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
Vortex flowmeter analysis and solution
6. The connection problem between the secondary instrument and the subsequent instrument. Due to the problem of the subsequent instrument or the maintenance of the subsequent instrument, the mA output circuit of the secondary instrument is interrupted. For this type of secondary instrument, this part is mainly related to the problem 2. Especially for the subsequent recorders, in the case that the recorder cannot be repaired for a long time, it is necessary to pay attention to shorting the output of the secondary meter.
7. The circuit always has no indication due to the failure of the secondary instrument flat-axle cable. Due to long-term operation, coupled with the influence of dust, the flat-axle cable is faulty, and the problem can be solved by cleaning or replacing the flat-axis cable.
8. For the problem 7, the main problem is that the secondary instrument shows that the fixing screw of the meter head is loose, causing the head to sink, the pointer and the case friction are large, the movement is not working, and the problem is solved by adjusting the meter head and re-fixing.
9. Use environmental issues. In particular, the sensor part installed in the well is affected by the humidity of the environment, which causes the circuit board to be damp. This part is mainly related to questions 2 and 2. Through the corresponding technical improvement measures, the sensor part with large humidity is re-separated from the probe part and the conversion part, and the separate type sensor is used. Therefore, the working environment is good, and the instrument has been running well.
10. Due to the poor adjustment of the site, or due to the actual situation after the adjustment. Due to the on-site vibration and noise balance adjustment and sensitivity adjustment is not good. Or because of the re-allocation of the situation after a period of operation after the adjustment, causing the indication problem, this part of the reason is mainly related to questions 4 and 5. Use an oscilloscope, plus the combined process operation, and re-adjust.
Mass flow meter
Since the volume of the fluid is affected by parameters such as temperature and pressure, it is necessary to give the parameters of the medium when the flow rate is expressed by the volume flow. In the case of changing media parameters, it is often difficult to achieve this requirement, resulting in distortion of the meter display value. Therefore, mass flow meters have been widely used and valued. Mass flow meters are available in both direct and indirect versions. Direct mass flow meters are measured using principles directly related to mass flow. Currently used mass flow meters such as calorimetric, angular momentum, vibratory gyro, Magnus effect and Coriolis force. The indirect mass flow meter is obtained by directly multiplying the density meter by the volumetric flow rate to obtain the mass flow rate.
In modern industrial production, the operating parameters such as temperature and pressure of the flowing working fluid are continuously improved. In the case of high temperature and high pressure, due to the material and structure, the application of the direct mass flowmeter is difficult, and the indirect quality is encountered. Flowmeters are often not suitable for practical applications because they are limited by the range of humidity and pressure. Therefore, a temperature-pressure-compensated mass flowmeter is widely used in industrial production. It can be regarded as an indirect mass flow meter. Instead of using a density meter, it uses the relationship between temperature, pressure and density. It uses a temperature and pressure signal to calculate the density signal by function, and multiplies it by the volume flow. Mass Flow. At present, temperature and pressure-compensated mass flowmeters have been put into practical use. However, when the measured medium parameters vary widely or rapidly, it will be difficult or impossible to correctly compensate, so further study the mass flow rate applicable in actual production. Meters and densitometers are still a topic.
Chen's above-mentioned common structural principle of flowmeters is much better than various types of flowmeters, such as various helium flowmeters and trough flowmeters for open channel flow measurement; flowmeters suitable for large-caliber flow measurement; measuring laminar flow Laminar flowmeter; related flowmeter for two-phase flow measurement; and laser method, nuclear magnetic resonance flowmeter and various tracer methods, dilution method flow measurement, etc. With the development of technology and practical application needs, the new flowmeter will continue to emerge more types of flowmeters.