Priority valve: The core of flow control in hydraulic steering systems, function and selection guide

I. Core Working Principle of Priority Valve

The priority valve is a flow control valve in a hydraulic system, typically used in conjunction with the steering gear, connected in series between the hydraulic pump and the steering gear. When the hydraulic pump outputs high-pressure hydraulic oil, the priority valve automatically identifies the flow demand of the steering system and prioritizes supplying sufficient hydraulic oil to the steering gear, ensuring smooth and responsive steering at all times. Excess hydraulic oil is then diverted to the working device circuit (such as lifting, excavating, or loading mechanisms) to meet operational needs.

In short, the priority valve follows a "steering priority, work consideration" control logic. Regardless of whether the working device is in operation, it ensures the flow supply to the steering system immediately, completely resolving issues of uneven flow distribution and steering lag in the hydraulic system. Its advantages are particularly evident under conditions of insufficient pump output flow, such as equipment idling or heavy-load operation, preventing safety accidents caused by insufficient steering flow.

II. Core Functions and Advantages of Priority Valves As the "flow manager" of the hydraulic steering system, priority valves possess four irreplaceable core functions, comprehensively enhancing the performance of the hydraulic system:

Priority Flow Supply: A core function, prioritizing flow to the steering circuit, unaffected by the load of the working device. Steering operation remains consistently sensitive and effortless, without delay or heaviness, improving equipment operation safety.

Stable Flow Regulation: Automatically adapts to changes in oil pump output flow, ensuring a stable output of the required steering flow regardless of pump speed. This avoids steering jerking and vibration caused by flow fluctuations, resulting in smoother operation.

Overload Protection Function: Built-in relief valve structure automatically releases pressure when the steering system pressure exceeds the rated value, preventing damage to components such as the steering gear and cylinders due to overpressure, extending the overall service life of the hydraulic system.

Energy Saving and Consumption Reduction: Precisely distributes hydraulic oil, avoiding flow waste, reducing hydraulic system throttling losses, lowering oil pump load and energy consumption, and adapting to energy-saving and environmentally friendly equipment design requirements.

Highly adaptable: Compact structure, easy installation, compatible with various gear pumps and piston pumps, suitable for different steering gear models, compatible with open hydraulic systems, and applicable to both retrofitting and new installations.

III. Applicable Equipment and Selection Considerations for Priority Valves Priority valves are widely used in various equipment requiring hydraulic steering, including loaders, forklifts, excavators, road rollers, tractors, combine harvesters, golf carts, and special engineering vehicles. Any hydraulic equipment that uses a single oil pump to simultaneously supply steering and working devices requires a priority valve to ensure the steering system operates with priority.

When selecting a priority valve, three core points must be considered to ensure perfect matching with the equipment: First, match the rated flow and pressure of the hydraulic oil pump. The rated flow and pressure of the priority valve must be consistent with the oil pump's output parameters to ensure accurate flow distribution. Second, match the flow requirements of the steering gear. Determine the priority supply flow based on the steering gear model to avoid insufficient or excessive flow. Third, pay attention to the interface specifications and installation method. Select a model consistent with the equipment's hydraulic pipeline interface to simplify the installation process and reduce modification costs. Meanwhile, priority valves with cast housings and wear-resistant valve cores are preferred, offering excellent sealing, wear resistance, and suitability for long-term continuous operation.

IV. Daily Use and Maintenance Techniques for Priority Valves Priority valves are precision hydraulic components. During daily use, avoid hydraulic oil contamination, regularly clean the hydraulic oil circuit, and replace the filter element to prevent impurities from clogging the valve core and causing flow control failure. Avoid prolonged operation under overpressure conditions to prevent valve core wear and seal aging. Pay attention to the inlet and outlet directions during installation; do not connect them in reverse, otherwise the steering system will fail. If heavy steering or uneven flow distribution occurs, promptly check whether the priority valve core is stuck or the seals are damaged, quickly troubleshoot the problem, and ensure normal equipment operation.