What is the difference between single action and double action of pneumatic valve?

The opening and closing actions of double-acting cylinders are all driven by air source; Turn on ventilation, turn off ventilation, stop breathing and stay in place; ? The action of single-acting switch is only that the opening action is driven by air source, while the closing action is spring-reset.

2. Type

Single action: normally open type and normally closed type.

Normally open type: ventilation off, gas off; Normally closed type: ventilation is on and gas is off.

3. Function

Single action is simpler than double action. For example, double action can connect three-position five-way middle seal and medium voltage to realize safety function, but single action can't realize this function.

4. Working principle

Double action: When the air pressure enters the middle cavity between the two pistons of the cylinder from the air hole, the two pistons separate and move to the two ends of the cylinder, and the air in the air cavities at both ends is exhausted through the air hole, and at the same time, the two piston holders synchronously drive the output shaft (gear) to rotate counterclockwise.

Single action: When the air pressure enters the middle cavity between the two pistons of the cylinder from the air port, the two pistons separate and move to the two ends of the cylinder, forcing the springs at both ends to compress, and the air in the air cavities at both ends is exhausted through the air port, and at the same time, the two piston holders synchronously drive the output shaft (gear) to rotate counterclockwise.