K850 Critical Point Dryer with Thermoelectric Heating and Adiabatic Cooling

The K850 Critical Point Dryer is designed for use with CO2, having first replaced any water in the specimen by a series of dehydration, 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 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 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, with a side viewing port to locate the miniscus for the correct level when initially filling the chamber.

The K850 is fitted with a fine let down needle as standard and flow gauge is no longer required. A separate flow meter (not included, sold separately) is available if your application requires highly accurate monitoring and/or flow control.


  • Vertical chamber with top filling and bottom draining
  • Normal operating temperature 35°C pressure 1500 psi
  • adiabatic cooling and thermoelectric heating
  • Fine control needle valve pressure letdown
  • 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 pressure relief valve and rupture disc protection
  • Polycarbonate safety shield


Instrument Case 450 mm (W) x 350 mm (D) x 175 mm (H)
Weight 12 kg
Specimen Chamber 32 mm (D) x 47 mm (H)
(Tested to 3000 psi)
Temperature Gauge 0-120°C
Thermal Cut-Out 40°C
Pressure Gauge 0-3000 psi
Pressure Relief At 1500 psi
Rupture Disc At 1900 psi
Cooling/Heating +5°C to +35°C
Two On/Off Valves Inlet/Outlet/Cool/Vent
Needle Valve Letdown
Supply 115V 60Hz (6 Amp Max)
230V 50Hz (3 Amp Max)
Services Requires CO2 gas cylinder direct connection
by high pressure hose. (High pressure hose
included with instrument.)

Ordering Information

Cat # Description Pack Price Quote Quantity
Cat #: 91090 Description: K850 Critical Point Dryer Pack: Each Price: $0.00 Add to Quote:
Cat #: 91091 Description: Mesh Basket Pack: Each Price: $291.50 Add to Quote:
Cat #: 91092 Description: Pourous Spec Pots Pack: 10 Pack Price: $198.00 Add to Quote: