The two valves are connected directly by flanges; what is the purpose of having two valves in this setup?
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The two valves are connected directly by flanges; what is the purpose of having two valves in this setup?
It provides isolation during maintenance, and the use of dual valves offers additional protection; however, if a valve leaks, the probability of failure increases.
It is rare to see two valves connected directly; usually, there are short pipes and vents in between. But it’s definitely true that it has the function of a double valve. The dual valve can serve two purposes: one is to ensure no internal leakage when both valves are closed simultaneously ； The second one is a cut-off valve, while the other functions as an operating valve or a control valve.
The requirement for dual valves is based on safety considerations, to prevent loss of control in the event that one valve fails.
One is normally open; the other is damaged for easier maintenance. It’s best to add a short circuit and a drain in between to check for internal leaks
The two valves are directly flanged together； It’s rare these days ； The main issue is that it’s difficult to determine whether there is an internal leak when no short tube or vent is used in between ；