1、 Do hydraulic gear pumps have to be equipped with relief valves?

Gear pump is a very common hydraulic pump, and its output flow rate is related to the pump speed and pressure difference. In general, gear pumps do not need to be equipped with relief valves. Because when the load increases, the output flow rate of the pump decreases, thereby reducing the system pressure, it is not easy to encounter situations where the pressure is too high.

However, in some special cases, the output flow of the gear pump is prone to violent fluctuations, such as when the load in the hydraulic system suddenly decreases or disappears, and the output flow of the pump instantly increases. At this point, if an overflow valve is not installed, the hydraulic system will be subjected to excessive pressure shock, leading to system failure.

In addition, under some high-temperature and high viscosity conditions, the oil in the hydraulic system will become viscous or increase in viscosity, which will also affect the output flow rate of the hydraulic pump. If there is no relief valve in the hydraulic system, it is easy for the gear pump to overheat due to high pressure.

Therefore, whether the gear pump must be equipped with an overflow valve depends on the specific requirements and working conditions of the hydraulic system. In general, it is not necessary to install an overflow valve; But in some special working conditions, in order to protect the normal operation of the system and hydraulic pump, it is necessary to set up an overflow valve.
 

2、 What is the overflow valve of a gear pump?

Overflow valve is a hydraulic component that has the function of automatically regulating pressure stability. In hydraulic systems, relief valves can be set to open the valve port when the system pressure exceeds the preset value, allowing excess hydraulic oil to flow back to the tank to protect the system from excessive pressure.

In some hydraulic systems with high viscosity, high temperature or high pressure, due to the small output flow of the hydraulic pump and its susceptibility to load, pump jamming, high pressure or other faults may occur. At this point, setting an overflow valve can protect the hydraulic system and hydraulic pump.
 

3. Summary

Hydraulic gear pumps do not necessarily need to be equipped with relief valves, but in some special cases, relief valves need to be installed to protect the system and ensure the normal operation of the hydraulic pump. Therefore, in the design and use of hydraulic systems, it is necessary to fully consider the working conditions and system requirements, and reasonably configure and use hydraulic components to ensure the safe and stable operation of the system.

The above: Analysis of the cause of spline shaft fracture in hydraulic piston pump