Spiral tube double walled heat exchanger - has fixed or loose joint between walls over entire length

摘要

The heat-exchanger incorporates a double-walled spiral tube, and has one or more loose or fixed joints, in spot or line form, running for the entire tube length, between the inner (2) and the outer (1) wall. The joint can typically be a lengthwise rib (3) in one of the walls, by which it is welded to the other, or merely pressed against it, or the outer wall can be of oval section so as to bear against the inner one. The inner wall can run in a spiral inside the outer one, and a force can be applied to it in the lengthwise direction during the bending operation, so as to press it against the outer one.