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:
Pipeline rubber lining:
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 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
Straight pipe length
Pipeline type: upstream ≥5DN, downstream ≥2DN
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 installation method
1. The vortex flowmeter can only be measured in one direction. The installation should pay attention to ensure that the direction of the medium flow is consistent with the direction indicated by the flowmeter arrow.
2. The best installation method of the vortex flowmeter is vertical installation, and the medium passes through the flowmeter from bottom to top. Install the flowmeter on a vertical pipe with the flow direction from bottom to top.
3. When installing horizontally, the flowmeter must be installed in the high pressure zone of the whole system and ensure the corresponding outlet pressure; do not install at the highest point of the pipeline, because the highest point is often gas accumulation, the pipeline is not full, and the outlet cannot be directly emptied.
4. When measuring high temperature fluid, try to use vertical installation; if you have to install horizontally, please install the transmitter part of the flowmeter vertically downwards or horizontally to avoid excessive temperature; pay attention to air flow at installation location Or well ventilated.
5. Straight pipe section requirements: at least 15 times the pipe diameter before the flow meter and 5 times the pipe diameter after the flow meter. If there are elbows, indents, expansions and other sources of interference in front of the flowmeter, the diameter of the flowmeter should be 30–40 times, and the diameter of the flowmeter should be 6 times. The flow meter should be installed upstream of the regulator valve, pressure or temperature sensor.
6. When installing, pay attention to the pipe diameter should be slightly larger than or equal to the inner diameter of the instrument.
7. When using the sealing ring, the inner diameter of the sealing ring should be slightly larger than or equal to the inner diameter of the instrument, and the center of the sealing ring is at the center of the pipe.
Several problems of steam metering and their solutions
Steam is one of the important energy sources for enterprise production. It is the main heat energy for urban central heating and an important indicator for economic accounting. Therefore, the accuracy of steam metering is particularly important.
In order to solve the problem of heating for employees, the company has updated the original boiler equipment, adding 4 new boilers (2 sets of 25t/h, and another 2 sets of 35t/h). The DCS realizes the automatic control of the boiler system, and the product is saturated steam.
Analysis of problems and influencing factors
Starting from the boiler ignition operation in November 2010, the steam flow often shows the maximum value, and the differential pressure signal measured by the differential pressure transmitter exceeds 20 mA. The same is true when the load is low and the actual flow is small. In this case, steam flow measurement does not provide a safety reference for boiler operation, and it cannot be used for cost accounting.
In response to this phenomenon, the design of the project uses a V-cone flowmeter, equipped with an intelligent differential pressure transmitter, and the measurement signal is sent to the DCS for calculation and display.