lermontov
Contributor
ok so ive got a mystery I cant solve maybe others can help work it out
on a recent trip I mixed a 17/38 starting with 1 BAR and 21% (empty cylinder)
the calculator stated :
81 BAR He
Fill to 92.1 BAR 02
Fill to 200 Bar air
but when analysed I get 17/20 -thinking I must either have a contaminated He source or somehow dropped some gas , cross checked the He supply and i have over 99%, cross checked the pressure i have 200Bar
second option was the analyser was wrong so cross checked that with another gas source -air ( ok) helium ( ok ) 02 ( ok) cross checked with another analyser and also read 17/20
so if I do the math
81Bar He /200 bar fill = 40.5%
11.1 02 / 200 = 5.6%
air of 108 Bar =108X.79 n2 = 85.3 Bar of N2 / 200 = 42.6%
and 108 Bar x.21 02 = 22.7 Bar of 02 /200 = 11.3% o2
total Gasses are
40.5% He
42.6% N2
16.9 % o2
totals 100%
but analyser says 17/20
the o2 content is spot on so that implies the N2 is also spot on
so wheres my helium gone?
on a recent trip I mixed a 17/38 starting with 1 BAR and 21% (empty cylinder)
the calculator stated :
81 BAR He
Fill to 92.1 BAR 02
Fill to 200 Bar air
but when analysed I get 17/20 -thinking I must either have a contaminated He source or somehow dropped some gas , cross checked the He supply and i have over 99%, cross checked the pressure i have 200Bar
second option was the analyser was wrong so cross checked that with another gas source -air ( ok) helium ( ok ) 02 ( ok) cross checked with another analyser and also read 17/20
so if I do the math
81Bar He /200 bar fill = 40.5%
11.1 02 / 200 = 5.6%
air of 108 Bar =108X.79 n2 = 85.3 Bar of N2 / 200 = 42.6%
and 108 Bar x.21 02 = 22.7 Bar of 02 /200 = 11.3% o2
total Gasses are
40.5% He
42.6% N2
16.9 % o2
totals 100%
but analyser says 17/20
the o2 content is spot on so that implies the N2 is also spot on
so wheres my helium gone?