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How to Maintain a RBC Flume

For proper flow measurement, a RBC flume installation must be periodically inspected.  

This inspection should include the channel in which the flume is installed, the flow entering / exiting the flume, and the flume itself.

Channel inspection

  • The upstream channel banks should be clear of vegetation or debris that could affect the flow profile entering the flume (upstream) or restrict flow out of the flume (downstream).

  • Inspect the upstream channel to make sure that flow is not bypassing the flume.

  • Inspect the downstream channel to make sure that scouring is not occurring.

  • Any hydraulic jump should be at least 30 times the maximum head (Hmax) upstream of the flume.

Flow inspection

  • Flow entering the flume should be tranquil and well distributed.  

  • Turbulence, poor velocity profile, or surging should not be present.

  • The Froude (Fr) number should, ideally, be 0.5.

  • As the Froude number increases so does surface turbulence.

  • Flumes accelerate sub-critical flow (Fr < 1) to a supercritical state (Fr 1>) .  

  • Flumes experiencing flows greater than unit (Fr = 1) will not accurately measure flow.

Flume Inspection

  • Flumes must be level from front-to-back and from side-to-side.  

  • Earthen installations are particularly susceptible to settling due to wet / dry and freeze / thaw cycles.  

  • Flow surfaces are to be kept clean of surface buildup or algal growth.  Scrubbing or a mild detergent can be used. 

  • Galvanized flumes should be checked for corrosion.  

  • Any corrosion should be removed and then cold galvanization applied to the area.