Operational efficiency

Operational efficiency will be improved if stoppages in the field can be minimized and filling times reduced. Blocked nozzles are the greatest cause of downtime when spraying. Effective mixing, agitation and filtration are necessary to reduce downtime through blocked nozzles.

Filtration

The importance of the use of an effective filtration system cannot be over emphasized.  There are several filters and filter kits available which have helped alleviate the problems of blockages.  A double system is best, using 100 mesh washable filters for tank filling and in-line screening.  A second in-line 100 mesh filter can be fitted between the pump and nozzle.  Use fine filters early in the system to support the nozzle filters.  In-line filters should be cleaned regularly, preferably at each filling, and should not be left to dry out without cleaning.

Filling

Concentrate siphon probes decrease the risk of chemical contamination and, when calibrated, simplify formulae mixing.  They are commercially available for both standard 20 l metal containers as well as PVC type containers.  Probes are available as part of the filling system on some sprayers (for example, computer sprayers).  Homemade versions fitted into the filling pump line are also effective.  Contractors tend to use separate concentrate filling systems.  Electrically driven gear pumps and a flow meter mounted as part of the spraying unit give satisfactory performance and life.

Flushing

The fitting of a flushing out system allows for stationary washing out of lines and fittings with clean water.  A flushing system allows for safer unblocking and changing of nozzles as well as stationary calibration of computer sprays.  A flushing out system makes the checking of nozzles much simpler.  If used regularly, nozzle blockages should decrease.

Fittings

Quick change fittings are essential.  Snaplock or camlock type fittings save time at filling and also decrease the chance of spillage.  Gate valves should not be used in the system as it is too difficult to tell if they are on or off, and they take extra time to close.  Directional indication taps are better.