The RITAG Type ZRD dual plate check valve is the most universal check valve among the nonreturn valves. It is available in a broad spectrum of nominal diameters and nominal pressures. Thanks to the dual-plates, which create the optimum dynamic flow behaviour, this valve design has proven to be an outstanding solution for most process requirements in plants and pipe systems. The dual plate check valve is perfectly suited for use with vapours, gases and liquids.The well thought through design requires no drilling in the housing (retainer-less design) and therefore has no housing seal other than the flange seal. Thus, testing for volatile emissions (fugitive emissions) is not required.