Questions about the bottom valve
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It seems that bottom valves are generally used in water supply and drainage systems, so I don’t know much about them; I only know that they are a type of lift-type check valve. There is a project that requires a bottom valve, which will be placed in the coke cutting water lift tank. I’ve seen many samples where the valve body is made of cast iron, the sealing ring is made of rubber, and the gasket is made of asbestos board. . But I remember that asbestos is no longer allowed to be used. . . Please explain. Also, since it’s constantly in water, is there any treatment that needs to be done? . .
It’s okay if the bottom valve leaks a little. Use an oil-resistant rubber gasket.
You can use oil-resistant rubber gaskets, or even PTFE ones; you can handle it by yourself.
A foot valve is generally installed when the pump’s suction inlet is below the pump’s installation baseline, to prevent liquid in the inlet pipeline from leaking when the pump is not in use, thereby ensuring smooth operation when the pump is started again. However, in reality, none of the bottom valves can fully meet the aforementioned requirements; leakage generally occurs due to particles present in the medium. Therefore, a vacuum pumping device or a water supply line is installed at the pump inlet to ensure that the pipeline at the pump inlet is filled with liquid when starting the pump. In our facility, the bottom valve is installed at the inlet of the sludge pump in the sludge tank, submerged within it; the gaskets we use are oil-resistant rubber gaskets. It is recommended that the original poster replace the asbestos gaskets with oil-resistant rubber gaskets, as asbestos gaskets cannot withstand prolonged exposure to oil.