QDF-6 Digital Hot-Wire Anemometer

Overview

The QDF-6 Digital Hot-Wire Anemometer is a compact, portable thermal anemometer engineered for reliable measurement of low-velocity airflows in diverse environmental and industrial settings. Based on constant-temperature hot-wire anemometry (CTA), the instrument detects convective heat loss from a heated platinum or tungsten sensor element suspended in the airflow — a principle directly correlating cooling rate to local air velocity. This method delivers high sensitivity at low flow rates (0.01–5 m/s), making the QDF-6 especially suited for HVAC commissioning, indoor air quality (IAQ) assessments, ventilation duct surveys, and laboratory-scale airflow characterization where precision at sub-1 m/s velocities is critical. Its robust analog signal conditioning and digital conversion architecture ensure stable output under variable ambient conditions, while its lightweight design supports extended handheld operation during field audits.

Key Features

• Thermal sensing principle with platinum-based hot-wire probe for high repeatability in laminar and transitional flow regimes
• Real-time 4-digit LCD display with 0.01 m/s resolution and automatic zero-tracking compensation
• Fast dynamic response (≤3 seconds to 95% of final reading) suitable for transient airflow monitoring
• Integrated rechargeable power system compatible with DC 5–6 V input, enabling >8 hours of continuous operation per charge
• Rugged ABS housing (190 × 90 × 40 mm; 380 g) with IP54-rated front panel for dust and splash resistance during field use
• No external calibration required under standard operating conditions; factory-calibrated traceable to national metrological standards

Sample Compatibility & Compliance

The QDF-6 is optimized for gaseous media — primarily ambient air — across non-corrosive, non-explosive environments. It is not rated for use with high-humidity saturated air (>85% RH), aggressive chemical vapors, particulate-laden exhaust streams, or explosive atmospheres (ATEX/IECEx). The device operates within atmospheric pressure range 970–1040 hPa and ambient temperature 0–50 °C, aligning with ISO 7726 (Ergonomics of the thermal environment — Instruments for measuring physical quantities) and ASTM D1072 (Standard Test Method for Air Velocity in Ducts). While not certified to FDA 21 CFR Part 11 or GLP/GMP Annex 11, its measurement stability and documented calibration history support compliance with internal QA/QC protocols in HVAC-R, cleanroom validation, and environmental health & safety (EHS) reporting workflows.

Software & Data Management

The QDF-6 operates as a standalone field instrument without embedded Bluetooth or USB data logging. However, its analog voltage output (0–5 V DC proportional to 0–30 m/s) is compatible with third-party data acquisition systems (e.g., National Instruments DAQmx, LabVIEW, or Arduino-based loggers) for time-series recording and post-processing. Users may integrate readings into Excel-based audit trails or LIMS platforms via manual entry or simple serial-to-USB adapters (optional accessory). Firmware updates are not applicable; calibration verification intervals follow ISO/IEC 17025 recommendations — typically every 12 months or after mechanical shock or exposure beyond operational limits.

Applications

• HVAC system balancing and duct traverse surveys in commercial buildings, hospitals, and laboratories
• Indoor air quality (IAQ) monitoring per ASHRAE Standard 62.1 and EN 13779
• Ventilation rate verification in classrooms, offices, and public assembly spaces
• Agricultural microclimate assessment in greenhouses and controlled-environment agriculture (CEA) facilities
• Biosafety cabinet face velocity checks (preliminary screening, per NSF/ANSI 49)
• Educational demonstrations of fluid dynamics principles in physics and environmental engineering curricula

FAQ

Is the QDF-6 suitable for outdoor wind speed measurement?
It is not recommended for unsheltered outdoor use due to lack of weatherproofing beyond IP54 and absence of wind vane stabilization or gust averaging algorithms.
Can the probe be replaced or cleaned?
Yes — the hot-wire probe is a user-replaceable module; gentle cleaning with isopropyl alcohol and lint-free swab is permitted if contamination affects baseline stability.
Does the instrument meet NIST-traceable calibration requirements?
Each unit ships with a manufacturer’s calibration certificate referencing national primary standards; full NIST-traceable recalibration services are available through authorized service centers.
What is the expected sensor lifetime under normal use?
With proper handling and avoidance of mechanical impact or condensation, the hot-wire element typically maintains specification performance for ≥2 years.
Is there a version with data logging capability?
No — the QDF-6 is a dedicated real-time indicator. For logging functionality, consider the QDF-6L variant (discontinued) or upgrade to the QDF-8 series with SD-card storage and timestamped CSV export.