Model Code Decoding

• D635: Series, NG06 (Cetop 3) pressure control valve

• 671:

  • 6: Rated flow 20 L/min (Δp=35 bar/land)

  • 7: Rated pressure 210 bar (max 250 bar)

  • 1: 3‑way spool, linear, standard overlap

• E: Revision E, FPM (Viton) seals, enhanced EMC, 24 VDC supply (current production)

Technical Specifications

• Part Number: D635-671E

• Valve Size: NG06 (Cetop 3 / ISO 4401‑03)

• Control Function: 3‑way pressure control, spring‑centered (fail‑safe: A→T, P→B)

• Rated Flow (Δp=35 bar/land): 20 L/min (±10% tolerance)Moog Inc.

• Max Flow: 25 L/min

• Operating Pressure:

  • P/A/B ports: 210 bar (3,000 psi)

  • T port (without Y): 50 barMoog Inc.

  • Y port: Optional (210 bar T)

• Response Time (0→100% step): ≤15 ms

• Hysteresis: <0.15%Moog Inc.

• Null Shift (ΔT=55 K): <1.0%

• Linearity: <0.5%

• Electrical:

  • Supply: 24 VDC (19–32 VDC), 1.0 A maxMoog Inc.

  • Signal: 0–10 V, 0–10 mA, or 4–20 mA (command); 4–20 mA (pressure feedback)Moog Inc.

  • Connector: 6+PE (DIN 43563), IP65 (mated)Moog Inc.

• Fluid: Mineral oil (DIN 51524), viscosity 5–400 mm²/s

• Temperature:

  • Ambient: −20°C to +60°C

  • Fluid: −20°C to +80°C

• Mass: ~2.5 kgMoog Inc.

• Seals: FPM (Viton, high‑temp resistant)

Interface & Communication Configuration

• Electrical Interface: Analog command (0–10 V / 0–10 mA / 4–20 mA) + 24 VDC power; 4–20 mA pressure feedbackMoog Inc.

• Feedback: Integrated pressure sensor (closed‑loop); no external transducer needed

• Mounting: 4‑bolt NG06 (Cetop 3, M5 screws, 8–10 Nm torque)

• Porting: P, A, B, T (Y port optional)

Core Functions

1. Integrated Pressure Control: Onboard sensor + electronics, no external controller required

2. 20 L/min Medium Flow: Balanced flow for general‑purpose pressure control

3. 210 Bar Standard Pressure: For medium‑duty hydraulic systems

4. Direct‑Drive Linear Motor: No pilot flow, fast response, low hysteresis

5. Fail‑Safe Spring Center: A→T, P→B on power loss

6. Revision E: FPM seals, wide temp range, enhanced EMC protection

Application Scenarios

• Industrial Hydraulics: General‑purpose pressure control, medium‑pressure systems

• Test Systems: Pressure cycling benches, component durability testers

• Machine Tools: Standard clamping, spindle preload control

• Hydraulic Presses: Closed‑loop pressure regulation for light forming

Compatibility & Key Differences

• Series Compatibility: Interchangeable with D635 2.5/5/10/40 L/min models (same NG06 mounting)

• D635-671E vs D635-671D:

  • 671E: 20 L/min, 210 bar, FPM seals, −20°C to +60°C, enhanced EMC (current)

  • 671D: 20 L/min, 210 bar, NBR seals, −20°C to +50°C, basic EMC (legacy)

• Replacement: Direct drop‑in upgrade from D635-671D (better performance & reliability)