Cleaning Inside the Sprayer

Label guidance

If a specific cleaning method is given on the label then this must be followed. What follows is for general guidance only.

Always remember to wear gloves, face shield and plastic apron/appropriate waterproofs when cleaning.

Residual volumes within the sprayer

Sprayer cleaning begins with accurate calibration: when flow rates are as expected there should be very little spray solution left in the tank at the end of the job.

Encourage in-field cleaning

The emphasis today is on in-field cleaning using dedicated equipment on the sprayer. A dedicated rinse tank mounted on the sprayer is the key quick and easy field cleaning.

Dilute any small amounts of liquid left in the tank with clean water, then spray it out in a way that complies with its approved use and avoids over-dosing plants. Diluted 10 times and sprayed over the just-treated area will often meet that requirement simply and effectively.

Otherwise, larger residual volumes can be drained and disposed of by an authorised company.

Infield rinsing with rinsing tank (a daily routine)

The most efficient use of water in the rinse tank is achieved if the water is used in 2 to 4 lots; using half, one third or one fourth of the water for each rinsing. It is important that all valves are operated whilst rinsing so that trapped spray solution is removed from everywhere in the system.

If the sprayer is equipped with a rinsing nozzle this should be activated during each rinsing to achieve the most efficient cleaning of the internal spray tank. It is important that the sprayer is emptied as much as possible after each rinsing to ensure maximum dilution with each new introduction of rinsing water. Spray the rinse water out over an area of the crop just treated, ensuring the maximum dose for the product won't be exceeded.

Rinsing without rinsing tank (daily!)

To minimise the amount of rinsing water being used and disposed of, the tank should be flushed internally using the equivalent of 10% of the tank volume. This is repeated twice.

A high pressure cleaner is also useful. After each rinsing, the rinse water should be sprayed out over the just-treated crop, a similar area, or an area of low-valued vegetation. Before applying the rinsing water over the crop, all valves must be activated for a complete rinse.

However you dispose of the rinse water, it must comply with your local rules and regulations. In particular, make sure no rinse water could end up in ditches, drains or waterways.

When switching from one product to another, it may be necessary to chemically break down the smallest traces of active chemical that are stuck to the structures of the sprayer. Follow any recommended procedures detailed in the agrochemical label or documentation.

Otherwise, there are 2 possibilities:

Cleaning without rinsing nozzle: Fill the spray tank with water and an approved cleaning agent like ammonia, bleach or a product marketed for sprayer cleaning. Turn on the pump and let the solution circulate through the whole system for 15 minutes.

Be sure to operate all the valves – on sprayers with a self-cleaning filter, increase pressure until the safety valve is activated, then reduce the pressure again. To ensure that the tubes and hoses on the boom are also cleaned remember to let the nozzles spray onto low-value grass for a while. Leave the sprayer for a couple of hours to ensure that any chemical residues of chemicals are deactivated, then spray the cleaning solution onto a dedicated grassed area.

Dismantle and remove all filters and nozzles and place them in a container of the same cleaning solution as used in the spray tank to soak. Then give them a final clean with a brush, before rinsing them in clean water and fitting them back on the sprayer. Finally, rinse the entire sprayer (inside and out) with clean water, and spray this rinse water onto an area of low-value grass.

Cleaning with a rinsing nozzle: Fill the tank to 1/10 of the capacity with water and cleaning agent. Activate the rinsing nozzle and let the liquid circulate in the whole liquid system for 15 minutes whilst operating all handles and valves. Then follow the same procedure described above for emptying the tank and cleaning the nozzles, etc.