Operation Methods and Precautions for Hydraulic Cylinder

Suitable for hydraulic parts foreign trade manual, product brochure, technical document

Table of Contents

1. Pre-operation Inspection

2. Standard Operation Procedures

3. Key Precautions during Operation

4. Maintenance & Storage Requirements

5. Troubleshooting Reminders

6. Glossary

1. Pre-operation Inspection

Before starting the hydraulic system, complete a full inspection of the hydraulic cylinder and related piping.

1. Check the cylinder barrel, piston rod, flanges and pipe joints. Confirm no deformation, cracks, dents or external oil leakage. The chrome-plated surface of piston rod shall be free of scratches, corrosion and burrs.

2. Verify all mounting bolts, pin shafts and pipe fittings are tightened firmly. The cylinder mounting base must have sufficient rigidity to avoid bending under load.

3. Check hydraulic oil level, oil color and cleanliness. Confirm oil viscosity, oil temperature and oil grade comply with design requirements.

4. Check alignment: the center line of the cylinder must coincide with the direction of load force. Avoid lateral force which will wear seals and bend piston rod.

5. For cylinders fitted with air vent plugs, open the air vent before initial commissioning to discharge trapped air inside the cylinder. Air inside will cause jerking movement, vibration and cavitation.

2. Standard Operation Procedures

1. No-load running: Start the hydraulic system and run the cylinder at no load for 3–5 cycles. Extend and retract the piston rod fully at low speed. Confirm smooth movement without sticking, jitter or abnormal noise. Fully discharge air inside the cylinder during this stage.

2. Load commissioning: Gradually increase working pressure to rated pressure. Do not reach full load instantly. Observe cylinder action, pressure reading and sealing status.

3. Normal operation: Control extension and retraction speed steadily. Avoid sharp acceleration, emergency stop and frequent rapid reversing. Slow down before the piston reaches stroke end to reduce hydraulic impact.

4. Stop operation: After work, retract the piston rod to the fully retracted position if possible. Shut down the hydraulic pump and release system pressure. Do not keep the cylinder under sustained pressure for long idle periods.

3. Key Precautions during Operation

1. Never overload or overpressure. Working pressure cannot exceed the rated pressure marked on the cylinder nameplate. Sustained overpressure will cause barrel expansion, piston rod bending, seal failure and even cylinder burst.

2. Strictly prevent lateral load. The hydraulic cylinder is designed to bear axial load only. Side force scratches piston rod, damages seals and causes permanent bending of piston rod.

3. Do not continue pressurizing after the piston hits the stroke end. The impact pressure will damage cylinder bottom, thread and sealing components. Use buffer function or flow control to decelerate near stroke limit.

4. Keep the piston rod surface clean. Dust, sand, welding slag and metal chips will damage the dust seal and main oil seal. Install protective dust cover for dusty, muddy or corrosive working environment.

5. Keep oil temperature within the allowable range, normally 20℃～80℃. Too high oil temperature accelerates seal aging; too low viscosity leads to poor lubrication and unstable movement.

6. Keep hands and body away from the squeezing area between piston rod and cylinder head during operation. Never disassemble cylinder, tighten fittings or adjust pipeline while the system is pressurized.

7. Prevent external impact. Do not strike cylinder barrel and piston rod with heavy tools. Any dent or scratch on piston rod will quickly cause continuous oil leakage.

4. Maintenance & Storage Requirements

1. Hydraulic oil and filter element shall be replaced periodically. Contaminated oil is the main cause of internal wear, scoring and internal leakage of hydraulic cylinder.

2. Regularly check static and dynamic sealing parts. Replace aging, hardened or cracked seals in time.

3. For long-term storage, retract piston rod completely, coat anti-rust grease on exposed rod surface, seal oil ports, and store in dry environment. Do not store the cylinder with piston rod extended.

4. Regularly check mounting pins, hinges and brackets for wear and looseness. Re-align if offset occurs.

5. When disassembling the cylinder, keep all parts clean. Do not scratch inner surface of cylinder barrel, piston and piston rod. Use new seals during reassembly.

5. Troubleshooting Reminders

• Jerking or creeping action: Mostly caused by trapped air, poor lubrication or oil contamination.

• External oil leakage: Usually damaged dust seal, rod seal or loose pipe joint.

• Internal leakage and insufficient thrust: Worn piston seal, scoring inside cylinder barrel.

• Abnormal noise and vibration: Air in system, loose mounting or misalignment of load.