OT: Re: [Rockhounds] Hi Temp Moisture Sensor

[Kreigh Tomaszewski]

A quick Google search turned up...


http://www.ingentaconnect.com/content/els/09254005/1995/00000025/ 
00000001/art85155

Abstract:

A high-temperature humidity sensor for use in ambient atmospheres has  
been developed, the first in industry, using a limiting-current  
zirconia solid-electrolyte planar oxygen sensor. We have now developed  
a multisensor capable of measuring both the humidity and oxygen content  
simultaneously by further improving the features of the planar  
electrode configuration of this high-temperature humidity sensor. In  
considering the application of this sensor to direct firing or  
combustion systems, we have investigated the individual effects of  
concentration of O2, CO2, CO, and Noitx upon the water vapor pressure  
measurements. As a result, we find that the oxygen concentration has  
the most effect, and also that, in parallel with theoretical studies,  
approximately correct water vapor pressure measurements can be obtained  
when the data are compensated with respect to the oxygen concentration.  
We shall also report the effects of CO2, CO, and NOitx, We verify that  
practical high-temperature humidity sensors can be realized for use in  
direct firing systems by using this multisensor.

...
I also note from my search that lumber kilns use microwave based  
moisture sensors that don't have to be inside the kiln -- they only  
need a window into the kiln or exhaust stack. Perhaps one of them could  
be adapted.

Kreigh



On Monday, Jul 7, 2008, at 14:17 America/Detroit, Gary Brown wrote:

> Not rockhound... But there sure a bunch of clever folks here.
>
> One of my glass buddies is looking for a moisture sensor that will  
> operate
> inside of a 2000F kiln.  Here's the application:  she creates molds  
> out of a
> plaster/silica/gunk mix that contains water.  She's got that inside a  
> kiln
> along with a load of glass that will eventually fill the kiln.  An
> electronic controller controls (what else would a controller do, eh?)  
> the
> time & temperature of the kiln.  In this case, she wants to heat the  
> kiln
> and have it sit at, say, 1000F until the moisture in the mold bakes  
> out.
> When that happens, the moisture in the air inside the kiln should drop.
> When that drop occurs the kiln resumes heating up to the full melt
> temperature.
>
> The fly in the ointment is finding a moisture sensor that can survive  
> 2000F.
> Any suggestions?
>
> GcB
>
> -- 
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