涡流管冷却技术在聚乳酸滤棒切割装置中的应用

Application of vortex tube cooling to polylactic acid filter rod cut-off unit

为解决加热卷烟聚乳酸滤棒切割过程中受热变形问题,基于聚乳酸对温度敏感的材料特性,在滤棒成型机切割装置中加装涡流管对切刀进行冷却,并通过数值模拟分析方法确定涡流管最优工作参数。采用入口压力P_(入口)=0.5 MPa、入口温度T_(入口)=26.85℃的压缩空气作为气源,入口气流经涡流管作用后分为冷热两股气流,当热端出口压力P_(热)恒定为0.07 MPa时,可达到最大制冷效果。以AF-KDF2滤棒成型机组生产的聚乳酸滤棒为对象进行测试,结果表明:采用涡流管冷却切刀后,切刀温度由57.8℃下降至13.1℃,消除了滤棒切口拉丝现象,机组运行速度由50 m/min提升至150 m/min,滤棒圆度和圆周均稳定在工艺标准范围内。该技术可为提高加热卷烟产品质量提供支持。

To solve the problem of thermal deformation during the cut-off process of polylactic acid(PLA)filter rods for heated tobacco products(HTPs),a vortex tube was added to the cut-off unit of filter rod maker to cool the cut-off knife.By numerical simulation,the preferable parameters of the vortex tube were determined:inlet pressure P_(in)0.5 MPa,inlet air temperature T_(in)26.85℃,the air flow leaving the vortex tube is divided into hot and cold streams.When the hot end air pressure P_(hot)is fixed at 0.07 MPa,the maximum cooling effect can be achieved.The vortex tube cooling was tested on an AF-KDF2 filter rod maker.The results showed that the temperature of the cut-off knife was lowered from 57.8℃to 13.1℃,the fibrous tail at filter’s cut end was avoided,meantime,the running speed of the maker was increased from 50 m/min to 150 m/min.The roundness and circumference of the filter rods were stably within the specified limits.This technology supports the improvement of HTP quality.