Freeze
Drier and Turbo Freeze Drier

EMS 750 Freeze Drier
What is FREEZE DRYING?
The application of freeze drying for specimen preparation for TEM and SEM is a well established practice.
Its application is to reduce the distortion which occurs when a wet specimen dries by normal evaporation. This distortion is due to the forces of surface tension going from a liquid to vapor phase such as water to water vapor, commonly the situation in a Biological Specimen. However, if we freeze the specimen and maintain it frozen, then by applying a vacuum, we can obtain a situation where we can remove the frozen water by sublimation, avoiding the liquid phase, and reducing the distortion. This rate of sublimation is very much a function of temperature and vacuum, and associated drying time which is in the order of several hours or longer. Ideally, freeze drying could be carried out at temperatures below the recrystallization of ice, which will require an inordinately long drying period. In practice, temperatures of -60°C have been found to give reasonable results under vacuums achievable with two stage rotary pumps, having ensured that good, fast freezing of the specimen has been carried out initially.
The EMS 750 Freeze Drier operates at rotary
pump vacuum using a 'Peltier' Thermoelectric stage, with drying temperatures
of the order of -60°C, with back-up water cooling at a nominal 15°C.
Both the Temperature and the Timer can be pre-selected, and the drying
cycle will be completed automatically. Provision is made at the end of
the drying cycle to allow the specimen to assume room temperature, or
be subsequently warmed prior to embedding. Disposable desiccant containers
are located in the preparation chamber to enhance the water vapor removal,
and with a suitable container, the vacuum chamber can be utilized to
prepare liquid nitrogen 'slush' for fast freezing.
Features
- Thermoelectric cooling and heating
- Convenient to use cold stage
- Accurate temperature and time monitoring and control
- Automatic drying cycle
- Modular electronics
- Clean line design
- Polycarbonate safety shield
Specifications
| Instrument Case | 450mm(W)x350mm(D)x175mm(H) |
| Work Chamber | Borosilicate Glass: (H) 165mm(Dia.)x125mm |
| Weight | 18Kg |
| Specimen Stage | -60°C to +60°C |
| Vacuum Gauge | ATM to 1 x 10-2 mbar |
| Temperature Controller & Monitor | -90°C to +90°C Display Resolution to 0.1°C |
| Timer | 0-999 Hours |
| Supply | 115 volts 60 Hz (12 amp Max incl pump) 230 volts 50Hz (6 amp Max incl pump) |
| Services | Water Cooling at nominal 15°C |
| Vacuum Pump (Recommended) | Complete with vacuum hose and oil mist filter 85L/Min |
| Size | 470mm(L)x150mm(W)x250mm(H) |
| Weight | 20Kg |
Ordering Information
| 91080 | EMS 750 Freeze Drier complete with accessories | POR | Request Quote |
| 91005 | Rotary Vacuum Pump | $2,306.00 | Add to Cart |
Replacement Parts
| 91013 | Glass cylinder 165mm (6") | $175.00 | Add to Cart | |
| 91014 | "L" Gasket to suit 165mm ( 6") cylinder) | 1 pair | $95.00 | Add to Cart |
| 91085 | Desiccant Containers (set of 3) | $10.00 | Add to Cart | |
| 91086 | Slushing pot |
Optional Accessories
| 91040 | EMS 250 Carbon Coating Attachment | POR | Request Quote |
| 91082 | EMS 350 Sputtering Attachment | POR | Request Quote |
For more information on Freeze Drying, please see Freeze Drying Principles.

EMS 775 Turbo Freeze Drier
FREEZE DRYING:
The application of freeze drying for specimen preparation for TEM and SEM is a well established practice.
Its application is to reduce the distortion which occurs when a wet specimen dries by normal evaporation. This distortion is due to the forces of surface tension going from a liquid to a vapor phase such as water to water vapor, commonly the situation in a Biological Specimen. However, if we freeze the specimen and maintain it frozen, then by applying a vacuum, we can obtain a situation where we can remove the frozen water by sublimation, avoiding the liquid phase, and reducing the distortion. This rate of sublimation is very much a function of temperature and vacuum, and associated drying time which is on the order of several hours or longer. Ideally freeze drying could be carried out at temperatures below the recrystallization of ice, which will require an inordinately long drying period. In practice, temperatures of -60°C have been found to give reasonable results under vacuums achievable with two stage rotary pumps, having ensured that good, fast freezing of the specimen has been carried out initially.
For particular
applications, however, it can be necessary to freeze dry at temperatures
below -80°C with lower sublimation rates for delicate specimens.
This requires a better vacuum than can be obtained using a rotary vacuum
pump.
The EMS 775 Turbo Freeze Drier operates at temperatures down to -140°C and employs a Turbomolecular pumping unit, backed by a Rotary Vacuum pump.
The lower temperatures are achieved by using a Liquid Nitrogen fed Cold Stage.
The pre-frozen specimens are admitted into the cooled stage of the drying chamber through a vacuum gate valve which interfaces to the specimen transfer chamber.
The system incorporates both Time and Temperature Control, and at the end of the drying period, the stage may be heated prior to specimen removal. The system also has facilities for purging with Nitrogen Gas.
For extended drying periods, an auto top-up device can be provided as an option to continuously 'fill' the chamber's liquid nitrogen dewar.
The option of a custom designed specimen freezing chamber to produce 'slushy' sub cooled liquid nitrogen is available which also interfaces to the specimen transfer chamber.
The option for a carbon coating attachment to carbon coat without breaking a vacuum is available.
Features
- Programmable multi-segment sequence control with 10 times and 10 temperatures
- Built in penning head and gauge
- Liquid Nitrogen fed cold stage
- Vacuum gate valve to chamber
- Vacuum specimen transfer chamber
- Accurate time and temperature monitoring
- Modular electronics
- Clean line design
- Polycarbonate safety shield
Specifications
| Instrument Case | 450mm(W) x 350mm(D) x 175mm(H) |
| Work Chamber | Borosilicate Glass: 165mm(Dia.) x 125mm(H) |
| Plus Stainless Steel Base | 110mm(Dia.) x 115mm(H) |
| Weight | 42Kg |
| Specimen Stage | -140°C to +40°C |
| Temperature Monitor | -140°C to +40°C |
| Sequence Controller | 10 times; 10 temperatures |
| Timer | 0 to 999 Hours |
| Vacuum Gauge Range | 1 x 10-2 mbar to 1 x 10-7 mbar |
| Operating Vacuum | 1 x 10-2 mbar to 1 x 10-5 mbar |
| Cooling | By liquid nitrogen conductive cooling from 1 liter dewar fitted to the chamber of the unit. |
| Turbomolecular Pump | 60 litres/Second(Ultimate vacuum 1 x 10-6 mbar) |
| Chamber Dewar | 1 Litre Capacity |
| Supply | 115 volts 60Hz (12 amp Max incl pump) 230 volts 50Hz (6 amp Max incl pump) |
| Vacuum Pump (Recommended) | Complete with vacuum hose and oil mist
filter 85L/Min |
| Size | 470mm(L) x 150mm(W) x 250mm(H) |
| Weight | 20Kg |
Ordering Information
| 93123 | EMS 775 Turbo Freeze Drier complete | POR | Request Quote |
| 91005 | E2M5 Rotary Vacuum Pump | $2,306.00 | Add to Cart |
Replacement Parts
| 91013 | Glass Cylinder 165mm (6") | $175.00 | Add to Cart |
| 91014 | "L" Gaskets to suit 165mm (6") 1 pair | $95.00 | Add to Cart |
| 90032 | Copper Discs 10/pack | $250.00 | Add to Cart |
| 90034 | Aluminum Planchettes (1") 100/pack | $18.00 | Add to Cart |
Optional Accessories
| 95128 | EMS 170 Slushing Chamber | POR | Request Quote |
| 95127 | EMS 175 Auto Top Up Unit +Controller | POR | Request Quote |
| 91040 | EMS 250 Carbon Coating Attachment | POR | Request Quote |
| 91082 | EMS 350 Sputtering Coating Attachment | POR | Request Quote |
For more information on Freeze Drying, please see Freeze Drying Principles.

