CS253608B1 - A method of making a vacuum-tight connection of a glass tube flask with a smaller diameter glass tube - Google Patents

Abstract

The purpose of the method of vacuum-tight connection of a glass pump tube with a glass bulb, especially in the production of light sources, is to maintain the permeability of the pump tube during sealing by pressing without reducing the inner diameter of the pump tube at the point of pressing. This is achieved by blowing gas through the pump tube.

Description

The invention provides a vacuum-tight connection of a glass pump tube and a glass bulb in the manufacture of a low pressure mercury vapor lamp simultaneously with the cathode system such that the glass pump tube joint of the glass bulb is vacuum-tight and the pump tube remains passable without reducing the inner diameter at the junction.

To date, the following methods of connecting a glass pump tube to a glass bulb of a light source are known. The pump tube is melted to the flask from the side of the flask or at the top of the flask, except for the electrode system melting. Another method that is applicable to very small bulb diameters, for example in miniature bulbs, is to butt weld the pump tube. Another solution is to seal the pump tube first into the light source foot together with the leads and the electrode holder. This foot is then vacuum sealed to a bulb, such as a conventional bulb. The first two methods are not applicable in the manufacture of single-ended low pressure mercury vapor lamps.

In the method of sealing the foot, it is first necessary to produce a blank - a saucer on a special device and then to make a foot with a melted pump tube from another device. Only then can the foot be connected to the flask on the other equipment.

The disadvantages of the above methods are eliminated by the vacuum-tight connection of the glass pump tube to the glass tube, with the possibility of simultaneously sealing the cathode system, pressing the open end of the flasks into which the pump tube is partially inserted. The pump tube is purged with gas while the open end of the flask is heated to the melting point of the glass.

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The advantage of the method of the sealing of the pump tube according to the invention is the elimination of the production of two blanks - the saucer foot and thus simplification of the production technology. It is also possible to use a pump tube with a larger diameter. This results in a higher pumping speed during the subsequent treatment of the light source and thus a better vacuum treatment of the entire light source. When the inert gas is used, the electrode is in a protective atmosphere throughout the heat treatment.

The method can be carried out, for example, by a sealing device comprising a collet holding collar, an electrode holder and a pump tube. This apparatus is complemented by a set of gas burners designed to heat the bottom of the flask to (glass melting fences and mechanical jaws) which, after melting the bottom of the flask, press the molten glass around the pump tube and wire electrode leads. A jaw is formed in the jaws corresponding to the outer diameter of the pump tube and axially identical to the pump tube, and cooling gas is introduced into the lower part of the pump tube.

Claims (1)

A method for making a vacuum-tight connection of a glass tube to a smaller diameter glass tube by pressing the open end of a glass bulb heated to the melting temperature of the glass into which the smaller diameter tube is partially inserted, characterized in that glass, a smaller diameter tube is purged with gas.