A lyophilizer is a laboratory instrument used for lyophilization, that is to say, it is used to remove moisture from a product by drying it cold, thus generating a dehydrated product that can be rehydrated when needed without losing its properties at the time of use.

Freeze-drying is a drying or dehydrating process that is performed by progressive sublimation of the solvent or water present in a sample. This process is characterized by using low temperatures which prevents some volatile elements from being lost, unlike in conventional drying processes. Progressive sublimation allows the direct passage of ice (solid) to gas (vapor) without passing through its liquid phase.

Basic structure of a lyophilizer

• Dry chamber: is the place where the substance or product to be lyophilized is placed. It can be presented in different forms with compartments where sublimation occurs, passing water from solid to vapor. Its closure is airtight and works with vacuum.
• Condenser with cooling circuit: This equipment communicates with the dry chamber and is where the steam generated in the sublimation condenses. A coolant keeps it at a lower temperature than the dry chamber (-50 to -125 ºC).
• Vacuum system: The vacuum is generated with an oil pump that works on 10-2 mbar connected to a trap so that no vapors from the solvent pass into it. The vacuum system first removes air from the dry chamber when initiating the freeze-drying process, and then helps sublimation.

Criteria to be taken into account for the selection of a lyophilizer

Before buying a freeze-drier, it is important to take into account the objectives of research and production. Features such as sample size and sample type are key factors to consider. While desktop models are ideal for small volumes, floor standing models are ideal for large scale applications. It is also important to note that:

• When it comes to sampling types, a difference of 15-20°C is needed between the eutectic temperature of the sample and the collecting chamber.
• While most biological samples can be frozen using a standard system that reaches -50°C, some samples, such as high performance liquid chromatography/HPLC preparations in acetonitrile/CH3CN, will need a cascade-type collector that reaches -84°C to accommodate the lower freezing points.
• In addition, an ultra low temperature (up to -105°C) lyophilizer may be required to accommodate methanol preparations (eutectic point -97.6°C).
• For acid samples that can deteriorate the stainless steel coils of the equipment, a polytetrafluoroethylene/PTFE coating is advised, as well as a hybrid type pump. Also, fluid volume should be considered.
• While lyophilizers with a small capacity can accommodate tissue samples with small amounts of liquid, food products can contain higher amounts of liquids and require units with a larger capacity. It should be noted that the capacities of the collector can vary from 2.5 to 18 liters, with different shelves and supports.

When is a lyophilizer needed?

A lyophilizer is an essential instrument in the pharmaceutical and food industry, it is a very useful equipment when you want to conserve products, because it allows to remove moisture through cold drying.

The material to be lyophilized is introduced into the equipment, where there are very low temperatures, usually below – 40°C. With a vacuum pump, the pressure in the equipment is reduced. Having lowered the temperature the organic water or solvent freezes. Subsequently, when the pressure is lowered, the water that is in solid state is steamed into the process known as sublimation.

What does Kalstein offer you?

Kalstein is a manufacturer of medical and laboratory equipment of the highest quality and the best technology at the best PRICES in the market, so you can make your PURCHASE confidently with us, knowing that you have the service and advice of a company specialized in the field and committed to provide you with safe, economical and effective options to perform your functions in the right way.

This time we present our vertical laboratory lyophilizer YR05190. This innovative equipment with cutting edge technology has the following features:

• CFC-free cooling.
• LCD screen drying curves, English interface.
• Large condenser opening, condenser with pre-freeze function.
• Low noise compressor, good efficiency, long service life.
• The condenser and the operating panel are all stainless steel.
• The drying chamber with organic glass is safe and visible.
• The shelf and tray are stainless steel, the space between trays can be customized.
• Small volume, easy and convenient operation.
• The nitrogen valve is optional.
• The eutectic point testing device is optional.
• The communication interface is optional.
• Cascading cooling is optional, applied for -80℃ devices.

For more information we invite you to take a look HERE