Happy Valentine’s Day 2021! Time for me to run out and order some freeze-dried flowers for my wife. What?... yes, it’s true! In case you have not heard of this, freeze-dried flowers can make a beautiful gift.
According to Flowers Forever – Bellabeads of Columbia SC, https://myflowersforeverjewelry.com/pages/freeze-dried-flowers, freeze-dried flowers will, “retain their beauty as if frozen in time as a lasting memento.” They can be placed in shadow boxes or frames and stored for many years.
So this is probably the best time to tell you about this fun application of vacuum technology. I recently worked with one of our vacuum customers who services freeze driers for florists, so this topic is “fresh” in my mind. Freeze drying is well-known for use in the manufacturing of food and drugs. Most likely, you have something in your house that has been processed with freeze-drying. So, let’s take a closer look.
Freeze drying, also known as lyophilization, is a process in which water molecules are removed from biological cells without damaging the cell structure. For starters, the product to be freeze-dried is chilled and the water inside is completely frozen (i.e. placed in the solid state). Next, the pressure is reduced using vacuum pumps and the water molecules sublimate – that is, water goes from the solid phase directly to the gas phase.
The gas load due to the water vapor is usually very high and requires condensers to trap the liberated water and stop it from overwhelming the pumping system. Commercial freeze driers (see image below) include a heat exchanger which serves two purposes: first, the heat exchanger is used to cool the product and later, it is used to gently heat the product to drive the water sublimation.
View inside commercial freeze-drier
Do you know of some other cool applications of vacuum technology, we would “love” to hear from you! Please visit Live chat with us at www.teledyne-hi.com or call 1-800-950-2468.
Special thanks to Flowers Forever – Bellabeads for the use of flower image from their beautiful website.