Foam Fractionation - Riser tube materials. What's Best?

[stugray]

I have always been curious if anyone has done any experimentation on different types of materials of riser tubes in skimmers.

I know there is a difference in materials as far as surface tension & various liquids.
Some liquid/material combinations form a concave meniscus ( water in pyrex ) while other combinations form a convex meniscus ( mercury in pyrex ).

I am sure that the foam head formation and expulsion of the foam to the cup is a function of interaction between the foam & the riser tube.
This has to be, in some way, related to surface tension of the liquid. However in our case the foam is more complex than a simple liquid.


Anyway, my skimmer has a removable riser tube, so that I can experiment with lengths.
I chose to use some tube that I had laying around that I think is polyethylene ( PVC glue wont stick to it ), and it does well. It slides perfectly inside my 3" PVC coupling:

Coincidently, the funnel I chose for the dome looks like the same material.

Just curious about other's experiments with different materials.

Anyone tried Teflon???



Stu

 

[Malifluous]

Siliconization can change he properties of any material.
Plastics and glass are immersed or the siliconization liquid is wiped on then allowed to dry. I have never tried this with my skimmer cup but your thread has inspired me to do so. I have used siliconization with lab equipment to prevent microorganism growth .
I found this explanation on google... sounds like it would be perfect for skimmer cups.
It further minimizes the interactions between the product and container.

It prevents high viscosity products from sticking to the internal surface of the vials giving the glass bottle a prefect transparency.

Finally, due to its hydrophobic properties, the silicone coating ensures a higher restitution rate down to the last drop of the product.

 

[stugray]

Malifluous,

How do you apply the silicone? It must be very thin ( low viscosity ) to be able to apply it in a uniform coating.

I dont know if you planned on posting a link above, I would like to read more.

Stu

 

[Malifluous]

Here is the product. Is is called aquasil. It is nothing like the silicone we use to seal aquariums. It has viscosity like water.
http://www.fishersci.com/wps/portal...ut=true&brCategoryId=null&hlpi=y&fromSearch=Y

Basically, The surfaces are cleaned with detergent and dried. Aquasil is diluted in Acetone. The dilution is then wiped on the surface to be treated. IME and easier way is to dip the surfaces to be treated into the diluted aquasil.
The surfaces are then dipped in ethanol to stop the siliconization and allowed to dry overnight or in an oven for 15 minutes.

I guess it is not really practical for most aquarist. I have some at work. I will try it on my collection cup and post the results.

I have some at work. I will try it on my collection cup and report the results

 

[Valab]

Silane-izing should have about the same effect as putting a teflon coating on the plastic. Not sure what good it will do in the collection cup, but I've always thought that a non-stick riser tube would be a good thing. I haven't tried to make one yet.

Definitely not practical for most aquarist and the acetone would dissolve PVC and acrylic, but looking forward to hearing your analysis with the polyethylene (or polypropylene).

 

[stugray]

Valab,

I was originally speaking about the riser tube & dome assembly of the skimmer.

Malifluous stated "I will try it on my collection cup" and I assumed he meant riser.

The website above states the aquasil product as:

"AqualSil* Siliconizing Fluid
Application: Attaches the silane polymer, octadecyltrialkoxysilane, to make the surface inert or can polymerize to create an inert film, Water-dispersable, Usable on plastic surfaces, Great resistance to base hydrolysis

CH3 (CH2)16CH2Si(OR) 3"


Malifluous,

If I sent you a section of 6" pipe, can you treat it with your experiment?

Stu

 

[Malifluous]

Yes of course I was speaking about the riser tube. Valab has a good point, Acetone will destroy acrylic and pvc . I believe it can be dissolved in methanol or ethanol as well. There is another product called surfasil that we use for glassware.
Stu I can treat some pipe for you. What is the pipe made out of? I can try a sample of the material u are planning to use and see what happens.

 

[stugray]

Malifluous,

I am not positive what the material is, but purple PVC glue did not dent it. I am guessing polypropylene.... Same as some of your kitchen utensils ( funnels, meas. cups, etc )

PM me some contact info & I'll send you a short piece just to try.

I will actually be in Fl. end of this year for a while ( Cape C./Titusville )

Stu