Anemometer, also known as anemometer, is an instrument for measuring air flow rate. It can be widely used in various fields, such as electric power, steel, petrochemical, energy conservation, etc. In daily life, many industries need to use anemometers, such as fan manufacturing. Wind, wind and air volume measurements are required to ensure normal operation.

First, anemometer use precautions

1. Do not expose the probe and the anemometer body to the rain. Otherwise, there may be electric shock, fire and personal injury.

2. Do not touch the sensor part of the probe while the anemometer is energized. Otherwise, it will affect the measurement results or cause damage to the internal circuit of the anemometer.

3. When the anemometer is not used for a long time, remove the internal battery. Otherwise, the battery may leak and the anemometer may be damaged.

4. Do not wipe the anemometer with volatile liquids. Otherwise, it may cause deformation and discoloration of the anemometer housing. When there is stain on the surface of the anemometer, use a soft fabric and a neutral detergent to wipe.

5. Do not place the anemometer in a place subject to high temperatures, high humidity, excessive dust and direct sunlight. Failure to do so may result in damage to internal components or deterioration of anemometer performance.

6. Do not drop or press the anemometer. Failure to do so will result in malfunction or damage to the anemometer.

7. It is forbidden to use an anemometer in a flammable gas environment.

8. Please use the anemometer correctly according to the requirements of the instruction manual. Improper use can result in electric shock, fire, and damage to the sensor.

9. In use, if the anemometer emits an unusual smell, sound or smoke, or if liquid flows into the anemometer, shut down the battery immediately. Otherwise, there is a danger of electric shock, fire and damage to the anemometer.

10. Do not disassemble or modify the anemometer. Failure to do so may result in electric shock or fire.

11. Do not touch the internal sensor part of the probe.

12. Do not place the anemometer probe in a flammable gas. Failure to do so may result in fire or even explosion.

Second, the classification of anemometer

According to the principle: thermal anemometer, ultrasonic anemometer, impeller anemometer, three-cup anemometer, windmill anemometer, pitot tube anemometer, etc.

According to the shape of the probe: there is a pointing anemometer, a non-directional anemometer

According to the test range and test parameters: medium and high temperature anemometer, micro wind speed meter, multi-parameter environmental test meter, etc.

Third, anemometer product application field

It can measure wind speed and air temperature. This anemometer can be used in indoor air quality/industrial health environment, environmental testing in pipelines, performance tuning of HVAC equipment, etc.

working principle:
A speed measuring instrument that converts a flow rate signal into an electrical signal that also measures fluid temperature or density. The principle is that a thin wire (called) electrically heated is placed in the airflow, and the amount of heat dissipation in the airflow is related to the flow rate, and the heat dissipation causes a temperature change to cause a resistance change, and the flow rate signal is converted into an electrical signal. It has two working modes: 1 constant current. The passing current remains unchanged. When the temperature changes, the resistance changes, so the voltage at both ends changes, thereby measuring the flow rate; 2 constant temperature type. The temperature remains the same, such as maintaining 150 ° C, the flow rate can be measured according to the current applied. The thermostatic type is more widely used than the constant current type.
The length is generally in the range of 0.5 to 2 mm, and the diameter is in the range of 1 to 10 μm. The material is platinum, tungsten or platinum-rhodium alloy. If a thin metal film (thickness less than 0.1 micron) is used instead of the metal wire, it is a hot film anemometer, which functions similarly to the hot wire, but is mostly used to measure the liquid flow rate. In addition to the ordinary single line type, it can also be a combined two-wire or three-wire type to measure the velocity component in all directions. The output electrical signal is amplified, compensated and digitized and input into the computer to improve the measurement accuracy, automatically complete the data post-processing process, and expand the speed measurement function, such as simultaneously completing the instantaneous value and the time average value, the combined speed and the sub-speed, the turbulence and Measurement of other turbulence parameters. Compared with the pitot tube, the anemometer [1] has a small probe volume, small interference to the flow field, fast response, and can measure unsteady flow rate; it can measure very low speed (such as as low as 0.3 m/s).
When a thermal probe is used in turbulent flow, airflow from all directions simultaneously impacts the thermal element, which can affect the accuracy of the measurement. When measured in turbulent flow, the temperature indicator of the thermal anemometer is often higher than that of the rotary probe. The above phenomenon can be observed during the pipeline measurement process. Depending on the design of the management pipe turbulence, it can occur even at low speeds. Therefore, the anemometer measurement process should be performed in the straight section of the pipe. The starting point of the straight line should be at least 10 × D (D = pipe diameter, in CM) before the measuring point; the end point is at least 4 × D behind the measuring point. The fluid section must not have any obstructions (angles, rehangs, objects, etc.).

product instructions:
1. Before using, observe whether the pointer of the meter refers to the zero point. If there is an offset, gently adjust the mechanical adjustment screw of the meter to return the pointer to zero point;
2. Put the correction switch in the off position
3. Insert the measuring rod plug into the socket, the measuring rod is placed vertically upwards, the screw plug is pressed tightly to seal the probe, the “correction switch” is placed at the full position, and the “full adjustment” knob is slowly adjusted to make the meter pointer full. Degree position
4. Set the “correction switch” to “zero position” and slowly adjust the “coarse adjustment” and “fine adjustment” two knobs so that the meter pointer points to the zero position.
5. After the above steps, gently pull the screw plug to expose the probe (the length can be selected according to the need), and make the red dot on the probe face the wind direction. According to the meter reading, check the calibration curve to find out. Measured wind speed;
6. After measuring a few points (about 10 minutes), the above steps 3 and 4 must be repeated to standardize the current in the meter. After the test, the “correction switch” should be placed in the off position.

1. Principle of anemometer:

The basic principle of the anemometer is that a thin metal wire is enclosed in a fluid and heated by an electric current, making its temperature higher than that of the fluid. Therefore, the wire anemometer is called “hot-wire”. When the fluid flows through the wire in a vertical direction, it will take part of the heat away from the wire and cause the wire temperature to clear. According to the forced convection heat exchange theory, the relation between the heat Q dissipated by the hot-wire and the velocity v of the fluid can be derived. Wire is usually constructed of platinum, rhodium, tungsten and other metals with high melting point and good ductility. Common wire diameter 5 m, length 2mm, minimum probe diameter 1 m, length 0.2mm. According to different USES, the hot wire probe is also made into double wire, triple wire, oblique wire and v-shaped, x-shaped, etc. In order to increase the strength, sometimes use metal film instead of metal wire, usually in a thermal insulation substrate coated with a thin metal film, known as hot film probe. The hot-wire probe must be adjusted before use. Static calibration was conducted in the specialized standard wind tunnel, measuring the velocity and the relationship between the output voltage and drawing standard curve, dynamic calibration was conducted in the pulsating flow field is known, or in the anemometer heated circuit and a pulse signal, check the frequency response of hot-wire anemometer, if poor frequency response available corresponding compensation circuit to improve them.

The velocity measurement range from 0 to 100m/s can be divided into three sections: low speed: 0 to 5m/s; Medium speed: 5 to 40m/s; High speed: 40 to 100m/s. The thermal probe of the anemometer is used for the accurate measurement of 0 to 5m/s, and the rotary probe of the anemometer is used for the optimal measurement of the velocity of 5 to 40m/s. The pitot tube gives the best results at high speeds. An additional criterion for the correct selection of anemometer velocity probes is temperature, usually the temperature of the thermal sensor of the anemometer is approximately + -70c. The spinner probe of the special anemometer can reach 350C. Pitot tubes are employed to +350C and above.

2. Anemometer usage:

1) observe whether the pointer of the electricity meter point to zero before use. If there is deviation, the mechanical adjustment screw of the electricity meter can be adjusted gently to return the pointer to zero.

2) put the correction switches in the broken position.

3) insert the measuring rod plug into the socket, the measuring rod is placed vertically upward, the screw plug is pressed to make the probe sealed, the “correction switch” is placed in the full position, and slowly adjust the “full adjustment” knob to make the meter pointer point to the full position.

4) place the “calibration switch” at the “zero position” and slowly adjust the “coarse adjustment” and “fine adjustment” knobs to make the meter pointer to the zero position.

5) after the above steps, gently pull the screw plug to expose the measuring rod probe (length can be selected according to the need), and make the red point on the probe face the wind direction, according to the meter reading, check the correction curve, you can find out the measured wind speed.

6), after measuring several minutes (about 10min), the above steps 3 and 4 must be repeated once to standardize the current in the meter.

7) after the test, the “calibration switch” shall be placed in the inoperative position.