Flomec 490, Instruction Manual

Page: 13 / 20

Calibration 12
4.0 K
– FACTORS ( calibration factors for meter )
The K-factor (pulses / litre, gallon etc.) will vary in relation to the bore size of the pipe in which
the Insertion Meter is installed.
The K-factors and formula shown are a result of factory testing using smooth bore piping
under ideal conditions. Variations to the given K-factors may occur when using rough bore
piping or inadequate flow conditioning on either side of the Insertion Meter (refer clause 2.1).
In these instances on site calibration may be used to determine the K-factor.
4.1 Insertion Meter K- factors for common pipe sizes
For other pipe sizes below 610mm (24") not listed above, use the graphs and apply the
formula on the following pages ( 12 & 13 ).
4.2 K-factors for large pipes 460mm ID (18") and above use:
NOTE : K-factors for Reed Switch output are 1/3 the standard factors of the square wave
pulse output
Pulses per litre = 28647 ÷ pipe ID² (mm)
Pulses per M³ = 28647000 ÷ pipe ID² (mm)
Pulses per US gallon = 168.14 ÷ pipe ID² (inches)
Pulses per Imp. gallon = 201.94 ÷ pipe ID² (inches)
Pipe detail
NB pipe ID
inches mm p / litre p / m3 p / USgal p / litre p / m3 p / USgal
1.5" 40.9 18.678 18678 70.695 21.524 21524 81.468
2" 52.6 11.238 11238 42.534 12.818 12818 48.517
2.5" 62.7 7.880 7880 29.824 8.899 8899 33.682
3" 78.0 5.062 5062 19.161 5.676 5676 21.485
3.5" 90.2 3.768 3768 14.263 4.200 4200 15.896
4" 102.4 2.912 2912 11.021 3.233 3233 12.237
5" 128.3 1.839 1839 6.959 2.025 2025 7.665
6" 153.9 1.268 1268 4.798 1.402 1402 5.307
8" 203 0.719 719.0 2.721 0.787 787.2 2.980
10" 255 0.450 450.3 1.705 0.496 495.9 1.877
12" 303 0.316 316.0 1.196 0.347 347.4 1.315
14" 333 0.261 260.5 0.986 0.286 285.7 1.081
16" 381 0.198 198.0 0.750 0.217 217.0 0.821
18" 429 0.156 155.8 0.590 0.171 170.6 0.646
20" 478 0.125 125.4 0.475 0.138 137.8 0.521
24" 575 0.087 86.64 0.328 0.095 95.39 0.361
K-factors
( standard K-factors for square wave output only )
Schedule 40 pipe Schedule 80 pipe