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Publication numberUS3331385 A
Publication typeGrant
Publication dateJul 18, 1967
Filing dateSep 24, 1964
Priority dateSep 24, 1964
Publication numberUS 3331385 A, US 3331385A, US-A-3331385, US3331385 A, US3331385A
InventorsTaylor William T
Original AssigneeModern Drilling Tools Inc
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Closure apparatus with removable plug
US 3331385 A
Abstract  available in
Images(3)
Previous page
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Claims  available in
Description  (OCR text may contain errors)

y 9 w. T. TAYLOR 3,333,335

CLOSURE APPARATUS WITH REMOVABLE PLUG Filed Sept. 2%, 196;; 3 Sheets-Sheet l W/ ///0'm 7. Ey/ar INVENTOR.

Bar 4&4, V PM I July 18, 1967 v w. T. TAYLOR 3,331,385

CLOSURE APPARATUS WITH REMOVABLE PLUG Filed Sept. 24, 1964 3 Sheets-Sheet 2 W////0r/7 7. Toy/0r INVENTOR.

July 18, 1967 w. T. TAYLOR 3,331,385

CLOSURE APPARATUS WITH REMOVABLE PLUG Filed Sept. 24; 1964 3 sheets-sheet 5 as '5: ifs? 10 I 10 2 wiz I; H "L 5; A if 5 ":2 g f aw l7? 7 4-- 13/] a k ii if 33 -90 2 *7 900 W/mam r. ray/0 I NVEN TOR.

ATTOR/VfVJ United States Patent 3 331 385 CLOSURE APPARATUE WITH REMOVABLE PLUG Wiiiiam T. Taylor, Houston, Tex., assignor to Modern Drilling Tools, Inc., Houston, Tex., a corporation of Texas Filed Sept. 24, 1964, Ser. No. 398,898 2 Claims. (Cl. 137-327) ABSTRACT OF THE DISCLOSURE The present invention relates to a new and improved closure apparatus for tubular members.

In drilling oil or gas wells or the like by the rotary drilling method, the drill bit is rotated by a string of drill pipe connected to a kelly suspended in a derrick at the earths surface. Drilling mud or chemically laden drilling fluid is pumped through the kelly and string of drill pipe to the drilling bit in a manner well known in the art. Heretofore, during the drilling operations, Whenever the drilling pipe was disconnected from the lower end of the kelly, the entire contents of drilling fluid in the kelly would immediately empty out onto the derrick floor. In drilling a well, it was not unusual for 100 to 150 barrels of drilling fluid to thus be lost, causing not only the waste of large quantities of expensive drilling fluid but also spraying mud all over the adjacent area and workmen and making the derrick floor dangerously wet and slippery and consequently hazardous for persons working on the derrick floor.

It is therefore an object of the present invention to pro vide a new and improved closure apparatus to retain drilling fluid in a kelly when it is disconnected from a string of drill pipe.

It is also an object of the present invention to provide a new and improved closure apparatus for use with a kelly which will open to allow fluid to be pumped therethrough under pressure in one direction and which will close when the back pressure on such fluid exceeds the pump pressure.

And yet another object of the present invention is to provide a new and improved closure apparatus for use with tubular members which will open to allow fluid to be pumped therethrough under pressure and which will automatically close when the pressure drops.

A further object of the present invention is to provide a new and improved closure apparatus for use in a tubular member which will open to allow fluid to flow there through in only one direction and which will automatically close to the flow of fluid therethrough in the opposite direction.

And still another object of the present invention is to provide a new and improved apparatus for connecting drill pipe to the lower end of a kelly including means for retaining a standing column of drilling fluid in the k lly.

And still another object of the present invention is to provide a new and improved device for use with tubular members to open upon the application of a predetermined fluid pressure to fluid flow therethrough in one direction and to automatically close to prevent fluid flow therethrough from the opposite direction.

Another object of the present invention is to provide a new and improved closure apparatus that can easily "ice and readily be positioned on a kelly by an ordinary drilling laborer without special tools, skills, or equipment.

And yet another object of the present invention is to provide a new and improved closure apparatus for positioning on a kelly which will open to substantially the full diameter of the bore of the drill pipe connected to the kelly.

An object of this invention is to provide a new and improved closure apparatus for connection to a kelly and drill string having means therewith for permitting wire lines to be run in the drill string.

One object of this invention is to provide a new and improved closure apparatus which prevents well blowout through the kelly.

Yet another object of this invention is to provide a new and improved closure apparatus which closes to prevent reverse flow and yet pressurizes the kelly to enable the operator to ascertain the pressure in the well string.

Another object of this invention is to provide a new and improved closure apparatus having means removable by a retriever to permit a wire-line to be run into the drill string.

Other objects and advantages of the present invention will become readily apparent from a consideration of the following description and drawings wherein:

FIG. 1 is an elevational view showing one use of the present invention wherein it is connected to a kelly and a string of drill pipe as they are positioned for rotary drilling;

FIG. 2 is a sectional view, partly in elevation, illustrating one preferred form of the invention connected to a kelly and drill string with a retriever extended through the kelly to the invention;

FIG. 3 is an enlarged view similar to FIG. 2 showing in greater detail the structure of the closure apparatus of this invention closed to the flow of drilling fluid;

FIG. 4 is a view similar to FIG. 3 showing the closure apparatus opened to the flow of drilling fluid through the kelly and into the drill string;

FIG. 5 is a sectional view of another preferred embodiment of this invention in the closed position;

FIG. 6 is a sectional view similar to FIG. '5 showing drilling fluid bleed means for pressurizing the kelly to enable the operator to read pressure in the drill string; and

FIG. 7 is a sectional view taken on line 10-10 of FIG. 5 showing passages for bleeding drilling fluid through closure apparatus.

An embodiment A1 of this invention is illustrated in FIGS. 2-4 where the closure apparatus A1 is shown connected to the kelly K and the drill string P is suspended therebelow. The closure apparatus A-l is formed of an upper tubular housing 60 and a lower tubular hOusing 61 which housings are joined by means of threads indicated at 62 in defining a tubular member having passage means indicated generally at 64. The protective wear sleeve R is placed about the closure apparatus A-l to provide protection from wear and rough handling with tongs or the like. The upper hollow member 60 includes a set of threads 60a which is adapted to coact with the kelly K and threads 61a are carried on the member 61 for connection to the drill string P.

The upper tubular member 60 includes an annular shoulder 60b and an adjacent set of threads 60c which are engaged with an annular sleeve 66. The sleeve 66 is tapered inwardly of the passage 64 at 66a to define a shoulder 66b which abuts the lower end 60d of the upper member 60. The lower end 60d of the upper tubular member includes an annular groove 60e which is V-shaped for receiving a trapezoidal seal member 68 having an inwardlly facing shoulder extending into the passage 64 and which is formed of a resilient material to provide sealing contact with other components of the closure apparatus A-1 of this invention.

'A valve body indicated generally at 72 is positioned in the passage means 64 and serves as means for closing the passage 64 to the flow of pressure fluid in cooperation with coacting means in the form of the seal member 68. The valve body indicated generally at 72 includes a narrow neck 72a with an axial passage 72b extending through the neck 72a to a threaded portion 72c opening to the passage 64 communicating the kelly K with the closure apparatus A-l of this invention. The valve body 72 flares outwardly at 72d and extends inwardly at 72a to define a conforming surface adapted to cooperate with the valve .seat member 68 clamped between the sleeve 66 and the upper tubular member 60.

A removable member 75 in the form of a plug 76 has a bolt 77 axially mounted therein with the head of the bolt extending above the plug 76. The removable member 75 includes a set of threads 76a for engaging the threads 72c in the valve body '72 for connecting the plug in the valve body'and limiting fluid communication there- 'through. The bolt 77 connected to the plug 76 is preferably a left-handed threaded bolt for reasons to be explained.

The axial opening 721) of the valve body indicated gen erally at 72 is enlarged at 72 immediately adjacent a plurality of fluid ports or openings 72g. Each of the ports 72g extends from the enlarged axial opening 72] through the valve body 72 in communication with the passage means indicated generally at 64. The lateral openings 72g are defined by a group of metallic ribs 7211 which are connected to a support member 72i which defines the enlarged opening 721. The support member 721 is aligned with the passage means 64 and thereby guides the valve body 72 with respect to the valve seat member 68 for sealing engagement.

A support member 721' includes a pair of annular ring grooves 72 adapted to receive seal means such as the rings 72k shown positioned in the grooves. The enlarged axial opening 72 extends downwardly through the valve body 72 and is defined by a skirt 72! which terminates at an annular perpendicular shoulder 72m. The annular shoulder 72m provides a seat for resilient means such as the compressible coil spring 80 shown in the drawings. The spring 80 extends axially of the lower tubular housing 61 and is contacted against a support ring 81 resting on an annular shoulder 61b interiorly of the lower tubular member 61. It may be appreciated that the resilient means 80 is restrained to provide'a force axial of the closure apparatus A-1 of this invention for urging the valve body 72 against the valve seat for operation as will be described hereinafter.

The valve 72 is adapted to be moved within the chamber defined by the annular sleeve 66 and it may be appreciated that the valve 72 bears against the sleeve 66. For Wear purposes, the sleeve 66 may be made of a durable ceramic material for receiving the movable valve 72. A rubber O-ring 82 is positioned adjacent the lower end of the sleeve 66 to prevent leakage of drilling fluids into the annular space between the sleeve 66 and the lower tubular member 61.

Attention is directed to FIG. 2 wherein the removable member 75 is grasped :by a retriever indicated generally at 84. A tubular member 85 of a size appropriate to fit within the kelly K is threadedly engaged with a plug 84a and the plug 84a is connected to a bushing 8417 on which axially extending fingers 84c are carried. A support bar 84d is threaded into the plug 84a and carries an enlargement 842 having a bolt socket 84 adapted to engage the bolt 77 carried in the removable member 75. The socket- 84 is centered between a plurality of detents 84g carried by the axially extending fingers 840 on the retriever. Each of the detents extends axially inwardly of the retriever 84 and has a chamfered face 841: for engaging the head of A the bolt 77 and deflecting to permit the head to pass between the detents into the socket opening 84 of the retriever. FIG. 2 illustrates the bolt head engaged in the socket with the detents clamping the nether side of the bolt head and restraining the bolt to move with the retriever 84.

In operation, the apparatus A-l of this invention is connected to the kelly K and the drill string P by the connecting means having the preferred form of the threads a and 61a and those skilled in the art will recognize that connection of the closure apparatus does not affect or alter drilling by the rotary method with the apparatus shown somewhat schematically in FIG. 1. Drilling fluids are pumped through the kelly K, the closure apparatus A1, and the drill string P to the rotary bit utilizing conventional equipment. It may be appreciated that hydrostatic pressure is applied to the pressure fluid in the kelly K and the drilling mud acts on the valve 72 to move the valve 72 out of the valve seat 68. The force pressure resulting from the drilling mud acts against the valve 72 to oppose the force of the resilient means 80 urging the valve 72 into the valve seat 68. V 7

On reaching a predetermined hydrostatic pressure in the upper tubular member 60, the' force of the resilient means 80 is overcome and the valve 72 is moved away from the conforming surface of the shoulder member 68 clearing the axial passage means 64 of the obstruction of t the valve 72. It may be appreciated from the foregoing that the resilient means operates as fluid pressure biasing 7 means requiring'the fluid pressure to achieve a predetermined level to open the valve.

The valve 72 is maintained in alignment with the valve seat by the support member 72i moving within the sleeve that drilling fluids flow through the closure apparatus A-l of this invention to the. drill string therebelow. When the drill string P is disconnected from the closure apparatus A1 of this invention for any purpose, the operator reduoes the pressure of the mud pumping apparatus and the resilient means 80 moves the valve 72 into contact with the seal member 68 and thereby seals the passage means 64 through the apparatus A-l, as illustrated in FIG. 3. The closing of the apparatus A-l maintains a.

standing column of drilling fluid in the kelly K above the closure apparatus A1 when the drill string P is disconnected at the threads 61a. The retention of the drilling fluids in the kelly K reduces waste of expensive drilling fluids and even more especially reduces the dangers inherent with a slippery and wet drilling platform to the operators and laborers.

On reconnection of the drill string P to the closure apparatus A-l of this invention, drilling in the routine manner may be resumed by pumping drilling muds through the kelly K and forcing open the valve 72 as shown in FIG. 4. As will occasionally happen without forewarning, the drill bit may penetrate a reservoir under high pressure and gas or oil or a mixture of both will overcome the pressure of the column of drilling fluids standing in the drill string P. On such occurrence, reservoir pres sure tends to force the drilling fluids back through the closure apparatus A-1 and through the kelly K into the mud pumping apparatus. Such reverse flow may occur rapidly and can cause far-reaching damages and blowouts are quite dangerous to personnel and equipment. The closure apparatus A-I of this invention'operates tohold the drilling muds under blowout pressure in the drill string P because the high pressure fluids acting on the valve 72 from the drill string P urge the valve 72 more firmly into contact with the yieldable shoulder means 68.

It may be appreciated from an understanding of the structure illustrated in FIG. 6 that the greater the pressure in safely retaining the highly pressurized and dangerous blowout surging upward through the drill string P.

On occasion, it is necessary to run various items into the drill string P on a wire line to perform various functions in the well bore. For instance, a backotf shot may be run in the drill string P for jarring the drill string when it is stuck and will not rotate. This can be accomplished by using the retriever indicated generally at 84 to open the closure apparatus A-l as shown at FIG. 2 where the retriever is connected to the pipe 85. The retriever 84 is run into the kelly K on the pipe 85 and is engaged with the removable member 75. The member 75 is grasped by forcing the detents 84g aside the head of the bolt 77 on contact with the sloping faces 84h of the detents and the head is received in the socket hole 34 and the detents 84g are snapped by the springlike fingers 840 to the illustrated position of FIG. 2 so that the retriever is thereby engaged with the removable member 75. It may be appreciated that the bolt head shown in the drawings is hexagonal in shape and the socket 84 conforms to the head so that rotation of the pipe 85 rotates the retriever 84 and the attached removable member 75.

The threads of the bolt 77 in the member 75 are of left-hand configuration as opposed to the threads 76a on the plug 76 which are right-handed. It is not desirable to remove the bolt from the plug on rotation so that rotation of the bolt 77 in the customary direction tightens the bolt 77 in the plug 76 but disconnects the plug 7 6 from the threads 720 of the valve 72.

Attention is directed to FIG. 5 which illustrates an additional embodiment A2 of this invention featuring a valve body having bleed means therewith. There is shown in FIGS. 57 the upper and lower tubular members 6i} and 61 joined together with the sleeve 66 positioned therein for clamping the seal member 68 which serves as a valve seat for a valve 88. The valve 88 includes a valve body 88a which, in the preferred embodiment, is assembled from a plurality of separate elements to define the valve 88 and a conforming surface 88b adapted to contact the seal member 68 positioned in the passage means indicated generally at 64, The valve body 83a includes an insert 880 which insert has an upwardly extending fishing neck 88a and an axial passage 88e extends through the fishing neck 88:1. The insert 880 has a valve chamber 88] communicating with the passage 88c and a plurality of ports 88g communicate the valve chamber 88] in the insert 880 with the passage means indicated generally at 64 extending through the apparatus A-Z. The preferred embodiment includes three such ports 83g spaced equidistantly about the centrally located axial openings 88a as shown in FIG. 7 and spaced between the large ports are small weep holes 88!: which will be described in greater detail hereinafter.

The valve chamber 83 includes an annular shoulder 88: immediately below the large ports 88g which serves as a valve seat for a valve member 96 mounted on a valve shaft 91 which extends upwardly of the valve chamber 83 into the axial opening 88e. A coil spring 92 is loosely fitted about the guide rod 91 and bears against the upper surface of the valve 99 and is confined within the valve chamber by an annular shoulder 88 formed on the valve insert 880. The valve 90 includes an encircling chamfered surface 90a adapted to conform with a lower valve seat 88!: at the bottom of the valve chamber 887 in the valve 88. The valve seat 88k is preferably formed on an inner sleeve 881 which is threadedly engaged with the insert 380 at a set of threads identified at 88111. The threads 88m are similar to a set of threads 88n for joining the inner sleeve 881 to the valve body 88a as shown in the drawings. A plurality of evenly spaced web-like members 88p are connected to the lower end of the valve body 88a to define a plurality of ports 88g opening from just beneath the valve body 88a into an enlarged axial opening indicated at 88r. The enlarged axial opening 881' extends downwardly as shown in the drawings in a support member 88s connected to the web-like members 88p. A downwardly extending encircling lip 881 is terminated at one end in an outwardly extending, perpendicular shoulder 83a which extends to the sleeve 66 and the shoulder provides a bearing surface for receiving the resilient means indicated generally at 80. O-ring slots are provided at 88y and O-rings 88w are placed in the slots to limit the axial flow of drilling fluids along the exterior surface of the valve support member 88s.

The valve support means 88s is urged axially of the closure apparatus A-2 by the spring which is supported in the lower tubular member 61 in the same manner as is the embodiment A-1 shown in FIGS. 2-4.

In order to expand and further amplify understanding of the embodiment A-2 shown in FIGS. 5-7, operation of the closure apparatus of this invention will be described and referred to the closure apparatus A4. The embodiment A-2 is connected to the kelly K and the drill string P in the same way as the closure apparatus A and A-1. The handling of the drill string P by manipulations directed to the kelly K such as rotating, raising, and lowering the drill string P is done in a conventional manner. Drilling mud under pressure is applied to the kelly K and is communicated therethrough to the apparatus A-2 with the pressurized fluid maintaining a standing column on the exposed surfaces of the valve 88 which is seated against the valve seat 68 as shown in FIG. 5. The pressure of the drilling fluid bears on the valve 88 and on overcoming the fluid pressure biasing means 80, the valve 88 is moved from the conforming contact of the resilient member 68 into the chamber below the shoulder of the rubber member and pressure fluid passes about the valve body 88a. The drilling mud then flows through the ports 88q of the support structure 88s and passes through the axial opening 88r and thence into the lower tubular member 61. The lower tubular member 61 is connected to the drill string P and the fluid flows into the drill string P and onto the rotary drill bit connected thereto for lubrication in the customary manner. The flow as described above occurs on a pressure drop acting across the valve 88 suflicient to open the valve of the embodiment A-2 and is similar in operation to the closure apparatus A-l. The drilling mud passes through the ports 88g extending into the valve chamber 88] to fill the chamber and the Weep holes 8812.

The flow of pressure fluid is dependent on the biasing force exerted by the resilient means 80 positioned in the lower tubular member 61. Because of this, the drilling fluid pumping apparatus may be operated to reduce the pressure of the drilling mud in the kelly K and the valve 88 is returned to conforming contact with the valve seat and fluid flow is prevented. This step is customarily associated with the addition or removal of a joint of pipe from the drill string P which requires a disconnection of the drill string P from the lower end of the closure apparatus A2. As is well known to those familiar with the art, the drill string P is usually disconnected from the kelly K and additional joints of pipe are connected therebetween or the top joint of pipe in the drill string P is removed in accordance with the desires of the operator.

As mentioned previously, blowout-s may occur, tending to lift drilling mud through through the drill string P and the closure apparatus under the reverse pressure acting upwardly from the drill string P. Such pressure below the closure apparatus A-2 returns the valve 88 to the valve seat 68 and the kelly and fluid handling apparatus are protected from reverse flow of the drilling mud into the pumping apparatus, and the likelihood of damage resulting from the blowout .is thereby avoided. Of course, the pressure in the well bore may rise or increase for other reasons and the closure apparatus A-2 will prevent the pressure fluid in the well bore from acting on the fluid handling apparatus connected upstream of the invention.

On the occurrence of increased pressure in the well bore above the pressure of the drilling fluid acting on the valve 88, the valve 88 is closed as described above and the bleed means operates to enable the operator to have knowledge of the pressure in the drill string P. The valve 90 is lifted from the valve seat 88k and moved to contact the valve seat 881 at the upper end of the valve chamber 88 which movement compresses the coil spring 92 positioned about the guide rod 91 as shown in FIG. 6 and the guide 91 moves upwardly into the axial opening 88e of the central insert 88c. When the valve 90 is seated in the position shown in FIG. 6, the larger ports 88g connected to the upper end of the valve chamber 88f are sealed to prevent the flow of any drilling mud in the reverse direction. However, a small quantity of drilling fluid is bled through the weep holes 88h into the passage means 64 to bring the drilling fluid in the passage 64 slowly up to the pressure level of the drilling fluids below .the closure apparatus A-Z of this invention. It may be appreciated that the weep holes 88h are small in cross-sectional area and the drilling fluids are slowly transferred by the pressure of the drilling mud in the well bore so that the operator has sufficient time to shut down expensive equipment susceptible of damage from reversed flow of drilling muds and is able to connect pressure gauges or the like with the kelly K to thereby obtain a measurement of the pressure within the well bore itself. Accurate information about the pressure of the drilling muds within the well bore is of benefit to the operator in planning safe, precautionary operations for dealing with the sudden increase and to also pro- 'vide information for deciding whether or not such increase is in fact a dangerous blowout or merely results from some other cause. Whatever the cause, knowledge of the pressure enables precautionary moves to be adapted on the drilling platform for the protection of equipment and preservation of life.

Certain alterations may be included with the present invention and one such alternation involves the elimination of the Weep holes 88h shown in the embodiment A-2. A route for bleeding pressure fluids past the valve 90 when seated against the seat 881' may be obtained by machining or otherwise forming a bleed capillary at the surface of the valve chamber 88 through the valve seat 881'. Alternatively, the vertical travel of the valve 90 may be limited to a position short of sealing contact with the valve seat 88i so that leakage past the seat 881' and through the large ports 88g is possible. This may be achieved by positioning a spacer sleeve about the coil spring 92 sufficiently long to contact the shoulder 88 to hold the valve 90 below the 'seat 88i on compression of the spring 92: In other words, such means would provide an annular space between the valve 90 and the valve seat 88i to permit the bleeding of pressure fluid past the the valve and into the upper tubular member 60. Such 8 bleeding would likewise enable the operator to obtain pressure measurements of the pressure fluid below the closure apparatus A2.

Broadly, the present invention relates to'a device which automatically closes ofl a tubular member.

I claim: 9

1. A closure apparatus for controlling fluid flow through a kelly into a drill string and including'an arrangement whereby tools may be lowered through the.

closure apparatus, comprising: a (a) a member having a passage therethrough,

(b) means for connecting the member in fluid communication with the drill string and kelly,

(c) an annular shoulder located in said passage,

(d) a body having a conforming surface adapted to contact said shoulder to shut off fluid flow through said passage,

(e) guide means in said passage for aligning said body with said shoulder,

(f) resilient means for urging said body into conta-ct V with said shoulder to maintain. a standing column of fluid in the kelly,

g) said resilient means yielding on predetermined fluid pressure acting through the kelly whereby fluid may flow through said passage, (h) a plug threadedly engaged in the upper end of said body, and (i) a projection extending upwardly from said plug so that said plug may be threadedly disengaged and lifted upwardly out of said body whereby tools may be lowered through said body and into the drill string.

2. The invention of claim 1 wherein said plug includes port means in the upper end thereof and a spring loaded check valve mounted within said plug and normally preventing flow from said drill string through said port means, but which check valve may be actuated to open said port means to bleed fluid pressure from the drill string through said plug and which check valve acts upon the occurrence of a pressure surge from the drill string to close oif said port means in said plug.

References Cited UNITED STATES PATENTS 7 Hart -318 X CHARLES E. OCONNELL, Primary Examiner.

I. A. CALVERT, Assistant Examiner.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US403751 *Sep 25, 1888May 21, 1889 Implement for boring wells
US946684 *Dec 18, 1908Jan 18, 1910Charles C NeighborsBack-pressure valve.
US1462099 *Oct 29, 1921Jul 17, 1923Brown Charles HFishing tool
US1596260 *Mar 6, 1926Aug 17, 1926Alexander ThomsonBack-pressure valve
US1674055 *Apr 27, 1926Jun 19, 1928Margia ManningDrill stem
US1785271 *Jun 5, 1928Dec 16, 1930Oil Well Supply CoBack-pressure joint
US2750958 *Apr 27, 1953Jun 19, 1956Baker Oil Tools IncDrill pipe float valve
US3189046 *Nov 9, 1962Jun 15, 1965Nuclear Products CompanyPoppet check valve
US3191905 *Oct 12, 1962Jun 29, 1965Otis Eng CoGravity operated kelly foot valve
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3633668 *May 22, 1970Jan 11, 1972Baker Oil Tools IncDisaster valve
US3670766 *Apr 29, 1970Jun 20, 1972Dart Ind IncPoppet and valve assembly
US3698411 *Jul 29, 1970Oct 17, 1972Smith InternationalKelly foot valve
US3698426 *Jul 29, 1970Oct 17, 1972Smith InternationalMud saver valve and method
US3738436 *May 28, 1971Jun 12, 1973Smith InternationalMud saver valve and method
US3877529 *Jul 10, 1974Apr 15, 1975Smith InternationalMethod of assembling drill string using fluid saver valve
US4128108 *Apr 20, 1977Dec 5, 1978American International Tool Company, Inc.Mud retaining valve
US4364407 *Feb 23, 1981Dec 21, 1982Hilliard David RMud saver valve
US4901761 *Oct 6, 1988Feb 20, 1990Taylor William TClosure apparatus with pressure test device
US5165493 *May 10, 1991Nov 24, 1992Baugh Benton FMud saver valve
US5183068 *Jun 4, 1991Feb 2, 1993Coors Technical Ceramics CompanyBall and seat valve
US7743787Jul 9, 2007Jun 29, 2010CmvMud saver valve with magnetic latching
US8668015 *Nov 9, 2009Mar 11, 2014Gerald LeebDual check valve
Classifications
U.S. Classification137/327, 137/493.6, 175/218, 166/325, 137/515
International ClassificationE21B21/00, E21B21/10
Cooperative ClassificationE21B21/10
European ClassificationE21B21/10