SHENZHEN LONGSUN ACOUSTIC CO., LTD.

Ultrasonic level sensor is also called ultrasonic level meter using non-contact measurement level of liquid and bulk solid via ultrasonic wave, applied in the water level measurement and the size of the flow of the vessel or pipe, can also be used in tank, canals, reservoirs, rivers and lakes water level measurement, especially suitable for sewage and corrosive occasions (Figure 3-1).

Figure 3-1

Working principle of ultrasonic level sensor

Please refer to Figure 3-2 below:

Figure 3-2

From figure 3-2, the ultrasonic transducer is mounted above the detected liquids, vertical to the surface of liquid, meanwhile, the dead zone has to be considered when mounting. In previous introductions, we know, the ultrasonic level sensor is also mainly based on the principle of ultrasonic ranging, therefore, the height of level H₂ can be calculated through the following formula:

H₂=H - H_{1                       (1)}

H₁=Ct/2                             (2)

H2=H-Ct/2                 (3)

Note: 

H is a constant, C is sound wave speed, it should be C=331.5 + 0.607t_c, t_c is the surrounding temperature. t is time taking by ultrasonic pulse emitted from the transducer and echo back to the transducer when hitting the surface of liquid. 

For another example used for solid level measurement in the tank, please see below Figure 3-3:

Figure 3-3