diaphragm control valve bellows seal bonnet-two way size: 1/2", 3/4", 1", 11/4", 11/2", 2", 21/2", 3", 4" diaphragm control valve bellows ... seal bonnet-two waysize: 1/2", 3/4", 1", 11/4", 11/2 ... :TC control valves are generally used eigher to mix flowing medium or to divert one medium into two outlet flows and are ...