Ultrasonic Level meter and Radar level Meter Comparison

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.


Operation Pressure

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.


Operation Temperature

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


Dusty Environment

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 thin tanks.



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 ultrasonic probe.

3. Ultrasonic accuracy is not as good as radar level sensor.

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.

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