The working principle of plate heat exchangers is based on inter-wall heat transfer, and heat is exchanged through metal plates. The plate heat exchanger is made up of a series of metal sheets with a certain corrugated shape stacked together. Thin rectangular channels are formed between these plates. Cold and hot media flow in the respective channels respectively and exchange heat through the plates.
The construction of the plate heat exchanger includes gaskets, pressing plates (movable end plates, fixed end plates) and frames (upper and lower guide rods, front pillars). The plates are sealed and guided by sealing gaskets to separate two cold/hot fluid channels. The cold/hot heat exchange medium flows through the respective channels respectively to exchange heat with the separated plates. Each plate has holes at the four corners. After assembling into a plate bundle, a distribution pipe and a collecting pipe for the fluid are formed. After heat exchange of the cold/hot medium, it flows back from the respective collecting pipes and is recycled.
Plate heat exchangers have the characteristics of efficient heat transfer, compact structure, small footprint, and wide application. Its heat transfer coefficient is 3-5 times higher than that of a tubular heat exchanger, and its area is one-third of that of a tubular heat exchanger, and its heat recovery rate can be as high as more than 90%. In addition, plate heat exchangers are not easy to scale, and the interior is fully turbulent, and the scale coefficient is only 1/3-1/10 of that of shell and tube heat exchangers. However, since it is sealed with a gasket, the working pressure should generally not exceed 2.5MPa, and the medium temperature should be below 250 ° C, otherwise it may leak.
