Plate heat exchanger is a new type of high efficiency heat exchanger, which is composed of a series of corrugated metal sheets. Thin rectangular channels are formed between various plates, and heat exchange is carried out through plates. Plate heat exchanger is an ideal equipment for liquid liquid and liquid vapor heat exchange. It has the characteristics of high heat exchange efficiency, small heat loss, compact and light structure, small floor area, convenient installation and cleaning, wide application and long service life. The basic structure and operation principle of plate heat exchanger are mainly frame type (detachable type) and brazing type. The plate forms are mainly herringbone corrugated plate, horizontal flat corrugated plate and tumor plate. The main structure of brazed heat exchanger is 1. Plate plate and plate heat exchanger gasket are used to fix the pressing plate. Movable pressing plate, clamping bolt, upper guide rod and lower guide rod are stacked into plate package with channel type. The end plates with connecting pipes are respectively arranged at both ends. The whole machine is made of vacuum brazing. The adjacent channels flow two media respectively. The plates between adjacent channels are pressed into corrugated. The heat exchange of two media is enhanced. In the brazed plate heat exchanger for refrigeration, the flow channel is always more than that of refrigerant. The picture shows a single side flow, some heat exchangers are made of diagonal flow, namely: Q1 and Q3 hold one medium, while Q2 and Q4 hold another medium. All the pictures are screw and bolt structure, which is convenient for field disassembly and repair. The operating principle plate heat exchanger is a new high-efficiency heat exchanger which is made up of metal plates with certain corrugated shape. It is constructed with gasket, pressing plate (movable end plate, fixed end plate) and frame (upper and lower guide rod and front pillar). The plates are sealed and guided by sealing gasket to separate the two fluid channels of cooling / heating, The cold / heat exchange medium flows through each channel respectively, and heat exchange is conducted with the separated plate to achieve the required temperature of the user. Each plate has a hole in the four corners, and the distribution pipe and collecting pipe of the fluid are formed after assembling the plate bundle. After the heat exchange of cold / hot medium, the water is recycled after the return flow from each collecting pipe. Heat transfer principle: wall heat transfer. Single process structure: only 2 plates are not heat transfer - head and tail plates. Picture double flow structure: each process has 3 plates without heat transfer. Picture plate and runner usually have two corrugated plates (L small angle and H angle), so there are three different channels (L, m and H), as shown below: l: small angle picture consists of adjacent small angle plates. The heat transfer coefficient is low and the resistance is small. It is suitable for the case of large flow, weak heat transfer (low specific heat or small temperature difference), such as air heat transfer under environmental pressure. H: The large angle picture is a channel composed of adjacent plates with large angle. The heat transfer coefficient is high and the resistance is large. It is suitable for the case of small flow but strong heat transfer (high specific heat, phase change or large temperature difference), such as: refrigerant phase change heat transfer. M: Channel image is a channel composed of adjacent plates with large / small angle. The heat transfer coefficient and resistance are between H and l channels. L + L = small angle channel picture L + H = mixed channel H + H = picture of large angle channel are selected in these three channels, and the specific working conditions are used to make and select the type. Theoretically, a heat exchanger can be mixed with different types of runner, such as type h followed by M-type. However, in the case of phase change, this will lead to the misallocation of medium between the first H-channel and the last M-channel, so bphe for various refrigeration purposes is not used. The main function of the corrugated plate is to make the fluid turbulent, strengthen the wave of adjacent plates to form contact resistance points, and improve the pressure resistance. Photo note: Chocolate distribution: make the fluid flow evenly through the whole plate, and the pressure drop at a and B is the same, so that the pressure loss here is minimized. The pressure drop is used for effective heat transfer, and the parallel flow Alfalaval invention and creation are allowed, and it has been widely used. As shown in the figure below. Picture parallel flow and diagonal flow: advantages of picture parallel flow: a plate & a gasket, the same plate in the plate group, rotating 180 º It can be used for the two side channel with small spare parts loss. It can meet all functions of diagonal flow completely, and the higher design pressure or the use of thinner plate does not cross the pipe outlet. picture