DRAFT
5.Calculate the output of each sprayhead by dividing the total output of the sprayer by the number of sprayheads.
Example: |
| 16 l/min from sprayer | ||
Output: |
| |||
No of sprayheads: | = | 8 | = | 2 l/min |
Output/sprayhead | 16/8 | |||
6.Select the correct fixed restrictor orifice to give the required flow rate per sprayhead at the normal working pressure of the sprayer (typically about 2 bar or 30 psi). Table 3 gives the typical flow rates for fixed restrictor orifices. These figures are based on measurements with water. Actual flow rates may differ according to the viscosity of the chemical being used.
Table 3. Approximate flow rates for fixed restrictor orifices
RESTRICTOR No. |
| FLOW RATE (litres/minute) |
|
| 1 Bar (15 psi) | 2 Bar (30 psi) | 3 Bar (45 psi) |
10 | 0.30 | 0.42 | 0.51 |
48 | 0.62 | 0.87 | 1.07 |
55 | 0.81 | 1.14 | 1.40 |
86 | 2.05 | 2.90 | 3.55 |
7.Fit the appropriate orifice in the fixed restrictor of each sprayhead.
8.Place a container under each sprayhead.
9.Ensure that the chemical on/off valve is closed.
10.Fill the tank of the sprayer with at least 50 litres of the chemical to be used or a liquid of similar properties.
11.Start the chemical pump of the sprayer but do not run the hydraulic system.
12.Open the chemical valve until all air is purged from the hoses and sprayheads. Return the chemical collected in the containers to the tank of the sprayer.
13.Place the containers back under the sprayheads and open the chemical on/off valve again and collect chemical for a measured time of one or two minutes. Use a measuring cylinder or calibrated container to measure the output and calculate the flow rate in litres per minute per sprayhead.
14.Check that the flow from each sprayhead is the same and compare the total measured output rate from all the sprayheads 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 spray chemical pressure.
16.If this adjustment is insufficient, the restrictor orifice for each sprayhead 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
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