Brazed plate heat exchanger

Abstract

A brazed plate heat exchanger comprises alternating first and second heat exchanger plates each having two long side edges, two short side edges and a longitudinal axis parallel to the long side edges. Each first and second plate has a corrugation pattern forming a heat transfer area comprising mutually parallel ridges and grooves in which the ridges of one first plate abut the grooves of an adjoining second plate. Each ridge and groove of at least one first heat transfer area of each first late is inclined between 0° and 30° relative to the longitudinal axis. Each ridge and groove of at least one heat transfer area of each second plate is inclined between 90° and 45° relative to the longitudinal axis. Part of the ridges and grooves of each first plate extend without discontinuities between opposite edges of the heat transfer area parallel to the short side edges

1 . A brazed plate heat exchanger comprising a plurality of heat exchanger plates which are stacked onto one another, wherein said heat exchanger plates are obtained by forming from respective metal sheets, wherein said heat exchanger plates are permanently joined to each other through brazing by means of a braze material, so as to form a plate package provided with first plate interspaces for a first fluid and second plate interspaces for a second fluid, wherein said plate package comprises an alternation between a first heat exchanger plate and a second heat exchanger plate, wherein each between said first heat exchanger plate and said second heat exchanger plate is provided with a plurality of portholes and has a substantially rectangular shape, with two long side edges, two short side edges and a longitudinal axis extending parallel to said two long side edges and transversely to said two short side edges, wherein each between said first heat exchanger plate and said second heat exchanger plate has a corrugation pattern which forms at least one heat transfer area that extends along said longitudinal axis, and wherein each heat transfer area comprises mutually parallel ridges and grooves arranged in such a manner that the ridges of one of the first heat exchanger plates but the grooves of an adjoining one of the second heat exchanger plates, so as to form a plurality of joining areas,
 each ridge and each groove of at least one first heat transfer area of said first heat exchanger plate are inclined with respect of said longitudinal axis by a first angle between 0° and 30°;   each ridge and each groove of at least one heat transfer area of said second heat exchanger plate are inclined with respect of said longitudinal axis by a second angle between 90° and 45°;   at least part of the ridges and at least part of the grooves of at least a first heat transfer area of said first heat exchanger plate extend without discontinuities between the opposite edges of the respective heat transfer area, wherein said opposite edges are parallel to said short side edges.   
     
     
         2 . The brazed plate heat exchanger according to  claim 1 , wherein said first angle is 20°. 
     
     
         3 . The brazed plate heat exchanger according to  claim 1 , wherein said second angle is 70°. 
     
     
         4 . The brazed plate heat exchanger according to  claim 1 , wherein an amount of the ridges, and thus of the grooves, of the first heat transfer area of each first heat exchanger plate that extend without discontinuities between the opposite edges of the respective heat transfer area is equal to at least 30% of a total amount of the ridges, and thus of the grooves, of the first heat transfer area of said first heat exchanger plate. 
     
     
         5 . The brazed plate heat exchanger according to  claim 1 , wherein each of said first heat exchanger plates is provided with at least one second heat transfer area which is adjacent to said first heat transfer area. 
     
     
         6 . The brazed plate heat exchanger according to  claim 5 , wherein each ridge and each groove of said second heat transfer area are inclined with respect of said longitudinal axis by a third angle between 45° and 90°. 
     
     
         7 . The brazed plate heat exchanger according to  claim 6 , said third angle is 65°. 
     
     
         8 . The brazed plate heat exchanger according to  claim 5 , wherein at least part of the ridges and at least part of the grooves of said second heat transfer area extend without discontinuities between the opposite edges of the respective second heat transfer area ( 38 ), wherein said opposite edges are parallel to said short side edges. 
     
     
         9 . The brazed plate heat exchanger according to  claim 5 , wherein said second heat transfer area has a longitudinal extension, measured along said longitudinal axis, that is equal to about ⅓ of the longitudinal extension of said first heat transfer area. 
     
     
         10 . The brazed plate heat exchanger according to  claim 1 , wherein each ridge and each groove of each heat transfer area of both said first heat exchanger plate and said second heat exchanger plate are straight and continuous along the respective heat transfer area. 
     
     
         11 . The brazed plate heat exchanger according to  claim 1 , wherein said longitudinal axis is a vertical axis. 
     
     
         12 . The brazed plate heat exchanger according to  claim 1 , wherein each between said first heat exchanger plate and said second heat exchanger plate is provided with four portholes, wherein each porthole is placed at a respective corner of the respective heat exchanger plate, that is, at the contact point between a long side edge and a short side edge of the respective heat exchanger plate. 
     
     
         13 . The brazed plate heat exchanger according to  claim 1 , wherein at least one of said portholes is placed at a distance from its closest long side edge which is different from the distances from the respective closest long side edge of remaining portholes. 
     
     
         14 . The brazed plate heat exchanger according to  claim 13 , wherein said distance of said at least one porthole is greater than said distances of the remaining portholes. 
     
     
         15 . The brazed plate heat exchanger according to  claim 12 , wherein each corner of each heat exchanger plate is a rounded corner.