Brazing of plate heat exchanger

Brazing of plate heat exchanger, heat exchanger brazing furnace

The plates form an interwall heat exchanger with a heat transfer surface. This type of heat exchanger has compact structure and large heat transfer area per unit volume. The main types are:

Brazing furnace

1. Spiral plate heat exchanger is composed of two parallel metal plates kept at a certain distance. Cold and hot fluids flow in the spiral channel on both sides of the metal plate respectively. The heat transfer coefficient of this heat exchanger is high (about 1 ~ 4 times higher than shell and tube heat exchanger), the average temperature difference is large (because cold and hot fluid can make complete countercurrent flow), the flow resistance is small, not easy to scale; But maintenance is difficult. Service pressure shall not exceed 2MPa.

2. The flat plate heat exchanger is composed of a certain shape corrugated sheet and sealed gasket, which are interactively superimposed and clamped together by a frame. The cold and hot fluids flow through the flow passage on both sides of the corrugated plate respectively, and transfer heat through the plate. Corrugated plate is usually made of stainless steel, aluminum, titanium, molybdenum and other thin plates with a thickness of 0.5 ~ 3mm. The advantages of plate heat exchanger are high heat transfer coefficient (about 2 ~ 4 times higher than shell and tube heat exchanger), easy to disassemble and wash, and the heat transfer area can be adjusted by increasing or decreasing the number of plates. The operating pressure usually does not exceed 2MPa and the operating temperature does not exceed 250℃.

3. Plate-fin heat exchanger is composed of a heat exchange plate bundle enclosed in a collector box with inlet and outlet of cold and hot fluids. The plate bundle consists of a flat plate and a corrugated fin, which are mutually superposed and brazed. Cold and hot fluids flow through the two sides of the plate for heat transfer, fins increase the heat transfer area, and promote fluid turbulence, and have an enhanced effect on the equipment. The plate-fin heat exchanger has a very compact structure (heat transfer area up to 4400m2/m3), good heat transfer effect and operating pressure up to 15MPa. However, due to its complex manufacturing process, small flow passage and difficult repair of internal leakage, it is limited to clean non-corrosive fluids, such as heat exchangers for air separation.