Hydraulic valve pilot operated relief valve Balance slide valve RPGC-LAN

Differentiation of flow valves

Distinguish: throttle valve, flow valve, speed control valve

1) Because the main function of the throttle valve and speed regulating valve in the hydraulic system is to adjust the flow of the system or the branch, it is collectively referred to as the flow valve

2) Sometimes the flow valve actually refers to the speed control valve.

3) From the basic formula of pressure flow, the throttle valve only changes the size of the flow area of the valve port, and the controlled flow rate is also affected by the change of the pressure difference before and after it; The speed regulating valve (sometimes directly called the flow valve) adopts or series differential pressure reducing valve, or parallel differential relief valve, which respectively constitute a two-way speed regulating valve (which can be configured in series before and after the actuator, or in parallel in front of the actuator) and a three-way speed regulating valve (which can only be connected in series before the actuator, and can only control a load);

4) Two-way speed regulating valve is generally used for fixed pressure system, due to the load pressure compensation, when the load pressure changes greatly, the control flow is basically not affected; However, it will compensate for excess pressure consumption in the form of pressure loss at the valve port. The excess flow of the system is also consumed in the form of oil heating.

5) The three-way speed regulating valve is an energy-saving system because it has a load adaptation function, that is, the outlet pressure of the pump is only a certain value higher than the load (3-8bar). Often equipped with pilot pressure valve, without another safety valve, can achieve system safety protection. In the plastic machine industry, often on the basis of the three-way valve, the proportional adjustment mechanism of the electro-hydraulic proportional pressure pilot valve and the flow valve is configured to form the electro-hydraulic proportional pressure flow composite control valve, commonly known as the pq valve, which simplifies the structure and saves energy.