Wasserpests Fluidoser

[Wasserpest]

A couple of months ago I started playing around with some designs for a device that allows me to dose small amounts of concentrated liquids, like Flourish and Flourish Iron.

While my powerhead dosing works great, it two disadvantages: the mixtures degrade somewhat over time, and (therefore) need to be replaced/refilled regularly.

So I spent quite a bit of time and parts to figure out a simple, cheap, reliable and repeatable design for this "Fluidoser" It is still not 100% finished, but I have 4 or 5 of them running (dry, but fine so far).

Here is a step-by-step instruction if you want to try one or a few of these.

First, here is what we need:



- a mechanical timer
- some syringes (more about that later)
- plastic wire clamps the size of the syringes
- a couple of screws (I use #4-40 x 1/2")
- two check valves for each doser
- some plastic T's
- zip ties
- something to attach to the timer to hold the syringe (I use paint stirrers from HD)
- a little piece of drip irrigation hose or some sort of washers
- (not shown) some airhose, I am going to use the "mini" kind to reduce the amount of fluid remaining in the hose

Okay, now that we have everything, we need some basic tools:

- screwdriver for the screws
- drill with drill bit ( I needed a 3/32" for the screws I used)
- if you have a Dremel it helps to shape the paint stirrer

I guess that's it for now. Here is what we do:

1) Drill some holes into the rotating part of the timer. The more distance to the center, the larger will be the amount of fluid dosed. You need only one hole really, but since you are at it add some more in case you want to adjust the dosing later. Right after drilling a hole I screw a screw into it, carefully... if you do that gently, you won't need any nuts, as you are cutting a thread into the plastic.

2) Cut a piece off the paint stirrer (or whatever you choose) and shape it so it can be attached to the timer. Drill two holes through it, then through the timer, and attach with screws. See 1) about the screwing part.
I haven't done that for the smallest of my syringes, but I probably will. I attached the smallest one directly to the timer, however, the tilting point is so close to the rotating part of the timer that the top of the syringe moves around quite a bit throughout the day, therefore you'd need a little longer, flexible airhoses.

3) Take the plunger out of the syringe, and, with a hot knife, burn two tiny holes into the end part to pull through a zip tie, which then attaches to the screw on the rotating part of the timer. While you are looking at the plunger, give the rubber seal a nice massage with silicone lubricant. This will make the movement smoother, easier on the plunger and timer.

4) Drill a hole into the wooden extension, where the clamps with the syringe goes. I am using a piece of irrigation tube as a washer to lift the clamp up a little, so the plunger can move freely and parallel to the syringe.
As for the position of the hole, you need to see that the syringe is completely closed (no liquid in it) with each rotation of the timer. The clamp should grab the syringe towards the top, where the needle would go, to reduce the movement of the syringe.

That's pretty much it, wow, only 4 steps... Screw it all together and see how much the plunger moves (how much liquid is moved each day)





Regarding the syringes: I have a small one that doses up to 0.5 ml daily, one up to 3 ml, and one up to 6 ml (which I am not going to need for my tanks). The small one will be dosing Flourish and Flourish Iron in my 10gal tank, 0.4 ml daily*, there will be one ml of the mixture going into my 36gal, and 2 ml daily into my 100gal tank. Once it works perfectly I might dose PO4 the same way, with a second timer per tank.

* Please note that I mentioned these numbers just as an example... everyone doses differently.

[Brilliant]

What no trademark?
Man thats genius! Thank you for sharing this really looks awesome.

[bharada]

Do you intend to make a dual overhead cam model in the near future?

Seriously though, this is very ingeneous. I wonder how many cycles the plungers will be good for?

[Wasserpest]

You know, that's not that far-fetched. I thought about a double doser... but haven't figured that one out yet. I definitely want to keep dosing K and N via powerhead, which doubles as an evaporation top-off. Leaving P out of the macro solution might help to extend its lifespan...

Lifespan of the plungers... good question. Time will tell. The small syringes are really thought for one-time use, so it will be interesting to watch them.

One nice thing is that due to the slow movement of the timer and the two check valves there isn't much chance for big spills.

[hooha]

very neat, but won't you have to fill these up pretty regularly? Can it be done using a 50cc syringe?

[Brilliant]

Originally Posted by hooha

very neat, but won't you have to fill these up pretty regularly? Can it be done using a 50cc syringe?

They fill themselves. There is a reservior of fertilizer you dont see in the picture that the tube is inserted into.

When the dial spins the syringe sucks and blows....at 2am it sucks and at 12pm it blows. Welll sorta just to give you an idea...im sure it sucks all night and then blows all day. But you get the idea...right?

Sorry if it not my place to answer this question.

[bharada]

With the disposable syringes I'd be more concerned with how long before they fail to pull a vacuum and end up not drawing any fluid into them.

I used to work for Eppendorf (many years ago) assembling mechanical pipettes. Our test fixture used custom made glass syringes which had plungers fitted with replaceable quad-rings. The rings were grease daily and replaced monthly (or whenever CVs started getting consistantly out of whack).

But I'm sure you're not interested in using syringes that run in the hundreds of dollars each.

[Wasserpest]

Originally Posted by Brilliant

When the dial spins the syringe sucks and blows....at 2am it sucks and at 12pm it blows. Welll sorta just to give you an idea...im sure it sucks all night and then blows all day. But you get the idea...right?

Sorry if it not my place to answer this question.

Brilliant explanation, and thanks for pitching in! I guess it isn't that obvious how it works. Yes, the "In" side of the not-shown vinyl tubing will go into a bottle of Flourish for hopefully many months of automatic blowing and sucking, uhm, dosing.

[Wasserpest]

Originally Posted by bharada

With the disposable syringes I'd be more concerned with how long before they fail to pull a vacuum and end up not drawing any fluid into them.

I used to work for Eppendorf (many years ago) assembling mechanical pipettes. Our test fixture used custom made glass syringes which had plungers fitted with replaceable quad-rings. The rings were grease daily and replaced monthly (or whenever CVs started getting consistantly out of whack).

But I'm sure you're not interested in using syringes that run in the hundreds of dollars each.

Nah, saving money is my trade The syringes cost $0.30 or so each, replacing them won't be a big issue.

Greasing the rubber rings is a good idea... maybe not daily, but perhaps every other month or so. If this turns out to be short lived (I don't expect it to be) I will look into a DIY dosing pump with a santoprene hose.

[exmt]

WP, this is sweet. I need to try some of this stuff!

Do you think that the timer motors can take this kind of load 24/7? I'm sure there's some wear involved.

Also, does the dial spin at the same rate with a load than without it? It would be great to have a dual doser/timer!

Regards,
Tony

[Wasserpest]

Don't worry about the timer motor. It is actually quite strong, I managed to almost shear off one of those little plastic nipples that some timers use just because it got stuck somewhere. I am more concerned about the plunger bending or breaking when the rubber gasket dries out and doesn't move as well anymore.

I am planning to use them as timers too... Again, I don't think it would be a problem for the motor. You can see that I removed the "timer function" from the unit pictured on the left, but it isn't necessary.

(BTW... If you use the timer that I pictured, and a wooden extension like I used, you need to open up the timer and remove the blue override wheel, really easy to do.)

[RobChuck]

When the dial spins the syringe sucks and blows....at 2am it sucks and at 12pm it blows. Welll sorta just to give you an idea...im sure it sucks all night and then blows all day.

I don't remember the exact quote, but this line reminds me of the Flowbee bit from Wayne's World.

Wasserpest,
This is a great device! I look forward to reading about the long-term viability of your "Fluidoser".

[tazcrash69]

Hey Wasser, great thread, and great innovation. I may try this for my nano.

Also to quote Wayne's World again:

"We're not worthy, we're not Worthy".

[exmt]

I took a look at the Dutch pages again. The other form, http://www.home.zonnet.nl/rsetteur/a...dex_doseer.htm
seems to be a diy peristaltic pump. This one has no parts to wear out (ie, plungers, gaskets), practically solving your part wear problem.

The link above says this model doses about 0.75mL per 24 hr period, just enough for micros.

If the flow rate is excessive, one can place an airline valve inline to restrict flow, as backpressure has no effect on the peristaltic pump design. If you tried restricting the flow of the plunger-type pump, it would be a disaster.

What do you think about the diy peristaltic? A go or no-go?

Regards,
Tony

[Wasserpest]

Hehe, what's with all the Waynes World quotes??

Exmt, the big advantage I see with this syringe design over the peristaltic pump is that it is adjustable in a very precise way.

The link above says this model doses about 0.75mL per 24 hr period, just enough for micros.

This statement doesn't make much sense to me. There are big differences between a 10gal and a 100gal tank, high light vs low light etc. Looks like they are dosing KNO3... must be a pretty concentrated solution.
And no parts to wear out? I would think the hose itself would be a big issue. As it gets older, dries out, doesn't squish as easily... Although regular silicone hose isn't too expensive either.