Nozzle selection

The nozzle is one of the most important, least expensive and often the most neglected components of a spraying system.

Nozzle design and spray distribution patterns

Various types of nozzles for pesticide application are available but most nozzles for plant application are usually of three types.  The table below details the most common use, the typical operating pressure and expected droplet size of these three nozzle types.

Nozzles and strainers should be cleaned regularly and nozzles checked for both evenness of output as well as total output.  Nozzles which deviate by more than 5% from the average should be replaced and all nozzles discarded when either their output or fan angle differs by more than 15% from new.

When water volumes are decreased, the fan angle of the nozzle needs to be increased to produce sufficient droplets in the working range.  For water volumes greater than 50 l/ha, either 80 or 110 degree nozzles will produce enough droplets to give sufficient coverage.  However, at volumes less than 50 l/ha, or where drift may cause problems, 110 degree nozzles are preferable.

Nozzles are made from a wide variety of material including brass, plastic, stainless steel, ceramic and sintered aluminum.  Whilst there is a difference in the initial price, the added life attained by selecting material such as sintered aluminum far outweighs the initial cost.  Sintered aluminum nozzles are approximately three times the cost of brass, but will possibly give ten times the life.

Nozzle identification

Nozzle tips come in many different shapes, sizes and colors and carry different markings

Most nozzles will have markings that indicate the manufacturer, spray angle, spray volume, the material that is made from. Some manufactures use different color coding to indicate different capacities within their range.

A typical nozzle may have the following markings

TEEJET 110-01-FF-HS

Where:

TEEJET= manufacturer
110 = spray angle
01  =  spray volume
FF =  flat fan
HS = hardened stainless steel