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I Instruction manual VWR
®
Media Pump
At one point, the screen shows:
The button “fill tube” is at the top left side of the screen. Place the nozzle in a “waste” bottle. Press this button if
the tubing is not totally filled with liquid. Keep your finger pressed until the tubing is filled.
Be careful not to fill up the container during the operations!
Then press “START/STOP” (or on the rotating button) to start the pump and press again to stop it.
Finally, following the instructions displayed on the screen, you will successively:
• weigh the dispensed liquid
• enter its density
• enter its weight
The calibration is then done. Media Pump displays the obtained precision on screen. According to the functioning
mode, it shows:
• Continuous mode: precision on the flow measurement
• Doses mode: precision on the volume of a dose
Example:
Test
If you want to test the calibration you just made, turn the button to select “TEST” and validate. Place an empty
container, possibly calibrated beforehand and then press the button. The pump activates itself and dispenses the
theoretical volume of a dose. Check, possibly by weighing, the volume of the poured liquid.
Calculation of accuracy
The accuracy depends on 2 things:
• tubing inner diameter
• dispensed volume during calibration
Tubing inner diameter:
The tubing inner diameter is important in the dose mode. It must be adapted to the volume of the wanted dose:
for a small volume, the tubing must be thin. If you use a large tubing to dispense a small volume, inaccuracies
may increase.
Dispensed volume during calibration:
Theoretically, the flow measurement after calibration is more precise after you have dispensed a large volume
because you would have measured the real flow during a longer time.
However all the phases of the movement of the pump: start, stop and continuous rotation, are also important in
the precision of the volume used. Therefore, it is better that the volume dispensed during calibration be equal to
the volume dispensed during use. That is to say:
• Dose mode: the volume of a dose
• Continuous mode: the volume the most often dispensed
Accuracy displayed by the Media Pump is calculated on the basis of two parameters discussed above (tubing
diameter and volume added).
C A L I B R A T I O N
P R E S S F I L L T U B E
T O A V O I D A N Y
A I R B U B B L E S
E N T E R
C A L I B R A T I O N
D O N E
PRECISION : 0. 77%
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