Another Sprayer Re-build

[Iplayfarmer]

Auctions are my new hobby. I picked up the carcass of an old 30 gallon spray rig with a boom a few weeks ago, and I want to re-build it into a 3 point PTO sprayer. It came with a belt drive pump that I'm going to try to convert to 540 PTO. I think I can get the adapters I need from Surplus Center.

What I need right now is advice on setting up the pressure circuit. Is there some kind of valve that I can get that allows the sprayer to come on and off, but keep the PTO running all the time? I picture something with a pressure valve that will bypass the excess flow back to the tank when the spray nozzles are shut off.

 

[Berniep]

Auctions are my new hobby. I picked up the carcass of an old 30 gallon spray rig with a boom a few weeks ago, and I want to re-build it into a 3 point PTO sprayer. It came with a belt drive pump that I'm going to try to convert to 540 PTO. I think I can get the adapters I need from Surplus Center.

What I need right now is advice on setting up the pressure circuit. Is there some kind of valve that I can get that allows the sprayer to come on and off, but keep the PTO running all the time? I picture something with a pressure valve that will bypass the excess flow back to the tank when the spray nozzles are shut off.

Yes there are a couple of valve that you can get to manage the flow of fluid.
One will set pressure and bypass back to the tank.
Something like this
The other can be plumbed to control different circuits to the boom so you can control one side or the other and or set to recirculate.
something like this
The 3point rigs that I have seen use both.

 

[JRP]

This might not apply to your system, but...

Be careful with belt drive pumps. If it is a centrifugal pump with an impeller, which is very good design, it is designed to run at an engineered speed range which is usually much faster than 540 rpm. Usually they run about 3600 rpm. If you direct couple this to your pto you might get several psi output pressure.

pto driven centrifugal pumps use a speed increase belt drive so the pump runs faster than the pto.

The faster you operate a centrifugal pump, the higher the pressure.

 

[Iplayfarmer]

This might not apply to your system, but...

Be careful with belt drive pumps. If it is a centrifugal pump with an impeller, which is very good design, it is designed to run at an engineered speed range which is usually much faster than 540 rpm. Usually they run about 3600 rpm. If you direct couple this to your pto you might get several psi output pressure.

pto driven centrifugal pumps use a speed increase belt drive so the pump runs faster than the pto.

The faster you operate a centrifugal pump, the higher the pressure.

Thanks for the info. I was actually just digging through my pile of junk from a more recent auction and found a gearbox that may work. It has a keyed shaft input and a pulley output that turns a lot faster than the pulley. I counted 17:1 turning the shaft by hand. I may rig it like that. I'd have to run at a lower engine RPM and use a larger pulley on the pump, but for free I'll try my best to make it work.