... automatically. When the medium is back-going, valve disc will automatically closed to avoid accidents.2.Working Temp: 0 ... . When the medium is back-going, valve disc will automatically closed to avoid accidents.2.Working Temp: 0 ... Valve,Spring Swing Check Valve,Brass Check Valve.CheckBrass Compression Type Swing Check Valve,15mm,22mm wall mounted ,Check Valve,Spring Swing Check Valve,Brass Check Valve ...