I. Model-by-Position Explanation (D633-318B)

D633: D633 series direct-acting servo valve (DDV), NG6 (03) mounting surface, Moog Inc.

318:

3: Flow code → 40 L/min (Δp=35 bar)

1: Electronic / Frequency response → Standard frequency response (60–90 Hz), analog input, position closed-loop, Moog Inc.

8: Y port / Seal → With Y port (T port can withstand 350 bar high pressure), NBR seal, -20 to +80℃, Moog Inc.

B: Standard type, without special coating, standard voltage version

One sentence: D633-318B = NG6 + 40 L/min@35 bar + 350 bar (P/A/B/T/Y) + direct actuation without pilot valve + 60–90 Hz standard frequency response + with Y port (T port high pressure) + NBR seal

II. Core Parameters (Δp=35 bar)

Rated flow: 40 L/min (dominant flow in D633 series)

Maximum pressure:

P/A/B/T/Y: 350 bar (full port high pressure) Moog Inc.

Hysteresis: <0.2%

Resolution: <0.1%

Frequency response (±100%): 60–90 Hz (standard mode) Moog Inc.

Step response: ≈12 ms Moog Inc.

Zero position leakage: ≈0.5 L/min (210 bar)

Seal / Temperature: NBR (-20 to +80℃)

Drive: 24VDC, ±10V or 4–20mA Moog Inc.

Filter: ISO 4406 15/12

Features: No pilot hole, extremely anti-pollution, independent of dynamic and pressure, power-off spring centering, full port 350 bar high pressure, unique model for D633 series 40 L/min standard dynamic + high-pressure return oil

III. Comparison of D633-318B with 317B/315B (Key Differences) Table

Project D633-317B D633-315B D633-318B

Flow rate 40 L/min 75 L/min 40 L/min

Frequency response 60–90 Hz 120–150 Hz 60–90 Hz

Y port No (T≤50bar) No (T≤50bar) Yes (T=350bar)

Sealing NBR 80℃ NBR 80℃ NBR 80℃

Return oil pressure Low pressure return oil Low pressure return oil High pressure return oil (350bar)

Sentence: 318B = 317B's high-pressure return oil version, with the same flow rate / frequency response / sealing, the T port upgraded to 350bar high pressure, suitable for high-pressure return oil system

Four. Application scenarios

NG6 small installation surface, 40L/min medium flow rate + 350bar full port high pressure + 60–90Hz standard frequency response + standard temperature (≤80℃)

High-pressure return oil (350bar) at the T port, requires Y port leakage or high-pressure return oil circuit from Moog Inc.

High-pressure return oil system: high-pressure accumulator circuit, high-pressure overflow return oil, metallurgical high-pressure roll gap, high-pressure testing machine

Installation space limited, 40L/min flow rate is sufficient, regular dynamic response, high-pressure return oil high-pressure system