High vacuum device

Claim 1

AN IMPROVED CONSTRUCTION OF A FRACTIONATING, HIGH VACUUM OIL DIFFUSION PUMP, EQUIPPED WITH A COLD CAP COMPRISING IN COMBINATION: (A) A VERTICALLY ARRANGED, TUBULAR PUMP BODY AND MEANS FOR COOLING THE PUMP BODY, THE PUMP BODY BEING OPEN AT ITS UPPER END TO PROVIDE A LARGE INLET AND CLOSED AT ITS LOWER END AND HAVING AN EXIT OPENING IN ITS TUBULAR WALL NEAR THE LOWER END THEREOF, (B) A FRACTIONATING, VAPOR JET ASSEMBLY MOUNTED IN THE PUMP BODY AND HAVING A VERTICAL SERIES OF OUTWARDLY AND DOWNWARDLY FACING JET NOZZLES INCLUDING A JET NOZZLE NEAR THE TOP OF THE ASSEMBLY, THE ASSEMBLY HAVING A GENERALLY STEPPED FORM SO THAT LOWER PORTIONS OF THE ASSEMBLY PRESENT OPTICAL TARGETS TO THE SAID TOP JET NOZZLE; (C) HEATER MEANS LOCATED AT THE BOTTOM OF SAID PUMP BODY FOR PRODUCING OIL VAPORS WITHIN THE VAPOR JET ASSEMBLY; (D) A COLD CAP MOUNTED OVER THE SAID TOP JET NOZZLE IN CLOSELY SURROUNDING, YET THERMALLY ISOLATED, RELATION THEREWITH AND ARRANGED TO INTERCEPT A PORTION OF THE VAPOR JET EMERGING FROM SAID NOZZLE AND MEANS FOR COOLING SAID COLD CAP SO THAT IT CONDENSES THE INTERCEPTED VAPOR; AND (E) MEANS FOR SHIELDING THE SAID LOWER PORTIONS OF THE ASSEMBLY PRESENTING OPTICAL TARGETS TO THE TOP JET NOZZLE FROM CONDENSATION DRIPPING DOWNWARDLY FROM SAID CAP, SAID SHIELDING MEANS BEING ARRANGED SO THAT IT MAINTAINS THE CONDENSATE AT A TEMPERATURE BELOW ITS BOILING POINT.