Design Of Continuous Equipment Of High-pressure Infiltration Puffing For Fruits And Vegetables

Fruits and vegetables are high in nutritious value.Various vitamins, enzymes and plant fiber which are contained in its content are good to the human health.Our country is a large agricultural country in production and consumption, the resource of fruits and vegetables rank first around the world. In recent years, the industries of fruits and vegetables are developing rapidly. Since 2011, the total output of vegetable has exceeded that of grain, vegetable become China's first major agricultural product, the industry of fruit and vegetable become pillar industry of China's agriculture. But due to improper method in storage and transportation, the loss of fruits and vegetables is bigger, which causes massive waste of resources. Therefore, the research and development of deep processing technology on fruits and vegetables are of vital significance to improve the utilization rate of fruit and vegetable resources, to increase the profits of industry and to promote the sound development of industry. The technology of air flow puffing drying at low-temperature and high-pressure is a new kind of fruit and vegetable processing technology which is emerging in recent years. For the products after puffing drying have low fat, no additives and crisp taste, at the same time they can well keep the original nutrients in vegetables, the processing technology has drawn greater attention by all of us.Based on puffing drying technology at low-temperature and high-pressure as the research object, this article summarizes the research progress about the technology at home and abroad in recent decades. In view of the shortcomings in existing puffing technology and equipment, the improvement scheme is put forward for improving the quality of the product, increasing production efficiency and energy utilization.To improve the production technology, the scheme of infiltration puffing by high-pressure nitrogen is proposed. The inspiration comes from the shelling technology by gas burst. Under high pressure, nitrogen molecules can slowly seep into the organization through the pores of fruit and vegetable, and keep theenvironment of high pressure for some time, quickly release the pressure, then puffing process has been completed because of the internal-external pressure difference of fruit and vegetable and retardation of pores. To test and verify the feasibility of new technology, corresponding test platform is set up with apple slices as raw materials. The test results show that the technology of infiltration puffing by high-pressure nitrogen can realize puffing process on apple slices.Through single-factor experiment, process operating parameters are preliminary established. After quadratic orthogonal rotation combination experiment, the quadratic regression equation model is established for puffed differential pressure, puffing temperature and vacuum drying time to water content, recovery ratio, swelling degree. The analysis results show that the mathematical model is reliable. The influence rule of the interaction of operating parameters to the product quality is obtained through response surface analysis. Finally, the best values of process parameter for infiltration puffing have been obtained by parameter optimization.To improve puffing equipment, the scheme for a kind of continuous infiltration puffing equipment is proposed in view of existing batch equipment's problems for long production cycle and low output. This paper briefly expounds the working principle of new type of continuous puffing equipment, the total output of continuous equipment is defined. According to the values of operation parameter determined in the previous test, the continuous equipment has been designed, including the design and calculation of expansion shell, rotating material box, transverse and radial seal and vacuum tank and bearing, and selection of transmission mechanism etc.The finite element analysis of expansion shell, rotating material box and bearing on continuous equipment have been carried on by ANSYS software.According to the results of the analysis, the position for maximum equivalent stress of shell locates at the discharge hole. Its value is less than the allowable stress of material and the value of maximum deflection is smaller. Stress and strain analysis of rotating material box with baffle of different thickness have been carried on. The results show that when the thickness is 20 mm or 30 mm, the value of maximum equivalent stress exceeds the allowable stress of material and the maximum deflection is too large. And when the thickness is 40 mm or 50 mm,structural strength meet the requirements. Considering the weight of the equipment, the best thickness is 40mm; The result of force analysis for improved bearing shows that the value of maximum stress and deflection are smaller, the structural strength meet the requirements.