The plate heat exchanger is a high-efficiency heat exchanger formed by stacking a series of metal plates with a certain herringbone shape. The internal water flow of the stainless steel plate heat exchanger is turbulent and is not easy to scale. The scale factor is only 1/3 ~ 1/10 of the tube heat exchanger. Because different corrugated plates are turned upside down to form a complicated flow path, the fluid flows in a three-dimensional rotation in the flow path between the corrugated plates, which can generate turbulent flow at a low Reynolds number (generally Re = 50 ~ 200), and the heat transfer coefficient is generally It is 3 ~ 5 times of the shell and tube type. The heating material stays in the heater for a short time, less internal dead angle, and good sanitary conditions. In the cooling system in the metallurgical process, due to the crystallization of salt in the well water and the deposition of particles such as soil and sand, the growth of organic matter in seawater is prone to fouling. The fluid flowing between the plates is in a highly turbulent flow, which keeps the solids suspended, and the rate of scale formation is much smaller than in the shell and tube type.