Because all kinds of ultrasonic flowmeters can be installed outside the pipe, non-contact flow measurement, the cost of the instrument is basically independent of the size of the pipe to be tested, while other types of flowmeters increase with the increase in caliber, so the cost is increased. The flowmeter is superior to the other functions of the same type of flowmeter. It is considered to be a good large-diameter flow measuring instrument. The Doppler ultrasonic flowmeter can measure the flow of two-phase medium, so it can be used for the measurement of dirty sewage such as sewers and sewage. In power plants, the use of portable ultrasonic flowmeters to measure large pipe diameters such as turbine water inflow and turbine circulating water is much more convenient than in the past. Ultrasonic flow juice can also be used for gas measurement. Pipe diameters range from 2cm to 5m, from a few meters wide open channels, culverts to 500m wide rivers.
In addition, the accuracy of the flow measurement of the ultrasonic measuring instrument is almost independent of the temperature, pressure, viscosity, density and other parameters of the measured fluid, and can be made into non-contact and portable measuring instruments, so it can solve the problem that other types of instruments are difficult to measure. Flow measurement problems for corrosive, non-conductive, radioactive, and flammable and explosive media. In addition, in view of the non-contact measurement characteristics, coupled with reasonable electronic circuits, one instrument can adapt to a variety of pipe diameter measurements and a variety of flow range measurements. The adaptability of ultrasonic flowmeters is also unmatched by other instruments. Ultrasonic flowmeters have some of the above advantages, so it has received more and more attention and has been developed into a series of products and generalization. It has been made into standard, high-temperature, explosion-proof and wet instruments of different channels to adapt to different media. Flow measurement for occasions and different pipeline conditions.
Application of electromagnetic flowmeter
Because electromagnetic flowmeter has its unique advantages, it is widely used in chemical, chemical fiber, food, paper, sugar, water supply and drainage, environmental protection, water conservancy, steel, petroleum, pharmaceutical and other industrial fields. Various acid and alkali salt solutions, mud, pulp, pulp, coal water slurry, corn syrup, fiber pulp, lime slurry, water supply and drainage, brine, hydrogen peroxide, beer, wort, various beverages, black liquor, green liquor, etc. The volumetric flow of the medium.
The main technical parameters
Nominal diameter series DN (mm)
Pipeline PTFE lining:
10,15,20,25,32,40,50,65,80,100,
125,150,200,250,300,350,400,
450,500,600
Pipeline rubber lining:
40,50,65,80,100,125,150,200,250,
300,350,400,500,600,800,1000,
1200
Special specifications can be customized
Flow direction: current output
Positive, negative, net flow
Range ratio: 150:1
Repeatability error: ±0.1 of the measured value
Accuracy level: pipeline type: 0.5 level, 1.0 level
Measured medium temperature
Ordinary rubber lining: -20 ~ +60 ° C
High temperature rubber lining: -20 ~ +90 ° C
PTFE lining: -30 ~ +100 ° C
High temperature PTFE lining: -30 ~ +180 ° C
Rated operating voltage
Pipe type: DN6-DN100≤1.6Mpa, DN125-DN225≤1.0Mpa high pressure can be customized
Conductivity range:
Conductivity of the measured fluid ≥ 5us / cm (integrated)
Most water-based media have a conductivity of 200-800 us/cm, and electromagnetic flow meters can be used to measure the flow rate.
Load resistance: 0 ~ 10mA, 0 ~ 1.5kΩ
4 to 20 mA, 0 to 750 Ω
Digital frequency output
The upper limit of the output frequency can be set to open the bidirectional output of the open collector of the transistor with optical isolation from 1 to 5000HZ. External ≤35V, the maximum current of the collector is 25mA when conducting
Power supply
85～265V, 45～63HZ
Straight pipe length
Pipeline type: upstream ≥5DN, downstream ≥2DN
Connection method
The flowmeter and the pipe are flanged, and the flange connection size should meet the requirements of GB11988.
Explosion-proof mark: mdllBT4
Ambient temperature: -10 ° C ~ +55 ° C
Relative temperature: 5% to 90%
Total power consumption: less than 15W
Daily maintenance (1)
Only need to periodically check the instrument, check the environment around the instrument, remove the dirt, ensure that no water and other substances are inspected, check whether the wiring is good, check whether there is a new strong electromagnetic field device near the instrument or a new installed wire across the instrument. If the measuring medium is easy to contaminate the electrode or precipitate or scale in the measuring tube wall, it should be regularly cleaned and cleaned.
Folding fault finding
After the flowmeter starts to be put into operation or is put into operation for a period of time, it is found that the instrument is not working properly. First, check the external condition of the flowmeter, such as whether the power supply is good, whether the pipeline is leaking or is in a state of non-full pipe, whether there is air bubble in the pipe, whether the signal cable is Damage, converter output signal (ie rear position meter input loop) is open circuit. Remember to blindly disassemble the flowmeter.
Sensor check
Test equipment: one 500MΩ insulation resistance tester, one multimeter.
Test steps:
(1) When the pipeline is filled with medium, measure the resistance between terminals A, B and C with a multimeter. The resistance between A-C and B-C should be equal. If the difference is more than 1 time, there may be leakage of the electrode, condensation on the outer wall of the measuring tube or the junction box.
(2) In the case of lining drying, measure the insulation resistance between A-C and B-C with MΩ meter (should be greater than 200MΩ). Then use a multimeter to measure the resistance of the two electrodes in terminals A and B and the measuring tube (should be in short-circuit communication). If the insulation resistance is small, indicating that the electrode is leaking, the entire flowmeter should be returned to the factory for repair. If the insulation is reduced but there is still more than 50 MΩ and the inspection result of step (1) is normal, the outer wall of the measuring tube may be damp, and the inside of the outer casing may be dried by a hot air blower.
(3) Use a multimeter to measure the resistance between X and Y. If it exceeds 200 Ω, the excitation coil and its lead wire may be open or poorly connected. Remove the terminal block check.
(4) Check the insulation resistance between X, Y and C, which should be above 200 MΩ. If it is lowered, dry the inside of the casing with hot air. In actual operation, the decrease in coil insulation will result in increased measurement error and unstable instrument output signal.
(5) If it is determined that the sensor is faulty, please contact the manufacturer of the electromagnetic flowmeter. The general site cannot be solved and needs to be repaired by the manufacturer.