Nitrogen (again)

#11

All compressor have driers that remove the water precipitated by the heat of
compression, when proper maintained. LOL

"Tegger" <invalid (AT) invalid (DOT) inv> wrote

Quote:

dr_jeff <utz (AT) msu (DOT) edu> wrote in
news:_pKdnZ3BAMbVEUbXnZ2dnUVZ_vednZ2d (AT) giganews (DOT) com:

Mike Hunter wrote:
As someone said the air inside the tire, as well as the air OUTSIDE
of the tire, is already nearly 80% nitrogen.

Air has something that nitrogen doesn't have: water. Water can
condense or evaporate, causing changes in the pressure of the tire
faster with air than with nitrogen.

But you can get water-free air. That's what the FAA specifies for aircraft
tires when nitrogen is not available.

Any garage with a drier on their compressor can provide water-free air.
Dry
air is what any garage /should/ have, because it prolongs the life of air
tools and helps keeps them from spitting oily goop all over the place.

However, the difference is pretty small; IMHO, not worth the extra
cost. (Note: If you're a NASCAR crew chief, please disregard what I
said. The differences are important for NASCAR cars.)

And for aircraft, whose tires may need to go from -100F to 100F in an
hour.

Nitrogen, for road-going passenger cars, is a nice frill (especially with
those funky green valve caps), but far from essential for safety or
anything else.

--
Tegger

#12

Have you ever seen a commercial air compressor, that discharges the
compressed air from the bottom of the accumulator tank? Compressors
normally have an automatic water discharge valve on the bottom of the
accumulator tank.

"Tegger" <invalid (AT) invalid (DOT) inv> wrote

Quote:

dr_jeff <utz (AT) msu (DOT) edu> wrote in
news:yq-dnafQ09q5B0bXnZ2dnUVZ_hCdnZ2d (AT) giganews (DOT) com:

I suspect that an air drier provides air with reduced water rather
than no water. So with an air dryer, there still is some water left in
the air. Unless you're a NASCAR driver or crew chief, probably not
enough to make a difference.

The FAA seems to think the same.

And even "pure" nitrogen is never purer than about 95%, which is all
commercial nitrogen generators are capable of making.

However, a lot of gas stations have air
hoses with small compressors that provide the air. I doubt that the
small compressors have air driers on them. Nor do the small pumps that
are plugged into the 12-V power ports in cars.

That's true, but those little compressors don't generally have large
reservoirs that accumulate big puddles of water that could make their way
into tires (or air tools).

--
Tegger

#13

Thanks for the insight, dr. I hope the connection valve differs from the
oxygen connection valve.

"dr_jeff" <utz (AT) msu (DOT) edu> wrote

Quote:

Tegger wrote:
dr_jeff <utz (AT) msu (DOT) edu> wrote in
news:yq-dnafQ09q5B0bXnZ2dnUVZ_hCdnZ2d (AT) giganews (DOT) com:
I suspect that an air drier provides air with reduced water rather
than no water. So with an air dryer, there still is some water left in
the air. Unless you're a NASCAR driver or crew chief, probably not
enough to make a difference.

The FAA seems to think the same.

And even "pure" nitrogen is never purer than about 95%, which is all
commercial nitrogen generators are capable of making.

However, a lot of gas stations have air
hoses with small compressors that provide the air. I doubt that the
small compressors have air driers on them. Nor do the small pumps that
are plugged into the 12-V power ports in cars.

That's true, but those little compressors don't generally have large
reservoirs that accumulate big puddles of water that could make their way
into tires (or air tools).

Yeah, I know. Instead, the water ends up in the tires, which causes the
tire pressure to vary too much for a given temperature change (although
that's important for NASCAR, not regular drivers). (The compressed air in
those 12-V compressors is also hotter than noncompressed air, which helps
keep water from condensing in the air hose - that why water doesn't drip
out the end - air in the big compressors has more time to cool down to
room or ambient temperature.) If you don't believe me that the air gets
hot, just feel the bottom of foot pump after you use it to fill a bicycle
tire.

The accumulated water with the big air compressor is also a pain in the
winter, when it freezes in the air hose before it gets into the tire.

Compressed nitrogen is also used in hospital operating rooms for use with
the power tools there, like the drills used to put holes for screws into
bones by orthopedic surgeons or holes in skulls by neurosurgeons.

Jeff

#14

I agree. Nitrogen is fine if they are gonna put it in for free. But, it's
not worth the paper it's printed on, so to speak. Nitrogen in the tires is a
"don't care" issue if there ever was one. It's sorta like, paper or plactic?
I don't care, just put the damn groceries in a bag ...

Nitorgen or air? Just fill the tires and get me outa here.

"---MIKE---" <twinmountain (AT) webtv (DOT) net> wrote

I know this has been discussed before but I would like more opinions on
using nitrogen in tires. It would seem that where air is 80 percent
nitrogen it would be foolish to pay extra for "pure" nitrogen in your
tires, Comments please.

---MIKE---

Quote:

In the White Mountains of New Hampshire
(44° 15' N - Elevation 1580')

#15

Mike Hunter wrote:

Quote:

All compressor have driers that remove the water precipitated by the heat of
compression, when proper maintained. LOL

Actually, no. First, heat doesn't cause water to precipitate or
condense. Heat will cause water to evaporate. Second, compression
increases the concentration of water. For example, if the compressor
increases the pressure to 150 psi, then the amount of water in a given
volume is increased by a factor of 10 (from 14.7 psi to about 165 psi -
the 150 psi is 150 psi above regular air pressure). That's because the
compressor literally squeezes everything in the air into a smaller volume.

Jeff

Quote:

"Tegger" <invalid (AT) invalid (DOT) inv> wrote in message
news:Xns9CA8BBE5FC02Ategger (AT) 208 (DOT) 90.168.18...
dr_jeff <utz (AT) msu (DOT) edu> wrote in
news:_pKdnZ3BAMbVEUbXnZ2dnUVZ_vednZ2d (AT) giganews (DOT) com:

Mike Hunter wrote:
As someone said the air inside the tire, as well as the air OUTSIDE
of the tire, is already nearly 80% nitrogen.

Air has something that nitrogen doesn't have: water. Water can
condense or evaporate, causing changes in the pressure of the tire
faster with air than with nitrogen.

But you can get water-free air. That's what the FAA specifies for aircraft
tires when nitrogen is not available.

Any garage with a drier on their compressor can provide water-free air.
Dry
air is what any garage /should/ have, because it prolongs the life of air
tools and helps keeps them from spitting oily goop all over the place.

However, the difference is pretty small; IMHO, not worth the extra
cost. (Note: If you're a NASCAR crew chief, please disregard what I
said. The differences are important for NASCAR cars.)

And for aircraft, whose tires may need to go from -100F to 100F in an
hour.

Nitrogen, for road-going passenger cars, is a nice frill (especially with
those funky green valve caps), but far from essential for safety or
anything else.

--
Tegger

#16

Really? Then why did the water in the air not precipitate, BEFORE it was
compressed above one atmosphere? Are you telling us you believe a
condenser uses heat, rather than water to do what it is designed to do?
LOL

"dr_jeff" <utz (AT) msu (DOT) edu> wrote

Quote:

Mike Hunter wrote:
All compressor have driers that remove the water precipitated by the heat
of compression, when proper maintained. LOL

Actually, no. First, heat doesn't cause water to precipitate or condense.
Heat will cause water to evaporate. Second, compression increases the
concentration of water. For example, if the compressor increases the
pressure to 150 psi, then the amount of water in a given volume is
increased by a factor of 10 (from 14.7 psi to about 165 psi - the 150 psi
is 150 psi above regular air pressure). That's because the compressor
literally squeezes everything in the air into a smaller volume.

Jeff

"Tegger" <invalid (AT) invalid (DOT) inv> wrote in message
news:Xns9CA8BBE5FC02Ategger (AT) 208 (DOT) 90.168.18...
dr_jeff <utz (AT) msu (DOT) edu> wrote in
news:_pKdnZ3BAMbVEUbXnZ2dnUVZ_vednZ2d (AT) giganews (DOT) com:

Mike Hunter wrote:
As someone said the air inside the tire, as well as the air OUTSIDE
of the tire, is already nearly 80% nitrogen.

Air has something that nitrogen doesn't have: water. Water can
condense or evaporate, causing changes in the pressure of the tire
faster with air than with nitrogen.

But you can get water-free air. That's what the FAA specifies for
aircraft
tires when nitrogen is not available.

Any garage with a drier on their compressor can provide water-free air.
Dry
air is what any garage /should/ have, because it prolongs the life of
air
tools and helps keeps them from spitting oily goop all over the place.

However, the difference is pretty small; IMHO, not worth the extra
cost. (Note: If you're a NASCAR crew chief, please disregard what I
said. The differences are important for NASCAR cars.)

And for aircraft, whose tires may need to go from -100F to 100F in an
hour.

Nitrogen, for road-going passenger cars, is a nice frill (especially
with
those funky green valve caps), but far from essential for safety or
anything else.

--
Tegger

#17

Mike Hunter wrote:

Quote:

Did it ever occur to you dr., that although the air inside the tire, as well
as the air OUTSIDE of the tire, is already nearly 80% nitrogen, that there
is far more water OUTSIDE the tire than is ever INSIDE the tire? LOL

Yeah. I know that. And I have said that. But the concentration of the
water changes.

Jeff

Quote:

"dr_jeff" <utz (AT) msu (DOT) edu> wrote in message
news:_pKdnZ3BAMbVEUbXnZ2dnUVZ_vednZ2d (AT) giganews (DOT) com...
Mike Hunter wrote:
As someone said the air inside the tire, as well as the air OUTSIDE of
the tire, is already nearly 80% nitrogen.

Air has something that nitrogen doesn't have: water. Water can condense or
evaporate, causing changes in the pressure of the tire faster with air
than with nitrogen. And, water can also be absorbed and released by the
rubber of the tire. So tires that are filled with nitrogen tend to
maintain a steadier pressure than tires filled with air.

However, the difference is pretty small; IMHO, not worth the extra cost.
(Note: If you're a NASCAR crew chief, please disregard what I said. The
differences are important for NASCAR cars.)

#18

Tegger wrote:

Quote:

And even "pure" nitrogen is never purer than about 95%, which is all
commercial nitrogen generators are capable of making.

Safety tip: If you increase the air pressure of your house to 30 PSI
only by adding nitrogen, your house will become virtually fireproof.

#19

larry moe 'n curly wrote:

Quote:

Tegger wrote:
And even "pure" nitrogen is never purer than about 95%, which is all
commercial nitrogen generators are capable of making.

Safety tip: If you increase the air pressure of your house to 30 PSI
only by adding nitrogen, your house will become virtually fireproof.

No it won't. It's not the percent of oxygen that is important, but,
rather, the concentration of oxygen, in terms of grams per liter. You
can add all the N2 you want, but there will still be the same
concentration of O2.

Jeff

#20

dr_jeff <utz (AT) msu (DOT) edu> wrote in
news:y8ednXAVIIcyZ0HXnZ2dnUVZ_qOdnZ2d (AT) giganews (DOT) com:

Quote:

larry moe 'n curly wrote:

Tegger wrote:
And even "pure" nitrogen is never purer than about 95%, which is all
commercial nitrogen generators are capable of making.

Safety tip: If you increase the air pressure of your house to 30 PSI
only by adding nitrogen, your house will become virtually fireproof.

No it won't. It's not the percent of oxygen that is important, but,
rather, the concentration of oxygen, in terms of grams per liter. You
can add all the N2 you want, but there will still be the same
concentration of O2.

Let's see now....

Atmosphere is 78% nitrogen, 21% oxygen and 1% funny stuff.
78+21+1=100

Let's call it 100 parts per given volume.

Now if you double the pressure using ONLY nitrogen, that becomes 200 parts
in the same volume, so
178+21+1=200

The /concentration/ of oxygen per unit of dimensional space (liter) in the
second case would be exactly the same as in the first, but there'd be a lot
more nitrogen molecules between the oxygens. This would mean that a flame
front would have to kick and punch its way past more than twice as many
inert nitrogen molecules in order to propagate its conflagration. Not
exactly "fireproof", but wouldn't combustion therefore be more difficult to
achieve?

--
Tegger