18
Measuring Method
5.7 Air bleeding
Bleed the air inside the piping completely and the On-Board Volumetric Flow Detector before starting measurement. If
the air is not vented completely, it might cause measurement errors and/or fluctuation in the instantaneous flow rate.
Please note that the air bleeding procedure with and without a bypass valve are different from each other.
Air bleeding procedure with a bypass valve
[1]
Bleed the air out of the piping.
First, pour the liquid to be measured with the bypass valve fully open.
Next, with the bypass valve open, keep pouring the liquid. This releases the air out of the piping in front and to the
rear of the detector naturally.
[2]
Bleed the air out of inside the detector.
After checking that the air has been vented out of the piping and the filter, close the bypass valve gradually. This
bleeds the air out of inside the detector.
When bleeding the air out of inside the detector, pay attention not to pour a large amount of liquid. Remember to
adjust the opening/closing of the bypass valve while checking the instantaneous flow value with the Ono Sokki DF-
2200 On-Board Flow Meter or the FM Series Digital Flowmeter.
Finally, close the bypass valve completely. By following the procedure below, the air can be bled completely out of
inside the detector.
OUT
IN
Bypass valve
FP-4135 On-Board Volumetric Flow Detector
(flow detecting part)
!
CAUTION
•
While the liquid to be measured is being poured, the instantaneous flow rate value of the Ono Sokki DF-2200 On-Board Flow
Meter or the FM Series Digital Flowmeter might fluctuate. This phenomenon is seen when the air is not bled completely.
Repeat the procedures “Air bleeding procedure with a bypass valve” on page 18 to bleed the air.
Air bleeding procedure without a bypass valve
[1]
Bleed the air out of the piping and the inside of the detector.
Increase the poured amount gradually being careful not to pour a large amount of liquid.
Finally, keep pouring the large amount of liquid. By following the procedure below, the air can be bled completely
out of inside the detector.