Overview of Magnetic Flap Level Gauge
The magnetic flap level gauge is a key instrument for liquid level measurement. It uses a two-color magnetic flip column combined with a magnetic float controller to visually indicate liquid level.
This type of level gauge is widely used in towers, tanks, spherical vessels, containers, and heat-treatment furnaces. It is suitable for liquid level detection in chemical machinery and industrial equipment.
The magnetic flip-column liquid level transmitter is equipped with an inlet valve tube, which can be mounted at the top or on the side of the vessel. This structural design ensures accurate and stable liquid level measurement.
Main Functional Modules of the Magnetic Flap System
The main components of the upgraded magnetic turning column system include:
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Turning column liquid level indicator
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Float level gauge
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Liquid level transmitter
These components work together to provide visual indication, signal transmission, and level control.
Working Principle of Magnetic Control and Signal Transmission
The magnetic control module is either integrated into the centrifugal pump pressure controller or connected to it via a small chain. When the pressure controller of the centrifugal pump interacts with the magnetic control module, the liquid level indicator moves and drives the magnetic flap to rotate.
The liquid level gauge contains a magnetic float ball that moves in sync with the liquid level. The water level sensor generates a signal, and the resistance value changes according to the pump pressure controller. A smart transmitter then converts this resistance signal into a standard output signal of 4–50 mA for remote monitoring.
Measurement Principle Based on Float Law and Magnetism
The magnetic flap level gauge operates based on the float law and magnetic coupling. It is connected to the storage tank via a flange.
Inside the equipment, a two-color cylindrical magnetic float ball responds to changes in the electromagnetic field. The contact position of the float ball corresponds directly to the actual liquid level inside the storage tank, providing a clear visual indication.
Installation and Commissioning Procedures
During installation, magnetically conductive materials should be kept away from the gauge to avoid interference. The electrical heating temperature must be determined according to the material properties of the medium.
If the gas–liquid phase connection diameter is large, the flange of the Sanchang liquid level transmitter should be precisely centered. Before operation, the magnetic column should be reset to the milky white position using magnetic adjustment tools.
First, open the liquid phase shut-off valve, followed by the high-level liquid phase shut-off valve. Observe the rise of the level gauge. As the liquid level inside the vessel increases, the magnetic float ball—made of rare-earth permanent magnet steel—moves upward accordingly.
Visual Indication and Color Display Mechanism
Through magnetic coupling, the float ball transmits signals to the magnetic turning column indicator. The indicator uses red and white color coding:
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When the liquid level rises, the turning column rotates to bright red
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When the liquid level drops, it returns to milky white
The red-and-white contrast clearly marks the liquid level position, ensuring easy and intuitive reading. The system features strong sealing performance, effectively preventing leakage and maintaining reliable operation under high-temperature and high-pressure conditions.
Suitable Media and Harsh Working Conditions
The magnetic flap level gauge is particularly suitable for measuring substances that are:
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High temperature
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High pressure
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Toxic
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Hazardous
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Strongly corrosive
It provides stable and reliable performance in demanding industrial environments.
Sealing Requirements and Measurement Limitations
Strict sealing requirements must be met when the measured substance comes into contact with the pump pressure switch. However, due to the physical characteristics of viscous media, accurate measurement of highly viscous substances may not be achievable under certain conditions.
