生鲜食品包装机气力式超薄自粘膜横封装置设计与试验

Design and Experiment on Pneumatic Transverse Sealing Device for Ultrathin Self-adhesive Film of Fresh Food Packaging Machine

为解决气力式超薄自粘膜横封装置结构复杂、稳定性差等问题,以现有生鲜食品包装机为平台,设计了一套生鲜食品包装机气力式超薄自粘膜横封装置。该装置由立式输送带、前后平行布置的两个上风盒、下折膜机构、切断机构和无动力托辊等组成,其中下折膜机构包括下风盒、滚轮、气缸等,利用气力和机械结构的复合运动,可较好地完成超薄自粘膜横封作业。构建了横封作业过程中包装物料与横封部件的力学模型,利用Fluent软件对其关键部件下风盒进行结构优化分析,得到最优参数为:下风盒进风口位置和水平方向出风口位置对称布置,风腔高度14 mm、水平出风口直径3 mm、水平出风口个数10个。以后上风盒出风口压强、下风盒水平出风口压强、下折膜机构与包装盒底部折膜间距为试验因素,以托盘后部横封率为试验指标进行了正交组合试验。经试验和结果分析,得到最佳参数组合为:后上风盒出风口压强113.3 Pa、下风盒水平出风口压强85 Pa、下折膜机构与包装盒底部折膜间距-3 mm。经试验验证,最佳参数组合下横封率为99%,横封平整、美观,满足包装机横封作业要求。

In order to solve the problems of complex structure and poor stability of transverse sealing device for ultrathin self-adhesive film,a set of pneumatic transverse sealing device based on the existing fresh food packaging machine was designed,which can complete the transverse sealing problem of ultrathin self-adhesive film.And the device completed the transverse sealing operation through the cooperation of six main mechanisms,including vertical conveyor,two up wind boxes arranged in parallel in front and back,cutting mechanism,unpowered idlers and lower folding mechanism which was composed of rollers,a cylinder and a lower wind box,which combined movement of pneumatic and mechanical structure to complete the transverse sealing operation.Then the mechanical model of packaging materials and transverse sealing device were established during transverse sealing process.After that,the structure of the lower wind box which was the key part of device was analyzed by Fluent software.The optimal parameters of the lower wind box were obtained as follows:the position of the air inlet and air outlet in the horizontal direction was symmetrically arranged,the height of the air cavity was 14 mm,the size of outlet of the lower wind box was 3 mm in diameter,and the number of outlets was 10.Furthermore,aiming to obtain the best parameters of the rear transverse sealing,the outlet pressure of the rear up wind box,the pressure of the horizontal air outlet of the lower wind box,the distance between the lower folding mechanism and the bottom of the packaging box were chosen as the experimental factors,and the transverse sealing rate was selected as the experimental index.Through the experimental research and the result analysis,the optimal aggregative index could be obtained under the condition that the outlet pressure of the rear up wind box was 113.3 Pa,the pressure of the horizontal air outlet of the lower wind box was 85 Pa,the distance between the lower folding mechanism and the bottom of the packaging box was-3 mm.By verification of experiment,the maximum value of the transverse sealing rate was up to 99%,and the transverse sealing effect was flat and beautiful,which indicated that pneumatic transverse sealing device could satisfy operation demand of the fresh food packaging machine.