Issue of wall thickness in short sections of Type B equipment flanges
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As is well known, for Type B equipment flanges, the length and thickness of the spool are specified; for example, in the case of DN800 with a weight of 16 kilograms, the spool thickness is 16 mm and its length is 200 mm. Can the wall thickness of this spool be changed? Can the length be changed? Is it necessary to follow his rules?
It can be changed; the detailed specifications are provided in the earlier technical requirements of the JB/T4700~4707 standards
Thickening or lengthening poses no problem. It just needs to be higher than the standard requirements. But it can’t be small.
It can be changed; once it is changed, calculations need to be done, and once those calculations are carried out, the flange thickness might need to be increased again
Changes can be made within the limits specified in JB/T4700; no calculation is required, as stated in 3.2 and 5.3.4 of JB/T4700
Note that the specified corrosion allowance is less than or equal to 2 mm; if it is 3 mm, the tube section must be thickened by 2 mm.
Since this length and thickness take into account the range of influence of local stresses at the flange-tube connection area as well as the need for reinforcement, it is necessary to make changes or increase the thickness and length in accordance with the standards; any reduction in these values requires a custom design.