Hydraulic balance valve Excavator hydraulic cylinder valve core CBGA-LBN

Working principle of the relief valve

Relief valve is a kind of oil pressure control valve, which mainly plays the role of constant pressure overflow, pressure regulation, system reversing and safety protection in oil pressure equipment.

Relief valve principle: In the quantitative pump throttling regulation system, the quantitative pump provides a constant flow rate, and when the system pressure is reduced, the flow demand will be reduced. At this moment, the relief valve opens the pressure regulating and reducing valve to make the excess flow overflow back to the tank and ensure the inlet pressure of the relief valve.

In a fixed pump throttling control system, the fixed pump provides a constant flow. When the system pressure is reduced, the flow demand will be reduced. At this moment, the relief valve is opened, so that the excess flow flows back to the tank pressure regulator and pressure reducing valve, to ensure that the relief valve inlet pressure, that is, the pump outlet pressure is constant (the valve port is often opened with pressure fluctuations).

The difference between relief valve and pressure reducing valve

The relief valve is to avoid system overspeed and ensure safety. The pressure reducing valve is to increase the system pressure under the premise of ensuring that the system does not lack phase.

1, the pressure reducing valve is mainly used to reduce the pressure of a branch line of the oil pressure system, so that the branch pressure is lower and stable than the main oil pressure, in the range of setting pressure, the pressure reducing valve is also turned off like the relief valve. And with the decrease of the system pressure, when the pressure set by the pressure reducing valve is reached, the pressure reducing valve is opened, and part of the oil will return to the tank (at this moment, there is a certain pressure of the oil back to the tank, the water temperature of the tank will rise), the hydraulic pressure of this branch will not rise. It plays the role of reducing pressure and stabilizing pressure on this avenue! The relief valve is different, and it is installed at the outlet of the pump to ensure that the overall pressure of the system is stable and does not overpressure. Therefore, he has the role of safety, pressure regulation, pressure regulation and so on!

2, the relief valve is usually in parallel in the system of the mountain road to play the role of pressure regulation, pressure regulation and pressure reduction, and the pressure reducing valve is usually in series on a road to play the role of pressure reduction and pressure preservation road!

3, the relief valve is normally closed, but also when the system overpressure action; The pressure reducing valve is open and depressurizes through a narrow channel.

4, the role of the relief valve is pressure regulation, overflow, overload protection. The pressure reducing valve reduces the pressure, and the pressure in a certain part of the oil pressure system is reduced. Different uses. Therefore, it cannot be replaced.