Lyophilization (freeze drying)

[olympic]

I am interested in building my own freeze drier. I have a machine shop and a bunch of scrap thats just beckoning me to build somthing useless. I am all googled out, I havent found much in the way of "do-it-yourself" home made freeze drying instruction. The concept is fairly simple, but building a reliable one is a different story. Freeze the item of interest, drop the pressure, let the H20 sublime and wait until all of the moisture is gone. People use them for food/medicine/taxidermy/book resoration etc. Someone must know of a good website, or have tried to build one.

Thanks

 

[quark]

Some good names in freeze drying are VirTiz, Christ, Usifroid and Steris. LSI gives you cheap lyophilizers but are good. Not to dishearten you but it is not as easy as boxing up things from 'do it yourself' instructions.

First, you have to derive the eutectic point of the product you are going to freeze dry. You should simultaneously check the resistance and temperature of the product while it is being cooled. When the water starts solidifying, you will find a steep increase in resistance and this is the eutectic point of the product. Check the vapor pressure corresponding to the eutectic point. This + losses indicate you the level of vacuum you have to acheive.

Condenser should be maintained atleast 10⁰C below the shell and you should go for an ice layer thickness of not more than 15mm.

Provision should be made for automatic and intermittent pressure rise test to minimize energy wastage. You can also determine the endpoint by eutectic point test but this is too costly.

Nonuniform temperature distribution results in cake collapse and this is a general problem with freeze dryers. Over cooling results in sublimation of product.

Food and Pharma lyophilizers should have the sterilization facility and compliance to 21CFR Part11 is a general requirement now a days.

One lyophilizer we got developed from a local manufacturer is just lying in our junk yard. Building a lyophilizer is easy but building the process is tricky.

Good luck, who knows, you can be one of my prospective suppliers in future and I think I can demand a 50% discount.