Pressure drop to consider for Combination of Rupture disk and PSV
Pressure drop to consider for Combination of Rupture disk and PSV
(OP)
Hello...I was wondering what relief load (i.e. required or the capacity of the valve) to consider in calculating the inlet and outlet pressure drop for a PSV with a rupture disk upstream of this PSV. As per API, we consider the required relief load for stand-alone rupture disk. I am not sure if this is applicable for PSV with the rupture disk upstream. I have a case where considering the rated/capacity of the PSV would give a massive inlet pressure drop during fire. Also, in checking if the PSV is adequate, do we consider that it is stand alone PSV (except taking into account the flow resistance factor in the inlet hydraulic calculations)? This case seems weird. The rupture disk set pressure is set 50% of the set pressure of the PSV. Thanks for the thoughts...





RE: Pressure drop to consider for Combination of Rupture disk and PSV
Unless the PRV has a very small orifice (~F or smaller) you'll generally find that you can't satisfy the inlet loss requirement without a makeing the disk one size larger than the valve inlet.
RE: Pressure drop to consider for Combination of Rupture disk and PSV
RE: Pressure drop to consider for Combination of Rupture disk and PSV
RE: Pressure drop to consider for Combination of Rupture disk and PSV
RE: Pressure drop to consider for Combination of Rupture disk and PSV
Good luck,
Latexman
RE: Pressure drop to consider for Combination of Rupture disk and PSV
RE: Pressure drop to consider for Combination of Rupture disk and PSV
Be careful with using the 'default' value. I personnaly consider 3 by defualt for metallic disks, 1.5 for graphite ones, and 5.6 for composite ones.
RE: Pressure drop to consider for Combination of Rupture disk and PSV
RE: Pressure drop to consider for Combination of Rupture disk and PSV