Level Sensor Different Types and Applications

A liquid level sensor is a device used to monitor, maintain and measure the level of liquids (and sometimes solids). Once the liquid level is detected, the sensor converts sensed data into an electrical signal. The main types of liquid level sensors are ultrasonic liquid level sensors, capacitive liquid level sensors, photoelectric liquid level sensors, microwave optical sensors, etc., and their applications are as follows:

Ultrasonic Liquid Level Sensor

It is used to detect the content of viscous liquid substances and the content of volume substances. They work by generating audio waves in the frequency range 20 to 200 kHz and then copying these waves back to the transducer. The response of ultrasonic sensors is affected by turbulence, pressure, humidity and temperature. In addition, the transducer must be appropriately increased for better response. It can be used to control level, fine solids in mining and powders, food and beverage industries, and chemical processing.

Capacitive Liquid Level Sensor

It is used to detect liquid level changes of mud and aqueous solutions, the sensor is used to check the liquid level change by using a probe made of PTFE insulated wire, and use the liquid level change to cause capacitance changes. The detected capacitance value determines whether the location of the sensor is in a water state or an anhydrous state. Furthermore, stainless steel probes are extremely responsive, making them suitable for measuring non-conductive particles or materials with low dielectric constants. These types of sensors are very easy to use and clean because they don't have any moving parts. They are commonly used in applications such as chemical, water treatment, food, level monitoring in the battery industry, involving high pressure and high temperature.

Photoelectric Level Sensor

Photoelectric level sensor can detect liquids, including stable substances, interfaces between two immiscible liquids, and the presence of deposits. Their work is based on transmission variability of infrared light emitted by infrared LEDs. Using high-energy infrared diodes and pulse modulation methods, light-generating interference can be reduced. On the other hand, photoelectric level sensors utilize high-intensity lasers that can be injected into dusty environments and notice liquid substances. They are typically used in leak detection and tank level measurement.

Microwave Optical Sensor

This type of sensor is suitable for different temperature, pressure, dirty and humid environments since microwaves can easily pass through these situations without involving the energy transfer of air molecules. Microwave optical sensors can detect conductive water and metallic substances. Time domain and pulse reflection methods are primary measurements. They are commonly used in vapor, humid, dusty environments and systems with different temperatures.

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