Scale up of Centrifuge

[Jigneshpadia2002]

Hi Everyone,

I am a biotechnologist! I am working in a process development area. I am very much keen to learn about the engineering principles and rule of thumbs of scale-up. Recently during my literature survery I came across a strange Dimensionless number for centrifuge scale-up.

During my postgraduation I did learn about Sigma factor for scaling up centrifuges but in this literature they have mentioned Leung number, which is some sort of dimensionless number very similar to Re (Reynolds) number.


The very brief text was like this

"Le is directly related to cut size - maximum size in the supernatant, minimum size in sediment and it also depends on centrifuge design geometry and property of the fluid involved for separation."


Does anyone has any idea about this? Can anyone help me to understand more about it or any other aspect of centrifuge scale-up.


I strongly prefer in Filtration proocess becuase they are easier to scale-up but I do like the challenge to understand the concept of scale-up in centrifuges.


Thanks a lot in advance for your valuable contibution.

 

[StoneCold]

Jigneshpadia2002
I will tell you the little I know about centerfuging but it does not have anything to do with dimentionless numbers.
You can determine if a product can be separated by centerfuging by putting a sample in a jar. If it separates on it's own in less than 2hr(I think?) then centerfuging will work to make the separation.
You can scale up the centerfuge process by keeping the centripital force on the product the same for the two centerfuge sizes. If I was a good engineer I would give you the relationship between rpm and bowl radius that you could use to scale up the process but I don't have a reference handy.

Hope this helps some.
StoneCold

 

[shahyar]

For Scaling up, in centrifuges you have to use "Q/Sigma" .
Q is flowrate to centrifuge.
Roughly, sigma is:
Sigma= (1/178)*(rpm)^2* LCyl. * Ro^2
some refrences mentioned 160 instead of 178.
Hope this help.