2 replies to this topic

[cmp74]

Hello,

We are installing a 10" PORV where we have to option.

1) build a new 10" nozzle on tank .

2) Tank has a 24" bling on the roof (10" height).Install this PORV on this 24" flange ,with a short 10" nozzle(10" height) on this flange .

The Set pressure for the PORV is 1.5 KPag (0.21 psig).

My question is , if i use option 2), how do i calculate inlet pressure drop using "K" value.I calculated "K" value using equation given on crane paper,page A-26(SI)?I ran a SINET simulation and it gives pressure drop of about 28% of set pressure(largely because 28" to 10" sudden contraction).

thanks all.

[djack77494]

I would ignore the presence of the 24" or 28" short segment. It has six times the cross-sectional area or roughly 1/36 * the kinetic energy compared to the 10" segment. Essentially all your dP can be considered the tank to 10" segment entrance loss.

[JoeWong]

No surprise with low set pressure of 1.5 kPag. Connect the pilot to the 28" flange. Ensure the PORV is size for CORRECT differential pressure to avoid undersized PORV.