How to freeze dry liquids

What a freeze dryer is

Freeze dryer is a technique of drying by using the principle of sublimation. It is to freeze the dried material at low temperature and then sublimate the frozen water molecules in a proper vacuum oven environment. It is a process that makes frozen water molecules into water vapor evolution. A home freeze dryer can freeze the water-containing substance into a solid state first, and then sublimate the water therein from the solid state to a gaseous state to remove the water and preserve the substance. A home freeze dryer consists of a refrigeration system, a vacuum system, a heating system, and an electrical instrumentation control system. It can be used in food-making field, pharmaceutical field, industrial field, biological field and other fields.

The vacuum system of the freeze dryer consists of a freeze dryer, a water vapor condenser, a vacuum valve, and a vacuum pump. The degree of vacuum during lyophilization is approximately 67 to 0.13 Pa (5 x 10-1 to 1 x 10-3Torr). The pre-vacuum of the freeze-drying system requires that the required vacuum should be achieved in about 30 minutes.

freeze dryer
freeze dryer

Then people maybe wonder how to freeze dry liquids, next let’s go through the process together : Before freeze drying materials, we need to compound the materials into liquids with certain concentration. And materials that need to be freeze dried should be compounded into liquids with 4%-25% solid substances concentration(10%-15% is the best), so that the materials could have a good shape finally. The freeze-drying process generally consists of three steps: pre-freezing, sublimation drying (or the first stage drying), analytical drying (or the second stage drying).

Firstly, pre-freezing is to solidify the free water in the solution and give the product the same shape after drying as before, and to prevent irreversible changes such as foaming. Secondly, when frozen products are heated in sealed vacuum containers, their ice crystals will sublimate to vapor and escape, resulting in dehydration and drying of the products. Thirdly, in order to improve the storage stability and prolong the shelf life of the product, it is necessary to remove moisture that is adsorbed on the capillary wall and polar groups of dry matter.

How does a home freeze dryer work

  There are three stages in a home freeze dryer’s working process:

  1. The first stage of a home freeze dryer’s working process is freezing stage. In this stage, the freeze dryer cools the material below its triple point.

  2. The second stage of a home freeze dryer’s working process is sublimation stage. In this stage, the solid water (ice) in the materials gets sublimated directly into water vapor under vacuum environment. In this way, water gets removed and the materials get dried. The vacuum system establishes low-pressure conditions for the sublimation drying bin.

  3. The second stage of a home freeze dryer’s working process is second sublimation stage. In this stage, the temperature will get higher than the second stage in order to dry materials. The structure of materials are porous.

  During the whole working process, there is always a vacuum system. And when the process ended, the vacuum system will break down by itself.

freeze dryer
freeze dryer

Does freeze drying remove water

As we talked above, freeze drying is to freeze materials into solid-phase firstly and then sublimate water within these solid materials directly into vapor. So in this process, water within materials get into ice and then gas. And finally water within materials get out of the materials as vapor. Therefore, freeze drying removes water in this way.

How long does freeze drying take

Many people wonder “how long does freeze drying take”? The answer is “it depends”. Now let me tell you the reason. The time that freeze drying takes varies because of the different applications and conditions of freeze drying. Generally, it takes one day or two days for freeze drying to work. Freeze drying mostly takes one day or two days and there are still some exceptional examples.

What is the difference between freeze drying and Lyophilization

Freeze drying and Lyophilization are very similar but there are still some differences here between the two. They both are methods that is to freeze materials into solid-phase and then sublimate water within them into gas-phase directly under vacuum. Freeze drying and Lyophilization can be different from each other when they are in different industrial situations and venues.

freeze dryer
freeze dryer

The types of drying machine

Drying machine is widely used in many fields, for example, industrial field, chemical field, drying food machine for home use, drinking field, petroleum and chemical industry field, oil and fat industry field, synthetic fiber industry field, textile printing and dyeing work field, non-woven industry field and so on.

There are so many kinds of drying machine for using in different field, for example, food drying machine for people’s daily life, industrial drying machine for industrial usage, industrial air dryer, industrial hemp drying equipment, industrial freeze drying equipment, industrial food drying equipment, industrial paint drying equipment and so on.

Freeze drying food machine for home use

Freeze drying food machine is quite popular at people’s daily life at home. Freeze drying food machine for home use is a small vacuum freeze dryer. It can be applied to the use at home and other use. It is widely used in the freeze drying of fruits, all kinds of meats, vegetables, herbs, health care and so on.

Freeze frying food machine is operated by people through touch screen buttons, and it can be automatic during the working process, which is very convenient and relaxing for people. It has an advanced system, small running current and it is energy-saving.

It has a food-level stainless steel 304 plate and inner design, which is very safe and guaranteed. Besides these practical characteristics, this machine still has a beautiful appearance and compact size.

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