NGO3-WATER Online Infrared Oil & Moisture Film Thickness Gauge by Infralytic

Overview

The NGO3-WATER is a high-speed, non-contact online thickness gauge engineered by Infralytic (Germany) for real-time quantification of oil-based passivation films and residual moisture content on continuously moving metal strips—primarily galvanized steel coils in hot-dip galvanizing and post-treatment lines. Unlike contact-based or eddy-current systems, the NGO3-WATER employs near-infrared (NIR) absorption spectroscopy at three precisely selected wavelengths within the 1.5–2.1 µm spectral range. This enables direct, calibration-stable correlation between absorbance intensity and areal mass loading (g/m²), independent of surface topography, electrostatic charge distribution, or minor strip flutter. The instrument operates on Beer–Lambert law fundamentals: infrared photons interact with C–H and O–H vibrational modes in organic oils and water molecules, generating characteristic absorption peaks whose integrated area scales linearly with film thickness under controlled optical path conditions. Its fixed 200 mm working distance and ±20 mm height tolerance accommodate standard roller levelling and tension control deviations without recalibration.

Key Features

• Triple-wavelength NIR detection with P-polarized beam geometry to suppress specular reflection artifacts from glossy, uneven galvanized surfaces
• 50 ms minimum measurement cycle time—synchronized with line speeds up to 1,200 m/min for full-strip coverage at ≤120 Hz sampling rate
• No sample preparation required: fully non-contact operation eliminates risk of coating disturbance, sensor wear, or contamination
• Robust industrial housing (IP65-rated) rated for ambient temperatures from 0 °C to +55 °C, suitable for installation in zinc pot exit zones and cooling sections
• Integrated thermal drift compensation using reference channel monitoring and internal blackbody stabilization
• Modular optical head design allows retrofitting onto existing process frames without structural modification

Sample Compatibility & Compliance

The NGO3-WATER is validated for continuous measurement on hot-dip galvanized (HDG), electrogalvanized (EG), and alloy-coated steel strips, as well as stainless steel, aluminum, and ceramic substrates used in functional coating applications. It meets mechanical and electromagnetic compatibility requirements per EN 61326-1 (industrial environments) and conforms to CE marking directives. While not a certified metrology standard itself, its measurement traceability aligns with ISO 2178 (non-magnetic coatings on magnetic substrates) and ASTM E2822 (quantitative NIR analysis of thin organic layers). Data integrity supports GLP/GMP-aligned production records when paired with compliant SCADA integration and audit-trail-enabled software (see Software & Data Management section).

Software & Data Management

The system interfaces via Ethernet/IP or PROFIBUS DP to plant-level DCS/SCADA platforms. Infralytic’s proprietary NGO Control Suite provides real-time thickness trend visualization, statistical process control (SPC) charting (X̄–R, Cpk), and automated alarm thresholds configurable per coil batch or grade. All raw spectral data, timestamped measurements, and environmental metadata (ambient temperature, strip speed, tension feedback) are stored in SQLite or OPC UA-compliant databases. Optional FDA 21 CFR Part 11 compliance package includes electronic signatures, role-based access control, and immutable audit trails for pharmaceutical-grade coating validation workflows.

Applications

• Real-time monitoring of chromate-free passivation oil dosage in post-galvanizing treatment lines
• Verification of anti-fingerprint coating uniformity on pre-painted or bare Zn/Al-Zn alloy coils
• In-line moisture content verification after rinse stages to prevent white rust formation during storage
• Quality gatekeeping prior to slitting, packaging, or cold rolling—reducing off-spec coil rejection rates
• Process optimization support for roll coater setup, pump calibration, and dryer temperature profiling

FAQ

Does the NGO3-WATER require periodic recalibration with physical standards?
No—its triple-wavelength differential absorption algorithm and built-in reference channel eliminate drift-related recalibration needs. Field verification using NIST-traceable polymer film standards is recommended annually or after major optical maintenance.
Can it distinguish between oil and water signals on the same strip?
Yes—the instrument uses chemometric deconvolution of overlapping C–H and O–H absorption bands; separate g/m² outputs for oil film mass and residual moisture are reported simultaneously.
Is it compatible with high-vibration galvanizing line environments?
Yes—optical head mounting includes passive damping mounts, and spectral acquisition is synchronized to encoder-triggered strip position to reject motion-induced noise.
What strip width ranges does it support?
The NGO3-WATER measures across any width; field-of-view is defined by user-configurable scan line length (standard: 30–120 mm), with optional multi-head arrays for >1,800 mm wide coils.
How is safety ensured during operation near hot strip surfaces?
The NIR source operates below Class 1 laser safety limits (IEC 60825-1); no cooling water or purge gas is required, and the optical head maintains safe standoff distance even during thermal expansion events.