Liquid flow sensor

1 classified editing

The liquid flow sensor can be divided into a corrosive liquid flow sensor and a non-corrosive liquid flow sensor. This is only differentiated from the medium, and is also the first item to be selected in the application. [1] After determining the nature of the liquid, it is based on the needs of our own application, a metered liquid flow sensor or an analog signal output flow sensor, and today's metering type generally has a pulse signal (Sacera water flow sensor). The analog signal output is now more of a digital signal output (such as a reed switch), it can also be converted into a current and voltage signal, and the analog quantity only provides an analog (switch) quantity, which cannot be measured. Relatively speaking, it is relatively crude, and the accuracy of a liquid flow sensor without a metering type is high, and the flow rate of the simulated amount is also a matter to be considered by the switch liquid flow sensor. Divided by accuracy, there are water level (B and A levels, usually within 2% to 3% of errors, there is a measurement certificate), beyond the current general use of 5% -10% electronics To use when the switch signal, or water heating, such as electric water heaters, drinking fountains, coffee machines, gas water heaters, water flow sensor (Sailing water flow sensor). Summarized in one sentence: starting from the medium, the second from the use of demand into the water, three from the beginning of precision, you can choose to the liquid flow sensor you want. [2]

2 working principle edit

When the measured liquid flows through the sensor, under the action of the fluid, the impeller is forced to rotate, and its rotation speed is proportional to the average flow velocity of the pipeline. The rotation of the impeller periodically changes the magnetic resistance of the magnetic circuit, and the magnetic flux in the detection coil periodically changes, generating an induced electromotive force having the same frequency as the rotation frequency of the blade. After amplification, conversion and processing are performed.

Turbine flow meter utility flow equation is:

Where, ... is the volume flow,;

......Flowmeter output signal frequency,;

... the meter factor of the flow meter,.

The relationship between the flow meter coefficient and flow rate (or pipeline Reynolds number) is shown in Figure 1.1. As can be seen from the figure, the meter coefficient is divided into two sections, namely a linear section and a non-linear section. The linear segment is approximately two-thirds of its working range, and its characteristics are related to the size of the sensor structure and the viscosity of the fluid. The characteristics of the nonlinear segment are greatly affected by bearing friction and fluid viscosity resistance. When the flow rate is lower than the sensor lower limit, the meter coefficient changes rapidly with the flow rate. Pressure loss and flow are approximately squared. When the flow exceeds the upper flow limit, care should be taken to prevent cavitation.

3 Product Features Edit

The liquid flow sensor produced by Xuner Instruments has the following features:

n High accuracy, generally up to ±1%R, ±0.5%R, high-precision type up to ±0.2%R; (R refers to reading error)

n Good repeatability, short-term reproducibility of 0.05% to 0.2%, due to good repeatability, such as frequent calibration or online calibration can get extremely high accuracy, in trade settlement is the preferred flow meter;

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;

n wide range ratio, 10:1~20:1;

n Compact and lightweight structure, convenient installation and maintenance, large circulation capacity;

nApplicable to high pressure measurement, the meter body does not need to open the hole, easy to make high-pressure instrument;

n There are many types of special-purpose sensors, which can be designed for various types of special-purpose sensors according to the special needs of users, such as low-temperature type, two-way type, downhole type, sand-specific type, etc.;

n can be made into insert type, suitable for large diameter measurement, low pressure loss, low price, can be continuously flow out, easy installation and maintenance.

4 Technical parameter editing

LWGY Sensor General Specifications Table 3.1

Measured medium

No impurities, low viscosity, no strong corrosive liquid

Executive standard

Turbine flow sensor (JB/T9246-1999)

Verification procedure

Turbine Flow Meter (JJG1037-2008)

Instrument caliber

And connection method

Flange connection type

DN15-DN200

Threaded type

DN4-DN50

Clip connection type

DN4-DN200

Flange standard

General standards

GB/T9113-2000

Other standards

International pipe flange standard

Such as German standard DIN, American standard ANSI, Japanese standard JIS

Domestic pipe flange standard

Such as the 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 level

±1%R, ±0.5%R, ±0.2%R (required)

Repeatability

≤0.15%, ≤0.1%, ≤0.03%

Range ratio

1:10;1:15;1:20

Verification conditions

Verification device

Standard table method liquid flow verification device

Static mass method liquid flow calibration device

Environmental conditions

Ambient temperature

20°C

Relative humidity

65%

Conditions of Use

Medium temperature

T1 (General, Standard)

-20°C～+80°C

T2 (high temperature, custom)

-20°C～+120°C

T3 (high temperature, custom)

-20°C to +150°C

Ambient temperature

-20°C～+60°C

Relative humidity

5% to 90%

Atmospheric pressure

86Kpa～106Kpa [3]

5 meter factor band editing

Instrument diameter (mm)

Meter factor (times/L)

Lower frequency limit (HZ)

Frequency 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

6 pressure rating edit

Table 3.3.2 LWGY Sensor Pressure Rating

Connection method

Range of caliber

Conventional pressure rating

Special pressure rating

Flange connection type

DN4-DN50

4.0MPa

10MPa and below

DN65-DN200

1.6MPa

10MPa and below

Threaded type

DN4-DN40

6.3MPa

-

DN50-DN80

1.6MPa

-

Clip connection type

DN4-DN40

-

42MPa and below

DN50-DN80

-

25MPa and below

DN100-DN150

-

16 MPa and below

DN200

-

12 MPa and below