1) Is the pilot valve of a POSV a conventional or balanced type ?
2) If conventional, does it have the same simmer and blowdown as a normal conventional PSV ?
3) Does this affect the characteristics of a POSV ? If not, why not ?
4) How is the pilot of the POSV sized ?
5) How is it ensured that the dome pressure reduces when the pilot PSV opens i.e. the dome does not get "re-filled" through the pick-up line ?
4) Dome area of the main POSV is more than its bottom area. Why and by how much ?
5) What is the simmer and blowdown characteristic of a balanced bellows PSV ?