US2855172A

US2855172A - Blowout preventer and ram therefor

Info

Publication number: US2855172A
Application number: US576637A
Authority: US
Inventors: Marvin R Jones
Original assignee: Cameron Iron Works Inc
Current assignee: Cooper Industries LLC
Priority date: 1956-04-06
Filing date: 1956-04-06
Publication date: 1958-10-07
Anticipated expiration: 1975-10-07

Description

Oct. 7, 1958 M. R. JONES 2,355,172

BLOWOUT PREVENTER AND RAM THEREFOR Filed April 6, 1956 3 Sheets-She et 1 uuuuumyun IN V EN TOR.

Oct. 7, 1958 M; R. JONES 2,855,172

BLOWOUT PREVENTER' AND RAM THEREFOR Filed April 6, 1956 s Sheets-Sheet 2 IN V EN TOR.

Oct. 7, 1958 I M. R. JONES 2,855,172

BLOWOUT PREVENTER AND RAM THEREFOR Filed April 6, 1956 S'Sheets-Sheet 3 w 0 If r 6? Q -l- United States Patent BLOWOUT PREVENTER AND RAM THEREFOR Marvin R. Jones, Houston, Tex., assignor to Cameron i ron Works, Inc., Houston, Tex., a corporation of exas Application April 6, 1956, Serial No. 576,637

31 Claims. (Cl. 251-2) This invention relates to control of well pressure while a well is being drilled, and more particularly to a blowout preventer which will seal in the well with the blowout preventer bore empty as Well as when a length of tubing, of drill pipe, of drill collar, of casing, or the kelly of a drilling string is in the bore without storage of excessive strain energy in the ram.

In drilling deep wells into high pressure formations, blowout preventers are used to seal in the well when emergency pressure conditions arise. The blowout preventers are made up as a part of the wellhead equipment and while hole is being made, a non-circular kelly through which rotation is imparted to the drill string extends through the blowout preventer. Thus, to close in a well with blowout preventers having ram fronts contoured to seal about a drill pipe or other circular cross-sectioned element of one specific diameter requires that the drill string be-lifted until the circular drill pipe portion of the drill string is within the blowout preventer before the blowout preventer rams are closed about the drill string.

Blowout preventers have been proposed which will seal about both the circular drill pipe portion of the drill string and about the non-circular kelly as well as close in an open bore. The sealing material of these blowout preventers has been formed in one or two masses Which requires tremendous deformation of the packing to give conformation and sealing pressure between the packing and drill string or to close the open here. See, for instance, Allen Patent Number 2,194,258 and Knox Patent Number 2,609,836.

Excessive deformation of the packing material shortens the life of the packing and necessitates the use of high powered motor operators for the blowout preventer. It is an object of this invention to provide a blowout preventer which will seal across an open bore or about an object in the bore with only a minimum of deformation of the packing material.

It is another object of this invention to provide a blowout preventer of this general type having rams which will conform to the contour of the front of another ram or to an object in the preventer without the necessity of deforming the packing material thereof.

It is still another object of this invention to provide a blowout preventer which will seal in a well whether the kelly or drill pipe portion of the drill string be in the blowout preventer bore or whether the blowout preventer bore be empty without storing excessive strain en ergy in the ram packing.

Another object is to provide a universal ram construction which will seal in a well whether the kelly or drill pipe portion of the drill string be in the blowout preventer bore or whether the bore be empty without requiring large amounts of strain energy to be stored in the ram packing, while keeping the distance to be bridged by resilient material small.

Another object is to provide a blowout preventer and universal ram therefor made up of a plurality of ram 2,855,172 Patented Oct. 7, 1958 closing force on the ram substantially uniformly to the several segments while permitting them to move relative to each other to provide a ram front of variable contour.

Another object is to provide a blowout preventer and rams therefor in which each ram is made up of several ram segments which are moved into engagement with another ram or with an object in the blowout preventer bore under substantially uniform pressure while being permitted to move relative to each other. to seal between rams or to assume the contour of and seal about an object in the bore, by hydraulic means for distributing pressure due to the closing force substantially uniformly to the several ram segments.

Another object is to provide a blowout preventer and rams therefor in which ram front packing is provided by several ram segments which are moved into engage ment with segments of another ram or with an object in the blowout preventer bore under substantially uniform pressure while being permitted to move relative to each other to seal between rams or to assume the contour of and seal about an object in the bore, by hydraulic means for distributing pressure due to the closing force substantially uniformly to the several ram segments.

Other objects, features and advantages of this invention will be apparent from the specification, drawings, and claims. V

In the drawings wherein there is shownseveral illustrative embodiments of this invention and wherein like reference numerals indicate like parts? Fig. 1 is a view partly in elevation and partly in vertical cross section of a blowout preventer embodying this invention;

Fig. 2 is a view in vertical section through a ram of the blowout preventer of Fig. 1 on an enlarged scale with one of the ram segments of the ram shown in elevation;

Fig. 3 is a fragmentary horizontal section through the ram of the blowout preventertaken along the lines of Fig. 2 and showing the ram in sealing engagement with a pipe in the blowout preventer bore;

Fig. 4 is a perspective view of one of the ram segments employed in the ram of Figs. 1 through 3 with a portion of the ram packing shown in phantom to illustrate details of the ram.

Fig. 5 is a fragmentary view in horizontal cross section through a blowout preventer with a kelly in the blowout preventer bore illustrating the manner in which the rams seal about a non-circular object in the bore;

Fig. 6 is a view similar to Fig. 5 illustrating the position of the several ram segments when the ram is retracted to clear the blowout preventer bore and with a portion of the top cover of the pressure distributing enclosure removed to illustrate details of constructio-n;

Fig. 7 is a fragmentary top view partially in plan and partially in horizontal cross section of a modified'form of this invention;

Fig. 7A is a fragmentary view in vertical section taken along the lines 7A7A-of Fig. 7;

Fig- 8 is a fragmentary vertical section through a'bl owout preventer showing a still further modified form of this invention;

Fig. 9 is a view in horizontal cross section of a fragment of a ram similar to the ram of Fig. 8;

Fig. 10 is a side elevational view of the ram of Fig. 9 taken along the lines 1(l10 of Fig.9; and

Fig. 11 is a top view of a ram of the form shown in Fig. 8 or Figs. 9 and 10 which the ram sealing about a pipe in the blowout preventer bore.

This invention may be practiced with a more or less conventional blowout preventer body such as indicated generally at in Fig; 1. Power for reciprocating the blowout reventer rams may be" provided in any conventional manner such as the hand wheel shown in' phantom at 11. With this form of applying power to the rams, the power shaft 12 is journaled in housing 13 by a'bearing'14 which is' held against reciprocation by a retaining wash'ei 15. The shaft 12' threadedly engages the ram' indicated generally at 16 as shown at 17.

The ram 16 is characterized by the employment of ram' s'e'gments'iridicated generally at'18 which are movable longitudinally relative to each other. The pressure due to the closing force applied to the ram is uniformly distributed to the several ram segments while permitting them to move longitudinally relative to each other by a coupling between the ram segments and the means of applying power. The coupling may be a liquid coupling or a mechanical couplingwhich functions in a hydraulic manner to permit the ram segments to assume differing positions as the ram segments move out in different amount and which will apply the pressure due to the closing'force substantially uniformly to each of the rams. Examples will be given herein of both a liquid and a mechanical hydraulic force transmitting means.

Referring more in particular to the details of the ram illustrated in Figs. 1 through 6-, it will be noted that'the power shaft 12 is connected to a carrier 20 which is mounted for reciprocation toward and away from the central bore 19 of' the blowout preventer in radially extending bores 21'. The front end of carrier 20 is provided with a shelf 22 on which the ram segments 18 rest and are free to slide longitudinally. To the rear of shelf 22 the carrier 20 is provided with a fluid hydraulic coupling indicated generally at 23.

Coupling 23, best shown in Figs. 2 3 and 6, employs two enclosures 24 and 25 each preferably substantially filled with a substantially incompressible liquid. The enclosures include a plurality of cylinders 26 in which there are slidingly received pistons 27. Each piston is provided with one or more O-rings 28 to form a sliding seal between the piston and wall of cylinder 26. Pistons 27 are the dividers between chambers 24 and 25 and as they reciprocate during movement of the ram the chambers are of varying shape. Connecting rods 29 extend from pistons 27 through wall 31 of enclosure 24 and are connected to the several ram segments as by the threaded connection 32. O-rings 33 are carried in wall 31 and seal between the wall 31 and each of connecting rods 29.

The pressure distributing means constructed as explained above has ineffect a flexible wall between the two enclosures 24 and'25 in the form of pistons 27. This flexible wall is free to vary its contour as the ram segments engage an' object in the blowout preventer bore such as a drill string and/or another ram. As carrier 20 is recip'rocated by wheel 11, the ram segments move withthe carrier 20 so long as they are free to do so and the position of each segment will depend upon friction drag upon the several segments. Uponengagement of an object in the central bore 19 by one of the ram segments, the'resistance to further movement of the ram segments will cause rearward movement relative to carrier of the-piston 27 which is carried by this ram segment. If both enclosures 24 and 25 are constant volume chambers, relative rearward movement of one piston 27 will cause relative forward movement of one or more of the other pistons 27 to maintain the constant volume. Thus, as one segment engages a pipe or kelly in the bore, its forward movement will be arrested and further forward movement of carrier 20 will not only carry the other arm segments forward, but the displacement of fluid by the piston associated with the stationary ram segment will cau'seone or more of the other ram segments to be extended tomaintain the constant volume in the two pressure enclosures. This action will continue until all of theraih segments are in engagment with some object in the ram bore at which time continued forward movement of carrier 20 will increase the pressure on the several pistons 27 in substantially equal amounts to exert a substantially constant pressure on the ram segments and to form a seal between the ram segments and the object within the central bore 19.

In order to maintain the throw'of the ram 16 at a mimmum value, it is desired that the ram segments assume the contour of the'blowout preventer bore when the rams are retracted. For this purpose, a backstop 34' is provided having an abutment su'rface34a confronting the rear of rams 18 and formed on a radius which will provide a ram front concentric withthe blowout preventer borewith the segments clearing the bore. As the carrier 20 is retracted, segments 18 will successively engage stop 34 until the ram front is arranged in the contour of the blowout preventer bore.

The ram segments 18 form a seal with an object in the ram bore, with each other and with the roof of the ram bore 21 to completely seal in the well bore. The body of each ram segment 18 is provided by a rigid member 35 which carries seal material at the nose and at least one side of the segment as well as at the top of the segment at' a point removed from the nose. Preferably body 35 has two

side wall grooves

36 and 37 in the opposite sides of the body and a groove 38 in the nose of the body interconnecting the two side wall grooves. The bo'dy'is further grooved in its top wall at 39 at a point spaced from the nose of the segment with the groove 39 communicating with the

side wall grooves

36 and 37. A body of sealing material 41 is molded in

grooves

36, 37, 38 and 39 as a continuous member. The exterior face of the resilient member 41 is flush with the adjacent walls of the body at all points except at the nose of the ram segment where the seal material bulges as at 42 to provide seal material for engagement with an object in the blowout preventer bore. The seal material 41 may be formed from any conventional ram packing material, such as rubber, synthetic rubber, etc.

The several ram segments 18 are arranged in sideby-side relationship on the shelf 22 of carrier 20 and have a few thousandths clearance with each other to permit them to move longitudinally on shelf 22 relative to each other. As they move into engagement with an object in the central bore, the bulge 42 at the nose of each ram segment will engage such object and arrest movement of the ram segment. As the ram segments are free to move relative to each other, there will not be a great amount of pressure placed on bulge 42 until each of the ram segments of a ram have come into abutment with an object in the central bore 19. At this time resistance to movement of all of the rams is present and further movement of the carrier 20 toward the central bore causes compression of bulge 42 which causes the seal material to flow back along

grooves

36 and 37 until the seal material in the

side grooves

36 and 37 bulges and increases the width of the segment to a point where the seal material 41 of adjacent segments is in engagement and seals between the several segments. The seal material will also flow to pressurize the seal material in groove 39 so that this portion of the seal material will seal with the roof of lateral bore 21. The seal between the seal material of adjacent segments will be continuous so that a continuous seal is formed across the roof of the bore 21 to the side walls of the bore 21 to prevent fluid from passing around or over the segments 18. The seal material in bulge 42 will seal about the object in the central bore as shown in Fig. 5 to'prevent fluid passing between such object and the ram front.

The ram segments 18 are held between the shelf 22 of carrier 20 and the top of ram bore 21 so that they may project into the central bore 19 and be supported in cantilever manner to provide a weir for containing the seal material 41 and preventing it from being excessively extruded under pressure of well fluid,

An alternate means of providing a ram front concentrio with the blowout preventer bore is provided by a resilient spring interconnecting the several ram segments as shown in Fig. 6. The top surface of body 35 has a double flaring notch 43 and aspring 44 is positioned in the several notches 43 of the segments 18. The notches are flared to permit the spring to bend and conform to the position of the several segments. The spring when in an unstressed position is bowed so as to return each of the ram segments to the position shown in Fig. 6. 7

Referring to Fig. 7, there is shown a modified form of this invention in which the enclosures for the means for distributing the pressure are stationary and the several pistons of the ram segments are reciprocated by applying fluid under pressure directly to the pistons.

- The ram segments 18 are identical with those of the previously described form of this invention. A carrier is not needed in this form of invention and the several segments may be dimensioned to extend from the top to the bottom of ram bore 21. Preferably, the ram bore will have a lesser vertical dimension so as to reduce the over-all height of the blowout preventer. The bonnet 47 for the ram bore 48 has formed therein a double enclosure coupling having a flexible wall to reciprocate ram segments 18. The coupling may be formed by a plurality of cylindrical bores 49 in bonnet 47, closed at each end, and interconnected at opposite ends by

passageways

51 and 52 respectively. Passageways 51 interconnect all of the cylinders at one end and an inlet 53 provides for movement of a fluid to and from the cylinders through passageways 51. Passageways 52 likewise connect all the cylinders at their other end and-a passageway 54 provides for introducing and removing a fluid from this end of the cylinder. Pistons 27 are mounted for reciprocation in the cylinders and are con nected to the ram segments by connecting rods 50 which extend through the inner wall of bonnet 47. An extension 55 on the rear of each piston is provided to abut the closures 56 for the cylinders and space the several ram segments to provide a ram frontin the general contour of the bore through the blowout preventer when they are in retracted position.

Conduits

53 and 54 are connected to a four-way valve 57 to which fluid under pressure'is supplied by pump 58. If desired, a reservoir 59 may be provided in series with the pump to receive fluid from the enclosure and feed it to pump 58. This form of blowout preventer is operated by manipulation of four-way valve 57 to introduce fluid to one side of pistons 27 and to exhaust fluid fromthe other side to reciprocate the ram segments. With the four-way valve positioned to supply pump pressure to the conduit 54, the pistons 27 will move toward the center of the blowout preventer and the ram segments 18 will seal with any object in the center of the bore. By maintaining the pressure against pistons 27 in any desired manner the rams will be held in their closed position. When it is desired to open the blowout preventer, the four-way valve 57 is reversed to exhaust pressure fluid from line 54 and to pressurize the other side of the pistons 27 through conduit 53 and move the segments rearwardly to the position shown in Fig. 7.

In Figs. 8 through 11, there are illustrated blowout preventers in which the ram segments are employed as ram front packing and cooperate with rear packing of a primary ram to complete the seal. There is also shown in these figures, a simple form of mechanical coupling.

The ram actuating rod 61 is mounted for rotation and reciprocation in yoke 62 and is packed as indicated at 63 to prevent leakage past the rod. The rod is provided with a head 64 which rotates in a slot 65 in the rear of primary ram 66. Slot 65 has overhanging flange portions 67 which prevent withdrawal of head 64 from the slot. Rotation of the rod 61 reciprocates the primary ram 66 within ram bore 68 inthe usual manner. The primary ram is provided with rear ram packing 69 which extends over the top of the primary ram and down each side of the primary ram to where it is engaged by the ram segments.

The ram front packing and pressure distributing means of this form of blowout preventer are carried in a key slot indicated generally at 71. The key slot extends horizontally from side to side of primary ram 66 and its narrow portion 72 opens into the nose of primary ram 66. The rearmost portion of key slot 71 is preferably substantially rectangular in section as shown at 73 and provides a space for the coupling. 7

The ram segments 74 are substantially identical with the ram segments of the other form of this invention except that they have formed at their rear end a vertical extending flange .75. This flange has a sliding fit with the wall of portions 73 of the key slot. The ram segments also have a sliding fit with the narrow portion 72 of the key slot and together with the side walls of the ram bore and the rectangular portion 73 of the key slot provide an enclosure for the coupling.

Substantially uniform pressure on the several ram segments 74 is provided by filling the portion 73 of the key slot not occupied by the ram segments with granular material such as steel balls which will roll over each other and permit the ram segments to move relative to each other while exerting a substantially uniform pressure on the segments. Preferably, there is provided an elastic flexible wall envelope 76 filled with steel balls 77 and extending completely across the primary ram 66 behind the flanges 75 of the several ram segments 74. A space is provided to the front of flanges 75 and above and below the segments 74 and these two spaces are also filled with flexible wall envelopes 78 likewise filled with balls 77.

In operation, the balls 77 act in a hydraulic manner to reciprocate the ram segments 74 as the primary ram 66 is reciprocated while permitting the several ram segments to move relative to each other as they engage an object in the blowout preventer bore. The flexible wall envelopes for balls 77 abut against side walls of ram bore 68 and the balls are held against sidewise extrusion by the ram bore.

A passageway 79 is provided at the bottom of the ram bore to permit well fluid to reach the rear of the ram and exert a forward pressure on the ram as will be understood by those skilled in the art. The juncture of the rear packing and the ram segment packing, however, contain this pressure and prevent it from passing through the blowout preventer.

Referring now to Figs. 9 and 10, there is shown a slightly modified form of ram utilizing ram front packing such as at Fig. 8 in which the

flexible wall envelopes

76 and 78 are omitted. In this form of ram the granular material 77 is contained by plates 80 which are secured over the openings formed in each side of primary ram 66 by the enlarged portion 73 of the key slot. Ram segment flanges 75a have a length dimension slightly greater than one half the width of portion 73 of the key slot so that adjacent flanges 75a will always be in contact with each other and prevent passage of granular material 77 thereby as the ram segments 74 move relative to each other. The side ram segments have a sliding fit with plate 89. The relationship of the diameter of the material and the clearances between the ram segments and the key slot is such that the granular material cannot pass through these clearances but will be contained in its own enclosure. This form of the invention does away with theneed for

flexible envelopes

76 and 78 and prevents any pressure exerted through the granular material from being applied to the side walls of the ram bore thus eliminating frictional drag which will be present in the Fig. 8 form of this invention.

From the above, it is believed clear that all of the objects of this invention have been attained. There has been provided a blowout preventer and ram therefor which will seal the open bore of the blowout preventer or will seal about either the tubing or kelly of a drill string without storing excessive strain energy. The power required for operation of the ram will thus be greatly reduced. The construction is such that the distance to be bridged by resilient material is held to a minimum. As a part of the universal rarn, there is provided a coupling for distributing the pressure due-to a closing force on the ram substantially uniformly across the ram front while permitting the ram front to assume a variable contour without the storage of excessive strain energy in the ram. This. coupling is hydraulic in nature and may be provided by a liquid means or a mechanical means.

As indicated in the drawings, the invention may be used to provide the entire ram or it may be used as ram front packing.

The liquid hydraulic form of the invention may be constructed with the coupling chamber rigidly secured to the blowout preventer body or provided as a part of and carried by the ram.

From the foregoing it will be seen that this invention is one well adapted to attain all of the ends and objects hereinabove set forth, together with other advantages which are obvious and which are inherent to the apparatus.

It will be understood that certain features and subcombinations are of utility and may be employed without reference to other features and subcombinations. This is contemplated by and its within the scope of the claims.

As many possible embodiments may be made of the invention without departing from the scope thereof, it is to be understood that all matter herein set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

I claim:

1. A blowout preventer comprising; a housing; a central bore through the housing to be closed; a plurality of transverse ram bores radiating from the central bore; a mm in each ram bore including a plurality of ram segments arranged side by side across the ram and individually reciprocable toward and away from the central bore; means sealing between the ram segments, and between the ram and ram bore, and between the ram segments and an object in the central bore when the segments are forced against said object to seal off the central bore, and sealing ram to ram when the central bore is empty and the rams are forced together; and means for reciprocating each ram segment including means for distributing pressure due to a closing force substantially uniformly to the ram segments while permitting them to move relative to each other and the ram fronts to abut when the central bore is empty or to assume the contour of an object in the central bore.

2. A blowout preventer comprising, a housing, a central bore through the housing to be closed, a plurality of transverse ram bores radiating from the central bore, a ram in each of said ram bores including a plurality of ram segments arranged side-by-side in the ram bore, each ram segment having a side wall and nose section of resilient sealing material which when stressed by being forced against another ram or an object in the central bore seals between adjacent rain segments, and means for reciprocating each ram segment including means for distributing pressure due to a closing force substantially uniformly to the ram segments while permitting them to move relative to each other and the ram fronts to abut when the central bore is empty or to assume the contour of an object in the central bore.

3. A blowout preventer comprising, a housing, a central bore through the housing to be closed, a plurality of transverse ram bores radiating from the central bore, a ram in each of said ram bores including a plurality of ram segments arranged side-by-side in the ram bore, each ram segment having a side wall and top wall and nose section of continuous resilient sealing material which when stressed by being forced against another ram or an object in the central bore seals between adjacent ram segments, the top seal sections of the several rams engaging and sealing with each other in any relative position of the segments in sealing the central bore and engaging a surface of the respective ram bore above the segments to form a seal therewith, and means for reciprocating each ram segment including means for distributing pressure due to a closing force substantially uniformly to the ram segments while permitting them to move relative to each other and the ram fronts to abut when the central bore is empty or to assume the contour of an object in the central bore.

4. A blowout preventer comprising, a housing, a central bore through the housing to be closed, a plurality of transverse ram bores radiating from the central bore, a ram in each of said ram bores including a plurality of ram segments arranged side-by-side in the ram bore, each ram segment comprising a rigid body having a groove in each side wall and a groove across the nose of the segment interconnecting the side wall grooves, sealing material in said grooves and projecting beyond the nose of the body which when stressed by coming into contact with another ram or with an object in the central bore bulges from the side wall groove to seal between adjacent ram segments, and means for reciprocating each ram segment including means for distributing pressure due to a closing force substantially uniformly to the ram segments while permitting them to move relative to each other and the ram fronts to abut when the central bore is empty or to assume the contour of an object in the central bore.

5. A blowout preventer comprising; a housing; a central bore through the housing to be closed; a plurality of transverse ram bores radiating from the central bore; a ram in each ram bore including a plurality of ram segments arranged side-by-side across the ram and individually reciprocable toward and away from the central bore; means sealing between the ram segments, and between the ram and ram bore, and between the ram segments and an object in the central bore when the segments are forced against said object to seal off the central bore, and sealing ram to ram when the central bore is empty and the rams are forced together; and means for reciprocating each ram segment including an enclosure, means filling said enclosure and movable within the enclosure under pressure without storing excessive strain energy to transmit a closing force to the ram segments while permitting them to move relative to each other and the ram fronts to abut when the central bore is empty or to assume the contour of an object in the central bore.

6. A blowout preventer comprising; a housingya central bore through the housing to be closed; a plurality of transverse ram bores radiating from the central bore; a ram in each ram bore including a plurality of ram segments arranged side-by-side across the ram and individually reciprocable toward and away from the central bore; means sealing between the ram segments, and between the ram and ram bore, and between the ram segments and an object in the central bore when the segments are forced against said object to seal off the central bore, and sealing ram to ram when the central bore is empty and the rams are forced together; means for reciprocating each ram segment including two enclosures each formed in part by a flexible wall provided by the ram segments; and means filling said enclosures and movable Within the enclosures under pressure without storing excessive strain energy to transmit a closing force to the ram segments While permitting them to move relative to each other and the ram fronts to abut when the central bore is empty or to assume the contour of an object in the central bore.

7. A blowout preventer comprising; a housing; a central bore through the housing to be closedya plurality of transverse ram bores radiating from the central bore; a ram in each ram bore including a plurality of ram segments arranged side-by-side across the ram and individually reciprocable toward and away from the central bore; means sealing between the ram segments, and between the ram and ram bore, and between the ram segments and an object in the central bore when the segments are forced against said object to seal off the central bore, and sealing ram to ram when the central bore is empty and the rams are forced together; and means for reciprocating each ram segment including a fluid enclosure, a plurality of cylinders in a wall of the enclosure, pistons reciprocably mounted in the cylinders and carried by the ram segments, and a liquid in said enclosure acting on the pistons and forcing the ram segments toward the central bore with an increase in fluid pressure, said liquid maintaining substantially equal pressure on each piston while permitting the rams to move relative to each other and the ram fronts to abut when the central bore is empty or to assume the contour of an object in the central bore.

8. The blowout preventer of claim 7 wherein the liquid is confined within the enclosure and the enclosure is movable in the ram bore to vary the pressure of the liquid.

9. The blowout preventer of claim 7 wherein the enclosure is fixed to the blowout preventer body and. the volume of the liquid in the enclosure is varied to reciprocate the ram segments.

10. A blowout preventer comprising; a housing; a central bore through the housing to be closed; a plurality of transverse ram bores radiating from the central bore; a ram in each bore including a primary ram having a sliding fit with the ram bore and reciprocable therein; a slot extending across the primary ram perpendicular to the central bore and opening into the nose of the primary ram; a plurality of ram segments arranged side-by-side in the slot and individually reciprocable toward and away from the central bore; means forming a continuous seal between the ram segments, between the ram segments and primary ram, between the primary ram and ram bore, and between the ram segments and an object in the central bore when the segments are forced against said object to seal off said central bore, and sealing ram to ram when the central bore is empty and the segments are forced together; and means in said slot for reciprocating each ram segment including an enclosure formed in part by a flexible wall provided by the ram segments, means filling said enclosure and movable within the enclosure under pressure without storing excessive strain energy to transmit a closing force to the ram segments while permitting them to move relative to each other and the ram fronts to abut when the central bore is empty or to assume the contour of an object in the central bore.

11. The blowout preventer of claim 10 wherein the slot is enlarged at its inner extremity, each ram segment has a flange part extending parallel to the axis of the central bore and in sliding engagement with the enlarged portion of the slot, said enclosure begins at the flange parts and extends toward the rear of the ram, and a second enclosure also formed in part by a flexible wall provided by the ram segments and filled with means movable under pressure without storing excessive strain energy begins at the flange parts and extends toward the front of the ram to transmit an opening force from the primary ram to the ram segments, the opposite sides of the flange parts forming the flexible walls provided by the ram segments.

12. A blowout preventer comprising; a housing; a central bore through the housing to be closed; a plurality of transverse ram bores radiating from the central bore; a ram in each ram bore including a plurality of ram segments arranged side-by-side across the ram and individually reciprocable toward and away from the central bore; means sealing between the ram segments, and between the ram and ram bore, and between the ram segments and an object in the central bore when the segments are forced against said object to seal off the central bore, and sealing rarn to ram when the central bore is empty and the rams are forced together; and means'for reciprocating each ram segment including means for distributing the pressure due to a closing force substantially uniformly to the ram segments while permitting them to move relative to each other and the ram fronts to abut when the central bore is empty or to assume the contour of an object in the central bore; and means arranging the ram segments to conform to the central bore when the rams are retracted.

13. The blowout preventer of claim 12 wherein the conforming means is a backstop which engages the ram segments as the segments are retracted.

14. The blowout preventer of claim 12 wherein the conforming means is a resilient means attached to each ram segment.

15. A ram for a blowout preventer comprising, a plu- 'rality of ram segments arranged side-by-side and having a side wall and nose section of resilient sealing material for sealing between adjacent ram segments, and means carried by the ram for distributing the pressure due to a closing force on the ram substantially uniformly between the ram segments while permitting them to move relative to-each other to provide differing contours of ram front.

16. A ram for a blowout preventer comprising, a plurality of ram segments arranged side-by-side and having a side wall, top wall and nose section of continuous resilient sealing material for sealing between adjacent ram segments, and means carried by the ram for distributing the pressure due to a closing force on the ram substantially uniformly between the ram segments while permitting them to move relative to each other to provide difiering contours of ram front. 1

17. A ram for a blowout preventer comprising, a plurality of ram segments arranged side-by-side and having :a side wall, top wall and nose section of continuous re silient sealing material for sealing between adjacent ram segments, an enclosure carried by the ram and having at least one wall in force transmitting relationship with each segment, means filling said enclosure and movable therein under pressure without storing excessive strain energy to move the sections longitudinally while permitting the segments to move lengthwise relative to each other to provide differing contours of ram front.

18. A ram for a blowout preventer comprising, a plurality of ram segments arranged side-by-side and having a side wall, top wall and nose section of continuous .in a wall of the enclosure, pistons reciprocably mounted in the cylinders and carried by the ram segments, a

liquid in said enclosure acting on the pistons and reciprocating them with changes in fluid pressure, said liquid maintaining substantally equal pressure on each piston while permitting the segments to move relative to each other to provide differing contours of ram front.

19. A ram for a blowout preventer comprising, a primary ram adapted to be slidably mounted in a ram bore, a slot extending-across the primary ram and opening into its nose, a plurality of ram segments arranged side-by-side in the slot and extending from the nose of the ram and individually reciprocable in the slot, means, for forming a continuous seal between the ram segments, and between the ram segments and primary ram, said means also providing a ram front seal and a ram rear seal, and means in said slot for reciprocating each ram segment including an enclosure formed at least in part by a flexible wall provided by the ram segments, and means filling said enclosure and movable within the enclosure under pressure without storing excessive strain energy to reciprocate the ram segments while permitting them to move relative to each other.

20. A ram for a blowout preventer comprising, a

primary ram adapted to be slidably mounted in a ram bore, a slot extending across the primary ram and opening into its nose, a plurality of ram segments arranged side-by-side in the slot and extending from the nose of the ram and individually reciprocable in the slot, means for forming a continuous seal between the ram segments, and between the ram segments and primary ram, said means also providing a ramfront seal and a ram rear seal, and means in said slot for reciprocating each ram segment including a flexible wall envelope and means filling said envelope and movable within the envelope under pressure without storing excessive strain energy to reciprocate the ram segments while permitting them to move relative to each other.

21. A blowout preventer comprising; a housing; a cenbore through the housing; a plurality of ram bores intersecting the central bore; a ram in each ram bore for closing the central bore and including a plurality of ram segments arranged side by side across the ram and individually reciprocable toward and away from the central bore to permit the ram fronts to abut when the central bore is empty or to assume the contour of an object in the central bore; and means for sealing between the ram segments of each ram, between each ram and its bore, and between the ram segments and the object in the central bore or between rams when the central bore is empty. V

22. A blowout preventer comprising; a housing; a central bore through the housing; a plurality of ram bores intersecting the central bore; and a ram in each ram bore for closing the central bore and including a plurality of ram segments arranged side by side across the ram and individually reciprocable toward and away from the central bore to permit the ram fronts to abut when the central bore is empty or to assume the contour of an object in the central bore; each ram segment of each ram having a side wall and nose section of resilient sealing material which, when stressed by being forced against a ram segment of another ram or the object in the central bore, seals with adjacent ram segments.

23. A blowout preventer comprising; a housing; a central bore through the housing; a plurality of transverse ram bores intersecting the central bore; a ram in each ram bore including a plurality of ram segments arranged side by side across the ram and individually reciprocable toward and away from the central bore to permit the ram fronts to abut when the central bore is empty or to assume the contour of an object in the central bore; means for applying a closing force to the ram; flowable material enclosed between the ram segments and the force applying means to transmit pressure due to the closing force to the ram segments while permitting them to reciprocate relative to one another; and means for sealing between the ram segments of each ram, between each ram and its bore, and between the ram segments and the object in the central bore or between rams when the central bore is empty.

24. A ram for a blowout preventer comprising, a plurality of individually reciprocable ram segments arranged side by side across the ram, each ram segment having a nose section and side wall of resilient sealing material for sealing across the front of the ram and between adjacent ram segments.

25. A ram for a blowout preventer comprising, a plurality of individually reciprocable ram segments arranged side by side across the ram, each ram segment having a nose section, side wall and top wall of resilient sealing material for sealing across the front of the ram, between adjacent segments and across the top of the ram,

26. A ram for a blowoutpreventer comprising, a carrier and a plurality of individually reciprocable ram segments arranged side by side across the front of the carrier, and fiowable material enclosed between the carrier and ram segments to transmit a closing force to the ram segments while permitting them to reciprocate relative to one another, each ram segment having a nose section and side wall of resilient material for sealing across the front of the ram and between adjacent ram segments.

27. Valve apparatus comprising; a housing; a central bore through the housing; a bore intersecting the central bore; a closure member in the intersecting bore for closing the central bore and including a plurality of segments arranged side by side across the closure member and individually reciprocable toward and awayfrom the central bore to permit the front of the closure member to assume the contour of a surface which it engages within the central bore; and means for sealing between the segments, between the closure member and its bore, and between the segments and said surface in the central bore.

28. Valve apparatus comprising; a housing; a central bore through the housing; a bore intersecting the central bore; a closure member in the intersecting bore including a plurality of segments arranged side by side across the ram and individually reciprocable toward and away from the central bore to permit the front of the closure member to assume the contour of a surface which it engages within the central bore; means for applying a closing force to the ram; flowable material enclosed between the segments and the force applying means to transmit pressure due to the closing forceto the segments while permitting them to reciprocate relative to one another; and means for sealing. between the segments, between the closure member and its bore, and between the segments and said surface in the central bore.

29. A closure member for valve apparatus comprising, a plurality of individually reciprocable segments arranged side by side across the closure member, each segment having a nose section and side wall of resilient sealing material for sealing across the front of the closure member and between adjacent segments.

30. A closure member for valve apparatus comprising, a plurality of individually reciprocable segments arranged side by side across the closure member, each segment having a nose section, side wall and top wall of resilient sealing material for sealing across the front of the closure member, between adjacent segments and across the top of the closure member.

31. A closure member for valve apparatus comprising, a carrier and a plurality of individually reciprocable segments arranged side by side across the front of the carrier, and fiowable material enclosed between the carrier and segments to transmit a closing force to the segments while permitting them to reciprocate relative to one another, each segment having a nose section and side wall of resilient sealingmaterial for sealing across the front of the closure member and between adjacent segments.

References Cited in the file of this patent UNITED STATES PATENTS 1,586,923 Townsend June 1, 1926 1,966,809 Wickersham July 17, 1934 2,194,258 Allen Mar. 19, 1940 2,207,149 Hild July 9, 194-0 2,293,153 Lorehn Aug. 18, 1942 2,318,882 Nevill May 11, 1943 2,746,710 Jones May 22, 1956 2,749,078 Losey June 5, 1956