I. Model-by-digit explanation (D633-333B)

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

333:

3: Flow code → 75 L/min (Δp=35 bar, peak)

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

3: Y port / Seal → No Y port (T port low pressure ≤ 50 bar), NBR seal, -20 to +80℃

B: Standard type, no special coating, standard voltage version

In one sentence: D633-333B = NG6 + 75 L/min@35 bar high flow + 350 bar (P/A/B) + direct actuation without pilot + 60–90Hz standard frequency response + no Y port (T port low pressure) + NBR seal

II. Core parameters (Δp=35 bar)

Rated flow: 75 L/min (peak, maximum flow of D633)

Maximum pressure:

P/A/B: 350 bar

T port: ≤ 50 bar (no Y port)

Hysteresis: <0.2%

Resolution: <0.1%

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

Step response: ≈12 ms

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

Seal / Temperature: NBR (-20 to +80℃)

Drive: 24VDC, ±10V or 4–20mA

Filter: ISO 4406 15/12

Features: No pilot hole, extremely anti-pollution, independent of dynamic and pressure, spring alignment in case of power failure, high flow + standard dynamics + low-pressure return oil, maximum flow model of NG6 mounting surface

III. Comparison of D633-333B with 315B/320B (Key differences) Table

Project D633-315B D633-320B D633-333B

Flow rate 75 L/min 25 L/min 75 L/min

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

Y port No (T≤50bar) No (T≤50bar) No (T≤50bar)

Positioning High-flow standard dynamic High-flow high-frequency dynamic High-flow standard dynamic (NG6 top-end flow)

In one sentence: 333B = 315B's standard version / 320B's high-flow version. NG6 installation surface 75L/min high-flow + standard frequency response + low-pressure return oil is the only model.

Four. Application scenarios

NG6 small installation surface, 75L/min high-flow (D633 maximum) + 350bar (P/A/B) + 60–90Hz standard frequency response + standard temperature (≤80℃)

T port low-pressure return oil (≤50bar), no need for Y port leakage

High-flow precise control: General hydraulic station, press machine, injection molding machine, heavy equipment position/velocity control, high-flow low-frequency high-precision system

Installation space limited, need 75L/min high-flow, standard frequency response, low-pressure return oil, high-pressure system