R900408340 ZDR10DB2-5X/150YM Rexroth stacked pressure reducing valve made in Germany

FAQs for Rexroth ZDR10DB2-5X/150YM Pressure Reducing Valve

1. Q: The model number includes "DB2". How does this "B2" variant differ from the "P2" variant?

   A:​ The "DB2" (or "B2") is a specific performance characteristic code. It defines a predefined relationship between the adjustment screw position, the spool's movement, and the resulting regulated pressure. This "B2" curve differs from a "P2" or "A2" curve in aspects like linearity, the pressure gradient per screw turn, and minimum controllable pressure. For predictable system performance, it is essential to use the valve variant (B2, P2, etc.) specified in your hydraulic schematic, as substituting one for another can lead to incorrect pressure control.

2. Q: This is a 10mm valve. What flow rate can it handle, and how do I know if it's sized correctly?

   A:​ This 10mm valve can handle flows up to approximately 60 liters per minute (L/min). To verify correct sizing, you need to know the maximum flow demand​ of your secondary circuit (the equipment connected to the A port) and the pressure drop​ (difference between the primary P pressure and the desired secondary A pressure). Then, consult the valve's official flow vs. pressure drop curve​ in the datasheet. If your required flow at that pressure drop is on the left side of the curve, the valve is sized correctly. Operating at the far right limit can cause instability and overheating.

3. Q: The valve is described as "stacked." What does that mean for installation?

   A:​ The term "stacked" in this context typically means the valve is a cartridge (screw-in) type​ designed to be installed into a machined cavity within a hydraulic manifold block or valve stack. It is not a standalone, inline valve. Multiple such cartridge valves can be "stacked" or grouped in a single manifold to build a compact, integrated hydraulic control system with common inlet and tank galleries. Installation requires a properly machined cavity according to ISO 7368 size 10 specifications.

4. Q: I need to maintain pressure in a locked cylinder. Will this valve work, or will pressure bleed off?

   A:​ It will function but is not ideal for long-term, zero-leakage holding. This direct-acting valve has an inherent internal leakage path from the P port to the T port​ even when the downstream circuit (A) is sealed. If the cylinder is perfectly sealed, this leakage means there is no makeup flow, and pressure will slowly decay. For applications requiring the cylinder to hold pressure for extended periods (like a fail-safe brake or clamp), the circuit should include a check valve​ between the reducing valve and the cylinder, or use a pilot-operated reducing valve designed for minimal leakage.

5. Q: The adjustment is very sensitive; a small turn causes a large pressure change. Is this normal?

   A:​ Yes, at the higher end of the pressure range, the adjustment can become more sensitive. This is due to the non-linear force of the compression spring inside the valve. A given turn of the screw compresses the spring further, resulting in a larger force (and thus pressure) increase. This is a characteristic of direct-acting designs. For fine adjustment at high settings, make very small, incremental turns and allow the pressure to stabilize between adjustments.