Browse Prior Art Database

Ceramic to Metal Vacuum Seal

IP.com Disclosure Number: IPCOM000093006D
Original Publication Date: 1967-Apr-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 29K

Publishing Venue

IBM

Related People

Arfman, KD: AUTHOR [+3]

Abstract

The vacuum-tight seal is located between ceramic tube 20 and metal fitting 21. The seal is made by providing very smooth surfaces at the joint of a modified stainless steel fitting and an end of a ceramic tube and the cooperation of two gold 0-rings 22 and 23. By selecting the proper materials, joints which are satisfactory for use with corrosive gases or liquids and joints to be used at high temperatures can be made by this method.

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Ceramic to Metal Vacuum Seal

The vacuum-tight seal is located between ceramic tube 20 and metal fitting
21. The seal is made by providing very smooth surfaces at the joint of a modified stainless steel fitting and an end of a ceramic tube and the cooperation of two gold 0-rings 22 and 23. By selecting the proper materials, joints which are satisfactory for use with corrosive gases or liquids and joints to be used at high temperatures can be made by this method.

The connection is made by adapting a standard one inch diameter stainless steel fitting 21 to accomodate soft gold 0-rings 22 and 23. The front ferrule 24 of the fitting is shortened to take ring 23. The two gold 0-rings of one inch I. D., with
0.020 inch and 0.040 inch cross-sectional diameters, are made and placed in the modified fitting as shown. One end of a full one inch diameter alumina tube 20 is ground on a diamond wheel to a diameter of 1.004 +/-0.005 inches to a smooth finish. Fitting 21 and ferrules 24 and 25 are remachined very slightly on a lathe to remove any scratches. The improved fitting is placed on ceramic tube 20 and compression nut 26 is moderately tightened. The resultant connection is vacuum tight and remains so even when dismantled and reassembled.

This method takes advantage of the very high strength of ceramic 20 under compressive loading. The grinding of the ceramic to a smooth surface finish serves a dual purpose. Firstly, it reduces leakage through surface scratches. Secondly,...