Flow measurement
If you don't measure consumption, you don't know what compressed air costs you. CS Instruments flow meters measure standard volume flow in m³/h and total consumption – even the smallest leaks, per line and department.
Why measure flow
Electricity accounts for 70–80 % of compressed air costs. Flow measurement shows the actual consumption per department, the cost per m³, consumption while production is idle (leaks) and whether the compressors are sized correctly.
Thermal meters measure mass flow directly, so they need no additional pressure and temperature compensation, have no moving parts and cause almost no pressure drop. For wet air directly downstream of the compressor, differential pressure meters are the right choice.
New deviceNew from CS Instruments
Flow, consumption and temperature – optionally pressure and dew point – in one compact sensor you set up from your phone.
CS Instruments models
Insertion probes for existing pipes, inline meters with a measuring section for the highest accuracy, and meters for wet air, steam and mixed gases.
Compact inline · new
New compact flow sensor for air and gases: Bluetooth and CS SensorApp, IO-Link, PoE, optional pressure and dew point.
Insertion probe
Thermal probe for air and gas flow and consumption, installed under pressure in pipes from 1/2″.
Robust probe, ATEX
Thermal probe in a robust housing for pipes from 3/4″ to over DN 1000, also for Ex areas.
Probe for wet air
Differential pressure flow meter for wet air directly downstream of the compressor, up to 180 °C.
Probe for wet air
Robust differential pressure probe for wet air and gases up to 100 bar.
Direction meter
Thermal flow direction meter for compressed air ring mains.
Reference meter
Compressor Master Meter with Venturi tube for compressor acceptance tests and billing.
Inline measuring section
Thermal meter with measuring section and flange or thread, also for Ex areas and 180 °C.
Inline measuring section
Compact inline meter with integrated measuring section for accurate consumption measurement.
Compact inline
Compact inline sensor for air and gases from DN 15 to DN 50.
Compact inline
Compact thermal flow sensor for air and nitrogen with G 1/4″ to G 2″ thread connection.
Inline, differential pressure
Inline meter with averaging pitot tube for wet compressed air.
Inline, differential pressure
Robust inline differential pressure meter for wet air and gases.
Vortex + ultrasonic
Flow meter for technical and mixed gases (non-condensing), up to 40 bar.
Vortex
Vortex meter for steam, gases and liquids up to 350 °C and 63 bar.
Comparison
| Model | Version | Measuring principle | Accuracy | Pressure | Temperature |
|---|---|---|---|---|---|
| VA 526 | Inline | Thermal (calorimetric) | ± 1.5 % m.v. ± 0.3 % f.s. | 16 bar (40 bar) | -20…+80 °C |
| VA 500 | Stationary | Thermal (calorimetric) | ± 1.5 % m.v. ± 0.3 % f.s. | -1…50 bar | -30…+110 °C |
| VA 550 | Stationary | Thermal (calorimetric) | ± 1.5 % m.v. ± 0.3 % f.s. | 50 bar (100 bar) | -20…+180 °C |
| VD 500 | Stationary | Differential pressure | ± 1.5 % m.v. | -1…30 bar | -30…+180 °C |
| VD 550 | Stationary | Differential pressure | ± 1.5 % m.v. | -1…100 bar | -30…+180 °C |
| VA 409 | Stationary | Thermal (calorimetric) | – | 16 bar | – |
| CMM 500 | Inline | Venturi (ISO 5167-3) | ± 0.5 % (0.2 Qmax…Qmax) | 16 bar (30 / 100 bar) | – |
| VA 570 | Inline | Thermal (calorimetric) | ± 1.5 % m.v. ± 0.3 % f.s. | 16 bar (40 bar) | -20…+180 °C |
| VA 520 | Inline | Thermal (calorimetric) | ± 1.5 % m.v. ± 0.3 % f.s. | -1…16 bar (PN 40) | -30…+80 °C |
| VA 521 | Inline | Thermal (calorimetric) | ± 1.5 % m.v. ± 0.3 % f.s. | 16 bar (40 bar) | -30…+80 °C |
| VA 525 | Inline | Thermal (calorimetric) | ± 1.5 % m.v. ± 0.3 % f.s. | 16 bar | -20…+60 °C |
| VD 520 | Inline | Differential pressure | ± 1.5 % m.v. | -1…30 bar | -30…+80 °C |
| VD 570 | Inline | Differential pressure | ± 1.5 % m.v. | -1…30 bar | -30…+80 °C |
| VU 570 | Inline | Vortex + ultrasonic | ± 1.5 % m.v. | 40 bar | -40…+100 °C |
| VX 570 | Inline | Vortex | ± 1 % m.v. | 63 bar | -40…+350 °C |
Measuring principles
The choice of principle depends on the medium, moisture, temperature and required accuracy.
For dry compressed air and gases downstream of the dryer. Measures mass flow directly, wide turndown, no moving parts.
For wet, undried air directly downstream of the compressor and high temperatures up to 180 °C. Shorter inlet sections thanks to the averaging pitot tube.
For technical and mixed gases, steam and liquids. VX 570 up to 350 °C and 63 bar.
Venturi tube to ISO 5167-3 with ± 0.5 % accuracy for compressor acceptance tests and consumption billing.
How to choose
Up to DN 80 inline meters with a measuring section are suitable, for larger pipes insertion probes.
You need to know the minimum and maximum flow – including night-time consumption, when we measure leaks.
Dry air: thermal meter. Wet air after the compressor: differential pressure. Steam and mixed gases: vortex.
4…20 mA, pulse or Modbus to the control system, or recording in a DS 500 with energy analysis.
FAQ
The key factors are pipe diameter, expected minimum and maximum flow, operating pressure, type of medium and moisture. For dry air we recommend a thermal meter, for wet air directly after the compressor a differential pressure meter.
Yes. For an accurate measurement the meter needs a settled flow, so straight pipe sections are planned before and after the measuring point. Inline meters have a built-in measuring section, which ensures repeatable accuracy.
When production is idle (weekend, holiday, night shift), the compressors only supply air for leaks. The flow meter shows this base flow and the data logger calculates the cost of leaks in €.
Yes, thermal meters measure air, nitrogen, oxygen, argon, helium, CO₂ and vacuum. The meter must be set to the correct gas, otherwise the measurement is not accurate.
Insertion probes (VA 500, VA 550, VD 500, VD 550) are installed under pressure via a ball valve. For inline meters a pipe section must be replaced with the measuring section.
Related measurements
Fill in a short form and we will prepare a proposal for measurement equipment and implementation based on the medium, measuring range, and measurement objective.
