Flat-tubed heat exchanger

Abstract

A heat exchanger with an improved flat-tubed design is disclosed. The heat exchanger includes plural tubes of relatively flat cross-section in parallel array. Each tube is comprised of relatively flat first and second plates in facing contact. The first plate of each tube has a plurality of first grooves extending at a first oblique angle with respect to a major axis of the corresponding tube. The second plate of each tube has a plurality of second grooves extending at a second oblique angle with respect to the major axis of the corresponding tube, such that the first and second grooves define a cross-hatched pattern of channels to accommodate flow of heat transfer fluid through the corresponding tube. The first grooves are defined by corresponding first ridges on a first major surface of the first plate and the second grooves are defined by corresponding second ridges on a second major surface of the second plate. The first and second major surfaces are in facing relationship and each of the first ridges is in contact with at least one of the second ridges. The first grooves are located above the second grooves. When the heat transfer fluid consists of fluid in both liquid and vapor states, the heavier liquid will tend to flow through the second grooves while the lighter vapor will tend to flow through the first grooves. Because the first grooves extend in a different direction from the second grooves, separation between the liquid and vapor within the tubes is enhanced.