Power Cylinder

Power Cylinder :

Power Cylinder are widely used for accurately and positively. Positioning all types of plant regulators such as Dampers, ID, and FD. Fans in Boilers, Throttle Valves, and Butterfly Valves. This cylinder can be arranged so that increase or decrease in control pressure moves the position either outwards or inward.

Principle Of Operation :

The position-control unit (D/A VP) incorporated in the power cylinder receives a control signal (0.2 to 1.0 kg/cm2) from a controller and regulates the high-pressure air supply to the cylinder to give a corresponding displacement of the cylinderposition. The position-control unit operates on the force-balance principle and comprises a diaphragm to receive the control signal, a control spring, one end of which is moved by the piston rod through a cam and bell crank, and a pilot valve to admit and exhaust the high-pressure athe cylinder. When the control signal changes, the diaphragm expands or contracts to open the pilot valve and admitting air to the cylinder to move the piston, any force on the pistonless than the designed maximum thrust of the power cylinder will not prevent movement as the pilot valve remains open until the restraining force is overcome and the position requirements are met. The change in the pistons position causes the control-spring force to increase or decrease until a state of equilibrium is reached between the opposing forces of the diaphragm and control spring, the pilot valve is then closed and the piston comes to rest in its new position.