The actuator is a double-piston actuator, specially designed for operating ball valves and flaps. Two versions are available: double-acting and spring return (single-acting). The double piston design allows high torque with small external dimensions. You can adjust the angular stroke by ± 6 ° with the standard end position. Design The force from the reciprocating pistons is transmitted to a pinion by two racks attached to the pistons. This arrangement delivers a linear torque characteristic across the full stroke. Principle of operation double-acting The space between both pistons is pressurized through point 'A' - forcing the pistons apart. The force of both pistons is transmitted through the racks to the pinion 'C'. When pressure is applied at connection 'B', and 'A' is vented, both external chambers are pressurized and the pistons are forced together. You can set the angular stroke by undoing lock nuts 'E' and adjusting the final stroke position setting screws 'D'. Principle of operation single-acting The space between both pistons is pressurized through point 'A' - forcing the pistons apart and forcing the springs together. The force of both pistons is transmitted through the racks to the pinion 'C'. If no pressure is applied at connection 'B', and 'A' is vented, the pistons are forced to their home positions by the spring resistance. You can set the angular stroke by undoing lock nuts 'E' and adjusting the final stroke position setting screws 'D'.