I. Model Breakdown (D633-312B)

D633: Direct-acting servo valve (DDV) of the D633 series, NG6 (03) mounting surface

312:

3: Flow code → 75 L/min (Δp=35 bar)

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

2: Y port / Seal → With Y port (exhaust), NBR seal, -20 to +80°C; T port can withstand 350 bar

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

In one sentence: D633-312B = NG6 + 75 L/min@35bar + 350bar high pressure + direct actuation without pilot valve + 60–90Hz standard frequency response + with Y port (high-pressure return oil) + NBR seal

II. Core Parameters (Δp=35 bar)

Rated flow: 75 L/min (maximum of the D633 series)

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

Hysteresis: <0.2%

Resolution: <0.1%

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

Step response: ≈12 ms

Zero leakage: ≈0.8 L/min (210 bar)

Seal / Temperature: NBR (-20 to +80°C)

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, spring alignment in case of power failure, with Y port high-pressure return oil (T/Y=350bar), absolute flow upper limit of D633 small mounting surface

III. Comparison of D633-312B with 302B/303B/304B/308B Table

Project 303B (5L) 302B (10L) 304B (20L) 308B (40L) 312B (75L)

Flow rate 5 L/min 10 L/min 20 L/min 40 L/min 75 L/min

Y port No Y (T≤50bar) No Y (T≤50bar) No Y (T≤50bar) No Y (T≤50bar) With Y (T/Y=350bar)

Zero leakage ≈0.05 L/min ≈0.1 L/min ≈0.2 L/min ≈0.4 L/min ≈0.8 L/min

Positioning Ultra-small flow micro-control Small flow basic type Middle-small flow main force NG6 maximum internal leakage NG6 maximum flow + high-pressure return oil

Sentence: 312B is the "almost double flow rate + Y port high-pressure return oil" version of 308B, the ceiling of the D633 series flow rate

Four, applicable scenarios

NG6 small installation surface, requiring 75 L/min large flow rate + 350bar full port high pressure

T port return oil pressure is high (≤350bar), Y port leakage is necessary

Standard dynamic (60–90Hz), normal temperature (≤80℃) environment

Medium-large power high-pressure precision control: large presses, injection molding machines large cylinders, die-casting machines, heavy bending machines, metallurgical rolling machines, fatigue test machines

Systems with extremely limited installation space but requiring the extreme flow rate + high-pressure return oil of the D633 series