Quick chem arrival
Quick chem arrival
ONE of the main problems of using chemical injection systems for variable rate applications and spot treatments is there is usually a delay in the time taken for the chemical to arrive at the spray nozzles after it has been injected into the pipelines.
A 24m-boom sprayer with a conventional injection system could take as long as one minute before the required chemical arrives at the nozzles, according to Knight Farm Machinery boss Brian Knight.
When spraying at low volumes this could mean the sprayer has travelled 150m, even though the injector unit may be mounted as close to the booms as possible.
Some companies have attempted to overcome the problem by fitting navigation systems which compensate for the time delay in distance travelled.
"Trying to compensate for time delays in a navigational sense is difficult because it would generally mean that spot applications cannot be made within a reasonable distance of the headlands," says Mr Knight.
His companys solution – a patented system developed to place chemical at the nozzles within seconds of injection – could be fitted to a conventional sprayer to allow the operator to apply chemicals precisely for spot treatments or in variable rates.
"In normal circumstances, for chemical to get to the nozzles all the liquid in front of the chemical has to be sprayed out," says Mr Knight. "The time is lost when low volumes are applied."
The principle behind the Knight system is to constantly circulate liquid through the boom as a closed system and draw on water/base product from the main tank to replace the liquid sprayed out through the nozzles.
With constant circulation taking place, the time taken for an injected chemical to reach the nozzles is very much reduced.
However, many will ask how water is circulated through a boom which has nozzle outlets. The answer is to pump an excess of liquid – more than the nozzles are spraying out – so there is a volume of liquid always returning to the circulation pump for chemical injection purposes.
The key part of the operation is to contain this relatively small volume of circulated liquid as a reservoir, which Mr Knight describes as a virtual tank, for the chemical to be injected into and simultaneously allow the tank water/base product to enter the system.
At this stage of its development, Mr Knight is reluctant to provide the exact details of how this is achieved, but says the pressure of the tank-sourced liquid is higher than that in the circulation system enabling it to enter. *
Chemical injection with minimal delay. Knight Farm Machinerys latest injection system is designed to enable injected chemical reach the nozzles in a matter of seconds.