Magnetic level indicator is a device used to monitor liquid level or liquid height. It utilizes the magnetic principle to achieve accurate measurement and display of liquid level.

Sewage Magnetic Level Indicator
Sewage Magnetic Level Indicator

What’s in a magnetic level indicator?

Indicator pipe

The indicator pipe on a magnetic level gauge(UHZ Liquid Float Magnetic Level Gauge) is a transparent or semi-transparent pipe mounted vertically on the level gauge to indicate the height or level position of a liquid. Inside the indicator pipe is a magnetic indicator, usually a small removable magnetic marker or indicator, which is connected to a float in the level gauge.


Floats are built into the inside of the indicating pipe and move with the liquid level. It is usually made of a material that is less dense than the liquid, and is therefore able to float on the surface of the liquid and follow changes in level.

Magnetic device

This is the part inside or associated with the float, usually a small magnetic object such as a small magnet or a small marker containing magnetic material, that is mounted inside the indicator pipe of the magnetic level gauge. This magnetic indicator will be connected to the float and move up and down the indicating pipe as the level changes. It is designed to provide a visual indication of liquid level through magnetic interaction without direct contact with the liquid. The movement of the magnetic indicator will be visualized by the observer in the indicator pipe of the level gauge to show the current level height or position.

External magnetic indicators

An external magnetic indicator works in a similar way to a magnetic level gauge, but it is not a component built into the inside of the level gauge. Instead, the external magnetic indicator is part of the magnetic level gauge system and is usually mounted on the outside of the level gauge.

It usually consists of a magnetized marker or indicator that is mounted on the outside of the level gauge, usually on an indicator pipe or transparent enclosure. The external magnetic indicator is usually a small movable magnetic marker connected to an internal float through a transparent or translucent window in the wall of the level gauge.

The float inside the level gauge moves up and down in response to changes in liquid level and indicates the height or position of the liquid level through the external magnetic indicator on the transparent wall. This design allows the observer to clearly observe changes in liquid level through the external magnetic indicator without direct contact with the liquid, providing an intuitive and safe way to monitor liquid level.

Does the magnetic level indicator need a power supply?

A magnetic level indicator usually does not require an external power supply. It works based on the interaction of a magnetic device and a float for indicating the liquid level height without the need for an external power supply to support its basic function.

The operating mechanism of the magnetic level indicator relies on the movement of the magnetic device on the float and indicates the position of the liquid level by interacting with an external magnetic indicator, allowing the operator to visualize the level from outside the pipeline without having to come into direct contact with the liquid. This principle of operation does not require external power or battery support.

Therefore, magnetic level indicators are typically passive devices that do not require an external power source, and they achieve liquid level indication and monitoring through the magnetic principle.

Magnetic level indicator material

ComponentCommon Materials
Indicator PipeStainless Steel, Carbon Steel, Plastic
FloatPlastic, Fiberglass
Magnetic DeviceIron, Steel, Permanent Magnet Materials
External IndicatorStainless Steel, Special Alloys
Materials of Magnetic Level Indicator Components

Advantages of magnetic level indicators

When compared to other level monitoring technologies, magnetic level indicators offer the following advantages:

  1. Stability and reliability: Magnetic level indicator is composed of simple components, such as float and indicator tube, so it has high stability and reliability and is not easy to be affected by external influences.
  2. Accuracy: Magnetic level indicator can provide relatively high level measurement accuracy, which makes it a reliable tool to accurately monitor liquid level changes.
  3. Unaffected by the environment: Compared with some sensor technologies, magnetic level indicators are not affected by environmental factors such as temperature, pressure, corrosion or vibration, making them more durable in harsh environments.

Where are magnetic level indicators used?

Magnetic level indicators are widely used in many industrial and commercial applications, primarily for monitoring the level or height of a liquid. Common application scenarios for them include, but are not limited to:

  1. Chemical industry: for monitoring the level of liquids in chemical reaction tanks, storage tanks and pipelines to ensure the stability and safety of the production process.
  2. Oil and gas industry: Used for liquid level monitoring in oil tanks, oil wells and pipelines to ensure effective management of oil and gas storage.
  3. Pharmaceutical and Food Processing: It is used in reaction tanks and storage tanks in the production of pharmaceuticals, in boilers, and in processing equipment in the food industry to ensure that the production process complies with standards.
  4. Aerospace: Used in fuel oil tanks or hydraulic systems in aerospace vehicles and airplanes to monitor fluid levels in real time.
  5. Energy industry: in power plants, nuclear power plants and water treatment plants for monitoring and managing liquid storage and transportation.
  6. Marine and Ship: Level monitoring of fuel tanks and hull compartments in ships to ensure safe operation of ships.
Magnetic level indicator for oil tanks
Magnetic level indicator for oil tanks
Magnetic level indicator for water treatment
Magnetic level indicator for water treatment


Magnetic level indicators utilize the magnetic principle to monitor liquid levels and are widely used in the chemical, petroleum, and aviation industries to ensure safe and reliable liquid levels. This device is simple, reliable and suitable for a variety of environments, making it an important liquid level monitoring tool.

Apure provides water quality analysis, flow meter, level measurement, pressure measurement, temperature measurement, ozone generator and other instruments. If you have questions, please feel free to contact us.