valve interlocking system HSV - safeguarding of pressure safety valves

Compliance with sequences

Wherever piping is used for production processes, pressure safety valves (PSV) can befound. To prevent over pressurisation within the system during maintenance work, it must be ensured that a minimum number of PSV lines is always opened. The use of our valve interlocking systems HSV® ensures that a predefined, safe sequence of opening and closing of the corresponding valves is maintained. In the below example of a chemical production site both PSV lines are open during normal operation. The operator must close a line before maintenance work can be carried out. Our valve interlocking systems HSV® guarantee that the operator can only close one of the two lines at any time.

This realisation of the safety requirement is illustrated in our key logic diagram. With the start key A, which is safely stored in the control room, the authorised operator can decide which of the two lines should be closed. This key is designed in such a way that it can unlock both inlet valves of the two PSV lines. As the key is trapped after closing the selected valve, it ensures that the second line cannot be closed if the first line has already been closed. Only after the line to be services has been fully re-opened, key A is released and can be used to close the other line.