The total heat transfer coefficient is a parameter used to measure the heat transfer resistance of heat exchanger. Improve the flow rate between the plates, can improve the heat transfer coefficient, but improve the flow rate, will increase the resistance of the heat exchanger, then improve the circulating pump power consumption, so it is not economic. In order to better control the resistance requirements, it is necessary to have certain measures to assist. Today, we will introduce the method of changing the resistance of plate heat exchanger.
1. Multi-process combination can be used to change the resistance of plate heat exchanger. When the flow rate of cold and hot medium is large, multi-process combination can be used. 2, in the plate heat exchanger bypass pipe: when the flow of hot and cold medium is relatively large, can be set up between the inlet and outlet of the large flow side of the bypass pipe, used to reduce the flow into the plate heat exchanger, to reduce the resistance. 3, the use of mixing plate, mixing plate on both sides of the corrugated geometrical shape structure is the same, according to the Angle of herringbone corrugated can be divided into hard plate and soft plate, Angle is generally about 120 degrees for the hard plate, less than 90 degrees, in about 70 for the soft plate, mixing plate hard plate heat transfer coefficient is high, resistance is large, soft plate is the opposite. Therefore, the combination of soft plate and hard plate can form three different flow channels of high, medium and low characteristics, which can meet the requirements of different working conditions. But when the ratio of cold and hot medium is too large, the mixed plate should not be used.
The average flow velocity of the medium in the flow passage of the heat exchanger is appropriate to 0.3~0.6m/s, and the resistance of the plate heat exchanger is appropriate to not more than 100kPa. According to different cold and hot medium flow ratio to choose different forms of equipment.