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K750X Peltier-Cooled EM Freeze Dryer

The K750X EM Freeze Dryer operates at rotary pump vacuum using a ‘Peltier’ thermoelectric stage. This means drying temperatures of down to -60°C can be achieved, enabling careful sublimation of frozen specimens under vacuum.
Key features
  • Thermoelectric cooling and heating - accurate temperature control
  • Peltier cooling/warming stage - simple and convenient to use
  • Menu-driven operation - intuitive, easy to set up and run
  • Automatic drying cycle - unattended operation
  • Extended warranty option
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The K750X EM Freeze Dryer operates at rotary pump vacuum using a ‘Peltier’ thermoelectric stage. This means drying temperatures of down to -60°C can be achieved, enabling careful sublimation of frozen specimens under vacuum. 

The freeze drying method 

Freeze drying specimen preparation reduces the distortion and shrinkage effects that occur when a wet specimen dries by normal evaporation. Distortion is due to the forces of surface tension that occur when going from a liquid to a vapour phase, such as from water to water vapour - the normal situation with biological specimens. The freeze drying method overcomes this problem by careful sublimation of frozen specimens under vacuum - a process that avoids the liquid phase and thereby reduces distortion effects. The rate of sublimation is a function of temperature and vacuum, with typical drying times being several hours or longer.


Achieving results

Ideally, freeze drying should be carried out at temperatures below the recrystallisation point of ice, but this would require very long drying times. In practice temperatures of -60°C (if back-up water cooling at 15°C is used – see: E4860 heater/chiller option) have been found to give reasonable results under vacuum levels that are achievable with a two-stage rotary vacuum pump.

For some delicate specimens, however, it is necessary to dry at temperatures below -80°C with lower sublimation rates. This requires better vacuum than can be obtained using a rotary vacuum pump alone and the lower temperatures associated with liquid nitrogen. For such applications the liquid nitrogen-cooled, turbomolecular-pumped K775X is recommended.


The technique

Both the temperature and process time can be pre-selected and the drying cycle completed automatically. Provision is made at the end of the drying cycle to allow specimens to be warmed prior to embedding. Disposable desiccant containers are positioned in the preparation chamber to enhance water vapour removal. Additionally, with a suitable container (e.g. a polystyrene pot), the vacuum chamber can be used to prepare ‘slushy’ liquid nitrogen for fast-freezing specimens prior to freeze drying.


This product is for Research Use Only.

K750X Peltier-Cooled EM Freeze Dryer


Pumping requirements

130345 m3/hr Pfeiffer DUO 6 two-stage rotary vacuum pump with oil mist filter.


Options

E48600.2 HP Recirculating Heater/Chiller (400 W) with high pressure pump.

EK4180. Stand-alone liquid nitrogen slushing chamber. Requires an additional rotary pump, e.g. 13034).

Requirements 

The K750X requires a suitable rotary vacuum pump - see: Ordering Information


Options and Accessories 

E4860 Recirculating Heater/Chiller


Specifications

Weight and dimensions. 450 mm W x 350 mm D x 175 mm H. Weight: 18 kg.

Work chamber. Borosilicate glass 165 mm Ø x 125 mm H.

Safety shield. Polycarbonate cylinder.

Timer. 0-999 hours.

Specimen stage: -60ºC to +60ºC.

Temperature controller and monitor. -90ºC to +90ºC, display resolution to 0.1 C.

Vacuum gauge range: atmosphere to 1 x 10-2mbar.

Vacuum pump (order separately): 50 L/m or greater (see: 13034). Range to 10-2mbar.

Water cooling. water cooling at nominal 15ºC (E4860 Recirculating Heater/Chiller recommended).

Electrical supply. 230 V/50 Hz (6 A maximum including pump),115 V/60 Hz (12 A maximum including pump).

Supplied with: vacuum hose and connectors, moisture trap and operating manual.