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Diaphragm Actuator

image of Diaphragm Actuator


The PROVAL diaphragm actuator spring opposed diaphragm actuator provides precise, high thrust performance in a lightweight, compact format. The diaphragm actuators are designed afresh applying multi-spring type, so that these actuators are materialized to be miniaturized and light weighted as a new style. The PROVAL diaphragm actuators provide the operation to control the valve travel balancing between the force on the diaphragm by the signal air pressure, and the spring force.

By combining PROVAL positioner, the series brings about high accuracy of positioning.



· Low overall height
Design of leg posts and diaphragm casing allows for maximum strength with minimum overall height.
· Long service lift
Diaphragm casing are rugged, thick-walled, internally coated steel construction providing stability and corrosion protection.
· High trust capability
Molded and reinforced diaphragm permits higher pressure to provide maximum thrust for a given diaphragm size.
· High dynamic stability and frequency response
Shallow casing means reduced volume, thereby minimizing response time.
· Reduced hysteresis
Multi-spring design provides diaphragm stability and improves operational repeatability.


Type Single acting (Multi-spring)
Action Reverse action (RA), Direct action (DA)
Actuator Model A-270M A-360M A-430M A-520M
Effective Diaphragm Area(cm²) 310 630 970 1320
Max. Stroke (mm) 30 40 60 100
Materials Case SS (press)
Diaphragm ※EPDM
Shaft (output rod) SUS304 (H.Cr plated)
Yoke A216-WCB
Supply Air Pressure
kPa (kgf/cm²G)
160 (1.6), 240 (2.4), 320 (3.2)
Spring Range
kPa (kgf/cm²G)
20~98 (0.2~1.0), 80~240 (0.8~2.4), 120~240 (1.2~2.4)
Air Connection Rc 1/4 Rc 3/8”
Ambient Temperature -20°C ~ 80°C
Additional Options Mechanisms Top-mounted H/W, Side worm-mounted H/W, Travel stopper.
Accessories E/P Positioner, P/P Positioner, Air set, Limit S/W,
Solenoid valve, Booster relay, Speed controller, Lock-up valve, etc.

(1) ※: Manufactured and attached as according to customer’s order.
(2) Please consent in advance that approval drawing and other documents may represent with old material designation.
(3) For ambient temperature, denoted the extended temperature range as option.