Model Code Decoding

• D634: Series, ISO 4401‑05 (NG10) sizeMoog Inc.

• Z: High‑flow 4‑way (enhanced flow paths)

• 35: Rated flow 180 L/min (Δp=35 bar/land)

• 1: Spool/bushing type (4‑way, linear, zero overlap)

• C: Special revision C (industrial standard, FPM seals, enhanced EMC)

Technical Specifications

• Part Number: D634Z351C

• Valve Size: ISO 4401‑05 (Size 05 / NG10)Moog Inc.

• Control Function: 4‑way flow control, spring‑centeredMoog Inc.

• Rated Flow (Δp=35 bar/land): 180 L/min (±10% tolerance)Moog Inc.

• Max Flow: 200 L/min

• Operating Pressure:

  • P/A/B ports: 350 bar (5,000 psi)Moog Inc.

  • T port (without Y): 50 bar; (with Y): 210 barMoog Inc.

• Response Time (0→100% step): ≤20 msMoog Inc.

• Hysteresis: <0.2%Moog Inc.

• Null Shift (ΔT=55 K): <1.5%Moog Inc.

• Electrical:

  • Supply: 24 VDC (18–32 VDC), 3.0 A maxMoog Inc.

  • Signal: ±10 V, ±10 mA, or 4–20 mAMoog Inc.

  • Connector: 6+PE (EN 175201), IP65 (mated)Moog Inc.

• Fluid: Mineral oil (DIN 51524), viscosity 15–100 mm²/s

• Temperature:

  • Ambient: −20°C to +60°C

  • Fluid: −20°C to +85°C

• Mass: ~8.2 kg

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

Interface & Communication Configuration

• Electrical Interface: Analog command (±10 V / ±10 mA / 4–20 mA) + 24 VDC powerMoog Inc.

• Feedback: Integrated spool position sensor (closed‑loop); optional 2–10 V actual‑value outputMoog Inc.

• Mounting: 4‑bolt ISO 4401‑05 (M6 screws, 11–13 Nm torque)Moog Inc.

• Porting: P, A, B, T; optional drain Y (for T > 50 bar)Moog Inc.

Core Functions

1. Ultra‑High‑Flow 4‑way: 180 L/min rated flow for large‑bore actuators

2. Direct‑Drive Linear Motor: No pilot flow, pressure‑independent dynamicsMoog Inc.

3. Integrated Closed‑Loop: Onboard spool position feedback for high accuracyMoog Inc.

4. Zero‑Overlap Spool: Improved linearity, lower null leakage, precise control

5. High Dynamic Response: ≤20 ms step response for fast positioning/force controlMoog Inc.

6. EMC Enhanced: Revision C improves noise immunity for industrial environmentsMoog Inc.

7. FPM Seals: High‑temperature compatibility, longer service life

8. Fail‑Safe Spring Center: Spool returns to mid‑position on power lossMoog Inc.

Application Scenarios

• Heavy Industrial Machinery: Large injection molding, die‑casting, metal forming presses

• Test & Simulation: High‑force vibration test benches, large flight simulators

• Hydraulic Actuation: Precision control of large‑bore hydraulic cylinders

• Harsh Industrial Systems: High‑temperature, high‑noise factory environments

Compatibility Note

• Series Compatibility: Interchangeable with D634Z 100/160/180 L/min models and standard D634 4‑way valvesMoog Inc.

• Key Difference (351C vs 314C):

  • 314C: 160 L/min, standard overlap

  • 351C: 180 L/min, zero overlap, higher max flow

• Replacement: Drop‑in upgrade for lower‑flow D634K series or pilot‑operated high‑flow servo valvesMoog Inc.