Hi The other answer is to let the temperature control electronics take care of the problem. If you are doing something inside that uses energy (like an oscillator) it have generate a heat rise through the insulation.
Bob Sent from my iPhone On Nov 26, 2010, at 2:24 AM, "beale" <be...@bealecorner.com> wrote: > In an attempt to educate myself about temperature stability, I put a > temperature sensor in a 1" cube of brass wrapped in plastic packing-type > bubble wrap, and compared that with another sensor outside the bubble wrap, > with the whole combination in a thin nylon case just to slow down direct air > drafts. I put it on the bench in the office where the ambient temperature > varies up and down by a few degrees over the day. I recorded both > temperatures with milli-degree resolution. > > Looking at the resulting plots, it looks like my thermal mass and thermal > insulation on the "inside" sensor gives me only about a half hour lag at > most relative to the "outside" sensor (hard to say exactly, it doesn't look > like a simple one-pole filter). Note, I am not attempting any kind of > ovenized control as yet, just measuring some time constants. > > I've read that plain bubble wrap has an "R value" of about 2 > ft^2·°F·h/(BTU·in), while some types of rigid foam building insulation go up > to R=8 (at least until the CFC gases used to blow the foam leak out). What is > done in real instruments that need good thermal insulation? I assume dewar > flasks are limited to aerospace applications. > > Photo of the block prior to bubble wrap: > http://picasaweb.google.com/bealevideo/2010_11_18TempExperiment > > (live) plot of temperatures: > http://www.pachube.com/feeds/12988 > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
