CFM Airflow Meters and Anemometer HVAC Equipment: Professional Airflow Velocity Profilers

Quick Answer

Silver Automation Instruments supplies CFM airflow meters and anemometer type HVAC instruments for duct velocity profiling, filter monitoring, and ventilation testing. Standard insertion thermal mass flow meters cover 0.2 to 40 m/s in ducts from DN100 to DN2000 with 4-20 mA HART or RS485 Modbus output. Send your duct size, airflow range in CFM, air temperature, and signal type for a model selection and price.

How a CFM Airflow Meter Works in HVAC Ducts

An insertion thermal mass flow meter has two sensor elements in the probe. One element reads gas temperature. The other element is heated. Air flowing across the heated element removes heat. The meter measures that cooling effect and converts it to mass velocity. Because the probe has a built in PT100 temperature sensor, the electronics compensate for air temperature changes in real time. The flow computer converts velocity to CFM when you enter the duct width, height, or diameter.

Anemometer HVAC Equipment vs Fixed Airflow Meters

A handheld anemometer is fast for traverse testing on grilles and diffusers. It works well for spot checks and commissioning. A fixed CFM airflow meter from Silver Automation Instruments gives you a continuous 4-20 mA signal. The fixed meter connects to a BMS or PLC. It tracks filter loading, fan performance, and exhaust air velocity without opening the duct. In practice most maintenance teams carry a portable anemometer for field checks and install one fixed thermal mass meter on each critical duct.

Common Applications We See on Customer Sites

We supply airflow meters for AHU duct monitoring in Southeast Asia and the Middle East. A recent order came from an HVAC contractor in Qatar who needed an insertion airflow meter for a 400 mm duct. The duct operated at 45 °C with air velocity from 3 to 28 m/s. We supplied a thermal mass flow meter with Modbus RTU, a local display, and a 316 stainless steel probe. Other uses include cleanroom ventilation in Malaysia, paint booth exhaust in Vietnam, and wastewater aeration air lines in the Philippines.

Key Parameters for a Quote

To select the right unit, our engineers need the duct inner diameter in mm, the normal and maximum airflow rate in CFM or m3/h, the air temperature in °C, and the required signal output. Standard units accept 24 VDC and output 4-20 mA plus HART. The enclosure rating is IP65 with an aluminum housing. If the duct carries humid air, dust, or oil mist, we recommend a purge or a different probe material. For hazardous area installation we can supply ATEX Zone 1 or Zone 2 certification.

Accuracy and Field Calibration

Most thermal mass airflow meters from Silver Instruments have an accuracy of ±1.5 percent of reading plus 0.5 percent of full scale under reference conditions. This spec matters when you balance a duct network or monitor minimum outdoor air. Every unit ships with a calibration certificate. Some customers request a five point calibration across their actual velocity range. That option reduces site disputes during commissioning.

Why Fixed CFM Meters Save Time on HVAC Jobs

A fixed CFM airflow meter removes the need to open duct access panels for repeated spot checks. The probe stays in the duct and sends velocity data to the control room. You can log data, set alarm limits, and trend filter pressure over months. This is useful for hospitals, commercial towers, and any plant with strict ventilation codes. A portable anemometer remains useful for initial traverse checks, but the fixed meter gives the long term record.

FAQ

Can a CFM airflow meter be installed in an existing duct without cutting the duct?
Yes. Most insertion probes fit through a 25 mm ball valve or weld-on compression fitting. You drill one hole, install the fitting, and insert the probe to the correct depth.

What is the difference between CFM and m3/h?
CFM is cubic feet per minute. Cubic meters per hour is the metric equivalent. Multiply CFM by 1.699 to get m3/h. Our flow computers can display either unit.

Do these meters work in hot or humid air streams?
Standard probes handle air up to 120 °C. Optional probes extend to 200 °C. For humid air, condensation on the probe can affect the reading. We recommend a longer insertion length and stable upstream flow.

Can I use the same meter for nitrogen or exhaust gas?
Yes. Thermal mass flow meters measure gas mass velocity and can be calibrated for air, nitrogen, oxygen, or other gas mixtures. Tell us the gas composition when you request a quote.

What signal output should I choose for a BMS or PLC?
Most HVAC panels accept 4-20 mA analog. If you want digital data, choose RS485 Modbus RTU. HART is useful for setup and diagnostics but it is not always required for normal operation.

Get a Quote from Silver Automation Instruments

Send your duct size in mm, airflow range in CFM or m3/h, air temperature in °C, and required signal output. You can reach Silver Automation Instruments by phone at +86-25-68650347, on Whatsapp at +86-25-52155837, or on WeChat at +86 15365082610. A sales engineer will reply with model selection, lead time, and price within one working day.

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