Nitrogen (again)
in [Toyota]
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From: Mike Hunter on 19 Oct 2009 11:20 All compressor have driers that remove the water precipitated by the heat of compression, when proper maintained. LOL "Tegger" <invalid(a)invalid.inv> wrote in message news:Xns9CA8BBE5FC02Ategger(a)208.90.168.18... > dr_jeff <utz(a)msu.edu> wrote in > news:_pKdnZ3BAMbVEUbXnZ2dnUVZ_vednZ2d(a)giganews.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 >
From: Mike Hunter on 19 Oct 2009 11:25 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(a)invalid.inv> wrote in message news:Xns9CA8C4D7BB1D3tegger(a)208.90.168.18... > dr_jeff <utz(a)msu.edu> wrote in > news:yq-dnafQ09q5B0bXnZ2dnUVZ_hCdnZ2d(a)giganews.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 >
From: Mike Hunter on 19 Oct 2009 11:32 Thanks for the insight, dr. I hope the connection valve differs from the oxygen connection valve. ;) "dr_jeff" <utz(a)msu.edu> wrote in message news:a_2dnYW7PJtfOkbXnZ2dnUVZ_j-dnZ2d(a)giganews.com... > Tegger wrote: >> dr_jeff <utz(a)msu.edu> wrote in >> news:yq-dnafQ09q5B0bXnZ2dnUVZ_hCdnZ2d(a)giganews.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
From: dr_jeff on 19 Oct 2009 15:15 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(a)invalid.inv> wrote in message > news:Xns9CA8BBE5FC02Ategger(a)208.90.168.18... >> dr_jeff <utz(a)msu.edu> wrote in >> news:_pKdnZ3BAMbVEUbXnZ2dnUVZ_vednZ2d(a)giganews.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 >> > >
From: Mike Hunter on 19 Oct 2009 15:33 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(a)msu.edu> wrote in message news:3fKdnf6Cq61DJ0HXnZ2dnUVZ_i2dnZ2d(a)giganews.com... > 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(a)invalid.inv> wrote in message >> news:Xns9CA8BBE5FC02Ategger(a)208.90.168.18... >>> dr_jeff <utz(a)msu.edu> wrote in >>> news:_pKdnZ3BAMbVEUbXnZ2dnUVZ_vednZ2d(a)giganews.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 >>> >>
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