The invention is an improved line blind valve which provides absolute positive flow shut-off in piping systems. It uses fluid pressure to separate the seal surfaces while ensuring the end connections do not move relative to each other. Once separated, the blind can be moved easily into either the closed blind position or the open full flow position. The assembly consists of an outer housing, two end pipes and a sliding carrier that allows a blind to be either inserted into the flow or removed by pivoting the blind about a pin.