Semi-automatic critical point drying apparatus

摘要

A semi-automatic critical point drying apparatus for the preparation of biological or organic specimens for examination thereof by scanning electron microscopy. In the preparation of such specimens, the specimen is placed in a chamber into which is introduced a transitional fluid, such as liquid CO2, which replaces the dehydrating liquid in the specimen as a part of the drying process. In critical point drying, the transitional fluid in the chamber is heated to elevate the chamber temperature and pressure above the critical point of the fluid. A five-way indicator valve replaces the manually adjustable valve of prior art apparatus for enabling the operator easily to control the cooling, filling, purging and bleeding operations of such a critical point drying apparatus.