SAFETY SHUTOFF VALVE STRUCTURE AND METHOD
First Claim
1. Safety shutoff valve structure for maintaining a normally closed valve open until the occurrence of a predetermined condition and permitting the valve to close on the occurrence of the predetermined condition comprising a valve, means connected to the valve normally biasing the valve into a closed position, means adapted to be connected to the valve for opening the valve and retaining the valve in an open position in opposition to the means for biasing the valve into a closed position and means operably connected to the means for opening the valve and retaining it in the open position for disconnecting the means for opening the valve and retaining the valve in the open position from the valve, which last mentioned means is responsive to the predetermined condition.
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Accused Products
Abstract
Safety shutoff valve structure and method, wherein the valve is a ball valve sealed by an annular flexible seal urged into engagement with the valve by a garter spring whereby on opening the valve substantially no pressure drop is developed across the valve, and wherein a compression spring is provided for urging the valve stem in one direction to close the valve, a lever and detent means therefor are connected to the valve stem by a solenoid actuated spring clutch responsive to a predetermined condition whereby on rotating the valve stem to place the valve in an open position, the valve is maintained in the open position until occurrence of the predetermined condition. The spring clutch is operated with a uniform force not dependent on the valve opening torque or compression spring strength and the spring clutch is engaged with a force greater than the actuating force on moving the valve to an open position.
12 Citations
10 Claims
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1. Safety shutoff valve structure for maintaining a normally closed valve open until the occurrence of a predetermined condition and permitting the valve to close on the occurrence of the predetermined condition comprising a valve, means connected to the valve normally biasing the valve into a closed position, means adapted to be connected to the valve for opening the valve and retaining the valve in an open position in opposition to the means for biasing the valve into a closed position and means operably connected to the means for opening the valve and retaining it in the open position for disconnecting the means for opening the valve and retaining the valve in the open position from the valve, which last mentioned means is responsive to the predetermined condition.
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2. Structure as set forth in claim 1, wherein the last mentioned means is a solenoid actuated spring clutch and the predetermined condition is the breaking of an electric circuit through the solenoid.
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3. Structure as set forth in claim 2, wherein the valve includes a valve stem, the means biasing the valve into a closed position includes a spring connected to the valve stem to rotate the valve stem in one direction and the means for opening the valve and retaining the valve in an open position includes a shaft coaxial with the valve stem and means for rotating the shaft in a direction to open the valVe and wherein the spring clutch is operable between the valve stem and shaft.
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4. Structure as set forth in claim 3, wherein the spring clutch includes an engagement spring extending peripherally around the valve stem and shaft and wherein the solenoid is operable to move the clutch engagement spring in the same direction as the valve opening means whereby the valve opening torque is operable to increase the actuating force on the spring clutch.
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5. Structure as set forth in claim 4, wherein the clutch engagement spring and the solenoid are rotated with the valve stem and shaft on opening of the valve whereby the clutch actuating force on the clutch actuating spring is always the same and need not oppose the valve opening torque and valve closing means.
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6. Structure as set forth in claim 1, wherein the valve is a ball valve having a central opening therethrough of substantially the same dimension as the pipe in which the valve is installed whereby on opening of the valve substantially no pressure drop is developed across the valve.
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7. Structure as set forth in claim 6, wherein the ball valve is sealed with an annular flexible seal and a garter spring urging the annular flexible seal into engagement with the ball valve.
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8. The method of shutting off a valve in a gas line or the like in response to a predetermined condition comprising normally urging the valve closed with a first force, opening the valve in opposition to the first force with a larger force, holding the valve in the open position and releasing the valve from the open position and larger force on occurrence of the predetermined condition whereby the valve is urged into its normally closed position by the first force.
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9. The method as set forth in claim 8, wherein the valve is a ball valve having a stem thereon, the second force is applied to the valve stem through a shaft, and the valve stem and shaft are held together by a spring clutch, and further including initially actuating the spring clutch with a uniform force not dependent on the valve opening torque and second force.
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10. The method as set forth in claim 8, wherein the valve is a ball valve, and further including sealing the ball valve with an annular flexible seal and holding the seal in position against the ball valve with a garter spring.
Specification