Patent ID: 6923251

Claim:
A layered heat exchanger comprising: a multiplicity of generally rectangular intermediate metal plates each having at least one channel recess formed on one side thereof and at least one pair of upper and lower header recesses communicating with respective upper and lower ends of the channel recess and having a greater depth than the channel recess, each of the upper and lower header recesses having a fluid hole formed in a bottom wall thereof, each of the intermediate plates being fitted to the intermediate plate immediately adjacent thereto in juxtaposed layers with the recessed sides thereof opposed to each other, the pair of adjacent intermediate layers being joined to each other at peripheral edges thereof to thereby form at least one flat tube portion and at least one pair of upper and lower header portions communicating with the flat tube portion so that the heat exchanger has a multiplicity of flat tube portions and many upper and lower header portions arranged in parallel, a flat metal plate being interposed between one pair of intermediate metal plates providing the flat tube portion at a specified intermediate portion of the heat exchanger with respect to the direction of juxtaposition of the intermediate plates, the flat metal plate having a partition portion for blocking the passage of a fluid through the specified one of the upper and lower header portions communicating with the flat tube portion provided by said one pair of intermediate plates and a fluid passing hole for permitting passage of the fluid through the other header portion, a fluid channel being formed in the flat tube portion and the upper and lower header portions, wherein an edge portion around the fluid passing hole formed in the flat metal plate is provided with a guide protuberance for diffusing the fluid flowing through the fluid passing hole into the header, wherein the guide protuberance guides the fluid flowing through the fluid passing hole to the flat tube portion in the vicinity of the fluid passing hole, and wherein the guide protuberance is provided at an edge around the fluid passing hole of the flat plate and is shaped as to resemble a portion of a spherical surface.