Model Code Definition

D664 = NG25 ISO4401 installation size, ServoJet jet-pipe pilot, onboard integrated amplifier + full-range LVDT spool closed-loop feedback, D660 high-flow subseries

4308 = Factory pre-calibrated zero-overlap four-way spring-centered metering spool with fixed original flow gain

K = Customized amplifier circuit calibration version, optimized gain & null drift compensation for continuous heavy-load rolling mill service, no standard factory default amplifier parameter

Technical Specifications

Hydraulic Parameters

Rated Flow:330 L/min @35bar single-side differential pressure; peak instantaneous flow 1290 L/min @70bar supply differential pressure

Max Working Pressure:P/A/B main ports rated 350bar; internal T drain ≤210bar; external Y drain full 350bar allowable working pressure

100% Full Stroke Step Response:≤35ms under nominal 210bar supply hydraulic pressure

Control Precision:Hysteresis＜0.32%FS, Resolution＜0.09%FS, total thermal drift(-20~+80℃)＜2.7%FS (optimized via K-version circuit)

Null Leakage:0.38~2.05 L/min based on factory spool machining tolerance

Working Medium:Anti-wear mineral hydraulic oil, fluid cleanliness NAS6~7 / ISO4406 17/14/11, operating fluid temperature -20℃~+80℃

Net Weight:5.50kg

Electrical Parameters

Input Power Supply:24VDC wide input(18~32VDC), quiescent standby current ≤920mA

Default Control Signal:Factory standard ±10VDC differential analog input; ±10mA /4~20mA current signal optional per modification requestMoog Inc.

Connector:11-pin circular aviation receptacle, IP65 protection after complete cable assembly

EMC Standard:Compliant with EN55011 industrial electromagnetic compatibility specification

Port & Connection Configuration

Hydraulic Interface:ISO4401 NG25 standard hole layout including P supply port, A/B actuator control ports, separated built-in T internal drain and dedicated Y external drain; pre-installed original NBR mounting gasket, standard X pilot port blocked with factory plug for non-external pilot oil setup

Electrical Interface:11-pin circular socket integrates 24V power supply, ±10V command signal and full-range LVDT feedback wiring; double-shielded control cable required with single-point cabinet grounding, no fieldbus communication functionMoog Inc..

Core Functions

1.Patented ServoJet jet-pipe pilot delivers superior anti-pollution performance versus conventional nozzle-flapper pilot, stable long-running under rolling mill medium-polluted hydraulic oil environment.

2.K-version customized amplifier optimizes temperature drift suppression, four-way zero-lap spool realizes high-precision closed-loop position/speed/force control for heavy-duty continuous rolling equipment; onboard LVDT dynamically compensates spool thermal deformation drift.

3.Spring-centered fail-safe neutral structure: main spool returns to middle position automatically upon power loss to lock hydraulic cylinder and protect rolling mill roll stand from runaway damage.

4.Factory pre-set optimized gain matching mill cyclic fluctuating load; ±10VDC analog input features strong anti-interference for long-distance field wiring on metallurgical production line.

Typical Application

Steel cold/hot rolling mill roller gap closed-loop servo control, strip thickness automatic adjustment system of metallurgical continuous rolling line, heavy slab hydraulic pressing equipment, large-scale metal forging press master cylinder flow regulation.

Installation & Maintenance Instructions

1.Mount 3μm high-precision inline high-pressure filter on upstream P supply pipeline; replace filter element after first 15 working days of mill commissioning startup.

2.Separate power cable and shielded control wire in independent wiring channels to avoid frequency converter harmonic interference; fix valve with factory specified bolt torque and standard flat washers.

3.Flow gain and null offset of K-customized version are pre-calibrated at MOOG factory; only minor on-site potentiometer fine-tuning permitted; full disassembly of ServoJet pilot assembly and main spool is strictly forbidden.

4.Seal unused spare T/Y drain ports with original factory blank plugs during spare part storage; store valve in dry dustproof warehouse to avoid NBR rubber seal ageing and oil leakage.