RTO (Run-to-Close Torque)
The torque required to continue rotating a valve from partway open toward the fully closed position. Usually less than BTO. The actuator must sustain RTO throughout the entire stroke, not just at the seat.
What is RTO (Run-to-Close Torque)?
The torque required to continue rotating a valve from partway open toward the fully closed position. Usually less than BTO
Vajra Industrial Solutions is an engineering-driven industrial valve manufacturer and supplier. Concepts such as rto (run-to-close torque) inform how we select, manufacture, and document valves for industrial service.
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What is a RTO (Run-to-Close Torque)?
The torque required to continue rotating a valve from partway open toward the fully closed position. Usually less than BTO. The actuator must sustain RTO throughout the entire stroke, not just at the seat.
How is a RTO (Run-to-Close Torque) sized for a valve?
Actuator sizing requires the valve's breakaway torque (BTO), running torque (RTO), and end-to-close torque (ETO) at the maximum differential pressure and operating temperature. The actuator output torque at minimum supply pressure must exceed the valve BTO by a safety factor (typically 1.25x minimum). For pneumatic actuators, the supply pressure range, fail-safe direction (spring return FC or FO), and speed requirements must also be specified.
When is a RTO (Run-to-Close Torque) required versus manual operation?
Automation is required when: (1) the valve is in a remote or hazardous location, (2) rapid opening/closing is needed for emergency shutdown (ESD), (3) the valve must respond to a control signal (4–20 mA, HART, or fieldbus), (4) the operating torque is too high for manual operation, or (5) the valve is part of a Safety Instrumented System (SIS) requiring SIL certification. Contact Vajra Industrial Solutions for fully automated valve packages including actuator, limit switch, solenoid, and positioner.
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