I. Model Breakdown Explanation (D633-328B)

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

328:

3: Flow code → 25 L/min (Δp = 35 bar)

2: Electronic / Frequency Response → High frequency response (120–150 Hz), analog input, position closed-loop

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

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

In one sentence: D633-328B = NG6 + 25 L/min@35 bar + 350 bar (P/A/B/T/Y) + direct actuation without pilot valve + 120–150 Hz high frequency response + with Y port (T port high pressure) + NBR seal

II. Core Parameters (Δp = 35 bar)

Rated Flow: 25 L/min (low flow high frequency model)

Maximum Pressure:

P/A/B/T/Y: 350 bar (full port high pressure, including return oil T port)

Hysteresis: <0.2%

Resolution: <0.1%

Frequency Response (±100%): 120–150 Hz (high frequency gear)

Step Response: ≈8 ms

Zero Position Leakage: ≈0.3 L/min (210 bar)

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

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 after power loss, full port 350 bar high pressure, low flow high frequency + high pressure return oil, unique model

III. Comparison of D633-328B with 320B/318B (Key Differences) Table

Project D633-320B D633-318B D633-328B

Flow rate 25 L/min 40 L/min 25 L/min

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

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

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

Positioning Low flow high frequency low pressure return oil Medium flow standard high pressure return oil Low flow high frequency high pressure return oil (top configuration)

Sentence: 328B = 320B's high pressure return oil version / 318B's low flow high frequency version, full port 350bar + high frequency response, D633's low flow series top model

Four, Application scenarios

NG6 small installation surface, 25L/min low flow + 350bar full port high pressure + 120–150Hz high frequency response + standard temperature (≤80℃)

T port high pressure return oil (350bar), requires Y port leakage or high pressure return oil circuit

High frequency + high pressure precision control: high frequency fatigue test machine, high pressure vibration table, precise position control, high pressure accumulator high frequency circuit

Installation space limited, 25L/min is sufficient, need high frequency response + high pressure return oil for high-end systems