METHOD AND DEVICE FOR EVACUATION OF CRYOGENIC INSULATION Russian patent published in 1997 - IPC

FIELD: methods for evacuation of cryogenic insulation. SUBSTANCE: cryogenic insulation is evacuated from atmospheric pressure P_atm to pressure of triple point P₁ at constant rate of evacuation. As soon as pressure P₁ has been obtained, chamber is blow with dry gas, thus stabilizing the pressure. After satisfying relationship P₁< 2P₂ where P₁ is pressure of moisture triple point, Pa; P₂ is pressure in cryogenic insulation without taking into account moisture vapors, Pa, blowing the chamber with gas is discontinued and chamber is evacuated to working pressure. Device for realization of this method includes vacuum gauges, nitrogen trap, shut-off valve, dry fixed gas source, orifice whose carrying capacity is equal to rate of evacuation at pressure P₁. Evacuation of cryogenic insulation is effected by means of vacuum pump. EFFECT: enhanced efficiency. 3 cl, 2 dwg, 1 tbl