How Does an Ultrasonic Water Level Meter Accurately Measure Urban Groundwater Levels? [Dayu Electronics]
Urban manhole liquid level monitoring is powered by batteries, with adjustable data collection intervals and upload frequencies. The water level is monitored using an ultrasonic water level meter, whose working principle involves a transducer (probe) emitting high-frequency ultrasonic pulses that are reflected back upon encountering the surface of the measured medium. Part of the reflected echo is received by the same transducer and converted into an electrical signal. The ultrasonic pulse propagates at the speed of sound, and the time interval from transmission to reception is proportional to the distance between the transducer and the surface of the measured medium. This distance S is related to the speed of sound C and the transmission time T by the formula: S = CxT/2.
In underground pipe networks for stormwater and sewage, due to the thick accumulation of urban sewage sediment, if a submersible water level meter is used, the water level pressure sensor will quickly become buried by sediment. The submersible water level meter is a contact-type measurement device. Considering long-term maintenance and equipment lifespan, an ultrasonic water level meter is therefore preferred.
For water level monitoring in inspection wells, a wall-mounted ultrasonic water level meter can be installed on the covers of inspection wells in sewage pipes and combined storm-sewage pipes. For reservoir water level monitoring, it can be fixed to the pool wall.
According to the working principle of the monitoring device, the transducer emits ultrasonic pulses with a certain emission opening angle. In the region from the lower edge of the transducer to the surface of the measured medium, within the area radiated by the emitted ultrasonic beam, there must be no obstacles. Therefore, during installation, other obstacles should be avoided as much as possible, such as ladders, limit switches, heating equipment, brackets, etc.
When installing the instrument, the following points should also be noted: the maximum water level must not enter the measurement blind zone; the instrument must maintain a certain distance from the tank wall; the instrument should be installed so that the transducer's emission direction is perpendicular to the liquid surface.