Only by simultaneously increasing the surface thermal coefficient of the hot and cold sides of the plates, reducing the thermal resistance of the scale layer, selecting plates with high thermal conductivity, and reducing the thickness of the plates, can the heat transfer coefficient of the heat exchanger be effectively improved.　  

1. Improve the surface heat transfer coefficient of the plate

Because the corrugation of the plate heat exchanger can cause the fluid to generate turbulence at a small flow rate, a higher surface heat transfer coefficient can be obtained. The surface heat transfer coefficient is related to the geometric structure of the plate corrugation and the flow state of the medium. The waveform of the plate includes herringbone, straight, spherical and so on. After years of research and experimentation, it is found that the herringbone plate with triangular corrugated cross-section has a higher surface heat transfer coefficient, and the greater the angle of the corrugation, the higher the flow velocity of the medium in the flow channel between the plates, and the greater the surface heat transfer coefficient .

 2. Reduce the thermal resistance of the dirt layer

The key to reducing the thermal resistance of the fouling layer of the heat exchanger is to prevent the plates from fouling. When the fouling thickness of the plate is 1mm, the heat transfer coefficient is reduced by about 10%. Therefore, care must be taken to monitor the water quality at the hot and cold ends of the heat exchanger to prevent the plates from scaling and prevent debris in the water from adhering to the plates. In order to prevent water theft and corrosion of steel parts, some heating units add chemicals to the heating medium. Therefore, attention must be paid to water quality and viscous chemicals that cause debris to contaminate the heat exchanger plates. If there are viscous debris in the water, special filters should be used for treatment. When choosing medicaments, it is advisable to choose non-sticky medicaments.

3. Use plates with high thermal conductivity

The plate material can choose austenitic stainless steel, titanium alloy, steel alloy, etc. Stainless steel has good thermal conductivity, with a thermal conductivity of about 14.4W/(mk), high strength, good stamping performance, and is not easy to be oxidized. The price is lower than titanium alloy and copper alloy, but its resistance to chloride ion corrosion is poor.

4. Reduce the thickness of the plate

The design thickness of the plate has nothing to do with its corrosion resistance, but is related to the pressure-bearing capacity of the heat exchanger. Thicker plates can improve the pressure-bearing capacity of the heat exchanger. When the herringbone plate combination is adopted, the adjacent plates are turned upside down and the corrugations are in contact with each other, forming a dense and evenly distributed pointing point. The corner and edge sealing structure of the plate has been gradually improved, so that the heat exchanger has a good pressure bearing. ability. On the premise of meeting the pressure-bearing capacity of the heat exchanger, the thickness of the plate should be as small as possible.