| 摘要 |
991,398. Discharge tubes; turret machines. RADIO CORPORATION OF AMERICA. March 23, 1964 [April 2, 1963], No. 12171/64. Headings H1D and H1J. A carbon coating is produced over desired portions of the interior surface of an electron tube envelope by burning within the envelope a carbonaceous fuel deficient in oxygen, and thereafter burning off unwanted portions by a flame over-supplied with oxygen; the method permits the carbonization of the tube to be performed as one step of the process of sealing on the exhaust tubulation. The glass bulb 12 having a dome 30 and open end 24 is rotated about its axis while being indexed from station to station of a bulb tubulating machine, at the first of which the carbon coating is deposited by the introduction through end 24 of an air/acetylene gas burner. At subsequent stations, a soft and oxidizing flame polishes cut end 24 and burns off the carbon coating thereabout; a silicone rubber wiper is inserted into the bottom of the bulb to ensure complete removal of carbon; an air/hydrogen flame burns off the carbon coating on the dome 30 and preheats the latter, while an auxiliary burner preheats the lower end of exhaust tubulation 14; a needle flame punctures a hole in dome 30 and tubulation 14 is sealed thereto; the stem 16 with electron cage assembly 18 and barium getter 28 is sealed in the end 24 of the bulb; and the latter is exhausted before tubulation 14 is tipped off. Vertical movement of the burners within the bulb is sufficiently rapid to prevent the removal of the wall coating in a spiral track. |
