EPC School: TWO SOV SCHEME

TWO SOV SCHEME

TWO SOV SCHEMATIC (See Scheme Below)

Two sov’s are used in order to have redundant air supply arrangement to valve. Now consider following cases:

Both SOV A & B are Energized: in this case air supply is through SOV A, since SOV B exhaust is blocked because vent port of SOV A is closed.
SOV A Failed and SOV B Energized: Since SOV A is failed so vent/exhaust port of SOV A is now open, hence exhaust of SOV B will go via vent port of SOV A to SOV exhaust port.
SOV A Energized and SOV B Failed: Now SOV B vent port/exhaust port is open and SOV A is in line, but at the time of SOV A deenergizing vent of SOV A will pass via exhaust port of SOV B to vent port of SOV A. Hence depresurizing the system.

# posted by Rahulkap @ 5:34 AM

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