Chip Krout wrote:
>I'm certain that this "weekend paint purge" process worked well and is
>probably still used today by auto companies...but...I'm not sure I'd want to
>get the first car off the paint line on Monday morning with a little extra
>thinner in the lines!!??
Ah, it was a bit more sophisticated than that.
Process went something like this:
1. Pressurise system with cleaning solution (thinners) and operate all spray
guns until
all trace of colour had vanished from nozzles. At periodic intervals, certain
feed
circuits to guns were blocked off in rotation to ensure thorough cleaning in
all lines.
2. Purge system of solution with compressed air and ensure all spray nozzles
left open
until Sunday night with air running through them. During this process, all
gratings and
trolley tracks were removed, sandblasted and re-installed.
3. On Sunday night, the colour for first paint process on Monday morning was
linked to the
system and heated/agitated to ensure thorough mixing. On Monday morning prior
to track
starting, each nozzle was operated in turn until a continuous paint flow came
out of it.
Only then was the track started. As colour was changed, say from red to blue,
the blue
supply was connected to the system, pressurised and the simple hydraulic effect
in the
paint lines brought the colour out to the nozzles.
Dave Massey has asked me to recount a story I told him when he was in England
last summer.
It was told to me by the foreman of the paintshop cleaning team.
Underneath the paintshop. there was a rabbit warren of narrow corridors and air
suction
pipes. The purpose for these 'rat runs' was to suction thinners and explosive
gases out of
the paint area and ovens, through air scrubbers and venting to atmosphere. In
one of these
underground areas, there was a small 'control centre' with instruments and
gauges
measuring the amount of airborne contaminant. As the area of highest pollution
was in the
first 50 feet of the beginning of the high bake oven, this was where thinners
fall-out was
at its highest. The heat of the ovens also came down the system with the
contaminants and
this all helped to keep the man who worked there warm in the winter. In the
summer, his
lack of clothing just about kept him decent - but visitors never went in that
area.
One winter's night, after the night shift was over and there was a very heavy
air frost,
the man in the rabbit warren was cold.
In the wee small hours, clouds of smoke were seen to be coming from what were
by now
comprehensively blocked scrubber filter outlets and the fire brigades from the
factory and
from Coventry Main were called with what can best be described as a degree of
urgency. On
descending to the depths of the earth, expecting a 'flashover' or something
worse, the
fire teams found a new employee sitting at a rusting half oil drum in which
holes had been
made with a pickaxe. The 'stove' was filled with wet coke (modified form of
coal) and this
was smoking heavily. Nonetheless, there was sufficient heat at the base of the
container
to make toast - and this is what he was doing. The foreman who told me this
story was at
pains to point out that the questions fired at the person concerned was not "I
say old
chap, what are you doing?" It was a little more pointed and no-one could
understand why
there had not been an explosion. Had it not been for a very convenient draught
of clean
air that passed across the floor and around the base of the fire, there would
have been
one big BANG.
Jonmac
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