Abstract: A heat exchanger and a heat exchanger core are disclosed. The heat exchanger core is formed from a strip of synthetic resin molded into multiple panels which are accordion folded to form the heat exchanger core. One embodiment is a counterflow core in which sides of each panel parallel to the longitudinal axis of the strip are divided to form a closed portion and an open portion. The opposite longitudinal sides are similarly formed but the portions are reversed. The sides of each panel perpendicular to the longitudinal axis of the strip are closed either by a hinge formed in the strip or by panel borders abutting each other. A second embodiment discloses a strip also formed into multiple panels and accordion folded. However, every second hinge has an opening so that when folded, a cross flow core is created. Both cores are mated with appropriately designed molded plastic housings to form effective but simple and economical heat exchangers.

Abstract: A process for economically forming and assembling heat exchangers is disclosed. The process begins with a roll of synthetic resin which is heated and then impressed with a series of alternating panels and hinges. The hinges are formed so as to provide for an accordion fold. The formed strip of material is then cooled, trimmed, measured and cut. Thereafter, the strip of material is folded in an accordion fashion. The folded core may be bonded or constrained so as to form two sets of fluid flow passages in an alternating manner. Depending upon the design of the panels formed in the strip of material, the cores will either be counterflow or cross flow. In addition, a housing is thermo formed and then assembled with the core to complete the heat exchanger.