PLATE TYPE HEAT EXCHANGER

PURPOSE:To intend to improve performance of exchanging heat, by providing a heat transmitting promotor to the part of a flow path of a heat exchanger other than a cross flow part, in a heat exchanger having a cross flow part so as to be designed to flow fluids having different temperatures, directly crossed to each other, at the outlet of the fluid. CONSTITUTION:Turbulent flow promotors in order to disturb the flow of fluid, twisted strips 3, for example, are inserted into the flow path of the fluid only on the high temperature side and the low temperature side of the counter-flow path 2, along the longitudinal direction of the flow paths. The said twisted strips 3 are fixed to plates or partition walls of a heat exchanger. When the fluids on the high temperature side and the low temperature side flow into the counter-flow part respectively, the flow of these fluids are disturbed because of the existence of the twisted strips 3. By these turbulences, the temperature boundary layer which is the resistance to transfer heat is decreased, and the heat transfer rate between the fluid and the solid surface inside of the flow path can be increased, accordingly, the heat transfer rate of a heat exchanger can be increased. By promoting heat transfer in such a manner, 1/50-1/20 out of total heat exchanged calorific value is absorbed into the cross flow part 1 in the above- mentioned form of a heat exchanger and under the temperature condition, so that the difference in temperature at the outlet of fluid can be suppressed down to the range at 5-15 deg.C.