R983032410 2FRM6B36-2X/3QRV-IN001 Rexroth German made speed control valve

Q1: Is this a simple throttle / needle valve?

No. A simple needle valve lets flow vary with pressure difference. The 2FRM is pressure-compensated​ — the built-in compensator spool keeps the set flow essentially constantdespite load or supply pressure changes (provided ≥~15 bar ΔP across compensator).

Q2: What does "B36 /3QRV" mean?

• B36​ = NG6 sandwich, rotary knurled knob with scale (0–max reference) + locking setscrew — adjustable by hand.

• /3​ = maximum adjustable flow = 3 L/min​ (fine-metering version; also available: /6, /10, /16, /25, /32).

• Q​ = flow controlled in A→B direction.

• R​ = free reverse flow B→A via check valve.

• V​ = NBR seals (standard).

Q3: How do I set the flow?

Loosen the lock setscrew, turn the knurled knob clockwise to increase flow, counterclockwise to decrease. The knob has a relative scale — use a flow meter to correlate to actual L/min. Retighten the lock setscrew after setting.

Q4: How is it mounted?

As a sandwich (stackable) valve​ between a directional control valve and the NG6 subplate, same bolt pattern as ZDR/Z2FS sandwiches (4× M5). Observe the arrow on the valve body — A→B = controlled/metered flow, B→A = free return.

Q5: Does it work both ways?

No — one direction is pressure-compensated metered flow (A→B), the opposite direction (B→A) is free return through the check valve​ (no flow control, minimal pressure drop ~0.5 bar). For bidirectional flow control use two 2FRM valves.

Q6: Minimum pressure requirement?

The pressure compensator typically needs min. ~15 bar differential pressure across the compensator​ to regulate properly. Supply pressure must exceed the highest load pressure + ~15–20 bar + line losses.

Q7: Common faults & causes?

• Flow varies with load pressure:​ compensator spool stuck (contamination) — check oil filtration (ISO 4406 18/16/13 or better); or insufficient ΔP across compensator.

• No flow / very low at max knob:​ valve installed backwards, or compensator/spool jammed.

• Cannot reach set flow / unstable:​ partially clogged orifice (critical at low flows — fine filtration essential), cold-start high viscosity.

• Excessive heat:​ normal for flow controls — P_drop × Q = heat; ensure supply pressure isn't unnecessarily high.

Q8: Fluid & seal compatibility?

NBR seals = mineral oil (HL/HLP) & HFC (water-glycol). For HEES/HETG biodegradable oils or HFD phosphate ester → specify FKM (Viton) seal variant.