Rexroth Pressure Control Valve Applications & RFQ | Nabor

Rexroth Pressure Control Valve Applications and RFQ Checklist

Choosing a Rexroth pressure control valve usually starts with one practical question: what exactly needs to happen to the pressure in the hydraulic circuit?

In some machines, the valve is there to protect the system from excessive pressure. In others, it keeps one branch of the circuit at a lower pressure, controls when a second operation begins, or allows pressure to change according to an electrical command. Those applications may all involve pressure control, but they do not call for the same valve.

For an engineer or purchasing team, identifying that circuit function first is usually more useful than starting with a catalogue number.

Where Is a Rexroth Pressure Control Valve Used?

Pressure control valves are used in different parts of a hydraulic system, and the location often gives the first clue about the required function.

Limiting Maximum System Pressure

A pressure relief valve is commonly used where the circuit needs a defined upper pressure limit. Once pressure reaches the selected setting, the valve provides a flow path intended to prevent pressure from continuing to rise unchecked.

This sounds straightforward, but pressure setting alone is not enough for selection. Flow capacity, mounting style, return conditions and the actual operating duty also matter.

For example, the Rexroth DBDS 20 K1X/315 pressure relief valve listed by Nabor is a screw-in cartridge type. Its product page lists a maximum operating pressure of 400 bar and maximum flow of 250 l/min. Those figures help identify whether the series is worth reviewing, but they do not replace a check of the exact circuit and configuration.

Keeping One Part of the Circuit at Lower Pressure

A machine does not always need the same pressure everywhere.

A clamping function, for instance, may need to operate at a lower pressure than the main hydraulic circuit. In that situation, a pressure reducing valve can be used to control the downstream pressure in that branch.

Here, the useful RFQ information is not simply the maximum system pressure. The supplier also needs to understand the required reduced pressure, expected flow, inlet conditions and how the valve is drained or piloted.

Bosch Rexroth separates pressure reducing valves from pressure relief valve families in its official product selection resources, which is a useful reminder that similar pressure ratings do not mean the valves perform the same job.

Using Pressure to Start the Next Machine Function

Some hydraulic circuits rely on pressure as part of the machine sequence.

A typical example is a circuit where one actuator needs to complete its operation before another one begins. A sequence valve can remain closed until the first part of the circuit reaches the selected pressure, then allow the next hydraulic function to operate.

For this kind of inquiry, the hydraulic schematic often tells more than a photograph of the valve. It shows where pressure is sensed, where flow is going and how the next function is expected to start.

Adjusting Pressure from the Machine Control System

When pressure needs to change during the operating cycle, a proportional pressure valve may be required instead of a manually adjusted valve.

This adds another layer to the selection process. Hydraulic data is still needed, but voltage, command signal, amplifier or on-board electronics may also become part of the specification.

If the existing valve has an electrical connector or proportional solenoid, sending a clear photo of the nameplate and connector arrangement can save considerable back-and-forth during quotation.

What to Check Before Comparing Rexroth Pressure Control Valves

One of the more common sourcing problems is comparing two valves because their pressure ratings look similar. In practice, several other details may decide whether the valve can actually be used in the application.

It is also worth checking what happens on the tank or return side of the circuit. Depending on the valve design, back pressure can influence the effective pressure setting or regulated pressure. That is one reason a pressure valve should not always be evaluated as an isolated component.

When the Part Number Is Available

If the existing Rexroth valve is still installed and the nameplate can be read, start there.

A complete material number or type code usually gives the supplier a much better starting point than a general description such as “Rexroth pressure valve.” Send the complete number rather than only the visible series name.

It also helps to include a photo of the valve as installed. This can reveal the connector, adjustment method, mounting position or other details that may not be obvious from the part number alone.

For another pressure relief valve reference, buyers can review the Rexroth DBDS 6 K1X/400 product page.

What If the Exact Rexroth Part Number Is Unknown?

This situation is common with older equipment, damaged nameplates or machines where the original documentation is incomplete.

In that case, avoid trying to identify the valve only from its appearance. Two valves can look similar while having different pressure ranges, internal functions or interfaces.

A more useful inquiry normally includes:

• clear photos of the installed valve and nameplate area;

• the machine model and application;

• what the valve does in the circuit;

• working and maximum pressure;

• expected flow;

• mounting or cavity information;

• hydraulic schematic, if available;

• electrical information for controlled versions.

This does not guarantee that every unidentified valve can be matched from application data alone, but it gives the technical team enough information to judge what still needs to be confirmed.

Rexroth Pressure Control Valve RFQ Checklist

For a quotation request, the following information is usually enough to avoid the first round of basic clarification emails:

• Rexroth material number: complete number if available

• Valve type code: copy it exactly from the nameplate

• Required function: relief, reducing, sequence or proportional pressure control

• Working pressure: normal operating pressure of the circuit

• Pressure setting: required value or adjustment range

• Flow: expected or maximum flow through the valve

• Mounting: cartridge, subplate, sandwich or other interface

• Fluid: hydraulic fluid type if known

• Electrical data: voltage and control information where applicable

• Quantity: current purchasing requirement

• Destination: useful when delivery terms or freight need to be considered

If the valve is being selected for a new design rather than replaced from an existing machine, attach the relevant part of the hydraulic schematic. That usually gives the supplier more useful context than adding several paragraphs to the RFQ.

From Technical Review to Product Inquiry

Nabor's Bosch Rexroth Valve category can be used to review available Rexroth valve references and prepare a product inquiry.

If you are still at the broader valve-selection stage, the related Bosch Rexroth Hydraulic Valves Buying Guide covers general valve functions, pressure, flow, electrical control and purchasing information. This article stays narrower: it focuses specifically on pressure-control applications and the information needed before requesting a quotation.

FAQ

What does a Rexroth pressure control valve do?

It depends on the valve type. A pressure control valve may limit maximum system pressure, maintain lower pressure in part of the circuit, control a pressure-dependent sequence or adjust pressure through an electrical command.

Is a Rexroth pressure relief valve the same as a pressure reducing valve?

No. Their functions are different. A relief valve is generally used to limit pressure, while a reducing valve is used to maintain a lower pressure downstream in part of the circuit.

Can I select a pressure control valve from the pressure rating alone?

Usually not. Flow, pressure range, mounting, pilot or drain arrangement, circuit conditions and control method may all affect the selection.

What should I send if I need a quotation?

Send the complete Rexroth material number and type code when available. If those are unknown, provide photos, circuit function, pressure, flow, mounting information, electrical data and the hydraulic schematic where possible.

Does tank-line pressure matter?

It can. In some pressure-control arrangements, return-side or tank pressure may influence the valve's effective pressure behavior. The effect depends on the valve design and circuit, so it should be checked rather than assumed.

Prepare the RFQ Around the Actual Circuit

The quickest way to narrow a Rexroth pressure control valve inquiry is to describe the job the valve must perform before comparing individual models.

If a complete part number is available, use it. If it is not, provide the pressure function, operating data, interface and circuit information. That gives the supplier a much clearer basis for reviewing the application and identifying any assumptions that still need to be confirmed before ordering.