SELF-PRESSURIZING CRYOGENIC APPARATUS AND METHOD

摘要

1531647 Surgical cooling appliances V M GREGORY 18 May 1977 [24 May 1976] 20936/77 Heading A5R [Also in Division F4] A cryosurgical appliance dispensing a stable jet of gaseous or a dual phase jet of cryogenic coolant through an outlet such as a hypodermic needle 52 from a source of pressurized liquid coolant in a Dewar flask which flows to an evaporation and expansion chamber 35 having pressure varying means. The means comprises a bleed passage 55 leading to a manually controlled outlet valve 56 and having a flow restrictive mass 63. The flask is maintained at a predetermined superatmospheric pressure by a relief valve 43 and flow to the chamber 35 is controlled by a manually operated needle valve 31.