Accurate Flow Direction Detection
The calorimetric measuring principle detects even the smallest changes in flow direction – below 0.1 m/s. Ideal for closed-loop compressed air and gas systems.
CS Instruments – VA 409
The VA 409 thermal directional flow meter enables fast, reliable, and maintenance-free detection of compressed air and gas flow direction in closed ring pipeline systems.
| Measuring Principle: Calorimetric |
| Direction Detection: < 0.1 m/s (at 20 °C, 1000 mbar) |
| Measured Medium: Compressed air, gases |
| Operating Pressure: up to 16 bar (232 psi) |
| Power Supply: 24 V DC |
| Outputs: 2 × potential-free contacts (NC / NO) |
| Visual Indication: 2 LEDs for flow direction |
| Protection Rating: IP54 |
| Process Connection: G 1/2″ |
| Measuring Principle: Calorimetric |
| Direction Detection: < 0.1 m/s (at 20 °C, 1000 mbar) |
| Measured Medium: Compressed air, gases |
| Operating Pressure: up to 16 bar (232 psi) |
| Power Supply: 24 V DC |
| Outputs: 2 × potential-free contacts (NC / NO) |
| Visual Indication: 2 LEDs for flow direction |
| Protection Rating: IP54 |
| Process Connection: G 1/2″ |
- VA 409 – Directional Flow MeterThermal directional flow meter for compressed air and gases, designed to detect flow direction in closed-loop pipelines. The calorimetric measuring principle detects even very small changes in flow direction (< 0.1 m/s). Equipped with two LED flow direction indicators and two potential-free contacts (NC).
| Parameter | VA 409 |
|---|---|
| Response Range (Direction Detection) [m/s] | < 0.1 (at 20 °C and 1000 mbar) |
| Measuring Principle | Calorimetric measurement |
| Sensor | Pt 30 / Pt 700 / Pt 330 |
| Measured Medium | Air, gases |
| Operating Temperature (Probe) [°C] | 0 … +50 |
| Operating Temperature (Housing) [°C] | -20 … +70 |
| Operating Pressure | up to 16 bar (232 psi) |
| Power Supply | 24 VDC, 40 mA |
| Current Consumption (max.) [mA] | 80 (at 24 VDC) |
| Protection Rating | IP54 |
| EMC | according to DIN EN 61326 |
| Connection | 2 × M12, 5-pin (Connector A and Connector B) |
| Potential-Free Contacts | 2 × U max. 60 VDC, I max. 0.5 A (standard: normally closed / NC; optional: NO) |
| Housing | Polycarbonate |
| Probe Material | Stainless steel 1.4301 |
| Probe Dimensions | Length 629 mm; Ø 10 mm (0.39″); safety ring Ø 11.5 mm (0.45″); longer probes available on request |
| Mounting Thread | G 1/2″ |
| Housing Diameter | 2.5″ |
| Direction Indication | 2 LEDs |
Why Choose the VA 409?
No Mechanical Moving Parts
Unlike conventional paddle switches, the VA 409 operates without mechanical movement, eliminating wear while providing greater reliability and a longer service life.
Fast and Reliable Response
The sensor reacts virtually in real time and quickly detects changes in flow direction, even at very low flow velocities and under unstable conditions.
Easy Integration into Monitoring Systems
Flow direction is transmitted via a potential-free contact (NC or optional NO) to VA 5xx flow meters or directly to a Building Management System (BMS).
Clear Visual Indication
Two LED indicators on the housing provide immediate and unambiguous visual indication of flow direction directly at the installation point.
Installation Without System Shutdown
The VA 409 can be installed under pressure without requiring system shutdown or pipeline depressurization.
Ideal for Ring Pipelines
In combination with two VA 5xx sensors, the device enables precise measurement of inlet and outlet flow in closed-loop systems, which is essential for energy optimization.
Energy
Energy MonitoringReliable monitoring of air and gas flow direction to support energy management and optimization of industrial systems.
Compressor Stations
Ring-Main SystemsMonitoring flow direction in compressor stations and closed-loop compressed air systems for efficient air distribution management.
Chemical Industry
Process GasesReliable flow direction detection of technical gases to ensure stable and safe chemical processes.
Food Industry (N₂ / CO₂)
Inert GasesMonitoring the flow direction of nitrogen and CO₂ in packaging, cooling, and protective atmosphere applications to ensure stable process conditions.
Automotive Industry
Process AirMonitoring air and gas flow direction in manufacturing, assembly, and painting processes to improve system reliability.
Aerospace Industry
Critical ProcessesPrecise flow direction detection for monitoring gas systems in demanding and safety-critical applications.
Metallurgy and Welding
Shielding GasesMonitoring the flow direction of shielding and process gases to ensure stable welding and metallurgical operations.
Natural Gas and Steam
Industrial UtilitiesMonitoring the flow direction of industrial gases and process media for energy and process applications.
Measuring devices
Tell us what you measure and we will propose the right instrument.
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.
Proposal of the right instrument type and measuring range
Measurement reports, trends, and interpretation of results
Supply, installation, calibration, and service
Where to find us
DirectionsPod lipami 4 · 1370 Logatec, Slovenija
Flow Meters
Choose the right flow meter for compressed air, technical gases, steam, or other industrial media. Our portfolio includes thermal, differential pressure, Venturi, and vortex flow meters for a wide range of applications.
VA 526
New deviceNew compact inline flow sensor with Bluetooth, IO-Link and PoE, plus optional pressure and dew point measurement.
Learn more→
CMM 500
Venturi Flow MeterHigh-accuracy Venturi flow meter, ideal for compressor monitoring and compressed air consumption billing.
Learn more→
VA 500
Thermal Flow MeterThermal mass flow meter for compressed air and gases with RS-485, 4–20 mA, and pulse outputs.
Learn more→
VA 520
Inline Thermal Flow MeterThermal flow meter with integrated measuring section for distribution systems and consumption monitoring.
Learn more→
VA 550
Industrial Thermal Flow MeterRobust thermal flow meter for demanding industrial applications, also available with ATEX and DVGW approvals.
Learn more→
VA 570
Flow Consumption MeterThermal flow meter with a compact measuring section, ideal for consumption monitoring and cost allocation.
Learn more→
VA 521
Compact Inline Flow MeterCompact inline flow meter for compressed air and gases, suitable for smaller pipelines and machinery.
Learn more→
VA 525
Compact Inline Flow MeterCompact inline flow meter for compressed air or nitrogen in specialized applications.
Learn more→
VD 500
Differential Pressure Flow MeterDifferential pressure flow meter for wet compressed air or gases with a wide measuring range.
Learn more→
VD 520
Inline Differential Flow MeterInline differential pressure flow meter with an integrated flow conditioner.
Learn more→
VD 550
Heavy-Duty Differential Flow MeterRobust differential pressure flow meter for wet air or gases in demanding industrial environments.
Learn more→
VD 570
Inline Differential Flow MeterInline differential pressure flow meter for larger pipelines and industrial processes.
Learn more→
VU 570
Vortex Ultrasonic Flow MeterVortex ultrasonic flow meter for technical and mixed gases, offering high measurement accuracy.
Learn more→
VX 570
Vortex Flow MeterVortex flow meter for gases, steam, and liquids with integrated pressure and temperature compensation.
Learn more→