Ask questions: NB/T47020 there is such a word “ cylinder is connected with the neck flange thickness shall not be less than NB/T47023 in the provisions of the minimum thickness and docking cylinder, cylinder length not less than (DN* thickness) square root ” now, equipment is directly with the head neck flange butt. Then head straight edge length to meet this requirement.
If the cylinder body and the flange butt, consider the length, but the head of the straight section here, we did not consider, or your head straight section too long, non-standard manufacturing will be ma
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