The new NV range of gas non-return valves from Witt Gas Techniques, the Warrington-based gas safety, control, mixing and analysis equipment supplier, are safety devices designed to stop the return flow of gases in gas supply pipelines used in shipyards, gas production plants, treatment works and gas distribution systems. There are 6 models in the range comprising NV100, NV200, NV300, NV400, NV800 and NV2000 with flow ranges up to 26,800m3/hour. All are designed to be installed in any orientation, as the spring loaded valve is not affected by gravity (except NV2000) with opening pressures as low as 4mbar even when mounted in the vertical plane. They can be used in pipelines supplying butane, hydrogen, methane, natural gas, LPG, propane, compressed air and non-flammable gases to prevent flammable mixtures being formed. The NV100 has a maximum working pressure of 25bar, whilst the NV200, NV300 and NV400 have a maximum working pressure of 16bar.
