ATAGO CM-ISα-EG Intrinsically Safe In-Line Ethylene Glycol Concentration Meter

Overview

The ATAGO CM-ISα-EG is an intrinsically safe, in-line process refractometer engineered for continuous, real-time measurement of ethylene glycol (EG) concentration in liquid-phase heat transfer fluids, antifreeze solutions, deicing fluids, and brine systems. It operates on the principle of critical-angle refractometry: a collimated LED light beam passes through a sapphire prism in direct contact with the process stream; the resulting refraction angle is precisely detected by a high-resolution linear CCD sensor, enabling calculation of the solution’s refractive index (RI). Using a rigorously validated, temperature-compensated calibration model specific to ethylene glycol–water binary mixtures, the instrument derives EG mass concentration (% w/w) and corresponding freeze point (°C or °F) without chemical reagents or sample extraction. Its robust stainless-steel wetted parts (316L SS body, sapphire prism) and fully sealed optical path ensure long-term stability in aggressive industrial environments—including steam tracing, high-pressure coolant loops, and cryogenic glycol recovery lines.

Key Features

• Intrinsically safe design certified to IECEx ia IIC T4 Ga and ATEX II 1G Ex ia IIC T4 Ga (Zone 0/1), as well as UL/cUL Class I, Division 1, Groups A, B, C, D — suitable for installation in hazardous locations without explosion-proof enclosures.
• High-precision optical architecture featuring a thermally stabilized sapphire measuring prism and temperature-controlled LED light source, minimizing drift under thermal cycling conditions typical in HVAC chillers or engine cooling circuits.
• Integrated Pt100 RTD sensor with dual-point verification capability ensures accurate real-time temperature compensation across the full operating range (−15 to 160 °C).
• Factory-calibrated for ethylene glycol–water systems using NIST-traceable reference standards; supports user-defined calibration verification via certified EG standard solutions (0%, 20%, 40%, 50% w/w).
• IP67-rated electronics housing with M20 cable gland entry; optional hygienic tri-clamp (DIN 11851) or ANSI B16.5 flange mounting kits available for sanitary or high-pressure applications.

Sample Compatibility & Compliance

The CM-ISα-EG is optimized exclusively for aqueous ethylene glycol solutions, including inhibited and non-inhibited formulations used in automotive antifreeze, aircraft deicing fluids (Type I & IV), industrial heat transfer media, and refrigeration brines. It is not intended for use with propylene glycol, methanol, or multi-component coolants containing surfactants, corrosion inhibitors, or nanoparticles that may coat the prism surface. The instrument complies with ISO 21501-4 for optical particle-free measurement integrity and meets the mechanical and electrical safety requirements of IEC 60079-0, IEC 60079-11, and EN 61326-1 (EMC for industrial environments). Data traceability supports GLP and GMP workflows when integrated with compliant SCADA or DCS systems.

Software & Data Management

Standard 4–20 mA analog output provides linear transmission of primary process variables (EG %, freeze point, or RI) to PLCs or DCS controllers. Optional digital communication includes Modbus RTU (RS-485) and HART 7 protocols, enabling bidirectional configuration, diagnostics, and live parameter streaming. ATAGO’s optional RefractoLink™ PC Software (v3.2+) supports automated data logging, alarm threshold setup (e.g., freeze point deviation >±2 °C), trend visualization, and CSV export compliant with FDA 21 CFR Part 11 requirements—including electronic signatures, audit trails, and user access control levels (Operator, Technician, Administrator). Firmware updates are performed via USB or Modbus, with version rollback capability for validation continuity.

Applications

• Real-time monitoring of EG concentration in centralized HVAC chiller plants to prevent freezing during winter operation and optimize heat exchange efficiency.
• Automated quality control in antifreeze blending facilities, ensuring batch consistency against ASTM D1177 and SAE J1034 specifications.
• Critical freeze-point verification in aviation ground support equipment (GSE) for Type I deicing fluid preparation per SAE ARP4737 and ISO 11077.
• Process optimization in geothermal heat pump loop fill stations, where precise EG concentration directly impacts system longevity and thermal conductivity.
• Preventive maintenance in industrial compressor cooling circuits, detecting glycol degradation or dilution before catastrophic freeze events occur.

FAQ

What certifications does the CM-ISα-EG hold for hazardous area installation?
It carries IECEx and ATEX certification for Zone 0/1 (ia IIC T4 Ga) and UL/cUL listing for Class I, Division 1, Groups A–D — permitting direct installation in gas-group IIC environments without additional barrier systems.

Can the instrument measure propylene glycol or other glycols?
No. The CM-ISα-EG uses a fixed, factory-loaded calibration algorithm optimized solely for ethylene glycol–water mixtures. Propylene glycol requires a separate instrument model (e.g., CM-ISα-PG) due to distinct refractive index–concentration behavior.

Is prism cleaning required during operation?
Under normal operation with clean, filtered glycol streams, no manual cleaning is needed. For applications prone to fouling (e.g., reclaimed coolant with particulates), optional ultrasonic prism cleaning modules or automated water-rinse cycles can be integrated via auxiliary I/O.

How is temperature compensation applied?
An embedded Pt100 RTD measures fluid temperature at the prism interface in real time. The microprocessor applies a second-order polynomial correction derived from empirical EG–water RI vs. temperature data across 5–100 °C, ensuring accuracy even during transient thermal events.

Does the device support regulatory compliance for pharmaceutical or food-grade processes?
While the wetted materials (316L SS, sapphire) meet 3-A Sanitary Standards #74-01 and FDA 21 CFR 177.1520 for indirect food contact, the CM-ISα-EG itself is not 3-A certified. For pharma applications requiring 21 CFR Part 11 compliance, full validation documentation (IQ/OQ/PQ templates) and firmware audit logs are provided upon request.