Simple pressure vessels are not produced in batches
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RT: Our company wants to produce several gas storage tanks with a capacity of 1 cubic meter at 0.8 MPa； Logically, it would be appropriate to produce in large batches due to the large volume, but we are not specialized in manufacturing gas storage tanks, and there would be no market for such products once they are made. So for small-scale production, should we: 1. Use GB/T150 for the design of the drawings? 2. Conduct non-destructive testing on each unit instead of only sampling? 3. Skip conducting type tests (since there is no batch formation)? There are also a few other questions: 1. If design follows GB/T150, does the user still need to submit it for inspection and registration? 2. Can we still only provide the user with copies of the drawings? (PS: Our company doesn’t have design capabilities and can only purchase existing drawings; this has a significant impact on the cost of small storage tanks.) 3. Is it necessary to retest the plates made of Q235B? (Noting that many manufacturers specializing in gas storage tanks are still using Q235B.) 4. Is it appropriate to use permanent gaskets, necked ends, or TIG welding for the base layer in constructing the head and cylinder? There are quite a few questions; please help answer them, thanks! !
I’ll handle it myself; those who know the answer, please help me out. Thanks!
Since it is not treated as a simple pressure vessel, all the relaxed requirements applicable only to simple pressure vessels must be removed, and the standard requirements for pressure vessels shall be followed
The as-built drawings must be provided to the user with a valid design seal affixed to them
The special inspection agency here says it can be treated as a simple pressure vessel according to the relevant regulations, but in reality it must be designed in accordance with GB150. What they really mean is that radiographic testing and similar procedures cannot be carried out on a sample basis; testing must be done on each unit, just like in the case of batch processing. I took a look at Appendix A2 of the major specifications (page P103); it seems that no registration is required. However, there are doubts regarding the drawings, and I’m not sure if a copy can be provided
For non-simple pressure vessels required by major regulatory standards, official drawings must be provided on a per-unit basis
If simple containers are not used, then they must be submitted for inspection in accordance with the regulations for regular pressure vessels, which entails stricter requirements. 1. It needs to be inspected and registered. 2. The drawings must have the design red stamp. 3. Use Q235B plates; refer to Appendix 150.3 for re-inspection requirements, minimum temperature limits, etc., and the thickness should not exceed the specified limits. 4. For welding the head and cylinder, using gaskets represents the simplest form of single-sided welding; TIG welding as a backing process is equivalent to double-sided welding. Of course, double-sided welding yields better quality when conditions permit, depending on the coordination between design and manufacturing teams. The B seam is not taken into account, and its weld coefficient is also of little use. As for necking, I haven’t worked with it before.
Refer to Appendix A2 of the major code: those produced in small quantities should be designed in accordance with GB150, but their management is the same as that for batch production (since they are essentially simple containers and the manufacturing process is stricter than that for batch production, the probability of problems occurring should be lower than in batch production); in other words, there is no need for inspection or registration. The information available is conflicting; of course, it’s safer to provide them with the stamped version, but surely we can save some money by using simple containers and providing copies instead. . .
Are there experts in gas storage tanks? Bulk-produced gas storage tanks do not use TIG welding for the root pass, probably due to low efficiency. But could there be problems with poor adhesion of the permanent shims?