A portable clamp-on Doppler flow meter for the fluids transit-time cannot see: sludge, slurry, raw wastewater and aerated streams. Pipe ID 0.5″ to 500″.
SKU C6PF · FROM $6,990
Your fluid has solids or bubbles in it. If it is clean, buy transit-time — Doppler will give you nothing.
A transit-time meter fires a pulse across the fluid and times it. It needs the fluid acoustically clear. Fill it with solids or bubbles and the pulse scatters — the meter loses signal and drops out.
A Doppler meter measures the frequency shift of sound bouncing off particles carried in the flow. It needs reflectors. In clean water there is nothing to reflect off and it reads nothing at all.
They fail at exactly the job the other one does. This is physics, not a product tier. Full comparison →
Doppler has a set of insensitivities that are genuinely useful on a dirty line. The C6 is unaffected by changes in temperature, viscosity, specific gravity, or the speed of sound in the liquid. The liquid does not need to be electrically conductive — which is where a magnetic flow meter would stop.
Think about what that rules out. A sludge line whose solids loading changes hour to hour changes its density, its viscosity and its speed of sound. A transit-time meter has to cope with all of that. The Doppler meter is measuring a frequency shift and simply does not care.
This is the specification that makes the C6 work where other meters cannot go. The transducer belongs on the pipe — in the wet well, at the bottom of the shaft, in the pit. The display belongs somewhere a human can safely stand. Five thousand feet of separation is a lot of freedom about where those two places are. The transducer is potted IP68 and submersible to 200 ft; it is built to be underwater and stay there.
1%, and the datasheet says “a function of flow profile.” Believe that. Doppler measures the velocity of the reflectors, and reflectors are not evenly distributed in a pipe carrying slurry — heavier solids concentrate low, bubbles rise. What the meter sees depends on where in the profile its beam is looking.
Doppler is excellent for trending, control and relative change. It is not the instrument for custody transfer. If someone is being billed off the number, we will steer you elsewhere and tell you why. A NIST certificate of calibration is available.
| Measurement principle | Ultrasonic Doppler, clamp-on |
|---|---|
| Pipe size range | 0.5 in to 500 in ID (12 mm to 12,000 mm) |
| Accuracy | ±1% (a function of flow profile); linearity ±0.5%, repeatability ±0.1% |
| Velocity range | 0 to 50 ft/s (15 m/s), resolution 0.1 ft/s |
| Fluids | Dirty liquids — sludge, slurry, raw wastewater, aerated streams. Requires suspended solids or entrained gas. |
| Transducer temperature | −30 to +90 °C; to +250 °C with special fittings |
| Wall thickness gauge | Not applicable |
| Data logging | 12-digit totalizer with memory backup |
| Energy / BTU | No |
| Battery life | AC or DC, solar or battery powered |
| Ingress protection | Transducer IP68 submersible to 200 ft; display NEMA 4X / IP64 |
| Instrument weight | 8 lb (3.6 kg) |
| Outputs | 4–20 mA, pulse 0–12 V, RS232, hi/low alarms |
| Origin | United States |
| Price | From $6,990 (published) |
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.
Use Doppler when the fluid is dirty. The Compu-Flow C6 Portable needs suspended solids or entrained gas to reflect from, which makes it the right instrument for sludge, slurry, raw wastewater and aerated streams — exactly the fluids where transit-time instruments lose acoustic lock.
The reverse is the trap: point a Doppler meter at clean, filtered water and there is nothing to reflect from. On a plant with both clean and dirty lines you need two instruments, or a hybrid like the Badger Dynasonics DXN-5P.
The Compu-Flow C6 Portable specifies ±1% accuracy as a function of flow profile, with ±0.5% linearity and ±0.1% repeatability. Doppler accuracy depends on the distribution of reflectors in the fluid, so it is more profile-sensitive than transit-time.
The C6 is insensitive to changes in temperature, viscosity, specific gravity and speed of sound, and the liquid does not need to be conductive — which is why it works where magnetic flow meters cannot.
Yes. The Compu-Flow C6 transducer is potted, non-metallic and rated IP68, submersible to 200 ft. Transducer temperature range is −70 °F to +185 °F, with a 500 °F heat-sink option for hot lines.
The display enclosure is separately rated NEMA 4X / IP64 and is not submersible. Standard cable is 25 ft, extendable to 5,000 ft, so the electronics can sit well clear of a flooded chamber.
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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