Glass tube element with improved quality

Abstract

The invention relates to a glass tube element comprising at least one section in the form of a hollow cylinder, wherein the section has at least one shell which encloses at least one tube cavity; wherein at least one path which extends over the surface of the shell facing away from the tube cavity can be defined; wherein the path extends through at least one first region of the shell in which the stress values lie in a first interval and at least one second region of the shell in which the stress values lie in a second interval. The stress pattern over and / or under the surface is designed in such a way that the glass tube element with the different stress regions is particularly suitable for subsequent processing. This design scheme in particular indicates a particularly high quality of the glass tube element when the different regions are arranged symmetrically.

Description

TECHNICAL FIELD

[0001] The present invention relates to a glass tube element. BACKGROUND

[0002] Glass tube elements are widely used as basic components in many different industries. One reason for this is that glass tube elements have the advantage that they can be reshaped in many different ways at least partially in a subsequent processing chain. A wide variety of different products can be produced with only a few different glass tube elements as basic components. This enables a flexible and diverse product range to be offered at controllable costs and with widely available technical means.

[0003] In particular in the field of pharmaceutical containers, glass tube elements are of particular interest as basic components of vials, syringes, etc. Furthermore, glass can be produced such that it is free of toxic components such as Pb, As and Cd and has a high chemical stability and a high chemical inertness. Due to the high chemical stability of glass, a deposition or leakage of substances from the glass wall (or shell) of the glass tube element can be eliminated or at least reduced, which in particular indicates that glass tube elements are very suitable for the pharmaceutical sector.

[0004] In addition to the high degree of freedom in the choice of design, it is clear that glass tube elements have excellent properties for use as a basic component of a pharmaceutical container together with a pharmaceutical composition.

[0005] However, high demands are placed on pharmaceutical containers. And therefore also on glass tube elements. In order to meet the respective specifications, it is in particular required that the respective basic components have a uniform design, the geometric parameters of which are to be controlled within strict ranges. In this way, it can be ensured that the products manufactured on the basis of the glass tube elements, for example syringes, are not themselves under strain and do not mismatch with other components, for example caps, etc., to which they are to be connected later. This generally allows a safe interaction of the product with other components, as well as a safe handling of the product.

[0006] Otherwise, critical situations can arise during production or during use. A breakage of the product, for example a pharmaceutical container, can occur. As a result, the pharmaceutical composition held in the container can be lost, in addition, a danger can arise for the person handling the pharmaceutical container.

[0007] The quality requirements for pharmaceutical containers thus also apply to the basic components in the form of glass tube elements. To date, a wide variety of glass tube element geometries has been established, with which glass tube elements can be optimized to obtain a high-quality glass tube element.

[0008] However, since the quality requirements are constantly increasing, it is necessary to further improve the quality of the pharmaceutical containers and thus also of the glass tube elements. SUMMARY

[0009] It is therefore an object of the present application to provide a glass tube element of improved quality which is particularly suitable for use as a basic component for further processing such as reshaping in accordance with the requirements of the pharmaceutical industry. It is a further object of the present application to provide a use of such a glass tube element and a method for producing such a glass tube element.

[0010] The problem is solved according to a first aspect of the present application in that the glass tube element comprises:

[0011] at least one section in the form of a hollow cylinder, wherein the section has at least one shell which encloses at least one tube cavity;

[0012] wherein at least one path extending on a surface of the shell facing away from the tube cavity can be defined;

[0013] wherein the path extends through at least one first region of the shell in which the stress value lies within a first interval and at least one second region of the shell in which the stress value lies within a second interval.

[0014] Accordingly, the present application is based on the surprising finding that the quality of the glass tube element is improved, and thus, if the stress pattern on and / or below the surface is designed such that there are different stress regions, the glass tube element is particularly suitable for subsequent processing, for example at least partial reshaping. It has been found that this design scheme in particular proves the glass tube element to have a particularly high quality when the different regions are arranged symmetrically.

[0015] The inventors have found that in order to improve the symmetry of the distribution of the first and second regions, the strength of the glass product is increased. Surprisingly, the improved symmetry in turn improves the quality of the glass tube element. As a result, the inventors have found that the improvement in quality is accompanied by an improvement in the geometric parameters, for example the straightness of the glass tube element. It is immediately apparent that the improvement in straightness enables an improved usability for subsequent manufacturing steps, and an improved usability of the glass tube element in combination with other elements. This is because, for example, the mutual couplability is improved. The improved stress pattern also allows the glass tube element to be divided into sub-elements in a more reliable and safe manner.

[0016] The inventive concept allows a high-quality glass tube element to be obtained in a surprising, reliable and inexpensive manner, thereby obtaining a high-quality product based on such a glass tube element.

[0017] In a preferred embodiment, the stress is a mechanical stress. It is acknowledged that the terms "shell" and "wall" of the (cylinder / glass tube element) are used synonymously here.

[0018] It is acknowledged that the terms "outer surface" and "surface of the shell facing away from the tube cavity" are used synonymously here.

[0019] It is generally accepted that preferably each "stress value" herein refers to a difference value Δσ between an axial stress value σ 轴向 and a radial stress value σ 径向 Thus, axial and radial are defined with respect to the central axis of the glass tube element.

[0020] In practice, the radial stress value is usually small relative to the axial stress value, so that it can be neglected from a practical point of view. Moreover, the axial stress is usually the relevant stress for evaluating the quality of the glass tube element, e.g. with respect to the breaking strength.

[0021] It is generally accepted that the person skilled in the art knows how to measure stress values of different surface regions. For example, measuring a stress value of a surface region can comprise an optical measurement. In this regard, each surface region is successively scanned or rasterized at different points by means of a light ray (e.g. a laser beam) tangential to the respective surface point and the optical retardation of the light ray is measured. Each optical retardation can in turn be converted into a stress value, e.g. by means of the Wertheim Law.

[0022] It is known to the person skilled in the art that the optical retardation values can be converted into corresponding mechanical stress values. In particular, this can be done using the "Wertheim Law", i.e. wherein is the optical retardation, C is the stress optical constant, Δσ is the stress difference between the stress along the central axis of the glass tube element (i.e. axial) and the stress perpendicular to the central axis of the glass tube element (i.e. radial), and d is the thickness of the sample through which the light ray passes during the optical measurement.

[0023] This means that the stress optical constant is defined as a material property of the respective glass material. The stress optical constant can be determined by measuring the optical retardation of a sample having defined stress parameters.

[0024] Preferably, the stress optical constant has a value between 2.2 TPa -1 and 4 TPa -1 .

[0025] In a preferred embodiment, alternatively or additionally, the stress optical constant can be measured according to Procedure C (Glass Disc Method) described in ASTM Standard C770-16 entitled "Standard Test Method for Measuring Glass Stress-Optical Coefficient", the content of which is incorporated herein by reference in its entirety.

[0026] Thus, by scanning / rasterizing the surface region of interest at a number of points and subsequently applying the Wertheim Law, the stress value of this surface region can be obtained.

[0027] For example, for the optical measurement, the light has a linear polarization which encloses an angle of 45 degrees with the central axis of the glass tube element. For example, the light has a light wavelength of 630 nm, 633 nm or 635 nm. For example, the ambient temperature is room temperature.

[0028] The following description of the optical measurement is made in more detail, reference being made to the corresponding parts of the present application in order to avoid unnecessary repetition. Figure 1 The following description of the optical measurement is made in more detail, reference being made to the corresponding parts of the present application in order to avoid unnecessary repetition.

[0029] In one embodiment, alternatively or additionally, it is preferred that the path preferably follows at least one intersection line over the entire length or a section of the glass tube element, which intersection line can be obtained by the intersection of a plane comprising the entire central axis of the glass tube element with the surface of the housing facing away from the tube cavity.

[0030] If the path extends parallel to the central axis of the glass tube element, it is possible to define an arrangement of the different regions in the longitudinal direction, which can be particularly useful in the case of a stress pattern change predominantly or especially in this direction.

[0031] In one embodiment, alternatively or additionally, it is preferred that the path preferably follows at least one intersection line over the entire circumference or at least one section of the glass tube element, which intersection line can be obtained by the intersection of a plane perpendicular to the central axis of the glass tube element with the surface of the housing facing away from the tube cavity.

[0032] If the path extends perpendicular to the central axis of the glass tube element, it is possible to define an arrangement of the different regions in the circumferential direction, which can be particularly useful in the case of a stress pattern change predominantly or especially in this direction.

[0033] In one embodiment, alternatively or additionally, it is preferred that, in at least one direction along the path, the second region follows the first region.

[0034] If the first region and the second region are arranged in succession, it is particularly possible to obtain a uniform optical retardation. Further, such a stress pattern can be realized in a particularly efficient and inexpensive manner.

[0035] In one embodiment, alternatively or additionally, it is preferred that the path extends through a first number of first regions and a second number of second regions, wherein preferably the first regions and the second regions are repeatedly alternating, preferably directly consecutive, in at least one direction along the path, and wherein preferably the first number comprises the same number of regions as the second number.

[0036] If the stress pattern of the glass tube element comprises more than one first region and more than one second region, a highly regular stress pattern can be achieved and thus a uniform distribution of the optical retardation can be achieved. This in turn has a positive effect on the quality of the actual glass tube element.

[0037] If the different types of regions are arranged directly consecutive (along the defined path), i.e. a first second region directly follows a first first region, a second first region directly follows the first second region, a second second region directly follows the second first region, and so on, a specific regular pattern can be achieved. This has proven to be very useful for obtaining a high quality glass tube element.

[0038] If the same number of first regions and second regions is used, the regularity can even be further improved.

[0039] In preferred embodiments, the number of first regions is 2, 3, 5, 10, 15, 20, 25, 30 or 50. In preferred embodiments, the number of second regions is 2, 3, 5, 10, 15, 20, 25, 30 or 50. In preferred embodiments, the number of first regions and the number of second regions are both 2, 3, 5, 10, 15, 20, 25, 30 or 50.

[0040] In one embodiment, alternatively or additionally, it is preferred that, in at least one direction along the path, the path extends through at least one first region and at least one third region of the shell, at which third region the stress value lies within a third interval, wherein preferably, in this direction along the path, the third region (1) directly follows the first region and / or (2) is arranged, preferably directly arranged, between the first region and the next first or second region downstream of the path.

[0041] It has proven particularly useful to include a third region having a stress value which is at least partially different from the stress values of the first and second regions. Surprisingly, it has turned out that, despite the third region breaking the preferred regular pattern of the first, second and / or third regions, it still leads to an improved quality.

[0042] If the third region is "sandwiched" (i.e. consecutive along the defined path) between a first region and a second region or between two first regions, a specific high quality glass tube element is obtained. Of course, it is preferred that these regions are directly consecutive.

[0043] In an embodiment, alternatively or additionally, it is preferred that, in at least one direction along the path, within at least one second region, preferably within all second regions, the path extends through a plurality of consecutive sub-regions of the second region, where the stress value of each sub-region lies within the respective sub-interval comprised by the second interval,

[0044] wherein preferably the value range of each sub-interval is at least partially different, at least partially the same, at least partially overlapping and / or at least partially non-overlapping.

[0045] If the second region is divided into a plurality of sub-regions, the stress pattern can be controlled on a more subtle basis. This is particularly useful for obtaining high quality glass tube elements, for which it has proven to be beneficial to perform a high depth control of the stress pattern.

[0046] In a preferred embodiment, the at least one or each second region has 2, 3, 4, 5 or more than 5 sub-regions.

[0047] In an embodiment, alternatively or additionally, it is preferred that the different regions are arranged along the path such that at least one of the second regions and / or third regions is arranged diametrically opposite to at least one of the first regions, preferably each of the first regions; and / or wherein preferably the value range of the first interval is different and / or non-overlapping from the value range of the second interval.

[0048] Since in a preferred embodiment high value regions and low value regions can be arranged alternatingly, the intervals of the regions are typically non-overlapping.

[0049] In an embodiment, alternatively or additionally, it is preferred that the value of the first interval corresponds to a compressive stress, the upper boundary of the second interval has an absolute value greater than the maximum absolute value of the first interval, and / or wherein the first interval comprises a value range between -0.5 MPa and -10 MPa, preferably between -1 MPa and -8 MPa, more preferably between -1 MPa and -5 MPa, -4 MPa and -6 MPa and / or -3 MPa and -8 MPa, and / or the second interval corresponds to an offset of up to -5 MPa relative to the first interval, preferably between -0.5 MPa and -3 MPa, more preferably between -1 MPa and -2.5 MPa.

[0050] In a preferred embodiment, the first and second intervals are consecutive. This allows to provide a particularly useful design specification.

[0051] For example, the first interval can comprise a range of values between -0.5 MPa and -10 MPa, and the second interval corresponds to an offset of up to -3 MPa relative to the first interval. Preferably, this means that if the first interval is between -0.5 MPa and -10 MPa, the second interval is between -10 MPa and -13 MPa.

[0052] In one embodiment, alternatively or additionally, it is preferred that the first interval can comprise a range of values between -0.5 MPa and -2 MPa, -0.5 MPa and -3 MPa, -0.5 MPa and -4 MPa, -0.5 MPa and -5 MPa, and / or -0.5 MPa and -6 MPa.

[0053] In one embodiment, alternatively or additionally, it is preferred that the second interval can correspond to an offset of up to -1 MPa, -1.5 MPa, -2 MPa and / or -2.5 MPa relative to the first interval.

[0054] In one embodiment, alternatively or additionally, it is preferred that the segments of the path that lie within the first region and / or the second region, in particular within the sub-regions of the second region, all have the same length.

[0055] If the segments of the path that lie within the first region all have the same length, the stress pattern can be realized in a particularly regular, and thus preferred, manner with regard to the quality of the glass tube element. This is the case because, in this case, the individual first regions have the same length in the direction of the path, for example axial or circumferential.

[0056] If the segments of the path that lie within the second region all have the same length, the stress pattern can be realized in a particularly regular, and thus preferred, manner with regard to the quality of the glass tube element. This is the case because, in this case, the individual second regions have the same length in the direction of the path, for example axial or circumferential.

[0057] If the segments of the path that lie within the first region and the second region respectively have the same length, the stress pattern can be realized in a particularly regular, and thus preferred, manner with regard to the quality of the glass tube element. This is the case because, in this case, all first regions and second regions have the same length in the direction of the path, for example axial or circumferential.

[0058] In one embodiment, alternatively or additionally, it is preferred that the segments of the path that lie within the sub-regions of at least one second region, in particular of all second regions, have a length that is particularly defined for all sub-regions, the sub-regions having a respective sub-range.

[0059] If the length of the path is the same in each sub-area having the same range of values, regularity can be improved, the uniformity of the optical delay can be improved, and thus the quality of the glass tube element can be improved. This further improves the uniformity, considering only the sub-areas of one second area or even all second areas.

[0060] For example, all second areas have a first sub-area, a second sub-area and a third sub-area. The first and third sub-areas have the same range of values which is different from the range of values of the second sub-area. In this case, it is preferred that the path has the same length in all first sub-areas and in all second sub-areas, i.e. in all second areas. In the second sub-area, the path can have different lengths. However, it is not excluded that for the second sub-area the same length as for the first and third sub-areas is defined.

[0061] In one embodiment, alternatively or additionally, it is preferred that the first area, the second area, preferably the sub-areas and / or the third area each comprise (i) at least one surface area of the shell which is facing away from the lumen and / or (ii) at least one volume area of the shell, wherein preferably the thickness of the shell is measured in a perpendicular direction from the surface of the shell which is facing away from the lumen towards the lumen.

[0062] It is acknowledged that the first area and the second area can be a surface area (i.e. a two-dimensional area) or a volume area (i.e. a three-dimensional area), as outlined in more detail elsewhere. In the latter case, it is preferred that in the respective first and / or second area the thickness is the same everywhere.

[0063] It is acknowledged that in any case the first area and the second area comprise at least a portion of the outer surface of the shell, and thus of the glass tube element. This is because the thickness of a volume area is measured from the outer surface of the shell. The outer surface of the shell is synonymous with the surface of the shell which is facing away from the lumen.

[0064] In one embodiment, alternatively or additionally, it is preferred that the first area of the shell comprises at least one first surface area of the shell. In one embodiment, alternatively or additionally, it is preferred that the second area of the shell comprises at least one second surface area of the shell.

[0065] In one embodiment, alternatively or additionally, it is preferred that, in particular for a plurality of parallelly extending paths of the defined kind,

[0066] It is possible to define a first plurality of first areas, wherein the first areas of each first plurality are connected to each other by means of connected first super-areas of the shell,

[0067] a second group of second regions can be defined, wherein each second region of the second group is connected to each other second region of the second group by means of a connected second characteristic region of the shell,

[0068] In particular, a subgroup of subregions of second regions can be defined, wherein each subgroup of subregions is connected to each other subgroup of subregions by means of a connected characteristic subregion of the shell,

[0069] and / or

[0070] a third group of third regions can be defined, wherein each third region of the third group is connected to each other third region of the third group by means of a connected third characteristic region of the shell,

[0071] wherein preferably the stress values within the first characteristic regions lie within the first interval, the stress values within the second characteristic regions lie within the second interval, in particular the stress values within the characteristic subregions lie within the subintervals corresponding to the respective subregions, and / or the stress values within the third characteristic regions lie within the third interval.

[0072] It has surprisingly been found that, although from the perspective of a single path it would be sufficient that the first regions, the second regions and the third regions each only occur (and possibly in the vicinity of) locally at the path, this has apparently not been necessary and conventional so far.

[0073] In fact, the one or more first characteristic regions, the one or more second characteristic regions and / or the one or more third characteristic regions can each be large regions, each covering a large portion of the shell. In fact, there can be more than two first characteristic regions and / or more than two second characteristic regions and / or more than two third characteristic regions.

[0074] For example, there can be more than two characteristic regions. The more than two first characteristic regions can be identical in terms of design, stress values, etc. However, they can still be separated from each other. This is possible because the respective first regions are grouped in such a way that they are each connected by a respective first characteristic region, which actually exists in the shell, in particular in the outer surface of the shell. Preferably, in the first characteristic regions the stress values lie within the first interval, and outside the first characteristic regions there can be other stress values. This criterion is essential for the first regions to be properly grouped.

[0075] In other words, if two independent first regions cannot be connected by a common characteristic region, they cannot be grouped in the same group. This can be the case if the common characteristic region would have to span a region of the shell, in which the stress values lie outside the respective interval corresponding to the characteristic region. The same applies to the second characteristic regions and the third characteristic regions.

[0076] It is generally accepted that the definition of all parallelly extending paths is identical and that all aspects defined for one path apply accordingly to the other paths.

[0077] In one embodiment, alternatively or additionally, it is preferred that the first special region, the second special region, in particular the special sub-region and / or the third special region, on the expanded cylindrical shell, preferably the respective outer surface, i.e. the aforementioned surface facing away from the lumen, is designed in the form of at least one strip, preferably in the form of a plurality of parallel and / or non-parallel strips, respectively.

[0078] The special regions can be designed in the form of strips, which can effectively provide them on the glass tube element.

[0079] In one embodiment, alternatively or additionally, it is preferred that the number of first special regions, the number of second special regions, in particular the number of special sub-regions and / or the number of third special regions of the shell is between 1 and 100, preferably between 2 and 50, more preferably between 2 and 30, most preferably between 5 and 20.

[0080] The more special regions are used, the more intensive the stress pattern can be effectively applied to the glass tube element. This is true because due to the curvature of the surface of the glass tube element, it can be more convenient to apply a plurality of smaller strips to provide a high coverage of the stress pattern than to apply only one single wide strip.

[0081] In one embodiment, alternatively or additionally, it is preferred that when the glass tube element is optically measured by means of at least one light ray extending along a measurement path, which extends along a measurement direction perpendicular to the main extension direction of the glass tube element, which is tangential to the surface of the shell facing away from the lumen and which contacts this surface for different measurements at different positions, each having a different azimuth angle in a cylindrical coordinate system fixed to the glass tube element and with the origin of the cylindrical coordinate system on the central axis of the glass tube element, the optical retardation values of the light rays obtained by the different measurements fall within a range between 3 nm and 30 nm, wherein preferably

[0082] (1) the wavelength of the light rays is between 250 nm and 900 nm, preferably between 390 nm and 800 nm, most preferably 394 nm or 633 nm;

[0083] (2) the glass tube element is surrounded by at least one fluid such that at least the surface of the shell facing away from the lumen is in contact with the fluid;

[0084] (3) the glass tube element is completely immersed in at least one fluid such that both the surface of the shell facing away from the lumen and the surface of the shell facing towards the lumen are in contact with the fluid;

[0085] (4) Preferably, the optical density of the fluid differs at most 1% from the optical density of the glass material of the glass tube element for the wavelength of the light rays;

[0086] (5) Preferably, the optical density of the fluid is between 1.2 and 2.5, preferably between 1.3 and 1.7, most preferably 1.362, 1.460, 1.463, 1.472, 1.473, 1.474, 1.486, between 1.492 and 1.493, 1.497, 1.501, 1.516, 1.525 or between 1.43 and 1.61 for the wavelength of the light rays;

[0087] (6) Preferably, the fluid comprises ethanol, olive oil, carbon tetrachloride, sunflower oil, turpentine, glycerol, furfuryl alcohol, dibutyl phthalate 84-74-2, toluene, benzene, dimethyl phthalate, monochlorobenzene or silicone oil or any combination thereof;

[0088] (7) The optical retardation values of the light rays obtained by the different measurements all fall between 10 nm and 150 nm, preferably between 20 nm and 100 nm, and / or the optical retardation values of the light rays obtained by the different measurements all fall between 3 nm and 30 nm, preferably between 4 nm and 25 nm, more preferably between 5 nm and 20 nm;

[0089] (8) The different azimuth angles are chosen from the integer values between 0 and 359 degrees, including 0 and 359 degrees, for 360 measurements;

[0090] (9) The different regions are arranged along the path such that the optical retardation values lie within this magnitude of the range;

[0091] and / or

[0092] (10) The measurements are performed for positions having the same height and / or the same radius in the cylindrical coordinate system.

[0093] The surprising finding is that a certain preferred arrangement of the different stress regions is obtained if the optical retardation is uniform, thereby obtaining a certain robust and preferred glass tube element.

[0094] The inventors found that the optical retardation is uniform if the variation is limited within a certain range. The surprising finding is that the lower boundary of the range is larger than zero and the upper boundary is about ten times the lower boundary.

[0095] The measurements can be performed more stably if the glass tube element is completely immersed in water.

[0096] More reliable measurement results can be obtained if a suitable fluid is chosen, in particular a fluid whose optical density is close to the optical density of the glass material of the glass tube for the wavelength used for the measurements.

[0097] It is known that preferably all the specific values fall into a range having a size between X and Y if the difference between each two specific values is between X and Y (and including X and Y). In other words, a common offset of the measured optical retardation values is not important here.

[0098] However, in one embodiment, alternatively or additionally, the measured optical retardation can have a value between 10 nm and 150 nm for a housing having a thickness of 1 mm and for a sample thickness of 1 mm through which the light rays pass during the optical measurement.

[0099] It is acknowledged that even if the measurement path is tangential to the surface of the housing which faces away from the lumen, the person skilled in the art understands that in the actual optical measurement one or more light rays are always included which are offset towards the central axis of the glass tube element and / or have a certain spatial extension in a direction perpendicular to the propagation direction, i.e. they propagate at least partially within the housing. For example, preferably the tangential light rays are at most 10 pm below the outer surface.

[0100] By arranging these regions in the suggested manner, the variation of the optical retardation can be precisely defined.

[0101] Since in the preferred embodiment the high-value regions and the low-value regions can be arranged in an alternating manner, the intervals of the regions are generally non-overlapping.

[0102] The person skilled in the art knows that the value of the optical retardation can be converted into a value of the corresponding mechanical stress. In particular, this can be done using the "Vitreous Law", i.e. wherein is the optical retardation, C is the stress optical constant, AS is the stress difference between the stress along the central axis of the glass tube element (i.e. axial) and the stress perpendicular to the central axis of the glass tube element (i.e. radial), and d is the thickness of the sample through which the light rays pass during the optical measurement.

[0103] This means that the stress optical constant is defined as a material property of the corresponding glass material. The stress optical constant can be determined by measuring the optical retardation of a sample having defined stress parameters.

[0104] Preferably, the stress optical constant has a value between 2.2 TPa -1 and 4 TPa -1 .

[0105] In one embodiment, alternatively or additionally, it is preferred that the glass tube element has a length between 0.5 m and 5 m, preferably between 0.7 m and 3 m, more preferably between 1 m and 2 m, even more preferably between 1.2 m and 1.8 m, most preferably 1.5 m.

[0106] Glass tube elements having a length in the preferred range have a higher quality. This is because a more stable, more defined glass tube element is obtained.

[0107] In an embodiment, alternatively or additionally, it is preferred that the maximum outer diameter is between 1 mm and 100 mm, preferably between 3 mm and 60 mm, more preferably between 6 mm and 45 mm, 8 mm and 19 mm, 6 mm and 50 mm or 8 mm and 30 mm.

[0108] Glass tube elements having a maximum outer diameter in the preferred range have a higher quality. This is because a more stable, more defined glass tube element is obtained.

[0109] In an embodiment, alternatively or additionally, it is preferred that the shell has an average thickness between 0.1 mm and 5 mm, preferably between 0.2 mm and 3 mm, more preferably between 0.3 mm and 2.5 mm, most preferably between 0.4 mm and 1.8 mm.

[0110] Glass tube elements having a preferred shell average thickness are particularly suitable for applying the method of the present application, because for such glass tube elements more reliable first and second ratios can be obtained.

[0111] The term "average thickness" herein refers to the average thickness of the shell over the length of the glass tube element. If the thickness of the shell has a constant value everywhere, the average thickness is the same as the actual thickness.

[0112] In an embodiment, alternatively or additionally, it is preferred that the glass tube element comprises at least partly a silicate glass, such as a soda-lime glass and / or an alumino-silicate glass and / or a borosilicate glass.

[0113] In an embodiment, alternatively or additionally, it is preferred that the glass tube element, in particular the glass material thereof, has a transition temperature higher than 300 °C, preferably higher than 500 °C, more preferably higher than 520 °C, even more preferably higher than 530 °C, even more preferably higher than 550 °C, most preferably higher than 600 °C and / or lower than 900 °C, preferably lower than 800 °C, more preferably lower than 700 °C, even more preferably lower than 650 °C, most preferably lower than 630 °C.

[0114] Preferably, the transition temperature refers to the transition temperature of the glass used for the wall of the glass tube element.

[0115] In one embodiment, alternatively or additionally, it is preferred that the glass tube element is, preferably at least temporarily, connected, preferably integrally connected, to one or more other glass tube elements during its production and / or is part of at least one glass tube line.

[0116] It is more economic to produce one longer, even endless, glass tube line and then to finish individual glass tube elements in succession from this line in the desired length.

[0117] In one embodiment, alternatively or additionally, it is preferred that the average linear coefficient of thermal expansion (CTE) of the glass tube element, measured in the range from 20 °C to 300 °C, is between 3.0 and 10.0 x 10 -6 K -1 , preferably between 3.3 and 7.5 x 10 - 6 K -1 , more preferably between 4.7 and 6.0 x 10 -6 K -1 .

[0118] It is beneficial for glass tubes to have a lower CTE, which makes the product more uniform. Therefore, in preferred embodiments, the CTE is limited to not more than 6.9 x 10 -6 K -1 or not more than 5.9 x 10 -6 K -1 . The CTE can be measured according to DIN ISO 7991 :1987.

[0119] In one embodiment, alternatively or additionally, it is preferred that the glass tube element, preferably at least during a part of its production, at least during its cooling, is passed along a defined movement path with a defined movement speed through at least one cooling device in order to set a locally changed cooling rate of the glass tube element. Preferably, the movement path extends parallel to the main extension direction of the glass tube element and / or extends in horizontal direction.

[0120] Surprisingly, it has been found that the geometrical parameters of the glass tube element and thus the first, second and overall quality of the glass tube element can be improved if the glass tube element is subjected to a special treatment during its cooling. It has turned out that a locally changed cooling rate of the glass tube element can have a beneficial influence on the cooling process.

[0121] Preferably, the cooling rate is changed at the outer surface of the glass tube element. However, it is also possible to change the cooling rate elsewhere, for example within the shell of the glass tube element.

[0122] If the movement speed and the movement path are determined, the cooling process can be better controlled. In particular, it has been found that a straight or at least close to straight movement path is more suitable for a uniform and reproducible interaction.

[0123] The inventors believe that by using the above described process during cooling, using the cooling device and other settings respectively, the structure of the glass tube element, in particular the structure on, under and / or near the outer surface of the glass tube element, is controlled, thereby improving the geometrical properties of the glass tube element.

[0124] In one embodiment, alternatively or additionally, it is preferred that the movement speed is between 1 cm / s and 1000 cm / s, preferably between 20 cm / s and 800 cm / s, more preferably between 30 cm / s and 500 cm / s, most preferably 100 cm / s.

[0125] For the preferred speeds, an optimal interaction time between the cooling device and the glass tube element is obtained. Thus, also a higher quality glass tube element can be obtained.

[0126] In one embodiment, alternatively or additionally, it is preferred that the surface temperature of the glass tube element is temporarily between Tg- 50 °C and Tg+ 150 °C when the glass tube element passes through and / or along the cooling device.

[0127] The inventors found that a particularly beneficial interaction between the cooling device and the glass tube element can occur when the surface temperature of the glass tube element, in particular the temperature of the outer surface of the shell, is within a certain interval around the transition temperature of the material of the glass tube element, i.e. the glass. As a result, the quality of the glass tube element is improved.

[0128] The inventors believe that for the temperature range around the transition temperature, the performance of the glass tube element is improved due to the fact that the cooling device can be said to "imprint" a change compared to other temperatures, and thus the glass tube element can be advantageously influenced by the inventive concept.

[0129] In a preferred embodiment, the surface temperature is the temperature at the outer surface.

[0130] It is acknowledged that the surface temperature of the glass tube element is temporarily within the preferred temperature interval when the glass tube element passes through and / or along the cooling device. In other words, in a preferred embodiment, it is required that the surface temperature of the glass tube element is within the preferred temperature interval for a certain time when the glass tube element passes through and / or along the cooling device.

[0131] This does not exclude that the surface temperature is above the upper limit at the beginning of the passing / along and / or that the surface temperature is below the lower limit at the end of the passing / along.

[0132] In one embodiment, alternatively or additionally, it is preferred that the cooling device has at least one contact device, wherein the contact device at least from time to time and / or regionally contacts, preferably directly contacts, at least one region of the outer surface of the glass tube element.

[0133] It has surprisingly been found that the provision of a contact device allows to control the locally present cooling rate on the surface, in particular the outer surface, of the glass tube element in a precise, reliable and comfortable manner. It is also possible to control the moment at which the contact device contacts the glass tube element. This can be controlled, for example, by means of the respective spatial arrangement of the contact device within the cooling device, so that the glass tube element passes along the respective contact device at an earlier or later moment. Of course, it is preferred that not the entire contact device has to be in contact with the glass tube element, but this is also possible. It can be sufficient if only a part thereof is in contact with the glass tube element. Of course, it is also possible that not the entire outer surface of the glass tube element has to be in contact with the contact device, but it can also be sufficient if only a region of the outer surface of the glass tube element is in contact with the contact device.

[0134] These design parameters allow to effectively control the degree of interaction between the contact device and the glass tube element. The earlier the contact between the contact device and the glass tube element, the longer the contact time, the broader the contact range, the more interaction between the two can take place, and thus the more cooling can take place.

[0135] In a further preferred embodiment, alternatively or additionally, the cooling device has at least one fluid distributor device, which is designed to provide, preferably at least from time to time and / or regionally, a fluid, for example water, mist and / or air, preferably compressed air, on at least one region of the outer surface of the glass tube element.

[0136] The use of a fluid can improve the control of the cooling process of the glass tube element. In this way, in particular, a drastic change in temperature can be achieved in a short time. This can also be used to assist the cooling process carried out by the contact device.

[0137] Preferably, the fluid distributor is at least partially designed in the form of at least one annular nozzle. This allows a uniform (and circular) interaction between the fluid and the glass tube element to be achieved. In other words, using an annular nozzle can cover the entire outer surface of the glass tube element. It has proven to be at least sectionally advantageous for the straightness of the glass tube element.

[0138] In a preferred embodiment, the fluid distributor is used as part of at least one air bearing and / or in combination with at least one contact device. This makes it possible to achieve an interaction between the glass tube element and the contact device with reduced or even no direct contact between the two. This can reduce the contamination effect.

[0139] In an embodiment, alternatively or additionally, it is preferred that the cooling device has a plurality of contact devices, wherein preferably a first number of the plurality of contact devices successively and / or at different regions of the outer surface contact the outer surface of the glass tube element one after the other and / or a second number of the plurality of contact devices simultaneously and / or at different regions of the outer surface contact the outer surface of the glass tube element.

[0140] The use of more than one contact device can allow for a more efficient interaction between the cooling device and the glass tube element, thereby further improving the properties of the glass tube element.

[0141] If some or all of the contact devices successively (in space and / or in time) contact the outer surface of the glass tube element (wherein the contact devices do not necessarily contact the same region of the outer surface of the glass tube element, but at least some or all of the contact devices can contact different regions of the outer surface of the glass tube element), a gradient interaction can be obtained due to, for example, the contact occurring at different temperatures of the outer surface and / or with different interaction devices.

[0142] If some or all of the contact devices (for example, distributed in space) contact the outer surface of the glass tube element at the same time (but, for example, at different regions thereof), the interaction between the contact devices and the glass tube element can occur within a small physical space, and, thus, the size of the cooling device can be reduced only. This is beneficial from an economic point of view.

[0143] In an embodiment, alternatively or additionally, it is preferred that the center distance of each two of the two contact devices, preferably of the plurality of contact devices, arranged successively along the movement path, preferably the center distance measured along the movement path, is not more than 50 cm, more preferably not more than 40 cm, even more preferably not more than 30 cm, even more preferably not more than 20 cm, most preferably not more than 10 cm.

[0144] It has proven to be advantageous to allow for different distances between adjacent contact devices along the movement path. In addition, the distance between adjacent contact devices can vary. Preferably, the distance decreases. This can result in an increased number of subsequent interactions at higher surface temperatures, which can have a greater influence on the properties of the glass tube element than interactions at lower surface temperatures. This also allows for an interaction with the glass tube element within a shorter time.

[0145] It has proven to be advantageous that the increase in interactions is beneficial, even if it entails a higher setup cost. The resulting glass tube element has improved geometrical parameters, in particular improved first and second ratios, and thus an improved quality.

[0146] In a preferred embodiment, the center distance between adjacent contact devices is small or even very small, in particular compared to the length of the glass tube element.

[0147] In a preferred embodiment, the center distance between adjacent contact devices is small or even very small, in addition, the glass tube element is rotated while passing through the cooling device, in particular the contact device. It has proven that the straightness can be improved if a number of contact devices are in contact with the glass tube element within the cooling device. In particular, an improved straightness can be observed if the glass tube element (or its outer surface) has a temperature of about Tg when in contact.

[0148] In one embodiment, alternatively or additionally, it is preferred that at least one of the contact devices, more than one of the contact devices or all of the contact devices are / is in contact (preferably simultaneously) with two, three, four or more regions of the outer surface of the glass tube element via the respective contact region of the contact device, wherein preferably the contact regions and / or the regions of the outer surface contacted by each contact device are / is separated from one another.

[0149] If the contact device is designed such that a plurality of portions of the contact device interact, in particular contact, with the glass tube element, in particular at the outer surface, an improved, more efficient, more comprehensive and faster cooling process control can be achieved.

[0150] In one embodiment, alternatively or additionally, it is preferred that at least a third number of a plurality of contact devices, preferably two, three, four or five contact devices, form a contact device group. Wherein the contact devices of the contact device group are arranged around the glass tube element, preferably in a rotationally symmetrical manner. Preferably, at least a portion or all of the third number of contact devices are / is in contact with the glass tube element simultaneously at different regions of the outer surface of the glass tube element and / or from different spatial directions.

[0151] By means of a suitable spatial arrangement of the contact devices, the operation of the cooling process can be carried out quickly and reliably. This is the case because two or even more contact devices can be in contact with the glass tube element simultaneously and / or from different spatial directions. It has proven that a favorable influence on the properties of the glass tube element is achieved if the respective arrangement is employed.

[0152] In one embodiment, alternatively or additionally, it is preferred that the surface temperature of the glass tube element, after passing and / or along the path, can be brought to Tg- 200°C or less in the cooling device, in particular the contact device. And / or wherein at least one or all contact devices have a thermal conductivity of 1 W / (m x K) to 100 W / (m x K), preferably 10 W / (m x K) to 70 W / (m x K), most preferably 30 W / (m x K) to 50 W / (m x K), at least in the area of contact with the glass tube element, in particular in the area of the contact region.

[0153] By employing a design of the contact device with a specific thermal conductivity, the cooling process can be precisely controlled, so that the quality of the glass tube element can be improved.

[0154] In one embodiment, alternatively or additionally, it is preferred that at least one or all contact devices are designed as at least one caster, wherein preferably the glass tube element is movable, supportable, moved and / or supported along the movement path by the caster.

[0155] The use of a caster has a great degree of design freedom and flexibility. For example, different sizes, in particular different diameters, different materials, different thermal conductivities and different contact areas can be easily realized.

[0156] For example, the caster has at least one V-shaped recess at least partially in at least one cross-sectional plane, preferably in a plane comprising the central axis of the caster.

[0157] The recess allows two contact regions between the caster and the glass tube element to be realized at the same time. In other words, since the glass tube element can be supported by the caster within the space provided by the "V", the caster provides two side walls that can come into contact with the glass tube element.

[0158] The caster can also be used as a means of transport for moving the glass tube element at the same time. This is very economical.

[0159] It is recognized that one or more casters can also be replaced by a corresponding number of rollers.

[0160] In one embodiment, alternatively or additionally, it is preferred that at least one contact device, in particular one or more casters, is temperature-regulated, in particular cooled.

[0161] This allows the temperature difference between the contact device and the glass material to be precisely controlled.

[0162] In one embodiment, alternatively or additionally, it is preferred that each caster has at least one contact area contacting the glass tube element, which has at least one point with a distance of 10 cm or less, 5 cm or less, 3 cm or less, 1 cm or less, or 0.5 cm or less, respectively, to the central axis of the caster.

[0163] It has proven advantageous that the contact area of the caster is close to the central axis of the caster. This allows the dimensions of the caster to be limited by an upper limit, which in turn allows a compact arrangement and, in addition, results in an optimal interaction.

[0164] In one embodiment, alternatively or additionally, it is preferred that each caster has an outer diameter of 50 cm or less, preferably 30 cm or less, more preferably 15 cm or less, even more preferably 10 cm or less, even more preferably 5 cm or less, even more preferably 3 cm or less, and most preferably 1 cm or less.

[0165] It has proven advantageous that the dimensions of the caster are limited by an upper limit, which in turn allows a compact arrangement and, in addition, results in an optimal interaction. The smaller the individual casters, the more casters can be used in a small space and more casters can be arranged one behind the other. This allows a high interaction.

[0166] In one embodiment, alternatively or additionally, it is preferred that at least one or all contact devices are designed as at least one chain and / or at least one conveyor belt, wherein preferably the glass tube elements are movable, supportable, moved and / or supported along the movement path by the chain or conveyor belt.

[0167] The chain or conveyor belt can have a special contact geometry to control the cooling process.

[0168] It is also possible to use the chain or conveyor belt as a means of transport for moving the glass tube elements at the same time. This is very economical.

[0169] In one embodiment, alternatively or additionally, it is preferred that for at least one aspect of the contact devices, such as the number, diameter, size, spatial position, center distance, thermal conductivity and / or design, in particular caster design, conveyor belt design or chain design, a plurality of contact devices can be divided into at least two groups. For each group, it is preferred that the values for the respective aspects are selected from the above-mentioned respective options, respectively.

[0170] If different types of contact devices are used, the interaction between the cooling device and the glass tube elements can be adjusted to the specific requirements.

[0171] For example, for a plurality of contact devices (e.g. 5 contact devices), a first group of contact devices A (e.g. 2 contact devices) has contact devices with design A1 (e.g. casters), diameter A2 (e.g. 5 cm), center distance A3 (e.g. 6 cm), spatial position A4 (e.g. centers measured at 0 cm and 6 cm from a certain reference point) and thermal conductivity A5 (e.g. 30 W / (m x K)). A second group of contact devices B (e.g. 3 contact devices) has contact devices with design B1 (e.g. casters), diameter B2 (e.g. 2 cm), center distance B3 (e.g. 3 cm), spatial position B4 (e.g. centers measured at 10 cm, 13 cm and 16 cm from the reference point) and thermal conductivity B5 (e.g. 40 W / (m x K)).

[0172] In other words, using all possible combinations of parameters for each group can improve the manufacturing process, and thus the performance of the glass tube element.

[0173] In one embodiment, alternatively or additionally, it is preferred that the glass tube element is rotated at least during its cooling, preferably the glass tube element is rotated at least during its cooling (1) according to a movement speed; (2) with a rotation speed of more than 1 revolution per second, preferably more than 5 revolutions per second; and / or (3) more than 0.5 times, preferably more than 1 time, more than 3 times, more than 5 times or more than 10 times during its passage through the cooling device.

[0174] Rotating the glass tube element can enable an interaction between the contact devices and the glass tube element around the entire circumference of the glass tube element. In particular, rotating allows for a circumferential interaction with only one single contact device, of course, more than one contact device can also be used. In this way, the performance of the glass tube element can be improved.

[0175] If one or more rotations are performed during the passage of the glass tube element through the cooling device, it can be ensured that the glass tube element has indeed been subjected to at least one complete 360-degree interaction.

[0176] However, it has been found that, in certain cases, it is alternatively or additionally preferred that no rotation is performed at all.

[0177] This problem is solved according to a second aspect of the present application, wherein a glass tube element, in particular a glass tube element according to the first aspect of the present application, is proposed for use as at least one essential component of at least one pharmaceutical container, such as a vial, a cartridge, an ampoule or a syringe.

[0178] It has surprisingly been found that a glass tube element according to the inventive concept is intended for use in a pharmaceutical container due to the improved performance.

[0179] Thus, the glass tube element can be very useful in the manufacturing process of a pharmaceutical container. For example, it can be used in the manufacturing process of a vial or a syringe.

[0180] The problem is solved in accordance with a third aspect of the present application, wherein a method for producing a glass tube element, in particular a glass tube element according to the first aspect of the present application, is proposed, the method comprising the following steps:

[0181] - providing a glass tube strand;

[0182] - guiding the glass tube strand along a defined, preferably horizontally extending movement path with a defined movement speed during cooling of the glass tube strand, wherein at least one cooling device is arranged along at least one portion of the movement path, the surface temperature of the glass tube strand being temporarily between Tg- 50°C and Tg+ 150°C when the glass tube strand passes through and / or along the cooling device;

[0183] - acting on at least one portion of the glass tube strand passing through and / or along the cooling device at least temporarily and / or regionally by means of the cooling device to set a locally changed cooling rate of the glass tube strand, such that different regions are established on the shell of the glass tube strand, wherein the stress value of at least one first region lies within a first range and the stress value of at least one second region lies within a second range; and

[0184] - manufacturing the glass tube element using the glass tube strand.

[0185] Surprisingly, it has been found that the geometrical parameters, thus the first, second and overall quality of the glass tube element can be improved, if the glass tube strand is treated in a special way during its cooling. It has turned out that influencing the cooling process by locally changing the cooling rate of the glass tube strand leads to advantageous results.

[0186] Preferably, the cooling rate is changed at the outer surface of the glass tube element. However, it is also possible to change the cooling rate elsewhere, for example within the shell of the glass tube element.

[0187] If the movement speed and the movement path are defined, a higher control of the cooling process can be achieved. In particular, it has been found that a straight or at least close to straight movement path is more suitable for a uniform and reproducible interaction.

[0188] The inventors believe that the above-mentioned treatment using the cooling device and other arrangements, respectively, during cooling controls the structure of the glass tube element, in particular the structure above, below and / or near the outer surface of the glass tube element, thereby improving the geometrical properties of the glass tube element.

[0189] In one embodiment, alternatively or additionally, it is preferred that the cooling device has at least one contact device, wherein the contact device at least from time to time and / or regionally contacts, preferably directly contacts, at least one region of the outer surface of the glass tube element.

[0190] It has surprisingly been found that the provision of a contact device allows to control the locally present cooling rate on the surface, in particular the outer surface, of the glass tube element in a precise, reliable and comfortable manner. It is also possible to control the moment at which the contact device contacts the glass tube element. This can be controlled, for example, by means of the respective spatial arrangement of the contact device within the cooling device, such that the glass tube element passes along the respective contact device at an earlier or later moment. Of course, it is preferred that not the entire contact device has to be in contact with the glass tube element, but this is possible. It can be sufficient if only a portion thereof is in contact with the glass tube element. Of course, it is preferred that not the entire outer surface of the glass tube element has to be in contact with the contact device, but this is possible. It can be sufficient if only a region of the outer surface of the glass tube element is in contact with the contact device.

[0191] These design parameters allow to effectively control the degree of interaction between the contact device and the glass tube line. The earlier the contact between the contact device and the glass tube element, the longer the contact time, the broader the contact range, the more interaction can take place between the two, and thus the more cooling can take place.

[0192] In a further preferred embodiment, alternatively or additionally, the cooling device has at least one fluid distributor device, which is designed to provide, preferably at least from time to time and / or regionally, a fluid, for example water, mist and / or air, preferably compressed air, on at least one region of the outer surface of the glass tube line.

[0193] The use of a fluid can improve the control of the cooling process of the glass tube line. In this way, in particular, a drastic change in temperature can be achieved in a short time. This can also be used to support the cooling process carried out by the contact device.

[0194] Preferably, the fluid distributor is at least partially designed in the form of at least one annular nozzle. This allows a uniform (and circumferential) interaction between the fluid and the glass tube line to be achieved. In other words, using an annular nozzle can cover the entire outer surface of the glass tube line. It has proven that this improves the straightness of the glass tube element at least in sections.

[0195] In a preferred embodiment, the fluid distributor is used as part of at least one air bearing and / or in combination with at least one contact device. This makes it possible to achieve an interaction between the glass tube element and the contact device with reduced or even no direct contact. This can reduce the contamination effect.

[0196] In one embodiment, alternatively or additionally, it is preferred that at least one or all of the contact devices are designed as at least one caster, wherein preferably the glass tube element is movable, supportable, moved along the movement path and / or supported by the caster.

[0197] The use of casters has a great degree of design freedom and flexibility. For example, different dimensions, in particular different diameters, different materials, different thermal conductivities and different contact areas can be easily realized.

[0198] For example, the caster has at least one V-shaped recess at least in one cross-sectional plane, preferably in a plane comprising the central axis of the caster.

[0199] The recess allows two contact areas between the caster and the glass tube element to be realized at the same time. In other words, since the glass tube element can be supported by the caster within the space provided by the "V", the caster provides two side walls that can come into contact with the glass tube element.

[0200] The caster can also be used as a transport means for simultaneously moving the glass tube element. This is very economical.

[0201] It is recognized that one or more casters can also be replaced by a corresponding number of rollers.

[0202] The present inventive concept thus clearly shows that by changing the spatial absolute and relative position, number and / or diameter of the contact devices, in particular the casters, different interaction patterns can be obtained, which allow the interaction between the cooling device and the glass tube element to be optimized. The inventors have recognized that this interaction in turn can result in a high-quality glass tube element. Accordingly, the respective parameters can be chosen in a comfortable manner for different purposes and requirements. This in turn allows the ovality and straightness of the glass tube element to be modified and improved.

[0203] Of course, the cooling process, and thus the interaction pattern, the ovality and straightness of the glass tube element, and thus the quality of the glass tube element, can also be changed by changing the movement speed of the glass tube element. Likewise, the cooling process, and thus the interaction pattern, the ovality and straightness of the glass tube element, and thus the quality of the glass tube element, can also be changed by changing the rotation speed of the glass tube element.

[0204] Further aspects of the present invention will be described in detail below.

[0205] Measuring optical properties

[0206] The principles of the optical measurement according to the present invention will be described in further detail below.

[0207] Figure 1A cross-sectional view of a glass tube element 1 according to the invention is shown. The glass tube element 1 has a housing 3 having an inner surface 5 and an outer surface 7. The outer surface 7 is the surface of the housing 3 facing away from the lumen 8. This plane is perpendicular to the main extension direction of the glass tube element 1. The glass tube element is immersed in a fluid 9. It is sufficient if the fluid 9 surrounds the glass tube element 1 such that only the outer surface 7 is in contact with the fluid 9. However, as Figure 1 As shown, fluid 9 may also be inside the hollow cylinder, and therefore it also contacts the inner surface 5.

[0208] Preferably, the fluid has the same optical density as the glass material. The term "same optical density" here means that the optical density of the fluid and the optical density of the glass material match to three decimal places. Therefore, if the optical density of the fluid and the optical density of the glass material match to three decimal places, the fluid has the same optical density as the glass material.

[0209] For example, according to this definition, optical densities of 1.3456 and 1.3454 are the same. For example, according to this definition, optical densities of 1.3456 and 1.3457 are also the same. The fluid may include at least one paraffin or at least one oil having a suitable optical density, or as represented thereto.

[0210] Light ray 11a extends along a measurement path that is perpendicular to the main extension direction of the glass tube element 1. This measurement path... Figure 1 The plane shown in the attached figure is tangent to the surface of the shell 3 that is away from the cavity, i.e., tangent to the outer surface 7. Figure 1 In this context, the measurement path can be located in a cylindrical coordinate system ( Figure 1 The contact surface (i.e., outer surface 7) is located at a position within (not shown in the image). A cylindrical coordinate system is fixedly attached to the glass tube element 1, and its origin is located at the central axis of the glass tube element 1 by means of its height, radius, and azimuth. Figure 1 (Not shown in the image). Assume that in... Figure 1 At 12 o'clock, with an azimuth of zero degrees (and increasing clockwise), light ray 11a contacts the outer surface 7 at a position with an azimuth of 270 degrees.

[0211] If known optical measuring equipment is used ( Figure 1By analyzing the light rays 11a after their passage through the glass tube element 1, in particular through the shell 3, it is possible to determine a specific value of the optical delay experienced by the light rays 11a within the glass tube element, in particular. This optical delay is due to the birefringence in the glass tube element 1, which in turn depends on the mechanical stress state in the respective regions of the shell 3 through which the light rays 11a pass. The optical delay can thus be considered as a measure for the stresses within the surface of the shell 3, for example within the outer surface 7 of the shell 3. For different measurements, different positions of the contact of the measurement path with the outer surface 7 of the shell 3 in the same cross-sectional plane, i.e. at the same height in the coordinate system, are chosen. In other words, the azimuthal angle of the position is changed for each measurement.

[0212] Thus, if for different measurements the azimuthal angle is changed, for example from 0 degrees to 359 degrees in steps of 1 degree (for example, in the case of the glass tube element 1 of Fig. 1, by rotating around the central axis of the glass tube element), it is possible to easily and reliably determine the optical delay of the light rays 11a for different azimuthal angles, i.e. for different positions of the contact of the measurement path with the outer surface 7. From these measurements it is easy to obtain the size of the range into which the values of the optical delay for different azimuthal angles fall. For example, if for five measurements at five different azimuthal angles the values of the optical delay are 40 nm, 45 nm, 50 nm, 55 nm and 60 nm, respectively, the corresponding range is 40 nm and 60 nm, and the size of the range is (60 nm - 40 nm) = 20 nm. Figure 1

[0213] For example, for the optical measurements, the light rays, such as the light rays 11a described above, have a linear polarization which encloses an angle of 45 degrees with the central axis of the glass tube element. For example, the light wavelength of the light rays is 630 nm, 633 nm or 635 nm. For example, the ambient temperature is room temperature.

[0214] Other glass properties

[0215] ​The coefficient of linear thermal expansion (CTE) is a measure that characterizes the expansion behavior of a glass upon experiencing a certain temperature change. The CTE can be the average coefficient of linear thermal expansion in the temperature range from 20 °C to 300 °C as defined in DIN ISO 7991 :1987. The lower the CTE, the less the glass will expand due to a temperature change. Therefore, the CTE of the glass of the wall of the glass tube element of the present application is preferably less than 12 ppm / K, more preferably less than 10.0 ppm / K, more preferably less than 9.0 ppm / K, more preferably less than 8.0 ppm / K, more preferably less than 7 ppm / K, more preferably less than 6.5 ppm / K in the temperature range from 20 °C to 300 °C. However, the CTE should also not be too low. Preferably, the CTE of the glass of the present application is more than 3 ppm / K, more preferably more than 4 ppm / K, more preferably more than 5 ppm / K, more preferably more than 6 ppm / K in the temperature range from 20 °C to 300 °C. In order to make the glass well suited for chemical tempering, the glass can comprise a relatively high amount of alkali ions, preferably sodium ions. However, this increases the average coefficient of linear thermal expansion CTE in the temperature range from 20 °C to 300 °C. Preferably, the CTE of the glass of the wall of the glass tube element of the present application is higher than 7 x 10 -6 / °C, more preferably higher than 8 x 10 -6 / °C, more preferably higher than 9 x 10 -6 / °C. However, a high CTE also complicates the production of the glass by direct hot forming. Therefore, the CTE of the glass is preferably lower than 13 x 10 -6 / °C.

[0216] The transition temperature of the glass for the wall of the glass tube element can be higher than 300 °C, 500 °C, 520 °C, 530 °C, 550 °C, or even higher than 600 °C. The transition temperature of the glass for the wall of the glass tube element can be lower than 900 °C, 800 °C, 700 °C, 650 °C, or 630 °C. Generally, a low transition temperature generally includes lower energy costs for melting the glass and processing. Additionally, if the transition temperature is low, the glass will generally have a lower fictive temperature. Therefore, if the transition temperature is higher, the glass will be less likely to undergo irreversible thermal contraction during an optional chemical tempering process.

[0217] The glass tube element should be manufactured with high purity and should have good resistance, in particular against alkaline solutions. Resistance against alkaline solutions is very important for the use of the glass tube element. Alkaline solutions are often used as cleaning agents for the glass tube element. Preferably, the glass tube element has a resistance against alkalis according to DIN ISO 695:1994 of class A3, class A2 or even class Al. Resistance against alkalis means resistance against attack by aqueous alkaline solutions at 50°C. High chemical stability and / or high resistance against alkalis greatly reduce the precipitation or leakage of substances from the glass tube element, for example when the glass tube element is in contact with liquids such as fruit juice, tea or dishwasher water. Leakage of substances out of the glass tube element changes the chemical composition of the surface of the glass of the leaked substances. This can have a negative effect on the appearance and should therefore be avoided.

[0218] The average surface roughness (R a ) is a measure of the surface texture. It is quantified by the vertical deviations of the actual surface from its ideal form. Typically, the amplitude parameters characterize the surface based on the vertical deviations of the roughness profile from the mean line. R a is the arithmetic mean of the absolute values of these vertical deviations. The roughness can be measured with an atomic force microscope. The inner surface and / or the outer surface of the glass tube element preferably has an average surface roughness R a of less than 30 nm, less than 10 nm, less than 5 nm, less than 2 nm, less than 1 nm. In some embodiments, the surface roughness R a is less than 0.5 nm. A smaller inner surface and / or outer surface roughness reduces the amount of residual fluid. Residual fluid within the glass tube element can cause the growth of microorganisms, which can harm the health of animals or humans. Furthermore, a smaller outer surface roughness feels more comfortable when holding the glass tube element in the hand. The mentioned roughness values can be obtained by fire polishing of the glass.

[0219] The glass composition

[0220] The glass used for the wall of the glass tube element is not limited to a specific glass composition. The glass can be selected from the group consisting of soda-lime glass, borosilicate glass, alkali-resistant glass and aluminosilicate glass. Alternatively, a borosilicate glass is used.

[0221] Preferably, the glass of the glass tube element comprises the following ingredients in the specified amounts (in wt.%):

[0222] Element Content (wt..%) SiO2 40 to 85 Al2O3 0 to 25 Na2O 0 to 18 K2O 0 to 15 MgO 0 to 10 B2O3 0 to 22 Li2O 0 to 10 ZnO 0 to 5 CaO 0 to 16 BaO 0 to 12 ZrO2 0 to 5 CeO2 0 to 0.5 SnO2 0 to 3 P2O5 0 to 15 Fe2O3 0 to 1.5 TiO2 0 to 10 SrO 0 to 1 F 0 to 1 Cl 0 to 1

[0223] Si02 is a relevant network former that can be used in the glasses used in the present application. Thus, the glass can comprise at least 60 wt.% of Si02. More preferably, the glass comprises at least 62 wt.%, at least 65 wt.%, at least 68 wt.%, more than 70 wt.% or even more than 75 wt.% of Si02. However, the content of Si02 in the glass should not be too high, otherwise the fusibility can be affected. The content of Si02 in the glass can be limited to at most 85 wt.% or at most 82 wt.%. In embodiments, the content of Si02 in the glass is from 60 wt.% to 85 wt.% or > 65 wt.% to 75 wt.%.

[0224] B203 can be used to enhance the network via the form of [B04] tetrahedra by increasing the bridging oxides in the glass. It also helps to improve the damage resistance of the glass. However, B203 should not be used in large amounts in the glass as it can reduce the ion exchange performance. Furthermore, the addition of B203 can significantly reduce the Young's modulus. The glass can comprise from 0 to 20 wt.%, preferably from 0 to 15 wt.%, preferably from 0.1 to 13 wt.% of B203. In embodiments, the glass preferably comprises at least 5 wt.%, more preferably at least 7 wt.% or at least 10 wt.% of B203.

[0225] P205 can be used in the glasses of the present application to help reduce the melting viscosity by forming [P04] tetrahedra, which can significantly reduce the melting point without sacrificing the resistance to crystallization. Limited amounts of P205 do not significantly increase the change in geometry, but can significantly improve the melting, forming performance and ion exchange (chemical tempering) performance of the glass. However, if a large amount of P205 is used, the geometric expansion after chemical tempering can be greatly increased. Thus, the glass can comprise from 0 to 4 wt.% or from 0 to 2 wt.% of P205. In some embodiments, the glass is free of P205.

[0226] It is believed that Al203 can readily form tetrahedral coordination when the basic oxide ratio content is equal to or higher than Al203. The [A104] tetrahedral coordination can help to establish a more compact network together with the [Si04] tetrahedra, thereby reducing the change in geometry of the glass. The [A104] tetrahedra can also significantly enhance the ion exchange process during chemical tempering. Thus, the content of Al203 in the glass is preferably at least 0 wt.%, more preferably more than 1 wt.%, more preferably more than 4 wt.%. However, the content of Al203 should not be too high, otherwise the viscosity can be very high, which can impair the fusibility. Thus, the content of Al203 in the glass is preferably at most 20 wt.%, at most 12 wt.% or at most 10 wt.%. In preferred embodiments, the content of Al203 in the glass is from 0 to 20 wt.%, from 1 to 12 wt.%, from 4 to 10 wt.%.

[0227] TiO2may also form [TiO4], thus helping to build the glass network and favorably increasing the acid resistance of the glass. However, the content of TiO2in the glass should not be too high. High concentrations of TiO2may act as nucleating agents, thus leading to crystallization during the manufacturing process. Preferably, the content of TiO2in the glass is 0 to 10 wt.%, or up to 7 wt.%. In some embodiments, the glass comprises at least 0.5 wt.%, at least 2 wt.%, or at least 3 wt.% TiO2. In embodiments, the glass is free of TiO2.

[0228] ZrO2has the function of lowering the CTE and increasing the alkali resistance of the glass. It can increase the melting viscosity, which can be suppressed by using P2O5. Like alkalis, Zr 4+ is also a network modifier. In addition, ZrO2is very helpful in increasing the Young’s modulus. Preferably, the content of ZrO2in the glass is 0 to 5 wt.%, or up to 2 wt.%. The glass can be free of ZrO2. In some embodiments, the glass comprises at least 0.1 wt.%, or at least 0.2 wt.% ZrO2.

[0229] Alkaline oxides R2O (Li2O + Na2O + K2O + Cs2O) can be used as network modifiers to provide sufficient oxygen anions to form the glass network. Preferably, the content of R2O in the glass is greater than 4 wt.%, or greater than 12 wt.%. However, the content of R2O in the glass should not be too high, otherwise the chemical durability and chemical toughness can be compromised. Preferably, the glass comprises a content of R2O of up to 30 wt.%, up to 25 wt.%, or up to 20 wt.%. Other embodiments are free of alkaline oxides, or at least free of Na2O, K2O, Cs2O, and / or Li2O.

[0230] Li2O helps to increase the Young’s modulus and lower the CTE of the glass. Li2O also has a large impact on ion exchange. Surprisingly, lithium-containing glasses have a small geometric change. Thus, the content of Li2O in the glass can be set to at least 0 wt.%, or more than 5 wt.%, or even more than 10 wt.%. However, the content of Li2O should not be too high, otherwise the chemical durability and chemical toughness can be compromised. Preferably, the content of Li2O in the glass is no more than 24 wt.%, less than 15 wt.%, or even 0 wt.%.

[0231] Na2O can be used as a network modifier. However, the content of Na2O should not be too high, otherwise the chemical durability and chemical toughness can be compromised. The content of Na2O in the glass is preferably 0 to 15 wt.%, preferably 2 to 15 wt.%. In preferred embodiments, the content of Na2O in the glass is at least 5 wt.%, at least 8 wt.%, or at least 10 wt.%.

[0232] K2O can be used as a network modifier. However, the content of K2O should not be too high, otherwise the chemical durability and chemical toughness can be compromised. Preferably, the content of K2O in the glass is from 0 to 15 wt.%, or > 0.5 to 7 wt.%. The glass can also be free of K2O.

[0233] Preferably, the glass comprises more Na2O than K2O. Thus, preferably, the molar ratio of Na2O / (Na2O + K2O) is from > 0.5 to 1.0, from > 0.6 to 1.0, from > 0.7 to 1.0, or from > 0.8 to 1.0.

[0234] Preferably, the total content of Li2O and Na2O in the glass is greater than 10 mol-%, or greater than 15 mol-%. However, the content of Li2O and Na2O in the glass should not be too high. Preferably, the total content of Li2O and Na2O in the glass is at most 25 mol-%, or at most 20 mol-%.

[0235] The glass can also comprise alkaline earth metal oxides as well as ZnO (collectively referred to in this specification as "RO"). The alkaline earth metals and zinc can be used as network modifiers. Preferably, the glass comprises RO in a content of from 0 to 20 wt.%, preferably from 0 to 15 wt.%. In some embodiments, preferably, the glass comprises RO in a content of at least 0.5 wt.%, more preferably at least 1 wt.%, more preferably at least 5 wt.%. Preferred alkaline earth metal oxides are selected from MgO, CaO, SrO, and BaO. More preferably, the alkaline earth metal is selected from MgO and CaO. More preferably, the alkaline earth metal is MgO. Preferably, the glass comprises MgO in a content of from 0 to 10 wt.%. In some embodiments, the glass comprises at least 0.5 wt.%, at least 1 wt.%, or at least 2 wt.% MgO. Preferably, the glass comprises CaO in a content of from 0 to 16 wt.%, preferably from 0 to 13 wt.%, preferably from 0 to 10 wt.%. In some embodiments, the glass comprises at least 0.5 wt.%, at least 1 wt.%, at least 5 wt.%, at least 10 wt.%, or at least 12 wt.% CaO. Preferably, the glass comprises BaO in a content of from 0 to 12 wt.%, preferably from 0 to 10 wt.%. In some embodiments, the glass comprises at least 0.5 wt.%, at least 2 wt.%, or at least 7 wt.% BaO. The glass can also be free of BaO, MgO, and / or CaO.

[0236] Preferably, the glass comprises ZnO in an amount of from 0 to 5 wt.%. In some embodiments, the glass comprises ZnO in an amount of at least 0.5 wt.%, at least 1 wt.% or at least 2 wt.%. In other embodiments, the glass is free of ZnO. Preferably, the total amount of MgO and ZnO in the glass is from 0 to 10 wt.%. In some embodiments, the total amount of MgO and ZnO in the glass is at least 0.5 wt.%, more preferably at least 1 wt.%, more preferably at least 2 wt.%.

[0237] Finally, when forming the glass by mixing different types of oxides, the overall effect should be considered to make the glass relatively low in expansion, which is supported by a high densification of the glass network. This means that, in addition to [SiO4] tetrahedra and [BO4] tetrahedra, [AlO4] tetrahedra or [PO4] tetrahedra are expected to connect [SiO4] more efficiently than other types of polyhedra. In other words, for example, [BO3] trihedra and [AlO6] octahedra are not preferred. This means that, preferably, sufficient oxygen anions are provided by adding appropriate amounts of metal oxides, such as R2O and RO.

[0238] Preferably, the glass comprises SnO2 in an amount of from 0 to 3 wt.%. More preferably, the glass is free of SnO2. Preferably, the glass comprises Sb2O3 in an amount of from 0 to 3 wt.%. More preferably, the glass is free of Sb2O3. Preferably, the glass comprises CeO2 in an amount of from 0 to 3 wt.%. A high amount of CeO2 is disadvantageous because CeO2 has a coloring effect. Therefore, more preferably, the glass is free of CeO2. Preferably, the glass comprises Fe2O3 in an amount of from 0 to 3 wt.%. More preferably, the glass is free of Fe2O3.

[0239] The glasses described herein are described as having a composition of different components. This means that the glass comprises these components without excluding other components not mentioned. However, in preferred embodiments, the glass consists of the components mentioned in this specification in an amount of at least 95%, more preferably at least 97%, more preferably at least 99%. In most preferred embodiments, the glass consists essentially of the components mentioned in this specification.

[0240] Optionally, coloring oxides can be added, such as, for example, Nd2O3, Fe2O3, CoO, NiO, V2O5, MnO2, CuO, CeO2, Cr2O3.

[0241] 0 to 2 wt.% of As2O3, Sb2O3, SnO2, SO3, Cl and / or F can also be added as refining agents. 0 to 5 wt.% of rare earth oxides can also be added to impart optical or other functionality to the glass wall.

[0242] As used herein, the terms "free of X" and "free of ingredient X" or "0% X" mean that the glass does not substantially contain the ingredient X, i.e. such ingredient can be present in the glass at most as an impurity or contaminant, but is not added to the glass composition as a separate ingredient. This means that the ingredient X is not added in a necessary amount. A non-necessary amount according to the present application is an amount of less than 100 ppm, preferably less than 50 ppm, more preferably less than 10 ppm. Preferably, the glasses described herein do not substantially contain any ingredient not mentioned in the present specification.

[0243] In an embodiment, the glass for a glass tube element comprises the following composition in weight percent:

[0244] Element Content (wt..%) SiO2 40 to 85 Al2O3 0 to 25 Na2O 2 to 18 K2O 0 to 15 MgO 0 to 10 B2O3 0 to 15 Li2O 0 to 10 ZnO 0 to 5 CaO 0 to 10 BaO 0 to 5 Zr02 0 to 5 CeO2 0 to 0.5 SnO2 0 to 3 P2O5 0 to 15 Fe2O3 0 to 1.5 TiO2 0 to 10 SrO 0 to 1 F 0 to 1 Cl 0 to 1

[0245] In an embodiment, the glass for a glass tube element has the following composition in weight percent:

[0246] Element Content (wt..%) SiO2 55 to 65 Al2O3 10 to 20 Na2O 0 to 3 [K2O] 0 to 3 MgO 0 to 5 B2O3 0 to 6 Li2O 0 to 3 ZnO 0 to 3 CaO 7 to 15 BaO 5 to 10 ZrO2 0 to 3 CeO2 0 to 0.5 SnO2 0 to 3 P2O5 0 to 3 Fe2O3 0 to 1.5 TiO2 0 to 3 SrO 0 to 1 F 0 to 1 Cl 0 to 1

[0247] In an embodiment, the glass for a glass tube element has the following composition in weight percent:

[0248] Element Content (wt..%) SiO2 65 to 85 Al2O3 0 to 7 Na2O 0.5 to 10 K2O 0 to 10 MgO 0 to 3 B2O3 8 to 20 Li2O 0 to 3 ZnO 0 to 3 CaO 0 to 3 BaO 0 to 3 ZrO2 0 to 3 CeO2 0 to 0.5 SnO2 0 to 3 P2O5 0 to 3 Fe2O3 0 to 1.5 TiO2 0 to 3 SrO 0 to 1 F 0 to 1 Cl 0 to 1

[0249] In an embodiment, the glass for a glass tube element has the following composition in weight percent:

[0250] Element Content (wt..%) SiO2 60 to 80 Al2O3 0 to 5 Na2O 10 to 18 K2O 0 to 5 MgO 0 to 5 B2O3 0 to 5 Li2O 0 to 3 ZnO 0 to 3 CaO 2 to 10 BaO 0 to 5 ZrO2 0 to 3 CeO2 0 to 0.5 SnO2 0 to 3 P2O5 0 to 3 Fe2O3 0 to 1.5 TiO2 0 to 3 SrO 0 to 1 F 0 to 1 Cl 0 to 1

[0251] Optional additional treatments of the glass tube element

[0252] For optional chemical tempering, the glass can be immersed in a salt bath. The salt bath can comprise sodium and / or potassium salts. The salt used for the salt bath can comprise Na, K or Cs nitrate, sulfate or chloride salts, or a mixture of one or more thereof. Preferred salts are NaN03, KN03, NaCl, KC1, K2S04, Na2S04, Na2C03, K2C03, or a combination thereof. Additives such as NaOH, KOH and other sodium or potassium salts can also be used to better control the ion exchange speed, compressive stress and DoL during chemical tempering. In an embodiment, the salt bath comprises KN03, NaN03, CsN03, or a mixture thereof.

[0253] The temperature during chemical tempering can be in the range of 320 °C to 700 °C, 350 °C to 500 °C, or 380 °C to 450 °C. If the tempering temperature is very low, the tempering rate will be low. Therefore, preferably, the chemical tempering is performed at a temperature higher than 320 °C, more preferably higher than 350 °C, more preferably higher than 380 °C, more preferably at least 400 °C. However, the tempering temperature should not be too high, as too high temperatures result in a strong relaxation of the compressive stress and a low compressive stress. Preferably, the chemical tempering is performed at a temperature lower than 500 °C, more preferably lower than 450 °C.

[0254] The time of chemical tempering can be in the range of from 5 minutes to 48 hours, from 10 minutes to 20 hours, from 30 minutes to 16 hours, or from 60 minutes to 10 hours. In preferred embodiments, the duration of chemical tempering is 0.5 to 16 hours. The chemical tempering can be performed in a single step or in multiple steps, in particular two steps. If the duration of tempering is very short, the resulting DoL can be low. If the tempering time is very long, the CS can be very relaxed. In a multiple step tempering procedure, the duration of each tempering step is preferably between 0.05 and 15 hours, more preferably between 0.2 and 10 hours, more preferably between 0.5 and 6 hours, more preferably between 1 and 4 hours. The total time of chemical tempering, in particular the total time of two or more individual tempering steps, is preferably between 0.01 and 20 hours, more preferably between 0.2 and 20 hours, more preferably between 0.5 and 15 hours, more preferably between 1 and 10 hours, more preferably between 1.5 and 8.5 hours. The glass tube element can be treated with chemical tempering such that it has a DoL of at least 10 pm or at least 20 pm. In some embodiments, the DoL can be up to 80 pm, up to 60 pm, or up to 50 pm.

[0255] In some embodiments, the glass is chemically tempered using a mixture of KNO3and NaNO3. In embodiments, the mixture comprises less than 50 mol% NaNO3, less than 30 mol% NaNO3, less than 20 mol% NaNO3, less than 10 mol% NaNO3, or less than 5 mol% NaNO3. In some embodiments, the glass is chemically tempered using a mixture of KNO3and CsNO3. In embodiments, the mixture comprises less than 50 mol% CsNO3, less than 30 mol% CsNO3, less than 20 mol% CsNO3, less than 10 mol% CsNO3, or less than 5 mol% CsNO3. The remainder can be KNO3.

[0256] Chemical tempering with KNO3and NaNO3is accomplished by using a mixture of KNO3and NaNO3or by performing separate tempering steps with substantially pure NaNO3and substantially pure KNO3. Also in the embodiments where the glass is chemically tempered with a mixture of KNO3and NaNO3, preferably two different consecutive tempering steps are performed. Preferably, the proportion of KNO3in the mixture used for the second tempering step is higher than the proportion of KNO3in the mixture used for the first tempering step. Chemical tempering can include multiple steps with various concentrations of alkali ions in the salt bath to achieve better tempering performance.

[0257] Tempering can be achieved by immersing the glass in a molten salt bath of the above-mentioned salts or by covering the glass with a paste containing the above-mentioned ions, such as potassium ions and / or other alkali ions, and heating to high temperatures for a period of time. The larger alkali ions in the salt bath or paste exchange with the smaller alkali ions in the glass article, and surface compressive stress is created as a result of the ion exchange.

[0258] The chemically tempered glass tube element of the present invention can be obtained by at least chemically tempering the wall of the glass tube element of the present invention. The tempering process can be accomplished by partially or completely immersing the glass tube element, glass tube, glass wall or any intermediate glass article in the above-mentioned salt bath or subjecting it to a salt paste. The monovalent ions in the salt bath have a larger radius than the alkali ions inside the glass. After ion exchange, the larger ions in the glass network squeeze the glass, creating a compressive stress. After ion exchange, the strength and flexibility of the glass are unexpectedly significantly improved. In addition, the compressive stress resulting from chemical tempering can increase the scratch resistance of the glass tube element. Because scratches can affect the mechanical and chemical resistance of the glass surface as well as the optical appearance, increasing scratch resistance is particularly important for glass tube elements.

[0259] After chemical tempering, the glass tube is removed from the salt bath and then washed with water and dried. A compressive stress layer is formed on the outer surface and / or the inner surface of the tempered glass tube. Correspondingly, a tensile stress is formed in the core of the glass tube wall.

[0260] It is known that, preferably, any existing stress layer or stress pattern can overlap with the stress layer or stress pattern introduced by the subsequent chemical tempering. In particular, the depth of the stress layer / pattern introduced by the chemical tempering can be, for example, 50 pm, while the other stress layer / pattern can extend over the entire depth of the glass material. This can lead to the situation that any previous stress layer / pattern or parts thereof are in or at least in certain volume / surface areas that are biased by a certain value according to the chemical tempering process.

[0261] Tempering

[0262] During the manufacturing process, one or more types of tempering can be applied to the glass tube element. For example, the glass tube element can be chemically and / or physically tempered. Both types of tempering are described in detail elsewhere in this application.

[0263] The threshold diffusivity D of the glass tube element wall is preferably at least 1.5 μm 2 per hour, more preferably at least 4 μm 2 per hour. The chemical tempering performance of a glass can be described by the threshold diffusivity D. The threshold diffusivity D can be calculated from the measured depth of layer (DoL) and ion exchange time (IET) according to the following relationship: DoL = ~1.4 sqrt(4 x D x IET). For example, the threshold diffusivity can be measured when tempering the glass with KNO3 at 410°C for 8 hours. The glass used for the glass tube element can have excellent chemical tempering performance, which makes the production very economical. Thus, the glass can have a threshold diffusivity D of at least 1.5 μm 2 per hour. Preferably, the threshold diffusivity D of the glass of the present application is at least 4 μm 2 per hour, at least 6 μm 2 per hour, at least 8 μm 2 per hour, at least 10 μm 2 per hour, at least 12 μm per hour, at least 14 μm 2 per hour, at least 16 μm 2 per hour, at least 18 μm 2 per hour, at least 20 μm 2 per hour, at least 25 μm 2 per hour, at least 30 μm 2 per hour, at least 35 μm 2 per hour, or even at least 40 μm 2 per hour. In embodiments, the threshold diffusivity is up to 60 μm 2 per hour or 50 μm 2 per hour.

[0264] In some embodiments, chemical tempering is employed.

[0265] Cutting mechanism

[0266] In preferred embodiments, at least one of the three cutting mechanisms can be used to manufacture the glass tube elements, i.e. to prepare each glass tube element of the desired length from a longer glass element (e.g. a glass tube line): 1. scraping, which means that the longer glass element is scraped and broken at the desired location to obtain the individual glass tube element, this technique can also be referred to as "score breaking"; 2. sawing, which means that the longer glass element is sawn at the desired location to obtain the individual glass tube element; 3. laser cutting, which means that the individual glass tube element is obtained by cutting the individual segment from the longer glass element by means of a laser.

[0267] In preferred embodiments, the laser cutting technique is used.

[0268] Polishing

[0269] In preferred embodiments, all or at least one or more portions of the glass tube element can be fire polished. This means that, for example during or after drawing the glass tube, the material is exposed to a flame or heat, which can cause the surface to become smooth. Preferably, at least the end portions of the glass tube element are fire polished. More preferably, the entire glass tube element, at least its outer surface, is fire polished. Reference is also made to the above discussion regarding surface roughness. BRIEF DESCRIPTION OF DRAWINGS

[0270] Various aspects of the application will become apparent to those skilled in the art from the following detailed description of the preferred embodiments, when read in light of the accompanying drawings, in which

[0271] Figure 1 A diagram showing a cross-sectional plane of a glass tube element 1 according to the present application is shown;

[0272] Figure 2a A first glass tube element according to the present application is shown;

[0273] Figure 2b A second glass tube element according to the present application is shown;

[0274] Figure 3 A diagram showing a first exemplary production line is shown;

[0275] Figure 4 A diagram showing a second exemplary production line is shown;

[0276] Figure 5 A diagram showing a third exemplary production line is shown;

[0277] Figure 6 A diagram showing a fourth exemplary production line is shown;

[0278] Figure 7 A diagram showing a fourth exemplary production line is shown;

[0279] Figure 8 A schematic view of a fifth exemplary production line is shown. DETAILED DESCRIPTION

[0280] Figure 2a A first glass tube element 51 according to the application is shown.

[0281] It has a hollow cylindrical shape (not only a portion thereof, but the entire one) and a shell 53 which encloses a lumen 55. The length (i.e. from left to right) of the glass tube element 51 is 1.5 m.

[0282] A path 57a is defined or can be defined on the surface 59 of the shell 53 facing away from the lumen 55 which extends.

[0283] The path 57a follows on the entire outer circumference of the glass tube element 51 an intersection line which is obtained or can be obtained by the intersection of a plane perpendicular to the central axis of the glass tube element 51 with the surface 59 of the shell 53 facing away from the lumen 55. In other words, the path 57a is the intersection line.

[0284] The path 57a extends through at least one second region 61a (indicated with a circle) of the shell 53 in which the stress value lies within the second interval. The path 57a also extends through at least one first region 63a (indicated with another circle) of the shell 53 in which the stress value lies within the first interval.

[0285] In fact, the second region 61a and the first region 63a are surface regions (two-dimensional regions) of the outer surface 59 of the shell 53.

[0286] A plurality of parallel extending paths 57b and 57c of the defined type (i.e. parallel shifted variants of the path 57a) can be defined and / or identified in Figure 2a For each of the paths 57b, 57c, as described with respect to the path 57a, a second region 61b, 61c and a first region 63b, 63c can be identified.

[0287] A single second group of second regions 61a, 61b, 61c can be defined, wherein the second regions 61a, 61b, 61c of the second group are connected to each other by means of a connected second special region 65 of the shell 53. The stress value within the second special region 65 lies within the second interval.

[0288] A single first group of first regions 63a, 63b, 63c can be defined, wherein the first regions 63a, 63b, 63c of the first group are connected to each other by a connected first special region 67 of the shell 53. The stress value within the first special region 67 lies within the first interval.

[0289] Obviously, there is one first special region and one second special region.

[0290] On the developed cylindrical shell 53 (not shown separately), the second characteristic zone is designed in the form of at least one strip (the number of strips actually depends on the position at which the cylindrical shell 53 starts to develop). If there are several strips, then the strips are parallel to each other.

[0291] On the developed cylindrical shell 53, the first characteristic zone is designed in the form of at least two strips (the number of strips depends on the position at which the cylindrical shell 53 starts to develop). These strips are parallel to each other.

[0292] It is recognized that, in practice, the circular zones representing the first zones 63a, 63b, 63c (see Figure 2a ) can be chosen more or less arbitrarily, without departing from the scope of the invention, provided that they do not include at least a part of the second zone or of another first zone. For the definition of each first zone, it is essential that the stress value in this zone be within the first interval. This does not exclude that outside the first zone (for example, outside the first zones 63a, 63b, 63c) the stress value is still within the first interval. In practice, one or more zones outside the first zones can be located within the first characteristic zone (for example, the first characteristic zone 67), for which zones the stress value must also be within the first interval.

[0293] The same applies to the second zone and the second characteristic zone. It is recognized that, at least for Figure 2a , of course the second zones 61a, 61b, 61c are and can only be part of the second characteristic zone 65. Although Figure 2a indicates that the circles of the second zones 61a, 61b, 61c can still cover a part of the first characteristic zone 67, this is only for illustrative purposes, since in Figure 2a the second zones are too small to be represented by a circle alone.

[0294] For example, in Figure 2a , the first and second zones are defined along a path (for example, the path 57a) as described above, in any case the first zones do not directly follow the corresponding second zones. However, if the first zones are chosen differently, then at least in one direction along the path (for example, the path 57a) the first zones can directly follow the corresponding second zones.

[0295] When the glass tube element 51 is optically measured by means of at least one light ray extending along a measurement path, which extends along a measurement direction perpendicular to the main extension direction of the glass tube element 51 and which is tangential to the surface of the shell 53 facing away from the tube cavity, i.e. the outer surface of the shell 53, and which touches the surface at different locations, each of which has a different azimuth angle in a cylindrical coordinate system fixedly attached to the glass tube element 51 and with the origin of the cylindrical coordinate system on the central axis of the glass tube element 51, the optical delay values of the light rays obtained by the different measurements all fall within a range between 3 nm and 30 nm.

[0296] In fact, for the glass tube element 51, the different locations can be on one of the paths 57a, 57b or 57c (or on each of the paths moving parallel along the central axis of the glass tube element 51).

[0297] Figure 2b A second glass tube element 51’ according to the application is shown. Features which are structurally similar or identical to the glass tube element 51 are denoted by the same reference numerals, but with an apostrophe (’). Due to the similarities between the glass tube element 51 and the glass tube element 51’, only the differences need to be discussed here, and the rest can be referred to the discussion above with reference to the glass tube element 51. Figure 2a

[0298] The glass tube element 51’ has a plurality of second special regions 65a’, 65b’, 65c’, 65d’, 65e’, 65f’ (i.e. a number of six), and has a plurality of first special regions 67a’, 67b’, 67c’, 67d’, 67e’, 67f’ (i.e. a number of six).

[0299] The path 57a’ passes through a plurality of second regions (e.g. the second regions 61a-1’, 61a-2’ and 61a-3’) and a plurality of first regions (e.g. the first regions 63a-1’, 63a-2’ and 63a-3’). However, due to lack of space, only the first regions 63a-1’, 63a-2’ and 63a-3’ are denoted by circles, and the first and second regions on the back of the glass tube element 51’ are not marked at all.

[0300] The same task can be performed for the parallel moving paths (e.g. the paths 57b’ and 57c’). However, in order to keep the overview clear, Figure 2b no more reference marks are shown in Fig. 6.

[0301] ​For appropriately chosen paths, which can include paths 57a', 57b' and 57c', a first group of first regions can be established, wherein each first group of first regions is connected to each other by means of a respective connected first special region 67a', 67b', 67c', 67d', 67e', 67f' of the shell 53'. The stress values within the first special regions 66a' to 67f' lie within the first interval.

[0302] For appropriately chosen paths, which can include paths 57a', 57b' and 57c', a first group of first regions can be established, wherein each first group of first regions is connected to each other by means of a respective connected first special region 67a', 67b', 67c', 67d', 67e', 67f' of the shell 53'. The stress values within the first special regions 66a' to 67f' lie within the first interval.

[0303] For example, because the first region 63c-1' and the first region 69' are connected to each other by means of the connected first special region 67b', the first region 63c-1' and the first region 69' can be grouped within the same group of the first groups. In contrast thereto, for example, because the first region 63c-2' and the first region 69' are separated by a second special region having a different stress value, they are not connected by any common special region.

[0304] Obviously, there are 6 first special regions and 6 second special regions.

[0305] On the unfolded cylindrical shell 53' (not shown separately), the second special regions are designed in the form of (more than 6) strips parallel to each other. On the unfolded cylindrical shell 53' (not shown separately), the first special regions are designed in the form of (more than 6) strips parallel to each other. The actual number of strips depends on the position at which the cylindrical shell 53' starts to unfold.

[0306] Figure 3 A schematic view of a first exemplary production line for producing a glass tube element, for example the glass tube element 51 or 51', is shown.

[0307] The glass tube line 111 formed by the certain shaping device 113 is redirected into a horizontal direction. The shaping device 113 is not explained in detail here, but it can be designed to perform, for example, a Danner method or a Vello method.

[0308] It is known that the glass tube element is part of the glass tube line 111. Alternatively, it can be said that the glass tube element is connected in one piece to a further glass tube element during its production. Subsequently, the glass tube line 111 is used to manufacture the glass tube element, for example the glass tube element 51 or 51'.

[0309] Therefore, even if reference is made to the glass tube line 111, it is clear to the person skilled in the art that, since the glass tube element corresponds to a respective section of the glass tube line, each treatment undergone by the glass tube line 111 is also applicable to the glass tube element. Vice versa. If it is stated that a glass tube element is treated in a certain way, this is the same as if the glass tube line from which it has been manufactured has been treated in this way (unless otherwise stated or apparent from the context).

[0310] The glass tube line 111 extends in horizontal direction parallel to the x-axis, which corresponds to the defined movement path, starting from a position at x = 0 (see Figure 3 The glass tube line 111 has a defined movement speed, preferably 30 cm / s. The glass tube line 111, and thus the respective sections of the glass tube line 111 corresponding to the glass tube element, passes through the cooling device 115 at the defined movement speed in order to establish a locally varying cooling rate of the glass tube line 111, and thus of the glass tube element. The surface temperature of the glass tube line 111 is temporarily between Tg- 50°C and Tg+ 150°C when passing through the cooling device 115. Tg refers to the transition temperature.

[0311] The cooling device 115 has a plurality of four contact devices 117a to 117d. Each contact device 117a to 117d is designed in the form of a caster. The contact devices 117a to 117d are in direct contact with at least one area of the outer surface of the glass tube line 111, and thus of the respective glass tube element, at least from time to time.

[0312] More precisely, the four contact devices 117a to 117d are in contact with the outer surface of the glass tube element, i.e. of the respective section of the glass tube line 111, one after the other in time. The section of the glass tube line 111 corresponding to the glass tube element, e.g. the glass tube element 51 or 51', is first in contact with the contact device 117a, then with the contact device 117b, then with the contact device 117c and finally with the contact device 117d. Of course, this does not exclude that more than one contact device is in contact with the outer surface at the same time.

[0313] The locally varying cooling rate of the glass tube line 111 is achieved by the contact devices 117a to 117d. All contact devices 117a to 117d have a thermal conductivity of between 1 W / (m x K) and 100 W / (m x K) at least in the area in contact with the glass tube line 111. In fact, the thermal conductivity is preferably between 30 W / (m x K) and 50 W / (m x K). This way the cooling rate can be controlled and varied.

[0314] It has been proven that varying the cooling rate can improve the stress pattern and thus the quality of the glass tube element.

[0315] The contact devices 117a-117d are located in a consecutive manner at spatial positions Pl...P4 along the movement path. Each two contact devices arranged in a consecutive manner, i.e. preferably they are directly adjacent, have a center distance (preferably measured along the movement path) of not more than 50 cm. In fact, the center distance is 50 cm. Further contact devices 119a-119d are provided at spatial positions P5...P8.

[0316] Figure 4 A schematic cross-sectional view of a contact device, e.g. the caster 117a, is shown. The view is obtained through a cutting plane perpendicular to the x-axis in Fig. 2 such that the view comprises the central axis of the contact device.

[0317] The caster 117a (and the same for the casters 117b-117d) has a V-shaped notch which allows supporting and / or moving the glass tubing 111 along the movement path. This shaping allows the contact device, e.g. the caster 117a, to simultaneously contact two regions 121a, 121b of the outer surface of the glass tubing 111 (and thus of the glass tubing element) by means of respective contact areas of the contact device. The contact areas and the regions 121a, 121b of the outer surface contacted by the contact device 117a are separate from each other.

[0318] The regions 121a, 121b are generated by the surface area, i.e. the contact area, of the caster which has at least one point having a distance D / 2 from the central axis of the caster 117a of not more than 10 cm.

[0319] Once the glass tubing 111 (or the segment thereof corresponding to the glass tubing element) leaves the cooling device 115, the glass tubing 111 has a surface temperature lower than Tg-50°C. Of course, this is not mandatory and its surface temperature can still be between Tg-50°C and Tg+150°C. However, in a preferred arrangement, the temperature is lower than Tg-50°C. This is a fact because, in this case, the subsequent contact of the glass tubing 111 with other elements has no or no significant or at least no detrimental effect on any preferred properties of the glass tubing 111 (and thus of the glass tubing element).

[0320] In fact, in the arrangement of Figure 3 In fact, in the arrangement of

[0321] Of course, in other preferred embodiments, the casters 119a-119d can correspond to contact devices of a second cooling device.

[0322] As indicated by the circular arrows in Figure 3 , the glass tubing line 111 is rotated during its cooling at a rotation speed of 1 turn per second or higher. In fact, since the glass tubing line 111 is always rotated throughout the time until the forming, it is also rotated during the cooling.

[0323] Downstream of some of the conveying devices 123, the glass tubing line 111 is formed so as to obtain from the line single glass tubing elements of a desired length, for example the glass tubing elements 51 or 51’.

[0324] Figure 5 A schematic view of a second exemplary production line for producing glass tubing elements, for example the glass tubing elements 51 or 51’, is shown. The structural features of the second exemplary production line which are identical or similar to those of the first exemplary production line are denoted in Figure 5 with the same reference numerals but with a prime.

[0325] It is apparent that the second exemplary production line is largely similar to the first exemplary production line described with reference to Figure 3 . Therefore, here only the differences between the first exemplary production line and the second exemplary production line need to be discussed. Further, reference can be made to the above explanations with respect to Figure 3 .

[0326] Figure 5 The production line of comprises the cooling device 115’ having 5 contact devices 117a’ to 117e’.

[0327] The contact devices 117a’ to 117e’ are located in a consecutive manner at spatial positions P1’... P5’ along the movement path. Each two contact devices arranged in a consecutive manner, i.e. preferably they are directly adjacent, have a center distance (preferably measured along the movement path) of not more than 50 cm. In fact, the center distance is 30 cm.

[0328] This means that one contact device 117e’ is added. And the center distance between the adjacent contact devices 117a’ to 117e’ is reduced from 50 cm to 30 cm.

[0329] This setup allows to increase the interaction between the cooling device 115’ and the glass tubing line 111’ during the cooling.

[0330] It turns out that the increase of the interaction is beneficial, even though it comes with a higher setup cost. Due to the special designed stress pattern, the resulting glass tubing elements have a higher quality.

[0331] The cooling device 115' does not comprise further casters 119a' to 119e' located at the spatial positions P6'... P10'.

[0332] Figure 6 A schematic view of a third exemplary production line for producing a glass tube element, e.g. the glass tube element 51 or 51', is shown. Structural features of the third exemplary production line which are identical or similar to structural features of the first and / or second exemplary production line are denoted in Figure 6 by the same reference numerals but with double quotation marks (").

[0333] It is apparent that the third exemplary production line is largely similar to the first and second exemplary production lines described with reference to Figure 3 and Figure 5 Thus, only the differences between the first, second and third exemplary production lines will be discussed here. Further, reference can be made to the above explanations regarding Figure 3 and Figure 5

[0334] Figure 6 The production line comprises a cooling device 115" having 5 contact devices 117a" to 117e" located at spatial positions P1"... P5" along the movement path in a consecutive manner.

[0335] The plurality of contact devices 117a" to 117e" can be divided into two groups according to the diameter and the center distance.

[0336] The first group comprises the contact devices 117a" to 117d" at the spatial positions P1"... P4" and the second group comprises the contact device 117e" at the spatial position P5". The diameter of the first group of contact devices 117a" to 117d" is smaller than the diameter of the second group of contact devices 117e". The smaller diameter leads to a reduction of the center distance of adjacent contact devices 117a" to 117d" to 3 cm.

[0337] This setup allows for an increased interaction between the cooling device 115" and the glass tube line 111" during cooling. It turned out to be advantageous that the contact devices are closer together. Thus, by reducing the size, in particular the diameter of the contact devices designed as casters, more contact devices can be applied at higher temperatures.

[0338] Since different casters are used in the setup of Figure 6 different interactions are obtained depending on the first contact time and the caster diameter.

[0339] Figure 7 ​A schematic view of a fourth exemplary production line for producing glass tube elements, for example the glass tube elements 51 or 51', is shown. The structural features of the fourth exemplary production line which are identical or similar to the structural features of the first, second and / or third exemplary production line are denoted by the same reference numerals, but with triple quotation marks (""). Figure 7

[0340] It is apparent that the fourth exemplary production line is substantially similar to the first, second and third exemplary production lines described with reference to Figure 3 , Figure 5 and Figure 6 . Here, only the differences between the first, second, third and fourth exemplary production lines will be discussed. In addition, reference can be made to the above explanations regarding Figure 3 , Figure 5 and Figure 6 .

[0341] Figure 7 The production line according to the fourth exemplary embodiment comprises a cooling device 115"' having six contact devices 117a"' to 117f"' located at spatial positions P1"'...P6"' along the movement path in a consecutive manner.

[0342] The plurality of contact devices 117a"' to 117f"' can be divided into two groups according to the diameter and the center distance.

[0343] The first group comprises the contact devices 117b"' to 117d"' at the spatial positions P2"'...P4"' and the second group comprises the contact devices 117a"' and 117f"' at the spatial positions P1"' and P5"'. The diameter of the first group of contact devices 117b"' to 117d"' is smaller than the diameter of the second group of contact devices 117a"' and 117f"'. The smaller diameter results in a reduction of the center distance of the adjacent contact devices 117b"' to 117d"' to 3 cm.

[0344] The arrangement of the contact devices 117a"' to 117f"' is such that the glass tube string 111"' is first contacted with the contact device 117a"' of the second group, then one after the other with the contact devices 117b"' to 117d"' of the first group and finally with the contact device 117e"' of the second group.

[0345] In other words, by means of the contact device 117a"' of large diameter, a first interaction between the glass tube string 111"' and the cooling device 115"' takes place. Then, the interaction takes place by means of the contact devices 117b"' to 117e"' of smaller diameter. Finally, the interaction takes place by means of the contact device 117f"' of large diameter.

[0346] ​This alternating interaction results in a plurality of different types of special areas on the housing of the respective glass tube element. More specifically, due to the different types of interaction, the stress values of the different special areas lie in different value ranges.

[0347] The cooling device 115"' does not comprise further casters 119a"' to 119d"' at the spatial positions P6"'...P10"'.

[0348] Figure 8 A schematic view of a fifth exemplary production line for producing glass tube elements, for example the glass tube elements 51 or 51', is shown. Structural features of the fifth exemplary production line which are identical or similar to structural features of the first, second, third and / or fourth exemplary production line are denoted by the same reference numerals but with four quotation marks (""). Figure 8

[0349] The fifth exemplary production line is based in particular on the fourth exemplary production line described with reference to Figure 7 . Therefore, only the differences between the fourth and the fifth exemplary production line will be discussed here. Otherwise, reference can be made to the above explanations regarding Figure 7 .

[0350] Figure 8 The production line comprises a cooling device 115"' with 7 contact devices 117a'" to 117f'" which are located in a consecutive manner at the spatial positions P1'"...P6'" along the movement path. In fact, 117a'" denotes two contact devices which are both located at P1'" and which form a contact device group. The contact devices 117a'" of this contact device group are arranged rotationally symmetrically around the glass tube line 111, and thus around the glass tube element 51 or 51'.

[0351] In other words, one of the two contact devices 117a'" is located above the level of the glass tube line 111'", and the other one is located below the level of the glass tube line 111'".

[0352] This is merely another design option for increasing the number of interaction elements, in particular contact devices. This makes it possible for four contact surfaces between the cooling device 115'" and the glass tube line 111'" at the spatial position P1'" to interact with one another with little spatial requirement and consumption, each of the two contact devices 117a'" having two contact areas (see the description regarding Figure 4 .

[0353] For the implementation of the present application in its different embodiments, the features disclosed in the description, the drawings and the claims are essential, either alone or in combination.

[0354] ​List of reference signs:

[0355] 1 glass tube element

[0356] 3 housing

[0357] 5 surface

[0358] 7 surface

[0359] 8 tube cavity

[0360] 9 water

[0361] 11a, 11b light rays

[0362] 51 glass tube element

[0363] 53 housing

[0364] 55 tube cavity

[0365] 57a, 57a, 57c path

[0366] 59 surface

[0367] 61a, 61b, 61c region

[0368] 61a-1' region

[0369] 61a-2' region

[0370] 61a-3' region

[0371] 63a, 63b, 63c region

[0372] 63a-1' region

[0373] 63a-2' region

[0374] 63a-3' region

[0375] 65 region

[0376] 65a', 65b', 65c', 65d', 65e', 65f' region

[0377] 67 region

[0378] 67a', 67b', 67c', 67d', 67e', 67f' region

[0379] 111, 111', 111", 111"', 111"" glass tube line

[0380] 113, 113', 113", 113"', 113"" forming device

[0381] 115, 115', 115", 115'", 115"" cooling device

[0382] 117a, 117a', 117a", 117a"', 117a"" contact device

[0383] 117b, 117b', 117b", 117b"', 117b"" contact device

[0384] 117c, 117c', 117c", 117c"', 117c"" contact device

[0385] 117d, 117d', 117d", 117d"', 117d"" contact device

[0386] 117e', 117e", 117e"', 117e"" contact device

[0387] 117f"', 117f"" contact device

[0388] 119a, 119a', 119a", 119a"', 119a"" contact device

[0389] 119b, 119b', 119b", 119b"', 119b"" contact device

[0390] 119c, 119c', 119c", 119c"', 119c"" contact device

[0391] 119d, 119d', 119d", 119d"', 119d"" contact device

[0392] 119e', 119e", 119e"', 119e"" contact device

[0393] 121a, 121b region

[0394] 123, 123', 123", 123"', 123"" transport device

[0395] P1, P1', P1", P1"', P1"" position

[0396] P2, P2', P2", P2"', P2"" position

[0397] P3, P3', P3", P3"', P3"" position

[0398] P4, P4', P4", P4"', P4"" position

[0399] P5, P5', P5", P5"', P5"" position

[0400] P6, P6', P6", P6"', P6"" position

[0401] P7, P7', P7", P7"', P7"" position

[0402] P8, P8', P8", P8"', P8"" position

[0403] P9', P9", P9"', P9"" position

[0404] P10', P10", P10"', P10"" position

[0405] P11"', P11"" position

[0406] D distance

[0407] x, x', x", x"', x"" axis

Claims

1. Glass tube element comprising: at least one section in the form of a hollow cylinder, wherein the section has at least one shell enclosing at least one lumen, characterized in that at least one path extending over a surface of the shell facing away from the lumen can be defined, wherein the path extends through at least one first region of the shell, in which region a stress value lies within a first interval, and at least one second region of the shell, in which region a stress value lies within a second interval.

2. Glass tube element according to claim 1, characterized in that the path follows at least one intersection line over the entire length of the glass tube element or a section thereof, which intersection line can be obtained by the intersection of a plane comprising the entire central axis of the glass tube element with the surface of the shell facing away from the lumen.

3. The glass tube element according to claim 1, characterized in that the path follows at least one intersection line over the entire circumference of the glass tube element or the at least one section thereof, which intersection line can be obtained by the intersection of a plane perpendicular to the central axis of the glass tube element with the surface of the shell facing away from the lumen.

4. Glass tube element according to any one of claims 1 to 3, characterized in that in at least one direction along the path, the second region follows directly after the first region.

5. Glass tube element according to any one of claims 1 to 3, characterized in that the path extends through a first number of first regions and a second number of second regions.

6. Glass tube element according to claim 5, characterized in that first and second regions are repeatedly alternatingly present in at least one direction along the path.

7. Glass tube element according to claim 6, characterized in that first and second regions are repeatedly alternatingly directly consecutively present in at least one direction along the path.

8. The glass tubing element according to claim 5, characterized in that the first number comprises the same number of regions as the second number.

9. Glass tube element according to any one of claims 1 to 3, characterized in that in at least one direction along the path, the path extends through the at least one first region of the shell and at least one third region of the shell, in which third region a stress value lies within a third interval.

10. Glass tube element according to claim 9, characterized in that in this direction along the path, the third region (1) follows directly after the first region and / or (2) is arranged between the first region and the next first or second region downstream of the path.

11. The glass tubing element according to claim 9, characterized in that in this direction along the path, the third region (1) follows directly after the first region and / or (2) is arranged directly between the first region and the next first or second region downstream of the path.

12. Glass tube element according to any one of claims 1 to 3, characterized in that in at least one direction along the path, within at least one second region, the path extends through a plurality of consecutive sub-regions of the second region, wherein the stress value of each sub-region lies within a respective sub-interval comprised by the second interval.

13. The glass tubing element according to any one of claims 1 to 3, characterized in that in at least one direction along the path, within all second regions, the path extends through a plurality of consecutive sub-regions of the second region, wherein the stress value of each sub-region lies within a respective sub-interval comprised by the second interval.

14. The glass tubing element of claim 12, wherein, the value ranges of the individual sub-intervals differ at least partially, are at least partially identical, at least partially overlap and / or at least partially do not overlap.

15. Glass tube element according to claim 9, characterized in that the different regions are arranged along the path such that at least one of the second regions and / or the third regions is arranged diametrically opposite at least one first region.

16. The glass tubing element of claim 9, wherein, the different regions are arranged along the path such that each of the second regions and / or the third regions is arranged diametrically opposite each first region.

17. The glass tubing element according to any one of claims 1 to 3, characterized in that the value range of the first interval differs and / or does not overlap with the value range of the second interval.

18. Glass tube element according to any one of claims 1 to 3, characterized in that the value of the first interval corresponds to a compressive stress, the upper boundary of the second interval has an absolute value which is greater than the maximum absolute value of the first interval.

19. The glass tubing element according to claim 18, characterized in that the first interval comprises a value range between -0.5 MPa and -10 MPa.

20. The glass tubing element of claim 18, wherein, the first interval comprises a value range between -1 MPa and -8 MPa.

21. The glass tubing element of claim 18, wherein, the first interval comprises a value range between -1 MPa and -5 MPa.

22. The glass tubing element of claim 18, wherein, the first interval comprises a value range between -4 MPa and -6 MPa.

23. The glass tubing element of claim 18, wherein, the first interval comprises a value range between -3 MPa and -8 MPa.

24. The glass tubing element of claim 18, wherein, the second interval corresponds to a shift of up to -5 MPa relative to the first interval.

25. The glass tubing element of claim 18, wherein, the second interval corresponds to a shift of between -0.5 MPa and -3 MPa relative to the first interval.

26. The glass tubing element of claim 18, wherein, the second interval corresponds to a shift of between -1 MPa and -2.5 MPa relative to the first interval.

27. Glass tube element according to any one of claims 1 to 3, characterized in that the segments of the path located within the first regions and / or the second regions respectively have the same length.

28. The glass tubing element of claim 12, wherein, the segments of the path located within the sub-regions of the second regions respectively have the same length.

29. Glass tube element according to claim 12, characterized in that the segments of the path located within the sub-regions of at least one second region respectively have a length defined for all sub-regions, the sub-regions having respective sub-ranges.

30. The glass tubing element of claim 29, wherein, the segments of the path located within the sub-regions of all second regions respectively have a length defined for all sub-regions, the sub-regions having respective sub-ranges.

31. Glass tube element according to claim 9, characterized in that the first regions, the second regions and / or the third regions respectively comprise (1) at least one surface region of the shell facing away from the surface of the lumen and / or (2) at least one volume region of the shell.

32. The glass tubing element of claim 12, wherein, the sub-regions comprise (1) at least one surface region of the shell facing away from the surface of the lumen and / or (2) at least one volume region of the shell.

33. The glass tubing element of claim 31, wherein, the shell has a thickness measured in a perpendicular direction from a surface of the shell facing away from the lumen.

34. Glass tube element according to any one of claims 1 to 3, characterized in that for a plurality of parallel extending paths of the defined kind, a first group of first regions can be defined, wherein each of the first regions of the first group are connected to each other by means of connected first characteristic regions of the shell, a second group of second regions can be defined, wherein each of the second regions of the second group are connected to each other by means of connected second characteristic regions of the shell, and / or a third group of third regions can be defined, wherein each of the third regions of the third group are connected to each other by means of connected third characteristic regions of the shell.

35. The glass tubing element of claim 34, wherein, for a plurality of parallel extending paths of a defined kind, a subgroup of subregions of the second regions can be defined, wherein each of the subregions of the subgroup are connected to each other by means of connected characteristic subregions of the shell.

36. The glass tubing element of claim 34, wherein, a stress value within the first characteristic regions lies within the first interval, a stress value within the second characteristic regions lies within the second interval, and / or a stress value within the third characteristic regions lies within a third interval.

37. The glass tubing element of claim 35, wherein, a stress value within the characteristic subregions lies within the subinterval corresponding to the respective subregion.

38. The glass tube element according to claim 34, characterized in that on the unrolled cylindrical shell, the first characteristic regions, the second characteristic regions, and / or third characteristic regions are designed in the form of at least one strip, respectively, at least partially.

39. The glass tubing element of claim 35, wherein, on the unrolled cylindrical shell, the characteristic subregions and / or the respective outer surface, i.e. the aforementioned surface facing away from the lumen, are designed in the form of at least one strip, respectively, at least partially.

40. The glass tubing element of claim 34, wherein, on the unrolled cylindrical shell, the first characteristic regions, the second characteristic regions, and / or third characteristic regions are designed in the form of a plurality of parallel and / or non-parallel strips, respectively.

41. The glass tubing element of claim 35, wherein, on the unrolled cylindrical shell, the characteristic subregions and / or the respective outer surface, i.e. the aforementioned surface facing away from the lumen, are designed in the form of a plurality of parallel and / or non-parallel strips, respectively.

42. The glass tube element according to claim 34, characterized in that the number of first characteristic regions, the number of second characteristic regions, and / or the number of third characteristic regions of the shell is between 1 and 100, respectively.

43. The glass tubing element of claim 42, wherein, the number of first characteristic regions, the number of second characteristic regions, and / or the number of third characteristic regions of the shell is between 2 and 50, respectively.

44. The glass tubing element of claim 42, wherein, the number of first characteristic regions, the number of second characteristic regions, and / or the number of third characteristic regions of the shell is between 2 and 30, respectively.

45. The glass tubing element of claim 42, wherein, the number of first characteristic regions, the number of second characteristic regions, and / or the number of third characteristic regions of the shell is between 5 and 20, respectively.

46. The glass tubing element of claim 35, wherein, the number of characteristic subregions is between 1 and 100.

47. The glass tubing element of claim 46, wherein, the number of characteristic subregions is between 2 and 50.

48. The glass tubing element of claim 46, wherein, the number of characteristic subregions is between 2 and 30.

49. The glass tubing element of claim 46, wherein, the number of characteristic subregions is between 5 and 20.

50. The glass tube element according to any one of claims 2 to 3, wherein the optical retardation values of the light rays obtained by the different measurements each fall within a range between 3 nm and 30 nm when the glass tube element is optically measured by means of at least one light ray extending along a measurement path extending in a measurement direction perpendicular to a main extension direction of the glass tube element and tangential to the surface of the housing facing away from the lumen and contacting the surface for different measurements at different positions each having a different azimuthal angle in a cylindrical coordinate system fixedly attached to the glass tube element and having its origin on the central axis of the glass tube element, wherein (1) the light rays comprise a wavelength between 250 nm and 900 nm; (2) the glass tube element is surrounded by at least one fluid such that at least the surface of the housing facing away from the lumen is in contact with the fluid; (3) the glass tube element is completely immersed in at least one fluid such that at least the surface of the housing facing away from the lumen and the surface of the housing facing towards the lumen are in contact with the fluid; (4) the fluid has an optical density for the wavelength of the light rays which differs at most by 1% from the optical density of the glass material of the glass tube element; (5) the fluid has an optical density for the wavelength of the light rays between 1.2 and 2.5; (6) the fluid comprises ethanol, olive oil, carbon tetrachloride, sunflower oil, turpentine, glycerol, furfuryl alcohol, dibutyl phthalate 84-74-2, toluene, benzene, dimethyl phthalate, monochlorobenzene or silicone oil or any combination thereof; (7) the optical retardation of the light rays obtained by the different measurements has values each falling between 10 nm and 150 nm and / or the optical retardation of the light rays obtained by the different measurements has values each falling between 3 nm and 30 nm; (8) the measurements are performed for different azimuthal angles selected from integer values between 0 degrees and 359 degrees and including 0 and 359 degrees for 360 measurements; (9) the different regions are arranged along the path such that the optical retardation values lie within the magnitude of the range; and / or (10) the measurements are performed for positions having the same height and / or the same radius within the cylindrical coordinate system.

51. The glass tubing element of claim 50, wherein, the light rays comprise a wavelength between 390 nm and 800 nm.

52. The glass tubing element of claim 50, wherein, the light rays comprise a wavelength of 394 nm or 633 nm.

53. The glass tubing element of claim 50, wherein, the fluid has an optical density for the wavelength of the light rays between 1.3 and 1.

7.

54. The glass tubing element of claim 50, wherein, the fluid has an optical density for the wavelength of the light rays of 1.362, 1.460, 1.463, 1.472, 1.473, 1.474, 1.486, between 1.492 and 1.493, 1.497, 1.501, 1.516, 1.525 or between 1.43 and 1.

61.

55. The glass tubing element of claim 50, wherein, the optical retardation of the light rays obtained by the different measurements has values each falling between 20 nm and 100 nm.

56. The glass tubing element of claim 50, wherein, the optical retardation of the light rays obtained by the different measurements has values each falling between 4 nm and 25 nm.

57. The glass tubing element of claim 50, wherein, The optical retardation of the light rays obtained by the different measurements has values all falling between 5 nm and 20 nm. The optical retardation of the light rays obtained by the different measurements has values all falling between 5 nm and 20 nm.

Images