Alex, Paul, One option is to use a suction pyrometer in which you pull the hot gas past the thermocouple in a tube. The tube limits the radiation so you get a better picture of the true temperature. Temperatures can be about 90C (200F) higher in the suction pyrometer than in a boiler or free air. A simple version can be made with compressed air venture drawing air through a pipe with a thermocouple inside it.
Tom -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Alex English Sent: Wednesday, March 14, 2012 6:18 PM To: Discussion of biomass cooking stoves Subject: Re: [Stoves] radiant heat capture, total heat measurement Paul, So this makes sense. The screen radiates away heat leaving a cooler gas beyond. If your thermocouple were smaller or shielded the difference would likely be even greater because the thermocouple looses more heat from radiation when it is hotter. Or are there other reasons, too? Alex On 14/03/2012 7:36 PM, Paul Olivier wrote: > There are problems with what I have written below. > Let me again. > > Without the dome, the probe encounters hot gases and registers a > temperature of 563 C. > It turns red hot and starts emitting thermal radiation. > > With the dome, the probe encounter hot gases as well as thermal radiation. > But it only registers a temperature of 500 C. > It does not turn red hot. > Therefore the probe does not absorb thermal radiation from the dome > very well. > > Thanks. > Paul > _______________________________________________ Stoves mailing list to Send a Message to the list, use the email address [email protected] to UNSUBSCRIBE or Change your List Settings use the web page http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists .org for more Biomass Cooking Stoves, News and Information see our web site: http://www.bioenergylists.org/ _______________________________________________ Stoves mailing list to Send a Message to the list, use the email address [email protected] to UNSUBSCRIBE or Change your List Settings use the web page http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org for more Biomass Cooking Stoves, News and Information see our web site: http://www.bioenergylists.org/
