| 摘要 |
<p>942,052. Waveguide seals. PHILIPS ELECTRICAL INDUSTRIES Ltd. March 21, 1960 [March 24, 1959], No. 9906/60. Heading H1W. A vacuum-tight seal is formed in a copper waveguide or waveguide flange 1 by placing a thin mica plate 4 in a rabbet 3 formed in the solid copper of the waveguide and sealing it in the rabbet at a temperature above 500‹ C. by means of a vitreous material having a strain point lower than 400‹ C. and a coefficient of expansion greater than 80.10<SP>-7</SP>. A suitable sealing material is the glass known as Corning No. 7570 (" Corning " is a Registered Trade Mark). This glass has a strain point of 350‹ C. The glass 5 in powder form is mixed with a binder and deposited around the edges of the mica plate. The whole assembly is heated to 525 ‹ C. for half an hour and then progressively cooled to room temperature. It has been found that the pressures which occur during cooling below 350‹ C. are insufficient to damage the mica plate. It is stated that temperatures of 325‹ C. or, in certain cases up to 450‹ C., may be used in subsequent degassing operations.</p> |
