The plate heat exchanger is mainly composed of two parts(frame and plate). Plates made of various materials are pressed into corrugations of various shapes by various types of abrasive tools, and angular holes are formed in the four corners of the sheet for the flow path of the medium. The periphery of the plate and the corner hole are sealed with a rubber gasket. The frame is composed of a fixed pressing plate, a movable pressing plate, upper and lower guide bars, clamping bolts. The plate heat exchanger is formed by superimposing the plates in the middle of the fixed pressing plate and the movable pressing plate, and then clamping them with clamping bolts. In the design and selection of the plate heat exchanger, there is a certain requirement for the pressure drop, so it should be checked. If the check pressure drop exceeds the allowable pressure drop, the design selection calculation must be repeated until met process requirements.