During selecting the spring return actuators , we can choose the more reasonable and more economical actuators , if we konw the different torque needed by the valve working at opening , operating and closing 在单作用执行器的选配过程中,如果能够了解阀门在开启、运行和关闭时的扭矩分配,我们就可以更加经济、更加合理地选配执行器。