Study On Drying Technology Of Rhizome Coptidis

Rhizome coptidis is one of the most important export medicinal materials and the annual market demand of it is about 3000t. Shizhu of Chongqing and Lichuan of Hubei are the largest producing area of Rhizome coptidis in the world, and the annual production is about 80% of the world's total. In recent years, after the implementation of good agricultural practices (GAP) and the Promotion of the local government, the scal of planting Rhizome coptidis is becoming more and more biger, and the benefit of planting Rhizome coptidis becomes the pillar of the local economy.Even there are many improvement in planting of Rhizome coptidis, the drying methord which needs hevey workload is a big problem. In the current drying methord, it is very hard to control the drying quality and removing the beards overgrowing the boady of Rhizome coptidis. There hardly have any Literatures or papers about drying techonology of Rhizome coptidis, and the local people have different opinions on the Rhizome coptidis drying. So study on the drying of Rhizome coptidis is very significant.In connection with these problems, this article take experimental researchs to get the best drying techonology and reasonable parameters on removing beards. The conclusion form the study listed as follows:(1) Draft the Evaluation criteria of drying quality of Rhizome coptidis.(2) Experiments were taken in the condition of different temperature with zero wind velocity, and get the drying curve at different temperature, from the regression analysis of the test data, it can be find that when the temperature is between 50℃to 70℃, the drying quality is best.(3) Have experiment study when the wind velocity is 3.5m/s and the temperature at 50℃,60℃and 70℃, get three drying curve, from the regression analysis of the test data, it can be find that when the temperature is 60℃the drying quality is best.(4) At the same temperature, the more bigger of the wind velocity, the drying velocity is more faster.(5) In order to find the solution of removing beards, Orthogonal experiment were taken in a home-made platen. The three orthogonal factors are the shape of platen, the roating speed of the platen, and loading capacity. the shape of platen have two levels which are screen mesh shaped platen and screw thread shaped platen, the roating speed have two levels which are 20rad/min and 40rad/min, loading capacity have two level which are 1/2 of the capacity of the platen and 2/3 of the platen. from the Orthogonal experiment it can be find that the shape of platen have a most outstanding influence on the quality of removing beards, the roating speed have a second effect, and the loading capacity have a third effect. And it also can be find that the best parameters for removing beards is carring the screen mesh shaped platen, the roating speed is 20rad/min, and loading capacity is 1/2 of the capacity of the platen.(6) Referring to the result of study, a drying machine were designed the type is 5HHL-0.2, and some experiments were taken to test and verify the former conclusion. From the experiments, it can be find that the conclusion is right, and very useful to desiging drying machine.In a word, the drying techonology at the zero wind velocity is helpful imorving the tranditional drying of Rhizome coptidis, the drying techonology at 3.5m/s velocity is helpful designing Rhizome coptidis drying machine. Achievement will fill in the blank of the Rhizome coptidis drying techonology, and can solve the problem of Rhizome coptidis drying,and boost the economy of shizhu and lichuan.