Pipe of composite construction for gas supply has inner gas tight pipe surrounded by layers of semipermeable material

摘要

The gas flows through the central space (4) of a circular-section pipe (2). The casing (3) of the pipe has a large number of small bores, which allow the escape of leakage gas from the pipe. A semipermeable sleeve (5) surrounds the porous casing and may have many small bores to allow the escape of any leakage gas. There is a space (7) between the sleeve and an outer protective casing (6).