Haven't used a magnetic flap level gauge yet? Learn how it works and its applications in this article.

The Application and Advantages of Magnetic Flap Level Gauges in Industrial Automation

Magnetic flap level gauges occupy a vital position in industrial automation. Their unique structure and principles have made them the preferred device for level measurement in numerous industries. They are most notable for their intuitive and reliable design, allowing operators to quickly read level data without extensive training.

Another major advantage of magnetic flap level gauge is their simple structure. Compared to other types of level gauges, they lack complex electronic components and consist primarily of a float, a measuring tube, and a flap display. This streamlined design not only reduces failure rates but also significantly cuts maintenance needs. What’s more, they require no power source, making them particularly suitable for industrial environments with unstable or hazardous power supplies.

Their high corrosion resistance also boosts their popularity. Manufacturers offer models with diverse materials—including stainless steel, titanium alloy, and polytetrafluoroethylene lining—based on operating environments. This lets them withstand harsh conditions like acidic/alkaline environments, high temperatures, and high pressures, extending their service life far beyond conventional glass tube level gauges.

• Main pipe (measuring tube): A vertically mounted manifold connected to the container’s bottom (liquid phase) and top (gas phase), with liquid level aligned to the container’s height.

• Magnetic float: A sealed component with a permanent magnet inside, floating on the liquid surface in the main pipe.

• Magnetic flap indicator: Closely spaced, pivoted cylindrical flaps (one bright color, one neutral color) with embedded small magnets.

Level Change Drives the Float: When the container’s liquid level rises or falls, the gauge’s main pipe liquid level changes synchronously, moving the internal magnetic float up or down.

• Magnetic Coupling: The float’s internal magnet generates a moving magnetic field as it moves.

• Flap Rotation: When the float passes a flap on the magnetic flap indicator, their magnets couple (attract/repel), flipping the flap 180 degrees.

• Color Indication: Flipped flaps show bright colors (e.g., red) below the liquid level and neutral colors (e.g., white) above; the boundary marks the precise level.

• Remote Transmitter: Sensors (e.g., magnetostrictive, reed switch) on the gauge’s main pipe convert level signals to 4-20 mA for control room monitoring.

• Switch Alarm: A magnetic switch set at a specific height on the gauge triggers alarms when the float reaches it, controlling pump start/stop.