Patent ID: 7168483

Claim:
A heat transfer plate for a plate heat exchanger, comprising an inlet portion, an outlet portion and a heat transfer portion which is located between the inlet portion and the outlet portion and which presents a number of ridges and troughs pressed into the plate and extending between a geometric top plane and a geometric bottom plane of the plate, said planes being essentially parallel to a geometric central plane of the plate, wherein the heat transfer portion has a plurality of juxtaposed rows of said ridges and troughs, said rows extending along a main flow direction which extends between the inlet portion and the outlet portion, the rows of ridges and troughs are separated from each other in a transverse direction, which is essentially perpendicular to the main flow direction and extends along the central plane of the plate, by essentially plane channel portions of the heat transfer portion, which extend essentially parallel to the central plane of the plate, each row has alternating elongated ridges and elongated troughs which extend along said main flow direction, the transition between each ridge and an adjacent trough in the same row is formed by a continuous, essentially straight transition portion of the plate, which is inclined relative to said central plane of the plate and of which a first part forms an end wall of said ridge and a second part forms an end wall of the adjacent trough, and each channel portion is stepwise divided into a number of essentially plane step portions which are arranged one after the other in the main flow direction and displaced in relation to each other along a normal to the central plane of the plate.