Hydraulic direct-acting pressure relief valve YF06-09

Overflow valve and safety valve are two different names when overflow valve plays the role of overflow pressure stabilizing and pressure limiting protection. When overflow valve plays the role of overflow pressure stabilizing, it is called overflow valve, and when it plays the role of pressure limiting protection, it is called safety valve. How to distinguish? In the speed regulation system of the constant-displacement pump, because the oil supply flow of the pump is constant, when the flow is regulated by the throttle valve (throttle speed regulation process), the excess flow overflows from the overflow valve and returns to the oil tank. At this time, the overflow valve plays the role of regulating the system pressure on the one hand, and it plays the role of overflow pressure stabilization when the throttle valve regulates the flow, and the overflow valve is open (normally open) in this kind of work process. In the variable displacement pump system, the speed adjustment is realized by changing the flow rate of the pump. In this process, there is no excess flow from the overflow valve, and the overflow valve does not open (normally closed). Only when the load pressure reaches or exceeds the set pressure of the relief valve, the relief valve opens and overflows, so that the system pressure does not rise any more, which limits the maximum pressure of the system and protects the hydraulic system. In this case, the relief valve is called a safety valve. From the above analysis, it can be seen that in the speed control circuit, if it is a constant pump oil supply system, the overflow valve plays the role of overflow and pressure stabilization, and if it is a variable pump oil supply system, the overflow valve plays the role of pressure limiting protection and is used as a safety valve.