T/FL-US – AIR FLOW MONITORING SYSTEM
Accurate ultrasonic air flow measuring system based on different transition times of ultrasonic pulses. Reliably measures the average air flow over the whole tunnel cross section.
Description
Air flow measurement based on difference of transition times of ultrasonic pulses
The air flow monitoring system measures the air flow based on different transmission times of ultrasonic pulses sent in one or the other direction. This cross section measurement delivers the average air speed more reliable and meaningful than methods that measure only one or two points on the tunnel wall.
Two sensors are mounted below the tunnel ceiling, cross section with an angle of 30° to 60° (usually 45°) such that a vector component of the air flow overlaps the direction of the ultrasonic sound pulses exchanged by the two sensors.
Air flow in the tunnel influences the transition time of the pulses between sender and receiver. Based on the difference in transition times of ultra-sonic pulses sent in one or the other direction the measured values are calculated. Measured values are air speed, air flow rate, direction of air flow and air temperature.
Features:
- Accurate ultrasonic air flow measuring system based on different transition times of ultrasonic pulses
- Measurement of average air flow over the whole tunnel cross section
- Sensor setup via service interface
- • Suitable for tunnel cross sections up to 18 m (Measuring path up to 25 m)
- Connection to tunnel control system either via analogue output and relaysor via RS-485 MODBUS RTU
- Visible LEDs to indicate sensor status
- Corrosion-resistant non-wearing polyamide membranes
- Optional, remote touch operating unit to display measured values and to modify parameters
System:
- Two sensors (master & slave)with mounting clamps mounted below the tunnel ceiling in an angle of30° to 60° to the tunnel axis
- Terminal box for master to connect the power supply and the connections to the tunnel control system and the slave
- Terminal box for slave
- Optional remote touch operating unit
Advantages:
- Specifically designed for application in tunnels
- No control unit required
- Easy configuration
- Corrosion resistant against aggressive tunnel atmosphere
- Sensors can be replaced quickly with no tools and no realignment required
- Proven in high speed train tunnels with train speeds up to 350 km/h
- No expendables (e.g. ultrasonic membranes)
- Extremely low maintenance requirements
Technical Specifications:
| AIR FLOW MEASUREMENT | |
|---|---|
| Measuring method | Determination of direction dependant differential transition times of ultrasonic pulses |
| Measured values | Air velocityVolume flow
Direction of air flow Temperature |
| Measuring range | -40 .. 40 m/s |
| Resolution | 0.1 m/s, accuracy dependent upon measuring distance, flow profile, installation, typically 170.000 h within service life if used within specifications |
| IP rating | IP 67 |
| Dimensions | 270 x 130 x 95 mm |
| Weight | Sensor approx. 2.2 kg each + wall bracket 1.6 kg |
| Material | Stainless steel 1.4571 (AISI 316Ti) Polyamide RAL5017, Flammability rating: B1 (UL 94 V0) |
| TERMINAL BOX | |
|---|---|
| Type | t/FL-US-TB-SS-A and t/FL-US-TB-SS-B |
| Operating voltage | 90 .. 264 VAC, 48 .. 62 Hz |
| Power consumption | approx. 30 VA (for master, for slave only optionally) |
| IP rating | IP 69K |
| Dimensions / Weight | 160 x 250 x 110 mm / 3.2 kg (Master) 160 x 160 x 110 mm / 1.9 kg (Slave) |
| Material | Stainless steel 1.4404 (AISI 316L) |
| Mounting | incl. mounting clamp made from stainless steel 1.4404 for wall mounting |
| CONFORMITIES | |
|---|---|
| Electrical standards | 2014/35/EU Low Voltage Directive (LVD) 2014/30/EU Electromagnetic compatibility (EMC) IEC 61326-1:2012 IEC 61010-1:2010 |
| Tunnel safety | AT: RVS 09.02.22 and ASFiNAG PlaPB DE: RABT 2006 CH: ASTRA RL 13001 and FHB BSA |
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