrough axially of said radial contraction, the portions of the closure elements which define the wall of the bore being formed of packing material and adapted for expansive distortion into said bore, the closure elements shutting off the bore from the space in rear of said packing material and means for exerting fluid pressure in said space for expansibly distorting the packing material for projection into the bore subsequent to abutment of the closure elements for sealing around a member extending through the bore.

11. In a packing device, a plurality of closure elements comprising packing and cooperating abutment plates, the closure elements being relatively radially contractible for cooperation defining a closure means surrounding a bore opening therethrough axially of said radial contraction, the portions of the closure elements which define the wall of the bore being formed of packing material and adapted for expansible distortion into said bore, the closure elements shutting off the bore from the space in rear of the packing, and means for exerting fiuid pressure in said space for expansibly distorting the packing for projection into the bore for sealing around a member extending therethrough, with the abutment plates preventing excessive distortion of the packing longitudinally of the bore.

12. In a blowout preventer, a housing having a bore, radial cylinders opening into the bore, closure elements in the cylinders each comprising packing and an abutment plate fixed against longitudinal displacement relative to the packing and positioned relative to the packing longitudinally or the bore of the housing, the portions of the closure elements which define the wall of the bore being formed of packing material and adapted for expansible distortion into said bore, and means for exerting fluid pressure in the cylinders for projecting the closure elements along the cylinders and into the bore oi. the housing for abutting cooperation defining a closure means for said bore, the packings and the abutment plates being recessed so that when the closure elements are in abutting relation the recesses define a restricted bore opening through the closure means longitudinally of the bore of the housing, and the packings being adapted for distortion by said fluid pressure and relative to the abutment plates which are fixed thereto, for projection into said restricted bore for sealing around a member extending therethrough.

13. In a blowout preventer, a housing having a bore, radial cylinders opening into the bore, closure elements in the cylinders each including a cup packing having the bottom of the cup packing toward the axis of the bore, said bottoms of the cup packing being formed of packing material and adapted for expansive distortion into said bore for sealing around a member extending therethrough, and means for supplying fiuid pressure to the cylinders for projecting the 010- sure elements along the cylinders and into the bore of the housing for abutting cooperation and for expansively distorting the bottoms of said cup packings for sealing around a member ex tending therethrough.

J OHN W. MACCLATCHIE.

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