Epsilon 2-6D LSCplus

Pilot freeze-dryer

Compact floor-standing unit for process optimisation and process development

Epsilon 2-6D LSCplus

The Epsilon 2-6D LSCplus freeze dryer is a general-purpose, high-performance laboratory and pilot unit for drying solid or liquid products in vials, ampoules, tubes, other glass containers or dishes.

The applications of the Epsilon 2-6D LSCplus freeze dryer include the drying of bacteria or cultures, viruses, blood plasma, serum fractions, antibodies, vaccines, medicines such as chloramphenicol or streptomycin, vitamins, biomass and plant extracts for biochemical tests.

The Epsilon 2-6D LSCplus is also ideal for product development and small-scale production activities.

Technical data

Ice condenser capacity:6 kg
Ice condenser temperature:–88 °C
Shelf dimensions:225 x 300 mm (W x D)
Number of shelves:1 to 6
Shelf area:0,0675 m2 to 0,3375 m2
Shelf spacing:249 mm to 31 mm
Shelf temperature:–50 °C  to +60 °C


Shelf temperature accuracy:max. ±1 °C
Cooling systems:2 independent systems, air cooled (optionally water cooled)
Ice condenser cooling system:2 compressors, 0.6 kW each, in cascade configuration
Shelf cooling system:1 compressor, 0,6 kW
Unit dimensions:1267 x 860 x 650 mm (H x W x D)



Process optimisation

WTMplus 2.0 – Wireless Temperature Measurement

The WTMplus 2.0 (wireless product temperature measurement system) avoids the disadvantages arising from the use of wired temperature sensors. It is significantly easier to use in practice. There is no need for temperature sensor cables or connectors inside the vacuum chamber. The wireless self-powered sensors are placed manually or automatically when the product vials or dishes are filled and report the corresponding product temperatures to the unit controller during the entire lyophilisation process.

Technical data

Probe dimensionsLength: 21 mm plus 29 mm flexible antenna
Diameter: 2.8 mm
Temperature measuring range–60 °C to +135 °C
Measurement accuracy±1,0 K
Temperature resolution0.1 K

Comparative pressure measurement

In addition to product temperature measurement and pressure rise testing, the simultaneous use of two vacuum sensors with different measuring principles can provide information about the progress of the drying process. The commonly used Pirani gauge indicates higher absolute pressures at the start of the primary drying phase because its operation is dependent on the gas type and large amounts of water vapour are released at the start of the primary drying phase. By contrast, capacitive pressure sensors are independent of the gas type. The approaching end of the primary drying phase, which occurs when there is no longer a significant concentration of water vapour, is indicated by the gradual approach of the two pressure curves to each other during the process.

Sample extraction system

The sample extraction system allows individual sample containers to be removed under vacuum during the drying process without interrupting the drying process. This is done by using a gripper arm to pick up the sample container, close it, and remove it through a vacuum lock. This allows individual sample containers or vials to be removed from the freeze dryer at defined intervals. The samples removed through the vacuum lock can be investigated and analysed in parallel with the ongoing process. This allows the progress of the process to be measured and documented in detail.

Technical data

Sample containers/vials:6R to 30R
Max. 50H
Coupling flange:DN 160 clamp
Gripper working range:200 mm
Stoppering device:Teflon-coated plunger
Vacuum lock:DN50
Materials:Stainless stell 1.4404 and 1.4435, Teflon, Borosilicate glass
Visualisation:Direct or with a digital camera, lighting fixture and monitor


Cleanroom installation

To conform to even the most stringent requirements for the cleanliness of the production environment and ensure compliance with applicable regulations, the freeze drier can be integrated into a cleanroom.

Glove box connection

High safety requirements are often imposed on unit operation in practice. For example, combinations of freeze dryers and glove boxes are used when freeze drying is necessary to protect products against harmful environmental factors or because the products concerned are highly active and possibly toxic. A special docking frame is used to connect the freeze dryer directly to the glove box. This isolates the entire drying chamber and the working area for product preparation from the technical surroundings.

Implementation using standard docking frames. Special versions are possible on request.

Manual and hydraulic stoppering devices

A manual or automatic stoppering device, depending on the unit type, is used to close drying containers or vials by pressing in stoppers. Electrohydraulic stoppering devices with stainless steel bellow seals are used in particular in pharmaceutical applications.

H2O2 disinfection

Sterilisation with vaporised hydrogen peroxide (VHP; H2O2) is an economical and effective alternative to pure manual disinfection using isopropanol or similar substances and steam sterilisation, which is common practice in production processes.

VHP is especially worthwhile in situations where the capital cost of installing steam sterilisation equipment is too high, but the benefits of using a reproducible process are necessary. With the VHP method, the freeze dryer is connected to a suitable VHP generator in a closed loop, usually by means of hoses and quick-release couplings, so that the VHP generator can also be as needed with other equipment.

Cleaning flange

The generously sized cleaning flange simplifies the inspection and routine cleaning of the ice condenser chamber.

Special solutions

Solvent-resistant version

Along with freeze-drying of aqueous media, freeze drying of substances containing aggressive solvents is necessary in some areas such as pharmaceutical research. All of the solvents in this connection have freezing points within the technically manageable range, such as DMSO (eutectic point +15 °C), tertiary butanol (+25.5 °C), dioxane (+12 °C) or acetonitrile (–45 °C). Freeze dryers for this application scenario are designed to be chemical resistant, which means they have modified valves and door seals, special vacuum pumps, and modified cooling systems. The particular advantages of lyophilisation compared to liquid removal by evaporation are the better structure of freeze-dried products (powdery or sponge-like, rather than a viscous mass), lower final solvent content and gentler handling.


Drying and ice condenser chambers are inertised by flushing them with an inert gas, such as nitrogen or argon. The air in the chambers at the start of the process, including the oxygen present in the air, is displaced by the inflowing inert gas. This method is used in particular for the drying of products containing solvents for which an inert atmosphere is required in the process chamber.

Shelf spacing adjustment

The distance between the shelves can be changed to adapt the shelves to containers of different heights, such as vials or product dishes. This allows the available shelf capacity to be used optimally.

Drying manifold

The scope of use of pilot freeze dryers can be extended substantially by using drying manifolds mounted directly on the unit or separately. The drying manifolds are connected to the freeze dryer unit by flanges on the unit provided for this purpose, or by vacuum hoses or vacuum pipes. Containers such as ampoules, vials, bottles, wide-neck flasks, round-bottom flasks, etc. can be fitted on the drying manifolds, depending to their construction. Continuous operation is enabled by three-way rubber valves between the single containers and the drying manifold.

Pilot freeze dryer systems – Best of process optimization