I believe in this vintage of the HotCat, the central axis was open to flowing environmental air. That is why the inside of the stainless inner tube would be painted black - to help with radiation from the inside (not that there is very much radiation - only from the ends). The central axis would mostly deliver heat via convection.
The 2 coaxial inner tubes (that appear to be only a single tube) is the only logical place to contain the ingredients. Penon lists the components and there were only 4 observable components. As a welded unit, the central cylinder would appear as a single part - the welded coaxial reactor cell. On Thu, Jul 4, 2013 at 8:05 PM, Jones Beene <jone...@pacbell.net> wrote: > > From: Bob Higgins > > The photo links you supplied appear to be from Fabio Penon's report of 8/7/2012. In this report, he states that this inner tube is stainless steel painted with a "black coating, heat resistant to 1200C". He also says that in this early HotCat, the outer cylinder is painted stainless. > Yes, I agree that these images are not the December HotCat, but OTOH ... > the > main ingredient in black IR coatings is carborundum :-) > > Also, it appears that the inner stainless tube is open to the air (thru) and it is not stated where the ingredients are contained. The paint appears to be to maximize the emissivity.... In this older HotCat I surmise that the inner SS tube may actually be comprised of 2 coaxial tubes with the ingredients between them in a thin layer. > Interesting - why do you think there are two coaxial tubes? What is along > the axis - just a vacuum? > > Then the ends are welded closed (hot or cold welded) and it looks like a single, thick monolithic stainless tube. The Penon report states that the inner tube is painted on the inside and the outside. >
