Question Determining SAC Rate

[34109411]

To convert cf/min to psi/min, multiply by psi/cf for the cylinder you are using. For an AL80, that is 3000/77.4 = 38.8, so call it 40. Your 0.35 cf/min would be 14 psi/min.

However, I find nothing in the Mares Quad manual about it displaying SAC in cf/min (or in ANY units), and if it is able to do this then it would already know your tank information, which you must have given it. I find nothing in the manual about that, either.
Also, it is unlikely to display "CF/m" since "m" is the abbreviation for meters, not minutes.
So, I have no idea what you are talking about.!

let me try to get a pic next time maybe didn't read correctly.

 

[34109411]

ok sorry so it s by pressing the right down button it does show 0.35 CF/MIN . I did 3 dive today and look carefully at the screen.

 

[happy-diver]

I punch my dive into MultiDeco using the highest rmv then grab the biggest tanks then fill them the most

and always come back

 

[34109411]

please i need a brain here...

80 cf tank/1.07=74 min of gas at 32 feet

80 cf tank/1.60=51 min of gas at 60 feet

80 cf tank/ 2.24= 35 min of gas at 100 feet

-------------------------------

30 cf tank/1.07= 28 mi of gas at 32 feet

30 cf tank/1.60= 19 min of gas at 60 feet

30 cf tank/2.28= 13 min of gas at 100 feet

so question is for 80 cf tank i know for exemple that if i use let say 70 CF of air this will be 2692 psi (70/0.026)

i am not able to apply the same for a 30 CF tank why ??? i dont understand i must misunderstood something because obviously the working pressure of 30 cf tank is still 3000 psi ?? i am not able to get the right psi consumed out of a 30 CF tank. i guest i over complicated... (for people asking the 30 cf is a bailout)

thank you for all the help

 

[inquis]

i am not able to get the right psi consumed out of a 30 CF tank

You're just multiplying by 1, but written as the ratio of equivalent things. 20 cf out of a 30 cf tank is 20 cf * (3000 psi / 30 cf) = 2000 psi because the cf units cancel. (The equivalent things are 3000 and 30 cf). The conversion factor is 100 psi/cf or the inverse, 0.01 cf/psi. Multiply or divide as needed to get the units to cancel.

 

[gbirch]

please i need a brain here...

80 cf tank/1.07=74 min of gas at 32 feet

80 cf tank/1.60=51 min of gas at 60 feet

80 cf tank/ 2.24= 35 min of gas at 100 feet

-------------------------------

30 cf tank/1.07= 28 mi of gas at 32 feet

30 cf tank/1.60= 19 min of gas at 60 feet

30 cf tank/2.28= 13 min of gas at 100 feet

so question is for 80 cf tank i know for exemple that if i use let say 70 CF of air this will be 2692 psi (70/0.026)

i am not able to apply the same for a 30 CF tank why ??? i dont understand i must misunderstood something because obviously the working pressure of 30 cf tank is still 3000 psi ?? i am not able to get the right psi consumed out of a 30 CF tank. i guest i over complicated... (for people asking the 30 cf is a bailout)

thank you for all the help

Not sure what you are asking here, if your question is "If I breathe 12cuft (for example) out of a 30cuft/3000psi cylinder, what is the drop in pressure?", then the answer would be:
3000/30*12 = 1,200psi

The information above (your breathing rates at various depths) seems irrelevant to the question - hence my confusion.

 

[34109411]

You're just multiplying by 1, but written as the ratio of equivalent things. 20 cf out of a 30 cf tank is 20 cf * (3000 psi / 30 cf) = 2000 psi because the cf units cancel. (The equivalent things are 3000 and 30 cf). The conversion factor is 100 psi/cf or the inverse, 0.01 cf/psi. Multiply or divide as needed to get the units to cancel.

thank you i will work it out i think i got it !

 

[34109411]

Not sure what you are asking here, if your question is "If I breathe 12cuft (for example) out of a 30cuft/3000psi cylinder, what is the drop in pressure?", then the answer would be:
3000/30*12 = 1,200psi

The information above (your breathing rates at various depths) seems irrelevant to the question - hence my confusion.

thank you for you help ok now !