Greyline Instruments OCF 5.0, User Manual

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Page 22
OCF 5.0 Open Channel Flow Monitor
TYPICAL SENSOR POSITIONING
FOR FLUMES AND WEIRS
Always refer to the flume or weir manufacturer’s instructions for correct measurement point upstream
from the flume or weir. Location of the sensor is critical for accurate flow measurement.
If manufacturer’s instructions are not available, the following guidelines are generally accepted.
1. PARSHALL FLUME:
Position the sensor at 2/3 Approach as
illustrated above. Sensor height must be
8" (203 mm) or more above the highest
water level.
2. PALMER BOWLUS FLUMES:
Position the sensor at ½ the flume
Diameter upstream from the throat of
the flume. Sensor height must be 8" (203
mm) or more above the highest water
level.
3. V-NOTCH WEIRS
Position the sensor at 3 x maximum Head
upstream from the weir plate. Sensor height must
be 8" (20.3 cm) or more above the highest water
level.
STILLING WELLS
Stilling wells are recommended to reduce the effects of turbulence as water flows through the flume or weir. The
OCF 5.0 sensor is centered over the stilling well. Sensor height must be 8" (203 mm) or more above the highest
water level. The well must be kept clean of sediment and deposits on the side walls.