| 摘要 |
<p>1,206,174. Discharge tubes. SYLVANIA ELECTRIC PRODUCTS Inc. 14 Dec., 1967 [19 Dec., 1966], No. 56922/67. Heading H1D. A method of opening an evacuated electron tube having a glass envelope with a projecting seal 17, for example for replacing a defective electron gun assembly in a colour or monochrome cathode ray tube, comprises positioning the projecting seal 17 within a hermetic chamber 24, evacuating the chamber, opening the tube seal 17 to the ambient vacuum of the chamber and admitting an inert atmosphere into the chamber and tube as a gaseous fill to prevent contaminants getting into the open envelope. As shown the neck of a cathode ray tube is supported within the upper portion 25 of chamber 24 with seal 17 projecting into the lower portion of the chamber, the two parts of the chamber being connected by grooves 26 in shoulder 27 on which the neck of the tube rests. After evacuating the chamber 24, preferably to the same extent as the vacuum within the tube, the seal is opened, for example, by fluid operated piston 39 which is released by unscrewing the threaded shaft 45 attached to the piston from engagement with the wall 53; the piston then being impelled to break the seal by the pressure differential inside and outside the chamber 24. A retaining basket 59 in the lower portion of the chamber catches the pieces of the seal to prevent their being drawn into the tube. Slowly from a gas supply, the inert atmosphere is admitted, preferably into the upper portion 25 of the chamber against the neck of the tube to provide a baffle effect. The piston 39 may also be mechanically or solenoid operated.</p> |
