I. Model Meaning (Digit by Digit)

D631: 631 Series Two-stage Mechanical Feedback Servo Valve

Z: Standard Non-Explosion-proof Type (General Industrial Environment)

407: Flow Code → 40 L/min @ Δp=35 bar; The last digit 7 = Special Customization (Low Leakage + Zero Position / Gain Optimization)

C: Built-in Pilot Supply Oil, NBR Seal, Low Leakage Valve Core

In one sentence: Z407C = Non-Explosion-proof + 40 L/min High Flow + Built-in Pilot + Low Leakage + Special Zero Position Customization

II. Core Parameters (Δp=35 bar / Each Side)

Rated Flow: 40 L/min (Mainstream High Flow Gear of 631 Series)

Maximum Working Pressure: 315 bar

Frequency Response (−3 dB, 90°): ≈ 50–60 Hz (Typical Value for High Flow)

Step Response (100%): ≈ 28–32 ms

Hysteresis: ≤ 0.3%

Resolution: ≤ 0.1%

Zero Position Leakage: ≈ 0.35 L/min (Low Leakage Customization, Better than Standard 400C)

Pilot Supply Oil: Built-in (Oil is taken from Port P)

Explosion-proof Grade: None (Z = Non-Explosion-proof)

Temperature Range: −20 ℃ ~ +80 ℃

Filter Requirements: NAS 6–7 / ISO 4406 <14/11

III. Comparison of D631Z407C with 341C/359C/400C (High Flow Customization Gear) Table

Project D631Z407C (40 L/min low leakage custom) D631Z359C (35 L/min low leakage custom) D631Z341C (34 L/min standard) D631Z400C (40 L/min standard)

Rated Flow Rate 40 L/min 35 L/min 34 L/min 40 L/min

Frequency Response 50–60 Hz 55–65 Hz 55–65 Hz 50–60 Hz

Zero-Position Leakage ≈0.35 L/min (low leakage custom) ≈0.30 L/min (low leakage custom) ≈0.55 L/min (standard) ≈0.60 L/min (standard)

Custom Features ✅ Low leakage + zero position / gain optimization ✅ Low leakage + zero position fine-tuning ❌ Standard configuration ❌ Standard configuration

Price Baseline + 25% (high flow custom premium) Baseline + 20% Baseline Baseline + 15%

In one sentence: D631Z407C is the "low leakage + custom version" of 40 L/min: maximum flow rate, leakage far lower than standard D631Z400C, with zero-position customization, and the highest price, suitable for triple requirements of high flow rate, energy saving, and high precision.

Four. Features and Applications Characteristics

✅ 40 L/min high flow rate + low leakage: The mainstream high-flow rate setting of the 631 series, with leakage approximately 42% lower than the standard 400C

✅ Built-in pilot: No need for an external X port, making the system simple and facilitating installation and maintenance

✅ Customization (7): Zero gain/offset fine-tuning, low leakage optimization, suitable for high-precision closed-loop

✅ Non-explosion-proof Z-type: Suitable for ordinary industrial environments, with a cost lower than the explosion-proof K-type

Typical applications

High flow rate + low energy consumption closed loop: Large presses, injection molding machines for large mold/shot molding, die-casting machines

High-precision large actuators: 40 L/min level cylinders/motors, requiring low leakage + zero position stability

Metallurgy / papermaking / printing (non-explosion-proof section): Super large roller diameter tension control, synchronous drive, thick plate press-down system

Testing equipment: Ultra-large material testing machines, high-flow rate + high-precision dual requirements high-frequency large-load vibration tables