Stroke tests are carried out — without disrupting process lines — via Samson electro-pneumatic positioners.
Type 3730-3 positioner, for example, incorporates an emergency shutdown function to enable stroke tests without shutdown. It can be mounted on the valve in addition to the solenoid valve, or to replace it, says the positioner manufacturer. This enables the valve to be moved precisely to follow setpoint within valve working ratio. The partial stroke test is completely integrated into the positioner to detect a sticking valve, caused by corrosion.
With the positioners, test schedules can be flexible as required and prolonged if needed to suit use requirements.
Samson Controls (London) Ltd.
Rehill, Surrey RH1 5JQ United Kingdom
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