Anemometers to measure the speed of wind or a gas stream, and flowmeters to measure the flow rate of a liquid or gas; available in a variety of configurations.

Vane anemometers are mechanical velocity instruments, often described as windmills or propellers. The axis of a vane anemometer is parallel to the wind direction (horizontal). The fan speed is measured by a revolutions counter and converted to a wind speed measurement.

Digital vane thermoanemometers may be pre-calibrated, traceable to NIST, and offer a choice of measurement units (ft./min., m/s, mph, km/hr., knots, CFM, and CMM).

Hot wire anemometers use an electrically heated wire to help calculate air speed. The wire is cooled by the air flow and the known resistance of the metal is used to calculate the flow speed.

Although somewhat delicate, hot wire anemometers are used to study turbulent or rapid velocity fluctuation flows.

In the laboratory, hot-wire anemometers can be used to measure outside wind speed, air velocity, and temperature in hoods and enclosures, and slight gas movement in ductwork.

Other types of anemometers include:

• Laser Doppler anemometers
• Ultrasonic anemometers
• Acoustic resonance anemometers
• Pressure anemometers (tube and plate)

Some flowmeters measure and monitor the flow of gases. Sometimes used with gas chromatography systems, these instruments may be rated for use with flammable and explosive gases.

Common types of flowmeters with industrial applications include:

• Obstruction type (differential pressure or variable area)
• Inferential (turbine type)
• Electromagnetic
• Positive displacement
• Fluid dynamic (vortex shedding)
• Anemometer
• Ultrasonic
• Mass flowmeter (Coriolis force)