How Does a Liquid Level Sensor Work?

Optical liquid level sensors may provide a reliable and robust solution for an industrial point level sensing application problem. Being solid state, optical liquid level sensors have no moving parts to cause unreliability. Since these sensors use infra-red light, they can be used in environments where a traditional float switch would prove unsuitable.

How Do They Work?

Optical liquid level sensors detect the presence or absence of liquid instead of measuring the liquid level.

Optical liquid level sensors have two key components: a phototransistor that is accurately positioned at the sensor tip base and an infra-red LED.

When the tip is in air, the infra-red light reflects internally round the tip of the phototransistor causing strong optical coupling between the two. In case the sensor tip is immersed in liquid, the infra-red light escapes from the tip reducing the amount of light at the phototransistor which makes the output change state.

Optical liquid level sensors

Advantages and Disadvantages of Optical Liquid Level Sensors

Optical liquid level sensors have many advantages such as solid state design, compact size, reliability, and affordability. These sensors are extremely accurate for point level sensing in high temperature, pressure, and sometimes, corrosive environments, but they are not as useful in applications where continuous level measurement is required.

Optical Liquid Level Sensors from SST Sensing

SST provides a range of optical liquid level sensors for operation in virtually any type of liquid. For applications where an optical liquid level sensor would be suitable, the following level sensors from SST can be considered.

Optomax Digital Liquid Level Sensors

The Optomax Digital liquid level sensors are best suited for space-constrained applications that require a compact, low cost, and low power sensing solution. They are offered in trogamid and polysulphone materials that can handle the majority of liquid types.

Optomax Industrial Glass Liquid Level Sensors

The Optomax Industrial Glass liquid level sensors are designed for more aggressive and corrosive environments and are capable of operating in high-pressure, high-temperature environments, thanks to their stainless steel and glass tip design. They offer industrial supply voltages and outputs that can drive the loads directly.

For applications with more specific requirements, SST can offer a customization service where a solution can be particularly designed to suit your requirements.

SST Sensing Ltd

This information has been sourced, reviewed and adapted from materials provided by SST Sensing Ltd.

For more information on this source, please visit SST Sensing Ltd.

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