The air volume measuring device test bench adopts the method of "constant static pressure" to measure relevant parameters and air volume. Set static pressure value: When the test fan is running, the current static pressure value changes, the PID instrument reads the current static pressure value through the sensor, and compares it with the set static pressure value. If the current static pressure value does not reach the set static pressure value, the PID instrument automatically adjusts the speed of the auxiliary fan and controls the air volume of the auxiliary fan so that the current static pressure value reaches the set static pressure value. When the static pressure value is stable, measure the relevant parameters required to calculate the air volume, and calculate the air volume of the test fan.
Measurement principle:
The anti-blocking wind speed and air volume measurement device is based on the S-shaped pitot tube measurement principle. When there is air flow in the pipe, the windward surface is impacted by the air flow, and the kinetic energy of the air flow is converted into pressure energy here, so the pressure in the front pipe is high.Its pressure is called "full pressure". Since the leeward side is not affected by the airflow, the pressure in thepipe is the static pressure in the air pipe, and its pressure is called "static pressure". The difference between total pressure and static pressure is called differential pressure, and its magnitude is related to the wind speed in the pipe. The greater the wind speed, the greater the differential pressure; When the wind speed is small, the differential pressure is also small, and the relationship between the wind speed and the differential pressure conforms to the Bernoulli equation.
The wind speed and air volume measurement device is divided into various structures according to different use occasions, different working conditions and installation methods.
Anti-blocking display air volume measuring device:
Based on the measurement principle of the Pitot tube;
High measurement accuracy, good linearity and importance;
Can be installed at any angle;
High cost performance, very economical operating costs;
Negligible pipeline pressure loss, effectively reducing fan energy consumption;
The inner section of the pipeline is distributed in a multi-point array, and the measurement speed is average.
Backrest tachymeter, flute tachymeter:
Both are non-standard tachometers.
The flute pipe is installed in the pipe to measure the average flow rate of the airflow at one time. The double flute tube is to assemble the full pressure measuring tube and the static pressure measuring tube together.
There is a row of full pressure measuring holes on the upstream side of the full pressure tube, and a group of static pressure measuring tubes are opened on the back of the static pressure tube. The principle of the backrest tube is similar to that of the pitot tube, and the dynamic pressure value is obtained by measuring the difference between the total pressure and the static pressure. It has the property of dynamic pressure amplification and needs to be calibrated before use.
Dual Venturi Tachymeter:
For power plant boiler supply air and flue gas flow rate measurement;
The result is simple;
The pressure loss is small, only accounting for about 1% of the volume of differential pressure generated;
The requirements for straight pipe sections are not strict;
The dynamic pressure magnification is the highest, which is several times or even ten times that of the pitot tube and the uniform velocity tube device;
Each double-venturi velocimeter is calibrated before leaving the factory, and a test report is attached.
Generally, no on-site calibration is required after installation.
Cross-sectional flowmeter:
It can meet the installation requirements of any secondary air duct, does not require on-site calibration, is not affected by irregular fluids or even multi-directional rotating airflow, and has low pressure loss
1. The S-type anti-blocking structure design ensures that under the condition that the pipeline medium concentration is greater than 50*/*, the speed measuring device will not be blocked during long-term operation.
2. The pressure loss is the smallest, greatly reducing the power consumption of the fan, and the energy saving effect is obvious.
3. The core components are made of special grinding materials to ensure continuous use for more than one overhaul cycle.
4. Accurate and stable signal output, good linearity and repeatability.
5. The multi-point grid method is used to measure large-sized pipelines, and the multi-point arrangement of equal sections can accurately measure the gas flow rate.
6. The requirement of straight pipe section is very low. In the working condition of 1.5D straight pipe section, the linearity and accuracy can still be guaranteed.
7. The differential pressure signal is large. Compared with the Pitot tube and Annubar, it can generate a differential pressure greater than 2 times.
Test items:
The air volume measuring device is mainly used to detect air purifiers and related household air purification devices, etc. It is designed, manufactured and installed by the China Academy of Building Research. Test items include:
1) Air volume;
2) Wind pressure;
3) Input power.
| GB/T 1236-2000 |
Performance Test of Standardized Air Ducts for Industrial Ventilators |
| GB/T 2624.3-2006 |
Measurement of full-pipe fluid flow with differential pressure devices installed in pipes of circular cross-section - Part 3: Nozzles and Venturi nozzles |
Audited Supplier 
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