I. Explanation of Model Numbers

D631: 631 Series Two-stage Mechanical Feedback Servo Valve

Z: Non-explosion-proof, standard industrial environment

827: Flow code 80 L/min (Δp = 35 bar); Last digit 7 = Ultra-low leakage + Low temperature drift + High stability valve core (High-end precision grade)

C: Internal pilot + FPM (fluorine rubber) seal (High-temperature type)

In one sentence: Z827C = 80L/min high flow + Internal pilot without external connection + FPM high-temperature seal + Ultra-low leakage and high stability precision type

II. Core Parameters (Δp = 35 bar)

Rated Flow: 80 L/min

Maximum Pressure: 315 bar

Frequency Response (−3dB/90°): 40–50 Hz (Priority for stability)

Step Response: 35–40 ms

Hysteresis: ≤0.2% (Better than ordinary models)

Resolution: ≤0.05% (Ultra-high precision)

Zero Position Leakage: ≈0.15 L/min (7 type = Ultra-low leakage, lowest among 80L)

Zero Position Temperature Drift: ≤0.5%/55℃ (Low temperature drift, precise control)

Pilot Method: Internal pilot (No X port required)

Sealing / Temperature: FPM (−20 to +120℃)

Filter: NAS 6–7 / ISO 4406 14/11

III. Ultimate Comparison of the 80L Five Brothers (827C/803C/820C/824C) Table

Parameters: D631Z827C, D631Z803C, D631Z820C, D631Z824C

Flow rate: 80 L/min, 80 L/min, 80 L/min, 80 L/min

Preamplifier: Internal, Internal, Internal, Internal

Leakage type: 7 = Ultra-low leakage (≈0.15), 3 = Low leakage (≈0.30), 0 = Standard leakage (≈0.50), 4 = High leakage (≈0.80)

Frequency response: 40–50 Hz (stable), 40–50 Hz, 40–50 Hz, 50–60 Hz (fast)

Step response: 35–40 ms, 35–40 ms, 35–40 ms, 25–30 ms (fastest)

Hysteresis / Resolution: ≤0.2%/≤0.05% (precise), ≤0.3%/≤0.1%, ≤0.3%/≤0.1%, ≤0.3%/≤0.1%

Temperature drift: ≤0.5%/55℃ (extremely low), normal, normal, normal

Power consumption / Heat generation: Minimum (extreme energy saving), low, medium, high

Price: Highest (precise model), medium-high, economy, medium-high

Core advantages: Ultra-low leakage + Low temperature drift + High precision, Low leakage energy saving, Balanced versatility, High dynamic response

In one sentence: 827C is the "precise king" among 80L models - with the lowest leakage, the smallest temperature drift, the highest precision, and the most expensive price.

Four, applicable scenarios (Z827C)

High-precision closed-loop control: Precision presses, synchronous lifting, positioning platforms

Long-term standby / 24-hour continuous operation: Energy-saving priority, low energy consumption requirements

High temperature environment with large temperature fluctuations: Oil temperature fluctuation is large, zero drift needs to be suppressed

Metallurgical precision rolling, material testing equipment, aviation ground simulation