Abstract:

In toothpaste process, thickeners such as carboxymethyl cellulose and carbomer tend to form agglomerates in high shear mixers (HSMs),which will cause quality problems as well as disturb normal production. To investigate the influence of different operational conditions of HSMs on agglomerates, the image analysis method based on software Photoshop and Image J was applied to measure the area and total count of agglomerates in a HSM. The influence of rotational speeds, circulating number and total energy input was analyzed. The results showed that the at 1700—2600r/min, the areas of about half number of agglomerates are in the range of 0.5—1.5mm². At 1700—2000r/min, as the circulating number increases, the normalized total count fluctuates significantly. At 2150—2600r/min, as the circulating number increases, the normalized total count decreases without fluctuation. The total energy input is key factor that controls the total count of agglomerates and when total energy input reaches 1000kJ, the total count of agglomerates decreases to the minimum value.

Key words: image analysis, distortion correction, high shear mixer, thickener, agglomerate, deagglomeration

摘要：

在牙膏生产工艺中，羧甲基纤维素、卡波姆等增稠剂在高剪切混合器中往往会发生结块而形成团聚体，严重影响产品质量和正常生产。为了研究不同操作条件对高剪切混合器中团聚体的影响，本文采用了Photoshop与Image J联用的图像分析方法，对1700~2600r/min转速范围内高剪切混合器中增稠剂团聚体的面积和数量行了测量，分析了转速、循环次数和总能量输入对团聚体数量和面积的影响。研究结果表明：在1700~2600r/min转速范围内，经高剪切混合器作用后排出的团聚体颗粒的测量面积集中分布在0.5~1.5mm²范围内，约占团聚体颗粒总数的50%；在1700~2000r/min范围内，随着循环次数的增加，归一化颗粒数会出现较大幅度的波动；在2150~2600r/min范围内，随着循环次数的增加，归一化颗粒数平缓下降没有出现波动。总能量输入是影响增稠剂团聚体数量的关键因素，并且当总能量输入达到1000kJ时，团聚体数量降至最低值。

关键词: 图像分析, 畸变校正, 高剪切混合器, 增稠剂, 团聚体, 解团聚