The device and principle of operation of the liquid level sensor in simple language

  • Dec 14, 2020

Technological processes in the modern world require frequent measurements of the volume of fuel materials, filling with water and other liquid substances. A liquid level sensor is used to control the filling of any container with liquid in automatic mode. In this article, we will consider the main types and principle of separation of level gauges.

Device and principle of operation

Today there are a huge number of liquid level sensors that differ in both design and measurement method. In view of what, we will consider the device using the example of the simplest float model of the level gauge.

Structurally, a float liquid level sensor consists of the following components:

The device and principle of operation of the liquid level sensor in simple language
  • float 1 - designed to interact with the surface of the liquid;
  • bellows 2 - is a sensitive corrugated element capable of retaining its properties under repeated mechanical deformations;
  • flange 3 - used for connection with the mounting surface, allows to increase the fastening density
  • microswitch 4 - triggered by the movement of the float in the geometric plane; to prevent interaction with moisture, it is placed in a sealed case.
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  • gasket 5 - used to seal the hole, prevents liquid from flowing out of the container.

The principle of operation of such a sensor is based on the Archimedean force of any liquid.

The principle of operation of the liquid level sensor

When the sensor is placed in a container with liquid, the float interacts with the surface. Due to the buoyancy force, the float is pushed outward and is in the same position as the level.

When the liquid is in the middle position, the float will remain in the neutral position, the signal from the switch does not go to the control panel or alarm panel. If the tank is filled to position 2, the float rises higher and switches the microswitch to the appropriate position.

If the liquid in the tank drops below the nominal level, the float will move to the lower position 3 and move the contacts of the microswitch. Each time the sensor outputs a corresponding signal about the degree of filling, however, the principle of operation will differ depending on the type of device.