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Best gas for PCPs

Posted: Sat Jan 30, 2010 12:52 pm
by karizman
Nitrogen should be a better choice than plain air for PCPs. I will put forth advantages & disadvantages of few gases to be able to decide yourself the best gas for your PCP.

It is a well known fact that most of chemical reactions & oxidation is caused in the presence of water or humidity & gases which promote combustion. Above mentioned destructive reactions are greatly accelerated under pressure & PCPs are always pressurized.

Pure air is safe but it still contains traces of water which can corrode your valves & cylinders in long term. Hill pumps with Dry-Pack are able to remove almost 98% humidity from plain air & they are considered the best in the world to provide you with driest possible air but they also can't remove all the moisture from air. Pure air also contains oxygen in sizable quantity to promote combustion if carelessly handled ( Very fast filling of cylinder, leaving out in sun or closed cars, using oil of any kind through air passageway etc.) All this can happen in very rare condition but still there is a possibility of accident even if you use plain air. The advantage of using air is that it can be compressed to very high pressure & is also available easily.

Co2 is inert gas which does not promote combustion but very sensitive to temperature changes & can't be pressurized higher. It also contains water traces which is very dangerous to your valves & cylinder of any metal because Co2 + Water + some impurities + High Pressure = Carbolic acid. Co2 is also very very permeable gas. It means it can sip through best sealing materials & damage the same through process. That is why it is advised to store Co2 guns / pistols empty if not used for more than 5-6 days. It is a sure way to damage your seals. Low pressure & temperature sensitivity does not allow consistent performances & higher velocities.

Nitrogen on other hand is most inert gas which is non-reacting under normal pressure (below 300 BAR & 500 degree centigrade ) & temperature. It does not contain water traces. It is used to displace water in food packaging. It also displaces oxygen in close quarters. It is completely non-combustive. It so safe that fuel tanks of space shuttle are covered under pressurized nitrogen outer casing to avoid any premature combustion or explosion. It is also used as top safety layer on all liquid explosives to avoid their contact with oxygen or any other combustible material. Due to it's temperature stability, dry state & non-oxidative qualities it is used in aircraft tiers. It can be pressurized very high, in some cases upto 6000 psi also.

So for me Nitrogen is the first choice any day. I can get more fills from same sized cylinders. Consistent performance. Higher velocities due to higher pressure & the best part is non - combustion & non- reactivity makes it the safest gas for instruments & people alike.

Re: Best gas for PCPs

Posted: Sat Jan 30, 2010 9:17 pm
by farhan.lateefi
Hi,

Great info man,actually i was wondering if i could use nitrogen for my PCP and here you are with this info!! now i will have to source the gas from somewhere..any sugesstions?? anyone...

cheers
farhan