What items are included in the regular inspection of pressure vessels?

1. Macro inspection
Appearance inspection: Check the appearance of the pressure vessel, including welds, flanges, valves and other parts, and check for defects such as cracks, deformation, corrosion, etc.
Structural inspection: Check the structure of the pressure vessel, including the connection between the cylinder and the head, manholes, inspection holes and their reinforcement, corner joints, overlaps, and unreasonable welds.
Geometric dimension inspection: Check the geometric dimensions of the pressure vessel, including the misalignment of the longitudinal and circumferential welds, the angle of the edges, the weld excess height, the weld thickness of the fillet welds and the size of the weld angle, etc.
2. Wall thickness measurement
Thickness measurement position selection: Select representative positions for wall thickness measurement, including parts where the liquid level often fluctuates, parts that are prone to corrosion and erosion, parts where the wall thickness is thinned during manufacturing and parts where deformation occurs during use, etc.
Thickness measurement method: Usually an ultrasonic thickness gauge is used for wall thickness measurement. If there are interlayer defects in the parent material, additional measurement points should be added or an ultrasonic flaw detector should be used to find out the distribution of the interlayer.
3. Surface defect detection
Corrosion and mechanical damage inspection: Determine the depth, diameter, length and distribution of corrosion and mechanical damage, and record them with a map.
Surface crack inspection: Check the welds on the inner surface (including the near-seam area), and check the cracks with the naked eye or a 5-10 times magnifying glass.
Weld undercut inspection: Check the weld undercut. For welding-sensitive materials, pay attention to check the possible weld toe cracks.
4. Buried defect detection
When necessary: ​​Radiographic flaw detection, ultrasonic flaw detection and other methods can be used to check the defects inside the pressure vessel as needed.
5. Safety accessory inspection
Safety accessories such as safety valves and pressure gauges: Check whether safety accessories such as safety valves and pressure gauges are within the validity period of calibration and verification, and provide calibration reports and verification certificates.
Safety protection devices: Check the operating status of safety protection devices to ensure that they are sensitive and reliable.
6. Other test items
Hardness measurement: Hardness measurement can be performed as needed.
Material analysis: Analyze the material to ensure that it meets the design requirements.
Pressure test: When necessary, pressure test shall be carried out to verify the sealing and strength of pressure vessels under the design pressure.
Air tightness test: For pressure vessels with extremely or highly hazardous medium toxicity or where no trace leakage is allowed in the design, air tightness test must be carried out.
Low temperature insulation performance test: For tank cars, railway tank cars and tank containers with vacuum insulation tank bodies, low temperature insulation performance test shall be carried out.
VII. Data review
Technical data: Review the technical data, use management data and inspection and examination data related to pressure vessels, including the annual inspection report within the regular inspection cycle and the regular inspection report of the previous year.
Safety accessories and instrument calibration report: Provide the calibration report and calibration certificate of safety accessories and instruments within the validity period of calibration and verification.
VIII. Correction confirmation
Correction notice: After the inspection, the inspector will issue the "Special Equipment Supervision Inspection Opinion Notice" or "Special Equipment Periodic Inspection Opinion Notice" to put forward rectification opinions on the defects found.
Correction confirmation: The user unit shall make rectification according to the rectification opinions, and the inspection agency shall confirm it.