Abstract: Heat exchanger core comprising flat plate fluid U flows tubes stacked on one another and operatively connected to one another by discrete fluid supply and suction lines. These lines extending through side-by-side tank portions of the tubes to improve structural integrity of the core and respectively have fluid feed and exhaust openings communicating with the tanks and sized to provide even distribution of the heat exchanger fluid to the tubes. With the supply and suction lines, evenly distributing the heat exchanger fluid, tank size and capacity is optimized and the requirement for large capacity deep draw tanks of prior constructions is eliminated.

Abstract: A multi-pass U-flow type evaporator for an air conditioning system provided with a flow control insert which allows the inlet port and the outlet port to be located on the same face of the evaporator core and in close proximity to each other.

Abstract: A chromate/silicate surface treatment for providing an aluminum heat exchanger with a corrosive-resistent hydrophilic coating. The subject process includes sequentially immersing an aluminum heat exchanger in a series of chemical solutions. The chemical solutions include a cleaning solution, followed by a rinse solution, chromate solution, additional rinse solution, and a silicate solution. The chemical concentrations of the cleaning solution, chromate solution and silicate solution are precisely controlled in order to avoid producing a coating which emits a musty odor.