Ledeen Quarter Turn Actuators

All Ledeen 'T' and 'Q' Series actuators employ the scotch-yoke principle for converting linear force into torque. The scotch-yoke mechanism is manufactured as the "Tandem" or 'T' Series unit with a single torque arm and one or two cylinder configuration and for larger valves the "Quad" or 'Q' series unit, with a double torque arm and four cylinder configuration.

The scotch-yoke principle is particularly well suited for the operation of ball, plug and butterfly valves .in that the maximum torque output is at the beginning and end of stroke. This distribution of effort matches the characteristic of these types of valves, where the highest torque is required for seating and unseating.

The 'T' and 'Q' Series units employ stroke adjustment, to allow accurate valve port and seat alignment, as well as speed control and torque limiting. The actuator stroke is controlled by limit switches in the case of electric control via solenoid valve or local push button; by limit valves when the unit is controlled from a pneumatic signal. The explosion proof switch pack unit contains up to 10 SPDT switch elements, and can be equipped to give position feedback. Manual operation for the direct pneumatic units can be by wrench, jack screw, or gearbox and for all other hydraulic units by hand pump. All quarter turn actuators can be supplied as DOUBLE ACTING or as SPRING RETURN.