Fluid handling – Destructible or deformable element controlled – Heat destructible or fusible
Reexamination Certificate
2000-03-24
2001-05-08
Buiz, Michael (Department: 3753)
Fluid handling
Destructible or deformable element controlled
Heat destructible or fusible
C137S070000, C137S079000, C166S069000
Reexamination Certificate
active
06227226
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to industrial safety equipment. In particular, the present invention relates to the automatic operation of fluid control valves in the event of fire in the proximity of the valve body.
2. Description of the Related Art
Release of well control fluids such as water, chemical suppressants or well plugging foams, often depends upon the operation of a fluid line valve. Depending upon the specific fluid control system, certain valves must be opened or closed at a critical moment.
Many fire control systems are under the positive control of sensors that activate externally powered controllers and valve motors. Some fire risk activities, however, such as gas and oil wellheads, are not well suited for powered actuation due to remoteness of the wellhead location. Although fire control fluid systems may be and are installed at remote wellheads, the unavoidable fact remains that the critical valves must be manually operated. At odds with this fact is the dilemma of those facilities and installations whereat the critical valve or valves must be located in the proximity of where such a fire would, in greatest probability, occur. Here, the critical fire control valves may be enveloped in flame and therefore hazardous if not impossible to be manually operated when needed.
It is an object of the present invention, therefore, to provide a valve construction that operates without manual intervention in the presence of fire or excessive heat.
Another object of the present invention is provision of a fluid control valve that opens or closes, as required, in the presence of fire or excessive heat.
A further object of the present invention is a wellhead control assembly having a well fluid control system that is initiated by a heat fused valve.
SUMMARY OF THE INVENTION
These and other objects of the present invention are accomplished by a valve construction wherein the valve operating stem is biased to a “fail-safe” position by fluid pressure within the pipe served by the valve. For example, well or fire control fluid flow from a supply pipeline is blocked by a valve gate having a reversely translating control stem. Fluid pressure within the supply pipeline exerts a bias on the gate and control stem to urge the gate toward the open pipeline flow position. This line pressure bias is opposed by external fluid pressure applied to an operating cylinder upon the face of the associated stem operating piston or diaphragm. This external fluid pressure is usually applied by a manual pump. Release of the external fluid pressure allows the pipeline pressure to open (or close) the valve as required. At the closed position, the gate setting is maintained against the pipeline pressure by closing the flow port that admits the external pressure.
Adjunctive to the foregoing valve construction, opening movement of the valve gate stem is restrained by a eutectic material cap block that is thermally fusible at a predetermined, relatively low temperature such as 300° F., for example. External fluid pressure within the gate valve operating cylinder is released and the cylinder vented to allow the pipeline pressure to open the valve but for the cap block obstruction. Accordingly, pipeline pressure causes the gate stem to bear against the fusible cap block.
In the event of fire in the proximity of the valve, the fusible cap block is heated. When the desired heat of fusion is attained, the valve stem is pushed through the heat softened eutectic material by the pipeline pressure bias thereby opening the “kill fluid” supply line.
REFERENCES:
patent: 3958592 (1976-05-01), Wells et al.
patent: 4421134 (1983-12-01), Bruton et al.
patent: 4505291 (1985-03-01), Bruton
patent: 4635670 (1987-01-01), Kilmoyer
patent: 4947886 (1990-08-01), Grove
Baker Hughes Incorporated
Buiz Michael
Krishnamurthy Ramesh
Madan Mossman & Sriram P.C.
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