What’s the difference between Flat and Cylindrical?
The smaller sampling volume of the flat sensor makes it very much more suitable for shallow flows, or measurements in confined spaces. However, it is also very much more sensitive to turbulent flows, which may manifest as apparently noisy real time readings. This effect can be minimised by using a long (>30secs) average period. The larger sampling volume of the cylindrical sensor effectively eliminates the turbulence noise, but also means that a greater depth of water is required for measurements.
The Model 801 Flowmeters are supplied with a dedicated Control Display Unit that both drives the sensor and provides data display of the measured water velocity. Data is updated at 1Hz, and may be averaged over any number of seconds from 1 to 600. The display will show real-time speed data at a resolution of 1mm/s, as well as the result of the data average, and a Standard Deviation figure to give added data confidence. A solid state memory records all results (up to 999 averaged readings), and the data may be downloaded to PC using
the RS232 interface lead supplied.
Both instruments are calibrated at Valeport’s own premises up to speeds of 1m/s. Higher speed measurements are based on linear extrapolation. Specific high speed calibrations can be arranged at a third party facility on request.
Control Display Unit
244mm x 163mm x 94mm, 2kg
Sealed to IP67
8x alkaline C cells, up to 37 hrs operation
-5°C to +50°C (display unit)
-5°C to + 40°C (sensor)
Both instruments are available for use as hand held “Wading Sets” only, with the operator standing in the channel, holding the instrument in position. The system is supplied with 1.5m wading rod (3x 0.5m sections), graduated in cm, and a 3m
cable from instrument to display unit.
Alternatively, a “top-setting” wading rod system is available, which allows the vertical position of the instrument to be set without removing the wading rods from the water.
System is supplied with CDUExpress Windows-based PC software, for data extraction from the display unit. CDU Express is licence free.
62 x 42 x 34cm, 9kg (wading set)
Single Axis - Cylindrical Sensor with Control Display Unit,
interface cable and operating manual in an ABS transit
Single Axis - Flat Sensor with Control Display Unit, interface
cable and operating manual in an ABS transit case
The above systems are supplied with:
· 2, 5 or 12m cable (different lengths on request)
· Wading rod set
3x 0.5m graduated rods, base and direction knob, in a canvas carrying bag
Wading Rod Set supplied with:
· 3x 0.5m graduated rods, base and direction knob, in a
canvas carrying bag
Top Setting Wading Rod Set for use with standard wading
rod set consisting of:
· 3x 0.5m graduated rods and necessary mounting
brackets, in a canvas carrying bag
Large transit case for instrument and wading rods
External DC power option (includes DC power input lead)