Brazed heat exchanger is an evolution of detachable heat exchanger, the sealing material is changed from rubber pad to copper, and all the plates are combined together by copper solder. Brazed plate heat exchanger is one of the new equipment in the field of heating and cooling. Brazed heat exchanger does not have sealant pad, all the plates are made of high temperature melted and welded copper foil, the plate has a unique herringbone corrugated design, can make the fluid in low flow rate also achieve the effect of turbulence, heat transfer efficiency is high, brazed plate heat exchanger sizing is usually small, mainly used in high temperature and high pressure, rubber pad can not adapt to the working conditions. It also has certain disadvantages, brazed heat exchanger can not be separated to clean, can not be repaired, the price is slightly higher.