Thermo-Anemometer

What is a Thermo Anemometer?

A thermo anemometer is a device, a measuring instrument for checking wind speed [gr. Anemos]. Anemometers are available in many different designs and equipment variants. In the following text, you may find some information meant to facilitate the decision when purchasing a thermo anemometer. PCE Instruments is also happy to develop individual measurement solutions for wind monitoring for special applications. Simply contact us.

First of all, to make the right choice of a thermo anemometer, the application should be clarified. If this is unclear, just contact us and we’ll give you our assistance. When selecting a thermo anemometer, the design and the measuring principle are primarily in focus. For exact measurements of small wind speeds, the thermal anemometers are often used. In case of a thermal anemometer, also referred to as a hot wire anemometer, an electrical resistor with a defined current and a constant voltage is heated. If a wind flows past the sensor element of the anemometer, this resistor cools down. By measuring the electrical variables of current and voltage, the resistance at a corresponding flow velocity can be calculated. In thermal anemometers, the temperature is often also measured by means of a separate sensor element.
Thermal anemometers are often used to measure the draft flow or to measure flow velocities in ducts. The measurement with a thermal anemometer is often a measurement for directed flows.

Another anemometer used to measure directional flows is the vane anemometer. In contrast to the hot wire anemometer, this wind meter has a wheel, which is driven by the wind. Depending on the model, the actual measurement takes place then via a Hall sensor which registers the individual revolutions, or via an optical sensor, which scans a reflex mark attached to the impeller. A significant difference compared to the hot wire anemometers is that here the moving parts are needed to measure the wind. A disadvantage is that a certain wind speed is required till a measurement is carried out. This initial flow is often between approx. 0.4 m / s ... 0.6 m / s, depending on the design. Thus, it is not possible to measure very small wind speeds with vane anemometers.

Another type of the moving anemometers is the cup anemometer. Anemometers of this type are used when the wind or a flow should be measured regardless of the direction. These anemometers are often applied for stationary wind measurement and wind monitoring.

A special design of the anemometer is the Pitot tube anemometer. A Pitot tube anemometer calculates a flow velocity based on the difference between two pressures. Via a special Pitot tube probe, the anemometer measures the ambient pressure in a duct and the incoming pressure that affects the probe. The difference between the two pressures gives the flow rate. Pitot tube anemometers are often used at very high flow velocities. These anemometers are known from racing or aircraft construction.
If the design and the measuring principle corresponding to the measurement task of the anemometer have been selected, the device with the correct display has to be found.

Here, as well as for many other measuring instruments from the assortment, there are many different models.
For example, there are models which merely display the flow velocity and give the user the information about the measured value. Furthermore, there are thermo anemometers, which have interfaces, which make it possible to transmit the measured value to a PC. In addition, there are thermo anemometers, which can be used as a multifunction device. These thermo anemometers can, for example, additionally determine temperatures or flows in watercourses. Wind warning systems complete the assortment of anemometers. Special thermo anemometers from the assortment of PCE Instruments are able to calculate, besides the wind velocity, also the volumetric flow in ducts.
The user only has to set the duct area in the device and the thermo anemometer displays the volume flow directly. In addition to the thermo anemometers, which consist of the entire measuring chain, i.e. the sensor + display, there are also just sensors available in the range of the PCE Instruments products. The thermo anemometer sensors usually have a signal output, which can be evaluated by external evaluation devices such as data loggers, alarm units, displays or PLCs.
These thermo anemometers are often used for stationary wind measurements. In accordance with the application, we would like to recommend the following anemometer types. This overview can help you find the right anemometer for the current application.

Application Anemometer Type

-Low wind speeds in ducts with little access Hot wire thermo anemometer
-Wind speeds in ducts at vent outlet Vane anemometer
-High flow velocity in a duct Pitot tube anemometer
-Control of air-conditioning systems Hot wire or vane anemometer
-Leak testing / draft measurement Hot wire anemometer
-Wind qualification for wind power plants Cup anemometer
-Wind testing in sailing Vane or cup anemometer

Should you have any further questions regarding thermo anemometers from PCE Instruments, you can always call the technical consulting hotline of PCE Instruments: UK: 02380 - 987 030 or US: (561) 320-9162. The colleagues will ask you specific questions about your application and suggest the best suited products for the solution of your measurement task. Should the thermo anemometers from our standard range not be suitable for your application, we would be pleased to work out a solution for your task. For example, we are able to develop autarkic anemometers with remote access for stationary wind measurements.