Posted 4/8/2021 09:23 (#8939544 - in reply to #8939150) Subject: RE: What kind of nozzles do you suggest?
Yup, there isn't a ton of options out there for variable rate fertilizer application. The spring-based VR nozzles can be fairly finicky (spring pressure might vary a bit, especially over years of use, and pressure consistency between sections is critical).
For the elastomer orifice type from Teejet, they are a good product. Sound engineering on the function. They are pretty much the reverse of what some dishwashers do to ensure proper pressure. There is just an elastomer orifice that opens up with more pressure to let more flow rate through. It is still key to have a really good idea of where your pressure drop might be over your boom.
I haven't seen anything as much as lifetime consistency of the orifice as I'd imagine it'd still have risk of hardening over year(s), but overall its probably as consistent as you can be in the field with a 'nozzle-controlled' VR compared to like a system controlled VR (via PWM solenoid, etc).
As far as flow ranges, there is also a fair bit of swing for flow rate between a fixed metering orifice size, but you are restricted to the rule of 'to double the flow, you have to quadruple the pressure'. So, usually the higher flow nozzles, the bigger flow range you have.
e.g. small 3gal nozzle could only go up to like 4.5 gal comfortably with pressure change, BUT a 20 gal nozzle can go up to 30GPA with the same pressure change.