Helium SCUBA

         Helium SCUBA Storage Tank 160 Cubic Feet        

For a storage tank of 160 Cubic feet @ 1800 PSI, and a desired 33% of Helium: fill the 8 SCUBA Diving Tanks (80 Cu. Ft. @3000PSI) to the pressure in the first Orange background. Ex: the first 2 shown are 999 and the third ops tank is filled to 923.4 PSI, etc. The numbers that follow after the storage tank has dropped below the pressure required to get the percent desired, for the first storage tank are not important as you just equalize the empty SCUBA tank with the storage tank (only after the storage tank has dropped below the fill pressure for the desired % Helium). Filling the first tanks slowly will minimize heating which can cause a false  (High) reading.

Then use the second storage tank to top off the tanks not at 33%.

When finished with the Helium fill the tanks to 3000 PSI with standard air. Always check the finished tanks with Oxygen and Helium Analyzers to verify fill and use Mixed gas computers properly adjusted for the mix indicated for SCUBA diving.

                        

Storage tank   Ops Tanks #1   Fill ops to:   Storage drops to:   Storage tank #2            
PSI Cu. Ft.   psi Cu. Ft.   % PSI   Cu.Ft. PSI   PSI Cu. Ft.            
                                     
1800 160   3000 80   33.3 999   133.4 1500   1800 160            
*****************************************************************************************************          
    Ops Tanks #2   Fill ops to:                        
    psi Cu. Ft.   % PSI                        
                                     
    3000 80   33.3 999   106.7 1201                  
*****************************************************************************************************          
    Ops Tanks #3   Fill ops to:         Ops Tanks #3   Fill ops to:   Storage #2 drops to:
    psi Cu. Ft.   % PSI         psi Cu. Ft.   % PSI   Cu.Ft. PSI
                                     
    3000 80   30.78 923.4   82.1 924   3000 80   33.3 999   158.0 1777
***************************************************************************************************** **************************************
    Ops Tanks #4   Fill ops to:         Ops Tanks #4   Fill ops to:      
    psi Cu. Ft.   % PSI         psi Cu. Ft.   % PSI      
                                     
    3000 80   23.68 710.4   63.2 710   3000 80   33.3 999   150.3 1691
***************************************************************************************************** **************************************
    Ops Tanks #5   Fill ops to:         Ops Tanks #5   Fill ops to:      
    psi Cu. Ft.   % PSI         psi Cu. Ft.   % PSI      
                                     
    3000 80   18.2 546   48.6 547   3000 80   33.3 999   138.2 1555
***************************************************************************************************** **************************************
    Ops Tanks #6   Fill ops to:         Ops Tanks #6   Fill ops to: