DBW Series Solenoid Pilot Relief Valve

Shijiazhuang Laiye Import& Export Trading Co., Ltd. is one of the leading manufacturers and suppliers of dbw series solenoid pilot relief valve in China, also supports customized service. If you're going to wholesale high quality dbw series solenoid pilot relief valve made in China, welcome to get pricelist from our factory.

Avoiding the hidden cost of idle circulation
In most hydraulically powered machines, the pump runs as long as the engine or motor is on. If the machine is waiting, positioning, or between cycles, the pump continues to deliver flow. If the system does not have an unloading function, this flow has nowhere to go but over the relief valve. The oil circulates at full pressure through the valve, which adds heat to the system and draws unnecessary power from the drive. Over a full shift, this adds up. The DBW series interrupts this cycle by opening the main spool to the tank when the solenoid is energized. The pressure drops to a level just enough to overcome line losses, and the pump turns with almost no load.

Using the unloading function in production cycles
The value of this function becomes more apparent in equipment with repeated cycles-injection molding machines, stamping presses, and automated assembly stations. In these systems, there are often intervals when the machine is not producing any work, but the pump is still running. By wiring the solenoid to the machine controller, the unloading function can be activated automatically during these idle intervals. This reduces the average system temperature, increases pump service life, and cuts the energy consumed during each cycle.

Five sizes to match the flow of the circuit
The DBW series solenoid pilot relief valve is produced in five mounting sizes: NG10, NG15, NG20, NG25, and NG30. The NG10 is rated for 250 L/min and is typically used in auxiliary circuits or smaller systems. The NG15 through NG25 sizes handle 500 L/min, which accommodates most mobile and industrial applications. The NG30 is rated for 600 L/min and is used in large central hydraulic systems. Selecting the correct size is straightforward-the valve should match the maximum flow output of the pump.

Selecting the coil voltage
The solenoid coil is available in DC and AC versions, with voltages that match the common electrical standards in mobile and industrial machinery. The DC coils are available in 12V and 24V, and the AC coils are available in 110V and 220V. The coil is wired directly to the control panel, which allows the unloading function to be triggered by a manual switch or automatically by the machine's logic controller.

Set the relief pressure with the manual knob
The DBW series is also a fully functional pressure relief valve when the solenoid is not energized. The manual knob on the pilot stage sets the maximum system pressure. The adjustment ranges are 5, 10, 20, 31.5, and 35 MPa. The operator turns the knob until the system pressure reaches the target value, then locks it in place. The valve holds the system pressure at the set point and protects the circuit from overpressure.

Switching between normal and unloaded states
When the solenoid is energized, the pilot stage is bypassed, and the main spool opens fully. The system pressure drops rapidly to near zero, and the oil flows freely to the tank. When the solenoid is de-energized, the main spool closes, and the valve returns to normal pressure relief operation. This transition is controlled entirely by the electrical signal, which allows the unloading function to be automated or triggered by the operator.

Relief and unloading in one assembly
The DBW series combines two functions into a single valve body. A standard system would require a separate relief valve and a separate solenoid directional valve to achieve the same function. By integrating both into one assembly, the DBW reduces the number of components, simplifies the manifold layout, and reduces the number of potential leak points in the circuit.

Below are the detailed technical parameters for the DBW series, derived directly from the product specifications.

Performance Parameters Table

Mobile machinery and long idle periods
On excavators and wheel loaders, the pump runs continuously as long as the engine is turning. When the operator is waiting for a truck or repositioning the machine, the pump continues to deliver flow. Without a way to unload the system, that flow is forced over the relief valve at full pressure. The oil temperature climbs, and the engine works against an unnecessary load. The DBW series is usually installed in the pressure line between the pump and the main directional valve. The operator can energize the solenoid from the cab during these idle periods, dropping the pressure to near zero and allowing the pump to turn freely.

Industrial presses with automated loading cycles
In industrial press circuits, the pump often runs continuously to maintain clamping or holding pressure. During the loading and unloading phases, the press is not actively working, but the pump is still running against a closed circuit. If the DBW series is integrated into the machine's PLC logic, the solenoid can be energized automatically during these transfer phases. This reduces the heat input to the hydraulic system during each cycle. When the press is ready to cycle again, the solenoid is de-energized, and the system returns to the set holding pressure.

Test benches with emergency dump requirements
High-flow hydraulic test benches have two requirements for the pressure relief circuit: it must protect the system from overpressure during normal operation, and it must be able to drop the pressure rapidly in an emergency. The DBW series meets both requirements with a single assembly. The relief function protects the pump and components during testing. If the operator triggers the emergency stop, the solenoid is energized, and the main spool opens to the tank. The pressure drops in milliseconds, which prevents damage to the test fixtures and the test article.

The DBW series uses a two-stage design, which means the pilot spool and the main spool are the two components that determine its performance. The pilot spool sets the pressure; if its fit with the bore is not precise, the set point will drift. The main spool handles the full system flow, and its sealing edge has to be clean and accurately machined to hold pressure under load. We machine both spools on our own CNC equipment, rather than sourcing them from outside suppliers. This gives us direct control over the fit and surface finish. Each spool is inspected individually before it moves to assembly.

The valve operates at a maximum inlet pressure of 35 MPa. At that level, even a small scratch on a sealing surface can become a leak path. During assembly, we inspect every sealing face on the body and the spools. Once assembled, each valve is tested on a hydraulic bench to confirm that it holds the rated pressure without external leakage. If a valve leaks during this test, it is reworked before it is packed.

We export this series to customers in Russia, Europe, the Middle East, South America, and Asia. Those regions have very different operating conditions-cold climates where oil viscosity rises, and hot, dusty environments where contamination is a constant risk. We have learned that a valve that performs well in a controlled laboratory setting at 35 MPa also has to be able to handle field conditions. The production process is built around that expectation.

Every DBW valve is shipped with protective caps on all ports to keep debris out. Depending on the order size, the valves are packed in export-grade wooden crates or heavy-duty cartons. Installation and adjustment instructions are included with each shipment. For OEM customers, we can also provide CAD models and hydraulic schematics to support integration into new machine designs.

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