Double block and bleed valve for fluid mixt. prevention

摘要

The valve serves for two media supply to machines and installations without mixing together. Two feed valves are located in the coupled pipelines and a relief third valve is incorporated in the intermediate space, open with the two feed valve closed, and vice versa. The insertion of a double block and bleed (DBB) valve realises controlled discharge of leakages into atmos. The DBB valve has three valve seats on a disc piston, and only one drive is used for the valve positioning, as well as a simple monitor for the end position. Switching of three connecting unions serves for the valve operation.