DRAFT
If a new sprayer is being designed or an original pump is to be replaced, it is suggested that a diaphragm or centrifugal type is chosen. This should be able to provide a pressure of about 1 – 3 bar (15 – 45 psi) and should be capable of delivering the maximum flow rate of the sprayer plus the flow required for tank agitation (if a mechanical agitator is not used). An output of 60 l/min is satisfactory for most low volume sprayers without mechanical agitation.
A chemical on/off valve must be fitted in the main feed to the sprayheads. This may be mechanically or solenoid operated. A
A filter must be incorporated in the chemical supply to the sprayheads. This should have an 0.5 mm (50 mesh/inch) or finer mesh filter. The filter may be installed either in the suction or pressure line of the pump but the filter must always be before the flow restrictors and should preferably be before the pressure regulator. Fig 8 shows the recommended chemical feed configuration for a typical sprayer.
SPRAY HEADS
CHEMICAL |
|
TANK | PRESSURE |
| GAUGE |
CHEMICAL PUMP |
|
SUCTION STRAINER |
|
| ON/OFF AND |
| PRESSURE |
| CONTROL |
RETURN LINE TO AGITATOR | VALVE |
| FLOW |
| RESTRICTORS |
Figure 8. Typical configuration of chemical feed to heads
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