Technically - it could either use pressure or flow to achieve rate control, but you are correct that a rate controller will control rate. [emoji1][emoji1]
Technically, you could not increase one without increasing the other. (Unless flow was so low that there was both liquid and air able to pass through the nozzle orifice together)
One could increase flow by increasing internal bore of the pipe whilst keeping pressure the same or even restrict flow by decreasing the internal bore of the pipe what the pressure remains the same.
No - it's not measuring pressure so therefore it can't change it. As far as the flow based rate controller is concerned it's changing flow. The by product of it changing the flow is that the pressure will change (unless there is a bypass or PRV).
I think you will find the flow based rate controller measures the flow, compares it to the speed and adjusts the pressure accordingly. This adjustment of pressure is achieved by opening or closing the bypass valve which sends mix back to the recirculation.
It's usually one or the other not both together. Pressure sensing for very high flow rates.
Any constant rate controller should do that. I am not familiar with the hardi machine but any controller has to be programmed correctly. So you need to make sure the nozzle spacing and boom section configuration is entered as well as the working width.
