HPA Breathing air

HPA Breathing air

Joined: January 16th, 2006, 1:17 am

May 1st, 2011, 3:49 pm #1

Had a question for some of you. I there a difference between diver's air for snorkeling and air from tanks you may find at the hospital? I have these air tanks that are pressurized to 3,000 psi and they are from the hospital. Usually they hook it up for people that have copd or breathing issues. Can I fill my gun with this stuff?

Update:

I just looked on the website...i guess the tanks contain pure oxygen...Sounds ExPlOsiVe! Won't be using that in my guns!!!
Last edited by nitinnelapudi on May 1st, 2011, 3:56 pm, edited 1 time in total.
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Joined: November 9th, 2010, 10:37 pm

May 1st, 2011, 7:48 pm #2

Using pure oxygen could be dangerous but it would be interesting to build a rifle that could cope with it.
I used to play around with putting a dab of petroleum jelly in the back of pellets in a spring rifle. The rapidly compressed air and fuel detonates just like in a deisel engine and makes the rifle more powerful (also makes a nice muzzle flash). You need to use a very light petroleum for it to work (Vicks vapour rub was the best I could find) but with pure oxygen a heavier oil with much more energy could be used.
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Joined: April 1st, 2009, 3:18 am

May 1st, 2011, 9:49 pm #3

...You will most likely cause an explosion filling such a gun with liquid oxygen once it comes into contact with the grease and oils inside the gun alone; the orings will have lube on them from assembly.

Not a very bright idea at all.

Such an attempt would land you the Darwin award.

"Well, I thought it was a rabbit but it turned out to be Bear Grylls in a rabbit hide."

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Joined: November 17th, 2006, 3:51 am

May 2nd, 2011, 1:41 am #4

Had a question for some of you. I there a difference between diver's air for snorkeling and air from tanks you may find at the hospital? I have these air tanks that are pressurized to 3,000 psi and they are from the hospital. Usually they hook it up for people that have copd or breathing issues. Can I fill my gun with this stuff?

Update:

I just looked on the website...i guess the tanks contain pure oxygen...Sounds ExPlOsiVe! Won't be using that in my guns!!!
..as well as compressed Oxygen, but the tanks should be of different colors and clearly labeled as either "oxygen" or "air". Will also find Nitrogen, co2, and perhaps Argon tanks at many hospitals.

Normally the small tanks (the size folks can easily carry) are 2000psi tanks (the tanks will have 2015PSI stamped on them someplace)...these are the ones that people are likely to drop, knock over, or run into the wall with. I;ve used the small sized ones (repainted gray, marked co2, and with a co2 type fill valve) for co2 bulk filling....they safely hold about 6 pounds of co2.

Its the heat of compression... when you fill a gun from a tank, the air tube on the gun gets warm. Fill it fast, and it gets hot. Use oxygen, and it often can go "boom".
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Joined: November 9th, 2010, 10:37 pm

May 3rd, 2011, 9:55 pm #5

...You will most likely cause an explosion filling such a gun with liquid oxygen once it comes into contact with the grease and oils inside the gun alone; the orings will have lube on them from assembly.

Not a very bright idea at all.

Such an attempt would land you the Darwin award.

"Well, I thought it was a rabbit but it turned out to be Bear Grylls in a rabbit hide."

..but I wasnt suggesting using it in a crosman. I was thinking some kind of specially made combustion chamber behind the breech into which the pressurised oxygen (Or maybe NOx) could be injected trough a non return valve. As an engineer caseless fuel/ammo and an oxidising gas seems like an interesting concept for a rifle to me...but I guess there must be a reason why noone makes them already.

The petroleum jelly in a spring/HPA rifle does work well though, you should try it.
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Joined: January 21st, 2011, 6:05 am

May 4th, 2011, 2:47 am #6

google "combustion rifle" and such. The problem is getting fluid oxidants, oxidizers and a combustion initiator together quickly enough in a controlled manner. There would be certain advantages to such a system, such as being able to change the projectile and the charge independently in the field, transportation of materials would be more complicated but safer, etc.

Higher powered springers do this anyway, called "dieseling" of the seal and breech lubricants. If it happens on the seal side, it will eat your seal in a hurry because the seal isn't meant for that kind of heat build up.

I know someone once did some chronometer tests in dieseling and non-dieseling condition. I believe the results were inconclusive as to whether or not there is an increase in muzzle energy during dieseling.

I don't know if the "combustion rifle" experimenters have thought about starting with a springer to supply the compressed oxidant, using the sudden compression as the initiator and applying the oxidant in the breech. If you put a secondary seal between the spring chamber and the breech, you might be able to protect the seal. The nice thing about that is that the respective chambers could be charged independently and the timing would be set by the release of the sear on the spring. I doubt it would be any different than doping the pellet with Vicks, although you might be able to make it more reproducible.



"Bones heal, chicks dig scars, pain is temporary, glory is forever."
-Evel Knievel
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