Development and performance validation of an automated continuous concentration apparatus

To address the industrial pain points of low automation, excessive manual intervention and poor process controllability in the traditional batch concentration process for traditional Chinese medicine (TCM) extracts, an automated continuous concentration apparatus was developed and its peformance was verified in this study. Adopting a modular design, the apparatus integrates a solvent recovery module, a heating evaporation module, a concentrated liquid detection module, and a central control module,which enables continuous feeding and discharging under negative pressure as well as continuous solvent discharge. Using the water extract of Lonicerae japonica as the model drug, a definitive screening design (DSD) was used to investigate the effects of stirring speed, feeding pump rate, temperature, vacuum degree, and liquid level height on evaporation rate and concentration ratio. Critical process parameters (CPPs) were identified, quadratic polynomial mathematical models were established, and the process design space was calculated and validated. The results showed that feeding pump rate and temperature were the CPPs affecting concentration efficiency; the maximum evaporation rate and concentration ratio achieved in the experiments were 529 mL/h and 2.71, respectively. The coefficient of determination (R²) of evaporation rate model was 0.84, and the R² of concentration ratio model was 0.9519, with the predicted values of the models being in good agreement with the experimental validation results. The apparatus has a material processing capacity of 0.06–3 kg/h and enables stable and controllable continuous operation. This apparatus provides a miniaturized and intelligent experimental platform for the continuous concentration of TCM extracts, and also offers hardware support for the development of continuous manufacturing technology for TCM.