Heat exchanger plate and heat exchanger

A heat exchanger for heat exchange between a first medium and a second medium, comprising a main inlet for the first medium;

• a main outlet for the first medium;
• and
• a plurality of heat exchanging plates comprising at least one plate of a first type and at least one plate of a second type, each of said plurality of heat exchanging plates being associated with a respective main plane of extension and a respective height direction perpendicular to said main plane, said plurality of heat exchanging plates being fastened together in a stack on top of each other with their respective main planes parallelly arranged, said stack comprising said plates of the first type and said plates of the second type arranged alternatingly,
• each of said plates of said first and second types comprising
• a respective first heat transfer surface on a respective first side, arranged to be in contact with the first medium flowing along said first side;
• a respective second heat transfer surface on a respective second side, arranged to be in contact with the second medium flowing along said second side;
• a respective plurality of indentations, formed by the material of the plate bulging out locally in the said plate height direction, of which a plurality are bridge-shaped indentations comprising two respective through-holes through the plate material, as well as a respective bridge part forming a passage between the said through-holes, and wherein the passage has a general direction being substantially parallel to a general flow direction of the second medium past the bridge-shaped indentation;
• and
• a respective ridge-shaped indentation, arranged to form, together with a corresponding ridge-shaped indentation of an adjacent plate, at least one closed flow channel for the first medium from a first medium plate inlet to a first medium plate outlet,
• wherein each plate of the first type is fastened together with an adjacent plate of the second type by abuttal of a non-indented part of the first plate first heat transfer surface to a corresponding non-indented part of the second plate first heat transfer surface, wherein for at least a plurality of the said bridge-shaped indentations, the shape of the respective bridge part, in a cross-section taken perpendicularly to both the main plane and to the said general direction of the passage between said through holes, comprises a local minimum, so that the height of the bridge part, in said cross-section, first increases, then decreases to the said local minimum, and then again increases.