the present invention relates to a laminated heat exchanger having a laminated construction consisting of a plurality of perforated heat transfer plates and spacers arranged alternatingly , the spacers defining a plurality of fluid passages between respective adjacent heat transfer plates , so that heat is exchanged between different fluids flowing in different fluid passages through the heat transfer across the heat transfer plates . more specifically , the invention is concerned with a heat exchanger of the type described above , wherein a plurality of separate scroll passages are formed by the spacer , so that local concentration of each fluid in its passage is avoided to remarkably improve the heat transfer efficiency .