Abstract: A cryosurgical system comprises a compressor unit and a probe assembly. A secondary refrigerant stream from the compressor unit pre-cools a heat exchanger within the probe assembly in a standby mode of operation. After the heat exchange is pre-cooled, a primary refrigerant stream can be passed through the cooled heat exchanger and thereafter expanded within a tissue-contacting portion of the probe assembly to achieve very low temperatures, typically minus 100° C. or lower. After cooling, the refrigerant stream may be passed through the probe assembly with no or partial expansion to warm the tissue-contacting surface of the probe. A probe sheath can be used to provide sterility.

Abstract: A method and device is disclosed for removing residual oil and other contaminants from the refrigerant stream flowing to low-temperature stages of a cryogenic refrigerator. A stream of vapor and liquid refrigerant is injected into a cyclone chamber ?32! through the inlet tube ?34!. While the liquid drains down a conical section ?36! and out through a liquid line ?38!, the vapor phase moves up into a packing of metal platelets ?42! which is, in a particular embodiment, cooled by a returning stream of cold vapor passing through a tube ?48! wrapped around the column. A portion of the vapor condenses on the platelets and is maintained in equilibrium with the vapor. Since high-molecular-weight contaminants are more soluble in the liquid phase, they are carried down the column with the drops of condensate and are swept out with the liquid fraction through the liquid line ?38!.