Category
Air Velocity and Flow Transmitters
Measure air velocity and air volume flow in ducts and process air lines with Produal and Beck transmitters.
An air velocity transmitter measures air speed, or the differential pressure it creates, and outputs a continuous 4 to 20 mA or 0 to 10 V signal to a BMS or PLC. The Produal AVT reads duct velocity and temperature directly, and the DPT-Flow reads differential pressure across centrifugal fans. For building management ducts, see HVAC air velocity transmitters.
4 Products · Air Flow And Velocity Transmitter
Selection guide
Air Velocity and Flow Transmitters Guide
How an air velocity transmitter works
The Produal AVT senses air speed directly with a hot-wire style element and converts it to an analogue or digital output. The DPT-Flow instead measures differential pressure, either across a centrifugal fan's own tapping points or from a separate pitot tube or averaging probe, and calculates velocity or volume flow from that reading. Both mount permanently and output continuously.
How to choose an air velocity transmitter
- Measurement type: pick the AVT for direct duct velocity and temperature. Pick the DPT-Flow when you also need differential pressure, static pressure, or volume flow across a fan.
- Range: the AVT covers a field-selectable 0 to 2, 0 to 10 or 0 to 20 m/s, or a freely selectable range on the -D and -BT models. The DPT-Flow covers 0 to 1000, 2000, 5000 or 7000 Pa.
- Accuracy: the AVT is accurate to 0.2 m/s + 2% of reading up to 2 m/s, and 0.5 m/s + 3% up to 10 m/s. The DPT-Flow is accurate to ±1% ±2 Pa below 125 Pa.
- Output and options: both give 0 to 10 V or 4 to 20 mA. The AVT adds a display (-D), relay (-R), Modbus (-MOD) or Bluetooth (-BT) option; the DPT-Flow adds automatic zeroing (-AZ).
- Temperature: standard versions cover -20 to 50 °C (DPT-Flow) or -25 to 50 °C (AVT); the -40C DPT-Flow variant extends to -40 °C.
- Mounting: the AVT uses an adjustable duct flange in 112, 212 or 412 mm probe lengths, for round or rectangular ducts. The DPT-Flow connects to the fan's existing pressure points.
For building management and HVAC ducts specifically, see HVAC air velocity transmitters.
FAQ
Common questions
What is an air velocity transmitter used for?
It gives a continuous electrical signal proportional to air speed or flow, so a BMS or PLC can display, trend and control it. Typical jobs include duct velocity monitoring, fan performance checks and maintaining minimum outdoor air rates in HVAC systems, rather than a simple on or off alarm.
What's the difference between the Produal AVT and DPT-Flow?
The AVT senses air velocity and temperature directly in the duct. The DPT-Flow measures differential pressure, typically across a centrifugal fan's own tapping points, and converts that into flow, velocity or pressure readings. Choose the AVT for a straightforward duct reading, and the DPT-Flow for fan curve monitoring.
How accurate is the Produal AVT at low air speeds?
It's accurate to 0.2 m/s plus 2% of reading between 0.15 and 2 m/s, 0.5 m/s plus 3% between 2 and 10 m/s, and 1.0 m/s plus 3% above 10 m/s. Temperature accuracy is ±0.5 °C, so it also gives a usable duct temperature reading alongside velocity.
Can one transmitter give both fan volume flow and pressure?
Yes. The DPT-Flow measures volume flow, velocity, differential pressure and static pressure from a single unit connected across a centrifugal fan. That avoids fitting separate pressure and flow instruments where panel space or fan access is limited.
What output signals do these transmitters give?
Both the AVT and DPT-Flow give 0 to 10 V or 4 to 20 mA as standard. The AVT can add a Modbus (-MOD) option for direct BMS integration, and the DPT-Flow's automatic zeroing (-AZ) option keeps low-pressure readings accurate over time.
Are these transmitters suitable for HVAC and building management?
Yes, both work in HVAC supply, extract and process air ducts. If your project is specifically HVAC or BMS integration, our HVAC air velocity transmitters page covers the same Produal range with that application in mind, including typical duct sizes and BMS protocols.
Need help?
Can't find what you need?
Our team helps you select the right air flow and velocity transmitter products for your application. Request a quote or discuss your requirements.
Expert product guidance
Tailored selection of air flow and velocity transmitter instruments
Custom solutions
Instruments customized for your specific industrial setup
Trusted global brands
Full warranty and official documentation support