HEAT EXCHANGER WITH FLOW OBSTRUCTIONS TO REDUCE FLUID DEAD ZONES

A heat exchanger comprises: (a) at least one plate pair comprising a first plate and a second plate and having a first end and a second end; (b) a fluid flow passage for flow of a first fluid defined between the first plate and the second plate of each of said plate pairs; (c) an inlet opening and an outlet opening provided in each of said plate pairs, wherein the fluid flow passage extends between the inlet opening and the outlet opening, and wherein the inlet opening and the outlet opening in each said plate pair are proximate to the first end; (d) an elongate flow barrier separating the fluid flow passage of each said plate pair into an inlet portion in which the inlet is located, and an outlet portion in which the outlet is located, wherein the flow barrier extends from the first end to a terminal end proximate to the second end of the plate pair, and wherein the flow barrier includes a gap through which fluid flow communication is provided between the inlet portion and the outlet portion of the fluid flow passage; and (e) a flow obstruction located in the gap of each said plate pair, the flow obstruction having a pair of opposed ends, a first side and an opposed second side, wherein the first and second sides are arcuate, with the first side facing the terminal end of the flow barrier and spaced therefrom; wherein the flow obstruction is substantially crescent-shaped and the first and second sides of the flow obstruction intersect at the opposed ends thereof; wherein the first and second sides of the flow obstruction each describe a portion of a smoothly rounded shape, wherein the portion of the smoothly rounded shape described by the second side is larger than the portion of the rounded shape described by the first side, such that a middle portion of the flow obstruction is wider than the opposed ends.