SU1316981A1 - Method for sizing glass tubular shells - Google Patents

Abstract

The invention relates to the field of heat treatment of glass and can be used in the manufacture of glass tubular shells with a precisely defined inner diameter. In order to maintain the calibration accuracy inside the tubular glass preparation, a caliber is placed, the billet is heated to a temperature above the temperature of the beginning of glass softening at 150-200 C, after the billet is heated, the billet is heated by its own weight for a length of 2- 3, the thickness of the wall of the workpiece, then besiege the softened glass mass per caliber due to the vacuumization of the cavity between the inner wall of the workpiece and the outer wall of the caliber. 4 il. & (L with O); o CX)

Description

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The invention relates to heat treatment of glass and can be used in the manufacture of glass tubular shells with a precisely defined inner diameter.

The purpose of the invention is to improve the calibration accuracy.

FIG. Figure 1 shows the workpiece with the caliber placed in it at the time of the start of calibration; Fig. 2 is the same at the moment the billet is inserted by its own weight; Fig. 3 is the same, at the time of the deposition of a softened glass mass into a caliber due to the vacuumization of the cavity between the inner wall of the workpiece and the outer wall of the caliber; 4 is the same when the calibrated billet is cooled.

The method is presented on the example of obtaining polygonal shells for packing rigid gradient elements (gradans) with thermal diffusion

processing,

A polished hexagonal caliber 2, a circumscribed circle of which is 1410.01 m with an adapter 3, Caliber 2 assembled on a metal tube 4 and made of stainless steel. An emphasis 5 is placed under the workpiece at a distance of a, equal to 5 mm from the end of the glass tube. The upper end of a vertically open billet 1 is connected to a vacuum pump (not shown) through a vacuum-tight connection 6, Calibrated billet 1 with the assembled caliber 2 is placed in a tube furnace 7 and begins to heat to a temperature above the temperature of the beginning of softening of glass ( The temperature of the onset of softening of the glass of the TC 620 ° C) on, i.e. 800 ° C

When this temperature is reached, the workpiece 1 in the heating zone becomes softer, sits down due to the free pull under its own weight up to the stop 5 by a length equal to 2.5 wall thicknesses of the workpiece, i.e. by 5 mm.

After a certain period of time, during which the glass melting occurs, turn on the vacuum and precipitate the softened glass to a caliber on the heated section of the workpiece (Fig. 3).

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Having calibrated the section of the blank, the furnace 7 is moved down along the blank, the emphasis 5 is lowered to the required length, and the whole process is repeated.

At the end of the calibration, turn off the vacuum, cover the tubular casing to 250 ° C and remove the caliber (Fig. 4) ..

The preform 1 thus obtained has a hexagonal shape with an inner diameter of 14 ± 0.006 mm.

Heating the billet 1 to a temperature above the temperature of the beginning of glass softening at 150–200 ° C allows the glass mass to penetrate through the wall thickness due to surface tension forces, and subsequent sitting down due to shrinking under its own weight of the heated billet for a length of

equal to 2-3 thicknesses of the blank wall, allows to remove excess glass mass from the calibration zone, which eliminates the appearance of folds and, consequently, the difference in thickness of the walls

billet, and this in turn provides a tighter uniform relief of the caliber with glass melt, which ultimately improves the calibration accuracy.

Heating the billet to a temperature higher than the temperature of the beginning of glass softening more than on leads to its detachment in the heating zone, and heating less than 150 ° C makes it impossible to level the wall thickness due to surface tension forces due to the high viscosity of the glass. and free retraction of the workpiece under its own weight.

Pre landing

glass by pulling the workpiece under its own weight for a length of less than 2-3 times the wall thickness of the workpiece leads to overheating of the gauge and sticking of glass on it, causing destruction. Repeating the workpiece to a length greater than 2-3 wall thickness of the workpiece, leads to underheating of the caliber and rupture of the workpiece due to the resulting thermal shock when heat is taken from the glass.

Using the proposed method allows to improve the quality of calibrated polygonal shells,

eliminate their thickness variation, reduce material consumption due to the possibility of increasing the gap between the workpiece and the caliber, as well as reducing

sew the destruction of blanks in the process of their calibration.

The method improves the technology of obtaining high-precision polygonal shells, which leads to a reduction in the marriage by 15-20%.

The proposed method is simple to implement and does not require complicated control and process equipment.

Claims (1)

Invention Formula A method of calibrating glass tubular shells by placing 814 caliber inside the workpiece, its heating and subsequent precipitation of the softened glass mass to the caliber by evacuating the cavity between the inner wall of the workpiece and the outer wall of the caliber, characterized in that, in order to improve the calibration accuracy, the workpiece is heated to a temperature above temperature of onset of softening glass. 150–200 ° C, and after the preheat is heated, the filling is carried out by its own mass for a length equal to 2-3 wall thicknesses blanks. vanouum FI.1 - FIG. g cpuff.3 (rigging Editor N.Kishtulinets Compiled by L.Golubeva Tehred A. Kravchuk Order 2390/21 Circulation 427 Subscription VNIIPI USSR State Committee for inventions and discoveries. 113035, Moscow, Zh-35, Raushsk nab. 4/5 Production and printing company, Uzhgorod, st. Project, 4 Proofreader V. Booth ha