GEA-NUS Pharmaceutical Processing Research Laboratory, Department of Pharmacy, National University of Singapore, 18 Science Drive 4, Singapore 117543, Singapore.
GEA-NUS Pharmaceutical Processing Research Laboratory, Department of Pharmacy, National University of Singapore, 18 Science Drive 4, Singapore 117543, Singapore.
Int J Pharm. 2018 Nov 15;551(1-2):42-51. doi: 10.1016/j.ijpharm.2018.09.005. Epub 2018 Sep 5.
The flow of particulate materials is critical during processes such as mixing, compression and packing. Non-cohesive arching, a feature characteristic of coarse and free-flowing particles, has been studied extensively for silos and hoppers. However, the arching of powders during die fill has received much less attention. In this study, die fill performance of coarse and free-flowing nonpareils was evaluated using a specially designed die filling device in order to investigate the impact of non-cohesive arching during die fill under gravity flow. Through evaluating die fill performance, the arching phenomenon during dynamic conditions of die fill could be captured. Nonpareils with large particle size increased the likelihood of arching and caused poorer die fill performance for narrow orifices. In contrast, die fill in large orifices was generally better with larger particles due to reduced inter-particulate friction. Both particle size and size distribution influenced non-cohesive arching during die fill. Forced feeding did not appear to affect die fill performance and non-cohesive arching. A critical particle size range beyond which die fill performance would decrease, particularly for the narrow orifices, was identified. Findings from this study provided a better insight into non-cohesive arching during die fill.
在混合、压缩和包装等过程中，颗粒物质的流动至关重要。非粘性拱现象是粗粒和自由流动颗粒的特征，已经在筒仓和料斗中得到了广泛的研究。然而，粉末在模腔填充过程中的拱现象却受到了较少的关注。在这项研究中，使用专门设计的模腔填充装置评估了粗粒和自由流动的非晶形颗粒的模腔填充性能，以便研究在重力流条件下模腔填充过程中非粘性拱的影响。通过评估模腔填充性能，可以捕捉到动态条件下模腔填充过程中的拱现象。粒径较大的非晶形颗粒增加了拱的可能性，并导致较窄孔口的模腔填充性能较差。相比之下，由于颗粒间摩擦减小，较大的颗粒通常在较大的孔口中的模腔填充性能更好。颗粒大小和粒度分布都会影响模腔填充过程中的非粘性拱。强制进料似乎不会影响模腔填充性能和非粘性拱。确定了一个临界粒径范围，超过该范围，特别是对于较窄的孔口，模腔填充性能会下降。这项研究的结果提供了对模腔填充过程中非粘性拱的更好理解。
