Shaw SADP.G Portable Precision Dew Point Meter

Overview

The Shaw SADP.G Portable Precision Dew Point Meter is a field-deployable, intrinsically safe instrument engineered for high-reliability dew point and moisture measurement in industrial gas streams. It employs a proprietary aluminum oxide capacitive sensor—developed and manufactured in the UK by Shaw, a globally recognized leader in humidity metrology with over four decades of heritage in high-stability hygrometric sensing. The sensor core consists of a high-purity aluminum substrate anodized to form a porous alumina layer, coated with a hydrophilic dielectric, and sealed with a microporous gold electrode. This architecture delivers exceptional long-term stability, low hysteresis, and resistance to contamination in non-corrosive gas matrices including compressed air, nitrogen, hydrogen, oxygen, natural gas, and process gases in power generation, petrochemical refining, semiconductor fabrication, and pharmaceutical manufacturing environments.

Key Features

• True portable operation with integrated alkaline battery power—no external supply required for field use
• Intrinsically safe design certified for hazardous area deployment (e.g., Zone 1/21, Class I Div 2)
• Real-time analog pointer display showing simultaneous dew point temperature (°C) and moisture concentration (ppmv)
• One-minute ambient-air auto-calibration—no calibration gas or technician intervention needed
• Proven sensor lifetime exceeding 10 years in clean gas environments; up to 20 years under optimal conditions
• Rapid response time: <1 second for 63% step change in moisture content
• Three calibrated sensor variants available: Purple Dot (−100 to 0 °C DP), Red Dot (−80 to −20 °C DP), and Grey Dot (−80 to 0 °C DP)—SADP.G corresponds to the Grey Dot configuration
• Optional TR extension for ultra-low-range measurement (0–10 ppmv) and digital display (SADP.G-Dg) variants available upon request

Sample Compatibility & Compliance

The SADP.G is validated for use with non-aggressive, non-condensing gases at pressures up to 10 bar (g) and temperatures up to 50 °C. It is not suitable for direct measurement in corrosive, solvent-laden, or particulate-heavy streams without appropriate pre-conditioning (e.g., particulate filtration, coalescing, and pressure regulation). Sample conditioning is achieved via standard PTFE sampling lines and optional flow control valves. All units are manufactured under Shaw’s ISO 9002–certified quality management system. While the instrument itself does not carry CE marking for EU MDR or FDA 21 CFR Part 11 compliance (as it is a standalone analog meter), its measurement traceability aligns with NPL- and NIST-traceable humidity standards. Documentation packages support GLP/GMP audit readiness when deployed in regulated QC/QA workflows.

Software & Data Management

The SADP.G operates as a fully self-contained analog instrument and does not require software, drivers, or connectivity for basic operation. No firmware updates, USB interfaces, or cloud integration are provided. However, for laboratories requiring digital recordkeeping, optional analog-to-digital converters (e.g., 4–20 mA or 0–10 V output modules) can be integrated into external DAQ systems compliant with ASTM D6304, ISO 8573-3, or USP . Calibration logs, operator entries, and environmental conditions may be manually recorded per internal SOPs—consistent with paper-based GLP practices where electronic signatures are not mandated.

Applications

• Verification of dryer performance and compressed air quality per ISO 8573-1 Class 2–4 specifications
• Moisture monitoring in nitrogen blanketing systems for reactor purging and catalyst protection
• Pre-commissioning validation of pipeline drying in oil & gas transmission
• In-process verification of SF₆ insulation gas dryness in high-voltage switchgear
• Quality assurance of packaged medical gases (oxygen, helium, nitrous oxide) prior to distribution
• Field troubleshooting of desiccant and membrane dryer efficiency degradation

FAQ

What gases can the SADP.G measure?
The SADP.G is validated for dry, non-corrosive gases including compressed air, nitrogen, hydrogen, oxygen, argon, helium, natural gas, and SF₆. Avoid exposure to chlorine, ammonia, hydrocarbons, or condensable vapors without inline filtration.
Does the SADP.G require periodic factory recalibration?
No—its patented auto-calibration mechanism enables routine verification using ambient air. Annual verification against a traceable reference standard (e.g., chilled mirror or electrolytic hygrometer) is recommended for ISO/IEC 17025 compliance.
Can the SADP.G be used in high-pressure applications?
Yes—when equipped with a pressure regulator and compatible stainless steel sampling probe, it supports measurements at line pressures up to 10 bar (g). Always depressurize sample gas to atmospheric before entering the sensor chamber.
Is the Grey Dot (G) sensor interchangeable with Red or Purple Dot variants?
No—each dot variant uses a uniquely optimized sensor element with distinct capacitance characteristics and calibration coefficients. Interchange requires full unit reconfiguration and factory recalibration.
What maintenance is required beyond auto-calibration?
Routine inspection of the PTFE sampling line for blockage or moisture ingress, and periodic cleaning of the gold-film sensor surface with isopropyl alcohol and lint-free swabs—per Shaw Technical Bulletin TB-017.