Best way to fill a bottle

I have heard all sorts of stories of which way is the best way to fill a nitrous bottle. Due to my field of in Medical Gas I know that a certified bottle has to have a complete vaccum drawn on the bottle. Before the bottle can be filled. Now I know the local refill stations aren't going to pull and hold vaccum before they fill. So with that said which method is best to fill your bottle, pumps, mother bottles,cold bottles???

Sometimes you might get a bottle filled and it just doesn't hit right. The first suspect causes are either the guy didn't fill it all the way, or there might be air/trash in the bottle.

Since we never had any way of pulling a true vacuum draw on a questionable bottle to clean it out, we did the next best thing to get it as close as possible. We would take the problem bottle & open it, emptying it almost to the point that no more pressure came out, but closing it just before the point that the bottle might pull any ambient "dirty" air back into the bottle. Then the cool(ish) empty bottle would be placed out in the summer sun to build back up a little pressure. Then after the bottle has cooked in the sun for a while you crack the valve again, and again close it just before it can pull ambient air back into the bottle.

You repeat heating in the sun & venting the bottle a few times until it's clear that your not going to get any more pressure out of the bottle without running the risk of ambient air getting pulled back into it. Then you put the bottle in the freezer, this should create a decent vacuum inside the bottle. Then you get the bottle filled while it's still cold. While this method isn't as good as really having a true vacuum pump drawn on the bottle, it can sometimes be close and help "wake up" a bottle that is causing problems.


As for filling bottles I have done both the gravity/siphon fills & pump fills, both will work OK. Siphon fills are cheaper initially because you didn't spend your money buying a pump, but you never get the last bit of nitrous out of the big storage bottle.The pump fill cost more initially because of the pump cost, but you get as much nitrous as possible out of the big storage bottles. If you have the money to spend, get a pump.

This is the way we use to do it Dave yes it is a pain in the A$$ and you have 3 or 4 deep freezes around but at least you got all of your bottles filled..... we used a 6 or 8 bottle cascade system.... for the syphon bottles.....



Randy

I also have a pump but here is what I did before the pump . I would take the small bottle and put it in my frezzer for a few hours and then transport from the mother bottle to the small bottle (small bottle on the scales). If the big bottle is not hot it may take a couple of fills to get it where you want it. Did that make sense??? Cool story on my pump. Saw it on RacingJunk for about a 100 bucks but was not working. Took a shot and bought it. Send it out to NX and it was fixed for under a 100 bucks! Finally a good deal. I also copied some guys mottle bottle stand on YB to invert the bottle. Works nicely.

I been using the freezer method for years it seems to work ok i do use a 500w bottle heater and pressure gage on the mother bottle the heater is from ARC www.archeat.com and is made for mother bottles it has a chart printed on it for what temp you need for the pressure you need to fill i got it down to a science so i dont under fill or over fill.

Here is how I invert the mother bottle. Copied some guys idea from YB. Works well.
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valleydawg wrote:Here is how I invert the mother bottle. Copied some guys idea from YB. Works well.
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Does the medical grade bottle like that not have a siphon tube ? because the bottles i get all have siphon tubes now and inverting them doesnt help at all.

Man, I wish I knew how you guys are getting those mother bottles... Here in KY you got to have a letter from the pope to get one. Airgas sux ballzzzz.

I went up to the local store to see about getting a couple and they looked at me like I was a methhead, and that was just the Nitrous+ not the medical grade....

8liter wrote:Man, I wish I knew how you guys are getting those mother bottles... Here in KY you got to have a letter from the pope to get one. Airgas sux ballzzzz.

Airgas is where I get mine,..........

You just have to know the right people.

You can get them around here at quite a few gas companys nitrous + thats is , its the medical grade nitrous that you need a license for around here anyway.

Sems to me that if a guy really wanted to draw a vacuum on a nitrous bottle he could use an a/c vacuum pump. After a few hours that bottle would be pretty darn empty.

Greg

Our guy used to love us. We showed up at his shop with our bottles in coolers of ice. We only filled our bottles with 9lbs though. His system had a couple of filters so we weren't really concerned about trash. We use to flush our nitrous system with CO2 between races. Don't know if it helped or not? We would show up and have 8 bottles filled within an hour or so. He had two stations.