Rainwater Pipe Network Doppler Flowmeter / Sewer Flowmeter [Dayu Electronics]
Urban manhole liquid level monitoring, battery-powered, collecting data every 15 minutes, achieving a 1-year service life.
Water level monitoring uses an ultrasonic level meter. Its working principle is that the transducer (probe) emits high-frequency ultrasonic pulses that are reflected back when they encounter 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 of the ultrasonic pulse is proportional to the distance from the transducer to the surface of the measured medium. The relationship between this distance value S, the sound speed C, and the transmission time T can be expressed by the formula: S = C × T / 2.
In underground pipe network stormwater and sewage systems, due to the thick accumulation of urban sewage sludge, if a submersible level transmitter is used, the water level pressure sensor will quickly be buried by the sludge. The submersible level transmitter is a contact-type measurement; considering later maintenance and equipment lifespan, an ultrasonic level meter is adopted instead.
For water level monitoring in inspection wells, a wall-mounted ultrasonic level meter is used. It can be installed on the manhole cover of sewage pipes and combined stormwater/sewage pipes. For reservoir water level monitoring, it is fixed to the pool wall.
According to the working principle of the monitoring equipment, when the transducer emits ultrasonic pulses, it has a certain emission angle. From the lower edge of the transducer to the surface of the measured medium, there must be no obstacles within the area radiated by the emitted ultrasonic beam. Therefore, during installation, other obstacles should be avoided as much as possible, such as ladders, limit switches, heating equipment, and supports.
When installing the instrument, attention should also be paid to the following: the highest water level must not enter the measurement blind zone; the instrument must maintain a certain distance from the tank wall; the installation of the instrument should make the transducer's emission direction as perpendicular to the liquid surface as possible.