SU4189A1 - A method for producing joints between glass and metal, especially for inserting high current conductors into hollow tubes and the like. appliances - Google Patents

Description

The difficulty of making connections between glass and metal is that the expansion ratio of the metal is different from the expansion ratio of the glass; The close contact between the two materials in the hot and cold state, necessary for perfect density, is almost incompatible with good bond strength, which would enable it to withstand without cracking, breaking the materials or putting up temperature variations that the joint inevitably undergoes. According to the invention, to fuse a glass tube with a metal one, proceed as follows: the end of the metal tube is shaped C | Easy conical socket with a relatively small wall thickness. The inner surface of this conical socket is coated with some known method with enamel, for example, acting on this surface with a mordant (for cleaning from oxides), and then covering it with enamel, which has a suitable coefficient of expansion. A glass tube (which must be of sufficient thickness to provide good mechanical strength) is inserted into this conical socket, with a ring of fusible glass welded to it at a certain distance from the end of the tube. The diameter of this ring is designed so that in the cold it hardly enters the widest part of the conical socket; on the contrary, the diameter of the glass tube is chosen so small that it passes freely even into the narrowest part of the cone. The conical bell is heated and subjected to pressure, under the influence of which the assembled parts are pressed against each other. The fusible glass that makes up the ring is softened, the glass tube penetrates further into the metal tube, and the conical shape of the end socket of the latter causes the ring of fusible glass to flatten and adhere to the enamel. In this form, the compound is ready and is quite dense. Drying is recommended in a drying chamber, but it is not necessary for small diameter joints. The cooling conical flare compresses the glass, since it has a higher expansion coefficient, but if the glass tube has sufficient wall thickness, it withstands pressure, so that the elastic metal itself is subjected to stretching. Even greater resistance of the glass tube is achieved when a ring of fusible glass is reinforced not at its end, but to some distance from this end, since in this case the shearing force acting on the tube is distributed into sections, the better the resistance torsional deformations. A ring of fusible glass also contributes to the thickening of the glass tube and, consequently, to an increase in its resistance to compression by the metal tube. The mordant must be selected so that it is well superimposed on the metal of the tube, the enamel used must correspond to this mordant and fusible glass, the choice of which must be coordinated with the grade of glass used to make the tube.

The present invention is not limited to the special case of its use and the special form of implementation indicated above as an example. In particular, instead of broadening the metal tube

for inserting a glass tube into it, the latter is narrowed at the end in the form of a truncated cone, while the metal tube is left throughout its length of the same outer diameter.

FIG. 1, 2, 3, 4 and 5 depict various applications of the proposed method.

FIG. 1 and 2 figures / and 2 are marked with glass and metal tubes, between which a tight and firm connection must be ensured; 3-end of a metal tube, having a smaller wall thickness and provided with a layer of / from enamel on the inner side. a glass tube / and the end 3 of a metal tube / is placed a ring 5 of fusible glass, which is flattened out between these deum tubes when parts / and 2 come together; while the end 3 of the metal tube is heated, for example, by pa lnik. The ring 5 can be attached either to the tube / or to the tube 3 before these parts come together; it is recommended to attach it to the handset / when using the variant of FIG. Tick tube 2-when applying the variant of FIG. 2. In all cases, however, the ring must be located at some distance from the end of the tube.

In the case of the embodiment according to FIG. 2, the tube 2 does not have a conical socket at the end 3, as in FIG. 1, but retains its cylindrical shape, while the glass tube / is tapered at the end so that it can be inserted into the tube 2.

The second variant of the invention described below relates to the case of the latter, when it is required to ensure a tight insertion of the insulated conductor inside the shell from which the air is pumped out or within which there is a gas or vapor pressure. Such an input is particularly difficult to carry out and maintain in a dense state, mainly when the conductor is intended to pass a relatively high current,

It has a significant diameter and is subject to large fluctuations in temperature. This second variant is applicable, in particular, to the device of high-power devices with thermoelectric emission, such as rectifiers, generators, high-frequency oscillations, etc. In this case, it is arranged around a conductor that is welded or otherwise formed on it. a cap that connects to a glass tube or equivalent insulating material, using such a cap in the manner explained at the beginning of the description. The glass tube is welded to the main body of the vessel forming the evacuated cavity and consisting of metal or glass. In the latter case, this tube should be stretched from the vessel wall itself.

According to FIG. 3, around the conductor / formed cap 2; This cap can be obtained in any suitable way (by stamping or the like) from the very mass of the conductor / or can be attached to it by electrical, autogenous or other welding and consist of the same or of another metal. The cap is connected to the tube 5 made of glass or another equivalent insulating material by the proposed method. The glass tube may form part of the hollow shell or may be attached to the main body of the shell by welding, if the material of this body is glass or rschuchsnnnoe caves: G11O, or osprempum o6 |); : toi iiiuivt tight fit. FIG. 4 conductor / surrounded by a cap 2, which is mounted on the insulating tube 3; the cap 2 is provided with a tubular part 4, through which the conductor 1 passes, which allows to transfer the welding location of the cap with the conductor to the end 5 of the tubular part 4. Such a device represents some npe-j property, for example, it makes it possible to install the conductor / and electrodes, which can be connected to it inside a closed shell, regardless of the formation of a connection between cap 2 and tube 3. In this case, there may be a field. A pin will fix) the stationary conductor / in tube 4 by pressing-off device f After the relative position of the parts has been established Further, the device of FIG. 4 represents the advantage that it allows the conductor 1 to be made of a very good conductive metal (copper, silver, aluminum), without paying attention to its spreading factor, which can be much larger than the corresponding glass coefficient, whereas cap 2 may be made of chromium iron or another metal suitable for forming an extremely dense bond with glass.

According to FIG. 5, a tight entry consists of a conductor / in the form of copper wire or braided cord and from a covering nozzle or cap 2, for example, from steel or chromium iron with a conical part 2 and a cylindrical part 5; the conductor / welded or sealed with the cylindrical part 5, and the glass tube 3, on which the ring of glass or fusible material 6 is fixed, is pushed into the funnel 2 using heating, as described above.

I Subject of the patent.

I. The method of obtaining joints between glass and mstl, features for the introduction of high current conductors into hollow tubes, etc., characterized in that the cylindrical or conical glass part provided at some distance from the edge with a ring of fusible glass t in another, covered on the inner surface with enamel soldering, conical or cylindrical