Willie,
I was not suggesting that your method was not good enough, but merely
pointing out that one of the reasons for differences in the VDO readings and
those of the Raytek could be due to measuring different things. The VDO
readings may, in fact, be "spot on," but you won't know using the infrared
technique.
Chuck
> ----------
> From: William G. Lamb, III[SMTP:lambroving@worldnet.att.net]
> Reply To: William G. Lamb, III
> Sent: Thursday, September 23, 1999 8:57 PM
> To: Vandergraaf, Chuck
> Cc: Morgan Mailing List
> Subject: RE: Cooling
>
>
> Chuck,
>
> Most certainly your solution would be best, but far too much
> trouble for Willie. The friend who conducted this experiment with
> the measuring of top and bottom of the radiator for me used to
> do it with a thermocouple as you suggested, but found the
> diviation to be no greater than +/- 1 degree C. whenever he did
> inside his shop at ~ 75 F. In this particular application he no longer
> bothers to use the thermocouple. Unless MMC radiators are
> made of Martian alloy, this degree of error is acceptable to
> me. As a matter of interest, he reports a much larger error
> with an oil cooler of say +/- 5 C. This could be due to a lower
> rate of flow or any number of other variables. "Close enough for
> Government Work", as they say.
>
> Regards,
>
> Willie
>
> At 08:02 PM 9/23/99 -0400, Vandergraaf, Chuck wrote:
> >Willie,
> >
> >This is a bit academic for me, since my +4 hasn't been fired up for years
> >(it has to wait until I get around to restoring it), but the measurements
> >you had done interest me anyway. You say that you had the "water
> >temperature measured ... with a Raytek infrared gun." Unless the sensor
> >actually "saw" the water (in which case I have no argument, but wonder
> about
> >the actual setup), would the sensor not have measured the surface
> >temperature at the two locations? If so, the temperature drop across the
> >thickness of the walls has to be taken into consideration and a 10 - 14 C
> >drop may well be possible (depending, of course, on the ambient
> >temperature). The actual water temperature may therefore well have been
> >higher than what was measured. I would think that, to check the
> calibration
> >of the VDO gauge, one would have to place thermocouples at the same
> >locations as the VDO sensors and compare the readings.
> >
> >Am I missing something?
> >
> >Chuck Vandergraaf
> >'52 +4
> >Pinawa, MB
>
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