Sawsan311
Chemical
- Jun 21, 2019
- 303
Dear All
reference to API 526 on relief valves orifice designations and flange ratings, the various tables provided for the different orifice sizes show that as the size increases from L to P,R, T etc the inlet flange rating size reduces for example, T PSV has a maximum flange rating of 300. API 526 refers to ASME B16.34 for the flange ratings.
I would like to understand the mechanical background behind the above, why larger PSVs tend to have lower limits for inlet flange rating.
Additionally, I can see that as the size of the PSV increases, for balanced spring loaded valves, the bellow pressure limits tend to reduce as well, I am sure this is relevant to ASME B16.34 but what is the physical behavior behind having the bellow pressure limit decreasing as the PSV sizes increase for example for D throughout T.
Appreciate your views
regards,
reference to API 526 on relief valves orifice designations and flange ratings, the various tables provided for the different orifice sizes show that as the size increases from L to P,R, T etc the inlet flange rating size reduces for example, T PSV has a maximum flange rating of 300. API 526 refers to ASME B16.34 for the flange ratings.
I would like to understand the mechanical background behind the above, why larger PSVs tend to have lower limits for inlet flange rating.
Additionally, I can see that as the size of the PSV increases, for balanced spring loaded valves, the bellow pressure limits tend to reduce as well, I am sure this is relevant to ASME B16.34 but what is the physical behavior behind having the bellow pressure limit decreasing as the PSV sizes increase for example for D throughout T.
Appreciate your views
regards,
