Are You Replacing Your Nozzles?

As I write this article, our agriculture community is alive with activity. Tractors are busily finishing the last of the planting, fertilizer trucks can be seen on the roadways moving from one location to another, and along with new crops comes the concern about controlling pests.   

Of course, pesticides are just one option available for controlling pests, and the equipment used to apply pesticide is just as important as utilizing the correct pesticide. Just like all equipment, spray rigs need maintenance and repair. It is recommended the spray rig be checked prior to and after extended storage, as well as after each use.  

Additionally, it is important to make sure to use personal protective equipment (PPE). Make sure to always wear PPE when checking, maintaining and repairing a spray rig.  

The next step is to make sure to check the system from the spray tank all the way to the nozzles, of course only with water in the system and never with pesticides. Look for damages and leaks to the spray tank, pump, pressure gauge, hoses, strainers, fittings and nozzles. All worn out parts, such as hoses, fittings, nozzles and others, should be disposed of properly and not reused for any other purpose. 

Worn nozzles 

Did you know a worn nozzle will still visibly show a uniform spray pattern? Often, we do not think about replacing nozzles until there is a non-uniform spray pattern. However nozzles are constantly wearing due to how many hours of spraying is done, if fertilizers are used and what types of pesticides are sprayed.   

To accurately determine if a nozzle is worn out or not, calibrate all nozzles against an identical new nozzle. This is done by catching the amount of water delivered from both the old and new nozzle for the same duration of time and at the same pressure in a measuring cup – typically captured in ounces. Any nozzle delivering 10 percent or more water than the new nozzle is worn out and should be replaced.   

For example, say the manufacturer states the nozzle should provide 40 ounces of fluid per minute at 35 pounds of pressure. Since 10 percent is the factor determining if a nozzle is good or worn, multiply the ounces by the factor – in this case, 40 ounces times 10 percent equals four ounces. Then, add and subtract the ounces on either side to determine the upper and lower range – this gives us 44 ounces on the high end and 36 ounces on the low end.     

Therefore, any flow collected for the duration of one minute at 35 pounds of pressure and is between 36 ounces and 44 ounces would be considered a good nozzle. Anything above or below this range would be considered a worn nozzle and should be replaced.   

Nozzles providing low flow could also be plugged. If this is the case, it would be worth cleaning the nozzle and testing it again. 

Nozzle lifetime 

Of course, not all nozzles are created equal. Nozzles are made out of five different materials:  Brass, plastic, stainless steel, hardened stainless steel and ceramic. In terms of cost, plastic nozzles are usually the cheapest and hardened stainless steel is the most expensive.   

In terms of durability, also known as nozzle life, brass is the shortest lived followed by plastics, stainless steel and hardened stainless steel, while ceramics are the longest living spray nozzle.   

Unfortunately, nozzle life cannot be reported in years of use due to variable factors such as how many hours of spraying is done, if fertilizers are used and what types of pesticides are sprayed. Nozzle life is typically compared against the expected life of a brass nozzle as a standard. For example, plastics are considered to have two to three times the life of brass.  

Consider the last time the nozzles were replaced on spray equipment. Properly maintained and calibrated spray equipment will save time, less headaches during application and assurance of correct application. So, I recommend carving out some time this spring and get all the spray equipment maintained and ready for the busy season ahead.     

Jeremiah Vardiman is a University of Wyoming Agriculture and Horticulture Extension Educator. He can be reached at jvardima@uwyo.edu.