Cleaning Sprayers (from Cornell)

[Allan Balliett]

Decontaminating and Storing Sprayers
Dr. Andrew Landers, Cornell University

Sprayer Decontamination and Maintenance: Sprayers must be thoroughly decontaminated, inside and outside, after use. Regular maintenance of spraying equipment will prolong its life and ensure accurate trouble-free operation. This allows spraying to be done with the minimum loss of time and taking full advantage of favorable weather conditions.
NOTE: Read the manufacturer's instructions before beginning to wash out a sprayer. Wear protective clothing appropriate to the pesticide which has been used. This may include an apron, rubber gloves, boots and face shield.
It is important to clean everything thoroughly including associated equipment such as mixers, the site where mixing and filling is done, and, of course, yourself.
Dispose of Pesticide Waste: REMEMBER: Cleaning up should be done in such a way that washings DO NOT enter public sewers or any water courses, not fields which have under-drainage and certainly not catchment areas for boreholes or wells.
The safe disposal of pesticide waste is a serious responsibility for sprayer operators. It is important, therefore, that everything should be done to keep waste generation to a minimum. Remember that pesticide waste is of four types:
1. Concentrated products
2. Diluted pesticides including washings
3. Empty containers
4. Contaminated clothing and other materials
Try to keep the volume of tank washings to a minimum. Special low volume, inexpensive washing systems are now available which consist of a spinning nozzle(s) mounted in the tank. The device can be connected to a hose or water tank. Water passes through the rotating nozzle(s) and cascades down the inside walls of the tank.

Preparation for Storage: Any spray liquid or contamination left in the tank should be disposed of correctly. Remove tank drain plugs or open drain cock. Hose down the inside and outside of the tank, including the tank top. Scrub where necessary or use a low volume pressure washer. Replace drain plug or close drain cock. Remove the suction, main and in-line filter elements. Wash them thoroughly in clean water with a soft brush and replace. Remove nozzles, nozzle filters and nozzle bar end caps if they are so fitted. Soak them all in a bucket of water with a material recommended for cleaning of spray machinery. Scrub clean with a soft brush. Partly fill the tank and pump out to flush all parts. Ensure that you open and close boom valves a few times during the flushing to clean out crevices. Refill the tank with clean water or a recommended cleaning agent. There are about a dozen commercial tank cleaners designed to remove or neutralize most of the modern low-rate chemicals. If no cleaning agent is available, one gallon of household ammonia per 50 gallons may be used. DO NOT use chlorine-based cleaners such as bleach. Re-circulate for 15 minutes, then pump a quantity through the pipes and booms. Leave the remainder for as long as practicable; overnight if possible. Discharge at least on quarter of the contents of the tank through the booms and drain the rest. Check that no deposits remain in the tank or filters. If any remain, hose them down and scrub them off. To ensure thorough cleaning and decontamination, the last three steps can be repeated. Store nozzles and filters in a safe place. Leave valves open and the tank lid loosely closed. Ensure that the sprayer and all parts are completely empty of water, especially the pump. If you are unable to completely drain the system, you can use an antifreeze solution. An environmentally safe antifreeze diluted to 50% may be acceptable. Hose down the outside parts of the sprayer, scrubbing if necessary. Ensure that the sprayer is parked safely and securely. Wash down waterproof clothing, apron, boots and face shield. Wash outside and inside of gloves with soap and water and rinse and dry them. Finally, thoroughly wash your face, neck and hands with soap and water.
Mechanical Maintenance: Lubricate all appropriate parts prior to storage. Check oil levels. Check soundness of all components, particularly booms and boom hinges. Electrical connections and components which control valves, spray monitors, etc. should be cleaned and protected as directed by the owners manual. Check wheels, wheel bearings and tire inflation.
Storage of Sprayers: Store sprayers under cover, taking care to prevent dirt and moisture from affecting the tank or working parts. Remember sunlight softens and weakens rubber materials and can degrade plastic materials. Storing in a building also allows you the opportunity to conduct any routing or pre-season maintenance.