基于近红外技术的绿茶杀青自动控制系统设计与试验

Design and experiment of automatic control in green tea firing process based on infrared spectroscopy

为了解决绿茶杀青中因鲜叶大小、季节差异以及内部含水量不同等因素影响杀青叶质量的问题,设计了杀青自动化控制生产线,采用红外光谱技术对杀青后鲜叶含水量在线精确测量,通过可编程逻辑控制器(PLC)调节投叶量或滚筒转速,从而保证鲜叶杀均杀透。试验结果表明,该系统检测技术和装置具有可靠性和实用性,在线检测误差在2.37%±3.53%范围内。

During the firing process of green tea, the quality of tea is disturbed by the size, season and mois- ture fluctuation and so on. In order to get an accurate moisture content of the test single kernel green tea during the firing process, a kind of online moisture content metering technology and device were developed. The automatic production line was designed, and the water content of leaf was measured online accurately using infrared spec- troscopy. At the same time, leaf weight or roller speed was regulated by programmable logic controller （PLC）, so as to ensure the quality of firing leaves. It is concluded that detection technology and device of the system are of high reliability and practicability, and the detection error online is in the range of 2.37%±3.53%.