1. Verify Material Certification Documents
Tube Material: High-quality boiler steel tubes (e.g., GB3087 standard) with good high-temperature resistance, pressure resistance, and heat transfer performance should be used. A complete material certificate or third-party testing report from the manufacturer is required.
Corrosion Resistance: For use in food, pharmaceutical, or chloride-containing environments, 316L stainless steel (containing molybdenum, improving corrosion resistance by 4-5 times) must be used. Avoid using ordinary 304 stainless steel, which can lead to stress corrosion cracking.
Surface Roughness: The Ra value of the inner wall of sanitary equipment should be ≤0.4μm to prevent bacterial growth and material residue. This can be verified through on-site sampling with a surface roughness meter.
2. Check Key Structural Parameters
Cylinder Wall Thickness: The wall thickness of qualified equipment should be 12-18 mm, possessing wear and corrosion resistance properties to withstand long-term operational wear.
Expansion Joint Process: The tube bundle should be joined using an expansion joint process instead of welding to eliminate rotational alternating stress, prevent weld fatigue cracking, and extend equipment life.
Coaxiality Control: The half-shafts at both ends of the tube bundle need to be machined integrally to ensure coaxiality, reduce operating vibration, and improve the life of the main bearing.
3. On-site Inspection and Auxiliary Verification: Use a spectrometer to analyze the composition of metal components to confirm compliance with the nominal grade (e.g., 316L, GB3087, etc.).
Randomly check welds or expansion joints for defects such as cracks and porosity; perform non-destructive testing (e.g., ultrasonic testing) if necessary.
Check whether steam heads, seals, and other leak-prone parts are made of high-temperature and pressure-resistant materials to prevent leaks during operation.
4. Indirect Judgment of Operational Performance: Equipment made of qualified materials should exhibit no significant vibration, abnormal noise, or leakage during continuous operation, with axial movement < 0.05mm.
The stable steam consumption and low dust concentration in the exhaust gas (<20mg/m³) reflect a good match between the material and the structure.
