PHASE SEPARATION OF CRYOGEN IN CRYOSURGICAL INSTRUMENT

摘要

A cryosurgical instrument including: a shaft having a closed distal end defining an expansion chamber and a proximal end that receives an inflow of cryogen and to exhaust a flow of expanded cryogen; and a heat exchanger with a cryogen delivery tube that spirals around a core disposed along a longitudinal axis thereof. The cryogen delivery tube, where it spirals, is in fluid tight contact with the inner surface of the shaft so as to form spiraling cryogen exhaust pathways that extend along a portion of a length of the cryosurgical instrument from the distal end of the shaft The cryogen delivery tube forces a two-phase flow of cryogen to undergo phase separation by centrifugal forces and urges the liquid phase against the external walls of the spiral coil and the outer surface of the spiral gap. Heat exchanging occurs close to the external wall of the instrument.

主权项

1. A cryosurgical instrument comprising:
a shaft having a closed distal end defining an expansion chamber and an open proximal end adapted and configured (i) to receive an inflow of cryogen and (ii) to exhaust a flow of expanded cryogen; and a heat exchanger comprising:
a solid core element extending along a longitudinal axis of the heat exchanger; anda cryogen delivery tube that spirals around and contacts the solid core element, wherein the spirals of the cryogen delivery tube are spaced from each other and in fluid tight contact with the core and an inner surface of the shaft so as to form a spiraling cryogen exhaust pathway, and wherein cryogen spins as it travels through the delivery tube to the expansion chamber and as it travels around the delivery tube from the chamber.