Sprayer Regulating pressure on PTO Sprayer?

[Champy]

I was looking for a way to replace (avoid) using the 4 gal backpack sprayer for applying Roundup around my trees, and bought a used 3ph mounted 55gal tank with included hoses and roller pump at a local farm auction.

Now once I get everything repaired, hooked up and working.....how do you regulate the line pressure to the spray wand? By rpm? You don't need to?

Thanks

 

[jjmarotz]

3/4 PRESSURE VALVE BRASS - Agri Supply
and
PRESSURE GAUGES - Agri Supply

This is what is most commonly used. Good luck.

 

[Champy]

So perhaps a more basic followup question......do I really need to regulate the pressure? I am assuming this how you adjust the volume of spray applied...but don't know for sure if this is a must-have or a want-to have. Thanks

 

[Farmwithjunk]

A typical pto/3-point sprayer has a built in regulator to adjust system pressure that finally flows to the spray nozzles on the boom. While using the boom, normally you would turn off a hand valve that cuts flow/pressure to the wand. When using a hand held wand, simply valve off the boom, open the valve to the wand, and use the same system pressure regulator to adjust psi through the wand. Adjusting flow/volume via changing speeds of the pump would be erratic and inconsistant for the most part.

Excess pressure is vented from the regulator back into the tank. That flow is used to keep the tank agitated.

Under "normal conditions", I generally apply most spray @ 50psi.

 

[radman1]

So perhaps a more basic followup question......do I really need to regulate the pressure? I am assuming this how you adjust the volume of spray applied...but don't know for sure if this is a must-have or a want-to have. Thanks

With a pto roller pump, you will need to regulate the pressure or you will get to much pressure and something will blow. The pressure gauge will tell you where to set the pressure valve. You could do without the gauge and go "by gut feeling" on how much pressure you have. The gauges are not very expensive and I have seen plastic pressure valves which are fairly cheap.
Start by opening up the pressure valve all the way. Then turn the handle until the pressure increases. I tend to use 40-60 lbs of pressure. You can turn it up to 100 psi if using a hose and jet nozzle but that is pretty high. The pressure gauge will let the excess fluid bypass back into the tank.

 

[chh]

You can spray quite a long distance with my hand gun at 100 psi. I got to playing with my new sprayer this spring and tried it with the pressure cranked up. The boom buster spray nozzles on mine for weed spraying recommend 20 to 50 psi. The hand gun works fine at that pressure. My hand gun came plumbed to be pressurized anytime the main control valve is on. My control valve has a recirculate position to mix the tank and that is the setting I use when using the hand gun.
My only complaint with my rig is that my guage goes to 300 psi. It has the fewest pressure markings from 0 to 50 psi where you need the most accuracy with the nozzles I use . I will probably change out my guage next year before I start spraying.

 

[EastTexFrank]

The only thing I would add is that the higher the pressure, the smaller the droplets and the more likely the spray is to "drift" if there is any breeze. From the replies it seems that I run mine at a slightly lower pressure than most, 40 psi.

 

[teg]

I have mine calibrated at 25 psi for 12 gallons per acre and I get good coverage without chemical driping off the plants (waste). I don't have heavy (thick) brush... If I did, I would change to higher pressure (& more GPA) for better coverage. I try and spray the least amount I can but still have it work.

 

[john_bud]

Plumb in a T with one leg to the spray attachments (bar or wand) with a gage on the attachment side, the other leg back to the tank. Add a stainless steel ball valve on the return leg. Turn ball valve to adjust bypass. More bypass = lower pressure to attachment.