A submerged area-velocity flow meter for pipes that are not running full and for open channels — raw sewage, industrial effluent and storm water. One control unit monitors up to 16 sensors.
SKU ORAKEL-AV
Your pipe is not running full, or it is an open channel. A clamp-on meter cannot help you here.
The ORAKEL sensor goes in the channel, not on the outside of the pipe. It is in this catalog because it solves the one problem clamp-on cannot: a pipe that is not running full.
A transit-time clamp-on meter computes volumetric flow as velocity × cross-sectional area, and it takes the area from the pipe dimensions you entered at setup. That arithmetic silently assumes the pipe is completely full of liquid.
Run that meter on a gravity sewer that is half full and two things go wrong. The acoustic path may pass through air, and the meter loses signal entirely. Or — worse — the path stays submerged, the meter reports a velocity, multiplies it by the full pipe area, and hands you a flow rate that is roughly double reality. It looks completely plausible. Nothing on the display suggests a problem.
That is not an instrument defect. It is the instrument doing exactly what it was told, on a pipe it was never designed for.
It measures both variables, continuously. A Doppler ultrasonic sensor reads velocity, reflecting off the solids in the flow (of which raw sewage has no shortage). A hydrostatic pressure sensor reads how deep the liquid actually is, right now. Combine depth with the known geometry and you get the actual wetted area at this instant. Multiply by measured velocity and you have real volumetric flow, whether the pipe is 15% full or 95% full.
Anything you put in a sewer will eventually collect rag. That is not pessimism, it is the operating environment. The ORAKEL sensor is velocity-profiled to shed material rather than snag it. This is the honest trade of area-velocity: you accept a sensor in the flow — and a maintenance interval — because the alternative is not measuring the flow at all.
The control unit takes 2 sensors as standard and expands to 16. For inflow-and-infiltration studies, storm overflow monitoring and catchment modelling, instrumenting many points from one head end is the difference between a project and a purchase order.
| Meter type | Area Velocity Flow Meter (AVFM) — submerged sensor, NOT clamp-on |
|---|---|
| Application | Open channel and partially filled pipe flow measurement |
| Sensors | Doppler velocity sensor, hydrostatic depth sensor, integrated temperature sensor |
| Sensor channels | 2 sensors as standard, expandable to 16 |
| Flow velocity range | 0.03 m/s to 4.00 m/s (resolution 1 mm/s) |
| Velocity linearity | ±1% |
| Velocity accuracy | ±2.5% FS |
| Depth range | 0.0 m to 6.0 m |
| Depth linearity | 0.1% BSL |
| Depth accuracy | ±0.2% FS |
| Outputs | 4–20 mA and Modbus |
| Protection | IP68 sensor module |
| Operating temperature | −20 °C to +60 °C |
| Approvals | CE approved |
| Fouling | Velocity-profiled sensor reduces fouling and ragging risk |
Specifications transcribed from the manufacturer datasheet and subject to change. Confirm against the controlling document before specifying — Seztec will send it to you on request.
This instrument is specified into the following industries. Each page covers the specific measurement problems, the fluids involved, and what usually goes wrong.
Send us pipe size, pipe material, wall thickness, lining, fluid, and how much straight run you have. A Seztec application engineer will confirm the fit — or tell you it is the wrong instrument, which happens and which we would rather say before you buy.
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