CMC TMS-H-P-20 Portable Electrolytic Dew Point Analyzer

Overview

The CMC TMS-H-P-20 is a portable, high-stability electrolytic dew point analyzer engineered for trace moisture measurement in industrial gas streams where reliability, low maintenance, and field-deployable precision are critical. Utilizing the well-established phosphorus pentoxide (P₂O₅) electrolytic sensing principle, the instrument quantifies water vapor concentration by electrolyzing H₂O molecules captured on a hygroscopic P₂O₅ film deposited between dual platinum electrodes. The resulting electrolysis current is directly proportional to the partial pressure of water vapor—enabling continuous, real-time dew point determination with high reproducibility across demanding process environments. Designed and manufactured in Germany, the TMS-H-P-20 meets stringent requirements for use in compressed air systems, natural gas transmission, SF₆ insulation gas monitoring, semiconductor purge lines, and hydrogen fuel cell feed gas qualification.

Key Features

• Electrolytic P₂O₅ sensor with platinum electrodes and Hastelloy measuring cell—ensuring chemical resistance to aggressive or corrosive gas matrices including H₂S, CO₂, and halogenated compounds.
• FEP-sealed glass substrate assembly provides long-term sensor stability and minimizes drift under variable thermal and pressure conditions.
• Compact, battery-operated portable design optimized for on-site verification, commissioning support, and periodic audit measurements without requiring external power or gas conditioning infrastructure.
• Integrated flow control system maintains precise 20 NL/h sample gas throughput—critical for maintaining sensor response time and measurement linearity.
• Wide operating pressure range (0.1–0.5 barg) accommodates both low-pressure sampling and regulated process line tapping without external pressure regulation.
• Robust 6 mm Swagelok®-compatible Hastelloy fittings ensure leak-tight connections and compatibility with standard industrial gas handling hardware.

Sample Compatibility & Compliance

The TMS-H-P-20 is validated for use with non-condensing, non-reactive gas streams—including nitrogen, argon, helium, hydrogen, oxygen, compressed air, SF₆, and natural gas (with appropriate pre-filtration). It is not suitable for gases containing condensable hydrocarbons, silicone vapors, or high concentrations of acidic or oxidizing species that may degrade the P₂O₅ film. The analyzer complies with IEC 61294 (dew point measurement methods), EN 12021 (compressed breathing air specifications), and supports adherence to ISO 8573-1 Class 1–4 moisture purity grading when deployed per standardized sampling protocols. Its construction and calibration traceability align with GLP documentation practices for laboratory and field-based QA/QC workflows.

Software & Data Management

The TMS-H-P-20 operates as a standalone analog/digital hybrid instrument with local LCD display and configurable 4–20 mA output. While it does not include embedded data logging or wireless connectivity, its analog output is compatible with third-party SCADA, DCS, or LIMS platforms supporting HART or Modbus RTU integration via optional interface modules. Calibration certificates are supplied with NIST-traceable reference standards, and full audit trails—including calibration date, operator ID, and environmental conditions at time of verification—are maintained per internal lab SOPs. The device supports 21 CFR Part 11-compliant data integrity when integrated into validated electronic record systems using qualified acquisition software.

Applications

• Verification of desiccant dryer performance and regeneration cycles in compressed air systems (ISO 8573-1 Class 2–4).
• Moisture monitoring in SF₆ switchgear to prevent dielectric breakdown and arc flash hazards.
• Pre-commissioning checks of pipeline purging in petrochemical and LNG facilities.
• In-line verification of hydrogen purity per ISO 14687 Grade A/B specifications for fuel cell applications.
• Field validation of membrane or refrigerant dryer efficiency in pharmaceutical nitrogen generation skids.
• Supporting ASTM D6680 (standard test method for trace moisture in gaseous fuels) and ISO 8573-3 (moisture measurement procedures).

FAQ

What is the recommended calibration interval for the TMS-H-P-20?
CMC recommends annual calibration using certified zero and span standards; however, frequency should be adjusted based on usage intensity, exposure history, and quality system requirements (e.g., every 6 months in GMP-regulated environments).
Can the sensor be exposed to liquid water or condensation?
No. Direct contact with liquid water or sustained condensation will permanently damage the P₂O₅ film and invalidate measurement integrity. Sample gas must remain fully gaseous throughout analysis.
Is the TMS-H-P-20 suitable for measuring moisture in natural gas with H₂S content?
Yes—provided total H₂S remains below 50 ppmv and particulate filtration (≤1 µm) is implemented upstream. Higher concentrations require application-specific risk assessment and potential sensor protection strategies.
Does the instrument require carrier gas or zero-air supply?
No. The TMS-H-P-20 operates exclusively on the measured sample gas stream and does not require auxiliary purge or zero-gas sources.
How does pressure variation affect dew point readings?
Dew point is a thermodynamic property independent of pressure; however, the instrument’s specified 0.1–0.5 barg range ensures stable sensor hydration kinetics and accurate current-to-concentration conversion. Outside this range, measurement uncertainty increases due to altered diffusion dynamics across the P₂O₅ layer.