In many large vegetable, flower and pot plant nurseries, a spray robot moves back and forth automatically along a pipe rail or monorail system. The spraying technique used should be matched to the crop. Techniques like on-demand spraying or the use of UV-C radiation are developing all the time. With good maintenance, a spray robot will last for at least ten years, but poor maintenance can slash its life span by half. Growers who take their maintenance seriously also get better spray results.

A spray robot consists of a hose reel plus a hose, a drive unit and a spray boom. The most widely used spraying techniques involve a spray boom with or without air assistance or fogging. There are two types of maintenance: daily maintenance after every use and periodic maintenance.

Daily maintenance mainly encompasses the spray system. Clean the nozzles and filter after every use. When cleaning the nozzles, make sure the O-ring doesn’t fall off and get lost. To prevent blockages, clean the nozzles in water with a brush or a compressor.

Then rinse the pipes through with clean water. Residues of spray liquid can clog the system, causing blockages that disrupt the distribution of the spray. Unscrew the filter housing, clean the filter with lukewarm water and replace the filter and the filter housing.

Every 50 hours

As a rule of thumb, the transport unit should be inspected, cleaned and lubricated after every 50 hours of use or once a month. Clean the machine with a wet cloth or hand brush and remove any crop residues.

The technical condition of the transport unit is an important factor. Wear and tear on the wheels (slippage) can change the speed of travel, and that in turn impacts on the delivery rate. The same applies to the pressure gauge: the pressure level determines the rate at which the spray liquid is delivered, so it is important to calibrate the pressure gauge once a year.

Also check the chain tension. Clean the motor fan grille: 10% contamination is 40% less air output. Clean the sensor eye and the reflector. Lubricate the bearings in the axles and joints of the transport system. Check the cables. Always follow the instructions in the user manual.

Inspection report

The sprayer unit should undergo a major service once a year. Follow the checklist supplied with the spray robot or engage a service engineer to ensure maximum operational reliability. The experts have more experience and look at other points besides those the person working with the machine may think of checking. Replace any parts identified as needing replacement in the test report.

It is also important to check the spray unit and the nozzles. The annual service should therefore also include a visual inspection of the nozzles to check that they are producing the correct spray pattern and a spot check of one or two nozzles. Replace nozzles as appropriate.

In the Netherlands, the Plant Protection Products and Biocides Act requires all spraying equipment that is at least three years old to undergo regular SKL (official quality control) inspections. An inspector from an approved inspection company checks that the equipment meets the quality requirements based on an inspection protocol.

Text: Marleen Arkesteijn.
Images: Micothon.