Ultrasonic Level Switch
Reliable solutions exist for detecting the presence of materials in a vessel or space that reduce moving parts in contact with the material and can alert you to a high or low point critical for safety and other industrial applications. These products are resilient, often require no calibration, and are self-cleaning. Read on for our beginner guide to ultrasonic level switches. These simple explanations are meant to help you choose the best product for your needs.
What is an ultrasonic level switch?
An ultrasonic level switch is a device to indicate the presence or absence of a material at a certain point, or level, within a container. While some ultrasonic level switches can be used to detect the presence of a wide variety of materials, such as slurries or bulk solids, some are suited specifically to liquid detection, such as ultrasonic liquid level switches. With these switches, there are no moving parts in contact with the material they are detecting, making them more hardy and durable. These switches also work regardless of the chemical composition of the liquids being measured.
It is important to distinguish level switches from level sensors. Switches are ideal for detecting materials at a high or low point in a container or space for purposes of inventory control, whereas sensors provide continuous measurements where highly specific, precision measurements are required, such as in transferring materials in commercial transactions.
How does an ultrasonic level switch work?
Ultrasonic level switches work by sending a high frequency, inaudible sound signal from one piezoelectric crystal, made of ceramic material, to another across a small space. Imagine a U-shape where the long sides of the U represent the transmitting signal origin and the receiving signal receiver. The speed of the sound signal traveling from the transmitting crystal through a short gap to its destination at a receiving crystal indicates the presence of material in the gap. Ultrasonic liquid level switches use the principle of sound traveling at a greater speed through liquid versus an attenuated speed through air to detect the presence of a liquid in the gap space at a certain point. When a liquid is present, the received signal is quite strong, versus a very weak signal received when liquid is absent. A relay is switched depending on the strength of the signal.
Switches meant to detect a wet gap with liquids are called high-level and actuate their relays based on liquid detection. Switches meant to detect a dry gap are called low-level, and actuate their relays based on gas, or air, in the gap.
Ultrasonic liquid level switches may be installed vertically or horizontally in vessels, pipes, or other spaces, such as gaps between two larger vessels to detect spillage.
Applications of an Ultrasonic Level Switch
Ultrasonic level switches are sometimes described as rugged, and resistant to high temperatures, pressures, and vibrations. Ultrasonic liquid level switches are ideal for point level detection of liquids such as oils and other hydrocarbons, solvents, water, acids, caustics, condensate, and clean liquids. They offer overfill protection and are also commonly used for high or low-level detection and pump protection, fill line monitoring, seal pot level, and safety-critical high-level alarms. This makes ultrasonic liquid level switches common in industries as diverse as chemicals, petroleum, water and wastewater, pharmaceuticals, pulp and paper, power, and aerospace. Cryogenic liquids can be used with these liquid switches.
Where tuning forks, float level, or conductivity switches were previously used, ultrasonic level switches can be a cost-effective update and replacement.
How to Choose the Best Ultrasonic Level Switch
Ultrasonic liquid level switches are versatile, but when choosing the best ultrasonic liquid level switch, you may have a few questions on how to select the most appropriate option. Echotel ® Model 961/962 Ultrasonic Level Switches perform well in aerated or foamy liquids, and withstand electrical noise interference. The size of the space you have to measure could also point you towards a smaller switch to determine the presence of liquids spilling between two larger vessels, for example. The compact Echotel ® Model 940/941 Ultrasonic Level Switches are switches small enough to use in the space between tank walls for fluid leak detection. For clean liquids, Echotel ® Model 910 Ultrasonic Level Switches are an appropriate choice. Echotel ultrasonic level switches also offer dual-cast aluminum electronics housing and stainless steel transducers.
Ultrasonic level switches offer dependable solutions for detecting material, especially liquids, for your industrial applications. Please visit our TechStar page of ultrasonic switch types and solutions to decide how these products can help monitor levels of materials or blends or improve safety with your operation. Whether your liquids are dense, foamy, viscous, or light, ultrasonic liquid level switches can be used to support a wide array of functions.