Anemometers

GAOTek offers a various selection of high-quality, affordable and accurate anemometers. An anemometer is a device that is used for measuring the speed and pressure of the wind

Technologies

There are common types of the anemometer. It could either be Velocity anemometer or Pressure anemometer. Velocity anemometer has six kinds of velocity anemometer. It can be Cup anemometers, Vane anemometer, Hot-wire anemometer, Laser Doppler anemometer, Ultrasonic anemometer and ping-pong ball anemometer.

·       Cup Anemometer has three or four cups attached to the horizontal arm, the arm is then attached to a vertical rod. As the wind blows, it is making the cup rotate, making the rod spin. Basically, the stronger the wind blows, the faster the rod spins, the anemometer then counts the number of rotations it made. That is then used to calculate the wind speed. Since wind speeds are not all the same, there are gusts and lulls 

·       Vane Anemometer must have its axis parallel to the direction of the wind. It is made up of a propeller and a tail on the same axis for it to obtain an accurate and precise wind speed direction measurement from the same instrument. The speed of the fan is measured by a rev counter and converted to wind speed by an electronic chip. Although the volumetric flow rate may be calculated if the cross-sectional is known. For situations where the direction of the air motion is always the same, as in ventilating shafts of mines and buildings, wind vanes known as air meters are used. 

·       Hot- wire anemometers are a very fine wire that is electrically heated to some temperature above the ambient. What happens is that air flows past the wire cool the wire and as the electrical resistance of most metals is dependent on the temperature of the metal, a relationship can be obtained between the resistance of the wire and the flow speed. Hot-wire devices can be classified as CCA or Constant Current Anemometer, CVA or Constant Voltage Anemometer and CTA or Constant- Temperature Anemometer. The voltage output from these anemometers is the result of some sort of circuit within the device trying to maintain the specific variable constant, following Ohm’s law. Also, PWM or Pulse -Width Modulation anemometers are also used. This is where the velocity is inferred by the time length of a repeating pulse of current that brings the wire up to specified resistance and then stops until a threshold is reached, at which the pulse is sent again. The hot-wire is delicate, with extremely high- frequency response and fine spatial resolution compared to other measurement methods and as such are almost universally employed for the detailed study of flow in which rapid velocity fluctuations are of interest. The industrial version of the fine-wire anemometer is the thermal flow meter, which basically has the same concept.  

·       Laser Doppler anemometer uses a beam of light from a laser that is then divided into two beams, with one propagated out of the anemometer. What happens is that the particulates flowing along with air molecules near where the beam exits then reflect the light back into a detector that is where it is measured relative to the original laser beam. When the particles are in great motion, they produced a Doppler shift for measuring wind speed in the laser light, which is used to calculate the speed of the particles, and therefore the air around the anemometer.  

·       Ultrasonic Anemometers measures the wind speed based n the time of flight of sonic pulses between pairs of transducers can be combined to yield a measurement of velocity in a 1,2 or 3-dimensional flow. The spatial resolution is given by the path length between transducers. There is an international standard for this process: ISO 16622 Meteorology—Ultrasonic anemometers/thermometers—Acceptance test methods for mean wind measurements is in general circulation. 

·       Ping-pong ball anemometers it is constructed from a ping-pong ball that is attached to a string. How it works is that, when the wind blows horizontally, it presses the ball making it move. The angle between the string-ball apparatus and the vertical has to be measured so it can give an estimated wind speed.

o   There are three kinds of Pressure anemometers. Plate anemometer, Tube anemometer, and Pitot tube anemometer.

·       Plate anemometer is made up of a flat plate suspended from the top so that the wind defects the plate, a square or circular which is kept normal to the wind by a wind vane. How it works is that the pressure of the wind on its face is balanced by a spring, the compression of the spring then determines the actual force which the wind is exerting on the plate, this is then used to read off on a suitable gauge, or on a recorder. This instrument does not respond to light winds, and it is inaccurate for high wind readings.  

·       Tube anemometer is made up of glass u tube containing a pressure gauge with a bent part in the horizontal direction to face the wind and a vertical end remains parallel to the wind flow. Ig there is a wind blow into the mouth of a tube, it causes an increase of pressure on one side of the manometer. The wind over the open end of a vertical tube causes little change in pressure on the other side of the manometer. The exposed part could be mounted on a high pole and requires no oiling or attention for years.  

·       Pitot static anemometers which are a pitot tube with two ports, pitot, and static. The pitot port measures the dynamic pressure of the open mouth of a tube with the pointed head facing the wind, and the static port measures the static pressure of the two lines. The measurement device can be manometers, pressure transducers, or analog chart recorders 

Features

GAOTek Anemometer offers great features:

·       Measurement: Celsius and Fahrenheit

·       Temperature: 0-50C

·       Power Supply: 110 -120V with a built in power supply

·       Response time: Fast and could just take up to two seconds

·       Multi-functions for measurement: m/s, km/h, ft/min, knots, mile/h, CMM (732/733), CFM (732/733)

Also, it includes a high-quality analog display, there is also a rest transmitter build in the device. The intelligent signal processing ensures maximum measurement reliability and stability when using the device this is where the anti- shock built within the device gets handy. 

Applications

·       Cup anemometer is used as the industry standard for wind resource assessment studies and practice

·       Ultrasonic anemometer is used weather stations, ship navigation, wind turbines, aviation and weather buoys, measure gas emissions and ecosystem fluxes.

·       Ping-pong anemometer is used in middle-school level experiments.

·       Plate anemometers have been used to trigger high wind alarms on bridges.

·       Pitot static is used in measuring airspeed of air crafts  

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