12V Sprayer pump flow and pressure question

[dhermesc]

I bought a little tow behind John Deere sprayer. It has a 30 gallon barrel and 6' of booms (4 or 5 spray nozzels total) and a hand boom. It came with a 3 HP gas engine and a belt driven pump. Seller says the pump is ruined - looks like its 50 years old and cracked. Rather than mess with engine, I decided I would just get an electric pump and plump it in. What kind of flow and pressure should I get for this to work? I was thinking something along the lines of 1.5 gallons per minute with 40 PSI. Is that balance correct or should I go bigger?

 

[wh]

I bought a little tow behind John Deere sprayer. It has a 30 gallon barrel and 6' of booms (4 or 5 spray nozzels total) and a hand boom. It came with a 3 HP gas engine and a belt driven pump. Seller says the pump is ruined - looks like its 50 years old and cracked. Rather than mess with engine, I decided I would just get an electric pump and plump it in. What kind of flow and pressure should I get for this to work? I was thinking something along the lines of 1.5 gallons per minute with 40 PSI. Is that balance correct or should I go bigger?

I would splurge for higher volume. At least in the 2 1/2 gallon minute range.

 

[Goose]

I'm with wh. We have pull behind sprayors with 25, 40, and 60 gallon tanks, and I'd say go at least 2 1/2 gpm.

 

[WESnIL]

Match your pump output with the total nozzle needs. To reduce drift you want higher volume nozzles for medium to large droplet size. That requires volume which equates to higher gallons per minute. If using TeeJet flat fan nozzles (my preference) that translates to .6 gpm per nozzle minimum. My memory from my spraying days says a nominal 4 gpm pump for satisfactory performance. 5 nozzles @ .6 gpm equates to a 3 gallon per minute pump, leaving nothing for recirculation. Pressures in the 30 to 40 psi range are adequate. Increase the pressure and you decrease droplet size and increase drift. As with tractors (There is no substitute for horsepower.) in spraying there is no shortcut or substitute for volume.

 

[Tgrasher]

I mounted a 15 gal tank with a 3 gpm 12 v pump and 5 nozzle boom on my zero turn mower and it works great. Rigged a on/off rocker switch to mount on the right side handle.

 

[RobCons]

I would cheat and look at some of the store bought models of similar size and go from there.

 

[Destroked 450]

I have a 10 gallon spot sprayer with just the hand wand, it has a 1 or 1.5 gpm pump
My 20 gallon sprayer with 3 nozzle boomless spray bar has a 4 gpm pump, I can partially open the recirculating valve to control pressure on that one, I don’t thing that would be possible with a 3 gpm pump, definitely not with anything smaller

 

[Geo-TH,In]

I bought a little tow behind John Deere sprayer. It has a 30 gallon barrel and 6' of booms (4 or 5 spray nozzels total) and a hand boom. It came with a 3 HP gas engine and a belt driven pump. Seller says the pump is ruined - looks like its 50 years old and cracked. Rather than mess with engine, I decided I would just get an electric pump and plump it in. What kind of flow and pressure should I get for this to work? I was thinking something along the lines of 1.5 gallons per minute with 40 PSI. Is that balance correct or should I go bigger?

I have a 25 gallon pull behind 12v sprayer.
I use water only and spray my driveway. I adjust pressure and nozzle height to get good coverage.
Then I experiment with how many oz of Roundup I use per gallon and see how long it takes to kill the weeds in my driveway.
Usually 5 gallons will do all my driveways.
I use between 2 to 3 oz of Roundup per gallon to get weed kill I like.
I want to use as little pressure as possible. I don't want a mist blowing in the wind, Larger droplets works for me.

 

[wh]

I would splurge for higher volume. At least in the 2 1/2 gallon minute range.

I have a 2.5 gal minute pump running 5 tee jet nozzles on boom spraying trails and roadways on farm. Using 8002 nozzles. Get great coverage. Have plenty of pressure.

 

[Texasmark]

Your 40 PSI should do it if not overkill. I keep my spray pressure below 30 to ensure droplets (that resist drifting) rather than a mist......also on the drifting, spray when wind is dormant and I spray upwind.....wind in my face...but since you are repairing an existing sprayer, you knew that.