US3151839A

US3151839A - Two-way flapper-type valve

Info

Publication number: US3151839A
Application number: US187603A
Authority: US
Inventors: James D Mott
Original assignee: Individual
Current assignee: Individual
Priority date: 1962-04-16
Filing date: 1962-04-16
Publication date: 1964-10-06
Anticipated expiration: 1981-10-06

Description

Oct. 6, 1964 J. D. MOTT TWO-WAY FLAPPER-TYPE VALVE 3 Sheets-Sheet l Filed April 16, 1962 JH/HES D. /HOTT INVENTOR.

A T TORNE'YS Oct. 6, 1964 J. D, MoTT Two-WAY FLAPPER-TYPE VALVE 3 Sheets-Sheet 2 Filed April 16, 1962 l/V55 D. MT'T INVEN TOR.

ATTORNEYS Oct. 6, 1964 J. D. MOTT 3,151,839

TWO-WAY FLAPPER-TYPE VALVE Filed April 16, 1962 K 3 Sheets-Sheet 3 P $23. 5 a 3 u ATTRNEYS United States Patent O 3,15L839 TWG-"WAY FLPiER-i Y PE VALVE .lames D. Mott, Houston, Tex., assigner to Cicero C. Brown, Houston, riex. Filed Apr. 16, 1%2, Ser. No. 187,603 13 Claims. (Ci. 251-3531) This invention relates to improvements .in dapper-type valves, and more particularly to a dapper-type valve capable of shutting oft a conduit against uid pressures exerted in opposite directions through the valve.

Flapper-type valves of the type commonly employed in oil and gas well equipment for closing-od the bore of a pipe string or other well equipment conduits commonly operate as one-Way check valves. Commonly they are hinged to swing across the bore of the conduit to shut off uid how in one direction, while permitting dow of duid in the opposite direction. in conventional well equipment, the valve is normally operative to permit fluid dow downwardly through the bore of the pipe or other equipment while preventing upward now. Generally, the valve is resiliently biased toward the closed position and will commonly be held in the open position by a tubular mandrel or so-called stinger mounted on an inner string ot pipe to extend through the valve body to force the dapper valve to one side, thereby usually allowing well uids to ilow through the bore of the stinger. On Withdrawal of the stinger the valve is freed to swing back to its closed position under the biasing force and under pressure from below.

Such valves, as noted, conventionally operate in only one direction. There are, however, many duid-flow conditions existing, particularly in oil well operations, where it is essential that a valve should remain closed even when the stinger has been withdrawn and the ditferential pressure across the valve is in the direction tending to open it. As one example, it is common practice to install a dapper-type valve in the pipe string below a well packer employed to seal orf a well bore between vertically spaced uid-containing zones. Normally, a stinger run on the production tubing will extend through the packer to hold the valve in open position to permit production from a lower producing zone to ilow upwardly through the production string. When, for any reason, the stinger must be withdrawn, the valve will swing closed if the pressure from below exceeds that above the valve. However, if the pressure above the valve, as from a higher zone, or by reason that the head of mud or huid in the tubing above the valve exceeds the pressure below the valve, the latter will swing open. inter-mixing of the uids from two separate zones, a condition absolutely forbidden by State production control regulations. In the other case, opening of the valve might result in the dumping of a large volume of mud or other undesirable uid into the well where it might seriously damage the production capabilities of a lower zone.

Accordingly, it is a primary object of this invention to provide a two-way tlapper-t pe valve which will automatically shut-oit under fluid pressure diterentials exerted in either direction across the valve.

An important object is the provision of a two-way apper-type valve which operates as a conventional swing check valve to shut oli automatically against higher pressure from below the valve and which includes a pressurefluid actuated keeper or lock mechanism operable automatically to hold the valve in closed position in response to higher pressures above the valve.

in accordance with one embodiment, this invention comprises a tubular valve body equipped with a appertype valve biased to swing across the lower end of the bore L1 the one case, the result would be i SLSQ Patented Get. 6, 1964 ice of the valve body to normally close the same against higher huid pressures lfrom below. The valve body is enclosed by a slidable cylinder which carries a keeper member extending beneath the dapper-type valve and movable upwardly into a position 4holding the dapper-type valve closed in response to' pressures above the valve exceeding pressures below the same. For accomplishing this function, the valve body is provided with ports communicating the bore thereof with the cylinder. The latter is constructed to have an effective area exposed to fluid pressure in the valve bore which is greater than the area of the dapper-type valve which, when in the closed position, is exposed to the same pressure. By reason of this difierences in areas, the total force applied by a given uid pressure to the keeper member urging it to the valveholding position will exceed the force exerted in the direction tending to swing the dapper-type valve to the boreopening position and will thus maintain the valve in its closed postion.

Other and 4more speciiic objects and advantages of this invention will become more readily apparent from the following detailed description when read in conjunction with the accompanying drawing which illustrates a useful embodiment in accordance with this invention.

In the drawing:

FIGS. to 5, inclusive, are similar `longitudinal quartersectional views of the valve illustrating the parts at difierent positions during several stages of operation thereof;

FIG. 6 is a cross-sectional View taken along line 6-6 of FIG. 5;

FIG. 7 is a fragmentary view of a detail of the Valve; and

FIG. 8 is a diagrammatic view of an oil or gas well illustrating one particular application of the valve, in accordance with this invention.

Referring to the drawing, the valve structure is designated generally by the numeral l@ and includes a tubular support body il having an arial bore 12, and having an externally threaded socket i3 at its upper end receivable in an adapter nipple or collar by which the valve structure may be secured to the lower end of a well pipe P, which may also be the tail pipe of a well packer, or like well equipment. Socket 13 is made somewhat larger in 4internal diameter than bore t2, so that the bottom of socket 13 delines a tapered internal shoulder 1S. The exterior of body il, below socket i3, is reduced somewhat in diameter to define a downwardly tapered external shoulder 15 at a point generally opposite internal shoulder 15. The lower end of support body l1 is externally threaded to be coaxially received in the upper end of the bore 1S of a tubular valve casing 17, the diameter of bore i3 being such as to make it hush with bore 12 of the support body. The lower end of valve casing 17 defines a tapered annular vaive seat i9 for engagement by the upper face of dapper-type valve 2t? which is hingedly mounted at one side of the valve casing for swinging across bore 18 between positions opening and closing the bore. Valve 2@ is of generally circular shape and, as best seen in FIG. 7, is provided with a pair or laterally extending spaced-apart perforate hinge lugs 21-21, in which is journalled a hinge pin 22. A support stem 23 is slidably mounted in a longitudinal slot 24 milled into the exterior of valve casing t7, slot 24 beingmade generally square in cross-section (FG. 6). Stem 23 extends upwardly through an opening 25 provided in the bottom of slot 24. The lower end of stem 23, which projects through opening 25, carries an eye 26 which is positioned between hinge lugs 21-21 and is adapted to receive hinge pin 22. A set screw Z7 locks eye 26 to hinge pin 22 to hold the latter stationary and thereby permitting valve Ztl to swing about the hinge pin. A pair of coil springs 2%-28 are suitably mounted about the opposite ends of the hinge pin and engage valve to impart thereto a biasing force urging valve 26 toward seat 19, the position closing bore 18. The upper end of stem 23 is threaded into a square nut 29 dirnensioned to slidably fit slot 24 and thereby prevent rotation of the stem 23 in the slot. A coil spring 3i? surrounds stem 23 and is disposed in compression between the bottom 31 of slot 24 and nut 29 to normally bias the stem upwardly in the slot, as illustrated particularly in FIGS. l to 4.

A cylindrical sleeve 33 is mounted about the exterior of valve casing i7 to be slidable thereon. rl`he upper end of sleeve 33 is secured by means of a set screw 34 to a tubular cylinder head 35 slidably disposed about the exterior of body il. An internal seal packing 37 is mounted in the bore of cylinder head 35 to form a slidable seal about the exterior of body 11. A second seal packing 3S seals between the exterior of the cylinder head and sleeve 33. The upper end of valve casing 17 is provided with an external seal packing 39 forming a slidable seal between the exterior of the valve casing and the inner wall of sleeve 33. A seal packing 4t? is mounted to seal between the interior of valve casing and the exterior of body 11.

The space provided between sleeve 33 and the exterior of body 11 is closed at its ends by cylinder head 35 and the upper end of valve casing i7 and the thus enclosed space denes an expandible pressure chamber 41 which is in iluid pressure communication with bore i2 through one or more ports 42. extending through the wall of body il at a point just above the upper end of valve casing 17. lt will be evident that chamber 4l will have an effective area exposed to pressure fluid admitted through ports 42 which is considerably greater than the edective area of valve 20 exposed to the same pressure fluid when valve 24) is in the closed position.

Sleeve 33 has a length such that when cylinder head 3S is in its lowermost position, substantially abutting the upper end of valve casing 17,-the lower end portion of the sleeve will extend below valve" Ztl when the latter is in its fully opened position, as illustrated particularly in FIG. 1. The lower end of sleeve 33 has inserted therein an annular keeper 43 which is secured to the sleeve by means of set screws 44. Keeper 43 has a bore 45' which is substantially ush with bores 12 and i3. As best seen in FGS. 3 and 4, keeper 43 will be disposed to extend laterally beneath valve 2t? and to hold the latter in its closed position when sleeve 33 has been elevated in a manner to be subsequently described.

A tubular mandrel or stinger Sti is dimensioned to be slidably insertable through bores 12 and i8 and is adapted to be connected to a tubing string T by which the stinger is moved longitudinally through

bores

12 and 18. The upper end portion of stinger 5@ is reduced in diameter at 51 to define an upwardly facing external shoulder 52 spaced from a downwardly facing upper shoulder 53, which may be defined, as illustrated, by the lower end of a collar 54 by which the stinger is connected to tubing string T. Slidably mounted on reduced diameter portion 51 is a tubular packing carrier 55 slidably receivable in `socket 13 and having mounted on its exterior the seal packing S6 which is adapted to form a fluid-tight slidable seal with the inner wall of socket 13. The lower end of packing carrier 55 denes a tapered shoulder 57 adapted to engage internal shoulder 1S of the support body, thereby limiting downward movement of the packing carrier. The latter, when seated on shoulder 15, will limit downward movement of the stinger through the abutment of shoulder 53 with the upper end of the packing carrier. Lower shoulder 52 serves as a stop to permit a limited amount of longitudinal movement of packing carrier 5S relative to the stinger, for purposes which will appear subsequently. The lower end of stinger 59 carries external packing 58 adapted to slidably seal with the wall of bore 18 of the valve casing.

The above described structure is operated in the following manner: It will be assumed first that stinger 50 is in the position illustrated in FIG. 1, in which the stinger has been inserted to its full extent, at which the lower end of the stinger will project through the lower end of bore 18 of the valve casing and will have forced valve Ztl to one side, as shown in FlG. 1, holding the valve in the open position against the biasing force of springs 23. Packing carrier 55 will be seated on shoulder 15 and the downward movement of the stinger will be limited by the abutment of shoulder 53 against the upper end of the packing carrier, as shown. Sleeve 33 will be in its lowermost position with keeper 43 positioned just below the lower ends of stinger Si? and lthe open valve Ztl. Valve support stern 23 will be biased to its ful-ly retracted position, as shown in FlG. 1.

The structure will be installed in the bore of well casing C, for example, on the tail pipe oi a conventional well packer W (FIG. 8) which seals ott" the well bore between the packer body B and casing C.

With the stinger fully inserted, as in FlG. 1, packing Se will seal olf between body l1 and stinger Si) and prevent communication of pipe P with ports 42 and the area below the valve. Although ports 42 and cylinder head 35 are exposed to the pressure below the valve, this pressure will not move sleeve 33 because the exterior of cylinder head 35 is also exposed to this same pressure and the forces balance exactly and there is no resultant force.

When it is desired to close valve 2t?, stinger 5d will be elevated by raising tubing T. When the stinger is moved upwardly suihciently so that its lower end has retracted inside the lower end of bore 1S, valve 2i) will swing to the closed position on seat 19 in response to the force of springs 28 (FIG. 2). At this stage, packings 56 and 53 will seal off the bores 12 and 1S from the pressure in pipe string P and will also isolate valve 2i) from this pressure. This provides an important safety feature in that the pressure cannot raise keeper 43 until valve 20 is fully closed, thereby preventing accidental damage to the dapper-valve through premature raising of the keeper member. As the stinger is further elevated (FIG. 3), packing carrier 55 and packing 56 will move upwardly out of socket 13 while packing 5S still seals oilE bore 18 below ports 42. With packing 56 out of sealing engagement with socket 13, pressure between tubing T and pipe string P will be admitted between body il and stinger S0 to ports 42, and thence to the interior of chamber 41. The pressure thus admitted will act on cylinder head 35 to lift sleeve 33, moving keeper 43 upwardly until it engages the bottom face of Valve 2@ and as long as the keeper is held in this position, it serves to lock valve 2t) in the closed position. The stinger may now be withdrawn entirely from body l1 and valve casing 17 (FIG. 4). lt will be seen that if the pressure below valve Ztl is greater than that in pipe P, valve Ztl will remain closed in the normal manner, due to the pressure differential operating in the closing direction. This is the normal operation of the dapper-type valve in well equipment of the general character described. On the other hand, if the pressure in pipe P is greater than the pressure from below valve Zi), this pressure will act on the effective area of valve 20, which is deiined by the cross-sectional area of the upper face of valve 2@ which is exposed to this pressure will also enter Chamber 41 and act upon the effective area of cylinder head 35. As this latter area is greater than the effective area of valve 2i? which is exposed to the pressure, obviously sleeve 33 will be maintained in its elevated position holding keeper 43 against the bottom surface of valve Ztl and retaining the latter in its closed position.

Should the pressure conditions change, that is, the pressure from below becoming greater than the pressure above, valve 2@ will remain in its closed position in response to the upwardly directed pressure differential, despite the fact that this pressure from below may act on the upper surface of cylinder head 35 and thereby move sleeve 33 downwardly so as to lower keeper 43 out of engagement with valve 20 to a position such as shown in FIG. 2. Under these circumstances, to re-open the valve, it is only necessary to run stinger Si? back through bores 12 and i8 into engagement with the upper face of the valve and, by exerting downward pressure on the valve by the weight of the tubing string, force valve 2i? to swing back to the open position, as shown in FIG. 1, and thereby re-open the tubing string to luid ilow therethrough.

When, however, the pressure above is greater than that below the valve and it is desired to re-open valve 2o, stinger Si) will be run back into pipe string P and through the bores of support body 11 and valve casing 17 until the lower end of the stinger engages the upper face of valve 20. Downward pressure exerted through the stinger will then move valve member 20, keeper 43 and sleeve 33 downwardly to the full extent of their travel, this action compressing spring 39 as stem 23 is forced downwardly in slot 24. This stage is shown in FIG. 5. While the downward movement of the valve is taking place, packing carrier 55, carrying packing Se, will re-enter socket i3 and will seal oft the pressure in pipe string P from chamber 41 and from valve 20. When valve 2i) and keeper 43 have moved downwardly to the full extent of their travel to the position indicated in FIG. 5, the stinger is again pulled back a suiiicient distance until the lower end thereof reenters the lower end of bore i8, thereby permitting stem 23 to retract and pull valve Ztl back to its original position, at which point the valve will swing shut on seat 19, the parts being returned substantially to the positions illustrated in FIG. 2. Packing 56 will remain in socket 13 as stinger 56 may move up relative to packing carrier 55 for the short distance required to release valve Ztl, and packing 56 will seal ot ports 42 from pressure in pipe F so as to prevent upward movement of sleeve 33. Thereupon, the stinger will be moved downwardly again forcing valve 20 to swing to the open position, shown in FlG. 1. This can occur because at this stage of operations, keeper 43 will be in its lowermost position, the pressure having been relieved from chamber #il when packing 58 has moved below the end of valve casing 17 in attaining the position illustrated in FG. 5 and packing 56 having sealed on ports 42 from pressure above the valve. With the stinger back in the position shown in FIG. 1, with the valve open, the bore of tubing T will be opened again to uid now through the tubing.

It will be understood that various changes and modications may be made in the details of the illustrative embodiment within the scope of the appended claims but without departing from the spirit of this invention.

What I claim is:

l. 1n combination with a tubular body having a through bore, and a apper type valve hingedly secured to one side of said body for swinging movement between positions opening and closing said bore, means carried by the body for supporting said valve for longitudinal movement relative to said body, means for locking said valve in bore-closing position, comprising, keeper means supported on the body for movement relative to the valve between positions holding said valve in bore-closing position and releasing said valve for movement to the boreopening position, and means movably mounted on the body connected to the keeper means and operable in response to iluid pressure in said bore to move said keeper from the valve-releasing position to the valve-holding position.

2. In combination with a dapper-type valve including a tubular body having a through bore, a fiapper-type valve hingedly secured to one side of said body for swinging movement between positions opening and closing said bore, means carried by the body for supporting said valve for longitudinal movement relative to said body, means for locking said valve in bore-closing position, comprising, keeper means supported on the body for movement relative to the valve between positions holding said valve in bore-closing position and releasing said valve for moverrr ment to the bore-opening position, and means movably mounted on the body connected to the keeper means and operable in response to fluid pressure in said bore to move said keeper from the valve-releasing position to the valveholding position, said last-mentioned means comprising, a sleeve member slidably disposed about the body to denne an eXpansible pressure chamber, and port means providing liuid pressure communication between said bore and said chamber.

3. A two-way dapper-type valve, comprising, a tubular body connectible into a well pipe string and having a through bore, a dapper-type valve hingedly secured to one side of said body for swinging movement between positions opening and closing the lower end of said bore, means biasing said valve to the bore-closing position, fluidpressure-actuated keeper means supported on the body and longitudinally movable thereon between an elevated position holding said valve in bore-closing position and a lower position releasing said valve for movement to the bore-opening position, means communicating iiuid pressure from said bore to said keeper means, a tubular mandrel longitudinally extendable through said bore between an advanced position holding said valve in the bore-opening position and a retracted position releasing said valve for movement to the bore-closing position, and seal means carried by the mandrel to seal with the wall of said bore and movable with the mandrel relative to said uid pressure communicating means to control the same.

4. A two-way dapper-type valve, comprising, a tubular body connectible into a well pipe string and having a through bore, a dapper-type valve hingedly secured to one side of said body for swinging movement between positions opening and closing the lower end of said bore, means biasing said valve to the bore-closing position, keeper means supported on the body and longitudinally movable between an elevated position holding said valve in bore-closing position and a lowered position releasing said valve for movement to the bore-opening position, fluid pressure-actuated means on the body for moving said keeper means, said iluid pressure-actuated means having an effective area exposed to fluid pressure in the bore of the body tending to open said valve greater than that of said valve, port means communicating uid pressure from said bore to said huid-pressure means, a tubular mandrel longitudinally entendible through said bore between an advanced position holding said valve `in the bore-opening position and a retracted position releasing said valve for movement to the bore-closing position, and seal means carried by the mandrel to seal with the wall of said bore and movable therewith relative to said port means for controlling lluid pressure communication between said bore and support means.

5. A two-way fiapper-type valve, comprising, a tubular body connectible to a well pipe and having a through bore a dapper-type valve, longitudinally movable means mounted on the body hingedly supporting said valve at one side of said body for swinging movements between positions opening and closing the lower end of said bore, means biasing the valve to the bore-closing position, a sleeve member longitudinally slidably surrounding said body to define an expansible pressure chamber therebetween, the effective area of said chamber exposed to pressure tending to open said valve being greater than that 0f said valve, a keeper member carried by said sleeve member to extend beneath said valve, means for directing pressure fluid from said bore into said chamber to elevate said keeper member to a position holding said valve in the bore-closing position, and a tubular mandrel member extendible through said bore between an advanced position holding said valve in the bore-opening position and a retracted position releasing said valve for movement to the boreclosing position.

6. A two-way dapper-type valve, comprising a tubular body connectible to a well pipe and having a through bore, a dapper-type valve hingedly secured to one side of said body for swinging movements between positions opening and closing the lower end of said bore, means biasing the valve to the bore-closing position, a sleeve member longitudinally slidably surrounding said body to deiine an expansible pressure chamber therebetween, the eiective area of said chamber exposed to pressure tending to open said valve being greater than that of said valve, a keeper member carried by said sleeve member to extend laterally beneath said valve, port means for directing pressure iiuid from said bore into said cylinder to elevate said keeper member to a position holding said valve in the bore-closing position, a tubuiar mandrel meniber extendible through said bore between an advanced position holding said valve in the bore-opening position and a retracted position releasing said valve for movement to the bore-closing position, and upper and lower longitudinally spaced seal means carried by said mandrel and movable therewith relative to said port means for controlling Huid pressure communication between said bore and said chamber.

7. A two-way dapper-type valve according to claim 6 wherein the upper one of said seal means is mounted on the mandrel for limitinglongitudinal movement relative thereto. A A

8. A two-way dapper-type valve, comprising, a tubular body connectible into a well pipe string and having a through bore, a dapper-type valve, support means hingedly securing said valve to one side of said body for swinging movement between positions opening and ciosing the lower end of said bore, said support means comprising a stem member 'longitudinally slidable in the wall of the body, a hinge connection between the lower end of said stem member and said valve, and means biasing said stem upwardly relative to the body, means biasing said valve to the bore-closing position, uid pressure-actuated keeper means supported on the body beneath said valve and longitudinally movable on the body between an elevated position holding said valve in bore-closing position and a lowered position releasing said valve for movement to the bore-opening position, means for directing actuating fluid pressure from said bore to said keeper means, and a tubular mandrel longitudinally extendible through said bore between an advanced position holding said valve in the bore-opening position and a retracted position releasing said valve for movement to the bore-closing position.

9. A two-way fiapper-type valve, comprising, a tubular body connectible into a Well pipe string and having a through bore, a iiapper-type valve, support means hingedly securing said valve to one side of said body for swinging movement between positions opening and closing the lower end of said bore, said support means comprising a stem member longitudinally slidable in the wall of the body, a hinge connection between the lower end of said stem member and said valve, and Vmeans biasing said stem member upwardly relative to the body, means biasing said valve to the bore-closing position, iiuid pressure-actuated keeper means supported on the body beneath said valve and longitudinally movable on the body between an elevated position holding said valve in bore-closing position and a lowered position releasing said valve for movement to the bore-opening position, port means ycommunicating actuating iiuid pressure from said bore to said keeper means, a tubular mandrel longitudinally extendible through said bore between an advanced position holding said valve in the bore-opening position and a retracted position releasing said valve for movement to the boreclosing position, and upper and lower longitudinally spaced seal means carried by said mandrel and movable therewith relative to the port means for controlling iiuid pressure communication between said bore and said chamber.

10. A two-way dapper-type valve according to claim 9 wherein said upper one of said seal means is mounted in the mandrel for limited longitudinal movement relative thereto.

11. A two-way dapper-type valve, comprising, a tubular body connectible into a well pipe string and having a through bore, a dapper-type valve, support means hingedly securing said valve to one side of said body for swinging movement between positions opening and closing the lower end of said bore, said support means .comprising a stem member longitudinally slidable in the wall of the body, a hinge connection between the lower end of said stem member and said valve, means biasing said stem member upwardly relative to the body, and means biasing said valve to the bore-closing position, keeper means supported on the body to extend beneath said valve and longitudinally movable on the body between an elevated position holding said valve in bore-closing position and a lowered position releasing said valve for movement to the boreopening position, fluid pressure-actuated means supported on the body and connected to the keeper means for moving said keeper means, said iiuid pressure-actuated means having an effective area exposed to uid pressure in the bore of said body tending to open said valve greater than that of said valve, port means communicating iiuid pressure from said bore to said uid pressure-actuated means, and a tubular mandrel longitudinally extendible through said bore between an advanced position holding said vaive in the bore-opening position and a retracted position releasing said valve for movement to the bore-closing position.

12. A two-way dapper-type valve according to claim 11 wherein said iiuid pressure-actuated means comprises a sleeve member longitudinally slidably surrounding said body to define an expansible pressure chamber having communication with said port means.

13. A two-way dapper-type valve, comprising, a tubular body connectible into a well pipe string fand having a through bore, a dapper-type valve, support means hingedly securing said vaive to one side of said body for swinging movement between positions opening and closing the lower end ofsaid bore, said support means comprising a stem member longitudinally slidable in the wall of the body, a hinge connection between the lower end of said stem member and said valve, means biasing said stem member upwardly relative to the body, means biasing said valve to the bore-closing position, keeper means supported on the body to extend laterally beneath said valve and longitudinally movable on the body between an elevated position holding said valve in bore-closing position and a lowered position releasing said valve for movement to the bore-opening position, iiuid pressure actuated means supported on the body and connected to the keeper means for moving said keeper means, said uid pressure-actuated means having an effective area exposed to fluid pressure in the bore of said body tending to open said valve greater than that of said valve, port means communicating iiuid pressure from said bore to said fluid pressure-actuated means, a tubular mandrel longitudinally extendible through said bore between an advanced position holding said Valve in the bore-opening position and a retracted position releasing said valve for movement to the boreclosing position, and longitudinally spaced seal means carried by said mandrel and movable therewith relative to the port means for controlling fluid pressure communication between said bore and said chamber.

References Cited in the tile of this patent UNITED STATES PATENTS 1,818,508 Scott Aug. 11, 1931 2,912,216 Conrad Nov. 10, 1959 2,921,601 Fisher Jan. 19, 1960

Claims

1. IN COMBINATION WITH A TUBULAR BODY HAVING A THROUGH BORE, AND A FLAPPER TYPE VALVE HINGEDLY SECURED TO ONE SIDE OF SAID BODY FOR SWINGING MOVEMENT BETWEEN POSITIONS OPENING AND CLOSING SAID BORE, MEANS CARRIED BY THE BODY FOR SUPPORTING SAID VALVE FOR LONGITUDINAL MOVEMENT RELATIVE TO SAID BODY, MEANS FOR LOCKING SAID VALVE IN BORE-CLOSING POSITION, COMPRISING, KEEPER MEANS SUPPORTED ON THE BODY FOR MOVEMENT RELATIVE TO THE VALVE BETWEEN POSITIONS HOLDING SAID VALVE IN BORE-CLOSING POSITION AND RELEASING SAID VALVE FOR MOVEMENT TO THE BOREOPENING POSITION, AND MEANS MOVABLY MOUNTED ON THE BODY CONNECTED TO THE KEEPER MEANS AND OPERABLE IN RESPONSE TO FLUID PRESSURE IN SAID BORE TO MOVE SAID KEEPER FROM THE VALVE-RELEASING POSITION TO THE VALVE-HOLDING POSITION.