I need help with a cap for an acrylic reactor tube

[minibowmatt]

Im making a nano-sized phosban/carbon reactor. I have 2" ID tubing, 15" long. I have the base, and screening figured out, but i need to design a cap that I can remove easily for refilling, but yet will stand up to 100-150GPH.
I also am trying to figure out how put the water in to the tube. I want the water to flow up from the bottom, to do this I have a .5" acrylic tube going through the center of the reactor. I have pics but I cant post them till my laptop is fixed... (having new motherboard installed as we speak)
Im looking for easy (HD parts) solutions. I dont want to order anything...
Thanx!

 

[Anonymous]

If the reactor is acrylic, it is best to get one of the flunge set for the cap, otherwise, you need to find a good way to attach a PVC threaded cap to a acylic tube.

For the 1/2 inch tubing that goes to the bottom, I usually just drill and tap a hole for a 1/2 FPT (female pipe thread) on it, and get a JACO or JohnGuest adoptor for it.

 

[minibowmatt]

flange kit? can you point me to what your refferring to? I am looking into a barbed fitting on the end of the inner .5" tube. The issue is, how to get the cap to attach to the tube. Maybe the flange is the best way..
can I make one of these? or is it something I need to buy?

here are some pics:
the top section of the reactor tube

here is the whole thing (dry fitted)

 

[minibowmatt]

sorry about the huge pics!

 

[Anonymous]

I see that you already have a barb adaptor for the 2 inch tube. You can use the same adaptor for the 1/2 inch tube, or just use a dremel to "barb" the end of it for a vinyl tubing to go over ("barbing" means to cut some channels out of the 1/2 inch tubing so that the soft vinyl tubing can gripe on it).

As to your main concern, there are typically done in three ways. 1, use all PVC part so that you can get the threaded cap in hardware store. 2, use PVC on acrylic tubing and hope that the bond is strong enough to hold. 3, use pre-fab flange kit people use for calcium reactor.

Seeing there is a tube coming out of the top, and the small size of your cylinder, it is going to be a difficult thing to do. My suggestion is to fabricate a "twist-lock" type of mechanism out of acrylic and use O-rings to seal the inner and outer tube. It is not going to be easy if you want to keep the design that you have.

 

[minibowmatt]

seven ephors-- Thanx for the comments.
The design is negotiable. I thought having the 1/2" tube coming out of the top would be useful so I could then just remove the cap and pull the 'cartridge' out for emptying/refilling. Well It is time to go home now.. I'll be working on this more tomorrow..

 

[Anonymous]

Just some random comment, aka my 2 cents.

I would move the 1/2 inch tube to go in from the bottom to simplify the top design. You just put some short legs (3/4 inch tall) on the bottom, and bent the 1/2 inch tube to a L or a J. This way, you have more choice as to how you can do about the top cap.

 

[minibowmatt]

I was thinking the same thing. It would be much easier to put the inlet and outlet on opposite ends of the tube.
I was thinking just use another hosebarb in the other end... like this..

 

[Anonymous]

Yep, that will work. Lay it up vertically if you want a bottom-to-top flow for better perculation. If I were you, I would look into a PVC threaded cap with hose barb and see if you can find a female-threaded PVC pipe with around 2 inch inside diameter and see if you can find some epoxy/cement/glue that can attach the PVC to acrylic nicely.

 

[minibowmatt]

I decided to go with the flange idea. I found a couple big O-Rings here at work, and I am just going to chuck a 4.25" acrylic square in my lathe, and put a groove in it to accept the O-Ring. then I just need to attach the flange to the tube with weldon.

 

[Anonymous]

That will certainly look better than the PVC idea.

 

[minibowmatt]

well I got it put together today. I found a 2.5" X3/16" O-ring, and used that as my flange gasket. It is all glued together, and I will water test it tonight with FW. Im a little worried about one joint, I see airbubbles and I had to move it after I applied the Weldon3. It was still gooey when I moved it, and i re-applied more weldon after it was positioned correctly. I will post pics tonight sometime.

 

[Anonymous]

If I caught a bad joint early enough, I usually take it apart and wait until it it dried, then sand the edges slightly, and rejoint them again. Sometime you can fix a bad joint afterward with a syringe with thin solvant and let the capillary do the work.

I usually use a bicycle pump and put in 10 PSI of pressure, close the reactor, and submerge it underwater to check for air bubbles or check for pressure drop after a few hours. Air came out a lot faster than water.

 

[minibowmatt]

Thats a great idea-- using the pump. I have a compressor so I will do that. I did a quck water test and it was leaking at the joint i was worried about. have to fix it....

 

[Anonymous]

Careful with a compressor if the volume of the system you are testing is small (such as this case). The pressure can go up so fast that the compressor can damage it. I usually use a bike pump.

 

[wetworx101]

You can use a PVC union and cap it off.

 

[minibowmatt]

here are some pics of the finished unit. I have water tested it, and it is now leak free.

I need to buy filter media, and then I will hook it up to the tank...

 

[Anonymous]

Looks good! 8)

So how did you do the top tube? any diagram or photo that you can show us?

 

[minibowmatt]

I did the top by turning a 3/16" groove in the flange on the lathe. I used a round nose cutter to create a shallow rounded groove about 1/16" deep. I did a matched groove on the top piece of the flange. I removed the center of the bottom flange, and glued it right to the 2" tube. I then drilled four holes in both flanges to accept the nylon bolts. I also cut a 5/8" hole in the top flange to allow the 1/2" tube to penetrate into the chamber, and then glued it in place for a watertight seal. now when you remove the lid, it pulls out the center tube, and diffuser disks like a cartridge.
here is a link to all my pics...:
http://www.reefbucket.com/browse.php?ac ... %20Reactor

 

[Anonymous]

Your link ask for a passwd...

Since you glue the 1/2 inner tube to the top flange, it can be a bit messy whenever you need to change the media, don't you think?