A pipe connecting structure including a male flange block combined with a first pipe and a female flange block combined with a second pipe, which is fastened to the male flange block by a fastener, where a protrusion having a hole that communicates with the first pipe is formed through the male flange...http://www.google.fr/patents/US7766391?utm_source=gb-gplus-shareBrevet US7766391 - Pipe connecting structure
