Big Blue Flume Notes

               Left Manometer
               :   :
               :   :
               :   :
    ^          :   :
    |          :   :Large Orifice
    X----------+=O=+----------------------< Pump 2
    !
    !
    ! 
    !                 Right Manometer
    !                 :   :
    !                 :   :
    !   ^   ^         :   :
    !   |   |         :   : Small Orifice
    !   X-------------+=o=+-----+
    !   !   |         :   :     |
    !   !   X---------+=O=+-----+---------< Pump 1
    !   !   !     Large Orifice 
    !   !   !       (Behind)
    !   !   !
   (*) (*) (*)

• Flume Width: 1 ft
• Flume Depth: 1.5 ft
• Slope: -5% to +15%
• Maximum Flow: 0.42 ft³/sec using both pumps¹⁾

The manometers are mislabeled. Open the valves on the left manometer to measure the flow from pump 2. Use the right manometer to measure the flow from pump 1. The upper and lower sets of valves on the right manometer select which orifice the manometer is measuring; open only one of these two valve sets at a time on this manometer to select which orifice flow you are using to measure the flow from pump 1. There is no point to using the front set of valves on the right manometer to measure the flow from the small orifice since the small orifice valve is broken.

The small orifice valve is broken. Do not use it If it worked, the small orifice could used for lower flow rates, and to make fine adjustments to a larger flow when used in combination with pump 2.

The manometers function as differential manometers.²⁾ Read them with the stopcocks closed. The value to read is the difference between water levels in each pair of tubes. You may open a stopcock briefly with the corresponding pump running to help purge the manometer of air and to raise the water level on the scale. If the water level goes too high, lower it by opening the stopcock with the corresponding pump switched off. If left open when the pumps are running, the stopcocks will dribble or spurt water all over.

— David Wagner 2007/10/17 03:06