Heat exchange plate

A heat exchange plate, which is formed of a metallic plate and has a predetermined pattern of irregularity, the heat exchange plate being placed on another heat exchange plate having a same structure so as to come into contact with each other on a same side of the heat exchange plate to provide a pair of heat exchange plates, the pair of heat exchange plates being combined to one or more other pair of heat exchange plates integrally with each other to form a heat exchanger in which heat exchange is to be made between first and second heat exchange fluids that come into contact with opposite surfaces of the heat exchange plate, respectively, the heat exchange plate comprising:

• a plurality of protrusions that are placed in a predetermined arrangement on a surface of the metallic plate;
• and
• a plurality of recesses each of which is placed between two or more protrusions of said plurality of protrusions on said surface of the metallic plate so as to dent in an opposite direction to a protruding direction of said protrusions, said plurality of protrusions and said plurality of recesses providing said predetermined pattern of irregularity;
• wherein:
• each of said protrusions has a curved outer peripheral surface, one protrusion of said plurality of protrusions is surrounded by adjacent protrusions of other protrusions, said adjacent protrusions being placed at regular intervals on a circle around said one protrusion and with a same central angle relative to a center of said one protrusion;
• each of said recesses has a curved inner peripheral surface that partially extends to the curved outer peripheral surface of said protrusions, said recesses being placed in a predetermined arrangement that is deviated by a same pitch from the predetermined arrangement of said protrusions;
• and
• said recesses provide on another surface of said metallic plate with a same configuration as said plurality of protrusions and said protrusions provide on said surface of said metallic plate with a same configuration as said recesses, so as to provide on the opposite surfaces of the metallic plate with a same pattern of irregularity.