US2162018A

US2162018A - Blow-out preventer

Info

Publication number: US2162018A
Application number: US144647A
Authority: US
Inventors: Melvin C Inge
Original assignee: Individual
Current assignee: Individual
Priority date: 1937-05-25
Filing date: 1937-05-25
Publication date: 1939-06-13
Anticipated expiration: 1956-06-13

Description

June 13, 1939. M c. INGE BLOW-OUT PREVENTER Filed June 13, 1939. M. c. INGE BLOW-OUT PREVENTER Filed May 25, 1957 3 Sheets-Sheet 2 June 13, 1939. M c. INGE BLOW-OUT PREVENTER Filed May 25, 1957 3 Sheets-Sheet I5 Patented June 13, 1939 UNITED STATES PATENT OFFICE 12 Claims.

This' invention relates to a device for use on wells such as oil wells and gas wells and relates more particularly to a blowout lpreventer for controlling a well during the drilling operations.'l

A general object of this invention is to provide a blowout preventer that is simple and practical and that is positive and dependable in operation. During the drilling of deep wells such as oil wells and gas Wells high uid pressures are frequently encountered in the earth formation penetrat-ed by the drilling tools. This pressure often develops very rapidly and blows out through the well around the drilling tools sometimes causing considerable damage. Control devicesknown as blowout preventers have been introduced for application to the upper ends of the Well casings for controlling the high pressures that may suddenly develop in the well when the drilling tools are in the well. Another object of this invention is toprovlde a blowout preventer embodying closure members or gates that may be quickly and readily operated into the well casing opening to seal about the ldrill pipe and thus control the well when high pressures develop in the well.

Another object of this invention is to provide a blowout preventer in which the gates are constructed and arranged so that the iluid pressures in the well tend to urge the gates into more effective sealihg'cooperation with the drill pipe and the seat of the blowout preventer body.

,Another object o f this invention is to provide a blowout preventer embodying novel and very dependable means for actuating `or forcing the gates into sealing cooperation with the body seat and the drill vpipe in such a manner that the well pressures may tend to maintain the fluid tight sealing engagement of the gates with the pipe and body'seat. 1 40. Another object of this invention is to provide a `b`owout preventer of the character mentioned in which the gates may be quickly and easily removed from the bodyfor the purpose of repair or for replacing the packing means.

Another object of this invention is to provide a blowout preventer of the character mentioned in which the gates may be removed through relatively small openings in the sides of the body whereby the body may be simple and inexpensive in construction and light in weight. p

A further object of this invention is to provide a blcwout preventer that embodies novel and particularly effective sealing means or packing means on the control gates.

The various vobjects and features of my invention will be fully understood from the'following detailed description of typical preferred forms and applications of my invention, throughout which description reference is made to the ac-L companying drawings, in which: 5

Fig. 1 is a vertical detailed sectional view of the improved blowout preventer provided by this invention illustrating thegates in elevation. in the closed positions and with broken lines illustrating the retracted positions of the gates. Fig. lo 2 is a fragmentary detailed sectional view taken substantially as indicated by line 2-2 on Fig. 1 illustrating one of the nuts and the adjacent parts Fig. 3 is a horizontal detailed sectional view ,taken substantially as indicated by line 3-3 on ll Fig. 1 with certain parts of the gates broken away to appear in horizontal cross section. Fig. 4 is va perspective view of one of the gates removed from the body. Fig. 5 is a vertical detailed sec-- tional view of one of the gates removed from go the device, being a view taken as indicated by line 5--5 on Fig. 3. Fig. 6 is a top view of a gate that may be employed in the blowout `preventer and that employs a modifled form of packing means and Fig. 7 is a fragmentary vertical g5 detailed sectional view taken as indicated by line '1 -1 on Fig. 6.

The blowout preventer of the present invention comprises, generally, a body l0 to be connected with a well casing C, closure members 30 or gates Il movable in the body i0-, means I2 for moving or actuating the gates I-l and packing means I3 on the gates Il for sealing with theI body lll and an object or pipe P extending through the hodv I0.

The body l0 is adapted to be applied to or connected with the upper end of a well casing C and is such that the various drilling tools maybe passed into and out of the casing without diiliculty when the gates Il are in the retracted 40 positions. The body I0 constitutes a housing or casing and is a hollow member or structure. A substantially vertical opening I4 extends through the body I0 and is intended to form a continuation of the opening of the casing C. A means is provided at the lower end of the opening I4 to facilitate the connection of the body IIJ with the casing C. In the simple case illustrated the lower portion of the body opening I4 is internally threaded to receive the threaded upper portion of the casing C. The upper portion of the opening Il may be internally threaded to receive the threaded parts of a nipple or casing extension. In accordance with the invention the body I4 has a transverse chamber I5 intersecting the opening 55 I4. The chamber I5 is generally rectangular and is defined by substantially horizontal upper and lower body walls I6, substantially vertical outer body walls I1 and substantially vertical body side walls I8. The several walls I 8, I'I, and I8 may be integral with the remainder ofthe body III. The chamber I5 is provided to contain the gates II and is proportioned so that the gates may be entirely retracted fromthe opening I4 to permit the normally close the openings I9. In'accordance with the invention a sealing surface or seat 22 is provided on the interior of the body I II around the opening I4 to be engaged by the gates II and their packing means I3. The seat 22 is annular and completely surrounds the body opening `I4 at the juncture of the upper wa-ll of the chamber I5 with the opening I4. The seat 22 is conical or partially conical and slopes downwardly and outwardly with respect to the central vertical axis of the 'opening I4.

The closure member; or gates II are shiftabie transversely or horizc `tally in the chamber I5 between positions entirely clear /of the opening I4 and positions where they extend across the opening I4 and engage about the pipe P. There are two gates II arranged at opposite sides of the central vertical axis of the device. The gates II are alike or complementary and in practice may be substantially rectangular `or block-like in shape. In the construction illustrated the gates II have fiat parallel upper surfaces 23 and lower surfaces 24 and at parallel side surfaces 25. The inner sides or opposing sides of the gates II may be fiat and vertical and carry the packing means I 2 as will be subsequently described. The vertical dimensions and the horizontal dimensions in both directions of the gates II are considerably smaller than the corresponding dimensions of the chamber I5.

" A vertical partially cylindrical groove 26 is provided on the inner or active side of each gate II. The grooves 26 register to receive the pipe P when the gates are operated inwardly or toward one another. A raised boss 21 is provided on the upper side 23 of each gate II. The bosses 21 are substantially semi-circular and are concentric with the grooves 26. The outer or peripheral surfaces of the bosses 21 are in the nature of sealing faces 28 and are adapted to cooperate with or oppose the seat 22 when the gates II are in their active or closed positions. The faces 28 are conical or partially conical and are adapted to evenly cooperate with or conform to the seat 22. The gates II may be cored out or recessed'from their outer sides as at 29 to reduce their weight and cost.

The means I2 for actuating the gates II is an important feature of the invention. In accordance with the invention the means I2 is operable to move the gates I I inwardly toward one another and at the same time shift the gates upwardly to bring the faces 28 in contact with or conformity to the seat 22 in such a manner that the upward force exerted by the fluid pressure in the casing -C may tend to more tightly urge the gates against the seat. The means I2 includes cooperable inclined surfaces or camsurfaces on the body I8 and the gates Il. Inclined surfaces 30 are provided on the lower wall I8 of the chamber I5 at opposite sides of the body opening I4. The surfaces 30 are vinclined downwardly and outwardly with respect to the vertical axis ofthe opening I 4 and are of thesame pitch and are equally spaced from the axis of the vopening I4. The body surfaces'30 are'of the same pitch or of substantially the same inclination as the conical body seat 22. The inclined surfaces 30 may be of substantial length' and may extend between the opposite side walls I8 of the body. The body I0 maybe thickened to present the surfaces 38 and the thickened portions of the body may present horizontal' orA transverse upwardly facing surfaces II which extend inwardly from the surfaces 30 to the wall of the body opening I4.

The gates II are provided with tails or downwal'dly projecting partsv 32 at their outer ends. The parts 32 project downwardly from the lower sides 24 of the gates and their rear sides may be flush with the rear sidcs oi' thc gates. Downwardly and outwardly Inclined surfaces 33 are provided on the inner sides of the parts 32 to cooperate with the body surfaces 30. 'I'he surfaces 33 are 'of the same pitch or inclination as the surfaces 30 and are of substantially the same vertical extent as tlie surfaces 30. The lower ends 34 of the parts 32 are fiat and substantially horizontal and are adapted to rest on the bottom wall I6 of the chamber I5 when the gates yII are in their retracted positions.

When the gates II are moved inwardly toward the drill pipe P the surfaces 33 come into contact with the surfaces 30 andthe cooperation of the

surfaces

33 and 30 cams or shifts the gates II upwardly and inwardly. The parts are related so that this compound movement or upward and inward movement ofthe gates II brings the sealing surfaces 28l into conformity or cooperation with the body seat 22. Thus the cam surfaces 3Il and 33 of the means I2 are operable to directl the gates v I I upwardly and inwardly against the seat 22 in such av manner that the force or pressurefexerted by the fluid `pressure in the casing C may tend to urge the faces 28 into tighter engagement with the seat 22.

The gate actuating means I2 further includes a mechanism for moving the gates II toward and away from the longitudinal axis'of the body opening I4. In the preferred construction illustrated in the drawings this mechanism is in the form of a screw means. As illustrated in the drawings screws S extend horizontally through the body chamber I5. The screws S have their opposite end portions rotatably supported by the body end walls I1 and are preferably supported between their ends. In the preferred form of the invention there is a screw S extending horizontally through the chamber I5 adjacent each side wall I 8 so that the screws S are adjacent the sides of the gates II.

It is preferred to construct each screw S `of two sections 35 .and 36, one section of each screw S having a right-handthread and the other section of each screw having a left-hand thread. The outerportions of the screw sections 35 are rotatably supported in sockets 31 in plugs 38. The plugs 38 are threaded in openings 39 in the end body walls I1. The plugs 38 may carry thrust bearings in the form of balls 40 cooperating with the ends of the screw sections 35. The

outer portions of the screw sections 36 are rotatably supported in openings 4| in the other end wall I1. Flanges 42 may be provided on the screw sections 36 to engage against shoulders in the openings 4| to limit the inward movement of the screw sections 36. Socket members 43 are arranged in the openings 4| to surround the screw sections 36 and bear inwardly against the anges 42. The members 43 are removably secured to the body lll by studs or screws 44. Packing glands 45 are carried by the socket members 43 to seal about the screw sections 36.

Releasable driving connections are provided between the inner or opposing ends of the secf 'tions 35 and 36 of each screw S. The inner ends of the screw sections 36 have polygonal sockets 46 and the sections 35 have polygonal end portions 41 cooperating with the sockets 46 for the transmission of rotation between the sections. The releasably coupled inner ends of the screw sections 35 and 36 are rotatably supported by bearing means. Bearing pins 48 are passed inwardly through openings 49 in the body walls I8. The pins 48 have flanges 50 seating inwardly against shoulders in the openings '49. Plugs 5| are threaded in the openings 49 to clamp inwardly against the pins 48 and retain them in position. Transverse or diametric openings 52 are provided in the inner portions of the bearing pins 48. the screw sections 35 and 36 are cylindrical and without threads and are rotatably supported in the openings 52 of the bearing pins 48. In this manner the bearing pins 48 rotatably support the screws S at points between their ends.

'I'he screws S are operatively interconnected to be turned or rotated in unison. A sprocket 53 is fixed to the projecting outer portion of each screw section 36 and a chain 54 operates over the sprockets 53 to connect the two screws S for simultaneous rotation. The screws S may be driven or rotated in any suitable manner, for example, they may be rotated bv hand, by an electric motor, by an engine, or 4any other source of power. The outer portion 55 of one or both of the screws S may be polygonal to facilitate the connection of a power source with the screw or screws. l

The gate actuating means i2 further includes nuts N threaded on the screws S and shiftably associated with the gates to eiect the movement of the gates into and out of cooperation with the pipe P. Grooves 54 are provided in the opposite sides 25of the gates to cooperate with or partially receive the nuts N. The grooves 54- may have iiat substantially vertical inne! walls and flat parallel side walls 54a. The grooves 54 are inclined, that is, their side walls 54a are inclined downwardly and inwardly relative to the longitudinal axis of the body opening |4. Theseveral grooves 54 have the same degree of inclination. The grooves 54 preferably extend between the upper and lower ends of the gates A nut N is provided for cooperating with each groove 54, there being a nut N on each screw section 35 and 36. In accordance with the invention the lnuts N are sectional to permit the easr removal of the gates from thc body I0. The nuts N each include an inner section 55 and an outer section 56. The inner sections 55 are substantially rectangular block-like parts and the outer sections 56 are block-like members arranged against the sections 55. Inwardly extending anges 51 are provided at the opposite The inner or connected portions of 56 and are threaded in sockets 62 in the inner sections 55 to detachably connect the nut'sec-` tions. The heads of the screws 58 are countersunk in the openings 59. The nuts N are elongate and are partially received in their respective grooves 54 with their greatest dimensions extending' longitudinally of the' grooves. The end surfaces of the anges 61 of the outer sections 56 slidably cooperate with the side walls 54n of the grooves while the sections 55 may be clear of the grooves. The nuts N are of greater depth or thickness than the grooves 54 and project from the grooves to have the outer surfaces of the sections 56 adjacent to or in sliding cooperation with the side walls I8 of the chamber I5. This engagement of the nuts N with the walls |8 of the chamber 5 guides the gates I and prevents lateral shifting of the gates.

As mentioned above, the nuts N are threaded on the screws S. The inner sections 55 of the nuts N have tube halves 60 inset in their outer surfaces and the outer nut sections 56 have complementary tube halves 66 inset in their inner surfaces to oppose the tube halves 66 on the inner sections. The tube halves 66 of the nut sections 55 and 56 are related to constitute tubes for receiving the screws S and in the preferred con struction they are of suflicient length to project beyond the opposite sides of the nuts N to have substantial engagement with the screws S. The tubes formed by the halves 60 are internally threaded and their threads cooperate with the threads ofthe screw sections 35 and 36. The tube halves 66 may be welded to their respective nut sections 55 and 56, it being understood that they may be formed integral with the sections, if desired. The opposite sides of the nuts N may have suitable slight clearance with the side Walls 54a of the grooves 54.

Upon rotation of the screws S the threads of the screw sections 35 and 36 and the tube halves 60 cooperate to eiect retraction or advancement of the gates depending upon the direction of rotation of the screws. In the case of the advancement of the gates toward the pipe P the nuts N cooperating with the inclined grooves 54 tend to wedge or shift the gates upwardly as well as horizontally. Thefbosses 21 cooperating with the upper wall of the chamber |5 prevent this upward movement of the gates throughout the ini` tial portion of their movement. However, when the upper edges of the boss faces 26 reach the lower edge of the seat 22 the gates may move upwardly as weil as horizontally. At this time the surfaces 33 come into engagement with the surfaces 36 and their cooperation with the surfaces 30 cams or shifts the gates upwardly andV inwardly with respect to the longitudinal axis of the opening I4. Thus when the screws S are rotated to actuate the gates the gates are moved inwardly toward one another and then upwardly and inwardly toward one another, as they approach the pipe P.

The packing means I3 is provided to assure a fluid-tight engagement of the gates with the pipe P and the seat 22 and a duid-tight cooperaticn of the active sides o f the gates when the gates are actuated into engagement.

The seat engaging faces 28 of the gates are provided with grooves 63. 'I'he grooves 63 are spaced between the upper and lower edges of the faces 28 and are curved concentric with the faces. In the case illustrated the grooves 63 are rectangular 'in cross section it being understood that they may be dove-tailed if desired. A relatively narrow lip or ridge 64 may project from the inner or activel face of each gate II. The ridges 64 extend along' the margins of the inner faces of the gates and continue along the faces of the gates at the upper and lower ends of the grooves 26. In the form of the invention illustrated in Figs. 1 to 4, inclusive, of the drawings, the packing I3 comprises an integral body 65 of packing material covering the active face of each gate I I and occupying the -groov'e 63 of its respective gate.

Y the outer faces o ffthe ridges. Screws 61 or other suitable securing members may attach the packing bodies 85 to the gates I I.

A strap or s'trip 68 is integrally joined with eacli packing body 65 adjacent one of its upper outer corners and curves outwardly or rearwardly and then inwardly to its other upper corner to occupy the groove 63 of the gate. The free ends of the strips 68 are folded across the faces of the packing bodies 65 and may be secured to the gates I I by screws 69. The portions of the straps 68 lapped over the packing bodies 65 may be inset or recessed in the packing bodies. Pins 16 may be passed through spaced openings in the bosses 21 and the strips 68 to assist in retaining the Vstrips in the grooves 63. The strips 68 preferably project slightly from the grooves 63 to better seal with the seat 22. It will be observed that the packing bodies 65 completely cover the active inner sides of the gates I I and the grooves 63 to fully seal with the pipe and the seat 22 and to seal one against the other when the gates are inthe closed positions. There are no seams-or joints in the packing 'bodies 65 to. permit the escape of fluid under pressure. During the drilling operations the gates I I are normally in their out or retracted positions indicated by the broken lines in Fig. 1 of the drawer? ings. When in these positions the gates II are completely clear of the opening I4 and, therefore, do-not interfere with the operation or passage of 'the drilling tools through the casing C. In the event that heavy pressures suddenly develop in the well the screws S are rotated in a direction to actuate the gates II inwardly. The threads of the screw sections 35 and 36 and the tube halves 68 cooperate to feed the nuts N inwardly along the screws. The inwardly moving nuts N cooperate with the grooves 54 to force the gates II inwardly toward one another. During the initial inward movement of the gates I I the upper sides of the bosses 21 may engage the upper wall of the chamber I5 to prevent upward movement of the gates. When the upper margins of the faces 28 reach-the lower margin of the seat 22 the gates II may move upwardly as well as inwardly. At this time the surfaces 33 come into camming engagement with the surfaces 30. 'I'his cooperation of the surfaces 33 with the surfaces 30 coupled with the cooperation of the nutsN with the inclined walls 54* of the grooves 54 effects the upward and inward movement of the gates I I.

taneous.

This movement of the gates II is, of course, simul- The upward and inward movement of the gates Il continues until the faces 28 are in conformity with the seat`22 at which time the strips 6B may tightly seal against the seat. The

surfaces 33 remain in engagement with the surfaces 30 when the'gates II reach this position.

When the faces 28 are in conformity with the seat 22 the inner sealing surfaces of the packing bodies 65 are in cooperation and the concave parts of the packing bodies occupying the grooves 26 are in sealing engagement with the pipe P.

Further turning force applied to the screws S may tend to bring the packing bodies 65 in'to tighter cooperation and into tighter sealing engagement with the pipe P and may further compress the strips 68 against the seat 22. The upward fluid pressures in the casing C are, of course, exerted against the lower ends of the gates I I which close if the opening I4. 'I'he force or pressure exerted by the fluid under pressure in the casingC merely Closing of the casing C by the gates II of course f brings the well under control.

The gates II may be easily retracted from the opening I4 by merelyrotating the' screws S. During the initial outward movement of the gates II the faces 28 or the strips 68 orv both cooperate /with the seat 22 to cam the gates downwardly and downwardly. At. this timethe surfaces 33 slide downwardly `and outwardly on the surfaces 3l.

This may bring the ends 34 in engagement withl the bottom wall of the chamber I5 and-the lower surfaces 24 into engagement with theshoulderBI, at which time the Vdownward movement of the gates is stopped. Further 'rotation oi the screws S to retract the gates II results in` outward Lmove` ment of the gates to their retracted positions illustrated by the broken lines in Fig. 1.

When it becomes necessary or desirable. to inspect or replace the packing .bodies 65 on the gates II the plates 20 at one side of the-body III are removed. Upon removal of a plate 20 the screws 58 of the adjacent nut N are accessible for engagement by wrenches and may be easily unscrewed so that the outer nut section 56 may be` removed. Following the removal of the outer nut section 56 the inner section 55 is moved inwardly to disengage its thread portion from the thread of the screw section 35 or 36. The nut N accessible at the other uncovered opening I9 is treated in a like manner. This disengages the nuts N from one of the screws S. The plug 38 at the end of that screw is removed whereupon the screw section 35 may be withdrawn from the body I Il. The socket member 43 at the other end of the screw S is then removed from the body'whereupon the screw section 63 may be withdrawn from the body. Upon the removal of the screw S the two'gates I I may be individually withdrawn outwardly through the openings I9. As the nuts N at the other side of the device are not permanently secured to the gates the gates may be merely moved laterally out of engagement with the nuts remaining in the body. In this manner the gates II may be easily removed from the body for inspection, repair,etc. It is believed that it will be understood how the gates may be inserted in the body and the several parts reassembled to condition the blowout preventer for further u se.

Figs. 6 and 7 illustrate a gate IIu having a slightly modified form of packing means I3*-. The gate II1 is of the full shut-off type; that is, two gates IIl of the character illustrated in Figs. 6 and 7 may be employed in place of the gates II to control the well when the string oi pipe P is withdrawn from the well or is not extending through the blowoutpreventer. It is to be understood that the packing means I3 and I3a may be employed on either form of gate I I or I Ii.

The gate IIa is substantially identical with the gate II described above except that its inner face is at and devoid ofthe groove 26. The inner or active face of the gate IIa may have a ridge similar to the above described ridge 54 which ridge may extend along the entire margin of the inner face of the gate. The sealing face 28 of the gate II may be similar to the sealing face 2Q and is provided to cooperate with the seat 22 of the body I0. A curved elongate depression or groove 63a is provided in the face 28a. The groove 63a is V-shaped in cross section, having two walls converging outwardly to the face 28a, one wall being substantially vertical and the other being substantially horizontal. The groove 63a is spaced between the upper and lower margins of the face 28a and extends between the opposite ends of the face.

The packing means I3a illustrated in Figs. 6 and 7 includes a packing body 65L covering the active inner face ofthe gate I Ia and a strip or loop 68"' for fitting the groove 63a. The packing body 65a preferably covers the entire inner face of the gate IIa and is preferably one piece or integral. The loop 68a has its opposite ends integrally joined with the packing body (i5a and curves outwardly or rearwardly from the packing body 65a at its upper end to nt the groove 638. The loop Iilla is triangular shaped in transverse cross section, having inwardly convergent sides cooperating with the walls of the groove 63a and having a at outer surface for cooperating with or sealing against the body seat 28. The loop 68a may be sprung into the groove 63a when the packing means is assembled on the gate IIa and may be secured in place by pins 'IIJa arranged in openings in the gate IIa to pass through openings in the loop 68a. The packing body 65a and its loop 68 are readily removable for replacement when worn. Figs. 6 and 'l'has substantially the same function and operation as the gates II described above.

Having described only typical preferred forms and applications of my invention, I do not wish to be limited or restricted to the specific details herein set forth, but wish to reserve to myself any variations or modifications that may appear to those skilled in the art or fall within the scope of the following claims.

Having described my invention, I claim:

1. A blowout preventer for use on a well casing comprising a body having an opening for registering with the opening of the casing, a seat in the body around the body opening, shiftable gates in the body, means for moving the gates toward one another in a direction transverse of the longitudinal axis of the body opening to engage about an object in the body opening, and means for shifting the gates upwardly during The gate IIa illustrated in around the opening, movable gates in the body,

means for moving the gates inwardly toward the opening in a plane substantially normal to the longitudinal axis of the opening to seal with one another and engage about an object inthe opening, and means for shifting the gates upwardly during their inward movement to engage against the seat, the last mentioned means including cooperable cam faces on the body and the gates.

3. A control device for use on a well casing including a body having an opening in communication with the interior of the casing, a substantially downwardly lacing seat in the body around the opening, movable gates in the body, means for moving the gates inwardly toward the opening in a plane substantially normal to the longitudinal axis of the opening to seal with one another and engage about an object in the opening, and means for shifting the gates upwardly dui'- ing their inward movement to engage against the seat, the last lnentioned means comprising inclined faces in the body facing outwardly with respect to the opening, and inclined faces on the gates facing inwardly with respect to the opening and cooperable with the rst mentioned faces.

4. A control device for use on a well casing including a body having an opening in communication with the interior of the casing, a downwardly facing seat in the body around the opening, movable gates in thebody, means for moving the gates inwardly toward the opening in a direction at substantially right angles to the opening, and cam means for shifting the gates upwardly against the seat during their inward movement.

5. A control device for use on a well casing including a body having an opening in communication with the interior of the casing, a downwardly facing seat in the body around the opening, movable gates in the body, screw means for moving the gates inwardly toward the opening in a direction at substantially right angles to the opening to seal with one another, and cam means for shifting the gates upwardly against the seat during their inward movement.

6. A control device for use on a well casing including a body having an opening in communication with the interior of the casing, a downwardly facing seat on the interior of the body around the opening, movable gates in the body, rotatable screws carried by the body, nuts having threaded engagement with the screws and shiftably cooperating with the gates to move them inwardly into the opening to seal with one another when the screws are rotated, and cam parts on the gates and body cooperable to shift the gates against the seat during the inward movement of the gates.

7 A control device for use on a well casing including a body having an opening in communication with the interior of the casing, an inclined seat on the interior of the body around the opening, movable gates in the body having inclined surfaces pitched in the opposite direction to the seat, means for moving the gates inwardly toward the central longitudinal axis of the opening to bring the gates into sealing cooperation comprising actuating parts cooperating with the said inclined surfaces, and cam means for shifting the gates upwardly. on the actuating parts during inward movement of the gates to bring the gates against the seat.

8. A control device for use on a well casing including a body having an opening in communication with the interior of the casing, a downwardly facing seat on the interior of the body around the opening, movable gates in the body having grooves inclined upwardly and outwardly with respect to the longitudinal axis of the opening, nuts shiftably cooperating with the grooves, screws actuating the nuts to shift the gatesinwardly with respect to the longitudinal axis oi' the opening, and cooperable cam parts on the body and gates operable to shift the gates upwardly on the nuts to engage the seat.

9. A control device for a well casing comprising a body having an opening in communicationv with the interior of the casing and a chamber intersecting the opening, gates shiftable in the chamber, a downwardly facing inclined seat on the interior oi.' the body around the opening,

toward the axis of the opening. and cooperable inclined surfaces on the body and gates for shifting the gates upwardly relative to the nuts to engage the seat.

10. A control device for a well casing comprising a body having an opening incommunication with the interior of the casing and a chamber intersecting the opening, gates shiftable in the chamber, a downwardly facing inclined seat on the interior. of the body around the opening, screws extending through the chamber, nuts on the screws cooperating with the gates, means for rotatingthe screws to shift the gates into and out f the opening, each nut including sections, and means detachably securing together the sections, the sides of the body having access openings rendering the detachable securing means accessible 11. A control device for a well casing compris' ing a body having an opening in communication with the interior of the casing and a chamber intersecting the opening, gates shiftable in the chamber, a downwardly facing inclined seat on the interior of the body around the opening,

' screws extending through the chamber, means supporting the end portions and the intermediate portions of the screws for rotation, nuts threaded on the screws and having cooperation with the opposite sides of the gates to eiect their movement into and out of the opening, means interconnecting the vscrews Afor simultaneous rotation, and cam means for shifting the gates upwardly against the seat' when the gates are moved inwardly by the nuts.

12. A control device fonA a well casing comprising a body having an opening in' communication with the casing, a chamber intersecting the opening and access openings in a side wall of the chamber at opposite sides of the opening, a seat on the interior of the body around the opening, gates shiitable in the chamber, cam means for moving the gates against the seat during shifting of the gates into the opening', and means for shifting the gates comprising screws passing through the chamber, each screw including two sections, means-removably supporting the opposite ends of the screws and permittinglremoval of the sections of the screws from the ends of the chamber, sectional nuts threaded on the screws and shiftably cooperating with the `gates to move the same, and means for rotating the screws to shift the gates, the nuts including sections, and means detachably connecting the .nuts sections manipulable through said access openings whereby the nuts may be released from the screws to permit removal of the screws and removal of the gates through the access openings atright` angles to the screws. Y

MELVIN C. INGE.