Gas non-return valves (check valves) protect systems, outlet points and pipelines against unwanted and potentially hazardous gas mixtures. For applications in the high-pressure range, German manufacturer WITT provides two models – one with a maximum operating overpressure of 300 bar – in its current 600H and 800-ES series.
The 600H model with brass housing can be used for combustible gases, oxygen and non-flammable gases. It has a particularly sensitive mechanism and reacts from about 250mbar opening pressure. Its maximum operating overpressure is 40 bar. With compact dimensions and position-independent installation, a broad spectrum of applications is possible. The ambient temperature may be 70°C. Several connection sizes with G threads are available, as well as a stainless steel version (600H-ES).
The 800-ES model can withstand pressures as high as 300 bar when used with combustible gases and 240 bar when used with oxygen. This stainless steel model is suitable for a large number of technical and corrosive gases. It can be installed independently of environmental constraints, which means the ambient temperature at the installation site can be up to 150°C with fuel gases and 60°C with oxygen. According to WITT, the spring-loaded valve system with elastomer seal ensures maximum leak-tightness. It opens at 2 bar (29 psi) and above.