| 摘要 |
679,111. Glass manufacture. PHILIPS LAMPS, Ltd. July 4, 1946 [April 16, 1942], No. 20015/46. Class 56. [Also in Groups XI and XL (a)] A method of filling a vessel 1 provided with a glass exhaust tube 3 with gas at a pressure exceeding that of the surrounding medium comprises four steps. First the vessel is filled with gas at the pressure of the surrounding medium and then exhaust tube 3 is heated until its inner surface becomes adhesive; this may be done by heating with gas jets 4. Then the outer surface of the tube is cooled, if necessary, by an air blast 7 until it is no longer plastic; finally the vessel is filled with gas at the operating pressure and the exhaust tube is pinched together by the tongs 5 so that the inner surfaces adhere. The tube may be drawn out slightly either before or during the pinching operation. The tongs 5 should be of material having low thermal conductivity such as chrome iron. An alternative method of heating uses a heating element inside the exhaust tube so that the inner surface alone is heated; the element may be heated by high frequency induction or by a resistance element and is normally removed before pinching, but if it is a metal rod heated by high frequency it may be left in position and sealed to the glass. Specification 406,185, [Group XI], is referred to.
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