We're looking for a sensor/transmitter to measure our liquid nitrogen level, but the same vessel will receive liquefied natural gas too. The tank is approximately 3 meters tall. Ideally, we'd like to use a non-contact method.
Expert’s answer : Liquid nitrogen level measurement
Challenge accepted! Actually, we have two here, the low temperature and the low dielectric constant (DC) of the liquid nitrogen. This scenario limits the number of principles you can use. But don’t despair! We have some options.
You could use one of two common solutions: a differential pressure (DP) transmitter or a guided radar device. However, both need particular materials because of the low temperature. If you go with a DP device, then you have probes for cryogenic applications and fluids for low temperatures. If you choose the guided radar, then you must have the right seal.
But if neither of these solutions appeal to you, maybe you’ll like one of the new free space radars. Working at 80 gigahertz, they can measure low DCs in smaller vessels. Furthermore, depending on the application, you might find a high-accuracy radar for the natural gas. You should make sure it has the appropriate antenna, though, like a still-pipe antenna.
So you could go old school DP transmitter with the proper liquid or a guided radar with an appropriate cryogenic seal. Or you could take a new route with a free space radar, if you have the right DC values, or a high-accuracy radar with the proper antenna. No matter what you use, you’ll need to adjust from standard specs to handle your products.
This list of articles can tell you more about the principles mentioned here:
Do you know when you should apply a guided wave radar rather than a non-contact radar? If you don’t, then keep reading!
Time of flight (ToF) refers to the time it takes for things such as acoustic or electromagnetic waves to travel through a medium from Point A to Point B and return.For more, click the article.