11
6.Fit a restrictor tube (8) to the outlet of the valve. Tighten the cap nut (14) firmly by hand.
7.Push a 15 cm (6") length of 6 mm (¼") inside diameter plastic hose over the restrictor tube.
8.Ensure that the chemical on/off valve is closed.
9.Fill the tank of the mistblower to half its normal working capacity with the chemical to be used.
10.Start the engine of the mistblower and run it at the correct operating speed (see section 4.1).
11.Support the sprayhead at its normal operating height.
12.Place a container under the tube fitted in step (7) and open the chemical on/off valve until all air has been purged from the hose and valve. Close the valve.
13.Open the chemical valve again and collect chemical for a measured time of one or two minutes. Use a measuring cylinder or calibrated container to measure output rate in litres per minute.
14.Compare the measured output rate with the calculated rate from step (4).
15.If the actual output is slightly too high or too low, it may be possible to adjust it by varying the tank air pressure control of the mistblower.
16.If this adjustment is insufficient or does not exist, the restrictor tube must be changed to a smaller size to reduce the flow or a larger size to increase the flow.
17.The flow must always be
The above procedures assume that the operator can walk at a steady speed whilst spraying. This may not be possible under some circumstances, such as when spraying large trees. In these cases, the calibration and spraying techniques should be modified as follows:
1.Calculate the number of trees per hectare.
2.Divide the chemical application rate in litres/Ha by the number of trees per hectare to give the dose of chemical per tree.
Example:
Planting: |
| 400 trees/ha |
| |
Application rate: | 200 litre/ha |
| ||
Dose | = | 200 | = | 0.5 litre/tree |
|
| 400 |
|
|
3.Measure the time taken to spray one tree from all directions. Note that an adequate time must be allowed for the airstream to carry spray droplets into the higher foliage.
4.Calculate the flow rate required to deliver the required dose in the measured time.