Oxygen pickup in silicone beer line

[smort]

Hi I want to have 15 inch of silicone tube (ID 1/8" , OD 1/4") in a beer transfer line. The Permeability Coefficient for the silicone tube is given at a value of 8025 (Oxygen). Flow rate is continuous (1 quart/minute) and the liquid passes only once. Pressure inside the tube is 10-15psi. Does anyone have an opinion if the oxygen pickup through this short piece of tube will affect my oxygen ppb in the beer?

 

[balrog]

Paging @doug293cz ...

(he knows many much thingsen)

 

[doug293cz]

Got a link for the formulas you cut 'n pasted? The pressure drop is not the pressure exerted by the fluid on the tubing, but rather the partial pressure of O2 outside the tubing minus the pressure of O2 that would be in equilibrium with the concentration of dissolved O2 in the beer at the current beer temp.

Brew on

 

[smort]

Thanks @doug293cz. They are from the tubing datasheet. So if partial pressure is to be used then it would be 20.9%*atm=22.04cmHg on the outside and on the inside 0.0%*atm=0cmHg? I don’t know the dissolved oxygen concentration in the beer other than it’s low, hopefully below 25ppb. The numbers I am getting says the beer ends up quite a lot ppb of oxygen higher but I am not confident in my own math.

 

[doug293cz]

Thanks @doug293cz. They are from the tubing datasheet. So if partial pressure is to be used then it would be 20.9%*atm=22.04cmHg on the outside and on the inside 0.0%*atm=0cmHg? I don’t know the dissolved oxygen concentration in the beer other than it’s low, hopefully below 25ppb. The numbers I am getting says the beer ends up quite a lot ppb of oxygen higher but I am not confident in my own math.

Do you have a link to the tubing datasheet? Getting the units correct is critical to the calculations, which is why I want as much info on the formulas as I can get.

Brew on

 

[smort]

Thanks @doug293cz I just sent you the datasheet. Oxygen Permeability Coefficient is given as 8025 x10^-11 cc*cm/cm2*s*cmHg (!)

 

[TLaffey]

Thanks @doug293cz I just sent you the datasheet. Oxygen Permeability Coefficient is given as 8025 x10^-11 cc*cm/cm2*s*cmHg (!)

I'm interested in this calculation result. But why not use Santoprene instead of silicon tube?

 

[smort]

There are many good alternatives, Tygon XL-60 for example, but it's $$$

 

[marc1]

There are many good alternatives, Tygon XL-60 for example, but it's $$$

Evabarrier tubing has pretty good O2 resistance and is fairly inexpensive.