Which of the following statements concerning butterfly valves is correct?()

A . Special tools are required for lapping or grinding B . It is impossible to throttle flow with a butterfly valve C . To close the valve, it is only necessary to turn the handle a quarter of a turn D . The butterfly valve should never be used in a freshwater system

时间:2022-09-16 23:32:38 所属题库:船舶辅助机械题库

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