For the actuators with pneumatic diaphragms or air cylinders the matching flame-proof type electric-gas valve positioner shall be provided together with the valve.

Original control principle of hydraulic and electric system have been changed in de-sign of equipment to avoid defects such as folding, burning etc produced in upsetting of large air valve preform.

The test result shows electric expansion valve can improve the adjusting control level of automotive air conditioning and act as an electric magnetic valve as well.