Improvements in Ventilating Pipes for Colliery and other purposes.

摘要

115,555. Wrightson, W. P. Aug. 14, 1917. Metal pipes.-A line of piping for collieries &c. is formed of connected sections. Each section is formed of three bent sheets X, Y, Z riveted or brazed together to form a length of piping, and corrugated near the joints to give strength. The sections are joined together by inserting the tapered end A of one section into the mouth B of the next, corrugations C being provided to limit the length inserted.