Dual gas source changeover valve and control cabinet and gas supply system

摘要

A dual gas source changeover valve comprises a valve body having a first inlet port, a second inlet port and an outlet port which are all in fluid communication with each other, a spool having a structure relative to an axial passage of the cavity of the valve body and which is slidably disposed therein, a first transition cavity formed by the cavity of the valve body and the spool between the first inlet port and the outlet port, a second transition cavity disposed opposite to the first transition cavity and formed between the second inlet port and the outlet port. By introducing delivered gas to the first transition cavity or the second transition cavity through connection channels, the present invention selectively connects or disconnects the first inlet port, the first transition cavity and the outlet port or the second inlet port, the second transition cavity and the outlet port.