Glass tube element with improved quality

Abstract

A glass tube element having hollow cylindrical section that has a shell enclosing a lumen and extends along a main extension and an optical delay of a light ray. The shell has a surface facing away from the lumen. The optical delay has values that all fall within a range having a size of between 3 and 30 nm. The optical delay being an optical measurement of the glass tube element by the light ray extending along a measurement path in a direction of perpendicular to the main extension and tangent to a surface of the shell. The measurement path touches the surface for different measurements at different positions each having a different azimuth angle within a cylindrical coordinate system fixedly attached to the glass tube element and having an origin on a center axis of the glass tube element.

Claims

1. A glass tube element, comprising: hollow cylindrical section that has a shell enclosing a lumen and extends along a main extension, the shell having a surface facing away from the lumen; and an optical delay of a light ray, the optical delay having values that all fall within a range having a size of between 3 and 30 nm, the optical delay being an optical measurement of the glass tube element by the light ray extending along a measurement path in a direction perpendicular to the main extension and tangent to a surface of the shell, the measurement path touches the surface for different measurements at different positions each having a different azimuth angle within a cylindrical coordinate system fixedly attached to the glass tube element and having an origin on a center axis of the glass tube element.

2. The glass tube element of claim 1, wherein the light ray has a wavelength of between 250 and 900 nm.

3. The glass tube element of claim 1, wherein the light ray has a wavelength of between 394 nm or 633 nm.

4. The glass tube element of claim 1, wherein the glass tube element is completely immersed in a fluid such that the surface and a second surface of the shell facing towards the lumen, both, are in contact with the fluid.

5. The glass tube element of claim 1, further comprising a fluid in contact with the surface.

6. The glass tube element of claim 5, wherein the fluid has an optical density that is at most 1% different compared to an optical density of glass material of the glass tube element.

7. The glass tube element of claim 5, wherein the fluid has an optical density of between 1.2 and 2.5.

8. The glass tube element of claim 5, wherein the fluid has an optical density of between 1.3 and 1.7.

9. The glass tube element of claim 5, wherein the fluid has an optical density of between 1.43 and 1.61.

10. The glass tube element of claim 5, wherein the fluid is selected from a group consisting of: ethyl alcohol, olive oil, carbon tetrachloride, sunflower oil, terpentine, glycerine, furfuryl alcohol, dibutylphtalat 84-74-2, toluol, benzene, dimethyphtalate, monochlorobenzene, silicon oil, and any combinations thereof.

11. The glass tube element of claim 1, wherein the optical delay has values which all fall within a range of between 10 and 150 nm.

12. The glass tube element of claim 1, wherein the optical delay has values which all fall within a range of between 20 and 100 nm.

13. The glass tube element of claim 1, wherein the optical delay has values which all fall within a range having a size of between 4 and 25 nm.

14. The glass tube element of claim 1, wherein the optical delay has values which all fall within a range having a size of between 5 and 20 nm.

15. The glass tube element of claim 1, wherein the optical measurement comprises 360 measurements with the different azimuth angle ranging between, and inclusive of, zero and 359 degrees.

16. The glass tube element of claim 1, wherein the optical measurement comprises measurements carried out for positions having a same height and/or a same radius within the cylindrical coordinate system.

17. The glass tube element of claim 1, wherein the glass tube element has a length of between 0.5 and 5 m.

18. The glass tube element of claim 1, wherein the glass tube element has a maximal outer diameter between 1 and 100 mm.

19. The glass tube element of claim 1, wherein the shell has an average thickness of between 0.1 and 5 mm.

20. The glass tube element of claim 1, wherein the glass tube element comprises glass selected from a group consisting of silicate glass, soda lime glass, alumosilicate glass, borosilicate glass, and any combinations thereof.

21. The glass tube element of claim 1, wherein the glass tube element comprises glass having a transition temperature that is higher than 300 degrees C. and/or lower than 900 degrees C.

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) Various aspects of this invention will become apparent to those skilled in the art from the following detailed description of preferred embodiments, when read in light of the accompanying schematic drawings, wherein:

(2) FIG. 1a shows an illustration of a cross-sectional plane of a glass tube element according to the invention.

(3) FIG. 1b shows a plot of the optical delay (in nanometers) over the azimuth angle (in degrees) for the glass tube element of FIG. 1a.

(4) FIG. 1c shows an illustration of a plot representing the relative course of the optical delay obtained for the glass tube element.

(5) FIG. 2 shows a glass tube element according to the invention.

(6) FIG. 3 shows a schematic illustration of a first exemplary production line.

(7) FIG. 4 shows a schematic cross-sectional view of a contacting device.

(8) FIG. 5 shows a schematic illustration of a second exemplary production line.

(9) FIG. 6 shows a schematic illustration of a third exemplary production line.

(10) FIG. 7 shows a schematic illustration of a fourth exemplary production line.

(11) FIG. 8 shows a schematic illustration of a fifth exemplary production line.

DETAILED DESCRIPTION

(12) FIG. 2 shows a glass tube element 101 according to the invention.

(13) It has a hollow cylindrical form (not only a section thereof, but entirely) and a shell 103 which encloses a lumen 105. The length (this is, from top to bottom) of the glass tube element 101 is 1.5 m. The nominal outer diameter of the glass tube element 101 is 24 mm. The shell 103 has an average thickness T of 1 mm. The glass tube element 101 extends along a direction R.

(14) When conducting optical measurements on the glass tube element 101 by means of at least one light ray which extends along a measurement path, which measurement path extends in a direction of measurement perpendicular to the direction of the main extension of the glass tube element 101 and which measurement path is tangent to the surface of the shell 103 facing away from the lumen 105, namely the outer surface of the shell 103, and which measurement path touches the surface for different measurements at different positions each having a different azimuth angle within a cylindrical coordinate system fixedly attached to the glass tube element 101 and having its origin on the center axis of the glass tube element 101, the optical delays of the light ray obtained from the different measurements have values which all fall within a range having a size of between 3 and 30 nm.

(15) FIG. 3 shows a schematic illustration of a first exemplary production line for producing a glass tube element such as the glass tube element 51 or 51′.

(16) A glass tube line 111 formed by some forming device 113 is redirected into a horizontal direction. The forming device 113 is not specified in more detail here, but it may be designed for conducting for example a Danner process or a Vello process.

(17) It is acknowledged that the glass tube element is part of the glass tube line 111. Alternatively it might be stated that the glass tube element during its production process is connected to further glass tube elements in one piece. From the glass tube line 111 subsequently glass tube elements, such as the glass tube element 101, are confectioned.

(18) Therefore, even if reference is made to the glass tube line 111, the person skilled in the art clearly understands that every treatment the glass tube line 111 undergoes is also applied to the glass tube elements because these elements correspond to respective sections of the glass tube line 111. Vice versa the same is true: If it is stated that a glass tube element is treated somehow, this is the same as if the glass tube line, from which the glass tube element has been confectioned, is treated that way (unless otherwise stated or evident from the context).

(19) Starting from a Position of x=0 (see FIG. 3) the glass tube line 111 runs in a horizontal direction parallel to the x axis corresponding to a defined path of movement. The glass tube line 111 has a defined speed of movement, preferably of 30 cm/s. The glass tube line 111, hence the glass tube element corresponding to the respective section of the glass tube line 111, passes with the defined speed of movement through a cooling device 115, for setting up a locally modified cooling rate of the glass tube line 111 (hence the glass tube elements). The glass tube line 111 has at least temporarily a surface temperature of between Tg−50 and Tg+150 degrees C. while passing through the cooling device 115. Tg means the transition temperature.

(20) The cooling device 115 has a plurality of four contacting devices 117a-117d. Each contacting device 117a-117d is designed in form of a castor. The contacting devices 117a-117d has at least from time to time direct contact with at least one area of the outer surface of the glass tube line 111 (hence the corresponding glass tube elements).

(21) To be more precise, the four contacting devices 117a-117d comes in contact with the outer surface of the glass tube element (i.e., the respective section of the glass tube line 111) one after another in time. A section of the class tube line 111 corresponding to a glass tube element such as the glass tube element 51 or 51′ first comes in contact with contacting device 117a, then with contacting device 117b, then with contacting device 117c, and finally with contacting device 117d. Of course, this does not exclude that more than one contacting device has contact at the same time with the outer surface.

(22) The locally modified cooling rate of the glass tube line 111 is achieved by means of the contacting devices 117a-117d. The contacting devices 117a-117d all have, at least in the area where the glass tube line 111 is contacted, a thermal conductivity of between 1 and 100 W/(m*K). Indeed, it is preferably between 30 and 50 W/(m*K). This allows to manipulate and change the cooling rate.

(23) Changing the cooling rate has been proven to lead to increased homogeneity of the optical delay, hence to improved quality of the glass tube element.

(24) The contacting devices 117a-117d are located at spatial positions P1 . . . P4 down along the path of movement in a consecutive manner. Each of two contacting devices arranged in a consecutive manner (i.e., preferably they are direct neighbors) have a center-center-distance, preferably measured along the path of movement, of 50 cm or less. Indeed, the center-center-distance is 50 cm. Further contacting devices 119a-119d are provided at spatial positions P5 . . . P8.

(25) FIG. 4 shows a schematic cross-sectional view of a contacting device, such as castor, for example castor 117a. The view is obtained by a cutting plane perpendicular to the x axis in FIG. 2 such that the view comprises the center axis of the contacting device.

(26) The castor 117a (and likewise castors 117b-117d) have a V-like recess, which allows to support and/or move the glass tube line 111 along the path of movement. This shaping allows that the contacting device, such as the castor 117a, has at the same time contact with two areas 121a, 121b of the outer surface of the class tube line 111 (hence the class tube elements) by respective contacting areas of the contacting device. The contacting areas and the areas of the outer surface 121a, 121b contacted by the contacting device 117a are separated from each other.

(27) The areas 121a, 121b are produced by surface areas of the castors, i.e., the contacting areas, which have at least one point which in turn has a distance D/2 of 10 cm or less from the center axis of the castor 117a.

(28) Once the glass tube line 111 (or a section thereof corresponding to a glass tube element) exits the cooling device 115, the glass tube line 111 has a surface temperature of less than Tg−50 degrees C. Of course, this is not necessary and it may still has a surface temperature of between Tg−50 and Tg+150 degrees C. However, in the preferred setup the temperature is below Tg−50 degrees C. This is true because in this case, subsequent contacts of the glass tube line 111 with other elements have no or no significant or at least no adverse effect on any preferred properties of the glass tube line 111 (hence, the glass tube elements).

(29) Indeed, in the setup of FIG. 3, following the cooling device 115, the glass tube line 111 get in contact with the further castors 119a-119d provided at spatial positions P5 . . . P8 down along the path of movement in a consecutive manner. However, they might be different from the castors 117a-117d comprised by the cooling device 115 because they are not part of the cooling device 115 and are not used for manipulating the cooling characteristics of the glass tube line 111.

(30) Of course, in other preferred embodiments the castors 119a-119d might correspond to contacting devises of a second cooling device.

(31) As indicated by the circular arrow in FIG. 3, the glass tube line 111 is rotated during its period of cooling with a rotation speed of 1 round or more per second. Indeed, the glass tube line 111 is rotated the entire time until confectioning, hence, also during the period of cooling.

(32) Downstream of some transport device 123, the glass tube line 111 is confectioned so that individual glass tube elements, such as the glass tube element 101, are obtained from that line with a desired length.

(33) FIG. 5 shows a schematic illustration of a second exemplary production line for producing a glass tube element such as the glass tube element 101. Structural features of the second exemplary production line which are identical or similar to the structural features of the first exemplary production line are labeled in FIG. 5 with the same reference numerals, but with a single dash.

(34) It is apparent that the second exemplary production line is largely similar to the first exemplary production line described with respect to FIG. 3. Therefore, only differences between the first and second exemplary production line need to be discussed here. In addition, reference can be made to the above explanations with respect to FIG. 3.

(35) The production line of FIG. 5 comprises a cooling device 115′ which has a plurality of five contacting devices 117a′-117e′.

(36) The contacting devices 117a′-117e′ are located at spatial positions P1′ . . . P5′ down along the path of movement in a consecutive manner. Each of two contacting devices arranged in a consecutive manner (i.e., preferably they are direct neighbors) have a center-center-distance, preferably measured along the path of movement, of 50 cm or less. Indeed, the center-center-distance is 30 cm.

(37) This means, there has been added one contacting device 117e′. And the center-center-distance between adjacent contacting devices 117a′-117e′ has been reduced from 50 cm to 30 cm.

(38) This setup allows an increased interaction between the cooling device 115′ and the glass tube line 111′ during the period of cooling.

(39) It has been proven to be advantageous to apply such an increased interaction, even if it comes on cost of a larger setup. The resulting glass tube elements have improved quality of the glass tube element due to the stress distribution which lead to a homogeneous optical delay.

(40) The further castors 119a′-119e′ at spatial positions P6′ . . . P10′ are not comprised by the cooling device 115′.

(41) FIG. 6 shows a schematic illustration of a third exemplary production line for producing a glass tube element such as the glass tube element 101. Structural features of the third exemplary production line which are identical or similar to the structural features of the first and/or second exemplary production line are labeled in FIG. 6 with the same reference numerals, but with a double dash.

(42) It is apparent that the third exemplary production line is largely similar to the first and second exemplary production line described with respect to FIG. 3 and FIG. 5. Therefore, only differences between the first, second and third exemplary production line need to be discussed here. In addition, reference can be made to the above explanations with respect to FIG. 3 and FIG. 5.

(43) The production line of FIG. 6 comprises a cooling device 115″ which has a plurality of five contacting devices 117a″-117e″ located at spatial position P1″ . . . P5″ down along the path of movement in a consecutive manner.

(44) The plurality of contacting devices 117a″-117e″ can be grouped into two groups with respect to the aspects diameter and center-center-distance.

(45) The first group comprises contacting devices 117a″-117d″ at spatial positions P1″ . . . P4″ and the second group comprises contacting device 117e″ at spatial position P5″. The contacting devices 117a″-117d″ of the first group have a smaller diameter than the contacting device 117e′ of the second group. The smaller diameter allows that the center-center-distance of adjacent contacting devices 117a″-117d″ is reduced to 3 cm.

(46) This setup allows an increased interaction between the cooling device 115″ and the glass tube line 111″ during the period of cooling. It has been proven to be advantageous to have contacting devices which are closer together. Hence, by reducing the size, especially the diameter of a contacting device which is designed as a castor, more contacting devices can be applied during higher temperatures.

(47) Since in the setup of FIG. 6 different castors are used, different interactions are obtained based inter alia on: Time of first contact and castor diameter.

(48) FIG. 7 shows a schematic illustration of a fourth exemplary production line for producing a glass tube element such as the glass tube element 101. 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 labeled in FIG. 7 with the same reference numerals, but with a triple dash.

(49) It is apparent that the fourth exemplary production line is largely similar to the first, second and third exemplary production line described with respect to FIG. 3, FIG. 5 and FIG. 6. Therefore, only differences between the first, second, third and fourth exemplary production line need to be discussed here. In addition, reference can be made to the above explanations with respect to FIG. 3, FIG. 5 and FIG. 6.

(50) The production line of FIG. 7 comprises a cooling device 115′″ which has a plurality of six contacting devices 117a′″-117f′″ located at spatial positions P1′″ . . . P6′″ down along the path of movement in a consecutive manner.

(51) The plurality of contacting devices 117a′″-117f′″ can be grouped into two groups with respect to the aspects diameter and center-center-distance.

(52) The first group comprises contacting devices 117b′″-117d′″ at spatial positions P2′″ . . . P4′″ and the second group comprises contacting devices 117a′″ and 117f′″ at spatial position P1′″ and P5′″. The contacting devices 117b′″-117d′″ of the first group have a smaller diameter than the contacting devices 117a′″ and 117f′″ of the second group. The smaller diameter allows that the center-center-distance of adjacent contacting devices 117b′″-117d′″ is reduced to 3 cm.

(53) The arrangement of the contacting devices 117a′″-117f′″ is such that the class tube line 111′″ comes in contact first with the contacting device 117a′″ of the second group than one after the other of contacting devices 117b′″-117d′″ of the first group and finally with contacting device 117e′″ of the second group.

(54) In other words, the first interaction between the class tube line 111′″ and the cooling device 115′″ is by means of the contacting device 117a′″ which has a large diameter. Then the interaction takes place by means of the contacting devices 117b′″-117e′″ which have smaller diameters. Finally interaction takes place with the contacting device 117f′″ having a larger diameter.

(55) The further castors 119a′″-119d′″ at spatial positions P6′ . . . P10′ are not comprised by the cooling device 115′″.

(56) FIG. 8 shows a schematic illustration of a fifth exemplary production line for producing a glass tube element such as the glass tube element 101. Structural features of the fifth exemplary production line which are identical or similar to the structural features of the first, second, third and/or fourth exemplary production line are labeled in FIG. 8 with the same reference numerals, but with a fourth-times dash.

(57) The fifth exemplary production line is based particularly on the fourth exemplary production line described with respect to FIG. 7. Therefore, only differences between the fourth and fifth exemplary production line need to be discussed here. In addition, reference can be made to the above explanations with respect to FIG. 7.

(58) The production line of FIG. 8 comprises a cooling device 115″″ which in turn has a plurality of seven contacting devices 117a″″-117f″″ located at spatial positions P1′″ . . . P6′″ down along the path of movement in a consecutive manner. Indeed, with 117a″″ two contacting devices located both at P1″″ are denoted which form a contacting device group. The contacting devices 117a″″ of the contacting device group are arranged in a rotationally symmetrical manner around the glass tube line 111 (hence, around glass tube element 101).

(59) In other words, one of the two contacting devices 117a″″ are located horizontal above and the other horizontal below the glass tube line 111″″.

(60) This is just a further design option for increasing the number of interaction elements, especially contacting devices. This allows that at spatial position P1″″ four contacting surfaces interact between the cooling device 115″″ and the glass tube line 111″″ with only little space requirements and consumption: Two contacting devices 117a″″ each having two contacting areas (see description with respect to FIG. 4).

(61) The features disclosed in the description, the figures as well as the claims could be essential alone or in every combination for the realization of the invention in its different embodiments.

LIST OF REFERENCE NUMERALS

(62) 1 Glass tube element 3 Shell 5 Surface 7 Surface 8 Lumen 9 Water 11a, 11b Light ray 101 Glass tube element 103 Shell 105 Lumen 111, 111′, 111″, 111′″, 111″″ Glass tube line 113, 113′, 113″, 113′″, 113″″ Forming device 115, 115′, 115″, 115′″, 115″″ Cooling device 117a, 117a′, 117a″, 117a′″, 117a″″ Contact Device 117b, 117b′, 117b″, 117b′″, 117b″″ Contact Device 117c, 117c′, 117c″, 117c′″, 117c″″ Contact Device 117d, 117d′, 117d″, 117d′″, 117d″″ Contact Device 117e′, 117e″, 117e′″, 117e″″ Contact Device 117f′″, 117f′″ Contact Device 119a, 119a′, 119a″, 119a′″, 119a″″ Contact Device 119b, 119b′, 119b″, 119b′″, 119b″″ Contact Device 119c, 119c′, 119c″, 119c′″, 119c″″ Contact Device 119d, 119d′, 119d″, 119d′″, 119d″″ Contact Device 119e′, 119e″, 119e′″, 119e″″ Contact Device 121a, 121b Area 123, 123′, 123″, 123′″, 123″″ Transport Device P1, P1′, P1″, P1′″, P1″″ Position P2, P2′, P2″, P2′″, P2″″ Position P3, P3′, P3″, P3′″, P3″″ Position P4, P4′, P4″, P4′″, P4″″ Position P5, P5′, P5″, P5′″, P5″″ Position P6, P6′, P6″, P6′″, P6″″ Position P7, P7′, P7″, P7′″, P7″″ Position P8, P8′, P8″, P8′″, P8″″ Position P9′, P9″, P9′″, P9″″ Position P10′, P10″, P10′″, P10″″ Position P11′″, P11″″ Position D Distance R Direction T Thickness x, x′, x″, x′″, x″″ Axis