Products in every industry have corresponding technical standards. For critical equipment such as valves and pneumatic actuators, which affect industrial safety, strict compliance is especially important: only equipment that meets the standards can ensure trouble-free long-term operation.

Which technical standards apply to pneumatic actuators? This article introduces requirements for structure, performance and appearance.

1. Structural requirements

  • Basic components

A pneumatic device mainly consists of a cylinder, piston, pinion shaft, end caps, seals and screws. A complete pneumatic assembly should also include a position indicator, travel stops, solenoid valve, valve positioner, pneumatic components, manual mechanism and signal feedback components.

  • Mounting interface dimensions

The connection dimensions between pneumatic devices and valves should comply with ISO 5211 for the bottom mounting interface, as well as GB/T 12222 and GB/T 12223. This means actuators and valves from different manufacturers have standardized mounting interfaces and can be interchanged and matched.

  • Manual mechanism requirements

A pneumatic device with a manual mechanism should allow the valve to be opened and closed manually when the air supply is interrupted. When facing the handwheel, turning the handwheel or handle counterclockwise should open the valve, and clockwise should close it, consistent with the operating direction generally used in the valve industry.

  • Piston-rod wrench flats

Where the piston-rod end has an internal or external thread, it should have flats suitable for a standard wrench to facilitate installation and maintenance.

  • Seal replacement

Piston seals should be easy to replace and service, reducing maintenance difficulty and downtime.

  • Cushioning mechanism

For pneumatic devices with cushioning, the cushioning stroke length should meet the relevant standards. Adjustable cushioning devices should have an external adjustment mechanism on the cylinder body for convenient on-site commissioning.

  • Air inlet and outlet threads

Cylinder air-port thread dimensions should comply with the NAMUR accessory standard and GB/T 7306.1, GB/T 7306.2 and GB/T 7307, ensuring interface compatibility with solenoid valves and other accessories.

2. Performance requirements

  • Rated output force/torque

The rated output force or torque of a pneumatic device should comply with GB/T 12222 and GB/T 12223.

  • No-load operation

When specified air pressure is supplied to the cylinder without load, movement should be smooth, without sticking or stick-slip. This is a basic indicator of cylinder-bore machining precision and piston-seal quality.

  • Output force testing

At the standard air pressure of 0.6MPa, output torque or thrust in both opening and closing directions should be no less than the rated value on the nameplate. Motion should be smooth, without deformation or other abnormalities.

  • Leakage testing

Leakage testing is a key measure of pneumatic actuator quality. When tested at maximum operating pressure, air leakage from the backpressure side must not exceed (3+0.15D) cm³/min, and leakage from the end caps and output shaft must not exceed (3+0.15d) cm³/min, where D is cylinder diameter and d is output-shaft diameter, both in mm.

  • Strength testing

Conduct the strength test at 1.5 times the maximum operating pressure. After holding the test pressure for 3 minutes, no leakage or structural deformation is permitted at the cylinder end caps or static seals. This ensures actuator safety under extreme operating conditions.

  • Operating life

When simulating valve operation while retaining the required output torque or thrust in both directions, the pneumatic device should complete at least 50,000 cycles, with one opening and closing sequence counted as one cycle. This is a basic requirement for long-term reliability.

  • Cushioning performance

For pneumatic devices with cushioning, impact is not permitted when the piston reaches the end of its stroke, protecting the valve and piping system.

3. Appearance requirements

  • Casting quality

Cast cylinder end caps, end flanges and housings must be free of scratches, cuts, blowholes, burrs and other defects.

  • Surface treatment

External paint or chemical-treatment layers should be flat, smooth and uniform in color, without oil contamination, indentations or other mechanical damage.

4. Why do these standards matter?

Technical standards establish the minimum level of product quality and are an important basis for equipment selection. During procurement, pay attention to the following:

Check whether the product identifies its applicable manufacturing standards, such as GB/T 12222 and ISO 5211.

Confirm that leakage and strength test results meet the requirements.

Check whether the design cycle life meets the operating conditions.

Verify that mounting interface dimensions match the existing valve.

Understanding these standards helps you select and accept equipment with confidence and purchase products that meet quality requirements.

Zhejiang HES Automatic Instrument & Valve Co., Ltd.

Established in 1989 · Focused on pneumatic actuators for more than three decades

Products comply with domestic and international standards including ISO 5211, NAMUR and GB/T