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The K850 CPD with Thermoelectronic Heatinhg & Adiabatic Cooling      

Critical Point Drying (CPD) 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 +347oC 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.

The K850 Critical Point Drier 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 thermoelectronic heating and adiabatic cooling and temperature control of +5oC cooling and +35oC 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 meniscus for the correct level when initially filling the chamber.

Features:

  • Vertical Chamber with Top Filling and Bottom Draining.

  • Normal Operating Temperature 35oC Pressure 1350 psi. (Crit. Temp. 31oC Crit. Press. 1100 p.s.i.

  • Adiabatic Cooling and Thermoelectric Heating.

  • Fine Control Needle Valve Pressure Letdown (Flow Gauge Monitor Option)

  • 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.

Specifications of the K850 CPD:

Instrument Case -450mm W x 350mm D x 175mm H
Weight -12Kg
Specimen Chamber - 32mm Dia x 47mm High Internal (Tested to 3000 psi)
Temperature Gauge -0-120oC
Thermal Cut-Out -40oC
Pressure Gauge -0-3000 psi
Pressure Safety Cut Out -At 1700 psi
Cooling/Heating - +5oC to +35oC
4 x On/Off Valves -Cool/Fill/Out/Bleed
1 x Needle Valve Letdown -Fine Bleed - (In Series With Bleed)
Includes: -1 x Specimen Holder Stainless Steel (12 compartments 8mm x 8mm) -10 x PTFE Pourous Specimen Pots (18mm x 14mm Pack 10)
NOTE: -Flow Guage Monitor option fitted externally in series with fine bleed.(0-2.2L/Min - CP03266-18)

Services -CO2 gas cylinder (local supply)
high pressure hose for direct connection (included with Instrument)
Electrical Supply - 230 Volts 50Hz (3 Amp max.)
115 Volts 60Hz (6 Amp max.)

ÁREAS DE TRABAJO:

Equipos de  preparación de Muestras:
Material de Microscopia Electrónica
Material General de Laboratorio

Materiales de Referencia Certificados

Microbiología

 Standards

Accesorios IR

Control de Calidad

Analizadores de NIR

FEDELCO, S.L.      C/ Lago Constanza, 46  28017 MADRID      TEL: 91 408 16 25      FAX: 91 408 16 90       E-mail: informacion@fedelco.com       Web: www.fedelco.com