Calibration Valmar
New Product Calibration
When applying product that is either not listed on the Product Flow Rate Charts (such as grass
mixtures) or that is inconsistent with the charted values, it is necessary to create a flow rate chart. Use
the following procedure to prepare flow rates for all possible gearbox settings.
Calibration Set-up
Follow the same procedure as given at the beginning of this chapter.
Calibration
1. Set the gearbox to Low Ratio, Range B, Speed No. 8. At this setting the gearbox input to output
ratio is 1 to 1.
2. Turn the crank the number of turns indicated in the chart at the beginning of this chapter.
3. Weigh the calibration containers. Subtract the weight of the empty containers to find the actual
application rate in pounds per acre at the gearbox setting indicated in Step 1.
4. Record this weight on the blank Product Flow Rate Charts on the next two pages in the Calibration
Weight column.
5. Multiply this calibration weight by the Gearbox Adjustment Factors listed on the chart in order to
calculate the actual application rate in pounds per acre for all the other gearbox settings.
Example Calculation (Table 5-1)
A grass mixture is to be applied at 1.8 pounds per acre. A calibration was performed in which 6 pounds
of product was collected.
Therefore, the application rate was 6 lbs/acre in Low Ratio, Range B, Speed No. 8. This weight was
recorded in the Calibration Weight column of the blank charts. This weight was then multiplied by each
Gearbox Adjustment Factor in the chart to calculate what the flow rate would be at all the other gearbox
settings. It was found that Ultra Low Ratio, Range B, Speed No. 3 was the correct setting for 1.8
pounds per acre of the grass mix.
The gearbox was set to Ultra Low Ratio, Range B, Speed No. 3 and an applicator calibration performed
as a final check.
Product Flow Rate Chart in lbs / Acre
Metering Gearbox Setting
Product
No. 1 No. 2 No. 3 No. 4 No. 5 No. 6 No. 7 No. 8 Input
Ratio
A B A B A B A B A B A B A B A B
Gearbox
Adjustment
Factor
.25
.26
.28 .29
.30 .32 .34 .35 .37
.39 .41 .43 .45
.47 .50 Ultra
Low
Ratio
Product
Cal.
Weight
XYZ 6 1.5
1.6
1.7 1.7
1.8* 1.9 2.0 2.1 2.2
2.3 2.5 2.6 2.7
2.8 3.0
Table 5:1: Flow Rate Example Calculation
*Calculated from .30 X 6 = 1.8 lbs/acre
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