US3827668A

US3827668A - Locking system for a blowout preventer

Info

Publication number: US3827668A
Application number: US00295344A
Authority: US
Inventors: Vries D De; S Gilmore
Original assignee: C Jim Stewart and Stevenson Inc
Current assignee: Baroid Technology Inc
Priority date: 1972-10-05
Filing date: 1972-10-05
Publication date: 1974-08-06
Anticipated expiration: 1991-08-06

Abstract

A locking system for a blowout preventer having a plurality of individually actuated hydraulic rams. A pilot operated locking valve for each ram for locking the ram in the closed position in which all of the locking valves are pilot operated to open and close simultaneously by two common pilot lines. The locking valves are of the positive shut-off shear-seal type. They include a hydraulic override so that if one ram is closed and locked, which puts all of the locking valves in the closed position, a second ram can still be closed by applying more pressure in the closing line of that ram than applied in the pilot closing line, all without interrupting the other locking valves.

Description

[111 3,827,668 Aug. 6, 1974 LOCKING SYSTEM FOR A BLOWOUT PREVENTER Inventors: Douwe De Vries; Samuel E.

Gilmore, both of Houston, Tex.

Assignee: C. Jim Stewart & Stevenson, Inc.,

Houston, Tex.

Filed: Oct. 5, 1972 Appl. No.: 295,344

US. Cl 251/1, 91/414, 137/495, 251/26, 251/31, 251/63.4

Int. Cl... E2lb 33/06, Fl5b 11/16, F15b 13/01 Field of Search 251/1; 166/.6; 91/411, 91/414 References Cited UNITED STATES PATENTS 12/1924 Hansen 251/1 X 6/1965 Rhodes et al. 166/.6

Primary Examiner-William R. Cline Assistant Examiner-Richard Gerard Attorney, Agent, or FirmFulbright & Cooker [57] ABSTRACT A locking system for a blowout preventer having a plurality of individually actuated hydraulic rams. A pilot operated locking valve for each ram for locking the ram in the closed position in which all of the locking valves are pilot operated to open and close simultaneously by two common pilot lines. The locking valves are of the positive shut-off shear-seal type. They include a hydraulic override so that if one ram is closed and locked, which puts all of the locking valves in the closed position, a second ram can still be closed by applying more pressure in the closing line of that ram than applied in the pilot closing line, all without interrupting the other locking valves.

3 Claims, 2 Drawing Figures Pmmtmim awn 3 ow em ,3 mm 9 ON l mm 1. ON m 7 II n. 1 .ll- I w H. mm ov r mm BACKGROUND OF THE INVENTION It is common to use blowout preventers having a plurality of rams which open and close for closing off the bore of an oil and/or gas well. The rams of the blowout preventers are generally hydraulically actuated by a piston and cylinder arrangement. In order to hold the rams in the closed position, hydraulically operated mechanical locking devices are generally employed.

Of course, suitable hydraulic lines must be led between the blowout preventer and a source of fluid power to supply the hydraulic fluid for the rams and the locking devices. If the blowout preventer is positioned underwater, it is highly desirable to have a locking device of minimum size and a minimum number of lines leading from the surface to the underwater blowout preventer. The present invention is directed to an improved locking system for a blowout preventer which utilizes a hydraulic valve far smaller than the usual mechanical device and a minimum of control lines. The versatile positive shut-off locking valves can be locked, opened, and overridden to perform the locking function for a plurality of rams.

SUMMARY The present invention is directed to providing a positive locking system for a blowout preventer having a plurality of individually actuated hydraulic rams each of which includes a special locking valve in the closing line of the ram. In order to reduce the amount of control lines, all of the pilot operated locking valves are opened and closed simultaneously with only two common pilot lines.

If one ram is closed and locked, all of the locking valves are placed in the closed position since they are all operated by common pilot lines. Another feature of the present invention is the ability of the locking system to close a second ram without opening the locking valves by providing the locking valves with a hydraulic override which is actuated by applying more pressure in the closing line of the ram desired to be closed then applied on the locking valve through the pilot line. The override feature allows a locked valve to be opened, in order to close its connected ram, without affecting the other locking valves on the other rams in the blowout preventer.

The present invention is further directed to a pilot operated locking valve having an override in which a valve element moves between an open and close position and is controlled by pilot actuated pistons. The piston opening the valve has an area exposed to the valve inlet in a direction to open the valve. When a greater force is applied from the valve inlet against the opening piston than the closing force acting on the closing piston, the valve will be overridden and opened to allow passage of fluid therethrough, but will close when the inlet pressure is reduced.

Yet a further object is the provision of an override locking valve wherein the opening piston includes first and second separate but adjacent portions in which the second portion includes a piston ring and is exposed to the pilot opening line and the first portion includes a passageway in communication between the valve inlet and one end of the first portion for providing an override force from the valve inlet against the valve element.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an elevational view, in cross section, of the pilot operated locking valve of the present invention, and

FIG. 2 is a schematic view, partly in cross section, of a locking system for a blowout preventer.

BRIEF DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings, and particularly FIG. 2, the reference numeral 10 generally refers to a conventional blowout preventer having a plurality of

rams

12, 14, 16 and 18. Each of the rams conventionally has a hydraulic closing line and a hydraulic opening line. Thus, the

rams

12, 14, 16 and 18 each includes a

closing line

20, 22, 24 and 26, respectively. In addition, each of the

rams

12, 14, 16 and 18 includes a

hydraulic opening line

28, 30, 32 and 34, respectively. The rams may be conventional double acting piston and cylinder operated rams which close when hydraulic fluid is transmitted through their closing line while exhausting fluid through the opening line, and open when hydraulic fluid is transmitted through their opening line while exhausting fluid through their closing line. Of course, if the blowout preventer 10 is on the ocean floor underwater, the

closing lines

20, 22, 24 and 26 and the

opening lines

28, 30, 32 and 34 must lead to the water surface to a hydraulic fluid power source for actuating the rams to the closed or opened position such as to

shuttle valves

21, 23, 25 and 27, respectively, which preferably lead to two power sources.

The locking system of the present invention includes

identical locking valves

40a, 40b, 40c and 40d in each of the

closing lines

20, 22, 24 and 26, respectively, which open to allow closing hydraulic fluid to pass to one or more of the

rams

12, 14, 16 and 18 for closing the rams. After a ram is closed, a locking valve must be closed to lock the ram closing pressure in to maintain the closed ram in a closed and locked position. When the rams are to be opened, the locking valve must open to allow the closing fluid in the closing lines to exhaust through the locking valves. Each of the

locking valves

40a, 40b, 40c and 40d are pilot operated to be opened or closed. In order to reduce the number of lines leading to the blowout preventer 10, particularly when the blowout preventer 10 is underwater, a single pilot closing control line 42 and a single pilot opening control line 44 are provided connected to each of the

locking valves

40a, 40b, 40c and 40d for simultaneously applying a hydraulic closing or opening force to all of the locking valves.

Referring now to FIG. 1, a single locking valve 40ais shown and the remainder of the

locking valves

40b, 40c and 40d are identical in structure and function. The valve 40a includes an inlet 46 and an outlet 48 both of which are connected in the closing line 20 for passage and exhaust of hydraulic fluid therethrough to and from the ram 12. Valve 40a includes a valve element I 50 such as a shear-seal type element adapted to be tion to the pilot opening control line 44. A pilot closing piston 56 is provided in communication with the closing port 52 and the closing control line 42 which moves the valve element 50 to the closed position when pressure is applied to the closing control line 42. A pilot opening piston generally indicated by the reference numeral 60 is provided in communication with the opening port 54 and opening control line 44 and is responsive to fluid pressure therein for indirectly moving the valve element 50 upwardly by pushing a valve element carrier 62. Valve element carrier 62 serves also as the primary opening piston subject to pressure applied between secondary opening piston 60 and itself. The secondary opening piston 60 includes a piston ring or seal 66 whereby the first portion 60 will be movable in response to fluid pressure in the opening controlline 44. The primary piston and carrier 62 includes a piston ring or seal 64, a port 68 and a passageway 70 leading to the cavity between

items

60 and 62. It is to be noted that the port 68 and passageway 70 are in fluid communication with the valve inlet 46 for allowing fluid from the inlet 46 to pass to the underside of the carrier piston 62 to create a hydraulic override to move seal 50 to open the valve 40a even when the valve 400 has moved to the closed position by the closing pilot piston 56.

Assume that all of the

rams

12, 14, 16 and 18 of the blowout preventer are open and it is desired to close one of the rams, for example ram 12. In that event, control pressure is transmitted through pilot opening control line 44 and is applied against the pilot opening piston 60 in the locking valve 40a and against the pilot opening pistons in all of the other locking valves 40]), 40c and 40d since all of the locking valves operate simultaneously from the two

common pilot lines

44 and 42. Fluid pressure against the back of the secondary piston 60 moves the carrier 62 and thereby the valve element 50 away from outlet port 48 allowing communication between the inlet 46 and outlet 48 of the locking valve 40a, thereby opening valve 40a. Hydraulic fluid is then transmitted through closing line and locking valve 40a to the ram 12 for closing the ram 12. Fluid pressure in the pilot opening control line 44 is bled off and fluid pressure is exerted through the pilot closing control line 42 which is applied to the closing port 52 behind the closing pilot piston 56 which now moves the valve element 50 into position over outlet port 48, as best seen in FIG. 1, blocking communication between the valve inlet 46 and the valve outlet 48 thereby locking the ram 12 in the closed position as soon as the fluid pressure in the closing line 20 is bled off. Since only the

single control lines

42 and 44 are used, the closing of locking valve 40a closes all of the

other locking valves

40b, 40c and 40d even though the

rams

14, 16 and 18 remain in the open position.

In the event that it is then desired to close a second ram, such as ram 14, the closed locking valve 401) would then be overridden by applying a greater pressure through the closing line 22 of ram 14 than is applied to the locking valve 40b through the pilot closing control line 42. For example only, the pilot pressure in the

control lines

42 and 44 may be 1,500 psi and if 2,000 psi hydraulic pressure is applied through the closing line 22, the locked locking valve 40b will be temporarily opened by the pressure in the closing line 22, without affecting the

other locking valves

40a, 40c and 40d until the ram 14 is closed, and after which, the locking valve 40b will thereafter close again to hold the ram 14 in the closed position. That is, the higher pressure in the closing line 22 will pass through the inlet 46 of the valve 40b and through the port 68 and passageway to the underside of the primary opening piston and carrier 62 and overcome the force of the lower pressure of the pilot closing line 42 acting on the pilot closing piston 56. The higher force acting on the piston portion 62 will move primary piston 62 upwardly moving the valve element 50 away from the outlet 48 allowing fluid communication of the higher pressure from the inlet 46 through the outlet 48 and the closing line 22 to close the ram 14. As soon as ram 14 has been closed, the higher closing pressure in the closing line 22 is bled off and when the pressure in the closing line 22 is decreased below the pressure in the pilot closing line 42 the pilot closing pressure in line 42 will again force the pilot closing piston 56 downwardly moving the valve element 50 into a closed position and locking the ram in the closed position by holding the fluid behind the double acting ram 14. During this operation of closing the ram 14 the

other locking valves

40a, 40c and 40d will remain locked.

The present invention, therefore, is well adapted to carry out the objects and attain the ends and advantages mentioned as well as others inherent therein. While a presently preferred embodiment of the invention has been given for the purpose of disclosure, numerous changes in the details of construction and arrangement of parts may be made which will readily suggest themselves to those skilled in the art and which are encompassed within the spirit of the invention and the scope of the appended claims.

What is claimed is:

l. A locking system for a blowout preventer having a plurality of hydraulically operated rams comprising,

a pilot operated locking valve for each ram, each said valve having an inlet and an outlet, the outlet of each valve connected to one of the rams and the inlet of each valve connected to a separate source of hydraulic fluid for closing the connected ram,

each valve having a pressure operated valve element for opening and closing communication between the valve inlet and the outlet,

at single pilot control line connected to all of the valves on one side of the valve elements for closing all of the valves thereby locking any of the rams that have been closed in the closed position,

a single pilot control line connected to all of the valves on a second side of the valve elements for opening all of the valves, and

an area on each valve element on said second side exposed to the inlet, said area being sufficiently large to open the associated valve when an overriding pressure is provided at the inlet of any one valve greater than the pressure in the pilot control line closing said one valve thereby opening said one valve and closing the ram connected to said one valve.

2. A locking system for an underwater blowout preventer having a plurality of hydraulically operated rams comprising,

a valve element in each said valve for opening and closing communication between the valve inlet and the outlet,

a first piston on one side of each valve element,

a pilot closing port in each valve communicating with the first piston for supplying fluid against the first piston for moving the element to the closed position,

a single pilot closing control line connected to all of the pilot closing ports for closing all of the valves thereby locking any of the rams that have been closed in the closed position,

a second piston on a second side of each of the valve elements,

a pilot opening port in each valve communicating with the second piston for supplying fluid against the second piston for moving the element to the open position,

the pilot opening ports for opening all of the valves,

each said second piston having an area exposed to the valve inlet in a direction to open said valve when a greater force is applied from the valve inlet against the second piston area than the closing force on the first piston.

3. The aparatus of claim 2 wherein the second piston includes first and second separate adjacent portions, the second portion including a piston ring, and the first portion including a passageway in communication between the valve inlet and the end of the first portion remote from the valve element, said second portion being positioned between the first portion and the pilot opening port.

Claims

1. A locking system for a blowout preventer having a plurality of hydraulically operated rams comprising, a pilot operated locking valve for each ram, each said valve having an inlet and an outlet, the outlet of each valve connected to one of the rams and the inlet of each valve connected to a separate source of hydraulic fluid for closing the connected ram, each valve having a pressure operated valve element for opening and closing communication between the valve inlet and the outlet, a single pilot control line connected to all of the valves on one side of the valve elements for closing all of the valves thereby locking any of the rams that have been closed in the closed position, a single pilot control line connected to all of the valves on a second side of the valve elements for opening all of the valves, and an area on each valve element on said second side exposed to the inlet, said area being sufficiently large to open the associated valve when an overriding pressure is provided at the inlet of any one valve greater than the pressure in the pilot control line closing said one valve thereby opening said one valve and closing the ram connected to said one valve.

2. A locking system for an underwater blowout preventer having a plurality of hydraulically operated rams comprising, a pilot operated locking valve for each ram, each said valve having an inlet and an outlet, the outlet of each valve connected to one of the rams and the inlet of each valve connected to a separate source of hydraulic fluid for closing the connected ram, a valve element in each said valve for opening and closing communication between the valve inlet and the outlet, a first piston on one side of each valve element, a pilot closing port in each valve communicating with the first piston for supplying fluid against the first piston for moving the element to the closed position, a single pilot closing control line connected to all of the pilot closing ports for closing all of the valves thereby locking any of the rams that have been closed in the closed position, a second piston on a second side of each of the valve elements, a pilot opening port in each valve communicating with the second piston for supplying fluid against the second piston for moving the element to the open position, a single pilot opening control line connected to all of the pilot opening ports for opening all of the valves, each said second piston having an area exposed to the valve inlet in a direction to open said valve when a greater force is applied from the valve inlet against the second piston area than the closing force on the first piston.