| 摘要 |
A cryosurgical instrument having a purge cycle of indeterminate duration, separate and apart from its cooling and warming modes, which can be conducted with a refrigerant consisting of a low pressure unsaturated or saturated gas. During the purge cycle, the pressure of the refrigerant gas is regulated to a level below that which is required to effect a Joule-Thomson expansion of the gas upon its entrance into an expansion chamber adjacent the tip of the instrument while simultaneously exhausting the effluent to the atmosphere through an exhaust valve actuated by a footswitch.
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