# DIY Air Driven Dosing Pump.



## GHNelson (6 Feb 2011)

Hi gang@ukaps.
Ive been toying with the above idea for a while...........to dose my 36 litre Arc Tank.

Components needed.
1 Lock and Seal 1.9 Litre canister.
1 Air pump.
I sponge filter air uplift tube.
2 Bulkhead 6mm push-fit connectors.
4 3/4 inch rubber washers.
1 Piece of 12mm/16mm tubing.
Airline/Co2 tubing.
Non return valve.
Air line regulator.

Here is a how I perceive making the dosing pump/canister.
1 Mark the top of the canister for drilling.Drill 2 holes.




2 Attach the washers to the bulkheads and screw to lid .It would be better to use silicone also, but I didn't. 



3 Affix the 12mm/16mm tubing to one of the Bulkheads and uplift pipe...... soften with hot water to make attaching easier.
  Add the softflex Co2 tubing to the other bulkhead and the uplift pipe as photo.



4 Add your Fertilizer close the lid....... push fit the tubing with a check valve added to the air in hose and a small air regulator valve.The black tubing is the out tube where the fertilizer is dosed from.





5 Switch on the pump






6 Trialing it on my moss.



 
Although this idea may need tweaking for your own use the concept is good....running it on a timer would be best.
(I haven't tried that yet).But I have switched the power on and off to the air pump and it works okay.
Regards
hoggie


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## LondonDragon (6 Feb 2011)

Interesting idea, where do you buy all the bits and how much does it all cost? Cheers


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## GHNelson (6 Feb 2011)

Hi
I sourced the bulkheads from here
http://www.altecweb.com/home.asp?cat=Subcategory14810
The food canister was from Robert Dyas or you could get a similar one from Wilkinson's although its square.
Also the rubber washers are from Wilkinsons plumbers section.
The Sponge filter was from Ebay.
The cost..........
Bulkheads               £7.00 approx
Food Canister         £2.50
Rubber washers         .79p
I already had the rest of the other pieces So about £10.00.
Regards
hoggie


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## a1Matt (6 Feb 2011)

I'm impressed. Great idea and simple professional looking implementation.  Subscribed


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## GHNelson (6 Feb 2011)

Cheers Matt  
Works a treat at level height...
I don't think there will be a problem below the aquarium.
I may modify it a bit later so watch this space.
Cheers 
hoggie


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## Ed Seeley (6 Feb 2011)

I love the idea but as the level of fert drops in the container then surely the amount being lifted out by the air is going to reduce as the head increases?

As it's an air tight container couldn't you have just pumped air in the top and used the higher pressure to squeeze the liquid out of the tube.  

Also how do you control the amount dispensed?


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## GHNelson (6 Feb 2011)

Hi Ed
That's not the case its the air in the uplift chamber that lifts the liquid and forces it up the tubing.
The amount dispensed can be tweaked or controlled by the air valve.
Or by the timer the longer its on the more ferts it doses obviously.
I did think of using the method you stated but i think you would need a hell of a lot of air pressure to move the water up the tubing.Remember we only want to dose a small amount of liquid 10ml to 25ml.Say  twice in 15 minute bursts.
The Macro can be diluted to co-inside with the length of time the timer is switched on.
Ive got a inkling that if the uplift chamber is full of water it may syphon the canister in to the aquarium if both are at level height. 
I will have a go at the method you stated and report my findings.
Cheers for the input.
hoggie


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## Ed Seeley (7 Feb 2011)

Let us know how you get on.  The way I suggested might not work.

Your current set up seems to be working in the same way as an air uplift though so as the liquid level in the container drops the head will increase reducing the flow rate.


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## GHNelson (8 Feb 2011)

Hi Ed  
The system you suggested does work in practise and theory...but there is a few hurdles to overcome.
1 The holes cut into the top of the canister/container must have a good seal and no splits or there is air leakage.
2  You need a precise needle valve to regulate the flow of air.
3 A check valve is needed near the end of dosing line to stop back flow.
4 The higher the dosing line the more air pressure required.

Remedies for the above.
1 Silicone seal the joints.
2 Use a Air pump with a regulator....this would help some what.
3 Add a check valve 
4 Dose straight into the out  tube of the filter.

I have a small split where i drilled one of the holes so there is air leakage ...i tried silconing it but no joy.
I will purchase another canister and be more careful when drilling....
So its back to the drawing board...... more up dates tomorrow.
Cheers
hoggie


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## a1Matt (8 Feb 2011)

This might seem a bit slapdash, but I have found blu tac can give a good airtight seal.
I would not use it on a permanent installation, but if you have some to hand might be a good rough and ready solution when testing.


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## GHNelson (8 Feb 2011)

Hi Matt
Thanks for the tip.
I will post some more pictures tomorrow.
hoggie


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## GHNelson (10 Feb 2011)

Hi gang
I purchased a new container and drilled new holes........... the vessel is air tight now.
I had a go at the method Edd suggested without the airlift chamber. Only in and out tubes.
Photo 


It works a treat at level height but when i raise the dosing tube to the height of the aquarium level the pressure falls.
So no liquid....I tried using a plastic check valve to stop the back flow but this was not such a good idea as their only usually for air/co2 ........not liquid.I have another idea to over come this problem.I think.
Here a few Photos of the Air driven dosing pump working.















I also have another idea on the airlift chamber but this will have to wait until i get the part....next week.
This needs modified or botched   
This will be my last hope of trying to get the liquid up into the aquarium. :?: 
I suppose I could try a massive air pump but the defeats the purpose....and i haven't got one.

There is just one other alternative run the dosing tube into the external filters out pipe at approx the same height side by side I like this method best but....I need a connection similar to the Boyu in-line atomiser. 
Back to the  :arrow: drawing board.
Cheers hoggie


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