对气垫流浆箱自动调节系统的评估

Evaluation of Alternative Headbox Control Systems

本文建立了一个描述造纸机流浆箱的数学模型及其自动调节系统的计算机模拟系统。利用这个模型及模拟系统能对各种流浆箱自动调节系统进行动态模拟和质量评估。对气垫流浆箱的四种不同调节方案,进行模拟及其结果的比较和评估后发现:方案一(用总压控制进浆量,用浆位控制空气流出量)优于方案二(用总压控制空气流出量,而用浆位控制进浆量),方案三(在方案一基础上增加了内溢流)更好;在方案四中,由于加入了浆速一网速比的串级调节系统,能有效地克服网速干扰对浆速-网速比及纸页定量的影响。

A computer simulation model describing paper machine headboxes has been developed. Combining the headbox model with the GEMS simulation system allows dynamic simulation and evaluation of headbox control systems. The simulation results for four air-cushioned headbox control systems are compared. It was found that the control efficiency of Scheme 1, in which total head regulates the stock inflow and level regulates the air outflow, is better than Scheme 2 with the opposite variable pairing. Scheme 3 which adds headbox internal overflow to Schene 1 is best In Scheme 4, an efflux ratio cascade control loop is included to overcome the effect of wire speed disturbance on efflux ratio and basis weight.