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Pitot tubes – standard or built for your duct
- Standard lengths from 630 to 3,500 mm, both S-type and L-type, each with its own article number.
- Built to order: length 300–4,000 mm, stainless steel or Inconel, a sliding brass fitting (standard 1¼ inch), hose nipples or Swagelok valves.
- Extendable pitot tubes in three or four sections, for when the duct is large and the space small.
- Homogeneity probe: an option with an extra tube for gas analysis and a type K thermocouple. You then measure velocity, oxygen concentration and temperature at the same points when the measurement plane is checked according to EN 15259.
- Mounts with an adjustable adapter for sampling ports of ½, ¾, 1 and 1¼ inch.
Standard range
Each standard length is an article of its own. We build other lengths, materials and fittings to order.
| Type | Lengths, mm | Dimensions |
|---|---|---|
| L-type pitot tube | 630, 800, 1,000, 1,250, 1,400, 1,600, 1,800, 2,000, 2,500, 3,000, 3,500 | Body 8–20 mm depending on length, tube 8–10 mm |
| S-type pitot tube | 630, 800, 1,000, 1,250, 1,400, 1,600, 1,800, 2,000, 2,500, 3,000, 3,500 | Head tubes 10/8 mm, body 22/20 mm |
FlowGuard 100 – continuous flow measurement
- Fixed or portable. A compact system for flow measurement in stacks and for process monitoring, for wall mounting or with a handle for portable use, together with an S-type or L-type pitot tube.
- 5–35 m/s. Optimised for gas velocities in that range, with MicaFlex manometers from Micatrone: dynamic pressure 0–1,000 Pa and static pressure ±5 kPa.
- Purged automatically. A programmable purge with compressed air (at most 8 bar) keeps the pressure lines clean, so the system copes with gas containing particles or water droplets.
- Output signals 0–10 V or 4–20 mA for dynamic and static pressure.
- Compact: 380 × 380 × 210 mm, 18 kg. Article number GF22-101.
Calibrated on delivery
METLAB is accredited by Swedac (the Swedish accreditation body) for the calibration of gas velocity and gas flow. Pitot tubes are calibrated at 5, 10, 15, 20, 25, 30 and 35 m/s and delivered with an accredited calibration certificate, and the manometers in FlowGuard 100 can be calibrated before delivery. If you already have pitot tubes, including from other manufacturers, you can send them in for calibration.
Example: pitot tubes for the chemical industry
A chemical plant needed accurate flow monitoring in more than 20 process lines, with tight spaces and corrosive gas. We built S-type pitot tubes with a compact geometry for the tight spots, sliding brass fittings for secure mounting, Inconel for chemical resistance and Swagelok valves for safe maintenance. We calibrated both the pitot tubes and the manometers under accreditation.
Calibration and measurement
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Service · accreditedPitot tube calibration
Send in your pitot tubes and have them calibrated at 5–35 m/s with a certificate.
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Service · accreditedFlow measurement on site
We measure gas flow according to EN ISO 16911-1 as part of the emission measurement.
Frequently asked questions about pitot tubes
What is the difference between S-type and L-type pitot tubes?
The L-type pitot tube (Prandtl tube) has a coefficient close to 1 and is very accurate, but its small openings can clog in dusty or wet gas. The S-type pitot tube has larger openings and copes better with dust and moisture, but needs to be calibrated to obtain its coefficient.
What length do I need?
The pitot tube must reach across the whole measurement plane from the sampling port: at least the duct's inner diameter plus the length of the port's stub pipe, and a little more for the handle and fittings. Tell us the duct's dimensions and we will work it out.
Can you calibrate pitot tubes from other manufacturers?
Yes. We also calibrate other manufacturers' pitot tubes and other gas flow equipment, for example gas meters.
What is needed to install FlowGuard 100?
A pitot tube in the duct, compressed air for the purge (at most 8 bar), power and room for wall mounting. The output signals are connected to the plant's control system.