Text 5297, 70 rader
Skriven 2005-01-22 08:41:18 av Robert Bashe (2:2448/44)
   Kommentar till text 5292 av Roy Witt (1:10/22)
Ärende: Tire inflation
======================
Roy Witt wrote to Robert Bashe on Friday January 21 2005 at 09:39:

RB>> That's why air compressors have traps and filters in the lines. That
RB>> kind of stuff doesn't get into tires, at least not in appreciable
RB>> amounts. Incidently, the main problem is compressor oil, but that's
RB>> removed in a trap.

RW> But not all air compressors are equipped with those. Mine for
RW> instance...

But you don't run a filling station. If you did, you'd have commercial
equipment and that always has an oil and water trap. To be honest, I didn't
even know you could buy a compressor without such equipment, since compressed
air straight from the compressor is pretty filthy stuff - has to be, since the
compressor has to be oiled and some of the oil mist always gets into the air.

RW> I use my water filter when I'm using my pneumatic equipment, when I
RW> put air in the tires of my Camaro, but it's not always in the line. I
RW> also use a water filter and a dryer when I'm painting with the air
RW> gun.

Your paint surfaces would look pretty cruddy if you didn't, since any water in
the air would condense when the pressure is removed and the spray cools, giving
blisters in the paint. Unless, of course, you're using a water-borne paint. In
that case, you'd probably have no problems one way or another.

RB>> Oh, and remember another thing: even if you want to put nitrogen into
RB>> a tire, you have to compress it...

RW> I would assume then, that the people who sell it for $5 a tire, will
RW> have all of the water filters and dryers in line with the nitrogen
RW> compressor.

I think that can be assumed.

RW>>> Have the scientist visit a tire shop and have the workers show them
RW>>> the insides of tires when they remove them from the wheel.

RB>> Curiously enough, I've done just that, in fact quite a number of
RB>> times over the years. I'm a scientist with papers to prove it, and
RB>> also have worked on cars enough to know what tires look like, inside
RB>> and out. The rubber dust you often see on the inside when a tire is
RB>> removed from the rim is just due to the abrasion caused by the tire
RB>> constantly flexing under load.

RW> And the rust?

On the bead, you mean? Water from outside, possibly also pulled between the
bead and the rim by capillary force.

RB>> Remember that cold air contains less moisture than warm air.

RW> Not in California.

Always. The laws of physics apply even in California ;-)

RW> Yesterday, during the day with temps in the mid 70s, the humidity was
RW> in the 50-60% range. As the day waned, the humidity began to climb and
RW> was at dew point before midnite with the temps in the low 50s.

You just confirmed what I wrote. The amount of water in the air didn't change
from beginning to end, but when the temperature was higher, the relative
humidity was lower because the air would be able to hold more water. When the
temperature dropped, the air could contain less water and reached its dew point
at some lower temperature.

Cheers, Bob

--- GoldED+/W32 1.1.5-0613
 * Origin: Jabberwocky System - 02363-56073 ISDN/V34 (2:2448/44)