CUBIC INSTRUMENTS CUBIC-LGA-EX Tunable Diode Laser Absorption Spectroscopy (TDLAS) Gas Analyzer for Hazardous Areas
| Brand | CUBIC INSTRUMENTS |
|---|---|
| Origin | Hubei, China |
| Model | CUBIC-LGA-EX |
| Measurement Principle | Tunable Diode Laser Absorption Spectroscopy (TDLAS) |
| Measured Gases | O₂, CO, CO₂, H₂S, CH₄ |
| Explosion Protection Rating | Ex db IIC T6 Gb / Ex tb IIIC T80°C Db |
| Response Time | <40 s (at 2 L/min) |
| Sample Flow Rate | 0.7–1.2 L/min (max 2 L/min) |
| Accuracy | ±0.5–2% FS depending on gas and range |
| Resolution | 0.01% vol / 0.1 ppm / 1 ppm (gas- and range-dependent) |
| Output Signals | 4–20 mA, RS-232, RS-485 |
| Display | Integrated LCD |
| Power Supply | AC 220 V, 50 Hz |
Overview
The CUBIC-LGA-EX is a certified intrinsically safe, explosion-proof tunable diode laser absorption spectroscopy (TDLAS) gas analyzer engineered for continuous, real-time monitoring of critical process gases—including O₂, CO, CO₂, H₂S, and CH₄—in hazardous industrial environments. Unlike conventional electrochemical or NDIR analyzers, the CUBIC-LGA-EX employs single-line, wavelength-scanned TDLAS to achieve highly selective detection with minimal cross-sensitivity, even in complex gas matrices. Its optical path is sealed and pressure-stabilized, eliminating drift from ambient temperature fluctuations or mechanical vibration. The instrument integrates an in-line sample conditioning module—comprising particulate filtration, moisture removal, and flow regulation—to maintain analytical integrity under high-humidity, high-dust, or oil-laden process streams typical in upstream oil & gas, refining, biogas upgrading, and landfill gas recovery applications.
Key Features
- Explosion-proof certification compliant with IEC 60079-0, IEC 60079-1 (flameproof enclosure “d”), and IEC 60079-31 (powder-filled “t”) standards: Ex db IIC T6 Gb for gas atmospheres and Ex tb IIIC T80°C Db for combustible dust zones.
- TDLAS-based optical detection ensures immunity to electromagnetic interference, zero baseline drift over extended operation, and no consumables—eliminating frequent calibration gas requirements.
- Onboard zero-air pump enables automated air-based zero-point verification without external gas cylinders, supporting unattended long-term deployment.
- Real-time self-diagnostic capability continuously monitors laser output power, photodetector response, signal-to-noise ratio, and flow stability—logging fault codes and triggering configurable alarms via digital outputs.
- Modular pre-conditioning unit includes sintered stainless-steel particulate filter (≤1 µm retention), Peltier-cooled condensate trap (dew point ≤5°C), and precision mass flow controller—designed for sustained operation at up to 95% RH and 10 mg/m³ dust loading.
- Configurable analog (4–20 mA) and serial (RS-232/RS-485 Modbus RTU) outputs support integration into DCS, SCADA, and SIS systems with timestamped data packets compliant with ISA-88 and ISA-95 frameworks.
Sample Compatibility & Compliance
The CUBIC-LGA-EX accepts raw process gas streams requiring only coarse particulate removal prior to inlet. It is validated for use with natural gas, refinery off-gas, syngas, flare gas, and biogas—provided inlet temperature remains within 0–50°C and total hydrocarbon content does not exceed 10% vol (to prevent optical window fouling). All measurement ranges and accuracies are traceable to NIM-certified reference standards (China National Institute of Metrology), with calibration gases prepared in ultra-high-purity nitrogen (≥99.999% N₂, ISO 8573-1 Class 1). The analyzer conforms to EN 14181 (QAL1/QAL2), EN 15267 (performance certification), and supports audit-ready data logging aligned with ISO/IEC 17025 quality management requirements. Optional firmware modules enable compliance with FDA 21 CFR Part 11 for electronic records and signatures in regulated manufacturing environments.
Software & Data Management
The embedded firmware provides local configuration via intuitive LCD menu navigation and remote access through ASCII command protocol over RS-232/485. Data logging occurs at user-selectable intervals (1 s to 1 h) with internal non-volatile memory retaining ≥30 days of second-level measurements. Export is supported via USB flash drive in CSV format, including timestamps, gas concentrations, diagnostic flags, and environmental parameters (inlet pressure, temperature, flow rate). An optional Windows-based PC software suite enables trend visualization, alarm threshold configuration, report generation (PDF/Excel), and integration with OPC UA servers for enterprise-level data federation. Audit trails record all configuration changes, zero calibrations, and maintenance events with operator ID and timestamp—meeting GLP/GMP documentation rigor.
Applications
- Natural gas transmission pipelines: real-time H₂S and O₂ monitoring for corrosion control and specification compliance (ISO 8573-6, ASTM D1946).
- Refinery fluid catalytic cracking (FCC) units: CO and CO₂ analysis in regenerator flue gas for combustion efficiency optimization and emissions reporting (EPA Method 3A, EN 15267-3).
- Liquefied natural gas (LNG) terminals: CH₄ purity verification and O₂ ingress detection in cryogenic storage and loading arms.
- Landfill and anaerobic digestion facilities: simultaneous CH₄/CO₂ ratio tracking for energy recovery optimization and fugitive emission quantification per IPCC Tier 2 protocols.
- Chemical synthesis reactors: in-situ O₂ monitoring for stoichiometric control in oxidation processes where explosive limits must be maintained below 10% LEL.
FAQ
What safety certifications does the CUBIC-LGA-EX hold for hazardous area installation?
It carries dual certification: Ex db IIC T6 Gb for Group IIC gases (e.g., hydrogen, acetylene) and Ex tb IIIC T80°C Db for conductive dusts (e.g., coal, aluminum powder), fully compliant with IEC 60079 series and ATEX 2014/34/EU.
Can the analyzer operate without external zero gas supply?
Yes—the integrated zero-air pump draws ambient air through a desiccant and particulate filter, enabling automatic zero calibration without bottled gas or external compressors.
How is moisture handled in wet process streams?
The built-in Peltier-cooled condenser maintains sample dew point below 5°C; combined with hydrophobic membrane filtration, it prevents liquid carryover and optical path contamination.
Is the system compatible with existing plant DCS architectures?
Yes—it provides native 4–20 mA analog outputs with HART option, plus Modbus RTU over RS-485, enabling direct integration into Emerson DeltaV, Honeywell Experion, and Siemens PCS7 systems without gateway hardware.
What maintenance intervals are recommended for field operation?
Filter elements require replacement every 6 months under typical refinery conditions; laser and detector modules are rated for >50,000 hours MTBF, with no routine optical alignment required due to monolithic optical bench design.
