Precautions for the use of plate heat exchangers
Plate type or corrugated type should be based on the actual needs of the heat exchange places.For large flow pressure drop allows small, should choose small resistance of the plate type, vice choose resistance of plate type.According to the fluid pressure and temperature, determine the removable type choice, or brazing type.Plate type is unfavorable choose veneer board piece area is too small, in order to avoid board piece of too many, small flow rate between plate, heat transfer coefficient is too low, for larger heat exchanger more attention should be paid to the problem.Process refers to a medium plate heat exchanger in a set of parallel flow, flow direction and flow within the dow plate heat exchanger, consisting of two adjacent plate medium flow channel.In general, several port connected in parallel or serial way, in order to form the different combination of cold and hot media channels.Process combination shall be computed according to the change of heat and fluid resistance, in satisfies the requirement of process conditions under the determined.Try to make the cold, hot water flow passage of convection heat transfer coefficient is equal or close to, to get the best heat transfer effect.Because the heat transfer surface on both sides of the convective heat transfer coefficient is equal or close to the heat transfer coefficient for larger values.Although velocity varies among different plate, plate heat exchanger in the change of heat and fluid resistance calculation, is still at an average velocity to calculate.Due to the "U" shape of the single process over all fixed on the pressure plate, tear open outfit is convenient.In design, selection of plate heat exchanger and generally have a request for the pressure drop, so deal with it to check.If check pressure drop exceeds allowed pressure drop, redesign to type selection calculation, until meet the technological requirements.
