What is the difference between Pressure Reducing Valve, Counterbalance Valve and Relief Valve?

1.Pressure reducing valve

(1)Function: Used to reduce the fluid pressure in the system to a lower stable pressure.

Working principle: Control the flow rate by adjusting the opening of the valve to achieve pressure reduction.

(2)Application Scenarios: Systems that require stable pressure output, such as hydraulic tools, hydraulic presses, etc.

Mainly used to reduce pressure and ensure that the pressure in the pipeline remains within the normal range. It reduces the pressure loss caused by the liquid passing through a narrow gap by adjusting the outlet pressure to be lower than the inlet pressure, thereby playing a role in reducing pressure and stabilizing pressure. Pressure reducing valves can be divided into direct and pilot types according to different pressure regulation requirements, and further subdivided into pressure reducing valves, differential pressure reducing valves, and proportional pressure reducing valves. ‌ In hydraulic systems, pressure reducing valves are often used in situations where multiple actuators require different working pressures. By connecting pressure reducing valves in series on branch oil lines, each actuator can obtain a suitable working pressure. ‌

2.Counterbalance valve (also called load holding valve or hydraulic lock)

(1)Working Principle: It combines the functions of a check valve and a pilot relief valve to keep the load stable by controlling the reverse flow of oil.

(2)Application Scenario: It is mainly used in systems such as lifting machinery that need to keep the load in a stable position.

A pressure valve that performs different controls according to the pressure of the gas circuit. It can use different or the same pressure as a control signal to automatically connect or cut off a certain oil circuit and control the actuator to operate in a certain order. The function of the balance valve is to realize the sequential control function of the action in the hydraulic system: keep the load stationary at any position, prevent the load from moving due to pressure changes, and allow the speed to remain stable when the load changes.

3.Relief valve

(1)Working Principle: When the system pressure reaches the set value, the valve opens and the pressure oil flows back to the tank or is discharged.

(2)Application Scenario: Systems that require overload protection, such as hydraulic cranes, excavators, etc.

Also known as a safety valve or a pressure-limiting cut-off valve, it is mainly used for pressure limiting and safety protection. It overflows the corresponding liquid of the hydraulic system through the valve port, adjusts the system working pressure or limits the maximum working pressure of the system, and prevents the system working pressure from overloading. The overflow valve is required to have good static and dynamic characteristics, including pressure-flow characteristics and rapid response capabilities. Function: Protect the system from damage caused by excessive pressure and maintain the system pressure within a safe range by releasing excess pressure.

Summary

Functional Purpose: pressure reducing valve is used to reduce pressure, balancing valve is used to keep load stable, and overflow valve is used for pressure protection.

Working Principle: pressure reducing valve reduces pressure by adjusting flow, balancing valve stabilizes load by controlling reverse oil flow, and overflow valve protects system by releasing pressure.

Application Scenario: pressure reducing valve is used in situations where pressure needs to be stabilized, balancing valve is used in situations where load position needs to be stabilized, and overflow valve is used in situations where pressure needs to be prevented from being too high.

Each valve is designed for different needs in the hydraulic system to ensure safe, stable and efficient operation of the system.