Study On A High Pressure Argon Throttle Cyosurgery Apparatus

Cryosurgery employs low temperature freezing method to destroy the lesion tissues, and to realize the target of the treatment of cancer and other diseases. The gas throttle type treatment instruments are simple in structure and are convenient in operation. They can be used in combination with B ultrasound, CT and MRI technology to achieve precise surgery.In this thesis, based on wide survey of crosurgery instrument and "argon helium knife", theoretical and experimental researches were carried out about a crosurgery apparatus utilizing high-pressure argon throttling.The main contents were as follows:1、theoretical and experimental studies were done about the effect of external precooling. Reduction of inlet argon temperature can lead to the improvement of refrigeration capacity.If inlet argon is cooled from290K to274.5K, the refrigeration capacity will increase from16.0W to22.3W.2、steady and transient physical models were established. The cryoprobe was simulated and designed. The size of the cryoprobe was optimized.3、a cryoprobe with5mm diameter was manufactured and tested with a self-made device. The length of internal heat exchanger is10cm, and the fins were made of0.2mm diameter copper wire. At ambient temperature18℃, the refrigerating capacity could reach26.3W when inlet pressure was kept at20MPa. An ice ball with about3cm diameter could be formed in water bath at room temperature18℃when inlet pressure was kept at18MPa.4、the impacts of inlet pressure and temperature on refrigeration capacity were experimentally investigated. When inlet argon temperature kept constant290K and inlet pressure increased from15MPa to20MPa, the refrigeration capacity would increase by59%or so. When inlet argon pressure kept constant19MPa and inlet temperature decreased from294K to274K, the refrigeration capacity would increase by about24%. 5、numerical simulation was carried ou for the manufactured cryoprobe. The results were compared with experiments. Good consistence was found between them on the effects of inlet temperature and pressure.