Product Overview
The MDM300 I.S. is an intrinsically safe portable dew‑point moisture meter designed for rapid spot-check moisture measurements in gases such as compressed air, natural gas, and biogas, suitable for hazardous areas.
- Measurement Range: −70 to +20 °C dew point (spot checks), −100 to −70 °C (online)
- Accuracy: ±1 °C (−60 to +20 °C), ±2 °C (−100 to −60 °C)
- Resolution: 0.1 °C dew point
- Response Time: T95 ≤30 minutes to −60 °C
- Output Units: °C, °F, K dew point & gas temperature; %RH; ppmV; g/m³; lb/MMSCF
- Calibration: Traceable 13‑point certificate
- Power: Internal rechargeable NiMH battery (~24 h)
- Operating Temp.: −20 to +50 °C
- Operating Pressure: Up to 35 MPa (350 barg)
- Ingress Protection: IP66 / NEMA 4
- Housing Material: Steel fiber‑loaded polyamide 6
- Certifications: ATEX, IECEx, UKCA, cQPSus, TR CU Ex
- Weight: ~1.5 kg
Description
Measurement Technology
The MDM300 I.S. uses the Michell Ceramic Metal‑Oxide Moisture Sensor, the same advanced sensor technology as the Easidew PRO I.S. This proprietary sensor features a metallised ceramic structure on a semiconductor-grade ceramic base. The sensor functions as a moisture-sensitive capacitor: the impedance of the sensor changes in direct response to the partial pressure of water vapor in the gas, which has a direct correlation with dew-point temperature. The transmitter electronics convert these impedance changes into precise dew-point readings.
This technology provides:
- High robustness and long-term stability compared to traditional aluminium oxide sensors
- Capability to measure aggressive gases, including sour gas containing H₂S, at high pressures without sensor failure
- No zero-shift or memory effects, ensuring consistent accuracy over long-term operation
- Calibration traceable to NPL (UK) and NIST (USA) for reliable measurement integrity
Strengths of Michell Ceramic Sensor:
- World’s most advanced metal-oxide capacitive/impedance sensing principle, derived from aluminium-oxide sensors of the 1950s
- Metallised ceramic structure with hygroscopic dielectric layer
- Impedance varies with moisture partial pressure, calibrated for accurate dew-point measurement across full range
- Highly robust and inert; can measure aggressive gases including sour natural gas with up to 30% H₂S at pressures up to 300 barg
- Eliminates zero-shift and memory effects common in aluminium-oxide sensors
- Long-term stability and calibration traceable to NPL (UK) and NIST (USA)
- Fully interchangeable sensors for minimal downtime
- Accurate moisture content conversion (ppmV, mg/m³, lb/MMSCF) using optional monitor or dynamic pressure compensation
Detailed Technical Specifications:
- Sample Gas Flow: 0.2–0.5 Nl/min
- Display: Blue LCD graphical display
- Data Logging: Internal memory (~10,000 readings)
- Battery Life: ~24 hours
- Dew‑Point Range: −70…+20 °C (spot checks), −100…−70 °C (online)
- Measurement Units: °C, °F, K dew point & gas temperature; ppmV; g/m³; %RH; lb/MMSCF
- Ingress Protection: IP66 / NEMA 4
- Operating Temp.: −20…+50 °C
- Weight: ~1.5 kg
Applications:
- Dew-point spot-checks in compressed air systems
- Moisture monitoring in natural gas and biogas
- Verification in industrial gas networks
- Use in hazardous areas requiring intrinsic safety
