Development and performance test of fine manipulation environment control for Oolong tea vibrating fine manipulation equipment

Abstract: Fine manipulation is the key step during the Oolong tea process. The aroma and taste of Oolong tea were brought out from the step which is repeatedly and alternately rocking and airing. The traditional fine manipulation of Oolong tea is "rocking and airing in different place" with air-conditioning in south Fujian. The process by which tea leaves are put into a mechanical cylinder by turns is called the rocking technique. Then tea leaves are laid into a sieve in an air-conditioned room in what is called an airing technique. The traditional fine manipulation wastes much labor consumption and the3 working posture was difficult to adapt with the spreading and moving of leaves by workers due to the need to carry out the rocking and airing techniques in different place. A larger area and more energy were wasted in the air-conditioning room, and conditions are difficult even.In order to solve those problems, new vibrating fine manipulation (VFM) equipment was developed. The equipment has the combined capability of rocking, airing and environment control techniques. It consisted of the power system, vibrating device, and environment control system. The power system consisted of the power source and eccentric, which could provide driving force to vibrating tea leaves. The vibrating device was composed of a vibrating basket, including a vibrated grid and the static cabinet. Moreover, it could provide spaces for vibrating and airing. The environment regulation system consisted of temperature and humidity adjusted devices including new wind installation and air pipelines, which could provide suitable environmental conditions for the fine manipulation process.The environment regulating performance test of the equipment (ZQ) was investigated with the Tieguanyin variety in spring and summer. The study used the traditional fine manipulation technique with air-conditioning (CK) as a check in south Fujian. ZQ1-Vibrating and airing all selected air conveying high gear. ZQ2-Vibrating selected air conveying high gear, and airing at low. ZQ3-Vibrating and airing all selected air conveying low gear. The results showed that it could effectively control the environment parameters. The velocity of the airflow was controlled at 0.46-0.64 m/s between the tea layers, according to breeze requirements (0.5 m/s).Meanwhile the air temperature was regulated between 22℃ and 24℃. It was significantly lower than the temperature of the natural fine manipulation environment in spring (P＜0.05). Moreover air relative humidity was regulated between 60% and 80%. It was significantly lower than the humidity of the natural fine manipulation environment in spring (P＜0.05). CO2 volume fraction was controlled between 300 and 400 μl/L. It was significantly lower than the air-conditioning fine manipulation environment in summer (P＜0.01).The results showed that the equipment takes advantages of working posture comfort, labor and energy saving. The quality of vibrating fine manipulation raw tea was significantly better than the traditional tea (P＜0.01). In conclusion, the working posture discomfort of six is only 1/3 in contrast with the traditional method. Then labor and energy consumption with the new equipment is only 1/2 in contrast with the traditional method. The results could provide the technical basis for continuous, clean, standardized processing of Oolong tea.