The blind flange is so named due to the lack of a bore: it is a solid flange. It is used to close off the ends of piping systems and pressure vessel openings. As such it can be used in an existing operation flow, or for future expansion requirements.
A blind flange is a solid disk used to block off a pipeline or to create a stop. Similar to a regular flange, a blind flange has mounting holes around the perimeter and the gasket sealing rings are machined into the mating surface. The difference is that a blind flange has no opening for fluids to pass through. Instead, it is placed in between two open flanges, which stops the flow through a pipe. Many times this type of blockade is used when adding another line onto an existing pipeline or when a new valve is being added.
Blind flanges are commonly used in petrochemical, pipe engineering, public services and water works.
A blind flange is useful for making repairs to a pipeline further up the line. In fact, during construction of a pipeline, a blind flange may be built into the final length of pipe. This allows for expansion or continuation of the pipeline simply by adding onto the final flange.