Performance Evaluation of a Novel Liquid Nitrogen Cryoprobe

A novel liquid nitrogen cryoprobe is developed in the present study. The inlet, handle, the vapor-liquid separator and the heat transfer segment of the cryoprobe are designed to be detachable. This flexible construction provides many distinct features, such as good maneuverability, high safety and low cost. A new vapor-liquid separator is made to ensure the free flow of the liquid nitrogen and increase the probe freezing capacity. The wall temperatures at the different locations along the cryoprobe are measured in the air, gel and brine, with the various driven pressure ranging from 0.3 to 0.6 MPa. The results are compared to the other probe. It is found that the precooling time of the probe is shortened significantly. The present cryoprobe offers better cooling performance to the existing cryoprobe. The heat flux transferred from the surrounding air or brine to the cryoprobe is estimated, and it is concluded that the boiling pattern in the probe is the film boiling and suggestions for further improvement of the cryoprobe´s performance is made based on the analysis