Title:
BLOWOUT PREVENTER
United States Patent 3647174


Abstract:
Blowout preventers of the ram-type, each having a bonnet which is detachably connected to the preventer body, and which bonnet is movable away from the preventer body to expose the ram therewith for permitting removal of the ram from the preventer for replacement or repair, wherein the ram piston and cylinder which are operable for moving the ram to and from its open and closed positions when the bonnet is secured to the preventer body are also operable for moving the bonnet away from and towards the preventer body when the bonnet is disconnected from the body. Detent means are provided for resisting relative movement between the ram and the body when the ram is in the open position and the bonnet is disconnected from the body, whereby the bonnet can be moved away from the body to the exposed ram position and then returned to reengage the bonnet with the body. Flexible hydraulic fluid conductor means is provided for operating the piston and for moving the cylinder relative to the piston.



Inventors:
LEROUAX ROBERT K
Application Number:
05/075360
Publication Date:
03/07/1972
Filing Date:
09/25/1970
Assignee:
HYDRIL CO.
Primary Class:
Other Classes:
91/217, 92/128, 251/31, 277/323, 277/325
International Classes:
E21B33/06; (IPC1-7): E21B29/00; F16K3/02
Field of Search:
251/1,146 166
View Patent Images:
US Patent References:
3561526PIPE SHEARING RAM ASSEMBLY FOR BLOWOUT PREVENTER1971-02-09Williams et al.
3554480BLOWOUT PREVENTER1971-01-12Rowe
3272222Blowout preventer1966-09-13Allen



Primary Examiner:
Nelson, Cary M.
Assistant Examiner:
Matthews, David R.
Claims:
I claim

1. A blowout preventer, comprising:

2. The structure set forth in claim 1, wherein:

3. The structure set forth in claim 1, wherein said resistance means includes:

4. The structure set forth in claim 3, wherein said detent means includes:

5. The structure set forth in claim 3, wherein:

6. The structure set forth in claim 5, wherein:

7. The structure set forth in claim 1, including:

8. The structure set forth in claim 7, wherein said stop means includes:

9. The structure set forth in claim 1, wherein said fluid pressure means includes:

10. The structure as set forth in claim 9, wherein at least one of said fluid conduits includes:

11. The structure set forth in claim 10, wherein said flexible conduit section comprises:

12. The structure set forth in claim 10, wherein said flexible conduit section comprises:

13. The structure set forth in claim 10, including:

14. A blowout preventer, comprising:

15. The structure set forth in claim 14, wherein said flexible conduit section comprises:

16. The structure set forth in claim 14, wherein said flexible conduit section comprises:

17. The structure set forth in claim 14, including:

18. A blowout preventer, comprising:

19. The structure set forth in claim 18, including:

20. The structure set forth in claim 18, wherein:

Description:
BACKGROUND OF THE INVENTION

The field of this invention is blowout preventers.

It often becomes necessary or desirable to replace the rams, or at least the sealing components thereof, in a blowout preventer while the preventer is in the field in its normally mounted position at a wellhead. In the past, various efforts have been made to facilitate such field removal of the rams for replacement and/or repair, examples of which are shown in U.S. Pats. Nos. 2,752,119; 2,912,214; and 3,272,222. In the blowout preventer constructions of such prior art, the rams were operated normally by the main hydraulic system, and a separate additional hydraulic system was required to move the blowout away from and back to the preventer body. Such prior art constructions required telescoping tubes for carrying the hydraulic fluid to effect the movements of the bonnet relative to the head, which tubes had to have polished or smooth external surfaces to maintain a fluid seal during the telescoping movements. Such smooth surfaces were always exposed to damage such as scratches, indentations and nicks caused by tools and parts hitting the tubes when the bonnet and ram were in the open exposed position. If the damage was severe enough, destruction of the seals soon followed, with consequent leaks of hydraulic fluid, and causing the equipment to malfunction or become inoperative.

Furthermore, because of the use of the supplemental hydraulic system for moving the bonnet in such prior art blowout preventers, the overall weight of the preventer was excessive, and the force exerted in closing the bonnet in sealing contact with the head was relatively small. Also, an excessively large number of fluid seals was required in such constructions. Additionally, the location of such telescoping tubes in the prior art blowout preventers interfered with and prevented lateral removal of the rams from the preventer, so that it was very difficult, and often impossible, to remove the rams from a lower preventer in a vertically stacked double preventer assembly without first extending the bonnet in the upper preventer and removing the upper rams therefrom.

SUMMARY OF THE INVENTION

A blowout preventer of the ram-type having piston and cylinder means for effecting normal opening and closing of the rams and for also effecting movements of the preventer bonnet away from and back to the preventer body when the bonnet is disconnected from the body, whereby increased power is available for opening and closing the bonnet, a lighter weight structure is possible and fewer seals are required, as compared to the prior art. Additionally, the telescoping tubes for the supplemental bonnet hydraulic system used in the prior art are not necessary with the present invention, thereby solving the problem of the failure of such prior art preventers when the telescoping tubes were damaged. Preferably, flexible hydraulic lines are utilized in the blowout preventers of this invention rather than telescoping tubes.

The blowout preventer of this invention is also constructed so that the rams can each be removed vertically or laterally from the preventer, whereby the rams in a lower preventer of a vertically stacked double preventer can be removed without opening the bonnets and removing the rams of the upper preventer, thereby saving man-hours and needless effort.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an elevation of the blowout preventer of this invention, illustrating the preventer with the left-hand bonnet in the ram-exposed position, and the right-hand bonnet in the normal connected position;

FIG. 2 is an end view of the blowout preventer of this invention;

FIGS. 3, 4, and 5 are cross-sectional views of the blowout preventer of FIG. 1, showing the left-hand portion thereof, with FIG. 3 illustrating the preventer in the normal operating position with the ram closed, FIG. 4 showing the preventer in the normally operating position with the ram in the open position; and FIG. 5 showing a view taken on line 5--5 of FIG. 1 to illustrate the bonnet in the open, ram-exposing position;

FIGS. 6A, 6B and 6C are vertical sectional views taken from the left hand to the right-hand end of the left-hand portion of the blowout preventer of this invention, illustrating in detail one of the rams with its associated structure;

FIG. 7 is a sectional view taken on line 7--7 of FIG. 6C;

FIG. 8 is an enlarged sectional view taken on line 8--8 of FIG. 4, illustrating in detail one form of the flexible fluid conduit which is preferably utilized with the blowout preventer of this invention;

FIG. 9 is an end view of a modified ram, with a portion of a piston rod detachably connected thereto, and illustrating in particular the construction of the ram to effect removal of the ram from the piston rod either vertically or laterally;

FIG. 10 is a cross-sectional view illustrating a modified form of the flexible fluid conduits which may be utilized in place of the flexible fluid conduit illustrated in FIG. 8 in particular;

FIG. 11 is an elevation, partly in section, illustrating further details of the modified flexible fluid conduits of FIG. 10; and

FIG. 12 is a view similar to FIG. 10, but illustrating the flexible conduits in their collapsed or smallest dimension position with the bonnet in contact with the preventer body so that the normal ram movements may be conducted.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the drawings, the letter A designates generally the blowout preventer of this which is connected in the usual way to well casing or pipe P, using bolts 10 which extend through a flange 11 on each section of the casing P into a body B of the preventer A. The body B is of conventional construction and includes a central longitudinal opening 12 therethrough which is aligned with the vertical opening through the casing or pipe P. The body B also has laterally disposed ram openings 14 which are disposed on diametrically opposite sides of the body B, extending entirely through the wall of such body B, and communicating with the longitudinal opening 12. A ram R of any suitable construction is mounted so that it is laterally movable in one of the lateral ram openings 14 and it has any suitable sealing assembly 15 formed of rubber or similar material therewith in the usual manner. The rams R are adapted to be moved laterally from the closed position (FIGS. 3 and 6C) in which position they close off fluid flow through the central opening 12, to an open position (FIG. 4) in normal operation, wherein the central bore 12 is open for performing normal well operations therethrough.

Furthermore, as will be explained more in detail, the blowout preventer A of this invention is constructed so that a bonnet H is mounted so as to enclose each of the rams R on each side of the blowout preventer body B. Each of the bonnets or heads H is releasably connected to the body B with bolts 18 or any other suitable releasable securing means in the known manner. An operating cylinder C is secured to the bonnet H by bolts 20 or other suitable securing means (FIG. 1) so that the cylinder C is movable with the bonnet H. A piston D is slidably positioned within the cylinder C (FIGS. 3, 4, 5 and 6B). Each piston D is connected to one of the rams R by a piston rod 22 so that movements of the piston D are transmitted to the ram R connected therewith. As will be more fully explained, fluid pressure is supplied to the cylinder C, preferably through fluid conduits F-1 and F-2 so as to move the piston D within the cylinder C for moving the ram R therewith to and from the closed and open positions. Also, when the bonnet H is disconnected from the body B, the fluid pressure in the cylinder C is utilized to move the cylinder C relative to the piston D (FIG. 5) for moving the bonnet H away from the preventer body B so as to expose the ram R for removal. The fluid pressure is also utilized for the return of the cylinder C relative to the piston D to return the bonnet H to the closed position (FIG. 4) for connecting same to the preventer body B for normal operations of the ram R. It will be understood that throughout this description, the structure and operation for only the left-hand ram R and the parts therewith are explained in detail, since the structure and operation of the other ram and parts therewith are generally the same.

Considering the invention more in detail, the left hand ram R (FIG. 1) is illustrated as having a generally oval shape, although it may be cylindrical or of any other suitable shape so as to properly function within its ram opening 14 in the body B. The ram R is releasably connected to the piston rod 22 by means of a rod connector pin 24 having an enlarged button 24a. The connector 24 may be integral with the rod 22, or it may be threaded thereto as indicated at 24b (FIG. 6C). An annular projection 24c is also formed with the connector 24 and is disposed in proximity to the end of the piston rod 22, for a purpose to be hereinafter explained. As best seen in FIG. 9, the ram R is formed with a laterally extending slot 25 and a vertically extending slot 26. The dimensions of the button connector 24a are larger than the diameter of the shaft portion of the connector 24 so that the button 24a fits within an enlarged channel 25a of the slot 25, or an enlarged channel 26a of the vertical slot 26. The diameter of the shaft portion of the connector 24 is slightly smaller than the width of the slot 25 or the slot 26. The ram R can thus be moved transversely relative to the connector 24 as the shaft portion of the connector 24 moves through the slot 25 and the button 24a moves through the enlarged channel portion 25a of the slot 25. Since the slot 25 and its channel 25a extend entirely across the ram R, the ram R may be removed from the connector 24 and thus from the piston rod 22 in either lateral direction. Similarly, the ram R may be removed by raising it vertically so that the shaft portion of the connector 24 passes through the slot 26 and the button 24a passes through the channel portion 26a of the slot 26. To facilitate the positioning of the ram R at the proper central position with respect to the connector 24, a recess 25b is formed in the upper wall of the slot 25 to receive a part of the connector 24 (FIG. 9) when the connector 24 is in the proper position at approximately the midpoint of the ram R. In FIG. 9, the connector button 24a and a portion of the shaft of the connector 24 are illustrated in dotted lines to show the position thereof during the removal of the ram R transversely, using the slot 25.

In the preferred form of the invention illustrated in FIGS. 6A-6C, the body B has an extension 30 which is welded or is otherwise secured to the body B, and which includes an upstanding resistance member 31 having an annular recess 31a therein, which forms a part of a detent means for resisting movement of the ram R relative to the body B when the bonnet H is disconnected from the body B, as will be more fully explained. The other part of the detent means or resistance means is a flexible split ring 32 (FIGS. 6C and 7) which is mounted at the end of the rod 22 near the ram R.

The ring 32 is split as indicated at 32a (FIG. 7) so that is can contract in its external diameter to enter the recess 31a. Its inherent resiliency normally urges it to a diameter which is greater than the diameter of the rod 22 so that when the ring 32 is in the recess 31a, it resists movement of the rod 22 relative to the sleeve 31 and thus relative to the body B. The resilient ring 32 fits within an annular groove 22a having a plurality of stops 22b therein. However, it should be understood that any other suitable arrangement for providing a resiliently contractable and expansible member to enter the recess 31a to serve as the detent means or resistance means may be utilized. It should also be noted that the body extension 30 may serve as a shelf or additional support for the ram R when it is in the exposed position, although such additional support from the extension 30 is not necessary since the bonnet H and the parts therewith including the ram R are adequately supported by a pair of support tubes 35 when the bonnet H is in the open ram-exposing position (FIG. 5). It should also be pointed out that the support tubes 35 are located at the lower end of the body B so that the upper surfaces of such support tubes 35 are substantially at or are lower than the lower part of the ram R so that the ram R may be removed laterally from the rod 22 (FIG. 1).

Any suitable seal is provided between the bonnet H and the rod 22 to prevent the well fluid from entering the operating cylinder C, one form of which is illustrated in FIG. 6B and includes an annular lip type seal ring 36 formed of rubber or similar material which normally holds the well pressure. A secondary seal 37 of conventional construction which is energized by the injection of plastic backs up the lip seal 36. A third seal is provided by an O-ring 38. A weep hole 39 which has a hole 39a in communication therewith is provided to the atmosphere between the secondary seal and the O-ring 38 to make certain that there is no communication between the well fluid and the operating cylinder C.

A cylinder liner 40 is mounted on the bonnet H to provide a smooth internal cylindrical surface 40a in which the piston D may slide during relative reciprocatory movement of the piston D and the cylinder C. The external surface 40b of the cylinder liner 40 has a diameter which is less than the internal diameter of the main portion of the cylinder C so as to provide an inlet passage 41 which communicates with the interior of the cylinder liner 40 at the outer end 40c. Thus, when it is desired to introduce fluid under pressure into the cylinder C outwardly of the piston D, the fluid under pressure is introduced through the fluid conduit F-2 as will be more fully explained, from a source of the fluid pressure (not shown), whereby the fluid under pressure is introduced through the passage 41 at the end 40c of the cylinder 40.

When it is desired to introduce fluid under pressure into the cylinder C inwardly of the piston D, the fluid conduit F-1 is utilized.

Considering the fluid conduits F-1 and F-2 more specifically, reference is made to FIGS. 3-5 and 8 for details of one form of such conduit construction. Fluid under pressure is introduced into the body B through an inlet passage 50 which communicates with a flexible coiled hose 51, having one end 51a attached to the body B, and having the other end 51b thereof attached to the head or bonnet H. In the preferred form of the invention, the flexible conduit section of hose 51 is formed of rubber or any other suitable material which is capable of being expanded or extended from a retracted position (FIGS. 3 and 4) to an expanded position (FIG. 5). The fluid conduit section 51 fits within one of the support tubes 35 which serves as a protector for the hose 51 when the bonnet H is in the ram-exposing position (FIG. 5).

The bonnet H has a passage 52 which leads from the end 51b of the hose 51 to the cylinder C inwardly of the piston D so that whether the hose or conduit section 51 is in the extended position of FIG. 5, or in the retracted position of FIG. 8, the fluid may flow under pressure from the passage 50 through the conduit section 51 and the passage 52 into the cylinder C.

The fluid conduit F-2 is constructed in an identical manner to the fluid conduit F-1, except that the hose or fluid conduit section 51 of the conduit F-2 connects with a passage 53 in the bonnet H which establishes communication with the passage 41 in the cylinder C so as to direct the fluid under pressure to the area of the cylinder C outwardly of the piston D. Otherwise, the parts which are the same in the two fluid conduit systems F-1 and F-2 have like numerals and other designations. The details of the flexible hose or conduit section 51 which are illustrated in FIG. 8 have been specifically taken from line 8-8 of FIG. 4, but it will be understood that such details are likewise applicable to the flexible hose or conduit section 51 of the fluid conduit F-2, substituting the passage 53 for the passage 52 shown in FIG. 8.

For locking the ram R in the closed position (FIG. 3), a locking assembly is provided, the details of which are shown in FIGS. 6A and 6B. The locking assembly includes a locking sleeve 60 which has a nut section 60a welded or otherwise secured thereto, with internal threads 60b in threaded engagement with external threads 61a on a lock screw rod 61. A vent hole 61b is provided in the lock screw rod 61 for the release of fluid which is trapped when the lock sleeve 60 is unthreaded to the locked position. Under normal operating conditions with the head or bonnet H secured to the body B, the lock sleeve 60 and the lock screw rod 61 are in the telescoped or closed position illustrated in FIG. 6A and 6B and they more together with the piston D. The sleeve 60 moves through any suitable seals 62 (the outer one of which is a wiper) in the operating cylinder C, and the outer end of the sleeve 60 has a solid cap 60c which is welded or is otherwise affixed thereto beyond the extremity of the lock screw rod 61. Such cap 60c preferably has a square cross section so as to form wrench flats on its external surface to facilitate the rotation of the sleeve 60 and its threaded section 60a relative to the lock screw 61, as will be more fully explained. A protector tube 63 is welded or is otherwise affixed to the operating cylinder C for receiving the sleeve 60 to protect same against damage when the sleeve 60 is in the extended position.

The lock sleeve 60 preferably is provided with an antifriction stop ring or washer 60d (FIG. 6B) which is loosely positioned on the lock sleeve section 60 to form an annular surface which provides antifriction and prevents galling by contacting a machined surface 64 on the inside wall at the outer end of the operating cylinder C when the maximum extend of outward movement of the sleeve 60 relative to the cylinder C has been reached. Thus, when the piston D is in the inner position, with the ram R in the closed position (FIG. 3), the cap 60c may be rotated, using a wrench or any other suitable tool. The rotation of the sleeve 60 causes it to unthread relative to the lock screw rod 61, since the rod 61 is integral with, or connected with the rod 22 which is prevented from rotating due to the square or rectangular shape of the connector button 24a and the oval shape of the ram R. It will be appreciated that any other suitable means for preventing the rotation of the lock screw 61 may be provided so as to obtain the relative longitudinal unthreading of the sleeve 60. The sleeve 60 is unthreaded until the stop ring 60d engages the annular seating surface 64, at which point the piston D is prevented from moving outwardly from its inner position. It is to be noted that the protector sleeve 63 is omitted from FIGS. 1-5 for purposes of illustration, but it is shown in FIG. 6A in its preferred embodiment. Such sleeve 63 protects the sleeve 60 when it is in the extended position.

In the operation or use of the apparatus of this invention, the bonnet or head H is normally secured to the body B by means of the connecting bolts 18 or other suitable attaching means. Therefore, for normal operation of each ram R, fluid under pressure is introduced into the cylinder C outwardly of the piston D for moving the ram R inwardly to completely close the longitudinal central opening 12 in the body B. It will be understood that when the ram R is a "blind" ram, it engages a ram of the same configuration in the diametrically opposite position for completing the closure of the opening 12, as will be well understood by those skilled in the art. If the ram R is shaped for fitting around the external surface of a well pipe in the bore or opening 12, then the two opposed rams will close off the opening 12 around such pipe, as will be understood by those skilled in the art.

When it is desired to move each of the rams R to the open position so as to leave the bore or opening 12 completely open, fluid under pressure is introduced through the fluid conduit F-1 into the cylinder C inwardly of the piston D to thereby move the piston D outwardly to the position shown in FIG. 4 wherein the ram R is displaced outwardly with its innermost edge beyond the edge of the body B.

Under normal operations, the bonnet H thus remains connected to the body B, and the ram R on each side of the body B is moved back and forth as desired for controlling the opening and closing of the central or longitudinal opening 12 through the body B. The piston D and, therefore, the ram R on each side of the body B may be locked in the closed position by the unthreading of the lock sleeve 60 relative to the threaded lock screw rod 61, as previously explained.

When it is desired to move the ram R to the exposed position (FIG. 5) for the removal of the ram R from the preventer A, the ram R is first moved to the open position illustrated in FIG. 4, forcing the resilient ring 32 to enter the detent recess 31a (FIG. 4). In that position, the ram R is displaced outwardly of the body B. Thereafter, the bolts 18 or other suitable connecting means between the bonnet H and the body B are disconnected, and fluid under pressure is supplied through the fluid conduit F-2, including the flexible conduit section 51 to the cylinder C outwardly of the piston D. Since the resistance provided by the ring 32 in the detent recess 31a is greater than the frictional resistance between the bonnet H and the tubes 35, such fluid pressure acts to move the cylinder C outwardly while the piston D remains stationary. Since the operating cylinder C and the bonnet H are connected together by the bolts 20 or other suitable connecting means, the outward movement of the operating cylinder C moves the bonnet H outwardly therewith so as to fully expose the ram R (FIG. 5). It is to be noted that the flexible hoses or conduit sections 51 in the two fluid conduits F-1 and F-2 are fully protected by the support tubes 35 when the ram R is exposed for removal. The bonnet H and parts therewith are supported by the support tube 35. If desired, supplemental support may be provided for the ram R by resting same on the body extension 30, as previously explained.

When the ram R is in the ram-exposed position (FIG. 5), it may be removed either laterally in either direction or vertically, as previously explained. Since the ram R may be removed laterally, it is possible to remove the ram R even though it is the lower ram in a double blowout preventer with a pair of preventers in a vertical stack, without removing the upper ram in the stack, as is required in the prior art.

To return the bonnet H to the closed position (FIG. 4), fluid under pressure is introduced through the fluid conduit F-1 so that such fluid enters the operating cylinder C inwardly of the piston D. Outward movement of the piston D is prevented by the engagement of the projection 24c with the sleeve 31 so that the fluid under pressure inwardly of the piston D forces the cylinder C and bonnet H inwardly from the outer open position (FIG. 5) to the inner closed position (FIG. 4). The bolts 18 or other suitable connecting means are then reattached to secure the bonnet or head H to the body B so that normal ram operations may thereafter be continued.

It should be noted that instead of using the shoulder 24c for engagement with the sleeve 31, when returning the bonnet H to the closed position, the ram R itself may engage the sleeve 31 to resist outward movement of the piston D.

FIGS. 10-12 illustrate a modified form of the blowout preventer of this invention, with the body B-1, ram R-1, bonnet H-1, and cylinder C-1, corresponding to the body B, ram R, bonnet H and the operating cylinder C of FIGS. 1-9, but with certain modifications as will be explained. The fluid conduit system F-1 and F-2 illustrated in FIGS. 10-12 may be essentially identical with those heretofore described in connection with FIGS. 3-5 and 8, except that the flexible conduit section 51 of such figures is replaced by a hinged flexible conduit section 70. Each of the flexible hinged conduit sections 70 has pivoted connections 70a and 70b, with a hinge or pivot connection 70c joining rigid tubes 70d and 70e. The flexible conduit section 70 communicates with a fluid passage 150 in the body B-1 through which fluid under pressure is supplied from a source (not shown). The fluid conduit section 70 also communicates with a passage 152 in the bonnet H-1 which corresponds with the passage 52 in the bonnet H for supplying fluid under pressure to the operating cylinder C-1 inwardly of a piston D in the same manner as heretofore described in connection with FIGS. 1-9.

Support members 135 having a substantially "U" shape are connected to the body B-1 and extend over the top of each of the sections 70 to protect same when the bonnet H-1 is in the open ram-exposing position (FIG. 10). The bonnet H-1 has a suitable slot or recess 75 formed therein for each of the support members 135 to thereby permit movement of such support members 135 with respect to the bonnet H-1 when the bonnet H-1 is in the closed position (FIG. 12). The upper surface of each support member 135 is disposed substantially at or below the lower part of the ram R-1 (FIG. 11) to facilitate the removal of the ram R-1 laterally in either direction if desired. Also, the body B-1 has a recess 76 for each of the hinge sections 70, and the bonnet H-1 has a recess 77 for each of the hinge sections 70 so as to permit a collapse or contraction of each of the hinge sections 70 to its smallest dimension when the bonnet H-1 is in contact with the body B-1 (FIG. 12). It is to be noted that the support members 135 perform the same function as the tubes 35 in FIG. 5, in that such support members 135 support the bonnet H-1 and the parts therewith when the bonnet H-1 is in the open ram-exposing position (FIG. 10).

Although the resistance means or detent means provided by the resilient ring 32 and the locking recess 31a may be utilized in the modified form of the apparatus of FIGS. 10-12 if desired, FIG. 11 illustrates such modified structure with another type of resistance or detent means. Thus, the modified resistance or detent means of FIGS. 10-11 includes a resiliently urged member such as a ball 80 which is urged upwardly by a spring 81 mounted at any suitable location in the body B-1 for engagement with a portion of the ram R-1. After the ram R-1 has been moved to the open position so as to be outwardly of the body B-1, the ball 80 is resiliently urged upwardly so as to provide resistance to the return of the ram R-1 inwardly (FIG. 11). Thus, when the bonnet H-1 is thereafter disconnected from the body B-1, fluid under pressure which is supplied through the fluid conduit F-2 into the operating cylinder C-1 outwardly of the piston D acts to move the bonnet H-1 outwardly to fully expose the ram R-1. The ram R-1 also has a shoulder 83 which is adapted to engage a body extension 84 when fluid under pressure is introduced through the fluid conduit F-1 for returning the bonnet H-1 to the closed position.

The foregoing disclosure and description of the invention are illustrative and explanatory thereof, and various changes in the size, shape, and materials as well as in the details of the illustrated construction may be made without departing from the spirit of the invention.