It is generally believed that the volume flow measured by the electromagnetic flowmeter is not affected by the viscosity and temperature of the liquid. However, the test proves that it will be affected. The conclusion of the following test example
1. The influence of liquid viscosity
Modulated sugar, water solution, and glycerin, water solution is 5, 15, 70, and 20mm2/s (cSt) four-speed viscosity test fluid, respectively, DN10 and DN40 calibers of 8 manufacturers, and the lining is ceramic polytetrafluoroethylene plastic, and PFA fluorine Eighteen plastic instruments were used for the viscosity influence test and compared with water when the reference liquid was 20℃.
The flow experiment range includes laminar flow zone, transition zone, and turbulent flow zone, and the maximum flow velocity is 5m/s. In this viscosity range, the average cross-conversion is 0.7%-1.6%, and the biggest change is nearly 4%.
2. The influence of liquid temperature
Change the water temperature from 20℃ to 45℃, test the above 18 instruments, the highest flow rate is 5m/s, and the average influence is shown in Table 5-9
| Diameter/mm | Lining material | After the test, re-calibrate under the reference conditions, compared with the calibration value under the reference conditions before the temperature test, the overall offset |
1. Water conductivity is 500uS/cm 2. The ambient temperature is 20℃ |
||
| Ceramics | PTFE | PFA | |||
| Influence/%*(10℃)-1 | |||||
| DN10 | 0.09 | 0.12 | -0.22 | 0.3 | |
| DN40 | 0.11 | 0.07 | 0.06 | 0.2 | |