180 gallon build: Modular control system, 3D printed equipment, open-source
- Thread starter jrhupp
- Start date
Colin at MakerFarm was helpful for me in the beginning. He got me over some stupid rookie misunderstandings of how things should work. (I should add too that his reputation for support is part of why I originally choose my kit).
Otherwise, lots of reading on the net. No place in specific. Just google and lots of sorting through superstition and fact.
Small update for the moment. Most projects have been on hold as I focus efforts on a printable skimmer design. Below is an image of the SketchUp model showing a partially complete skimmer and an exploded view of the printed parts. I think the first pass at the design is more or less good to go; there are few dimensions that need to be tweaked to improve fit, but what is there is workable as is.
Since early last week the printer has been running like mad cranking out parts as I get them modeled up. I have not tracked print time very closely, but in total it is upward of 90 hours. And I am happy to say that as of the wee hours of this morning all parts are printed! Now I'm in the midst of doing some clean up and pre-assembly before vapor polishing. Once that is done I will start cutting the acrylic and getting this guy together (hopefully over the weekend).
I think the design incorporates some nice features, though time will tell how well they perform or what use they are. If nothing else, they should make the design quite tunable/tweakable. Which is a feature often lacking in DIY skimmers.
- Water depth in the skimmer is set by an adjustable riser on the out flow rather than a valve that restricts out flow.
- The venturi is modular and inserts inside the intake tube to the pump (as opposed to a venturi that is more or less a fitting glued into the intake). It is held in with a threaded nut at the base of the air intake. So it is easy to remove for service or to swap out for an alternative design.
- The air intake/muffler is adjustable and comes apart for service.
- The tapered neck leading to the collection cup is threaded and screws on to the skimmer body. With it removed there is full access to the inside of the skimmer.
- The bubble diffusor plate threads into the skimmer. So it too can be removed for service or swapped out should I want to try alternative designs.
Once it is complete I will put up a video showing disassembly, which should make it clear how it all goes together and what is adjustable. I will also put together something showing performance. It is yet to be seen how it will perform, but that is what testing is for. The current plan is to test out the gate with the stock impeller on the DCT-4000. Pending those results I will look at options for a printable needle wheel. I am guessing the needle wheel will be needed, but as the stock impeller looks to be press fit on the ceramic shaft I am hesitant to attempt disassembly without a confirmed need.
Since early last week the printer has been running like mad cranking out parts as I get them modeled up. I have not tracked print time very closely, but in total it is upward of 90 hours. And I am happy to say that as of the wee hours of this morning all parts are printed! Now I'm in the midst of doing some clean up and pre-assembly before vapor polishing. Once that is done I will start cutting the acrylic and getting this guy together (hopefully over the weekend).
I think the design incorporates some nice features, though time will tell how well they perform or what use they are. If nothing else, they should make the design quite tunable/tweakable. Which is a feature often lacking in DIY skimmers.
- Water depth in the skimmer is set by an adjustable riser on the out flow rather than a valve that restricts out flow.
- The venturi is modular and inserts inside the intake tube to the pump (as opposed to a venturi that is more or less a fitting glued into the intake). It is held in with a threaded nut at the base of the air intake. So it is easy to remove for service or to swap out for an alternative design.
- The air intake/muffler is adjustable and comes apart for service.
- The tapered neck leading to the collection cup is threaded and screws on to the skimmer body. With it removed there is full access to the inside of the skimmer.
- The bubble diffusor plate threads into the skimmer. So it too can be removed for service or swapped out should I want to try alternative designs.
Once it is complete I will put up a video showing disassembly, which should make it clear how it all goes together and what is adjustable. I will also put together something showing performance. It is yet to be seen how it will perform, but that is what testing is for. The current plan is to test out the gate with the stock impeller on the DCT-4000. Pending those results I will look at options for a printable needle wheel. I am guessing the needle wheel will be needed, but as the stock impeller looks to be press fit on the ceramic shaft I am hesitant to attempt disassembly without a confirmed need.
Parts are all printed and the skimmer is assembled. Here are all the parts printed from the model posted above and vapor polished, prior to final assembly.
Assembly went well enough. I used weldon-16 to bond the acrylic tube to the printed parts, and man is that stuff a pain. I got too much on the bottom of the collection cup; so it could be prettier but is good enough. Below is a video showing me taking apart the completed skimmer where possible (fair warning, I only have two hands: one for the iphone and one for taking the skimmer apart). I dropped the printed venturi in favor of an airline at the inlet to the pump; performance was about the same with less noise and less flow restriction. So win win. I also dropped the stock impeller for the DCT-4000.
<iframe width="640" height="360" src="https://www.youtube.com/embed/Ssyq8iwvkRc" frameborder="0" allowfullscreen></iframe>
Here are the potential replacements for the stock impeller. On the right is the first version. The second version is on the left. Not the cleanest prints but on par for what my printer does with tiny parts (I have not optimized retraction for these kind of prints). Functionally I don't think either are optimal yet, but performance is not too bad.
Here is the second version in action. This is tap water, after dipping the tip of a soapy finger in it.
<iframe width="560" height="315" src="https://www.youtube.com/embed/W-Ft4mJqmHU" frameborder="0" allowfullscreen></iframe>
The skimmer is temporarily setup on the tank as of this evening. I need to clean up a few plumbing items for the full install and will post a few pics after that is done.
We shall see how it starts performing after the break in.
Assembly went well enough. I used weldon-16 to bond the acrylic tube to the printed parts, and man is that stuff a pain. I got too much on the bottom of the collection cup; so it could be prettier but is good enough. Below is a video showing me taking apart the completed skimmer where possible (fair warning, I only have two hands: one for the iphone and one for taking the skimmer apart). I dropped the printed venturi in favor of an airline at the inlet to the pump; performance was about the same with less noise and less flow restriction. So win win. I also dropped the stock impeller for the DCT-4000.
<iframe width="640" height="360" src="https://www.youtube.com/embed/Ssyq8iwvkRc" frameborder="0" allowfullscreen></iframe>
Here are the potential replacements for the stock impeller. On the right is the first version. The second version is on the left. Not the cleanest prints but on par for what my printer does with tiny parts (I have not optimized retraction for these kind of prints). Functionally I don't think either are optimal yet, but performance is not too bad.
Here is the second version in action. This is tap water, after dipping the tip of a soapy finger in it.
<iframe width="560" height="315" src="https://www.youtube.com/embed/W-Ft4mJqmHU" frameborder="0" allowfullscreen></iframe>
The skimmer is temporarily setup on the tank as of this evening. I need to clean up a few plumbing items for the full install and will post a few pics after that is done.
We shall see how it starts performing after the break in.
From what I have read there seems to be two schools of thought on this; either more turbulence in the skimmer body or less turbulence. The first follows the logic that more turbulence forces the bubbles to take a longer path through the body allowing for more contact time. The second says that with increased turbulence bubbles collide with each other and break up. If they are already loaded with organics, that is counter productive to skimming. Most modern skimmers seem to follow the later thinking.
I could be tempted to argue that the swirl I have was an attempt to strike a balance between the two schools of thought. But that would be me BS'ing you.
In practice it was a combination of a bit over site and not having a good handle on the physics of the bubble plate as that is where I intend to control flow dynamics in the main body. I'm not thrilled with the degree of swirl and will be revising the plate to deal with it. I have a few thoughts on this and hope to print up a second version and test it this week.
BigDave
Premium Member
Agreed!
Gorgok
New member
I assume then you will be doing some sort of stator on the bottom of the plate. That could work nicely just have to keep in mind you don't want to take all the force in the first few fins or the last ones will be useless. Then theres the how much and in what direction... Is there a computer simulation for fluids that can handle microbubbles?
Not sure on the simulation software. Thats a bit beyond me.
As to the stator, maybe. I'm starting with a design that simply has a longer path through the plate and have tweaked size and distribution of the holes. I'll see how this goes and refine from there.
I printed the part off today. But have not had the opportunity to get it in the skimmer.
Not as of yet. So far just ABS. But I have tester roll of some flexible filament that I hope to get too trying out over the holidays.
Thanks!
Anytime... after the holidays.
Regarding the skimmer, have you tried other methods? Since you can pretty much make anything ( 
) it would be interesting to buy a venturi from Life Reef and use that. Then just a matter of deciding on the neck height, width, to fix and customize.
While personally never using a bubble type plate skimmer and being partial to venturi's was just wondering the choice. I like the overall idea and some of the possibilities.
) it would be interesting to buy a venturi from Life Reef and use that. Then just a matter of deciding on the neck height, width, to fix and customize.While personally never using a bubble type plate skimmer and being partial to venturi's was just wondering the choice. I like the overall idea and some of the possibilities.
