GB1585366A - Method for the connection of glass parts - Google Patents

Description

(54) METHOD FOR THE CONNECTION OF GLASS PARTS (71) We, CORNING GLASS WORKS, a corporation organised and existing under the laws of the State of New York, United States of America, of Corning, County of Steuben, State of New York, United States of America, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: In chemical engineering, there is frequently a need for glass elements, and in particular elements of special glass of the borate-silicate type, in the form of columns, hoods, reducers, balloons, tee and elbow pipes and other piping, etc., designed to be connected together by butt-joints.

These parts are submitted to stresses induced by the working conditions (temperature and pressure) to which they are exposed, such strains having the effect of imparting bending and bulging stresses, forming a convex shape under the most frequent conditions of high internal pressure, or forming a concave shape under conditions of reduced internal pressure.

As glass is relatively brittle, the field of utilization of glass elements is limited, when taking into consideration the impossibility of exceeding a safety limit for the tensile strength, so as to avoid the risk of rupture.

The present invention makes it possible to increase substantially the field of utilization, and in every case, to improve substantially the strength of the glass elements under the working conditions, which for this reason may be harder; in this connection, the invention should have applications particularly interesting for the manufacture of glass elements of large dimensions.

This invention provides a method for butt-joining two glass elements, each having a tubular body portion and an integral radially extending annular flange, which comprises clamping the flanges together using a clamping device which acts upon the flanges in such a manner that the forces applied by the clamping device act on the flanges in a different direction from the forces between the flanges thereby creating a torque which induces stresses in the tubular body, which stresses are of opposite sense to the stresses expected to be induced in the tubular body under conditions of use of apparatus incorporating the butt-jointed glass elements.

Preferably the direction of the forces acting on the flanges are determined by the position of a sealing ring between the flanges and/or of a packing between each flange and the clamping device.

Thus it is clear that, while remaining inside the boundaries of deformability of said element, it will be possible by introducing the maximum prestress, to have a deformation range substantially twice as large.

Evidently it will be of advantage, if it is desired that the element be exposed to nearly maximum stress conditions, to calculate and choose the prestress so that the deformation of the element, when unstressed is the same as that in the working condition, but of opposite sense.

If on the contrary it is desired to have in the working condition a low or nil deformation, it will be sufficient to impart to the element a prestress which will be merely balanced in the working condition.

The present invention will now be described in greater detail by way of example with reference to the drawings in which: Figure 1 is a partial half section view showing a conventional coupling of two collar flanges of glass elements; Figure 2 is a diagrammatic view showing in an overmagnified manner the deformation of such an element under working conditions; Figures 3 and 4 are schematic views similar to Figure 2 showing how the present invention is put in practice in the case of an element, when unstrained and under working conditions respectively; Figure 5 is a partial section view at a greater scale of one embodiment of the present invention in connection with a modified collar flange.

In Figure 1, there is to be seen the coupling of two glass tubes 1, the ends of which are formed with integral collar flanges 2, in engagement with one another, with interposition of a sealing gasket 3, and held together by means of couplings 4 tightened by bolts 5 and nuts 6. So as to avoid the troublesome direct contact of glass-metal, there is interposed a packing 7, for example made of a composition elastomer-asbestos, often a so-called "insert", as an intermediate engaging member between each coupling 4 and the adjacent collar 2. The arrows F1-F2 show the directions of the coupling strains transmitted by gasket 3 and packings 7 to the glass collars 2. It will be apparent that these forces are substantially coincident and do not create any twisting torque.

Internal pressure P (see Figure 2), in element 1 imparts a deformation which biases the tube wall towards an inflated shape, and causes the collar 2 to twist in the direction indicated by arrow f. This produces twisting stresses in the glass, which being a brittle material, cannot without breaking support undue stresses of this nature.

According to the present invention, and as is apparent in Figures 3 and 5, there is provided a disposition such that in unstrained conditions, i.e. at the time of joining the elements, the application points of forces F1 and F2, applied respectively by gasket 3 and packings 7, are not coincident, as previously, but are off-set so as to provide a twisting torque at the level of collars 2, biasing these to turn in the direction indicated by arrow f, and cause the wall of tube to bulge inwardly.

Thus, when tube 1 is in the working condition, with an inner pressure P (see Figure 4), the initial deformation of the rest position will be more or less resorbed, and the glass body will be submitted to low stress, which in every case is less than in the conventional case where there is no stress in the non-working condition of the elements.

It is to be noted that the above example relates to the working conditions of the tube with an inner overpressure P. If there were an external overpressure, the direction of the twisting torque F1-F2 would have to be reversed, and it would be sufficient for that, that the application point of F1 be shifted towards the axis of the tube with respect to the application point of F2.

Figure 5 is a view similar to that of Figure 1 with the same reference numerals used for like parts but illustrating how the gasket 3 and packings 7 should be arranged in accordance with the invention.

WHAT WE CLAIM IS: 1. A method for butt-joining two glass elements, each having a tubular body portion and an integral radially extending annular flange, which comprises clamping the flanges together using a clamping device which acts upon the flanges in such a manner that the forces applied by the clamping device act on the flanges in a different direction from the forces between the flanges thereby creating a torque which induces stresses in the tubular body, which stresses are of opposite sense to the stresses expected to be induced in the tubular body under conditions of use of apparatus incorporating the butt-jointed glass elements.

2. A method as claimed in claim 1 wherein the direction of the forces acting on the flanges are determined by the position of a sealing ring between the flanges and/or of a packing between each flange and the clamping device.

3. A method for butt-jointing two glass elements substantially as described herein with reference to and as shown in Figures 3 to 5 of the drawings.

4. An assembly of successive buttjointed glass elements each having a tubular body portion and at least one integral radially extending annular flange wherein the butt-joints are formed using a method as claimed in any one of claims 1 to 3.

5. An assembly as claimed in claim 4, wherein the butt-joints are formed by a method substantially as described herein with reference to and as shown in Figure 5 of the drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (5)

**WARNING** start of CLMS field may overlap end of DESC **. similar to Figure 2 showing how the present invention is put in practice in the case of an element, when unstrained and under working conditions respectively; Figure 5 is a partial section view at a greater scale of one embodiment of the present invention in connection with a modified collar flange. In Figure 1, there is to be seen the coupling of two glass tubes 1, the ends of which are formed with integral collar flanges 2, in engagement with one another, with interposition of a sealing gasket 3, and held together by means of couplings 4 tightened by bolts 5 and nuts 6. So as to avoid the troublesome direct contact of glass-metal, there is interposed a packing 7, for example made of a composition elastomer-asbestos, often a so-called "insert", as an intermediate engaging member between each coupling 4 and the adjacent collar 2. The arrows F1-F2 show the directions of the coupling strains transmitted by gasket 3 and packings 7 to the glass collars 2. It will be apparent that these forces are substantially coincident and do not create any twisting torque. Internal pressure P (see Figure 2), in element 1 imparts a deformation which biases the tube wall towards an inflated shape, and causes the collar 2 to twist in the direction indicated by arrow f. This produces twisting stresses in the glass, which being a brittle material, cannot without breaking support undue stresses of this nature. According to the present invention, and as is apparent in Figures 3 and 5, there is provided a disposition such that in unstrained conditions, i.e. at the time of joining the elements, the application points of forces F1 and F2, applied respectively by gasket 3 and packings 7, are not coincident, as previously, but are off-set so as to provide a twisting torque at the level of collars 2, biasing these to turn in the direction indicated by arrow f, and cause the wall of tube to bulge inwardly. Thus, when tube 1 is in the working condition, with an inner pressure P (see Figure 4), the initial deformation of the rest position will be more or less resorbed, and the glass body will be submitted to low stress, which in every case is less than in the conventional case where there is no stress in the non-working condition of the elements. It is to be noted that the above example relates to the working conditions of the tube with an inner overpressure P. If there were an external overpressure, the direction of the twisting torque F1-F2 would have to be reversed, and it would be sufficient for that, that the application point of F1 be shifted towards the axis of the tube with respect to the application point of F2. Figure 5 is a view similar to that of Figure 1 with the same reference numerals used for like parts but illustrating how the gasket 3 and packings 7 should be arranged in accordance with the invention. WHAT WE CLAIM IS:

1. A method for butt-joining two glass elements, each having a tubular body portion and an integral radially extending annular flange, which comprises clamping the flanges together using a clamping device which acts upon the flanges in such a manner that the forces applied by the clamping device act on the flanges in a different direction from the forces between the flanges thereby creating a torque which induces stresses in the tubular body, which stresses are of opposite sense to the stresses expected to be induced in the tubular body under conditions of use of apparatus incorporating the butt-jointed glass elements.

2. A method as claimed in claim 1 wherein the direction of the forces acting on the flanges are determined by the position of a sealing ring between the flanges and/or of a packing between each flange and the clamping device.

3. A method for butt-jointing two glass elements substantially as described herein with reference to and as shown in Figures 3 to 5 of the drawings.

4. An assembly of successive buttjointed glass elements each having a tubular body portion and at least one integral radially extending annular flange wherein the butt-joints are formed using a method as claimed in any one of claims 1 to 3.

5. An assembly as claimed in claim 4, wherein the butt-joints are formed by a method substantially as described herein with reference to and as shown in Figure 5 of the drawings.