When it comes to liquid level sensors, there are many different styles to choose from. Standard float switches are probably the most popular and well-known options, but there are also more sophisticated units like hydrostatic pressure sensors, optical liquid level sensors, and more. Ultrasonic liquid level sensors, which use pulses of ultrasonic sound to calculate liquid levels, are versatile and extremely reliable. But like any level sensing technology, they have pros and cons.
If you’re wondering if ultrasonic liquid level sensors are right for your application, take a look at some of their disadvantages below. If any are relevant to you, it’s probably best to try a different sensor technology.
Disadvantages of Using Ultrasonic Liquid Level Sensors
Not Appropriate for Use with Every Liquid Medium
Ultrasonic level sensors work by emitting pulses of ultrasonic sound, which then bounce back to the sensor unit to establish where the liquid line is located within a tank or vessel. With some liquid media, however, these ultrasonic waves are absorbed rather than reflected. If you’re thinking about using an ultrasonic level sensor, be sure that your liquid medium reflects ultrasonic sound rather than absorbing it.
May Not Work with Agitated Liquids
Agitated liquids, turbulent liquids, foaming, sloshing, and other activity can hamper the performance of ultrasonic sensors. In applications where liquid agitation is common, ultrasonic sensors may, therefore, be a poor choice. This may not necessarily be the case, however: the integration of a so-called still pipe can allow for ultrasonic sensor use with some agitated liquids.
No Side or Bottom Mounting
Since ultrasonic sensors work by emitting sound waves directly at the liquid surface, top-mounting is necessary. This means that applications or facilities that require bottom or side-mounted sensors are not well-suited for ultrasonic sensors.
Alternatives to Ultrasonic Liquid Level Sensors
If any of these disadvantages are a deal breaker for your application, there are still plenty of alternatives.
Submersible Pressure Sensors
Like ultrasonic sensors, submersible pressure sensors offer continuous liquid level measurement by measuring hydrostatic pressure from the bottom of a tank or vessel. These devices do not need to be mounted to the tank, and are instead attached to a long through the line. This offers a great deal more versatility than ultrasonic sensors.
Optical Liquid Level Sensors
For point-level detection with no moving parts, optical level sensors are ideal. They use refracted infrared light beams to detect the presence or absence of the liquid media being measured.