The measurement is a net measurement (grid measurement) in accordance with VDI regulation 2640. At a sufficient inlet distance of >10D (D = internal diameter of stack) high accuracy is possible with 4 to 8 measuring points. This accuracy is based on our calibration systems for the parameters air-flow velocity and micro pressure for which we are accredited in accordance with EN ISO 17 025 by the authorities.
The drawing shows four grid points with Prandtl (or pitot) tubes which are exposed to the air flow from bottom to top. It is remarkable that flows between 0.3 and 20 m/s can be measured with the method described.
The four measured values from the four grid points are averaged and converted into the unit of volume flow (m3/h). The prerequisite for this is that the inner diameter of the stack is known
The remote field measuring transducer sends its measured data digitally (RS 485) to the central unit which is accommodated preferably in the control room.
Thông số kỹ thuật
| Measuring ranges: |
0 ... 10 m/s
0 ... 15 m/s
0 ... 20 m/s |
| Accuracy |
<0,1 m/s |
| Outputs |
4 ... 20 mA for the parameters:
- flow velocity at all grid points
- average value of flow velocities
- air temperature at the measuring point (-30 ... +140 °C, optionally -30 ... +600 °C)
- barometer pressure at the measuring point (600 ... 1100 mbar)
- status signals for error monitoring
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