Abstract: A cryogenic device and a method for selectively dispensing a jet of gas or a mixture of gas and liquid cryogen particles, that is, single phase or two phase fluid, at the user's option, from a nozzle selected from a range of nozzle sizes. Pressurized liquid cryogen is supplied through an orifice to a nozzle-equipped expansion chamber also connected to a pressure regulated source of gas. A valve-controlled passage venting to the atmosphere from the expansion chamber is normally closed but, when open, is effective to reduce the chamber pressure by a major fraction of 1 psig provided the gas flow from the pressurized gas source is interrupted. The single phase gas jet dispensed in the non-venting mode substantially instantly converts to a stable two phase jet of gas and liquid particles irrespective of which one of the nozzle sizes is then in use.

Abstract: Apparatus and method for dispensing a jet of cryogenic coolant selectively in single gaseous phase and in dual gaseous and finely divided liquid phase from a self-pressurizing source of heat saturated liquid coolant. The coolant is stored under constant pressure and in a heat-saturated condition and, when needed, is partially expanded into an expansion chamber equipped with a coolant jetting orifice and a venting orifice regulatable to control coolant flow from the jetting orifice in single or dual phase. The liquid coolant is conveniently stored in a hand-held dewar flask equipped with a pressure relief valve and utilizing a relatively long, small bore passage as the coolant jetting orifice.

Abstract: A hand-held cryogenic device for and method of necrotizing and shaving live tissue having a chamber chargeable with liquid cryogen. One heat conductive wall of the chamber is adapted to be flooded with cryogen while being manipulated over the tissue and includes an opening allowing gaseous cryogen to escape in contact with the tissue. This wall is selectively effective to shave or slice away necrotized tissue.