Title:
Blowout preventer with locking means
United States Patent 3918478


Abstract:
A blowout preventer with at least one movable bonnet and an operating cylinder which may be moved outwardly from the body of the preventer to a ram-exposed position by fluid pressure in an operating cylinder and piston so that a ram in the preventer is accessible for replacement or repair, and having locking means to lock the piston to the body of the blowout preventer.



Inventors:
LE ROUAX ROBERT K
Application Number:
05/441380
Publication Date:
11/11/1975
Filing Date:
02/11/1974
Assignee:
HYDRIL COMPANY
Primary Class:
Other Classes:
92/128, 251/1.3, 277/323, 277/325
International Classes:
E21B33/06; (IPC1-7): E21B33/06
Field of Search:
251/1 277
View Patent Images:
US Patent References:



Primary Examiner:
Schwadron, Martin P.
Assistant Examiner:
Gerard, Richard
Attorney, Agent or Firm:
Pravel & Wilson
Claims:
I claim

1. A blowout preventer, comprising:

2. The structure of claim 1, wherein said piston has an inner side and an outer side responsive to fluid pressure and wherein said pressure means includes:

3. The structure of claim 1, wherein:

4. The structure of claim 1, wherein said body rod means comprises:

5. The structure of claim 4, wherein said piston has an inner side and an outer side responsive to fluid pressure and wherein said pressure means includes:

6. The structure of claim 4, wherein:

7. The structure of claim 6, wherein said locking means comprises:

Description:
BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to blowout preventers.

2. Description of the Prior Art

It has often been necessary or desirable to replace the rams or the sealing components of such rams while the preventer is mounted at a wellhead in the field. The ram cylinder and bonnet were moved outward from the preventer body to provide access to the ram for repair or replacement thereof.

In U.S. Pat. No. 3,670,761 of the present inventor, and assigned to the assignee of the present invention, the operating cylinders of the rams were used to cause this movement of the ram cylinders and bonnets, providing advantages over prior art patents cited therein. In U.S. Pat. No. 3,670,761, split rings mounted with body rods expanded into recesses in an operating piston to permit movement of the ram cylinders and bonnets. These split rings were mounted within the ram cylinder and thus not exposed to well fluids. However, the split rings within the ram cylinder were not visible to the operator and it was sometimes a problem to determine if they are properly seated. Further, the split rings were subjected to wear and fatigue due to the repeated engagement and disengagement within the recesses in the piston during ram repair or replacement.

SUMMARY OF THE INVENTION

Briefly, the present invention provides a new and improved blowout preventer wherein the ram of such preventer is moved into a ram-exposed position where the ram is accessible for replacement, repair or similar servicing operations.

A bonnet is detachably connected with the body of the blowout preventer and is adapted to receive the ram of the preventer when the ram has been moved to an open position where the bore of the blowout preventer body is unobstructed. An operating cylinder is connected to the bonnet for movement therewith, and has a piston therein to which the ram is connected so that fluid pressure supplied to the cylinder moves the ram between the open position and a closed position where the ram extends into the bore of the preventer body. A locking means locks the piston against movement with respect to the blowout preventer body so that the bonnet may be detached from the body and fluid pressure supplied to the operating cylinder to move the operating cylinder and bonnet outwardly from the preventer body to expose and provide access to the ram for replacement, repair or other servicing operations.

It is an object of the present invention to provide a new and improved blowout preventer.

It is an object of the present invention to provide a new and improved method of moving a blowout preventer ram into a position accessible for replacement or repair operations.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an elevation of the apparatus of the present invention, illustrating the left-hand bonnet in the ram-exposed position and the right-hand bonnet in the closed connected position;

FIG. 2 is a sectional view partly in elevation, illustrating the left-hand portion of the apparatus of FIG. 1, but showing the bonnet in the closed connected position, with the ram in the closed position;

FIG. 3 is a cross-sectional view taken on the line 3--3;

FIG. 4 is a view similar to FIG. 2, but showing the ram locked in the open or retracted position, with the bonnet in the closed connected position, such view like FIG. 2, being taken on line 2--2 of FIG. 3;

FIG. 5 is a view similar to FIGS. 2 and 4, but taken on line 5--5 of FIG. 3, and illustrating the bonnet in the ram-exposed position to permit removal and replacement thereof; and

FIG. 6 is a cross-sectional view taken along the lines 6--6 of FIG. 5.

DESCRIPTION OF PREFERRED EMBODIMENT

In the drawings, the letter A designates generally the blowout preventer of the present invention which is connected in the usual way to well casing or pipe P, using bolts 10, or other suitable means, which extend through a flange 12 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 or bore 14 therethrough which is aligned with the vertical opening through the casing or the pipe P. The body B also has laterally disposed ram openings 16 (one of which is shown in FIG. 2) 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 14. A ram R of any suitable construction is mounted so that it is laterally movable in one of the lateral ram openings 16, and each of such rams R has a suitable sealing assembly 18 formed of rubber or similar material in the usual manner. The rams R are adapted to be moved laterally from the closed position (FIG. 2) in which position they extend into the bore 14, to an open position in normal operation, wherein the central bore 14 is unobstructed and open for performing normal well operations therethrough.

Furthermore, as will be set forth more in detail, the blowout preventer A is constructed with a bonnet H for each of the rams R so that each bonnet H encloses one of the rams R on each side of the preventer body B. Each of the bonnets or heads H is releasably or detachably connected to the body B with bolts 20 (FIG. 1) or any suitable releasable securing means in the known manner. An operating cylinder C is secured to the bonnet H by bolts 22 (FIG. 1) or any other suitable securing means so that the cylinder C is secured to and movable with the bonnet H. A piston D is slidably positioned within the cylinder C (FIGS. 2, 4 and 5), and each piston is connectd to one of the rams R by a piston rod 24 so that movements of the piston D are transmitted to the ram R connected therewith. As will be set forth below, hydraulic fluid under pressure is supplied to the cylinder C, preferably through fluid conduits F-1 (FIGS. 2 and 4) and F-2 (FIG. 5) in order to move the piston D within the cylinder C for moving the ram R therewith to and from the closed and opened positions. Also, when the bonnet H is disconnected from the body B by the release of the bolts 20, and the piston D locked against movement with respect to the body B in the manner to be set forth below, the fluid pressure in the cylinder C is used 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, replacement, repair or like servicing operations. The fluid presssure 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 reconnecting the bonnet H to the preventer body B for subsequent 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 right-hand ram and the parts therewith are generally the same.

Considering the ram R more in detail, the ram R may have a generally oval shape or cylindrical shape or it may be of any other suitable shape so as to properly function within its ram opening 16 in the body B. The ram R is releasably connected to the piston rod 24 by means of a connector button 26 disposed in a suitable slot, such as a lateral or transverse slot or a vertical slot. The diameter or dimensions of the button 26 are larger than the diameter or dimensions of the piston rod 24 so that the buttom 26 fits with a channel 28 to releasably retain the ram R on the rod 24. Using suitable connecting constructions, such as those set forth in the U.S. Pat. No. 3,670,761, the ram R may be removed in either a lateral direction or vertically, depending upon the space available after the ram R has been moved to the ram-exposed position (FIG. 5). The button 26 may have a square or rectangular shape, or it may be round or of other shape so long as it extends into the channel 28 when in the connected position with the ram R.

As has been set forth, the preventer A is preferably constructed in an identical manner on each side of the body B. Thus, the left-hand bonnet H has extending therethrough a pair of body rods or extensions 30 and 32 which extend into the operating cylinder C, through the piston D as will be more fully explained. The body rod 30 is connected by threads 30a to the body B and forms an extension thereof which serves as one of the supports for the bonnet H when it is in the open or ram-exposed position (FIG. 5). The body rod 32 is similarly connected to the body B at threads 32a and forms the other support for the bonnet H in such ram-exposed position. Suitable seals such as 30' and 32' are provided as part of, or adjacent to, the threads 30a and 32a to prevent fluid leakage at such points.

The body rods 30 and 32 have enlargements 30b and 32b, respectively, which fit within bonnet cylinders 34 and 36, respectively. O-rings 30c and 32c formed of rubber or similar sealing material are disposed in enlargements 30b and 32b, respectively, for sealing engagement with the inside surface of the cylinders 34 and 36, respectively.

The body rod 30 (FIG. 2) extends through a fluid cylinder lobe 38 of the cylinder C and therefrom through an opening 40 formed in an outer end wall 42 of the cylinder C. An O-ring 40a of rubber or other suitable material provides a seal with the external surface of the body rod 30 in the opening 40.

In a like manner, the body rod 32 (FIG. 5) extends through a fluid cylinder lobe 44 of the cylinder C and therefrom through an opening 46 formed in the outer end wall 42 of the cylinder C. An O-ring 46a of rubber or other suitable material provides a seal with the external surface of the body rod 32 in the opening 46.

A locking mechanism L is mounted with the body rods 30 and 32 (FIGS. 1, 2, 4, 5 and 6) externally of the cylinder C to engage and lock the piston D against movement with respect to the body B in a manner to be set forth below. A first locking dog 48 of the locking mechanism L (FIG. 6) is pivotally mounted with respect to the body rod 30 adjacent an outer end portions 30d thereof. Similarly, a locking dog 50 of the locking mechanism L is pivotally mounted with respect to the body rod 32 adjacent an outer end portion 32d thereof (FIG. 5). The locking dogs 48 and 50 are normally in a downwardly extending position (shown in phantom in FIG. 2) to permit outward movement of the piston D.

The piston D is mounted for movement within a tubular sleeve 52 in the cylinder C. An O-ring 54 of suitable sealing material is mounted with the piston D to provide a seal with the external surface of the piston D in the sleeve 52 (FIG. 2).

The sleeve 52 is mounted adjacent a circular opening formed at a surface 56a in a bulkhead 56 within the cylinder C (FIG. 2) with an O-ring 56b or other suitable seal mounted therein for sealing purposes.

Openings are formed adjacent surfaces 58 (FIG. 2) and 60 (FIG. 5) in portions of the bulkhead 56 extending outwardly to form end walls for the cylinder lobes 38 and 44, respectively, of the cylinder C. An O-ring 58a is mounted to provide a seal between the opening adjacent the surface 58 and the external surface of the body rod 30, while an O-ring 60a is mounted to provide a seal between the opening adjacent the surface 60 and the external surface of the body rod 32 (FIG. 5).

The fluid conduit F-1 includes a passage 30e (FIG. 4) in the body rod or extension 30 leading from a fluid passage 66 in the body B, which communicates through a suitable opening 66a (FIG. 1) with a source of hydraulic fluid under pressure. The passage 30e discharges through a port 30f into an area of the operating cylinder C inwardly of the piston D. An opening 52a is formed in the sleeve 52 (FIG. 2) to permit the fluid pressure from the fluid conduit F-1 to act on an inner side of the piston D.

The fluid conduit F-2 (FIG. 5) includes a longitudinal passage 32e through the body rod or extension 32 which is in communication with a fluid passage (FIG. 5) in the body B and which is in communication with a source of hydraulic fluid under pressure. The passage 32e discharges through a port 32f (FIG. 5) into the cylinder lobe 44 in the cylinder C. An opening 52b is formed at an outer end of the sleeve 52 so that the fluid in the cylinder lobe 44 discharges into an area of the operating cylinder C outwardly of the piston D to permit the fluid pressure from the fluid conduit F-2 to act on an outer side of the piston D.

Since the apparatus of this invention is illustrated with its essential components rather than the refined construction and variations which may be utilized in actual manufacture, the details with respect to such things as the seal rings have been omitted in some cases, but seal rings are shown in the drawings to illustrate the separation of the various fluids that are present in this system. Thus, a seal ring 70 is mounted in the bonnet H in an opening 72 through which the piston rod 24 moves for providing a fluid seal with the external surface of the rod 24. An O-ring 74 is also illustrated to show a seal between the bonnet H and the body B when the bonnet H is in the closed position (FIG. 2). A seal 76 is also provided between the operating cylinder C and the bonnet H (FIG. 4).

The piston D further has a piston rod 78 formed therewith extending outwardly through an opening 80 formed in the outer end wall 42 of the cylinder C. An O-ring 80a provides a seal with the external surface of the piston rod 78 in the opening 80. A reduced-diameter, recessed portion 78a is formed adjacent an outer end 78b of the piston rod 78 for engagement with the locking mechanism L.

Considering the locking mechanism L more in detail, the locking dog 48 includes a support arm 48a (FIG. 6) pivotally mounted with the body rod 30 and a locking arm portion 48b which has an arcuate surface 48c formed thereon. The locking dog 50 includes a support arm 50a pivotally mounted with the body rod 32 and a locking arm portion 50b which has an arcuate surface 50c formed thereon. The locking dogs 48 and 50 may be pivoted manually or by using a suitable tool or power source, with respect to their respective body rods 30 and 32.

The arcuate surfaces 48c and 50c of the locking dogs 48 and 50 are adapted to fix about and engage the reduced-diameter, recessed portion 78a of the piston rod 78. The locking arm portions 48b and 50b of the locking dogs 48 and 50, respectively, are substantially equal in width to the width of the recessed portion 78a of the piston rod 78. Thus, the arcuate surfaces 48c and 50c of the locking dogs 48 and 50 engage the piston rod 78 at the reduced-diameter portion 78a, and the locking arm portions 48b and 50b adjacent such arcuate surfaces fit within the recess formed in the piston rods 78 adjacent the recessed portion 78a, thereby locking the piston D against movement with respect to the body B so that, as will be set forth, the bonnet H can be detached from the body B and moved away therefrom in order to provide access to the ram R.

In the operation or use of the apparatus A of this invention, the bonnet or head H is normally secured to the body B by means for the connecting bolts 20 or other suitable attaching means. Therefore, for normal operation of each ram R fluid under pressure is introduced into its respective cylinder C outwardly of the piston D for moving the ram R inwardly to completely close the longitudinal central opening 14 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 portion for completing the closure of the opening 14, as is known. If the ram R is shaped for fitting around the external surface of a well pipe in the opening 14, then the two opposed rams close off the opening 12 around such well pipe, as is understood by those skilled in the art.

When it is desired to move each of the rams R to the open position in order to leave the bore or opening 14 completely open, fluid under pressure is introduced through each fluid conduit F-1 for each of the rams R. The description set forth below deals with a single one of the rams R (left-hand ram as illustrated in the drawings), but it will be appreciated that such explanation applied equally as well to the right-hand ram R.

Hydraulic fluid under pressure is introduced through the fluid conduit F-1 into the cylinders C and through the opening 52a in the sleeve 52 inwardly of the piston D against an inner side thereof to thereby move the piston D to an open position wherein the bore 14 in the body B is unobstructed and the ram R is disposed outwardly of the ram opening in the body B. The hydraulic fluid used to cause such movement of the piston D may be provided by any suitable source of pressure (not shown) through the passage 66 in the body B and the passage 30e and the port 30f in the body rod 30.

In the normal blowout preventer operations, the bonnet H thus remains connected to the body B, and the ram R is moved back and forth as desired for controlling the opening and closing of the bore 14 through the body B.

When it is desired to move the ram R to the exposed position (FIG. 5) in order to provide access to the ram R for removal, replacement, repair or other service operations, the ram R is first moved to the open position. The locking dogs 48 and 50 are pivoted with respect to the body rods 30 and 32 so that the arcuate surfaces 48c and 50c thereof fit within and engage the recessed portion 78a of the piston rod 78 (FIG. 4). It is to be noted that the locking dogs 48 and 50 are mounted externally of the cylinder C so that an operator may readily determine whether the piston D is locked in place with respect to the body B. Further, the locking mechanism L is not exposed to well fluids or other operating fluids of the blowout preventer.

The locking mechanism L when engaged with the piston rods 78 locks the piston D against movement with respect to the body B. After the piston D has been locked against movement with respect to the body B by the locking mechanism L, the bolts 20 between the bonnet H and the body B are disconnected, and fluid under pressure is supplied through the fluid conduit F-2, including the passage 68 in the body B (FIG. 5) the passage 32e and the port 32f into the cylinder lobe 44 and therefrom through the opening 52b to act on an outer side of the piston D.

Since the piston D is locked against movement with respect to the body B by the locking mechanism L, and since the cylinder C is attached to the bonnet H by bolts 22, and the body rods 30 and 32 support the bonnet H and the cylinder C, the fluid pressure provided through the fluid conduit F-2 to the cylinder C acts to move the cylinder C outwardly while the piston D remains locked against with respect to the body B. In this manner, the operating cylinder C in the bonnet H is moved outwardly with respect to the body B in order to fully expose and provide access to the ram R (FIG. 5). The body rods 30 and 32 provide support for the bonnet H and the other parts therewith during such movement and when the ram R is in the ram-exposed position. If desired, additional support may be provided by other structure or means (not shown), such as an extension from the body B upon which the ram R may rest. When the ram R is in the ram-exposed position (FIG. 5) it may be removed either laterally in either direction or vertically, as has been set forth.

In order 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 opening 52a formed in the sleeve 52 to act on the inner side of the piston D. The piston D is locked against movement with respect to the body B, so that the fluid pressure acting on the inner side of the piston D causes inward movement of the bonnet H and the cylinder C with respect to the piston D and the body B and the cylinder C and the bonnet H move inwardly from the outer open or ram-exposed position (FIG. 5) to an inner closed position (FIG. 4). The bolts 20 or other suitable connecting means are then reattached in order to secure the bonnet H to the body B so that normal ram operations of the ram R may thereafter continue.

From the foregoing, it can be seen that the blowout preventer described herein provides for a means to lock the piston D externally of the operating cylinder C relative to the body B and thereby prevent relative movement of the ram R relative to the body B in order to open and close the bonnet H with respect to the body B. The operating cylinder C and the hydraulic power provided therewith for ram movement operations are thus used rather than requiring auxiliary or supplemental hydraulic systems and cylinders.

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.