Pressure or flow - sprayer

[Highashgrange]

What’s the pros and cons of each system?

 

[Robt]

Flow is simple to use and no need to change setting (usually) when changing nozzels. Pressure in my opinion is better as you reduce section via section control.

 

[Highashgrange]

Flow is simple to use and no need to change setting (usually) when changing nozzels. Pressure in my opinion is better as you reduce section via section control.

What about when you set off in a corner. From what I’ve seen flow requires the set forward speed to hit the pressure target which is impossible from a standing start. I’m trying to get away from untidy field corners where herbicides are doing a job and I think it’s the contractors machine.

 

[Robt]

There are setiing such as low speed hold if i remember correctly. So it will maintain say 2 bar at anything below 6kph for instance. Then as soon as you hit 6koh it will start auto regulating.

 

[Steevo]

Flow is simple to use and no need to change setting (usually) when changing nozzels. Pressure in my opinion is better as you reduce section via section control.

I'd agree with you. I prefer flow on the whole but it doesn't work well as lower flow rates.

My RDS controller has "Auto" which in theory runs Flow 90% of the time, and then as you cut down sections and flow rate drops it swaps over to Pressure. Great idea in theory but I'm not sure it's set up as well as it might be because it swaps to pressure, opens the valve, swaps back to flow, shuts the vale, back to pressure, etc etc. ad infinitum.

 

[Bumble Bee]

If you go for a pressure based system, I'd advise fitting ceramic nozzles. Nozzle wear will quickly throw a pressure based system out of calibration.
Pressure based is great for high volume jobs where a flow meter cannot handle the wide variation in flow.

 

[cosmagedon]

I had a pressure based Berthoud DP tronic that was fantastic, I've now got a RDS 34i working on flow and finding it hard to get used to in comparison.

The pressure system was very accurate, you could set a start off pressure that it held for X amount of seconds until you got a chance to get up to speed, this was brilliant in corners or awkward fields.

 

[Al R]

What about when you set off in a corner. From what I’ve seen flow requires the set forward speed to hit the pressure target which is impossible from a standing start. I’m trying to get away from untidy field corners where herbicides are doing a job and I think it’s the contractors machine.

As you reverse in the corners, for the last 2-3 metres turn the nozzle’s on so they spray as your going backwards and as you go forwards again.

 

[jg123]

What about when you set off in a corner. From what I’ve seen flow requires the set forward speed to hit the pressure target which is impossible from a standing start. I’m trying to get away from untidy field corners where herbicides are doing a job and I think it’s the contractors machine.

I just hit manual as I approach corner, when I pull off its holding the rate of say 9kph then I hit auto as I hit 8 or 9k as im leaving the corner. Do the same if I'm crossing very bad ruts etc so it's putting on a heavier rate rather than loose my pattern when going very slow

 

[robbie]

I just hit manual as I approach corner, when I pull off its holding the rate of say 9kph then I hit auto as I hit 8 or 9k as im leaving the corner. Do the same if I'm crossing very bad ruts etc so it's putting on a heavier rate rather than loose my pattern when going very slow

That's exactly what I do
I also flick into manual for headland turns. I switch to Manual before switching off and only engage auto again once I've switched on again. I find in manual it'll switch the Bo's in instantly at the correct pressure but in auto it takes a while to get to where it needs to be and by then your a few yard up the field, this is on a flow based system.

 

[Clive]

am in correct in recalling the horsch machines uses both pressure and flow together ?

 

[jg123]

That's exactly what I do
I also flick into manual for headland turns. I switch to Manual before switching off and only engage auto again once I've switched on again. I find in manual it'll switch the Bo's in instantly at the correct pressure but in auto it takes a while to get to where it needs to be and by then your a few yard up the field, this is on a flow based system.

I do that if I'm turning 2 or 3 sections off if I'm hitting the headland at an angle, otherwise for some reason pressure drops then it corrects but you've sprayed 40ft by the time it corrects.

 

[Matt L]

am in correct in recalling the horsch machines uses both pressure and flow together ?

Yes you are. They work using both to be as accurate as possible.

 

[Wombat]

Most decent controllers should be able to switch between flow and pressure on the go depending On settings. I prefer pressure control for normal spraying

 

[warksfarmer]

As you reverse in the corners, for the last 2-3 metres turn the nozzle’s on so they spray as your going backwards and as you go forwards again.

All that does is loose the pressure already held because you can’t reverse backwards at 10km/hr which is the set spraying speed to get the correct pressure matched to the nozzles.

 

[Lincsman]

Mine seems to take long enough to respond to setting off from the corner to not matter, there may be a setting in there somewhere?

 

[DrWazzock]

For years after my controller died I just left it a fixed 3 barg and driove at a fixed 10k. Setting off out of corners I press the foot switch and by the time pressure and flow has rebuilt in the lines I’m back up to 10k.
Now using a berthoud dp tronic with auto pressure regulation with speed. Min pressure stop 2 barg so can get out of corners with a decent pattern as dose. Seems ok.

 

[Robt]

Mine seems to take long enough to respond to setting off from the corner to not matter, there may be a setting in there somewhere?

Yes you can adjust how quick it reacts to speed change. Set it too high and it will jump up and down. Set it too low and it will be as you say. Set it just right and you sir are a spraying god!!!!