| Mill is one of the important equipment in modern flour, roller in mill by crushing, shearing the material, to broke the material. Because there are large of pressure between two pairs of rollers, friction and extrusion will produce large amounts of heat between material and rollers, Grinding surface temperature can reach 60 to 80 ℃ after long time work. The roller temperature is too high, not only will burnt the material stuck on the roller, reduce the shearing of the material, but also increase power consumption and shorten the life of the grinding rolls. And high-temperature materials in the protein will change and gelatinized starch, greatly reduce the quality of flour. So the roller overheating problem must be solved.To solve the problems, Wu Wenbin, Yang Junwei, Li Dongliang et al. combined the heat pipe and grinding roller, designed a rotating heat pipe cooling roller. Due to the heat pipe type cooling grinding roll structure and heat radiating area insufficient, heat pipe cooling effect is not ideal, and the grinding roll structure change has brought a lot of difficulties to the grinding roller production. This article based on the heat pipe cooling roller of predecessor studies, improve structure, the grinding roller and the heat radiating part, redesigned the related parameters of cooling roller, to make the manufacture and installation is convenient, more conducive to industrial scale production. And through the vacuum test, verified the rationality and feasibility of structure.The main research work are as follows:1. Using heat conduction knowledge analysis of heat transfer process and the thermal resistance of each process, in the design process to try to reduce the large thermal resistance, so that the roll is more conducive to heat transfer.2. In order to reduce the thermal resistance, increase the small hollow roller diameter based on the 100 mm to150 mm, roller shaft diameter of 28 mm to 32 mm, using finite element software analyze the stress strain of the roller body diameter, get the roll body stiffness and strength meet the application requirements, and enterprise survey in grinding roller production, the roller body 150 mm aperture conforms to the finale conditions(the roller diameter too large will lead to the roller crack).3. According to the transmission quality factor compatible principle and working fluid calculation, selecting water as working medium in heat pipe. By using the Streltsov formula to calculate the refrigerant filling quantity of the best is 4.79%.4. In order to have a better heat dissipation, reset the fin size and installation, to make it more conducive to installation and disassembly, accord with the actual production.5. Design the type sealing structure of heat pipe roller, selection of heat pipe vacuum method, design of vacuum experiment, verify the rationality and reliability of the sealing structure. |
