Double tube coupling and manufacturing method thereof

摘要

A coupling for a double tube is configured to connect with the double tube. The double tube includes an outer tube for a first fluid to flow therethrough. The double tube includes an inner tube provided inside of the outer tube and having an end protruding from the outer tube, the inner tube for a second fluid to flow therethrough. The coupling includes a branched portion brazed to an end of the outer tube and brazed to an end of the inner tube, with the end of the inner tube protruding outside through the branched portion. The branched portion is formed as a curved tube having a curved portion. The branched portion has an end joined to an end of the outer tube, with the curved portion having a through-hole for the inner tube to pass therethrough.