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Publication numberUS1662311 A
Publication typeGrant
Publication dateMar 13, 1928
Filing dateApr 4, 1923
Priority dateApr 4, 1923
Publication numberUS 1662311 A, US 1662311A, US-A-1662311, US1662311 A, US1662311A
InventorsLeland S Hamer
Original AssigneeLeland S Hamer
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Well-capping device
US 1662311 A
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Description  (OCR text may contain errors)

March 13, 19278.

' L. S. HAMER WELL CAPPING DEVIQE Filed April 4, 1923 vlo Patented `Mar.13 i a .i

LELAND s. or Formularen, ammonium.

WELL-carpino nevica. Y

application 111er April 4, i923. semi ivo. aaasia This invention relates to. a well capping device, and it is an object of the inventionto provide an effective, improved device of thisl sirable to remove the cap fromthe casingas this not only interferes with circulation but also allows air to get into the casing and interfere with the ceinenting"operation. The usual cementing processes require the insertion of one or more devices into the cas` ing, during the cementing operation, thus ordinarily making it necessary to remove the cap at a time or times when its removal 1s detrimental.

g It is an object of this invention to provide an improved construction for quick detachable well caps of the general character towhich the above mentioned copending appli- `the like, and means adapted to be operated -40 cation is'broadly directed. y t Y Another object of this invention is to provide a Ydevice to be used in combination with a Well casing during the carrying out of a cementing process, or. the like, which .permits ofdevices or objects being .inserted into the well casing at any time during the carrying out of the process Without removal of the device from the casing.

It is another object of my invention prolvide packing means in connection with a well cap for making it 4tight on a casing, or

by an elevator, or `the like for actuating the packing.

1 present invention will be best and more fully they, together, form a 'ringlike structure ivunderstood from the 'following detailed description of atypical preferred form and-tap The various objects and features of: my

plication thereo throughout which description reference is'had to the ,accompanying drawings, in which:

. Fig.' 1 is a fragmentary sectionalV view .showing my improved cap in place Ona-'well casing, and 1n condition ready for' carrying 1 out a cement-ing process, or the like;

indicated by line 2--2 on Fig.v 1

Fig. 2 `s an 'enlarged plan section, taken as Fig.' 3 is an enlarged plan section, taken as indicated by line 3-3 `on Fig. 1;

Il fis anenlarged plan` section, taken as indicated by line .4--4 on Fig. 1;

of a portion of' Fig. 1;' and 4 Fig. 6.is a se'ctlonalY vievvl takenas indicated by line'6-6 on Fig. 5.

Fig. 5 is an enlarged detail sectional view Throughout the drawings, numeral designatesfgenerally, a typical well casing,and numeral 11 designatesa coupling mounted on the upper endof the casing 10.

The device provided bym invention includes, generally, a cap `12, apted to be ar-. ranged over the coupling 11; means 13, for releasably securing. the cap in position in connection `with the coupling 11; means `14, for packing the cap with the coupling 11; operating means 15, for the packln 14; a

magazine 16, v4iii connection with t e ca adapted to -hold objects so'that the can e kdeliveredto the casing while the device is in position in connection with the casing and couplinggfand means 17, for dischar ing objects from the magazinestructure into the casing. a y

The cap 12 may be a cast member having a main or bcdyrpart 18 and an annular flange t part. 19 which-projects fromm the main part v 18,4 and is adapted lto receive the coupling 11. The means provided by the present invention for releasably securing the cap in connection `withY the coupling, includes general1y',a yoke Y20, adapted to more or less .closely oreceive the casing 10; a gate 21, adapted tov close the yoke to retain the casing 10 in it; and arms4 22, which connect the 4structure formed by the yoke'and gate with the cap. The gate21 is with one side 'of the yoke 20 by means of a suitable pivot pin 22", and is releasably 'conneciged with the other side of the yoke 2O by a spring catch mechanism 23. The oke and gate are designed and proportione so, that .which more or lessclosely embraces the casing 10 when the gate closed. When a hold the gate 21 closed the mechanism ma .include a T latch 24 p ivotally connected wit one of the parts,"sayforiinstancethe ate 21, by a pivot pin 25, and lugs 26 provided on the other part to cooperate with the head pivotally connected v spring latch'nieehanisin'23 is employed to 24a of thelatch; The head- 24a of the latch is 'screvv threaded ontlie body 0f the latch vSo that it canY be set against the lugs 26 to set the mechanism' against't'ieing released. It is ldesirable to providel a27, or

in connection with the latch 24toinormally yieldingly hold it inposition to'cooperatc with the lugs 26, and to design and proportion the various .parts of the mechanism so that it automatically operates to connect the gate and'yoke upon the gate being closed.v

' In accordance with the preferred form of my invention, there `are. two arms 22 arranged substantially diametrieally opposite each other with relation to the axis of the device, and rigidly connect with the sides of the yoke 2(). In practice the arms and the yoke can be advantageously cast or otherwiseformed' integrally, as I have illustrated in the drawings. The arms 22 extend upwardly from the sides of the yoke to the main part 18 of the cap, and are pivotally connected with the main part of the cap by suitable 'pi vot pins 31. I prefer to provide lugs 32 on the inner sides ot .the arms at their upper ends concentric with the axis of the pivot pins 31 so that they seat in suitable sockets 33 formed in the cap and operate' to relieve the pivot pin'31 of strain when the device is in operation. The arms'22 being connected with the capand related to the yoke in the manner just described, and asl have clearly illustrated throughout the drawings, connect the yoke -with the cap so thatit can be conveniently swung out to clear the casing and coupling when the device. is being arranged on or removed from position in connection with the casing and coupling.` Further, the gate 21 being pivotallyconnected with one side of the yoke, it is neeessaryto swing or manipulate only 'one part to clear the casin when the gate I. trated inthe drawings l as typical of that which may be employed incarrying out my invention, includes a body of packing28, arranged in a recess 29 which extends `upwardly in the lan'ge part 19 of the cap, and

a ring 30 slidablyr carried in the recess 29 back Vof the body of packing, as I have clearly illustrated in Figs. 1 and 5. When thel ring 30 is orced'or otherwise moved upwardly in the- 'recessit expands the packing' 28 between the flange portion of the cap andthe coupling-1150 thatv the cap and coupling are tightly packed together.'

The packing actuating means 15, inac- A-cordance with my present invention, in'- cludes plungers 34, carried by the'casing en-v circling strueture formed by thev yoke and ate sothat their lower end portions 36 pro-v ]ect below the structure formed by theyoke ling and gate and are movable to a position where they do not project .from said stru cturc. The plungers `are slidably carried 1n suitable'openings 35 formed in. said structure and, in the present case, 1n openings iorlned in the yoke 2O preferably at or close to the points where the arms 22 connect with the side parts of' the yoke. The lower end portions 3G of the pluugers in projecting below the casing encircling' structure are 1n position to be engaged by an elevator, or like device, that may be applied to the casing below the device7 so'that they are moved upwardly upon the elevator belng brought up into engagement with the ring structure. 'lhe .movement of the 'plungers is communicated tothe ring 30 of thc packing means by screw members 37 carried by the ring 30 so that th-eyproject downwardly and are -in line with the plungers when the device is in position on the casing and coupling.' The screw parts may, of course,A

be adjusted to project various distances from the ring and thereby provide an ad justment in the packing and packing actuatr lneans. Openings 38 'are formed throughthe plungers 34,at the upper side of the ring structure, and wedges 39 are provided so that they can be arranged' 1u the openings 38 to lock or secure the packingin .an actuated position. Itwill be obvious,

of course,- that the packing may be actuated or tightened at any time without the employment of an elevator, as I have above described, by'driving or otherwise forcing the wedges through the openings 38. Then the wedges 39 are in position holding the packing they can be very easily and quickly re- -leased by driving them out of the openings 38. l l .The magazine 16 includes a pluralityvot .sections or parts arranged in connection with the capV 12, preferably in connectionwith the main part 18 of the cap 12 and so that they are concentric with-the casing and collar. The lower section/l0 of the magalllll zine 16 is carried by the main part 18 of the Y cap so that. its lower end. portion 41 extends intothe upper en d of the coupling 11 when the device is in place on a casing and coupling. The lower section. 40 of the magazine may be formed of a piece'of casing, or the like, and, in the prcsentscase., is ,formed of a piece of casing of the -same diameter as the casing 10. However, the exterior of the lower end portion 41.01? the section 4() is turned down so that the section fits freely into the coupling 11 in the manner illustrated in Figs. land 5. The lower end por-- tion 41 ot the section 40 in extending into vthe eouplmg covers the upper end of the coupling so that `objects are delivered from the. magazine into the easing 10 without danger of being caught by the coupling. In the form of construction illustrated -in 45 form of-'constructi'o'n the V.section 50 is the uppermostsection and is, therefore, closed'.

by a suitable'cap 53.` The cap is'provided the drawings,'the section 40 screw threads into the main part of the vcap andextends some little distance above the main part of thecap g 5 The magazine 16;'wl'1icli I lhave chosen to illustrate inthe drawings, as a typical magazine'structure, such as may be employed 1n Asection 40 by means yof a. screw 45 screw.

threaded inthe main part 18 ot'lthecap to extend through the section 40 so that 'it 'pro-- is turned until its inner end is .withdrawn from 'within the section 40. T he magazine 16 is provided with a middle section 46'to carry the timber 44. The section 46 isa 'conlparativelylong section of casing, or the like, in that the'tlmber is' usually 4comparatively long. The section' 46 is connected with theJ upper end-of the section 40 by a suitable coupling 47. As a means for-holding-orjretaining the ti mberi 44 inthe. section 46-I ara range a screw 48 in the 'coupling 46 so that it can be extended into the magazin@ structure under the timber;l 'The screw 48,'like the screw 45, may b e retracted 'torelease the 'timberil Y. The upper swab 4 2 "is 'carried in a section 50 mounted on the upper end lof the *section 46 by a suitable coupling 51,- 4The Section 50, like theother5 sections of the magazine, may be formed of-a section of casing and `may be off a diameter or'size .to properly carrythe swab 42.' A screw 52 is' carried by the'coupling`51 so that it'` extends into t e magazine' in a manner to? hold -o'r retain the swab 42 in the section 50. "In the present' 'with an'l ey'e4 54 to receiiual a suitable 'bail 55,

lao' Vandlh'as a"downwa rd1y facing 'shoulder 56l which can be engaged b an elevator, orthe 'i "like, arranged around t e section 50 if 'it is'- for the magazine 16, it may be made' or built -up toaccol'nmodate any number or' arrange? lment ,ofobjects that-may require insertion int-o the casing` 10. For '1nstance, the magazine may be extended by addingsect'ions to it and may be reduped by taking sections- ,into thc device through openings 59 and -60 jects into the section under the swab. lVhen 1t is desned to release `the swab the screw? in'to' the casing 10. It .willbe obvious how- 'the' valves '6 8 and 69 'likewise provide con.-

Y the magazine, as 'desire With the general arrangement and form 'of construction which I have just described' cap` 53 applied directly to the upper end of the section 40. `In practice, however, it is desirable to construct the device `for one particular class of workand to make the magazine structure more or less permanent. 7U.

`In the' particular form' of theinvention, illustrated in the drawings, there are two pipe lines 57 and 58 which are connected provided in the main'part o f the cap. The supply lines 57 and 58 are provided' with wntrol valves 61 and-62, respectively.

The means 17, which 'I have herein. Set forth for ejecting or discharging objects -from the magazine 16, isa fluid pressure means, andincludes Val pipe connection be s tween' the supply pipe 57 andthe uppervpart ot each 'of the sections of the'maga'zine. In accordance with the preferred arrangement the fluid pressure means includes a main pipe 86 66v which has connection with the supply pipe v '57,' and-pipes-64, 65: and 66 which connect the pipe 63 with .the 'sections 40, 46 and 50, respectively. Means are provided for controlling 4the4 flow from the supply pipe 457' 90 Vto the sections of the magazine, and, 1n the present case, includes valves' 67, 68 and 69, arranged' in the pipes 64,65 and 66, res ec-4 tiyely. as I have clearly illustrated in ig. 1.l lVhen thevalve 67 is open -fiuid pressure is, transmitted from the supplyv pipe 57 through the pipes 63 and 64 into the upper vpart of'the section 40so that it -will force the swab Ll-do'wnwardly in the section and trol means wherebyiluid pressure from the 1' pipe 5@ may be admitted into the sections 46 .A and 50- above the timber and 4swab so that:

the timber and swab ma' bedischarged vfrom d. It is to be under' stood, of course, thatv .when the control valves are open to discharge the objects from the magazine that t-he retaining screws are manipulated to 'release l' the objects.

I'n applying thedevice to a casing and 'coupling the cap 12is yarranged on' theconpling so thatits'lange part 1 9 extends overl the coupling, `while the lower p ortlon 41 of the magazine section 4 0 extends into the couand coupling Huid can be admitted into the f casing as desired from-thesupply pipes 57 i Y. and 458 through the control valves 61 and 62. 13o

-npling." The yokeL20 isthen swung into osltion where it embraces the casing an the gate 21 is' closed. The pack1ng actuat1ng `wedges 39 in the openings 38. lVhen thev devicefhast-husbeen mounted on the casmg Further, thelswabs and timber carried by the magazine can be ejected from the inaga zinel into the casing: .'vlien desired by suitable manipulation of the controlya'lves 67, 68 and 69, and can, of course, be thus ejected from the magazine into Vt-'lie,"c:isiiig. 10 without' 'removing' the device and without inany i ;way interferingr with circulation in vthe easing. Toreniove the device it is merely .necessary to release. thel latch lsol that. the gate i'villopen'and tliensiving the yoke an'ay from the casing so that it will clear the couplingwlien the device is removed. The device Amay be handled in any suit-able manner,

for instance. by means of an elevator arranged under the ring structure formedl by the yoke and gate-or under the' cap 53.

Having described only a typical preferred forin of my invention l do not-irish to limit myself to the specific details hereinabove set forth'. but wish to 4reserve to myself. any

changes orvariations that may appear to those skilled in' the art or fall within the scope-of ythe following claims; yfurther, I Awish to lhave 4the various phases of my invention considered broadly and without specific reference to unrelated details that I may .have set .forth and without'specific reference together phases which are indeendent, for-example, various phases of my .invention relating to the magazine areto be considered generally with relation to the strueture'which engages under the coupling and are notv to be considered limited in any sense to any 'specific forni or ty `e of such structure that I may have set fort and may i have Vclaimed e specifically as another feature pling-` y said structure.-

i nation-'mth' a casing having a coupling ony of vmy invention.

' Having describeda preferred form of my' invention, I claim:

1. A device adapted to be used in combiA nation with a casing having a coupling onl `its vend embodying, a cap adapted. to be arranged in connection with the coupling, afstructrure'adapted. to be arranged around the casing under the coupling `and including Y a yoke and a gate for closing the yoke, and a pair of hinged arms connecting the yoke with the cap so that th^e cap is held `in connection with the coupling by said-structure.

2. A device adapted to be used in'combination with a caslng having a coupling on its en d embodying," a cap adapted' to be arranged in connection with the coupling, a

. vstructure adapted to be arrangedaround the casing under the con ling and includin a yoke 4and a gatev for e osingthe yoke, an a pair of arms rigidly connected with theyoke and'movably connected With the cap so that the ea is held in connection withthe .cou-

l 3. A device adapted to be used in combiits end embodying, Aa. cap adapted to be casing under the coup ing.

arranged in connection withlthe coupling, a

structure adapted to he arranged around the easing'under the coupling and including a yoke and a gate fory closing the yoke, and a p air of arms rigidly connected with the yoke and pivotally connected with the cap so that the cap Ais held in connection with the coupling by said structure.

4. A device adapted to,be used in combi'-4 nalion with a casing' haring a coupling on its end embodying. al cap' 'adapted lo be .arranged in connection with the coupling, a. struct-ure adapted to be arranged around the easing under the. coupling and including a yoke. and a gatefor closing tlie'yokc, and a.v pair ot' arms lrigidly connected with the yoke. and pivotally connected with the cap about an axis substantially diamctrical ot' the. device so that tlie cap is held 1n connection with the coupling by said structure.

5.' A device adapted 'to be used vin combination with a .casing having a coupling on its end embodying, a cap adapted to be'.

arranged in connection with the coupling, a structure adapted tolbeyirran'ged around the a pair of arms arrangedat opposite sides of the device and being' connected with` said structure and being pivotally connected with the cap about an axis substantially diainetrical of the dev ice.j

6. A device adapted-to be used in combination with a casinghaving a coupling on its end embodyin, r, a cap' adapted to bel arranged in connection with the coupling, a structure to be arranged around the casing under the coupling and including` a yoke,

' agate pivotally connected with one side of the yoke, and' a spring latch device lfor -connecting the gate with the other side ofthe yoke so that it closes theyoke, a pair of arms connected with the yoke and pivotally connected with the cap so that the cap is lield in around vthecasing iinder.- the coupling and having connection with the-cap. so that it holds 1t on ;thfe coupling',.and Ameans for actuating'the .packing including' a part projecting from the said structure."

8. A device adapfed'to be usedfin coinbiv nation with` acasinghavin a coupling on its end embodying, a vcap a apted tobe ar-v ranged in connectionl with the coupling,A

means for packingjthe cap and coupling together, -a structure adapted lto be arranged around the casing 4 under the couplin and having iconnection with thel cap.v so tat itl'L holds it on'th'e couplingjand meansv for actuating the packing including a part'project-- v ing downwardly .from the said structure.

ranged in connection .with the coupling, means for packing the cap and coupling togethJer, a structure adapted to be arrangedaround the casing -under the coupling land havin connection with the cap so that it holds it on the coupling, and means for actuating theV packing including aplunger carried by said 'structurev so that it willactuate the ackingupon being moved upwardly and has a part projecting downwardly from said structure. n

- f 10. A device adapted to be used in combination with a casing having a coupling on its end embodying, a cap adapted to bc arranged in connection with the coupling,

Ameans for packing the, cap and coupling together, a structure adapted to be arranged aroundjthecasing under the :coupling and having connection with .the cap so that it holdsit 'on the coupling, Aand fmeans for acjtuating the packing. vincludingfarpart proecting from said structure to be engaged yan elevator orthe -like brought Vinto'engagement with the structure, and means for setting the packing inV an Yactuated position.

11. A'device adapted to be used in com- 'bination with a casing having a coupling on its end embodying; a cap adapted to be arranged in connection vwith the, coupling, means v for packing.. the cap and coupling together, a structure adaptedto be arranged around the casing under the' coupling and' havin connection with the'cap so that it holds it onthe coupling, and means forvac tuatingthe packing includiii afpart projecting romfsaidzstructure engaged by anelevator 'or-the like brought into engagement with the structurez and` means in connection Swith thev packing, andV actuating means for adjusting theamount the packin'gis actuated'upon actuation of the actu- ."atmg A -12. A device adapted to beused in connec# means;

tion with'the. casing having. coupling on its end embodying2 a cap -a r in connection structure ada ted to be assembled around the casing im er the coupling and connected apted to bejarf. with the coupling, a

with the cap to holdit on-the coupling, and a magazine carried by the cap so that it ex tends freely into the coupling, the' magazine beingadapted to carry an object. so that it can be released therefrom into Vthe casing.

13. A device adaptedto be used in combination with a casing having a coupling. on `its end embodying, a cap having a main part and a flan e part adapted to be arranged over the upper e d of the coupling, and there being a recess in the lower portion of the flange part, packing carried in the recess, a 'structure adapted to embrace the casing below the coupling including a yoke, a gate pivotally connected to one side of the yoke, and a spring latch for releasably connecting the gate with the other side of the yoke to close the yoke,

sis"

fio.

operating means for the packing including a plunger carried byA said structure so that it `has a part projecting downwardlytherefrom to be engaged by an elevator or the like, wedge 'means for actuating and holding the plunger, a pair of arms rigidly connected with the side parts ofthe yoke and pivotally connectedA with the cap about an axis substantially diametrical of the cap, -a magazine in connection with the capincluding a lower section carriedA concentrically by the 'main portion of the cap so that ,it extends freely intol the coupling, and a plurality of other sections arranged end to e'nd above the lower section, a cap closing the upper end of the uppermost section lof the magazine, means in connection witheach of the sec` vtions of the .magazine for releasably holding an object in it, a supply pipe vconnected into the cap, and pipe connections between the supply pipe and the sections of the magazine whereby pressure can be delivered to the sections to discharge objects from them into the casing. 1 'e 14. A device to be used in combination with a casing having a coupling on its end and an elevator associated with the casing, a cap adapted to close the coupling, packing carried by said cap, and means operatively connectin said elevator and said packing whereby-t e raising of said elevator is adaptved to make a tight connection between said cap and said coupling.

.In 'tness that -I claimv theforegomg I have hereunto subscribed my name this 30th,

day of March v1923. A v LELAND S. R.

Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US2615519 *Jun 30, 1947Oct 28, 1952Carr Charles JPlug handling head for well casings
US2620037 *Jul 2, 1951Dec 2, 1952Halliburton Oil Well CementingCementing head
US2630179 *Jun 24, 1949Mar 3, 1953Brown Cicero CMethod of and apparatus for cementing wells
US2647582 *Feb 9, 1949Aug 4, 1953BrownApparatus for cementing wells
US2662602 *Jun 27, 1947Dec 15, 1953L L RectorMeans for guiding, floating, and cementing well casing in bored holes
US2664163 *Apr 16, 1949Dec 29, 1953L L RectorWell cementing apparatus
US2854079 *Jul 27, 1953Sep 30, 1958L L RectorWell cementing apparatus
US2992839 *Jul 14, 1954Jul 18, 1961Tubi Bonna S P AAdjustable and replaceable conduit coupling
US3181901 *May 3, 1962May 4, 1965Watts John DInstant release connection with a reduced effective angle of friction
US4253638 *Aug 2, 1979Mar 3, 1981Cameron Iron Works, Inc.Blowout preventer
US4522430 *Aug 26, 1981Jun 11, 1985Halliburton CompanyQuick connect coupler
US4524998 *May 4, 1982Jun 25, 1985Halliburton CompanyTubular connecting device
US4566168 *Jan 9, 1985Jan 28, 1986Halliburton CompanyQuick connect adapter
US4613161 *Mar 8, 1985Sep 23, 1986Halliburton CompanyCoupling device
US4674573 *Sep 9, 1985Jun 23, 1987Bode Robert EMethod and apparatus for placing cement plugs in wells
US4828025 *May 17, 1988May 9, 1989Mrw PartnershipBlowout control means
US4917184 *Feb 14, 1989Apr 17, 1990Halliburton CompanyCement head and plug
US5152554 *Dec 18, 1990Oct 6, 1992Lafleur Petroleum Services, Inc.For connecting to a cylindrical member
US5205356 *Oct 7, 1991Apr 27, 1993Abb Vetco Gray Inc.Well starter head
US5282653 *Dec 18, 1991Feb 1, 1994Lafleur Petroleum Services, Inc.Coupling apparatus
US5348351 *Jan 31, 1994Sep 20, 1994Lafleur Petroleum Services, Inc.Coupling apparatus
US5971079 *Sep 5, 1997Oct 26, 1999Mullins; Albert AugustusCasing filling and circulating apparatus
US6173777Feb 9, 1999Jan 16, 2001Albert Augustus MullinsSingle valve for a casing filling and circulating apparatus
US6390190Sep 25, 1998May 21, 2002Offshore Energy Services, Inc.Tubular filling system
US6415862Aug 14, 2000Jul 9, 2002Albert Augustus MullinsTubular filling system
US6517125 *Aug 14, 2001Feb 11, 2003Halliburton Energy Services, Inc.Cementing head
US6604578Jan 18, 2002Aug 12, 2003Albert Augustus MullinsTubular filling system
US6675889Aug 8, 2000Jan 13, 2004Offshore Energy Services, Inc.Tubular filling system
US6715542Jun 12, 2003Apr 6, 2004Albert Augustus MullinsTubular filling system
US6722425Nov 9, 2001Apr 20, 2004Offshore Energy Services, Inc.Tubular filling system
US6779599Jan 18, 2002Aug 24, 2004Offshore Energy Services, Inc.Tubular filling system
US8381808 *Oct 29, 2008Feb 26, 2013Halliburton Energy Services, Inc.Cement head
US8695715 *Jan 21, 2013Apr 15, 2014Halliburton Energy Services, Inc.Cement head
Classifications
U.S. Classification166/70, 285/302, 417/904, 285/417, 166/92.1, 285/420, 285/421
International ClassificationE21B33/03
Cooperative ClassificationE21B33/03, Y10S417/904
European ClassificationE21B33/03