Description

Welcome to our company’s advanced lyophilizer, offering innovative solutions for a wide range of applications. Our state-of-the-art equipment is specifically designed to cater to the diverse needs of laboratories, homes, industrial facilities, and pilot-scale operations. In this detailed page, we will explore the different specifications and capabilities of our versatile freeze dryers, highlighting their benefits and applications. Contact us today to discover efficient freeze drying solutions tailored to your requirements.

Lyophilizer Types

Stages of freeze drying

There are four stages in the complete freeze drying process: pretreatment, freezing, primary drying, and secondary drying.

Pretreatment

Pretreatment includes any method of treating the product prior to freezing. This may include concentrating the product, formulation revision (i.e., addition of components to increase stability, preserve appearance, and/or improve processing), decreasing a high-vapor-pressure solvent, or increasing the surface area.

Freezing and annealing

During the freezing stage, the material is cooled below its triple point, the temperature at which the solid, liquid, and gas phases of the material can coexist. This ensures that sublimation rather than melting will occur in the following steps.

Structurally sensitive goods

In the case of goods where preservation of structure is required, like food or objects with formerly-living cells, large ice crystals will break the cell walls which can result in increasingly poor texture and loss of nutritive content. In this case, the freezing is done rapidly, in order to lower the material to below its eutectic point quickly, thus avoiding the formation of large ice crystals. Usually, the freezing temperatures are between −50 °C (−58 °F) and −80 °C (−112 °F).

Primary drying

During the primary drying phase, the pressure is lowered (to the range of a few millibars), and enough heat is supplied to the material for the ice to sublimate. The amount of heat necessary can be calculated using the sublimating molecules’ latent heat of sublimation. In this initial drying phase, about 95% of the water in the material is sublimated.

Secondary drying

The secondary drying phase aims to remove unfrozen water molecules, since the ice was removed in the primary drying phase. This part of the freeze-drying process is governed by the material’s adsorption isotherms. In this phase, the temperature is raised higher than in the primary drying phase, and can even be above 0 °C (32 °F), to break any physico-chemical interactions that have formed between the water molecules and the frozen material.

After the freeze-drying process is complete, the vacuum is usually broken with an inert gas, such as nitrogen, before the material is sealed. At the end of the operation, the final residual water content in the product is extremely low, around 1% to 4%.

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