Time for pressure to drop through Relief Valve
Time for pressure to drop through Relief Valve
(OP)
I appologize for the stupid question in advance but I am not very well versed in fluids. I have a system which actuates a relief valve when the air pressure falls to 60 psi. I am looking for the method of finding out how long it takes to exhaust that pressure to atmosphere. The pipe runs about 100 ft with various bends and valves. Is there an easy way to find the time for this? Thanks
Please let me know if any further information is needed.
Please let me know if any further information is needed.





RE: Time for pressure to drop through Relief Valve
Then just replicate that series of calculations across the row to new rows, The inut for row two pressure will come from row 1.
Then you can adjust the time increments and see if 1 minute changes are any less accurate than 1 sec time periods.
Its digital integration.
RE: Time for pressure to drop through Relief Valve
Earlier today I actually calculated the exit flow rate by use of Darcys Formula. Is this a valid method for this problem? I can't seem locate the API equation that you speak of.
So I now have the flow rate and initial volume and can get to that point of your given method. Then I get lost again. What do I use to find the new pressure based on the lower volume? Using boyles won't work as far as I can tell since if my volume lowers my pressure increases, which is opposite of what is happening here. Or am I just looking at it incorrectly?
Thank again
RE: Time for pressure to drop through Relief Valve
RE: Time for pressure to drop through Relief Valve
(DESIGN FLOW, MSCFD)= (AREA,SQ. IN.)/(((TEMP+460)*(SET PRESS*1.1+15)/(OPER PRESS*1.1+15)*(SP. GR.)*(Z))^0.5/((1.692)*(C1)*(K)*(P1)*(Kb)))
RE: Time for pressure to drop through Relief Valve
Relief may continue for as long as the event that causes the pressure to exceed MAWP (fire, open block valve etc).
Best regards Morten