罗茨真空机组预抽阶段的抽气特性比较研究

针对罗茨泵真空机组在启动预抽阶段的三种工作模式——旁通式、直通式和变频式,分别建立了简化计算模型,推导得出罗茨泵进入正常稳态工作之前罗茨机组的有效抽速计算公式,以及被抽容器的抽气时间计算方法.通过一个计算示例,对比得出了三种不同启动预抽方式的压力-时间曲线,结果表明,直通式、旁通式、变频式工作模式下容器的抽气时间依次减...

Comparative Study on Pumping Characteristics of the Roots Vacuum Unit in Start-up Process

In view of the three working modes of the Roots vacuum pump unit in the start-up process,namely bypass mode,straight through mode and frequency conversion mode,the simplified calculation models are established respectively.The effective pumping speed calculation formula of the Roots vacuum pump unit are derived before the Roots pump enters the normal steady-state operation,as well as the calculation method of the pumping time of the pumped container.Through an example,the pressure time curves of three different start-up modes are obtained.It is proved that the pumping time of the container decreases in turn under the working modes of frequency conversion,bypass and straight through,and the frequency conversion start-up mode can save 46.58%of the pumping time compared with that of the straight through start-up mode.