Re: [CAD_CAM_EDM_DRO] Re: Air mist coolant

Having spent a lifetime in intimate contact with air conditioning systems I
too would be very wary of any mist cooling systems. The problem isn't that
quantity of liquid floating about in the air but the tiny droplet size and
the smaller the droplet, the more the danger.
This was the problem which, of course, gave rise to Legionnaires disease
where the air in an hotel air conditioning system was humidified by passing
it through water sprays. The small droplets so entrained in the air remain
suspended there for a long time and are breathed into the very smallest
vessels in the lungs. In a machine mist coolant system the problem ares
are:-
1. All water is likely to contain the bug which causes Legionnaires disease
(Legionella pneumophila) - it is very common in all but borehole water and
is VERY resistant to attempts to kill it. However, it is only dangerous if
inhaled.
2. Unless the coolant contains an effective biolcide directed specifically
at Legionella, the bug is unlikely to be killed. Such effective biocides
have their own toxicity problems - they are based on either Chlorine or
Phenols and work by rapidly oxidising the bacteria (burning them to death).
3. Normal 'nuisance' masks will either not stop the finest mist passing
through or will become waterlogged quickly. With a system where a fine mist
is being bounced off work at high pressures, the only sensible protection
would be a full-face respirator - not much fun to work in .
Of course, if the machine is in a properly designed, hermetically sealed
cabinet with filtered extract ventilation and interlocks on the doors to
ensure all mist is dispersed before the doors open........

Ian
--
Ian W. Wright
Sheffield UK
www.iw63.freeserve.co.uk

----- Original Message -----
From: "ron ginger" <ronginger@...>
To: <CAD_CAM_EDM_DRO@egroups.com>
Sent: 19 January 2001 23:16
Subject: [CAD_CAM_EDM_DRO] Re: Air mist coolant


> Dan Mauch said:
>
> >I am very wary or the mist coolant systems because of
> >possible health concerns so I decided to add a flood
> >coolant system back on my full size Enco mill.
>
> Have you actually seen a good air mist in operation? A friend of mine
> runs a Bijur on his CNC mill. If you hold your finger in front of the
> mist stream it takes a couple seconds before a whole DROP of liquid