Quorum Technologies own the Polaron brand, and in early 2006 they also purchased Emitech. Rationalisation of the 3 brands is well under way, but a few Emitech and Polaron instruments are still available and featured on our site.  ProSciTech is the sole distributor for these three brands in Australasia, south of Singapore. Some additional data may be available from www.quorumtech.com.

Warranty: Quorum Technologies offer a standard 12 months warranty on all instruments. This can be extended to 3 years by filling in and returning the registration form. Pumps are excluded from the extension.
Operating Principle: Critical Point Drying is so named as it includes, as part of its process, the occurrence known as the continuity of state for which there is not apparent difference between the liquid and gas state of a medium, the surface tension between this interface reducing to zero. This occurs at a specific temperature and pressure with resulting density, and is known as the Critical Point. This condition of zero surface tension can be used to dry Biological Specimens, avoiding the damaging effects of surface tension.

In biological specimens we are mainly concerned with the removal of water. Unfortunately, the critical point of water of +347°C and 3212 p.s.i. is inconvenient, and would cause heat damage to the specimen. The most common and convenient transitional medium for critical point drying is carbon dioxide CO­2­ which has its critical point at 31oC and 1072 p.s.i. However, it is not miscible with water, and therefore we have to involve a third medium, commonly Acetone, which is termed the intermediate fluid. We can now convert our transitional fluid, typically CO­2­ from liquid to gas without surface tension at the critical point.

Critical Point Drying - a technical brief
Critical Point Drying - notes

Polaron KE3000 and KE3100

The KE3000 Series critical point dryers consist of a cylindrical, water-cooled pressure chamber, horizontally mounted, with attached gauges and shut-off valves for process control. Two models are available in the series, the KE3000 and KE3100. Both models are identical in construction, the only difference being a larger chamber fitted to the KE3100.
KE3000 features a horizontal pressure chamber measuring 30.1mm internal diameter x 82mm in length.
Where increased chamber volume is required for either the size of specimen or quantity of specimens to be dried, a large capacity model KE3100 is available. The chamber dimensions are 63.5mm internal diameter x 82mm in length giving approximately three times the volume of the KE3000.

  • Proven reliability - over 6,000 critical point dryer installations world-wide.
  • Simple robust construction - easy to maintain, many critical point dryer users carry out their own routine maintenance.
  • Horizontal chamber and large viewing window - gives excellent visibility of the critical point drying process and of the fluid level in the chamber. Unlike many of the more complex critical point dryer designs it is much easier to see the phase change at the critical point.
  • Large robust valves for ingress of CO2, draining of fluids and venting of gas. Very durable. The rapid ingress of CO2 helps prevent pre-drying of samples.
  • Safety - every critical point dryer is independently pressure tested to 2500psi. A certificate is issued. A pressure bursting disc is fitted to safeguard against misuse.
  • Sample handling - optional sample holders for coverslips and TEM grids. Porous pots are available for very small samples.

Optional Accessories:
  • E4860 /240V - Recirculating heater/chiller 0.2HP (400 watts) + pressure pump
  • E4860 /110V - Recirculating heater/chiller 0.2HP (400 watts) + pressure pump
  • E3500 /240V - Thermocirculator (heating only ambient to 60°C)



Critical point dryer, standard
Critical point dryer, large chamber
KE3500 Thermocirculator is a low cost, portable water circulating system for supplying a constant temperature supply for closed and open loop applications at near ambient to +60°C temperatures.
The thermocirculator will give controlled heating of Polaron E3000 and E3100 Critical Point Dryers. It is connected directly to the inlet and outlet of the KE3000 or KE3100 water jacket. The temperature of the circulating fluid is pre-set, typically set to 37°C (e.g. just above the critical temperature).
The unit is suitable for open or closed loop applications and has all controls and liquid connections on the front panel. The temperature controller shows not only the 'set' temperature (between ambient and +65°C) but also the actual liquid temperature. The fluid is circulated by a gland-less magnetic pump, through an aluminium reservoir. A cooling coil is mounted in the liquid reservoir. This coil can be directly connected to the main water supply and is primarily used when temperature control near to ambient is required. The electronic control system features a zero voltage switching unit which minimises mains electrical interference enabling the KE3500 to be used and sited with other sensitive electronic instruments.

  • Precise control of heating
  • Compact
  • Robust and reliable
  • No running water to waste
  • Ideal for use with the Polaron KE3000 / KE3100 critical point dryers

Link to Quorum Technologies

Optional Accessories
  • E4860 - Recirculating heater/chiller 0.2HP (400W) + pressure pump
  • E4860 /110V - Recirculating heater/chiller 0.2HP (400W) + pressure pump
  • E4870 - Recirculating heater/chiller 0.2HP (1400W) + pressure pump
  • E4870 /110V - Recirculating heater/chiller 0.2HP (400W) + pressure pump
  • E4880 - Recirculating heater/chiller 0.75HP (2200W) + high pressure pump
  • E4890 - Recirculating heater/chiller 1.0HP (3000W) + high pressure pump

Thermocirculator, ambient to 60°C
The K850 critical point dryer is designed for use with CO2 having first replaced any water in the specimen by a series of dehydrations, often in the same fluid such as acetone, which will also be the intermediate fluid.

(Wet specimen) - Water - Acetone - 30% - 100% - CO2 - C.P.D. - (Dry Specimen)

The specimens for critical point drying are located in the pressure chamber of the K850. The chamber is pre-cooled to allow it to be readily filled with liquid CO2 from a gas cylinder. The chamber is then heated to just above the critical temperature with a subsequent critical pressure being achieved. The CO2 gas is vented through a needle valve, to avoid specimen distortion.

The K850 is fitted with thermoelectric heating and improved adiabatic cooling and temperature control of +5°C on cooling and +35°C on heating. This ensures the critical point is accurately obtained, avoiding excess pressures or temperatures or the need to rely on pressure relief valves to control pressure during the heating cycle. The chamber is vertical, with top loading, to ensure specimens do not become uncovered during the drying process. A side viewing port shows minimum and maximum level marks and the meniscus for the correct level when initially filling the chamber.

CPD multiple specimen holder - current model
[click to enlarge]
CPD multiple specimen holder
Standard specimen holder
[click to enlarge]
Standard specimen holder - previous model
Porous specimen pots for small or delicate specimens (CPD800A)
[click to enlarge]
Porous specimen pots for small or delicate specimens (CPD800A)

  • Vertical Chamber with Top Filling and Bottom Draining.
  • Normal Operating Temperature 35°C Pressure 1350 psi. (Crit. Temp. 31°C Crit. Press. 1100 p.s.i.
  • Adiabatic Cooling and Thermoelectric Heating.
  • Fine Control Needle Valve Pressure Letdown (Flow Gauge Monitor OPTION.)
  • Illuminated Chamber with Side Viewing Port and Protective 'Lexan' Shield.
  • Stirrer System for Enhanced Solvent Exchange.
  • Temperature Monitoring and Control with Thermal Cut-out Protection.
  • Pressure Monitoring with Safety cut-out for Over Pressure.

  • Instrument....................Case 450mm(W) x 350mm(D) x 175mm(H)
  • Weight........................12kg
  • Specimen Chamber..............30mm(Dia.) x 40mm(H) (Tested to 3000 psi)
  • Temperature Gauge.............0-120°C
  • Thermal Cut-Out...............40°C
  • Pressure Gauge................0-3000 psi
  • Pressure Relief...............At 1700 psi
  • Rupture Disc..................At 1900 psi
  • Peltier Cooling/Heating.......+5°C to +35°C
  • 4x On/Off Valves..............4 x On/Off Valves - Cool/Fill/Out/Bleed
  • 1x Needle Valve Letdown.......Fine bleed (In Series With Bleed)
  • Includes......................1x Specimen Holder Stainless Steel (12 compartments 8mm x 8mm) and 10x PTFE Porous Specimen Pots (18mm x 14mm Pack 10)
  • NOTE......................Flow Gauge Monitor option fitted externally in series with fine bleed.(0-2.2L/Min - CP03266-18)
  • Services......................Requires CO2 (local Supply) high pressure hose for direct connection. (High pressure hose included with instrument)
  • Electrical....................230 Volts 50Hz (3 Amp Max.) 115 Volts 60Hz (6 Amp max.)
  • Warranty......................3 Years all parts

TEM grid hold for K850x.<br> Also available are bulk and coverslip holders

TEM grid hold for K850x.
Also available are bulk and coverslip holders
Micrograph of leg muscle of a mouse, dehydrated in alcohol, frozen fractured, thawed in alcohol, then critical point dried in Emitech K850, resin embedded. Rotary carbon and then platinum coated.

Micrograph of leg muscle of a mouse, dehydrated in alcohol, frozen fractured, thawed in alcohol, then critical point dried in Emitech K850, resin embedded. Rotary carbon and then platinum coated.
Critical point dryer
The K850WM is designed to critical point dry a complete 150mm (6") wafer.The K850WM is fitted with thermo-electric heating and adiabatic cooling and temperature control of +5°C cooling and +35°C during heating. This ensures the critical point is accurately obtained, avoiding excess pressures or temperatures, or the need to rely on pressure relief valves to control pressure during the heating cycle.The K850WM has a vertical chamber which allows top loading of specimens. A viewing port is fitted in the top plate for sample observation. The K850WM sample exchange mechanism is simple to use and ensures the sample remains under liquid during loading.

Sample handling
100mm or 150mm diameter wafers are held in a PTFE holding tray.The tray including wafer is immersed in acetone in order to remove all moisture from the sample. After dehydration, the wafer and holder is transferred into the pre-cooled sample chamber using the wafer transfer device. On completion of the critical point drying process, the wafer is removed from the chamber using the transfer device prior to further processing.

  • 170mm diameter chamber - optimised for wafer / MEMS drying
  • Vertical chamber with top filling and bottom draining - ensures specimens do not become uncovered during drying
  • Thermoelectric heating - accurate temperature control
  • Fine control needle valve pressure let down - precise control
  • Temperature monitoring and control with thermal cut-out protection
  • Pressure monitoring with safety cut out for over pressure

  • Supplied with - PTFE specimen holder (for a 150mm wafer), high pressure CO2 hose, operating manual and test certificate
  • Chamber size - 170mm internal diameter x 15mm high
  • Test pressure - 3000psi
  • Operating temperature - Normal operating temperature 35°C (critical point temperature is 32°C)
  • Operating pressure - 1350psi (critical point pressure 1172psi)
  • Pressure safety cut-out - 1700psi
  • Dimensions - W450 x D350 x H175mm
  • Weight - 12kg
  • Electrical - 230V 50Hz (3A max) or 115V 60Hz (6A max)
  • Site considerations - Requires space for CO2 cylinder
  • Requirements - E4860 Heater/chiller (for cooling chamber), EK3102 CO2 bottle heating system

Optional Accessories:
  • E4870 - Recirculating heat/chiller 0.2HP (1400 watts) + pressure pump
  • E4870 /110V - Recirculating heat/chiller 0.2HP (1400 watts) + pressure pump
  • EK3102 - CO2 conditioning system


Chamber interior with wafer

Chamber interior with wafer
Large chamber critical point dryer
Note: Our freeze dryers are designed for the freeze drying of extremely small samples for scanning electron microscopy.
We receive some inquiries for drying food or for biochemistry purposes; for that our instruments prepare samples which are too small and the instruments are too costly.
Samples for electron microscopy must be plunge-frozen so that they are vitrified - frozen extremely rapidly to achieve glass-like ice.
For best results the specimen is kept at minus 100°C during the drying process. At that low temperature ice sublimation rates, while using a rotary vane pump, are impossibly slow. For this reason we recommend the turbomolecular pumped freeze dryer. Freeze drying may offer best biological specimen preparation for SEM, but because of the expensive equipment required, most laboratories dry their specimens with supercritical CO2, using a critical point dryer.

Operating Principle: The use of freeze drying for specimen preparation for TEM and SEM is a well established practice. Freeze drying is used to reduce the distortion that occurs when a wet specimen dries by normal evaporation. This distortion is caused by the forces of surface tension going from a liquid to a vapour phase. In biological specimens this is commonly water to water vapour. If the specimen is frozen and maintained in a frozen state and vacuum is applied, the frozen water can be removed by sublimation. This avoids the vapour stage and reduces the distortion.

PUMPS: All freeze dryers require an appropriately sized, two stage mechanical pump. Turbo pumped instruments include the turbo pump, but also require a mechanical pump. We supply suitable pumps for our preparation instruments and for other purposes. Inquire for more information.


The Emitech K­750X operates at a rotary pump vacuum using a "peltier" thermoelectric stage with drying temperatures in the order of ­-60°C, with backup cooling at a nominal -15°C. Both the temperature and timer can be pre­selected and the drying cycle will be completed automatically. Provision is made at the end of the drying cycle to allow the specimen to reach room temperature or be subsequently warmed prior to embedding. Disposable desiccant containers are located in the preparation chamber to enhance the water vapour removal and with a suitable container, the vacuum chamber can be utilised to prepare liquid nitrogen "slush" for fast freezing.

  • Thermoelectric cooling and heating
  • Convenient to use cold stage
  • Accurate temperature and time monitoring and control
  • Automatic drying cycle
  • Modular control electronics
  • Clean line design

  • Instrument case....................450mm(W) x 350mm(D) x 175mm(H)
  • Work chamber.......................Borosilicate glass 165mm(dia.) x 125mm(H)
  • Weight.............................18kg
  • Specimen stage.....................-60°C to +60°C
  • Vacuum gauge.......................ATM ­1 x 10-2 mbar
  • Temperature controller & monitor...-90°C to +90°C Display resolution to 0.1°C
  • Timer..............................0-999 Hours
  • Supply.............................­230/240 volts 50 Hz (6 amp max incl pump)
  • Services...........................Water cooling at nominal 15°C
  • Vacuum pump (recommended)..........E2M5 complete with vacuum hose and oil mist filter 85L/Min
  • Size...............................470mm(L) x 150mm(W) x 250mm(H)
  • Weight.............................20kg

Optional Accessories
  • Rotary pump - See page V4 and K6 + oil mist filter
  • E4860 /240V - 0.2HP chiller heater (400 watts) + pressure pump
  • E4860 /110V - 0.2HP chiller heater (400 watts) + pressure pump
  • EK3125 - K350 Sputter coating attachment
  • SC7640-CF - Carbon fibre attachment (includes power supply)
  • SC7640-CR - Carbon rod attachment (includes power supply)

Peltier freeze dryer


The Emitech K­775X operates at temperatures below ­80°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 instrument 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.

  • Liquid Nitrogen fed Cold Stage
  • Vacuum Gate Valve to Chamber
  • Accurate Time and Temperature Monitoring
  • Modular Electronics
  • Clean Line Design

  • 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..............-120°C to +40°C
  • Temperature Monitor.........-120°C to +40°C
  • 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
  • Turbomolecular Pump.........50 litres/Second (Ultimate vacuum 1 x 10-6 mbar)
  • Chamber Dewar...............1 Litre Capacity
  • Supply......................230/240 volts 50Hz (6 amp Max incl pump)
  • Vacuum Pump (Recommended)...E2M5 complete with vacuum hose and oil mist filter. 85L/Min
  • Size........................470mm(L) x 150mm(W) x 250mm(H)
  • Weight......................20kg

Optional Accessories
  • Rotary pump - See page V4 and K6 + oil mist filter
  • EK3125 - K350 Sputter coating attachment
  • SC7640-CF - Carbon fibre attachment (includes power supply)
  • SC7640-CR - Carbon rod attachment (includes power supply)
  • EK4100 - Auto top up unit with 60L pressurised Dewar
  • EK4180 - Slushing chamber

Turbo LT freeze dryer