罐头杀菌冷点温度和F值测定系统的设计

在罐藏食品工业中,测定罐头冷点温度和计算杀菌F值一直是一个非常重要的问题。本设计以比奇洛杀菌理论为数学模型,开发了一套基于PC机的可编程开环数据采集系统对罐头的冷点温度进行连续采集并计算出杀菌过程中累计的F值,供在线监视或作为制定生产工艺的参考数据。系统硬件由温度传感器、数据采集仪、PC机、专用安装附件组成。温度传感器的探头被固定在冷点位置上,由数据采集仪通过RS-232串行通信方式将信号传给PC机做进一步处理。PC机的应用程序采用LabVIEW编写。该装置具备数据接收、F值计算、实时曲线绘制和数据保存的功能。实罐试验取得的测试数据表明整套系统可用来有效地演示或在线监视罐头食品杀菌过程中的温度变化。

A Design of Cold Spot Temperature Measurement and F Value Calculation System for Can Sterilization

According to W D Bigelow's sterilization theory, a programmable DAQ system based on PC (Personal Computer) open loop was built to provide continuous measurement of cold spot temperature and accumulate its F value during can sterilization process. The hardware of the system consisted of a temperature sensor, a DAQ instrument, a PC and some other fittings. The probe of the sensor was fixed on the cold spot and thus, the DAQ instrument brought the temperature message to the PC for further processing via RS-232 serial communication. The designed fittings involved a sensor connector nut, a sensor protection tube, a lock nut and packing glands, which could help to introduce the probe into the product, make the probe more stable and maintain the seal during sterilized processing. The specific application program was developed in LabVIEW environment. It could function as data receiving, F Value calculation, real time curve drawing, data saving and outputting. Experiments showed that the whole system can be applied to determine and monitor the temperature changes on-line in canned food sterilization; the system also can offer an off-line reference data for formulating process parameters.