Operational Mechanism
The air pressure inserted into the cylinder pushes out the piston wing and energizes its movement to rotate the scotch-yoke counter-clockwise, pressing the spring. Scotch-yoke converts the linear motion of the piston rod into a counter-motion rotation of the driving shaft 90, to open or close the valve, following the preset mode. When the air is discharged into the atmosphere via the solenoid valve, the spring force pushes the piston in reverse direction, and scotch -yoke enables clockwise rotation of the shaft to in reverse operate the valve. Air failure will cause the valve to return to its original open or closed position automatically, following a preset mode, unlike the valve actuated by Type B. The BSW actuator is driven by the same mechanism as the BS type, but is equipped with a handwheel for manual operation. Please note that the handwheel must be installed in the factory.