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Air Flow Sensor – Geonica

Open Path Ultrasonic Air Flow Monitoring for Tunnels, Ventilation & Safety Systems

The GEO-CROSSFLOW Air Flow Sensor by Geonica is a high-performance open path ultrasonic air flow monitor specifically designed for measuring air speed and airflow direction in road tunnels, rail tunnels, and other enclosed ventilation environments. It is ideal for multi-lane and bi-directional tunnels, where accurate airflow monitoring is critical for tunnel ventilation control, smoke management, energy efficiency, and operational safety. The system consists of a pair of ultrasonic transceivers mounted on opposite sides of the tunnel bore. Both transceivers transmit and receive ultrasonic pulses, measuring the difference in sound wave transit time in each direction. This precise transit-time difference is used to determine airflow speed and direction across the tunnel, helping optimize ventilation fans and emergency smoke extraction systems. The sensor is specifically designed for harsh tunnel environments with IP67 protection, stainless steel construction, and low-maintenance “fit and forget” operation.

Key Features:

  • 🌬️ Accurate Air Speed & Direction Measurement

    Uses reliable ultrasonic transit time technology to continuously measure tunnel airflow speed and direction with high accuracy, supporting safe and efficient ventilation control.

  • 🚇 Designed Specifically for Tunnels

    Built for use in multi-lane and bi-directional tunnels, where airflow patterns are complex and precise monitoring is essential for ventilation and smoke extraction systems

Key Features:

  • 📡 Multiple SCADA / PLC Interface Options

    Supports industry-standard outputs including 0/2/4–20 mA analog outputs, alarm relay contacts, and serial communication protocols for easy integration with tunnel automation systems and control rooms

  • 🛡️ No Moving Parts – Low Maintenance

    With no moving or wear-prone components, the GEO-CROSSFLOW offers highly reliable long-term performance with minimal service requirements and automatic self-diagnostics

Applications:

  • 🚇 Road & Railway Tunnels

    Used for monitoring airflow direction and ventilation efficiency in urban tunnels, highways, and metro systems.

  • 🔥 Tunnel Smoke Management

    Supports emergency smoke extraction systems by detecting airflow behavior during fire and low-visibility incidents.

  • ⚡ Energy-Efficient Ventilation Control

    Helps optimize fan operation and reduce tunnel energy consumption through real-time airflow measurement.

  • 🏭 Industrial Ventilation Systems

    Suitable for large enclosed airflow monitoring applications where reliable directional air measurement is required.

Why Choose This Solution?

The GEO-CROSSFLOW delivers dependable airflow monitoring with rugged tunnel-ready performance and minimal maintenance.

Precise Cross-Bore Air Measurement

Provides accurate full-tunnel airflow monitoring instead of point-based local measurements.

Simple Integration with Existing Systems

Works easily with PLCs, SCADA systems, and tunnel control platforms through flexible interface options.

Reduced Maintenance Costs

No moving parts and automatic diagnostics minimize servicing and operational downtime.

Built for Harsh Tunnel Environments

IP67-rated enclosure and stainless steel construction ensure reliable long-term operation even under aggressive tunnel cleaning cycles.

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