Air shutoff swing gate valve

Abstract

An air shutoff valve includes a passage for supplying air, a swing gate, a shaft attached to a reset handle, and a spring to urge the gate toward its closed position. A trigger assembly secures the shaft and gate in the open position and includes an actuator, a cam, and a rocker arm. A cam surface of the arm has a notch to receive a sear point of the cam. Movement of the handle against the spring causes the cam contact surface of the cam to follow the cam surface to cause the arm to rotate such that the sear point is received in the notch. Actuating the actuator causes the arm to pivot away from the cam such that the sear point is released from the notch, wherein the spring causes the shaft to move the gate to its closed position.

1 . An air shutoff swing gate valve, comprising:
 a valve body having an air passage;   a valve swing gate, pivotable on a swing arm that is disposed adjacent to the valve body, wherein the valve swing gate is pivotable from an open position in which the valve swing gate is located outside the air passage to allow for flow of air through the air passage, to a closed position in which the valve swing gate is positioned within the air passage to substantially close off the air passage;   a first shaft having a longitudinal axis that extends generally perpendicular to the swing arm, wherein the swing arm is disposed on the first shaft such that rotation of the first shaft about the longitudinal axis causes rotation of the swing arm to move the swing gate between the open and closed positions;   a spring coupled to the first shaft to bias the swing arm toward the closed position; and   an actuation housing thermally isolated from the valve body,   wherein the actuation housing includes:   a trigger assembly that comprises:
 an actuator having an actuator shaft; 
 a rocker arm pivotally coupled to the actuation housing and to the actuator shaft, such that linear movement of the actuator shaft causes a corresponding rotation of the rocker arm, and 
 a cam coupled to one end of the first shaft such that rotation of the first shaft causes rotation of the cam, 
 wherein one of the rocker arm or cam includes a notch for engaging the other of the rocker arm or cam to secure the valve swing gate in the open position. 
   
     
     
         2 . The air shutoff swing gate valve of  claim 1 , wherein the air shutoff swing gate valve is coupled to an engine,
 wherein the rocker arm includes a length such that a small displacement of the actuator shaft causes a relatively larger displacement of the rocker arm to:
 provide a latching leverage associated with keeping the valve swing gate in the open position, and 
 provide a de-latching leverage in response to actuation of the actuator to move the valve swing gate to the closed position. 
   
     
     
         3 . The air shutoff swing gate of  claim 1 , wherein the actuation housing is not part of the valve body and is thermally isolated from the valve body via a seal to protect the trigger assembly from temperature extremes caused by air flow through the valve body and from the environment. 
     
     
         4 . The air shutoff swing gate valve of  claim 1 , wherein the rocker arm includes a first end coupled to the actuator shaft, a second end coupled within the actuation housing, and a curved surface located between the first and second ends and adjacent the second end,
 wherein the cam is configured to contact the curved surface of the rocker arm when the cam rotates.   
     
     
         5 . The air shutoff swing gate valve of  claim 4 , wherein the actuator shaft displaces the first end of the rocker arm linearly in response to tripping of the air shutoff swing gate valve. 
     
     
         6 . The air shutoff swing gate valve of  claim 4 , wherein the actuator, cam and rocker arm are configured to:
 maintain a first position of the rocker arm to achieve the open position of the valve swing gate against the biasing from the spring; and   establish, in response to an actuation force applied to the actuator shaft, a second position of the rocker arm to relieve the biasing from the spring to achieve the closed position of the valve swing gate.   
     
     
         7 . The air shutoff swing gate valve of  claim 4 , wherein the curved surface of the rocker arm includes the notch to receive a sear point of the cam to lock the valve swing gate in the open position. 
     
     
         8 . The air shutoff swing gate valve of  claim 7 , further comprising:
 a reset handle coupled to the first shaft, wherein the reset handle is movable to cause the sear point to move along the rocker arm and into the notch.   
     
     
         9 . The air shutoff swing gate valve of  claim 1 , wherein the actuator is mechanical, electro-mechanical, hydraulic, pneumatic, or piezo. 
     
     
         10 . The air shutoff swing gate valve of  claim 1 , wherein the actuator is an electric solenoid. 
     
     
         11 . The air shutoff swing gate valve of  claim 1 , wherein the spring comprises a torsion spring concentrically aligned with the longitudinal axis. 
     
     
         12 . A valve, comprising:
 a valve body having an air passage;   a valve swing gate, pivotable on a swing arm that is disposed adjacent to the valve body, wherein the valve swing gate is moveable from an open position in which the valve swing gate is located outside the air passage to allow for flow of air through the air passage, to a closed position in which the valve swing gate is positioned to substantially close the air passage;   a first shaft having a longitudinal axis that extends generally perpendicular to the swing arm, wherein the swing arm is disposed on the first shaft and rotation of the first shaft about the longitudinal axis causes rotation of the swing arm to move the swing gate between the open and closed positions; and   an actuation housing thermally isolated from the valve body,   wherein the actuation housing comprises:
 a trigger assembly configured to secure the swing gate in the open position and to trigger the first shaft to rotate to move from the open position to the closed position, wherein the trigger assembly comprises:
 an actuator having an actuator shaft configured to be displaced in response to triggering of the actuator, 
 a rocker arm pivotally coupled to the actuator housing and to the actuator shaft, such that linear movement of the actuator shaft causes a corresponding rotation of the rocker arm, and 
 a cam coupled to one end of the first shaft such that rotation of the first shaft causes rotation of the cam, 
 wherein one of the rocker arm or cam includes a notch for engaging the other of the rocker arm or cam to secure the valve swing gate in the open position. 
 
   
     
     
         13 . The valve of  claim 12 , wherein the valve is coupled to an engine,
 wherein the rocker arm includes a length such that a small displacement of the actuator shaft causes a relatively larger displacement of the rocker arm to:   provide a latching leverage associated with keeping the valve swing gate in the open position, and   provide a de-latching leverage in response to actuation of the actuator to move the valve swing gate to the closed position.   
     
     
         14 . The valve of  claim 12 , wherein the actuation housing is not part of the valve body and is thermally isolated from the valve body via at least one seal to protect the trigger assembly from temperature extremes caused by air flow through the valve body and from the environment. 
     
     
         15 . The valve of  claim 12 , wherein the rocker arm includes a first end coupled to the actuator shaft, and
 wherein the cam is configured to contact a surface of the rocker arm when the cam rotates.   
     
     
         16 . The valve of  claim 15 , wherein the actuator shaft displaces the first end of the rocker arm linearly in response to triggering of the actuator. 
     
     
         17 . The valve of  claim 15 , wherein the actuator, cam and rocker arm are configured to:
 maintain a first position of the rocker arm to achieve the open position of the valve swing gate against biasing from a spring; and   establish, in response to an actuation force applied to the actuator shaft, a second position of the rocker arm to relieve the biasing from the spring to achieve the closed position of the valve swing gate.   
     
     
         18 . The valve of  claim 15 , wherein the surface of the rocker arm includes the notch to receive a sear point of the cam to lock the valve swing gate in the open position. 
     
     
         19 . The valve of  claim 18 , further comprising:
 a reset handle coupled to the first shaft, wherein the reset handle is movable to cause the sear point to move along the rocker arm and into the notch.   
     
     
         20 . The valve of  claim 12 , wherein the actuator is mechanical, electro-mechanical, hydraulic, pneumatic, or piezo.