The actuators of pneumatic ball valves are mainly divided into two types: single acting pneumatic actuators and double acting pneumatic actuators. The specific introduction is as follows:

1. Single acting pneumatic actuator

Working principle: The cylinder is equipped with a reset spring, and the air source pressure enters the cylinder through an electromagnetic valve to push the piston to move, while compressing the spring to store energy. After the solenoid valve releases the cylinder pressure, the spring pushes the piston to reset, driving the ball valve core to automatically reset and maintain an open or closed state.

characteristic:

In case of gas source failure or no pressure, it can automatically reset to a safe state.

Suitable for working conditions with strict safety requirements for switch status.

The manual switch mechanism has a large torque and needs to overcome the spring thrust.

Application scenario: In situations where it is necessary to ensure that the valve maintains a specific state in the event of a gas source failure, such as emergency shutdown systems.

2. Double acting pneumatic actuator

Working principle: There is no reset spring in the cylinder, and the supply direction is switched by an electromagnetic valve to achieve reciprocating motion of the cylinder, driving the ball valve to open or close.

characteristic:

Continuous gas supply is required to maintain the valve status, and it cannot automatically reset when the gas source fails.

Low cost and smaller cylinder diameter.

The output torque remains constant and increases with the increase of gas source pressure.

Application scenario: Normal working conditions where there is no automatic reset requirement for valve status and the gas source is stable.

Additional classifications for actuators

According to the structural form:

Piston type: suitable for large caliber, high pressure drop control, with high output force.

Thin film type: suitable for small output, high-precision control, simple structure, and cheap price.

Gear rack type: compact structure, fast response, long service life, suitable for harsh working conditions.

Fork type: Large caliber valve with high output torque and reasonable structure.

By function:

Two position: Only implement control for opening and closing.

Proportional: Continuous adjustment of flow or pressure is achieved through a valve positioner.

Key points for actuator selection

Torque matching: Valve torque, medium pressure, and safety margin need to be considered.

Action speed: Single acting reset takes longer, double acting response is faster.

Reliability: Single acting is safer in the event of gas source failure, while double acting is more cost-effective.

Maintainability: Single acting springs require regular inspection, while double acting structures are relatively simple.

The selection of pneumatic ball valve actuators should be comprehensively considered based on working conditions, safety requirements, and cost budget.