0° Elevation Flow Meter: Field Measurement Solution for 50mm Water Level in Sandy Sewage Pipes [Dayu Electronics]
Ultrasonic Doppler Flow Meter is not only used for measuring water level, flow velocity, and flow rate in rivers, irrigation districts, and culverts, but also for measuring full-pipe or partial-fill flow in sewage pipes. It is suitable for pipes with a diameter of DN200 or above, requiring only a minimum water level of 5cm.
Our self-produced low-water-level compact flow sensor has a 0° elevation angle, meaning the sensor transmits signals horizontally. The sensor itself is approximately 38mm in height, recommended for use in water levels above 50mm, with at least 2m of straight pipe section in front of the sensor, and free of any obstacles that could cause turbulence or block acoustic wave transmission (the channel should ideally follow the '10 before, 5 after' principle; for a DN200 pipe, maintain 2m straight section in front and 1m straight section behind the sensor).
Cross-section view of internal installation in a sewage pipe
For battery-powered accessory products, the antenna used is a waterproof sewage antenna; if no waterproofing is required, it can be replaced with a standard antenna. When installing the antenna, if the manhole cover is concrete, simply position the antenna close to the cover. If the manhole cover is metal, it is recommended to dig a trench near the cover and embed the antenna in the trench.
Field case:
The customer needed to measure the flow in a DN400 sewage pipe with a water level of approximately 100–200mm, and the sewage contained some sediment. The measurement point was required to be downstream of a valve, but there was no available installation space there, so a small Doppler flow meter was installed at the upstream outlet. Based on communication with the customer, external power was available on-site, and data did not need to be transmitted remotely—only local display was required. We recommended the compact ultrasonic Doppler flow meter with a 0° elevation sensor for installation.
Installation suggestion: At the outlet, use an L-shaped stainless steel bracket to secure the Doppler flow sensor. Position the sensor's transmitting face against the water flow. Protect the cable at the sensor's tail with a flexible conduit and route it into a stainless steel riser for protection. For externally powered environments, route the cable to the equipment enclosure and keep the air tube dry.