Plate heat exchanger is a new type of high-efficiency heat exchanger composed of a series of metal sheets with a certain corrugated shape. Compared with the cooling tower, it has the characteristics of high heat exchange efficiency, small heat loss, compact and lightweight structure, small footprint, convenient installation and cleaning. When applied to intermediate frequency equipment, it is usually used to cool the intermediate frequency power supply separately, because the intermediate frequency power supply has higher requirements on water quality. The intermediate frequency power supply and the furnace body are cooled separately, the water is less likely to be scaled and polluted, and the operation and maintenance costs are reduced.