19
F L O W C A L I B R A T I O N
Flow constant
F L O W C O N S T A N T
x x x . x PPU
The flow transducer can be calibrated theoretically or with two practical
methods. For the sake of accuracy, the practical methods are preferred. Practi-
cal calibration is done with clean water. The Flow Tank method is more time
consuming, but is more accurate than the Flow Nozzle method.
When changing to nozzles with more than a 100% increase or decrease in out-
put, it is recommended to re-calibrate the flow transducer.
Calibration is recommended to be carried out at least once during the spray-
ing season.
Use the chart at the back of the book to record the values.
Flow constant
To change the flow constant theoretically.
During theoretical flow calibration the
number of pulses per unit are shown
on the display.
For example, [
120.0 PPU
] indicates
the number of pulses which theoreti-
cally come from the flow transducer
whilst 1 litre of liquid passes through.
Approximate PPU values for different
flow housings are as follows:
H
ousing
Housing
Flow range
Orifice
PPU
identification
l/min
mm
value
S/67
One outside groove
5 - 150
13.5
120.00
S/67
No groove
10 - 300
20.0
60.00
S/67
Two outside grooves
35 - 600
36.0
