| 摘要 |
A cryogenic surgical apparatus using a Sterling-cycle refrigerator connected by elongate flexible conduits to a cryosurgical device having an operating probe. The refrigerator includes a compressor having first and second cylinders with pistons positioned therein. The cryosurgical device includes a housing defining an expansion cylinder. An expansion piston and seals are positioned within the cylinder in such manner that first and second distinct expansion spaces are defined between opposite ends of the piston and ends of the cylinder. The operating probe is connected to or positioned on the end of the housing closest to the first expansion space. A regenerator is positioned in the end of the expansion piston closest to the first expansion space and has an outlet communicating with the first expansion space and an inlet communicating with a space intermediate the two expansion spaces. First and second flexible conduits connect the first and second cylinders of the refrigerator, respectively, to portions of the housing in communication with the inlet to the regenerator and the second expansion space. The first cylinder has a larger cross-sectional area than the second cylinder so that the operating probe is cooled when the compressor rotates in a first direction and is heated when the compressor rotates in an opposite direction. The phase relationship between the two pistons of the refrigerator is selected in such manner that movement of the expansion piston in a direction from the first towards the second of the two expansion spaces is opposed by an increasingly large pressure in the second expansion space.
|
