Introduction

Pneumatic actuators are mostly "quiet" equipment: once installed, supplied with air and moving normally, few people give them another look. But the real hidden dangers on site — insufficient pressure, a dented air line, loosened connections, a positioner coming loose — almost never "raise an alarm" in advance. For an actuator to stay stable over the long term, there is only one way: turn inspection into a system and make it routine. This article breaks the inspection items into two levels, "daily + monthly", and provides a quick-reference table and a practical procedure.

1. Why an Inspection System Should Be Established

  • Find hidden dangers early: air supply pressure drift, aging air lines and loosened bolts all develop gradually, and regular inspection can catch them before they become faults

  • Avoid unplanned downtime: pneumatic valves are mostly used in critical positions such as shut-off, isolation and control, and one unexpected downtime often drags down an entire unit

  • Extend service life: seal wear, corrosion and uneven wear of connections, if handled in time, can save the replacement cost of an entire actuator

2. Daily Patrol: 5 Must-Check Items

  1. Whether the air supply pressure meets the operating conditions: compare against the valve's required actuation torque and the actuator's rated air pressure (generally 0.4–0.7MPa); low pressure shows up directly as "slow action" and "won't close tightly"

  2. Whether there is obvious external damage: whether the cylinder body and end caps have impact cracks, and whether the coating has rust or peeling, paying special attention to outdoor and corrosive-medium applications

  3. Whether the air line has dents or aging: an air line pinched flat or with an aged, peeling inner wall restricts flow — the speed killer that is easiest to overlook

  4. Whether the assembly is firm: whether the bracket bolts, connecting shaft and air supply fittings are loose, and whether there are traces of leakage

  5. Whether there is abnormal noise or external leakage: fittings can be checked for leaks by brushing on soapy water; a clear cross-flow noise during action requires an immediate stop and troubleshooting

3. Monthly Special Inspection: Connections Are the Focus

Connections are the "joints" between the actuator and the valve, and also the high-incidence area for coming loose and uneven wear; a dedicated monthly special inspection is recommended:

  • The plane formed by the connecting rod and the connecting screw should be perpendicular to the horizontal plane — this is the item most easily overlooked during installation and inspection, and a wrong angle causes uneven wear and inaccurate travel

  • Whether the connecting pin and connecting shaft have excessive clearance or wear, and whether the coupling area has deflection

  • Whether the positioner, limit switch and solenoid valve are reliably connected to the actuator, with a special check for the hidden danger of "the positioner coming loose"

  • Whether the bracket and flange bolts are re-tightened to the torque requirement, with anti-loosening marks applied

4. Inspection Items Quick-Reference Table

Inspection item Recommended interval Acceptance criteria Handling of abnormalities
Air supply pressure Daily/each shift Within the actuator's rated range Adjust the pressure, and check the air supply and piping for leaks
Appearance and coating Weekly No cracks, no rust or peeling Touch up the paint, and evaluate replacement for severe corrosion
Air line Weekly No dents, no aging, no leakage Replace with an air line of the same specification
Assembly tightness Weekly Bolts tightened, nothing loose Re-tighten to torque and apply anti-loosening measures
Connections Monthly The connecting-rod plane is perpendicular to the horizontal plane Realign and replace worn parts
Accessory connections Monthly The positioner, etc. are not loose and signals are normal Refasten and calibrate the signals
Sealing and action Quarterly No external leakage, full travel to position Replace seals and adjust the limit

5. Four Steps to Put the System into Practice

  1. Set the standard: write down clearly for each item "what to check, the acceptance criteria, who checks it, and how often it is checked"

  2. Assign people and zones: divide responsibility by unit area, draw dedicated technical staff to cover sections, and inspect each actuator one by one against the content list every month

  3. Closed-loop rectification: register problems found in a file, specify the rectification plan, responsible person and rectification deadline, and carry out a re-inspection and sign-off after completion

  4. Link to assessment: include the execution of inspections and the rectification results in assessment, so that there is inspection, reward and penalty, and improvement

6. Recommended Fields for Inspection Records

Field Description
Date / unit tag number Convenient for traceability and statistical analysis
Inspector Responsibility is assigned to a person
Measured air supply pressure value The trend is more valuable than a single point value
Conclusion on appearance / connections Pass, observe, or fail
Problems found and rectification deadline Linked to the rectification closed loop
Re-inspection result The basis for sign-off

Conclusion

The reliability of a pneumatic actuator is half due to selection and installation, and half due to patrol inspection and systems. Look at five things daily (air pressure, appearance, air line, tightness, leakage), check one focus monthly (connections), and add responsible persons, rectification deadlines and re-inspection sign-off — then hidden dangers have nowhere to hide. For technical support on actuator inspection plans, please contact our service team.

Zhejiang Huaershi Auto-control Instrument Valve Co., Ltd.

Since 1989 · 30+ years focused on pneumatic actuators and pneumatic valves

Website: www.hesvalve.com