The electromagnetic flowmeter consists of an electromagnetic flow converter and an electromagnetic flow sensor. The separate type also requires a special double-shielded cable to connect the converter and the sensor. There are two kinds of electromagnetic flowmeters in common use: integrated structure and separated type. Can be used in specified explosion-proof locations.
The sensor of the split electromagnetic flowmeter should be installed vertically, and the fluid should flow from the bottom up to meet the solid and liquid conditions. The reason is that if there is solid matter in the medium, it is easy to precipitate. In addition, there are fish and weeds in the pipeline. Fish swimming in the pipeline will cause the output of the flowmeter to swing back and forth; the swing of the weeds hanging near the electrode will also cause the output of the flowmeter to be unstable. Today we focus on the split – type electromagnetic flowmeter
The split electromagnetic flowmeter can prevent negative pressure from being generated in the sensor due to improper setting of the negative pressure pipeline. When both the upstream and downstream valves of the flowmeter are closed at the same time, if the temperature of the fluid is higher than the air temperature, it will shrink after cooling, which may cause the pressure in the pipe to form a negative pressure. The negative pressure caused the liner to peel off from the metal conduit, causing electrode leakage.
Add a negative pressure prevention valve near the split electromagnetic flowmeter and open the valve to connect to atmospheric pressure to prevent negative pressure in the sensor. When a vertical pipeline is connected downstream of the split electromagnetic flowmeter, if the upstream valve of the flow sensor is used to close or adjust the flow, a negative pressure will form in the sensor measurement tube. To prevent negative pressure, add back pressure or use a downstream valve to regulate and close the flow.
Installation of the split electromagnetic flowmeters requires proper maintenance space. Large-caliber flowmeters are often installed in instrumentation wells. For the convenience of pipeline installation, wiring, inspection and maintenance, appropriate space is required. For the convenience of observation, wiring and maintenance, the instrument should be installed at a certain height from the ground to facilitate cleaning and installation.
Installation and external environment requirements of split electromagnetic flowmeter:
- Flowmeters should not be installed in places where the temperature changes greatly or the equipment is exposed to high temperature radiation. If necessary, thermal insulation and ventilation measures should be provided.
- The flowmeter should be installed indoors. If it must be installed outdoors, it should be protected from rainwater, flooded water and sun exposure. Moisture and sun protection measures must be taken.
- In order to facilitate the installation, maintenance and maintenance, ample installation space is required around the flowmeter.
- The installation field of the flowmeter should avoid strong magnetic fields and strong vibration sources. If the pipeline is vibrated, there should be fixed pipeline supports on both sides of the flowmeter.