Calcium reactor design.

[fishboy]

Here's a question for you guys who have made your own calcium reactors.

Is there any reason that the chamber has to be round? You could greatly reduce the cost by making it square (I have lots of left over acrylic).

I was looking at a PM unit and the water enters straight down from the top and exits at the bottom. There didn't seem to be any "swirling" in the chamber that I could notice.

Anyone have any ideas or thoughts on this?

[Aquattro]

Dwayne, I can't see any (real) reason to not make it square.

[DJ88]

I think it is made out of round for ease of manufacture for the most part Dwayne. It's faster to glue flanges to a chamber already assembled than put the chamber together then bond the flanges onto it.
Less room for an error causing wasted materiials.
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[Aquattro]

Darren, I agree. I actually wouldn't want to make it square. Making and sealing the flanges would suck. And if you don't get a perfect cut, you may run into glueing problems. And if you don't mind using extruded tube, the cost is about the same for material.
But, there is no mechanical reason it needs to be round.

[fishboy]

Errors? Wasted material? Ha ha ha. :D That's why I have left over acrylic in the first place.

I don't think making a square flange would be any more difficult that a round flange. Although a round one would be stonger in theory.

I've had very good luck glueing with methalyne chloride. Even with my sloppy cuts. I'm not talking about making a show quality tank. Just something that's hidden from general view and doesn't leak.

How much flow would I need in a reactor with a chamber 4" x 4" x 18"?

[ruck'n'reefer]

I can't remember where i read it but, there are dead spots in a square reactor. Someone should confirm this though.

[DJ88]

Rob,

You'll get dead areas in a round one too.

With the media not being a consistent density throughout the reactor the water will want to find the easiest way to the area of lowest pressure. ie where your pump is sucking water in. The easiest way to do this for the water is to run down the sides of your reactor agasint the acrylic. It is a smooth straight surface for it to run next to. So basically it shouldn't matter too much what shape your reactor is. This is called a skin effect in electronics. I presume it will be a similar effect in this situation. The water woudl rather run on the outside of the tube than the inside de to friction and resistance to flow.

It is this principle that in a high flow effluent situation that makes a second chamber in a reactor useless. If it is a slow flow reactor, say 80 ml/min or so the water will flow somewhat through all the media in the one pass it has in the second chamber. It has more dwell time in the media. But once you start getting the flow rate high enough all the water will want to do is follow the easiest route out of the tube. And that is against the sides of the reactor. Now if you were to add a recirculation pump on that second chamber you'd change that by forcing more of the effluent to run towards the center of the reactor.

I think a square reactor would work juts fine. It's just a heck of a lot easier to work with the round tube than piecing the facets together to make a square one.

In addition the reason it is a good idea to change your media regularly whether you used it all or not and not just "top it up" is that once you start breaking the media down it will form a finer and finer particle size. In time this will form a think paste like clay in your reactor and really affect the flow of effluent through the reactor.

[ 13 May 2002, 22:17: Message edited by: DJ88 ]

[titus]

Hello,

I've considered making the chamber out of flat sheets as well. However, unless you are making say 10 reactors at a time, the manufacturing process shows that it'd cost more for labour and time than to use tubes.

[fishboy]

Titus,

Time's not a factor for me as I want to make it as a diy project(labour's cheap when you work for yourself). I am more concerned with whether it will function properly.