US Patent 7331615 Pipe union with extension

A pipe union with extension for interconnecting a first length and a second length of coaxial pipe may include a first annular pipe member attachable to the first length of pipe. The first annular pipe member may incorporate a circumferential flange having a shoulder. The first annular pipe member may comprise a front face which faces the first length of pipe, and a rear face which faces in a direction of the second length of pipe. The pipe union may also comprise a fastening member incorporating an inwardly extending flange with a central passageway adapted to fit around the first annular pipe member. The inwardly extending flange may be adapted to abut the shoulder as the fastening member is fitted over the first annular pipe member. The fastening member may comprise thread means formed on an inner surface of the fastening member.