[Q&A Question 170] 2016.10.07
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【Q&A Question 170】October 07, 2016: When the safety valves of a tower tank are operated in one active and one standby mode, what is the status of the manual valves before and after the valves? Why? The answer key will be available after responding; scoring is based on answering the key points. Answer: For normal operation, the manual valves before and after the safety valve should be fully open, while the bypass valve should be closed ； The valve upstream of the backup safety valve is closed, the valve downstream is open, and the bypass valve is closed. Since the front valve is under high pressure, its pressure rating is generally higher than that of the rear valve; this prevents the rear valve from being damaged in the event of a leak in the front valve.
It should be fully open; otherwise, the safety valve will not function.
The inlet and outlet valves must be fully open to allow pressure to be released in case of overpressure, thereby protecting the equipment.
The manual valves before and after the opened valve remain in the open position, while the manual valves before and after the backup safety valve are closed