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Plate Heat Exchanger

Heat Exchanger

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Plate Heat Exchanger
Plate Heat Exchangers consist of a number of very thin corrugated stainless steel heat transfer plates clamped together in a frame. Every second channel is open to the same fluid. Between each pair of plates there is a rubber gasket, which prevents the fluids from mixing and from leaking to the surroundings. Heat is thus transferred from the warm fluid to the colder fluid via the thin stainless steel plate. The corrugations support the plates against differential pressure and create a turbulent flow in the channels. In turn, the turbulent flow provides high heat transfer efficiency, making the plate heat exchanger very compact compared with the traditional shell-and-tube heat exchanger. In most cases the plate type heat exchanger is the most efficient heat exchanger. Generally it offers the best solution to heating and cooling applications since it can better handle the widest pressure and temperature limits.

Advantages of a plate heat exchanger are that they utilize the thinnest material for the heat transfer surface that in turn gives optimum heat transfer, since the heat only has to penetrate thin material. Also, there is a high turbulence in the medium that in turn gives a higher convection, which results in efficient heat transfer between the media. The consequence of this higher heat transfer coefficient per unit area is not only a smaller surface area requirement but also a more efficient process. The high turbulence also gives a self-cleaning effect. Therefore, when compared to the traditional shell and tube heat exchanger, the fouling of the heat transfer surfaces is considerably reduced. This means that the plate heat exchanger can remain in service far longer between cleaning intervals. Since the plate heat exchanger consists of a framework of plates, more plates can easily be added to increase capacity, and the plates can easily be spread apart for cleaning.

Disadvantages of plate heat exchangers are their initial expense, they don't work well under high pressure rates and they are not well suited for processing pulpy products or product with particulates. The corrugated plate causes contact points that are required for rigidity, and "pinch" points are created which allow for retention of the pulp and particulates. This effectively creates an undesirable filter. This limits your ability to process more than one type of product on a single system, such as orange juice with pulp and a clear fruit drink that must contain no pulp. Trying to keep the plate heat exchanger clean before running a new product can prove very difficult, if not impossible.



© Genemco, Inc. 2006