How to effectively protect the electromagnetic flowmeter in thunderstorms
In summer, there are many thunderstorms, and thunder will become a great threat to electromagnetic flowmeters in instrument flow measurement. User problems in after-sales feedback In the early stage of using the electromagnetic flowmeter, it was a headache for users to encounter thunderstorms. Every year, due to thunderstorms, more than half of the electromagnetic flowmeter converters were damaged by lightning. .
So how can the user make the converter of the electromagnetic flowmeter not protected from lightning?
Electromagnetic flowmeter is an instrument that uses the principle of electromagnetic induction to measure the flow of conductive fluid according to the electromotive force induced by the conductive fluid passing through an external magnetic field. The structure is mainly composed of magnetic circuit system, measuring catheter, electrode, shell, lining and converter.
The electromagnetic flowmeter can only measure accurately if it has good grounding protection. Maybe in the environment without such interference, the ungrounded does not affect the accurate measurement of the flowmeter, but once the environment changes, the flowmeter cannot work accurately and stably, so It is best to do a good job of grounding protection of the sensor during installation to create a good working environment for the electromagnetic flowmeter.
Summary of lightning protection methods for electromagnetic flowmeters:
1. The length of the arrester grounding wire cannot exceed 1M, and the cross-sectional area is larger than 6MM square multi-strand copper core insulated wire. If there is no ground net nearby, a simple ground net should be made near the arrester. The method is as follows: use three flat steel or angle steel with a length of 1.5M, drive them into the ground in a regular triangle arrangement, and weld the three flat steel with flat steel bars on the top. , Weld the bolts in one corner, and then connect the arrester grounding wire to install the 220VAC lightning arrester grounding wire on the ground plane.
2. The length of the signal cable between the converter and the sensor cannot be greater than 50M, and the signal cable must be sheathed with galvanized pipe. If the galvanized pipe is in the air, the galvanized pipe should be grounded reliably with wires, and the grounding resistance is less than 10.
3. The power supply is 220v one-way alternating current, an air switch is installed in the instrument box, the arrester and the air switch are connected in parallel, and a three-way socket is connected after the wire comes out of the air switch.
Routine maintenance of electromagnetic flowmeter: It is necessary to perform periodic visual inspection of the instrument, check the surrounding environment of the instrument, remove dust, ensure that water and other substances do not enter, check whether the wiring is in good condition, and check whether there is a new strong electromagnetic field equipment near the instrument or whether there is a new installation of wires. across the meter. If the measuring medium is easy to contaminate the electrode or deposit or scale in the measuring tube wall, it should be cleaned and cleaned regularly.
It is hoped that through the analysis, users can make good lightning protection measures after careful reading, which ensures the stable and reliable measurement of the electromagnetic flowmeter and the requirements for accuracy.
