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Partial stroke testing (or PST) is a technique used in a control system to allow the user to test a percentage of the possible failure modes of a shut down valve without the need to physically close the valve. PST is used to assist in determining that the safety function will operate on demand.
Proof test - A manual test that allows the operator to determine whether the valve is in the "as good as new" condition by testing for all possible failure modes and requires a plant shutdown Diagnostic Test - An automated on-line test that will detect a percentage of the possible failure modes of the shutdown valve.
One example of SIS is a temperature sensor that provides a signal to a controller, which compares the sensed process temperature to the desired temperature setpoint and sends a signal to an emergency on-off valve actuator which stops the flow of heating fluid to the process if the process temperature is exceeded by an unsafe margin.
A manifold pressure regulating shut-off valve (MPRSOV) restricts the flow as necessary to maintain the desired pressure for downstream systems. A certain minimum supply pressure is needed to drive the air through the system, but it is desired to use as low a supply pressure as possible, because the energy the engine uses to compress the bleed ...
Surge control products have been used in many industries to protect the maximum working pressure of hydraulic system for decades. Typical applications for surge relief equipment is in pipelines at pump stations, receiving manifolds at storage facilities, back pressure control, marine loading/off loading, site specific applications where pressure surges are generated by the automation system ...
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Increased pressure or decreased pressure closes the valve (without using any external power sources). Installing a bypass pipe with a pushbutton to open valve (normally spring closed valve) between the inlet and outlet of the security valve can let the upstream and downstream pressure can be equalized on both sides of the security valve, so it ...
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