Potpourri starting May 17, 2010

[charlese]

Gotta get in here before the week expires!

Had a close call last week and didn't even know it. No, It didn't involve my body - only my DC 3300.

When cleaning out my DC after vacuuming the floor and the bench top, I removed the stopper at the bottom of the intake manifold. There it was! A nicely cut piece of oak measuring 5/8"X5/8"X2". This chunk had luckily fallen into the stopper and had been secured there by a pack of small dust. If this had hit the fan, I would have been ordering a new one:eek: . Last year a smaller chunk had broken a blade.

Thought I had picked up all of the dangerous pieces from the area before vacuuming:o .

BTW - blew the dust out of the motor. That sure makes the DC sound a lot smoother.

[a1gutterman]

Clarification. You can not say that a nitrogen filled tire is 50% air. It would only be about 50% air if air was compressed and nitrogen was compressed and put in the tire together. To fill a tire they let all of the "compressed air" out and all that is left is residual air that is now under no more pressure than the air outside of the tire. As the "compressed" nitrogen is pushed into the tire that basically zero pressure air inside of the tire is also compressed as much as the final pressure of the tire and then amounts to a very tiny part of the compressed contents of the tire...

Well, I am no engineer, and I may be wrong, but unless the tire is collapsed and has no air in it, I think that the volume of air that is not under pressure is more then the volume of nitrogen that is added under pressure. To me that means that more then 50% of the air in the tire is "regular" air. I am very willing to entertain other views if a qualified person can explain...(sorry farmer, but can you prove the part of your statement highlighted in red above?)

[beeg]

Well 76% of the remaining air in the tire is nitrogen.

[a1gutterman]

Well 76% of the remaining air in the tire is nitrogen.

Absolutely, give or take a few pollutants.

[JPG]

Absolutely, give or take a few pollutants.

Interesting question! Since atmospheric pressure is about 15 psi, does that mean that twice the volume of air(at stp) is in a tire inflated to 30 psi????:rolleyes:

[charlese]

Can't comment now - Too busy playing Pac-Man:p

[iclark]

Can't comment now - Too busy playing Pac-Man:p

google can definitely be surprising.

playing that board with the arrow keys in a T-config is deadly.

[iclark]

Interesting question! Since atmospheric pressure is about 15 psi, does that mean that twice the volume of air(at stp) is in a tire inflated to 30 psi????:rolleyes:

ideally, yes. <sorry for the bad pun>

so, taking 76% N in regular atmosphere from above, that 30psi tire inflated with N would be ~88% N. more if the bead was not sealed from the beginning (frequently the case) because some of regular atm would get purged before the bead sealed.

[a1gutterman]

ideally, yes. <sorry for the bad pun>

so, taking 76% N in regular atmosphere from above, that 30psi tire inflated with N would be ~88% N. more if the bead was not sealed from the beginning (frequently the case) because some of regular atm would get purged before the bead sealed.

I can see the logic for those thoughts, but of course, while the bead is knot sealed, allowing some regular air out as pressurized nitrogen is applied, some of the nitrogen wood also escape, i.e., there is no cheap and easy (let alone accurate) way to measure the amount of Nitrgen in the tire, and there is no discernible way to get 100% Nitrogen in a tire short of mounting it to the wheel while in a room filled with nothing but nitrogen.

[heathicus]

I can see the logic for those thoughts, but of course, while the bead is knot sealed, allowing some regular air out as pressurized nitrogen is applied, some of the nitrogen wood also escape, i.e., there is no cheap and easy (let alone accurate) way to measure the amount of Nitrgen in the tire, and there is no discernible way to get 100% Nitrogen in a tire short of mounting it to the wheel while in a room filled with nothing but nitrogen.

One of the articles I read said they inflated with nitrogen, then purged the tire 3 times to remove the atmospheric air that was in the tire. They also said they tested to make sure they were getting the proper percentage of nitrogen. I assumed that meant they tested the nitrogen content of air being released through the valve stem, but it didn't state that. They could have meant that they tested the air that was going into the tire.