The underlying concept of all SafetySIL products is to interconnect all components of the system in such a way that a Full-Function Test can only be completed if all individual components are functioning correctly.

The SafetySIL Emergency Shutdown Block Valve can be thought of as a parallel differential flowmeter.  When one valve is closed during a Full-Function Test, a particular level of differential pressure will be generated between the outlets of the opened valve and the closed valve, but only if the closed valve is completely closed.  This way, when one valve is closed and tested, then opened again with the alternate valve closed and tested, the proper operation of both valves can be verified at the level of the process.

Thus, the system allows for a Full-stroke Function Test to be applied to both parallel valves while the process continues to operate.

When manual block valves are included in the system, its operation becomes fault-tolerant, allowing for the detection of hidden faults and their repair while the process continues to operate.  In this manner, both Production and Safety are maximized.




U.S. Patents

Cycling Self Checking Block Valve

Patent Number: 6,058,956

Cycling, Self Checking Pressure Sensing System

Patent Number: 6,053,193

Cycling, Self Checking Pressure Sensing System

Patent Number: 6,422,257