The Ultrasonic Doppler Instrument is a compact, easy-to-use system for measuring the water flow of open channels, pipes and nature streams. It is suitable for use in a wide range of water qualities, from sewerage and waste water to clean streams, potable water, and even sea water. The instrument may be programmed to compute Flow Rate and Total Flow in pipes and open channels.
Doppler ultrasonic sensors transmit an ultrasonic (sound) wave into the flow. This sound wave is reflected by acoustically reflective particles (e.g. air bubbles, suspended solids) and the instrument detects the reflected frequencies. The difference between the transmitted frequency and the received frequencies is directly proportional to the velocity of the stream flow.
In full or partially full pipes, the velocity of the stream flow varies markedly across the cross-section of the pipe. Typically, velocity is zero along the wall of the pipe and increases to a maximum at or about the centre of the pipe. Doppler ultrasonic sensors receive reflected frequencies from particles moving at these different velocities. The greater the area of flow moving at a particular velocity, the greater the number of reflections with the respective frequency shift. The average velocity of the stream is therefore calculated by averaging those frequency reflections received across the whole stream profile.
Doppler ultrasonic velocity sensors utilizing advanced signal processing technology “see” across the entire stream profile to give a true average velocity even with extreme turbulance . It is designed to be placed at (or near) the bottom of a water channel for “upward looking” measurement. By comparison, traditional insert devices only “see” a golf ball sized point of the stream flow around the sensor head then use complex algorithms to estimate average velocity.
Water velocity is measured by the ultrasonic Doppler principle which relies on suspended particles or small air bubbles in the water to reflect the ultrasonic detector signal. The instrument will not operate in very clean, “de-gassed” water. Water depth is gauged by a hydrostatic pressure sensor, referenced to atmospheric pressure through the vented power and signal cable. Water temperature is also measured so the instrument can adjust for the change in velocity due to speed of sound. Water temperature can also be logged.
Different version are available, depending on the requirements.
Practical Applications:
- Sewer Monitoring
- Storm water Monitoring
- Waste Water Treatment Plant Monitoring
- Natural Streams and Rivers
- Urban Drainage
- Run Off/Infiltration Surveys
- Irrigation
- Estuary and Tidal Studies
- Industrial Effluent Metering
- Nutrient Load Management
- Drainage
| Farm Outlet/Turnout Meter | Pump Discharge Meter |
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| Metering Lateral Diversions/Gross Water Off-takes | Farm Waste Meter |
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| Metering Water Flowing through a Road Culvert | Measuring Flow in Partially-Full Pipes |
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| Measuring Flow in Open Channels | Metering Mobile Irrigation Systems |
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Key Features:
- Measures flow and velocity, temperature and depth.
- Operates in water qualities from fresh water streams to primary sewage.
- Records data for up to 1 year (at 1 minute intervals)
- Low power consumption, operate for four months with optional internal battery – ideal for use in remote locations.
- Single velocity sensor can be used in full pipes
- Easy to install, easy to use and virtually maintenance free
- No measurable head loss
Specifications:
Probe(sensor)
Velocity
Range: 21mm/s ~ 10000mm/s
Accuracy: ±1%
Resolution: 1mm/s
Temperature
Range: 00C ~ 700C
Resolution: 0.20C
Water Depth
Range:0 ~ 10m
Accuracy: ±0.5%
Resolution: 1mm
Computation: Flow rate, totalised flow. Channel Type: Pipe, open channel, natural stream.
Communication: RS-485.
Cable: 10 metres.
Cable Options: User specified up to 100 metres.
Power Source: 12V DC
Power Usage: 11.5VDC to 15VDC, 200mA active, 60mA communications
Operating Temp: 0°C to 70°C water temperature.
Material: PVC body, stainless steel mounting plate
Dimensions: 290mm x 70mm x 25mm
Weight: 850g (2kg with 15m cable)
Datalogger
Power Source: 12V DC Power Usage: 11.5VDC to 15VDC, 6mA standby, 200mA active.
Protocol: MODBUS
Memory: 4MB
Serial output: RS485 or RS232, Data modem and GSM/CDMA support
Display: LCD screen
Working environment: temperature: -40 ~ +85 ℃; humidity: ≤ 95%.
Material: PVC
Size(LxWxD): 230mm x 180mm x 65mm
Weight: 850g