型砂水分测量若干关键技术研究

Investigation on the Main Technology for Measuring Moisture in Molding Sand

分析了型砂水分测量3种主流电测方法的原理和特点,针对传统测量方法固有的缺陷,提出了改进设计的思想和测量应用系统。其中,电阻测量采用测频测周电路转换后可以克服对测量范围的限制和测量信号远传质量问题;传统的高频电容测量存在较低的测量水分上限,采用超高频电容方法可以实现全量程测量;基于微波的型砂水分测量与被测型砂的温度、体密度等密切相关,为提高测量精度和测量适应性,采用双参量测量方法。3种改进方法都可以实现型砂水分的实时在线高精度测量。

The principles and characteristics of three main technologies for measuring moisture ot molding sand were discussed and some novel designing ideas and measuring system are proposed in order to overcome the limitation of traditional measuring methods, Through the transformation from resistance measurement to frequency period measurement, the resistance measuring method can overcome the limit of measuring range and the quality of signal remote transmission, By using an ultra frequency capacitance method, the measuring range can be enlarged to fit well the scope of molding sand moisture content, The measuring moisture content in molding sand based on both microwave energy attenuation and microwave phase shift can be realized with high accuracy and without the interruption of the sand density change, and the temperature compensation and nonlinear measurement can be implemented by using intelligent data process such as artificial neural network algorithm. The three modified methods can realize on-line measurement with high precision.