The check valve is a shut off device, developed for feed-water piping in high-pressure boilers and pumps. The check valve opens, automatically caused by the flow of the medium and shuts due to the gravity effect of the swing plate causing counter-pressure in case of flow interruption. Thanks to the glandless fitting of the valve shaft, a trouble-free and simple operation is guaranteed. Furthermore, needing no gland, leakage is quite impossible. The check valve is basically equipped with a self-sealing cover-plate. lt is also employed as a safety device to check reverse-flow in pipelines carrying superheated steam and in long distance pipes systems with highest pressure ranges.