Bosworth Instrument Training Sheet Series

Anemometers / Air Flow Meters

Alternate Terms for Anemometers

·         Air Flow Meters

·         Air Velocity Meters

·         Wind cups

What is an Anemometer?

Anemometers measure the speed (velocity) of moving air. Thermo-Anemometers also measure temperature by way of a thermometer located in the Anemometer sensor. The measurement units for Anemometers include:  Feet per minute (ft/min), meters per second (m/s), kilometers per hour (km/hr), miles per hour (mph), nautical miles per hour (knots), and Beauforts.

What is CFM?

Cubic Feet per Minute is the unit of measure for Air Volume measurements. Air velocity measurements provide wind-speed information but sometimes it is important to know the volume of air movement. This is accomplished by applying the size of the duct (or other air passageway) to the velocity of the moving air.

Do you have a meter that will calculate and display both CFM and CMM.

·         The new HD300 CFM/CMM meter displays air flow in CFM/CMM or Air Velocity plus ambient temperature. It will also store up to 8 easy to set area dimensions in the meter’s memory for quick and easy measurements in duct work, ceiling vents and more.  It also has an IR Infrared thermometer built in.

What is the difference between Vane and Hot-Wire Anemometers?

Vane Anemometers use a remote fan (vane) that freely rotates in response to air flow. The vane movement equates to air velocity readings that can be displayed on a meter. The Hot Wire Anemometer sensor is a special wire whose resistance fluctuations are translated into air velocity readings that can be displayed on a meter.

Which applications are best for Vane and Hot-Wire types?

Hot-Wire Anemometers offer a slim sensor (0.5" diameter), well suited for accessing small openings and crevices (engine compartments and small ventilating systems). Hot-Wire Anemometers don't have vulnerable, movable mechanical parts that can wear or become damaged over time. Vane Anemometers are lower cost and allow easy visual inspection of the moving vane (great for air duct and fume hood applications).

Typical Anemometer Applications

·         Air duct measurements • Automobile engine and passenger

·         Positive pressure readings in clean compartment testing rooms • Ionizer flow output  monitoring

·         Fume hood testing and verification • Ventilation system inspection

 I’m looking for calculations to compute area for square and round ducts.

·         See this pdf sheet for useful formulas >more>>