hongxiangping
Mechanical
thread794-171508
I need some advice on interpretation of thickness calculations for 2:1 ellipsoidal head, as per ASME BPVC Sect I, PG 29.
As per PG-29.1, it states that minimum blank dished head thickness shall be t=5PL/4.8Sw. As per PG-29.7, it states thickness of blank 2:1 ellipsoidal head shall be at least that calculated for shell as per PG-27.
Q1: When come to 2:1 ellipsoidal head, should I just follow PG-29.7, or need to take the highest thickness calculated following PG-29.1 and PG-29.7? I have seen both methods used by different parties, can anyone advise which is correct?
Q2: From my own experience in calculation exercise, PG-29.1 will generally result in significantly higher thickness as compared to PG-29.7. This means the head will be thicker compared to the shell. Can anyone offer some explanation on why is that so? If referring to ASME BPVC Sect VIII-1, UG-32, same for formed heads, it is common that a blank head should result in lower thickness as compared to the shell. Anyone can explain why there is such difference between Sect I and Sect VIII-1? What is the logic behind this?
Appreciated if anyone can help. Thanks a lot!
I need some advice on interpretation of thickness calculations for 2:1 ellipsoidal head, as per ASME BPVC Sect I, PG 29.
As per PG-29.1, it states that minimum blank dished head thickness shall be t=5PL/4.8Sw. As per PG-29.7, it states thickness of blank 2:1 ellipsoidal head shall be at least that calculated for shell as per PG-27.
Q1: When come to 2:1 ellipsoidal head, should I just follow PG-29.7, or need to take the highest thickness calculated following PG-29.1 and PG-29.7? I have seen both methods used by different parties, can anyone advise which is correct?
Q2: From my own experience in calculation exercise, PG-29.1 will generally result in significantly higher thickness as compared to PG-29.7. This means the head will be thicker compared to the shell. Can anyone offer some explanation on why is that so? If referring to ASME BPVC Sect VIII-1, UG-32, same for formed heads, it is common that a blank head should result in lower thickness as compared to the shell. Anyone can explain why there is such difference between Sect I and Sect VIII-1? What is the logic behind this?
Appreciated if anyone can help. Thanks a lot!
