Cylinder Periodic Inspection
Mandatory re-test line for cylinders.
What is Cylinder Periodic Inspection?
Cylinders (CNG, O₂, LPG, diving, industrial) must be periodically re-tested per regulation. The inspection line includes external visual check, hydrostatic re-test, valve leak test, drying and stamping.
Skipping periodic inspection is illegal — expired cylinders cannot be filled or transported. Failure risks explosion during fill or use.
Key terms: external inspection (visual check of surface), hydrostatic re-test (water pressure proof test), volumetric expansion (measured in water jacket — '外测法').
Manual vs Electric vs Air-Driven
Drive methods differ sharply in pressure limit, explosion safety, and automation.
| Drive Method | Pressure Limit | Explosion-Proof | Features |
|---|---|---|---|
| Manual pump | ~100 MPa | ✓ (no electricity) | Cheap / labor-intensive / no automation |
| Electric pump | ~300 MPa | Needs Ex motor | Automated / needs power / heat |
| Air-driven pump | ~600 MPa [TBC] | ✓ (pneumatic) | Safe / auto hold / no power |
For cylinder inspection lines, air-driven = complete + reliable + compliant.
SUNCENTER Equipment for This Process
Hydrostatic Test Machine (外测法)
Volumetric expansion measurement.
Valve Leak Test Bench
Cylinder valve tightness.
Cleaning & Drying Machine
Auto clean & dry after test.
Process Flow Diagram
Flow subject to technical-dept. confirmation
Receive & inspect
Visual check, record ID.
Clean
Remove oil & debris.
Hydro re-test
Pressurize, measure expansion.
Valve test
Valve leak check.
Dry & assemble
Dry interior, reassemble.
Stamp & release
Mark test date, release.
Typical Parameters
Values per product manual — for reference only.
| Workpiece | Test / Working Pressure | Recommended Model |
|---|---|---|
| CNG cylinders | 30-45MPa test | 外测法 hydro machine |
| O₂ cylinders | 22-30MPa test | 外测法 hydro machine |
| LPG cylinders | 2.1-3.2MPa test | Standard hydro bench |
Further Reading
Blog system under construction — titles below are planned.
- Cylinder inspection line: what equipment do you need?TBC
- 外测法 vs 内测法 hydro test: which is better?TBC
- Cylinder valve leak test common issuesTBC
Need Cylinder Periodic Inspection equipment?
Tell us your working conditions and target pressure — our engineers recommend the right model.