Developement of Analysing System for Characteistics of Electrification of Powder Particles

为了控制粉末带电特性，对接触电势差(CPD)的测量进行分析是非常重要的。本实验室提出的改进的Kelvin Zisman法是目前测量接触电势差最实用的方法。在测量CPD时，存在一些问题。首先，CPD受环境条件的影响，例如湿度和室温。对于电导率较小的样品，由于需要较长的电荷松弛时间，很难测量多种样品的CPD，本研究的目的是研制一种可以控制室温和相对湿度，同时测量多种样品的接触电势差测量系统。此外，我们还分析了摩擦带电与被测CPD的关系。在这一年里，我们研制了接触电势差测量系统。1.测量系统的改进…自动测量系统由于高阻样品需要电荷弛豫，因此对某些类型的样品同时测量是非常有效的。由于这种测量方法需要对微弱的电信号进行分析，因此必须设置电磁屏蔽，以消除外部环境的电噪声，并使内部仪器的机械运动产生的带电降至最低。去年，我们设计并制造了满足上述住宅需求的测量系统。在这一年里，我们反复测试测量，以提高测量的准确性和可信度。2.摩擦带电与CPD的关系我们研究了实际干燥操作过程中的环境条件对颗粒摩擦带电的影响。具体地说，我们研究了在不同环境条件下，铁氧体磁芯表面涂覆硅树脂的颗粒带电与接触电势差的关系。较少

In order to control characterization of powder electrification, it is important to analyze in measuring Contact Potential Difference (CPD). Modified Kelvin Zisman method developed in our laboratory is the most practical one to measure the contact potential difference. There are some problems in measuring CPD. First, the CPD influenced by environmental conditions, for example, humidity and room temperature. For the sample with small electric conductivity, it is difficult to measure CPD of many kinds of samples because long time required for charge relaxation.Purpose of this study is to develop contact potential difference measuring system, which can control the room temperature and the relative humidity and measure some kinds of samples simultaneously. Beside we will analyze the relationship between tribo-electrification and measured CPD.In this year, we prepared contact potential difference measuring system as follows.1.Improvement of the measuring systemThe automatic measuring system … More for some kinds of samples simultaneously is very effective because sample with high resistance requires for charge relaxation. Because this measuring method requires to analyze weak electric signals, we must set electro-magnetic shield to eliminate electric noise of external environment and keep to a minimum generation of electrification by mechanical motion of inner instruments. In last year, we designed and manufactured the measuring system that satisfied the demand of mentioned abode. In this year, we have repeated test measurements to enhance both accuracys of measurements and trust. Besides we have done some repairs to eliminate electric noise.2.Relationship between tribo-electrification and CPDWe have studied influence of environmental condition for actual dry operation process on tribo-electrification of particle. To put it concretely, we investigate between electrification and contact potential difference using the particles with surface of ferrite core coated by silicon resin under different environmental conditions. Less