Constant Height on a Sprayer
Keeping the spray boom at a fixed distance from the target surface. Because the nozzle cone is designed to give full coverage at a particular distance, when the height changes the coverage either leaves gaps or overlaps too much. That is why position control, not draft control, is used on a sprayer.
Nozzles spray at a particular angle; the intersection point of two neighbouring nozzle cones forms a uniform band at the right height. If the boom drops, an untreated strip is left between the bands; if it rises, spray drift and unnecessary overlap increase.
- A change of height leads directly to the application rate varying across the field.
- In wind, a high boom increases drift markedly.
- Boom levelness depends on equal adjustment of the lift rods.
An electronic retrofit kit does not measure boom height or correct it automatically. The benefit it provides is that you can move between the chosen transport and working positions with the same command every time. On a dial system the uncertainty of bringing the lever back to the same point by hand disappears; on the ELF-812 this is done with the joystick, and on the LFT series with the switch.
The context where this term is used: Converting a tractor hydraulic lever to electronic control