I. Basic Testing Methods
Audio Inspection: With the system stopped, listen closely to the piping for a hissing sound; this is the most direct sign of a leak.
Tactile Inspection: Touch the pipe joints and valve body. If you feel an airflow impact or an abnormal temperature increase, a leak is possible.
II. Professional Tool Testing
Pressure Gauge Measurement: Connect a pressure gauge to the cylinder port. After the engine is warm, fully open the throttle and start the engine for 2 seconds, then read the stable value. If the pressure value is lower than the standard value (e.g., ≥246 kPa for domestic engines), a leak may exist.
Leakage Rate Measuring Instrument: Directly measure the leakage rate. A reading exceeding 30%-40% requires repair.
III. Logical Reasoning Analysis
Trial and Error Method: Temporarily stop a part of the pneumatic system and observe if the fault disappears. For example, if the valve-controlled cylinder is not operating, remove the external load. If the cylinder operates after removing the external load, the leak may be due to excessive load.
Comparative Method: Replace suspected faulty components with standard components and compare their operating conditions to determine if failure has occurred.
IV. Experience Method:
Observation: Observe the actuator's movement speed, pressure gauge reading, lubricating oil quality, condensate drainage, whether the air at the reversing valve's exhaust port is clean, whether the solenoid valve indicator light is normal, whether pipe joints are loose, whether pipes are twisted or flattened, and whether there is obvious vibration.
Smell: Listen for abnormal sounds when the cylinder and reversing valve switch; smell for any special odors from overheating emitted by the solenoid coil and sealing ring.
Question: Review technical files, product samples, and daily maintenance records; interview on-site operators to understand the situation before and after the failure.
Touch: Touch the temperature of the external parts of moving components, the temperature rise at the solenoid coil, etc. If it feels hot to the touch after 2 seconds, investigate the cause; check for vibration in the cylinder and pipes, whether the piston rod has a creeping feel, and whether there are any leaks at joints and components.
V. Safety and Maintenance:
Ensure the equipment is shut down before testing to avoid high-pressure risks. Keep hoses away from heat sources and regularly inspect pipe supports.
Solenoid valve testing must be performed under normal control of the electronic control system.
VI. Common Causes of Failure
Seal Damage: Deformed sealing rings, excessive compression, or poor lubrication.
Foreign Object Jamming: Foreign objects are jammed in the valve core or piston rod.
Component Aging: Broken springs, rusted cylinders, incorrect pipe connections, etc.
Installation Problems: Piston rod stuck to end cap, loose electrical connectors, poor lubrication, etc.
VII. Quick Troubleshooting Steps
First Check for Leaks: Use hearing or touch to initially determine the location of leaks.
Next Check the Pressure: Use a pressure gauge to measure the pressure value and determine if it is below the standard value.
Finally Check Components: Replace suspected faulty components using a comparative method to confirm if they have failed.
VIII. Precautions
Prioritize checking common causes: such as damaged seals, foreign object jamming, etc.
Check components that were adjusted or replaced before the failure occurred first.
We will analyze each aspect step by step, from simple to complex, from easy to difficult, and from superficial to profound.
