Demco sprayer

[MikeinKy]

I recently bought a 600 gal. Demco sprayer at an auction. It has a centrifugal pump and a ground drive pump. Why would it have both? i don't know why it would need the ground drive. I got a manual with it and it just explains about the ground drive, don't mention the PTO pump.
 

[IaGary]

PTO is mose likely for tank agitation.

Ground pump is plumbed to the boom and the other to the tank.

Gary
 

[MikeinKy]

Wouldn't the centrifugal pump be enough for it to work? I would think it would pump a lot of water.
 

[JD Seller]

Mikein Ky you don't understand what you have bought. The PTO centrifugal pump is to agitate the spray solution while you are setting still. The ground drive pump meters the amount you want per acre within a speed range. So if you slow down or speed up the gallons per acre stays the same. The pressure and flow changes to match your ground speed. You have to go fast enough to make the nozzles work and slow enough that the flow does not max out. Usually a range between 3-10 MPH.

If you have a regular sprayer that you have to spray at a certain speed and pressure. You put more gallons per acre on when you slow down and fewer gallons per acre when you speed up.

The ground drive pump is a better system if it is working correctly. The PTO pump should just be for agitation only. Which is good as well because the spray solution will be kept mixed better. Some regular sprayer pumps do not have enough flow to agitate much when you are spraying.
 

[MikeinKy]

Thanks for the replies. I thought that was the way it was supposed to work. You are right about the amount applied. I sometimes waste a lot with a pto pump. Maybe it is set up this way for better accuracy. I wanted one like this for awhile. usually they go for 3000 to $5000 around here. I got this at auction for $1000 wit 600 gal tank tandem axles, 45 ft boom and foam markers.