Help needed regarding valve selection issues
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Why are threaded connections used for the valves on heating radiators at home, while flanged connections are more commonly used in chemical plants? Generally speaking, under what circumstances are threaded connections used in factories?
Pressure, flow rate, temperature, and medium are the basic parameters for selecting valves
If the financial conditions permit, then flanges are of course the better choice, as they make maintenance easier
Threads are so cheap. . Flanges are much more expensive. . The flange is easy to replace.
A household thread will do; the pressure isn’t very high. Flange connections are used in high-pressure applications with large diameters. As for the convenience of maintenance mentioned above, I don’t think it exists; the threads can be removed directly, and blind flanges can be used on the flanges to prevent water leakage.
The diameter of radiators is quite small; threaded valves are generally used for them. For large-diameter pipes carrying heat or gas in urban areas, flanges are required, and in factories as well, the choice of valve depends on the pipe diameter
Generally, threaded connections are used for those with a diameter of DN40 or less, while flanges are used for those with a diameter of DN50 and above. Screws are cheap, small, and take up little space.
For galvanized pipes, threads are used for DN40 and below, while flanges are used for those above. For safety reasons, factories use flanges, but for pipelines carrying hazardous chemicals, it is stipulated that flanges should be used as little as possible in pipe connections, with direct welding being preferred.