That's identical to the one I used, but bigger. I think I soldered mine directly onto a 15mm pipe (being careful the solder didn't run into the sintering) but I may have turned the thread down on the lathe to fit. It does protrude into the tank about 6" .. I don't think bubbles travelling up the processor wall would be as effective. However, like I said before, I have a gut feeling that the sintered silencer isn't the way to go ... I recon a sparge pipe might be better.
I've just had a play in the garage and found a very easy way of putting really tiny holes into 15mm pipe. Many years ago I was given a small quantity of very sharp, very finely tapered, very hard steel pins. They were used for constructing wiring harnesses or looms. I never understood why they couldn't simply use nails, but the guy who gave them to me made electrical control cabinets for a living and said they were the best things to use.
Anyhow using one as a punch puts an incredibly small hole through the wall of 15mm copper. Looking at the depth the pin penetrates and measuring the taper at that point I recon the holes are about 0.6mm. I have vague recollections that they were called layout pins in the trade, but I can't find anything on them with a quick Google. HCII might know what they are called or they could be made from silver steel on a bench grinder and hardened afterwards. If you can wait I can give you one (a pin that is) at Chugs.
I can't find one on ebay, but if you go for a needle valve, this is the sort of thing to look for ...
http://www.swagelok.com/search/find_products_home.aspx?show_results=Y&item=42e66d92-14ca-497c-9246-d6922ca2a4c3 but cheaper!
If you are ONLY dewatering oil or bio, you don't really need a needle valve, you can use quite a high volume of air perhaps controlled by a gate valve if needs be. I know you want a condenser to give an indication of when the oil's dry, but during the drying process it's of little consequence if you vent excess moisture to atmosphere, the condenser will still show you when no more water is being driven off.
