What Are Liquid Flow Sensors?
Liquid flow sensor is a kind of flow sensor.
Liquid flow sensor
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Liquid flow sensor is a kind of flow sensor.
- Chinese name
- Liquid flow sensor
- Classification
- Distinguish from the medium
- Features
- High accuracy
- Make up
- working principle
Liquid flow
When the measured liquid flows through the sensor, the impeller rotates under the force of the fluid, and its speed is directly proportional to the average flow velocity of the pipeline. The rotation of the impeller periodically changes the reluctance value of the magnetic circuit, and the magnetic flux in the detection coil changes periodically, generating an induced electromotive force with the same frequency as the rotation frequency of the blade.
The practical flow equation of a turbine flow meter is:
Where, ... is volume flow,
... the frequency of the flowmeter output signal;
... the meter factor of the flowmeter.
The relationship curve between the coefficient of the flowmeter and the flow (or the pipe Reynolds number) is shown in Figure 1.1. As can be seen from the figure, the meter coefficient is divided into two sections, namely the linear section and the non-linear section. The linear section is about two-thirds of its working section, and its characteristics are related to the sensor structure size and fluid viscosity. Non-linear section characteristics are greatly affected by bearing friction and fluid viscous resistance. When the flow is below the lower limit of the sensor flow, the meter coefficient changes rapidly with the flow. The pressure loss is approximately squared with the flow. When the flow exceeds the upper limit of the flow, care must be taken to prevent cavitation.
The liquid flow sensor produced by Xuner Instrument has the following characteristics:
nHigh accuracy, generally up to ± 1% R, ± 0.5% R, high precision type can reach ± 0.2% R; (R means reading error)
n Good repeatability, short-term repeatability can reach 0.05% ~ 0.2%, it is precisely because of good repeatability, such as regular calibration or online calibration can get very high accuracy, is the preferred flowmeter in trade settlement;
n Output pulse frequency signal, suitable for total measurement and connection with computer, no zero drift, strong anti-interference ability;
n original pulse frequency range (10Hz 1.5KHz), strong signal resolution;
Wide range ratio, 10: 1 ~ 20: 1;
n Compact and lightweight structure, convenient installation and maintenance, and large circulation capacity;
nSuitable for high pressure measurement, no need to make holes in the meter body, easy to make high voltage instruments;
n There are many types of special-purpose sensors, which can be designed as various types of special-purpose sensors according to the special needs of users, such as low-temperature type, two-way type, underground type, and sand-mixing type;
n can be made into a plug-in type, suitable for large-caliber measurement, small pressure loss, low price, can be continuously removed, convenient installation and maintenance.
LWGY sensor general index table 3.1 |
Tested medium | No impurities, low viscosity, no strong corrosive liquid |
Implementation standards | Turbine flow sensor (JB / T9246-1999) |
Verification Regulations | Turbine flowmeter (JJG1037-2008) |
Instrument caliber And connection method | Flange connection type | DN15-DN200 |
Threaded connection | DN4-DN50 |
Clip-on connection | DN4-DN200 |
Flange standard | Conventional standard | GB / T9113-2000 |
Other standards | International pipe flange standards | Such as German standard DIN, American standard ANSI, Japanese standard JIS |
Domestic pipe flange standards | Such as Ministry of Chemical Industry Standards, Ministry of Machinery Standards |
Thread specifications | General specifications | Inch pipe thread (external thread) |
Other specifications | Internal thread, spherical thread, NPT thread, etc. |
Accuracy class | ± 1% R, ± 0.5% R, ± 0.2% R (requires special) |
Repeatability | 0.15%, 0.1%, 0.03% |
Range ratio | 1:10; 1:15; 1:20 |
Test conditions | Verification device | Standard meter method liquid flow verification device Liquid mass calibration device for static mass method |
Environmental conditions | Ambient temperature | 20 |
Relative humidity | 65% |
Conditions of Use | Medium temperature | T1 (general type, standard configuration) | -20 + 80 |
T2 (high temperature, customized) | -20 + 120 |
T3 (high temperature, customized) | -20 + 150 |
Ambient temperature | -20 + 60 | Relative humidity | 5% 90% |
Atmospheric pressure | 86Kpa 106Kpa |
Instrument caliber (mm) | Meter factor (times / L) | Lower frequency limit (HZ) | Frequency upper limit (HZ) |
DN 4 | 16000 | 177.8 | 1111.1 |
DN 6 | 8200 | 227.8 | 1366.7 |
DN 10 | 1800 | 100.0 | 600.0 |
DN 15 | 830 | 138.3 | 1383.3 |
DN 20 | 600 | 133.3 | 1333.3 |
DN 25 | 212 | 58.9 | 588.9 |
DN 32 | 150 | 62.5 | 625.0 |
DN 40 | 77 | 42.8 | 427.8 |
DN 50 | 27 | 30.0 | 300.0 |
DN 65 | 12.1 | 23.5 | 235.3 |
DN 80 | 6.1 | 16.9 | 169.4 |
DN 100 | 4.3 | 23.8 | 238.9 |
DN 125 | 3.1 | 21.5 | 215.3 |
DN 150 | 2.2 | 18.3 | 183.3 |
DN 200 | 1.2 | 26.7 | 266.7 |
Table 3.3.2 LWGY sensor pressure rating |
Connection method | Caliber range | Conventional pressure rating | Special pressure resistance rating |
Flange connection type | DN4-DN50 | 4.0MPa | 10MPa and below |
DN65-DN200 | 1.6MPa | 10MPa and below |
Threaded connection | DN4-DN40 | 6.3MPa | - |
DN50-DN80 | 1.6MPa | - |
Clip-on connection | DN4-DN40 | - | 42MPa and below |
DN50-DN80 | - | 25MPa and below |
DN100-DN150 | - | 16 MPa and below |
DN200 | - | 12 MPa and below |
