For the stop-check this is not correct. In many boiler installations a valve smaller than pipe size could and should be selected.

• 可是,用这种方法选择自动阻断止回角阀就可能产生错误。对于许多锅炉管道系统中,可能甚至应该选择公称通径小于管道直径的自动阻断止回角阀。