Fisher® 644 and 645 actuators are used in combination with any of several sliding-stem valves to automatically control steam-driven boiler feedwater pumps (reciprocating or turbine). The 644 or 645 actuator, when used in combination with one of several push-down-to-close sliding-stem valves, forms a pump governor.
644 and 645 actuators may also be combined with push-down-to-open valves to be used as relief governors. Relief governors are used to divert excess pump discharge back to the suction side of the pump.
Features & Benefits
Rugged Construction—Steel and cast iron construction provides long service life.
Ease of Maintenance—Few moving parts and easy access reduce maintenance and downtime.
Ease of Adjustment—Spring adjustment is readily accessible without removing any parts.
Fast Acting—Direct-operated configuration provides fast speed of response.
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