Pneumatic actuators are mainly divided into three types: diaphragm type, piston type and gear rack type. Their structure and material selection directly affect performance and applicable scenarios.

1. Type difference
Diaphragm actuator: Use air pressure to push rubber/polytetrafluoroethylene film to generate thrust, simple structure, suitable for small thrust, high frequency adjustment (such as regulating valve).

Piston actuator: Adopt cylinder piston structure, large output force, fast action speed, suitable for high pressure, large diameter valves (such as cut-off valve).

Gear rack actuator: Drive the gear to rotate through air pressure to achieve 90° rotation movement, commonly used for the switch control of ball valves and butterfly valves.

2. Material difference
Housing: aluminum alloy (lightweight, rust-proof), stainless steel (corrosion-resistant, high pressure environment).

Seals: nitrile rubber (NBR, oil-resistant), fluororubber (FKM, high temperature/chemical corrosion resistant), polytetrafluoroethylene (PTFE, acid and alkali resistant).

Piston/gear: carbon steel (economical), stainless steel (high corrosion resistance), anodized aluminum (lightweight).

When selecting, it is necessary to combine the corrosiveness of the medium, temperature pressure and explosion-proof requirements to ensure reliability and long life.