The Hot-Wire Anemometer is the most well known thermal anemometer, and measures a fluid velocity by noting the heat convected away by the fluid. The core of the anemometer is an exposed hot wire either heated up by a constant current or maintained at a constant temperature (refer to the schematic below). In either case, the heat lost to fluid convection is a function of the fluid velocity.Typically, the anemometer wire is made of platinum or tungsten and is 4 ~ 10 µm (158 ~ 393 µin) in diameter and 1 mm (0.04 in) in length. Typical commercially available hot-wire anemometers have a flat frequency response (< 3 dB) up to 17 kHz at the average velocity of 9.1 m/s (30 ft/s), 30 kHz at 30.5 m/s (100 ft/s), or 50 kHz at 91 m/s (300 ft/s).

      The principal of a hot wire anemometer is based on  a heated element from which heat is extracted by the colder impact airflow. The temperature of the hot wire is kept constant via a regulating switch, and the current (amp draw measured internally) is directly proportional to the air velocity. When using a hot wire in turbulent air streams the measured results can be impacted by by turbulent airflow striking the measurement sensor from multiple directions. This could indicate a higher measured value than a vane probe. This characteristic is typically prevalent in ducts where turbulent airflow can occur even at very low velocities.

 

 

*Measurement items: Air velocity, Air temperature ,Air Quantity
*Measurement range:
   ----Air velocity: 0~30m/s
   ----Air temperature:0~45º C, 32~113º F (± 2º C)
*Resolution: 0.1º C, 0.001m/s
*Max/Min Reading

*Average/Current Reading

*Data Hold

*Backlight Display

*Low Battery lndication

*Manual/Auto Power Off

*Power: 6F22 9V
*Dimension: 67.5*45.8*30.2mm