The level of sprayer filtration required for any given operation depends several variables. Potentially, there are opportunities to install filters at the tank opening (usually a basket), the suction-side of the pump, each section line, and behind the nozzles.
While I’ve yet to see an operation that uses all four (specialty or field operations), the suction filter and line filters are, to my mind, bare minimum. When I ask why operators don’t use nozzle strainers, the response is either “Because they plug” or “It’s one more thing to clean”.
Well, if your nozzle strainers are plugging, it’s likely because you have an agitation or mixing issue further up the line. They can handle a lot before the spray pattern begins to suffer … but you do have to clean them regularly so they can continue their good work. Running water through them just plugs them further, so they have to be removed when you pull the nozzles for cleaning.
Each level of filtration should get progressively finer, ending with the nozzle strainers being slightly finer than the nozzle orifice. Nozzle catalogues will often advise you on which strainer is appropriate for the nozzle you are using. This infographic explains how nozzle strainers are classified:
If you use an airblast sprayer, sometimes the filter shoulder plays a role is keeping the nozzle snug in the nozzle body, Without it, you may need additional gaskets to prevent leaks.
If you use a field sprayer with clean water, liquid formulations and large nozzles, you may never need nozzle strainers. But, if you’re using dry formulations, if your agitation is under-powered, or if your fill water is less than pristine (I’ve found frogs in sprayer tanks) then you might consider using them.