The ZHA/B series pneumatic diaphragm actuator is a terminal execution unit used in industrial process control systems to drive linear valves such as globe valves and cage valves. It utilizes a flexible diaphragm to convert signal air pressure into mechanical thrust. The ZHA model (direct action) extends the stem when air pressure increases, while the ZHB model (reverse action) retracts the stem. Due to its simple construction, high reliability, and rapid response, the series is widely used in petroleum, chemical, power, and metallurgical industries. Its inherent safety makes it suitable for hazardous environments where electrical sparks must be avoided.

Product Image of ZHA/B Pneumatic Diaphragm Actuator

1.High sensitivity and linearity:Precision-designed springs and high-quality diaphragms ensure a strict proportional relationship between input air pressure and output stroke, providing accurate control.
2.Compact and lightweight design:Utilizing multi-spring or single-spring structures with pressed steel housings, the actuator is significantly lighter and smaller than traditional designs, reducing pipeline load.
3.Fail-safe safety logic:The actuator can be easily configured for air-to-open or air-to-close modes, ensuring the valve returns to a safe position via spring force during air supply failure.
4.Intrinsically safe attributes:Driven entirely by compressed air without electrical components, it is naturally explosion-proof and suitable for high-risk hazardous zones.
5.Durable material system:The housing surface is treated with anti-corrosion coating, and the diaphragm is made of reinforced synthetic rubber, offering excellent fatigue resistance and long service life.
6.High thrust output:Optimized diaphragm effective area and spring rates provide sufficient force to overcome stem friction and unbalanced medium forces.
7.Standardized mounting interface:Complies with international mounting standards (such as NAMUR), facilitating easy integration with various valve bodies and auxiliary devices like positioners.
8.Simple maintenance and low cost:Few moving parts and a modular design allow for rapid replacement of the diaphragm or springs without specialized tools, lowering lifecycle expenses.

Structural Drawing of ZHA/B Pneumatic Diaphragm Actuator

List of Component Names and Materials

Main Technical Parameters

Outline dimension table