一、引言化工生产工艺常常要求两个或两个以上的物料保持一定的比例,自动控制的工作人员就必须组成一个比值调节系统,以满足工艺生产的需要。比值调节系统通常可以用比值器、气动配比器、乘法器、除法器等组 I. Introduction Chemical production process often requires two or more than two materials to maintain a certain proportion of automatic control of the staff must be composed of a ratio adjustment system to meet the needs of process production. Ratio adjustment system can usually be used ratioer, pneumatic proportional device, multiplier, divider, etc.