Issues with pressure vessel safety valves
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Can a short circuit be added at the location where the safety valve is connected to the top of the pressure vessel’s drum, with a shut-off valve installed afterward and then the safety valve? Is it required that a shut-off valve be installed first at the top before the safety valve?
A globe valve can be installed in front of the safety valve; it is placed there mainly to facilitate the calibration of the safety valve, or to close it in case of a malfunction or during calibration. Under normal circumstances, it should not be closed.
In principle, no additional valves are allowed to be installed on containers and safety valves. If it is necessary for the purpose of testing, a ball valve must be installed, as it is easy to use and can effectively prevent accidental misoperations; moreover, a marker indicating that the valve should remain open should be attached to it.
A gate valve should be installed, and it should be sealed with lead!
We have isolation valves in front of the safety valves at the top of the steam drum in our units. The design from 2002 was not approved, but it was still added later on; in 2012, the same installation and the same design institute also added it.
It should be possible; our company has this type of installation in use on site
A valve can be added, but it should be opened fully when in use and sealed with a lead seal
The specifications state that it is not advisable to install such valves, but in practice, they are usually added anyway!
What I saw was not only a stop valve added, but also a 30-centimeter short circuit installed between the flange on the wall and the stop valve. . . . .
For details, see Clause 8.3.5 of TSG R0004-2009.