冷冻干燥工艺程序自动化研究

Study on automation in freeze-drying process program

对冷冻干燥过程中的传热传质进行分析,依据冻干塌陷原理,编制具有自适应性的逻辑公式,设置物料塌陷温度、真空仓压力和过热度等输入参数。在BSNFD05冻干机上进行测试,结果表明,在冷冻干燥过程中,按照PLC中的自适应逻辑,以髙精量传感器采集的加热板温度、真空仓压力和冷阱(捕水器)过热度为控制量,通过三通调节阀、真空挡板阀和供液电子膨胀阀等执行机构,实现在冷冻干燥过程中按照逻辑判断、不断修正自动形成工艺程序,最终完成冷冻干燥。

Heat and mass transfer in freeze-drying process is analyzed. Based on the freeze-drying collapse principle, the logic formula with adaptability is established and in- put parameters including material collapse temperature, vacuum chamber pressure and o- verheat are set. The test is conducted on BSNFD05 freeze-dryer. The testing results show that according to the adaptability logic in PLC, the logical judgment and auto-correction in the freeze-drying process can be achieved by controlling the heating plate temperature, vacuum chamber pressure and overheat of the cold trap （water-catcher） which are collect- ed from the high-precision sensors. The three-way regulating valve,vacuum baffle valve, supply liquid electronic expansion valve and some other actuators are used for execution.