etrobal
Mechanical
- May 27, 2008
- 39
gentlemen,
we designed the open discharge pipeline of our bellows type, pilot operated safety relief valves with a horizontal leg of 1600mm and a vertical leg of 1200mm. will this long discharge piping system have any impact on the valve's closing pressure? or re-set pressure?
the authorized psv technician would like to think that a back pressure will affect the re-set pressure of the valve. the tech is trying to re-calibrate the re-set pressure. the valves are 8-inch by 10-inch open discharge.
the set pressure is at 8.5 kscg with the closing pressure being the same. we also required in our technical data sheets that the discharge back pressure be at atmospheric.
is the re-set pressure the same as the closing pressure?
in the power piping code b311, appendix II, non-mandatory, the psv drawings shows an elbow immediately after the discharge flange. is it prudent to revise the installation to that shown in the appendix II? or can i justify our installation as being free from back pressures that might affect the re-set or closing pressure. the support systems were design to withstand the valves' over-pressure release.
have attached a picture for better feedback. appreciate any comments, positive or negative, as this would form part of my learning process. thank you.
we designed the open discharge pipeline of our bellows type, pilot operated safety relief valves with a horizontal leg of 1600mm and a vertical leg of 1200mm. will this long discharge piping system have any impact on the valve's closing pressure? or re-set pressure?
the authorized psv technician would like to think that a back pressure will affect the re-set pressure of the valve. the tech is trying to re-calibrate the re-set pressure. the valves are 8-inch by 10-inch open discharge.
the set pressure is at 8.5 kscg with the closing pressure being the same. we also required in our technical data sheets that the discharge back pressure be at atmospheric.
is the re-set pressure the same as the closing pressure?
in the power piping code b311, appendix II, non-mandatory, the psv drawings shows an elbow immediately after the discharge flange. is it prudent to revise the installation to that shown in the appendix II? or can i justify our installation as being free from back pressures that might affect the re-set or closing pressure. the support systems were design to withstand the valves' over-pressure release.
have attached a picture for better feedback. appreciate any comments, positive or negative, as this would form part of my learning process. thank you.