英语翻译When open- or tandem-center valves are used in circuits

英语翻译
When open- or tandem-center valves are used in circuits requiring pilot pressure to shift the valves,there must be a means of maintaining pressure when the valves are in neutral.One method is to install a backpressure check valve in the tank line.The check valve maintains a backpressure of,say,50 psi.
Low-pressure retraction
Energizing the solenoid extends the cylinder at a maximum pressure corresponding to the main system relief valve setting.De-energizing the solenoid valve retracts the cylinder and holds it retracted at the reduced pressure setting of the pilot relief valve.The check valve prevents the pilot relief valve from operating during cylinder extension.
Two relief valves
Using two relief valves in this circuit gives two working pressures.On the up stroke of the cylinder,the low-pressure relief valve limits system pressure.During the down stroke,the high-pressure valve limits maximum press tonnage for doing work.Using the low-pressure relief on the up stroke saves power by supporting the cylinder with low-pressure fluid.
Reduced pressure
In a system with only one pump,reduced pressure for one branch of the circuit can be obtained with a pressure-reducing valve.This circuit is typical for a welder,which requires high clamping force to be set by the relief valve and reduced force on 翻译好的话加分啊 ,

当开放或纵排中心阀门用于要求试验压力的电路转移阀门时,必须有维护压力手段,当阀门在中性时.一个方法将安装反压单向阀在坦克线.单向阀维护50 psi反压.
Low-pressure收缩
Energizing螺线管延伸圆筒以最大压力与主系统泄压阀设置相应.丧气电磁阀缩回圆筒并且拿着它被缩回在试验泄压阀的订正气压设置.在圆筒引伸期间,单向阀防止试验泄压阀经营.
Two泄压阀
Using二在这条电路的泄压阀给二个工作压力.在圆筒的冲程,低压泄压阀限制系统压力.在下来冲程期间,完成的工作高压阀门极限最大新闻吨位.使用在冲程的低压安心通过支持与低压流体的圆筒节省力量.订正气压的
In与一个泵浦的一个系统,订正气压为电路的一个分支只可以获得与一个减压的阀门.这条电路为焊工是典型的,要求夹紧力量将设置由泄压阀和减少的力量的上流