• Designed specifically for tunnels
• Reliable ultrasonic transit time measurement
• No moving parts or wear items, low maintenance
• Range of on-board outputs, the control unit (TSCU) is optional.
• Separate alignment brackets with latched sensor attachment
• High quality plug and socket connectors for external connections

GEO-CROSSFLOW is a cross bore air flow monitor designed to measure air speed and direction in multi-lane and bi-directional tunnels. The monitor consists of a pair of transceivers which are mounted and aligned on either side of the bore. The transceivers both emit ultrasonic pulses and measure the sound waves time in flight in each direction. The difference between these flight times is used to determine the flow of air within the tunnel. This can then be used as part of the tunnel’s ventilation and energy management system.

GEO-CROSSFLOW is a self-contained intelligent analyser with on-board industry standard SCADA/PLC interface options, such as 0/2/4-20 mA outputs, alarm relay contacts and a choice of serial communications protocols. As such the GEO-CROSSFLOW has no need for a separate control unit although one is available as an option. As a standalone instrument the GEO-CROSSFLOW can be set-up and controlled using the utility software supplied, installed on a PC or laptop and connected via the USB connector.

GEO-CROSSFLOW can also be paired with a TSCU operator interface (Tunnel Sensors Control Unit), which is a remotely located control unit with a display, keypad and full range of interface capabilities to match those found in the GEO-CROSSFLOW itself. Since the TSCU has all the same interface abilities as the GEO-CROSSFLOW, interface connections can be made directly to the TSCU (which can be positioned at a convenient accessible location) and/or to the GEO-CROSSFLOW. This versatility offers the flexibility to accommodate a wide range of wiring schemes.

The GEO-CROSSFLOW monitor has no moving parts and no regular service requirement, making it a very reliable “fit and forget” monitor. The instrument performs a number of self-checking and diagnostic routines, which in the unlikely event of a problem, can identify the fault and report it via the service alarm relay and/or serial comms.

GEO-CROSSFLOW provides a reliable long term solution that is simple to install whilst requiring minimal service and maintenance. Plug and socket connectors and latched alignment brackets help to decrease the installation and maintenance time. An IP67 rating and the use of stainless steel ensures that GEO-CROSSFLOW can withstand the harsh environments and aggressive cleaning cycles found in tunnels.