What is the difference between flange and valve?

　　Valve is the same thing as faucet, or faucet is one of the valves. If you can turn it on, water or air will flow out; if you can turn it off, water will not flow.

　　The tap in the house is screwed on the pipe with thread, but some pipes used in the factory, water or gas inside, have a high pressure, and ASME 304 stainless steel plate flange is strong enough to be connected with thread, so they are directly welded or connected with other methods. Flange is one of the connection methods.