CLAMP-ON FLOW METER by Seztec USA +1 (832) 899-4040
Nothing enters the pipe

Non-invasive flow meter

A non-invasive flow meter measures flow through the pipe wall. Nothing is cut, nothing is wetted, nothing obstructs the flow. No shutdown, no leak path, no pressure drop, and nothing in the stream to corrode, foul, or wear out.

One instrument, six names

People arrive at this technology from different directions and with different vocabulary. All of these describe the same thing:

Same instrument. Same physics. Same reason for existing: the line cannot come down, and nothing can touch the fluid.

What “invasive” actually costs you

Every conventional flow meter is invasive. To understand why non-invasive is worth paying attention to, look at what invasive buys you — and what it charges.

What an invasive installation costs
Invasive meterWhat it puts in your pipeWhat that costs you
Magnetic (mag) meterA spool piece with wetted electrodesShutdown, cut, flange set, new gasket, new leak path. Electrodes foul and coat.
Turbine meterA spinning rotor in the streamMoving parts in the fluid. Bearings wear. Debris destroys it.
CoriolisThe meter is the pipeExcellent accuracy, at the price of a full pipe break and significant pressure drop.
Orifice plate / DPA deliberate obstructionPermanent pressure drop, forever. You pump against it every hour of its life.
VortexA bluff body in the flowObstruction, pressure drop, and fouling in dirty service.
Clamp-on ultrasonicNothingNo shutdown. No cut. No leak path. Zero pressure drop. No wetted parts to corrode, foul, or wear.

The four situations where non-invasive is the only sane answer

1. The process cannot stop

A refinery unit. A district cooling loop. A municipal transmission main. A chilled water riser feeding a data hall. The flow you most need to measure is very often the flow you are least permitted to interrupt. There is no version of an inline meter that installs without a shutdown — so the real comparison is not “clamp-on versus mag meter.” It is clamp-on versus no measurement at all.

2. The fluid would destroy a wetted sensor

Sulfuric acid. Sodium hydroxide. Sodium hypochlorite. Ferric chloride. Solvents. A wetted meter in that stream is on a countdown — and when it fails, it does not politely stop reading. It becomes a leak path for a fluid you very much do not want on the floor. The Ultraflux Minisonic Fixed is specified for exactly this: water, acids, alkalis, chemicals, with nothing in the stream to corrode.

3. The instrument would contaminate the fluid

This one inverts the logic and it is the case people forget. In semiconductor fabs and pharmaceutical plants running de-ionized or ultrapure water, the problem is not that the fluid attacks the sensor. It is that the sensor contaminates the product. A wetted element in an ultrapure loop is a contamination source and a validation burden. Clamp-on transducers on the outside of the pipe are neither.

4. Zero pressure drop is worth real money

An orifice plate costs you head permanently. Every hour it is installed, a pump is working harder to push fluid past it, and you are paying for that in electricity. Over the life of the installation, on a large line, that is not a rounding error. A clamp-on meter obstructs nothing.

Non-invasive flow meters from Seztec USA

Portable · from $3,999

METRI Ultra ProLite Portable Flow Meter

230 g, DN10–DN2000, ±0.5% system accuracy, signal oscilloscope, integral wall thickness gauge. The value benchmark.

Specifications
Portable

Ultraflux UF801-P Portable Clamp-On Flow Meter

Data logger, automatic Reynolds detection, optional BTU kit, ±0.03 ft/s sensitivity for leak detection.

Specifications
Portable · from $8,999

Ultraflux Minisonic II P Portable Ultrasonic Flow Meter

0.5″ to 393″ from one instrument. IP68. On-screen echo diagnostics.

Specifications
Fixed

Ultraflux Minisonic Fixed Clamp-On Flow Meter

Permanent, 0.5% of reading, IP67, isolated 4–20 mA and Modbus TCP. Water, acids, alkalis, chemicals.

Specifications
Fixed

METRI IC-UPF Ultra Pro-Fixed Clamp-On Ultrasonic Flow Meter

1:2500 turndown, 16 MB timestamped datalogger, AC or DC power. Made in Britain.

Specifications
Doppler

Compu-Flow C6 Portable Doppler Ultrasonic Flow Meter

Non-invasive measurement of dirty fluid — sludge, slurry, raw wastewater.

Specifications

The one thing non-invasive cannot do

It cannot measure a pipe that is not running full. The meter multiplies velocity by the full pipe area, so on a half-full gravity line it reports roughly double the real flow — with no error flag. If your pipe is not reliably full, you need an area velocity meter. We will tell you that instead of selling you the wrong instrument.

Frequently asked questions

Is a non-invasive flow meter the same as a clamp-on flow meter?

Yes. Non-invasive, non-intrusive, non-contact, external, strap-on, and clamp-on all describe the same instrument: an ultrasonic flow meter whose transducers mount on the outside of the pipe and never touch the fluid. Different words, same technology, same buyer.

Does non-invasive mean less accurate?

Not inherently. A transit-time clamp-on meter delivers 1–2% typically and 0.5% with field calibration — competitive with most inline technologies. What differs is sensitivity to installation. An inline meter has a defined flow path built into it. A clamp-on meter depends on the pipe you put it on. Install it correctly and the accuracy is there.

Can a non-invasive meter measure through insulation or coating?

Not through insulation — remove it at the transducer locations. Thin, well-bonded paint is generally fine. Loose paint, rust scale, and mill scale must be removed: they trap air, and air stops ultrasound.

What is the cheapest non-invasive flow meter that is actually good?

The METRI Ultra ProLite at $3,999. Big-brand portables start above $10,000. The ProLite gives you ±0.5% system accuracy, a signal oscilloscope, an integral wall thickness gauge, and a 4 MB datalogger, in 230 grams. Made in Britain.

Do I need to shut down to install a non-invasive meter?

No. That is the definition of the category. The line stays live, pressurized, and flowing throughout.

Which non-invasive meter fits your line?

Send us the pipe and the fluid. If a non-invasive meter is right, we will tell you which one. If it is not, we will tell you that too.

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