I. Model Meaning (Sequentially)

D631: 631 Series Two-stage Mechanical Feedback Servo Valve

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

273: Flow Code → 27 L/min @ Δp=35 bar; Last Digit 3 = Zero Position Ultra-Low Leakage

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

Sentence: Z273C = Non-Explosion-proof + 27 L/min + Built-in Pilot + Ultra-Low Zero Position Leakage

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

Rated Flow: 27 L/min Moog Inc.

Maximum Working Pressure: 315 bar

Frequency Response (−3 dB, 90°): ≈ 65–75 Hz Moog Inc.

Step Response (100%): ≈ 20–25 ms Moog Inc.

Hysteresis: ≤ 0.3%

Resolution: ≤ 0.1%

Zero Position Leakage: ≈ 0.25 L/min (About 45% lower than 272C)

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 D631Z273C and Z272C (Key Points) Table

Project D631Z273C (Low Leak Version) D631Z272C (Standard Version)

Rated Flow Rate 27 L/min 27 L/min

Frequency Response 65–75 Hz 65–75 Hz

Zero-Flow Leakage ≈0.25 L/min ≈0.45 L/min

Power Consumption (Standby) Lower (Less Heat Generation) Standard

Price Slightly Higher (+10~15%) Benchmark

Applicable Conditions Long-term standby, low load, energy-saving priority Regular continuous operation

In one sentence: Z273C is the "energy-saving and low-leakage specialized version" of Z272C, with the same flow rate, half the leakage, and a slightly higher price.

Four. Features and Applications Characteristics

✅ 27 L/min high-flow rate + extremely low leakage: balancing response and energy conservation

✅ Built-in pilot: no need for external X port, the system is simple and easy to install

✅ High dynamic range (65–75 Hz): excellent response at medium flow rate Moog Inc.

✅ Non-explosion-proof Z-type: suitable for ordinary industrial environments, with controllable cost

Typical applications

Long-term standby hydraulic systems: injection molding machines, presses, automated lines (nighttime / standby mode)

Precise low-power closed-loop: material testing machines, vibration tables, precise displacement control Moog Inc.

Energy-saving renovation in non-explosion-proof areas: replace Z272C to reduce energy consumption and heat generation

Metallurgy / Papermaking / Printing (non-explosion-proof section): roll gap, tension, synchronization control Moog Inc.