Both Ultrasonic level meter and Radar level meters are
widely used to measure liquids or solids level, and Silver Automation
Instruments would love to write this article mainly talking about the comparison
of the two level sensors.
Different Measurement Principles
The radar level transmitter is based on the dielectric
constant of the substance being measured. Ultrasonic level transmitter’s principle
is closely related with the density of the substance being measured. Therefore,
if the medium has a very low dielectric constant, the level measurement by
radar level meter is not very good.
Different transmitting waves
The radar level gauge emits electromagnetic waves, which
does not require a medium to transfer, and ultrasonic level sensor emits waves which
are sound waves, which are mechanical waves that require the medium to be
transmitted. So ultrasonic level meter cannot measure in vacuum environment;
however radar level probe can do it.
Ultrasonic waves are emitted by the vibration of
piezoelectric materials, so it is not possible to use them in high pressure or
negative pressure applications, the max pressure ultrasonic level meter can
bear is 3 Bar. Generally, they are only used in atmospheric pressure vessels.
But the radar can be used in high pressure process tank with max operation
pressure over 4 Mpa.
Ultrasonic level meter cannot measure medium with
temperature over 80°C, and Ultrasonic level probe can be affected by the
environment greatly, temperature can affect sound wave velocity. While radar
level transmitters can work for medium with max temperature 250°C
If the environment is dusty, Ultrasonic level meter cannot
have good measuring result, while Radar level meter can with High frequency can
work well in dusty environment.
Wave Remit Angle
Radars level sensor has a larger remit angle than ultrasonic
level meter waves. Non-contact radar level transmitters are not recommended for
small tanks or thin tanks. Guided wave radars can be used in small tanks or
The accuracy of the radar level meter is higher than the
ultrasonic level transmitters. For storage tank level measurement, High-accuracy
radar level meters is usually been used. As for the price, the ultrasonic level
meter is generally lower than the radar level sensor
Ultrasonic level gauge and radar level gauge
installation. Both level meters should pay attention to the tips below:
• Do not install the level probe in the feed inlet.
• Do not install the sensors near the ladder,
• A distance of 300 to 500 mm from the tank wall to
prevent echo interference.
• Choose a suitable installation method when there is
agitation and the liquid level fluctuates greatly by the agitation vibration.
Summarizing the above, we can get the following points:
1. The radar level meter has a much wider measurement
range than the ultrasonic level sensor.
2. The radar level probe has a horn type, a rod type and
a cable type, can be applied to more complicated working conditions than
3. Ultrasonic accuracy is not as good as radar level
4. Radar level transmitters are more expensive than
ultrasonic level transmitters.
5. When using radar level meter, we should consider the
dielectric constant of the medium.
6. Ultrasonic level probe should not be used in vacuum
environment, steam environment or there is foam in the liquid surface.