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How to Build a Sprayer

Discussion in 'Pesticide & Herbicide Application' started by p3tris, Sep 6, 2009.

  1. p3tris

    p3tris LawnSite Member
    from Cyprus
    Posts: 8

    Hi guys, it's nice to find your community here (even if i'm from half the way around the world).

    While at a friend's house i saw he had a "Homemade" sprayer. It consisted of a container (it must have been 60-80 ltrs) an electric pump and really long hose with a spray gun at the end. The Hose must have been 25-30m long. The whole installation was immobile under a shed in the garden.

    I like the idea! For my garden i need approx 320 liters to cover the premises. I have a 20 liters backpack sprayer, but as you can calculate that means more than 16 refills and my back hurts in the end. My friend says he inherited the sprayer from the previous owner, so he cannot help me.

    What i want is some guidelines to the sizing of the whole thing. How big the container? What kind of a pump? The diameter of the hose? what kind of spray gun? What should i look for? (pressure, length of the hose-longer=better)

    I am a licensed electrical engineer (so the pump and the electrical installation won't be a problem) and i have no problem "making things".

    I'm willing to take pictures if this project takes of and post them back here at the end.

    Thanks!
     
  2. greendoctor

    greendoctor LawnSite Fanatic
    Posts: 8,802

    My first question is why do you need to apply 320 liters to cover your property? How high up do you need to spray and at what volume? Long hoses are not necessarily the best thing. A long hose causes you to lose pressure and volume at the end, especially if the hose has a small bore. If it were just my property that I had to spray, I would look at an engine drive knapsack sprayer or an engine drive sprayer on a cart. The knapsack sprayers usually hold 25 liters, operate at 25 bar pressure and discharge up to 8 liter per minute. A sprayer on a cart holds up to 100 liter and has a similar rate of discharge. I am in the business of treating lawns and trees. For most uses, an engine drive knapsack has proven to be very handy. There is no long hose to get tangled or snagged. Hoses are also very good at ripping plants out of the ground. So I do not care for them in many of the landscapes I maintain.

    If you really want a stationary spray unit. What you need is a pump capable of at least 20 bar pressure, over 4 liter per minute output and hose with a 10MM bore. It is hard to say how long the hose should be. The spray gun used depends on what you are trying to treat. Dense shrubs and low growing flowers are best handled by a different gun from what is used to spray tall trees. I know I keep one gun for tall trees, one for lawns, and one for shrubs and low flowers. They are very different in operation and appearance from each other.
     
  3. p3tris

    p3tris LawnSite Member
    from Cyprus
    Posts: 8

    Hi, thanks for answering so quickly! I calculated the 320 litres. I have knapsack sprayer with 20 ltrs capacity and on average i need to refill it 15-16 times (with the appropriate mixture of course) to spray everything in the garden. I have olive trees, lemon trees, a tangerine tree, 2 vines (which i have grown into sheds. Meaning i grew them 3m tall and then used them to cover a piece of land), peach trees. Also i have many other trees that i don't know their names (in English). The trees are on average 2.5-3 meters tall (and thus cannot easily be ripped out from the ground by the hose).

    The knapsack sprayer has the problem of having to refill and do the mixture 15-16 times to cover the whole garden and going forth and back for the refills! The cart has the problem that my garden is in horizontal levels, each level separated from the next with 4-5 steps. Taking a cart with an 80-100 liters tank up and down those stairs would kill me :weightlifter:

    The stationary spray unit i thought would be great because my house is situated in the middle of the garden and i believe with a hose of 25-30 meters long i could spray everything.
     
  4. greendoctor

    greendoctor LawnSite Fanatic
    Posts: 8,802

    Seeing your situation described in detail, this is the one time a centrally located spray system makes sense. The reason why a hand operated knapsack sprayer uses so much liquid is its low pressure and consequent poor coverage. The average hand sprayer is only good for 2-3 bar and that is if you are really pumping. Way too much effort. I think a 150 liter tank, a 15-25 bar pump and 30 M of hose with a variable pattern gun would do well for you. Does it have to be electric? Electric pumps have limits on volume and pressure unless you are talking about a belt or direct drive triplex pump and a big motor to operate it. Japan has engineered some great pump engine units that could well be used stationary, even though they are designed to be portable. They also would cost less than an equivalent electric drive triplex pump. Have a look at these http://www.maruyama-us.com/uploaded...ecification_Sheets/NPOWERSPRAYERS-COMPACT.pdf http://www.maruyama-us.com/uploaded...Specification_Sheets/08POWERSPRAYERS-SETS.pdf
     
  5. Ric

    Ric LawnSite Fanatic
    Posts: 11,946

    p3tris

    I will suggest the below link as a possible 12 V pump for a home made unit. I have several of these pumps on different set ups and they work fine for me.

    http://www.tractorsupply.com/agricu...m-pump-with-demand-switch-and-harness-2111954

    I power these pumps from both my truck battery and a Small rechargeable Gel Battery to make them portable. I have 2 different sets ups that push a 300 ft hose (100 Meters approx) from 25 gallon tanks (100 Liters Approx). For portability I also have a 2 wheeled Golf Bag cart that I converted with a Gel Battery and a 5 Gallon (20 Liter Approx) Jug as a tank. I use one of those 20 ft (6 meter approx) Curly Que hoses that stretches on the Golf Bag cart.

    Remember just like electric wire, Hose has resistances. The longer the hose the more resistances and the lower the PSI and GPM.
     
  6. Falcon50EX

    Falcon50EX LawnSite Senior Member
    from GA
    Posts: 999

    Ric, would you post some pictures of you setups. I have a 20gal tank that I would like to put on a dolly and pull around.

    Thanks for any info:usflag:
     
  7. Falcon50EX

    Falcon50EX LawnSite Senior Member
    from GA
    Posts: 999

    Have not seen that pump setup how much? Most backpacks are around 500$ you can build one for half that.
     
  8. Ric

    Ric LawnSite Fanatic
    Posts: 11,946

    Falcon

    Sorry no Camera. I keep my Pull around unit to 5 gal and under because of weight. Even at 5 Gallon in thick thatch it can be a Pain. Any thing Bigger should be pulled by a Tractor of some kind IMHO. I use Blue Gas jugs and can change them out To shoot different products or Cocktails of Herbicides. I use this unit mostly for spot treatment but it works well for blanket treatments as well.

    BTW I pick up Golf Bag dollies from Garage sales for $ 2.00. Actually my neighbor does it for me since I don't garage sale shop. I got the Idea from the same neighbor who uses a 3 gallon pump up sprayer on his around the house. Here in God's Waiting Room we try and work smart not hard.
     
  9. Falcon50EX

    Falcon50EX LawnSite Senior Member
    from GA
    Posts: 999

    Ric, I have read a lot of your post and very good info Thanks from a new guy on the block. It is my first year in business I still need to find reasonable cost insurance for my little operation.

    Thanks
     
  10. p3tris

    p3tris LawnSite Member
    from Cyprus
    Posts: 8

    Hey Ric, thanks for the reply.

    Will this setup have enough juice to spray a 2,5-3m tree through a 30m long hose? Because the best electric (12V) pump i found tops at 90 PSI (~6.2 bar). If you can post some more details of your setup (what kind of hose? 3/8''?) a picture maybe?

    Also what does "with Demand Switch and Harness" means? Is it vital? :p

    (because i live outside US and sometimes is hard to find what i want...)

    thanks!
     
    Last edited: Sep 6, 2009

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