Troubleshooting of magnetic flap (magnetic float) level gauge

The magnetic float of the high-temperature magnetic flap level gauge will demagnetize during use, which will cause the magnetic flap level gauge to fail. The operating temperature of the high-temperature magnetic flap level gauge (especially the high-temperature and high-pressure magnetic flap level gauge) is generally over 180 degrees Celsius, and its installation and detachability are dangerous. The

solution to the demagnetization of the magnetic flap level gauge can be divided into the following aspects:

A. From the design point of view, it is necessary to select appropriate hard magnetic materials. For example, select magnetic materials with a Curie temperature that is more than 20% higher than the operating temperature and ensure that the residual magnetism exceeds the critical value after five years.

B. From the production point of view, the following points should be paid attention to when processing the magnetic float:

1. Cooling measures need to be taken during welding (argon arc welding) to prevent the temperature of the magnetic material of the magnetic float from exceeding the Curie temperature of the magnetic material.
2. The magnetic float is filled with inert gas (such as argon);

C. From the perspective of use, users should do the following:

1. Choose the appropriate model when ordering, so that the operating temperature does not exceed the nominal temperature of the magnetic flap level gauge;

2. During use, the use of the level gauge should be observed at any time (whether it can serve normally), and the actual temperature of the medium should be recorded (I have seen such a situation, the actual use temperature is often higher than the temperature on the parameter table, and the person who designed the parameter table may have overlooked certain factors).

The magnetic float level gauge is a commonly used instrument for measuring liquid level. It has the advantages of simple structure, easy use, stable performance, long service life, and easy installation and maintenance. It is widely used in liquid level measurement, control and monitoring in the fields of petroleum processing, food processing, chemical industry, water treatment, pharmaceuticals, electricity, papermaking, metallurgy, ships and boilers. However, during the detection process, due to the influence of interference factors, the magnetic float ball level gauge will have the following faults, affecting the accuracy of the measurement results. Therefore, let's take a look at the faults of the magnetic float ball level gauge:

1. After the level gauge has been put into use for a period of time, the float is difficult to float and the float moves inflexibly. This is basically caused by iron filings or other dirt on the magnetic float. You can drain the medium first, then take out the float, and eliminate the iron filings or other dirt on the magnetic float.

2. Occasionally, it is found that the float is not sensitive enough to move up and down during on-site adjustment. This is mostly caused by improper installation of the level gauge. At this time, pay attention to whether the centers of the upper and lower flanges are on the same line and whether they are perpendicular to the horizontal plane. Generally speaking, the angle with the horizontal plane should not be less than 87 degrees. If the deviation is large, it may affect the smooth movement of the float.

3. When using an intrinsically safe level gauge, pay special attention to whether the impedance of the level gauge and the safety barrier matches.

4. The adjustment of the magnetic float ball level gauge is normal. After it is put into use, it is found that the float is "sucked" at a certain position for a period of time. This is mainly caused by the fact that the level gauge is too close to the steel plate when it is installed through the steel platform. Therefore, when it is installed through the steel platform, special attention should be paid to the distance between the wall of the level gauge connecting pipe and the cutting edge of the platform.

5. During the use of the level gauge, if the output signal is frequently disturbed or there are interference pulses, it is necessary to check whether the shielding layer of the signal cable is reliably grounded and whether the working connection resistance meets the requirements.

6. When the level gauge is put into use on site, special attention should be paid to opening the upper gate valve first and then the lower gate valve. This is because the bottom of the level gauge connecting pipe is equipped with a thrust spring to protect the float. Otherwise, the effect of the large differential pressure may smash the float and cause the level gauge to be unusable.

7. If the sealed glass tube used for on-site indication is broken due to transportation or other reasons, it can be replaced with a domestic glass tube. But it is best to be vacuumed. Also pay attention to whether the glass tube is vertical to avoid affecting the indication of the indicator.

8. When using the magnetic float level gauge, special attention should be paid. Never use a strong magnet to pull the float up and down outside the connecting pipe for inspection, otherwise the magnetic float will be magnetized and the polarity will be changed, and even the magnetism of the float will be weakened, making it difficult to work normally.