AP5.5

PNEUMATIC ROTARY ACTUATOR

AP SERIES

SPRING RETURN ACTUATOR (SR) ISO 5211

PRINCIPLE OF OPERATION

PRESSURE APPLIED TO PORT ‘A’ WILL CAUSE THE INNER CHAMBERS TO BE PRESSURISED, FORCING THE PISTONS OUTWARD TO COMPRESS THE SPRINGS.

THE PINION IS ROTATED COUTER COUNTEIL CLOCKWISE. UPON RELEASE OF PRESSURE THROUNG POR’A’ THE SPRINGS WILL EXERT PRESSURE TO CLOSE THE PINTONS AND ROTATED THE PINION CLOCKWISE RAPIDLY.

THIS ACTION WILL OFTEN BE USED TO CLOSE A90⁰ TURN VALVE IN SHUT-DOWN MODE.

SELECTION OF SPRING RETURN ACTUATOR (SR)

DETERMINE THE REQUIRED VALVE TORQUE, THIS SHOULD INCLUDE 25” SAFETY MARGIN, AND THE MINIMUM OPERATING PRESSURE AVAILABLE. SELECT FROM THE SPRING STROKE/ “0⁰” TABLE A VALUE THAT IS NOT LESS THAN THE REQUIRED VALVE TORQUE (INCLUDING SAFETY MARGIN). NEXT REFER TO THE PRESSURE GTABLE AND SELECT UNDER YOUR MINIMUM PRESSURE AND 90⁰ TORQUE COLUMN A FIGURE NOT LESS THAN THAT REQUIRED (INCLUDING SAFETY MARGIN).

EXAMPLE: VALUE TORQUE 60 Nm PLUS 25% = 75Nm CHECKING THE “SPRING STROKE / “0⁰” COLUMN, IT WILL BE NOTED THAT THE NEAREST VALUE IS 108 Nm.

BY FOLLOWING THE LINE ACROSS TO THE VERTICAL 5 BAR “90⁰” TORQUE COLUMN, A FIGURE OF 109 Nm IS SHOWN THEREFOR, THESUITABLE ACTUATOR IS THE “AP5SR5”. IN A NORMAL VALVE SHUT-DOWN SITUATION THE ACTUATOR  WOULD OPERATE THE VALVE TO BREAK OUT A LESS THAN108 Nm. IF THE 90⁰ TORQUE AT OPERATING PRESSURE IS TOO LOW. CONTINUE DOWN THE COLUMN UNTIL AN ACCEPTABLE VALUE IS FOUND, COMPARE WITH THE CORRESPONDING “SPRING PTROKE / “0⁰” COLUMN TO ENSURE THAT THIS ALSO IS ADEGUATE.THIS MODEL MAYBE USED.