Fluid Operated Safety Valve (Patent No: 869315)

Inventor: Zerb, Donald L.

Location: Edmonton

Comments: N/A

Description: The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. In a fluid operated safety valve, the combination of a valve body provided with an elongated cavity defining a valve chamber in one end portion, a cylinder in the other end portion, and a diametrically restricted passage extending between said chamber and said cylinder in the intermediate portion of said valve body, said chamber having a fluid inlet and also having a valve seat at the junction of the chamber with said restricted passage, a fluid outlet extending laterally from the restricted passage to one side of the valve body, a valve stem slidable axially in said valve body cavity between a valve-closed and a valve-open position, said valve stem including an intermediate piston in sealing engagement with said restricted passage at a point between said fluid outlet and said cylinder whereby to block communication between
said valve chamber and the cylinder, an enlarged valve member provided at an end of said stem in said chamber for engagement with said valve seat when the stem is slid to the valve-closed position by excessive fluid pressure in said chamber, an actuating piston provided on said stem and reciprocable in said cylinder, and means for delivering fluid under pressure into said cylinder for sliding said actuating piston and said valve stem to the valve-open position wherein said valve member is disengaged from said seat to establish communication between said fluid inlet and outlet when fluid pressure in said chamber is not excessive.

2. The device as defined in claim 1 together with a valve piston provided on said stem adjacent said valve member, said valve piston being sealingly received in said restricted passage when the stem is in the valve-closed position.

3. The device as defined in claim 2 wherain said valve stem includes a diametrically reducad portion between said valve piston and said intermediate piston, said reduced stem portion facilitating fluid flow from said chamber to said outlet through said restricted passage in the valve-open position of the stem.

4. The device as defined in claim 1 together with resilient means provided in said cylinder and reaoting against said actuating piston to bias said stem to the valve-closed position.

5. The device as defined in claim 1 wherein said valve stem has an end portion projecting outwardly through the cylinder end of said valve body.