| 摘要 |
PURPOSE:To lower the manufacturing cost of a water pipe unit, by fixing heat- collecting branch pipes to a water distributing main pipe and a water collecting main pipe by way of caulking. CONSTITUTION:An outer projection 2 is formed around the both end portions of a heat-collecting branch pipe 1, and through-holes 5 are formed in the side wall of a water distributing, main pipe 3 and a water collecting, main pipe 4. Both end portions of the branch pipe 1 are inserted into the through-holes 5 with a seal member 7 being interposed therebetween, and then inner projections 6 are formed by bending the inserted portions of the branch pipe 1 outwards by way of plastic deformation, whereby the branch pipe 1 can be coupled to the main pipes 3, 4 in the manner of holding te side wall of the main pipes 3, 4 between the outer and inner projections 2 and 6. |
