[Stoves] Personal Particulate Monitor

[Norbert Senf]

Andrew:
Yes, I was thinking about this after our previous exchange.
I'd guess there is no fan on your device. It should be easy to check if
there is a flow through the
intake orifice.
It should behave more like a smoke detector - the air has some degree of
"cloudiness"
and it doesn't matter if the air is moving or still.
With a dilute mixture and measurement of individual or cumulative scattered
light "hits" on a
sensor, it is related to particle concentration in the air which is
unchanged by velocity.

For the dilution scheme that I described, I had forgotten about this. You'd
actually need to
add a small fan if you wanted to try this approach, in order to establish a
flow that can be diluted.

Crispin:
Earlier you mentioned a flue gas measurement of 30,000,000 ug/m3 PM in
Ulaanbaatar. That converts to roughly
350 g/kg, or more than 1/3 of your fuel leaving the stack as PM (normalized
to 13% O2), way off the map of anything I
have ever seen or hear of. I'm not really familiar with coal or high fly
ash, so can't hazard a guess - seems almost impossible.

Norbert

Message: 2
> Date: Thu, 13 Sep 2018 09:30:53 +0100
> From: Andrew Heggie <aj.heggie at gmail.com>
> To: Discussion of biomass cooking stoves
>         <stoves at lists.bioenergylists.org>
> Subject: Re: [Stoves] Personal Particulate Monitor
>
> I've made the subject a bit more appropriate, comments below:
>
>
> (snip)
> > I doubt whether the flow speed through it would affect the particle
> concentration, ie if you
> > put a sampling tube on it.
>
> This confuses me somewhat, surely to measure concentration one needs
> to know how much air is passing the sensor and then count the light
> reflected off particles. or is there another way of knowing a
> concentration?  I thought perhaps it assumed the fan drew a fixed
> volume per second and then the reflections were counted and calculated
> as a mass in that volume. If a restriction from a tube reduces the
> flow then a smaller volume passes but the sensor still counts the now
> lesser number of reflections, giving a lower reading??
> >
>

-- 
Norbert Senf
Masonry Stove Builders
25 Brouse Road, RR 5
Shawville Québec J0X 2Y0
819.647.5092
www.heatkit.com
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