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Series 2G Diaphragm Actuators 

Designed for snap or throttling service (when used with a positioner) of Norriseal angle-disc butterfly valves and other types of quarter-turn valves.

Series 2G actuators can be configured with spring-return (“fail-safe”) operation or with a double-acting diaphragm for low-pressure applications.

Available in four size ranges with torque output to 17,000 in. lbs. The field-proven design easily adapts to various mounting styles and shaft types. A wide range of accessories is available, including electric and pneumatic positioners and limit switches.

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  • Spring-return or double-acting
  • Spring Rotation from clockwise to counter-clockwise is field-reversible
  • Easily adapted to various mounting styles and shaft types
  • Can be actuated with as little as 10 psig supply air
  • Adaptable to water or oil as the supply source
  • Wide range of switches, positioners and other accessories can be mounted


  • Actuates with as little as 10 psig supply air
  • Precise control when used with positioners, switches, solenoids or other available accessories
  • Operates using air, natural gas, nitrogen or other readily available gases
  • Optional fail-safe operation:
    (1) with spring-return models or
    (2) pressure-balanced units equipped with reserve air
  • Rugged, weatherproof construction includes totally enclosed gear and rack, as well as gear case seals to protect moving parts from corrosion
  • Closed yoke to protect the diaphragm stem from corrosive atmospheres

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