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Forum Index : Other Stuff : Home Made Fertilizer Injector
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casterton Newbie  Joined: 21/10/2015 Location: New ZealandPosts: 10 |
Has anyone made a Fertilizer Injector? My situation is this: I have a 63mm supply line from my well to paddock irrigation, running approx 55psi at the pump, going out to home-build pod irrigaters. My thoughts are this: 1/ Install double brass check valves as back flow prevention. 2/ Beyond this, install a female threaded Tee in the irrigation line. 
3/ Bush this to 15mm. 4/ Install a 15mm tank connector 
I would throw away all the nuts and washers and install this so the male threat goes into the Tee, leaving my the female thread exposed. 5/ On the internal of the Tee, I would attach a 15mm male-female elbow 
This would be left pointing in the direction of the water flow. 6/ Onto the MF Elbow I would have a 15mm female connector 
7/ Lastly on the internal I'd have about 1 mtr of 15mm poly pipe. 8/ External of the Tee, I would have a 15mm male connector 
9/ Install a pipe and tap going to an elevated liquid fertilizer tank. My thoughts are that the tap could be used to regulate the gravity feed of the fertilizer, and that as it's introduced well into the flow on the main line that there should be no back flow issues. Thoughts and comments welcome please. Thanks & Regards, Scott - King Fossic Because I love fossicking!! fos·sick (fŏs′ĭk)/ˈfɒsɪk/ To rummage or search around |
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| jeffj Regular Member  Joined: 04/02/2012 Location: AustraliaPosts: 84 |
It looks to me that you are trying to put a venturi on the pressure side of the pump. I doubt if this will work as there will probably be too much back pressure.For the venturi to work you will need a suction. If you can put it on the suction side of the pump it may work . I do a bit of hydroponics on a much smaller scale. Have a look at the AUTOPOT site they have venturis on their pump sets. I have one and it works well Jeff |
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| casterton Newbie Joined: 21/10/2015 Location: New ZealandPosts: 10 |
Thanks Jeff. This is the first sort of thing like this I've done, so don't know what I'm doing!! (Sometimes that can be good, as you try new things!!!) I as thinking that a raised tank gravity feed would ensure that fertilizer would continue to enter the main water flow? (I wasn't thinking of using the main flow to venturi the fert in). Thanks & Regards, Scott - King Fossic Because I love fossicking!! fos·sick (fŏs′ĭk)/ˈfɒsɪk/ To rummage or search around |
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| jeffj Regular Member Joined: 04/02/2012 Location: AustraliaPosts: 84 |
The problem is that 55 PSI is about 40m head of water You would need to lift the tank to that height which is impractical If you can pressurise the tank it would work, you could possibly use an old oxy acetylene bottle Jeff |
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Downwind Guru  Joined: 09/09/2009 Location: AustraliaPosts: 2333 |
For your raised tank gravity feed to equal 55 PSI you would need the tank raised above surface by 127 feet for the hydrostatic head pressure to equal 55 PSI. Even a venture has its problems for this application, as for a venture to work the exit volume needs to be greater than the flow through the venture. This means your emitter (Sprinkler) system needs to be able to supply more water than the venture can supply, or you will get a back pressure and water will flow out of the venture and not fluid be sucked into the venture as intended. The easy way is to use a pressure cylinder to store the fertilizer and use the pump supply to charge the cylinder with water from the top, and use a supply feed from the cylinder bottom to feed into the sprinkler supply line. I have done this with the cylinders from old water softeners (fiberglass cylinders) or old swimming pool filters also fibreglass. (the old sand filter cylinders) The question is what fertilizer are you adding and in what amounts? I may well be easier to add a small second pump to inject the fertilizer into the water supply. Pete. Sometimes it just works |
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| casterton Newbie Joined: 21/10/2015 Location: New ZealandPosts: 10 |
Thanks for your answers Pete & Jeff. Great explanations of why my gravity system will not work - put simply for easy understanding. Sometimes it's hard to dumb down physics enough for me to understand, but well done to you for doing so. Scott. Thanks & Regards, Scott - King Fossic Because I love fossicking!! fos·sick (fŏs′ĭk)/ˈfɒsɪk/ To rummage or search around |
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Doug Regular Member Joined: 11/05/2010 Location: New ZealandPosts: 41 |
Hey casterton. I've been thinking of doing the same sort of thing in my veg garden. Only I was thinking of adding the fert (liquid) into the water supply before the pump through a T fitting. This would eliminate any back pressure issues as there would be a vacuum whenever the pump was running and flow could be controlled via a small tap. Doug May The Power Be With You |
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rustyrod Senior Member  Joined: 08/11/2014 Location: AustraliaPosts: 121 |
I have a venturi unit that is driven by an ordinary garden hose to suck dirty water from trenches. I suggest you google "Steam Injectors" as for steam locomotives These injectors use the steam from the boiler to take zero pressure water into the boiler On boilers they work from low up to 200 lbs or more. Amazing physics, to use the pressure to inject additional water into the same pressure. I believe the irrigation people already have injectors for your purpose, if only you could pull one to pieces to see how to copy it. Of course you could lash out ($5) and buy one like THIS or similar Appears these will work from 10 lbs to 150 lbs I think there would be DIY articles somewhere on the www Always Thinking |
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