Glass rod, set of glass rods and method of manufacturing glass rod

Abstract

To provide a glass rod for manufacturing a flash lamp in completely automated robot-controlled processes.SOLUTION: The present invention relates to a glass rod which has a length lrod, a means half-major-axial length lmajor(a), and a mean half-minor-axial length lminor(a), where: the length lrod is 100 to 1600 mm; lmajor(n) is a distance from a mass center of a cross section in a cross section of the glass rod, to a farthermost border of the glass rod in the cross section; lminor(n) is a distance from the mass center of the cross section to a nearest border of the glass rod in the cross section; and the lmajor(n) and lminor(n) can be equal or different. The glass rod also includes a glass composition which has a T4 temperature of 1400°C or higher defined as a temperature at which glass has a viscosity of 104 dPa s.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a glass rod, a set of glass rods and a method for producing the same.Furthermore, the present invention relates to a flash lamp comprising said glass rod and to the use of a glass rod according to the invention for bonding a metal article to a glass member and / or for a flash lamp. [Background technology]

[0002] Flashlamps have a variety of uses in medical, industrial and scientific applications.

[0003] Flash lamps are typically made from a fused silica / quartz or borosilicate tube, designed as a U-shape, with metal electrodes integrated at its two ends. High voltage power is supplied through a conductive support, which also serves as a mounting or lamp holder during operation. Special glasses have been developed to connect the metallic conductive support of the metal electrodes to the flash lamp tube wall.

[0004] Methods of manufacturing flashlamps known in the art require technical oversight and human control due to process irregularities during flashlamp manufacturing.

[0005] Robotic methods for manufacturing flash lamps are required, but to ensure a continuous and stable workflow, they rely on glass rods that are suitable for fully automated manufacturing processes. Summary of the Invention [Problem to be solved by the invention]

[0006] Thus, there remains a need to provide a glass rod for manufacturing flash lamps in a fully automated, robotically controlled process. Additionally, there is a related desire to provide a method for manufacturing a glass rod that meets the above-mentioned needs and that can be used for manufacturing flash lamps in a robotically controlled process. [Means for solving the problem]

[0007] Summary of the Invention In a first aspect, the present invention provides a method for manufacturing a gyro having a length l rod , average half-major axis length l major(a) , and the average semi-minor axis length l minor(a) A glass rod having a length l rod is 100 to 1600 mm, Within the cross section of the glass rod, l major(n) is the distance from the center of mass of the cross section to the farthest boundary of the glass rod within the cross section, and l minor(n) is the distance from the center of mass of the cross section to the nearest boundary of the glass rod within the cross section, and l major(n) and minor(n) can be the same or different from The glass rod is 10 4 The glass composition has a T4 temperature of 1400°C or more, which is defined as the temperature at which the glass composition has a viscosity of 100 dPa·s, Overall relative length variation of the semimajor axis (tlv major ), relative local area variation (lav), and tlv major +lav, tlv major is determined as the absolute difference between (a) the shortest semi-major axis length of 50 equidistant cross-sectional locations and (b) the longest semi-major axis length of said 50 equidistant cross-sectional locations, and the average value l of the semi-major axis lengths of said 50 equidistant cross-sectional locations major(a) is normalized by The 50 equidistant sections are arranged along the length l of the glass rod. rod The initial position is 0.01×l. rodStarting at position l, and adding an additional increment of 0.02 x l for each successive position rod is used, lav is determined as (c) the absolute difference between the cross-sectional area at the cross-sectional location having the longest semi-major axis length of the 50 equidistant cross-sectional locations and (d) the average of the cross-sectional areas of the 50 equidistant cross-sectional locations, normalized by the average of the cross-sectional areas of the 50 equidistant cross-sectional locations; the quality index is 0.090 or less, 0.070 or less, or 0.050 or less; Regarding the glass rod.

[0008] The glass rod according to the present invention is made of 10 4 The glass compositions include those having a T4 temperature of 1400°C or higher, defined as the temperature at which the glass has a viscosity of 100 dPa·s, and are therefore suitable for the manufacture of flash lamps which undergo high temperatures and numerous extreme temperature changes during their life cycle.

[0009] Glass rods known in the art often exhibit non-uniform shapes, which are believed to result from, among other influences, the small batches of glass (raw) material used for production, the short residence times in the non-continuous process, and the high melting temperatures of the glass compositions used. The observed non-uniform shapes are due to non-uniformities in the glass melt during production, which also appear in the final glass rod product. Non-uniformities in the glass melt also cause, and are directly related to, non-uniformities in the viscosity of the glass melt. Too large deviations from the "perfect shape" cause problems in the subsequent manufacturing process, including robotic handling.

[0010] Of course, the mathematically perfect cylindrical shape of industrially produced glass rods may remain difficult to obtain. The present invention provides glass rods that meet the desires and requirements for homogeneity. Homogeneity is defined as the total relative length variation of the semi-major axis (tlv major The quality index can be evaluated and differentiated through the quality index defined as the sum of the relative local area variation (lav) and the relative local area variation (tlv). majorBoth parameters, λ and lav, reflect the fidelity of the shape of the glass rod.

[0011] The glass rod according to the present invention has a length l rod The glass rod is particularly homogeneous with respect to the overall relative length variation of its semi-major axis, as measured at 50 equidistant cross-sectional locations disposed along the length of the rod, and has a very constant mass throughout its length, as represented by only very small area variations in the 50 equidistant cross-sectional locations measured.

[0012] Overall relative length variation of the semimajor axis (tlv major ) is evaluated with respect to the maximum and minimum values, i.e. the difference, of the 50 equidistant cross-sections, which is then divided by the average value of the semi-major axis length of the 50 equidistant cross-section locations. At the (cross-sectional) location of the longest semi-major axis, the relative local area variation (lav) is determined as the absolute difference between (c) the cross-sectional area at the cross-sectional location having the longest semi-major axis length of said 50 equidistant cross-sectional locations and (d) the average value of the cross-sectional areas of said 50 equidistant cross-sectional locations, normalized by the average value of the cross-sectional areas of the 50 equidistant cross-sectional locations.

[0013] The inventors have established that a quality index of 0.090 or less meets the required standards for glass rods for flash lamps and reflects improved homogeneity with respect to glass rods known in the art. A quality index of 0.090 or less for the provided glass rods provides good robotic handling and thus allows for fully automated manufacture of flash lamps. A low value for the quality index indicates the desired homogeneity of the glass rods, since the overall relative length variation of the semi-major axis (tlv major ) must be low. Therefore, a low tlv majorThe value provides smooth robotic manipulation, especially prior to melting the glass rod and subsequent fabrication into a flash lamp. A low value for the quality index also indicates and provides low relative local area variability (lav), identified at the cross-sectional location with the longest semi-major axis length of 50 equidistant cross-sectional locations. A low value for relative local area variability (lav) establishes good fusion between the joined glass and metal electrodes.

[0014] The homogeneity of the glass rod allows smooth mechanical robotic manipulation, since variations and non-uniformities in thickness are minimized to the extent that there is no stalling of the glass rod in the robot. Furthermore, during the manufacture of the flash lamp, the glass rod must be heated. A homogeneous glass rod, having only a small relative local area variation lav, can be heated uniformly and consistently to the desired narrow temperature range. The manufacturing temperature of the flash lamp is high, since the glass composition used needs to be melted only at high temperatures, which is represented by the characteristic that the T4 temperature is equal to or higher than 1400°C. The glass rods according to the invention undergo less temperature deviations during the manufacturing stages, due to their high homogeneity with respect to the cross-sectional area and mass constancy along the length of said glass rod. Advantageously, this results in reduced glass fracture, both during the manufacture itself and in the final product.

[0015] In a second aspect, the present invention relates to a set of glass rods. Advantageously, the homogeneity of the glass rods according to the invention is reflected both in the individual glass rods provided and at the bulk level, comprising at least 40 glass rods in a set.

[0016] In a third aspect, the present invention provides a method for producing a glass rod, comprising the steps of: Providing a reactor (1) comprising a lower discharge opening (2), - heating the glass raw material in the reactor to obtain a glass melt (3); The glass melt is at least partially cooled to 10° C. 2.5heating to a temperature T2.5, defined as the temperature at which the solution has a viscosity of 100 dPa s; withdrawing the glass melt from the reactor at a withdrawal temperature and a glass melt withdrawal rate; and increasing the drawing temperature to control the drawing speed of the glass melt and / or adjusting the pressure on the glass melt to control the drawing speed of the glass melt; cooling and / or shaping the glass melt to obtain a glass rod (5) and / or to obtain a glass rod (5) according to the disclosure; and the glass melt has a glass composition having a T4 temperature of 1400° C. or more, where T4 is the glass melt composition having a temperature of 10 4 The temperature at which the composition has a viscosity of about 100 dPa·s.

[0017] The manufacturing process of glass compositions with high melting points, for example characterized by a T4 temperature of 1400°C or higher, and related products, is technically very challenging, especially when a narrow temperature range and strict control of the flow rate at high production temperatures are required. Therefore, the inventors have established conditions that allow for the control of the withdrawal of the glass melt from the reactor. Controlling the withdrawal rate of the glass melt by increasing the withdrawal temperature and / or adjusting the pressure on the glass melt provides two respective measures that can be used independently or in combination. Both of those measures are delicate and require strict process monitoring and control to control the withdrawal rate of the glass melt and especially to provide a withdrawal rate within a narrow preset range. Advantageously, said method allows for the production of glass rods according to the present disclosure.

[0018] Optionally, the method provides a glass rod or set of glass rods according to the present disclosure.

[0019] Therefore, we have determined that the minimized overall relative length variation of the semi-major axis (tlv major) and / or are highly homogeneous with respect to minimized relative local area variation (lav), thus tlv major Manufacturing conditions were established for producing glass rods with a desired low value for the quality index, defined as the sum of .lambda.+lav.

[0020] The production conditions can control the withdrawal of the glass melt from the reactor at a rate having a tolerance of 1% or less, and / or at a volumetric flow rate having a tolerance of 1% or less, and / or can control that the glass melt is withdrawn at a withdrawal temperature of at least 50°C above T4, with a tolerance of 10°C or 5°C or 3°C.

[0021] It is advantageous to control the withdrawal of the glass melt from the reactor within narrow (volume flow) speed boundaries and thus work with an approximately constant glass mass flow emerging from the reactor in order to minimize possible deviations in the resulting glass rod. Up until now, process control at this required level has not been technically feasible. The guaranteed constant glass mass flow at the discharge opening results in a glass rod with defined dimensions and thus a high degree of precision. The high precision is manifested in a minimized overall relative length variation of the semi-major axis and / or a minimized relative local area variation.

[0022] It can be advantageous for the glass melt to be drawn at a drawing temperature of at least 50° C. above T4 with a tolerance of 10° C., or 5° C., or 3° C., because the viscosity must be large enough to provide flow conditions for the glass melt at the stage of drawing the glass melt into the rod. At the same time, deviations in the temperature of the glass melt at the drawing stage may have to be kept small, for example with a tolerance of 10° C., or 5° C., or 3° C., to avoid inhomogeneities in the glass melt composition and the glass melt viscosity.

[0023] In another aspect, the invention relates to a flash lamp including a glass rod according to the present disclosure, the flash lamp further including an electrode (e.g., a tungsten or molybdenum electrode), and quartz glass, the glass sealing the quartz glass to the electrode.

[0024] In a fourth aspect, the present invention relates to the use of a glass rod according to the invention for joining a metal article to a glass member and / or for a flash lamp.

[0025] In a fifth aspect, the present invention provides a method for producing a gyro having a length l rod , average half-major axis length l major(a) , and the average semi-minor axis length l minor(a) A glass rod having a length l rod is 100 to 1600 mm, Within the cross section of the glass rod, l major(n) is the distance from the center of mass of the cross section to the farthest boundary of the glass rod within the cross section, and l minor(n) is the distance from the center of mass of the cross section to the nearest boundary of the glass rod within the cross section, and l major(n) and minor(n) can be the same or different from The glass rod is 10 4 The glass composition has a T4 temperature of 1400°C or more, which is defined as the temperature at which the glass composition has a viscosity of 100 dPa·s, The average semi-major axis length l major(a) is 0.9 to 3.1 mm, and the semi-minor axis length l minor(n) is 0.9 to 3.1 mm, The semi-major axis length l major(n) is the average semi-major axis length l of the 50 equidistant cross-sectional positions major(a) and / or The semi-minor axis length l minor(n) is within a tolerance of 10%, 5%, or 2% at each equidistant position relative to the average semi-minor axis length of the 50 equidistant cross-sectional positions, The 50 equidistant sections are arranged along the length l of the glass rod. rod The initial position is 0.01×l. rod Starting at position l, and adding an additional increment of 0.02 x l for each successive position rod is used, Regarding the glass rod.

[0026] In a sixth aspect, the present invention provides a method for producing a gyro having a length l rod , average half-major axis length l major(a) , and the average semi-minor axis length l minor(a) A glass rod having a length l rod is 100 to 1600 mm, Within the cross section of the glass rod, l major(n) is the distance from the center of mass of the cross section to the farthest boundary of the glass rod within the cross section, and l minor(n) is the distance from the center of mass of the cross section to the farthest boundary of the glass rod within the cross section, and l major(n) and minor(n) can be the same or different from The glass rod is 10 4 The glass composition has a T4 temperature of 1400°C or more, which is defined as the temperature at which the glass composition has a viscosity of 100 dPa·s, The glass rod has an average local ellipticity of 50 × (l major(n) -l minor(n) ) / (l major(n) +l minor(n) ) and has a mean ellipticity defined as the local ellipticity is sampled at 50 equidistant locations along the glass rod, and the average ellipticity is less than or equal to 0.20, less than 0.10, less than 0.050, or less than 0.030 at each equidistant location; The 50 equidistant sections are arranged along the length l of the glass rod. rod The initial position is 0.01×l. rod Starting at position l, and adding an additional increment of 0.02 x l for each successive position rod is used, Regarding the glass rod.

[0027] In a seventh aspect, the present invention provides a method for producing a gyro having a length l rod , average half-major axis length l major(a) , and the average semi-minor axis length l minor(a) A glass rod having a length l rod is 100 to 1600 mm, Within the cross section of the glass rod, l major(n) is the distance from the center of mass of the cross section to the farthest boundary of the glass rod within the cross section, and l minor(n) is the distance from the center of mass of the cross section to the nearest boundary of the glass rod within the cross section, and l major(n) and minor(n) can be the same or different from The glass rod is 10 4 The glass composition has a T4 temperature of 1400°C or more, which is defined as the temperature at which the glass composition has a viscosity of 100 dPa·s, Overall relative length variation of the semi-minor axis (tlv minor ) less than 0.040, TLV minor is determined as the absolute difference between the shortest and longest semi-minor axis lengths of the 50 equidistant cross-sectional locations, normalized by the average semi-minor axis length of the 50 equidistant cross-sectional locations; and / or has a relative overall area variation (tav) of less than 0.100, where tav is determined as the absolute difference between the smallest cross-sectional area at one cross-sectional location and the largest cross-sectional area of ​​said 50 equidistant cross-sectional locations, normalized by the average cross-sectional area of ​​said 50 equidistant cross-sectional locations; The 50 equidistant sections are arranged along the length l of the glass rod. rod The initial position is 0.01×l. rod Starting at position l, and adding an additional increment of 0.02 x l for each successive position rod is used, Regarding the glass rod.

[0028] Description of the invention Glass Rod In a first aspect, the present invention provides a method for manufacturing a gyro having a length l rod , average half-major axis length l major(a), and the average semi-minor axis length l minor(a) A glass rod having a length l rod is 100 to 1600 mm, Within the cross section of the glass rod, l major(n) is the distance from the center of mass of the cross section to the farthest boundary of the glass rod within the cross section, and l minor(n) is the distance from the center of mass of the cross section to the nearest boundary of the glass rod within the cross section, and l major(n) and minor(n) can be the same or different from The glass rod is 10 4 The glass composition has a T4 temperature of 1400°C or more, which is defined as the temperature at which the glass composition has a viscosity of 100 dPa·s, Overall relative length variation of the semimajor axis (tlv major ), relative local area variation (lav), and tlv major +lav, tlv major is determined as the absolute difference between (a) the shortest semi-major axis length of 50 equidistant cross-sectional locations and (b) the longest semi-major axis length of said 50 equidistant cross-sectional locations, and the average value l of the semi-major axis lengths of said 50 equidistant cross-sectional locations major(a) is normalized by The 50 equidistant sections are arranged along the length l of the glass rod. rod The initial position is 0.01×l. rod Starting at position l, and adding an additional increment of 0.02 x l for each successive position rod is used, lav is determined as (c) the absolute difference between the cross-sectional area at the cross-sectional location having the longest semi-major axis length of the 50 equidistant cross-sectional locations and (d) the average of the cross-sectional areas of the 50 equidistant cross-sectional locations, normalized by the average of the cross-sectional areas of the 50 equidistant cross-sectional locations; The quality index is 0.090 or less, 0.070 or less, or 0.050 or less; Regarding the glass rod.

[0029] The glass rod according to the invention is described in terms of its geometric (mathematical) properties, namely, its length l rod , average half-major axis length l major(a) , and the average semi-minor axis length l minor(a) and the length l rod In its most perfect geometric form, the glass rod can be a cylinder having one length and one radius, in which case the average semi-major axis length l major(a) and the mean semi-minor axis length l minor(a) are identical, and the radius is assumed to be one and the same value along the entire length of the glass rod, regardless of the cross section being measured. However, industrially manufactured glass rods exhibit slight geometric variations and cannot be mathematically perfectly cylindrical, i.e., the circular base may be an ellipse or ellipse-like base, which is the base of the length l major(a) having a semi-major axis and length l minor(a) In addition, industrially manufactured glass rods may exhibit variations in the semi-major and semi-minor axes along the length of the glass rod. For purposes of describing glass rods according to the present invention, assume that the glass rod has a length l rod , average half-major axis length l major(a) , and the average semi-minor axis length l minor(a) Furthermore, to evaluate and describe the homogeneity of the glass rod according to the present invention, 50 equidistant cross-sectional positions are measured. The 50 equidistant cross-sectional positions are determined over the length l of the glass rod. rod The initial position is 0.01×l. rod Starting at position l, and adding an additional increment of 0.02 x l for each successive position rod is used, and the geometric related parameters are statistically calculated, i.e., the semi-major axis length l major(n) and calculate how much the local areas in the cross-section differ from their respective average values.

[0030] The above concepts and disclosures provide a method for determining the thickness of a glass rod by measuring the thickness of the glass rod. major(n) is the distance from the center of mass of the cross section to the farthest boundary of the glass rod within the cross section, and l minor(n)is the distance from the center of mass of the cross section to the nearest boundary of the glass rod within the cross section, and l major(n) and minor(n) It is consistent with the fact that it can be the same or different. major(n) and minor(n) If l and l are different, the two parameters relate to the distances from the center of mass of the cross section to the farthest and nearest boundaries of the glass rod within the cross section, respectively. major(n) and l minor(n) The values ​​for can be derived from the maximum and minimum diameters in the cross section, where l and major(n) and l minor(n) The maximum and minimum diameters were divided by a factor of 2 to obtain .times. ...

[0031] The geometric related parameters derived in this disclosure, such as the overall relative length variation of the semi-major axes (tlv major ), relative local area variation (lav), quality index, mean ellipticity, and total relative length variation of the semiminor axis (tlv minor ), and the relative total area variation (tav) are the result of "normalization", e.g., by division of the associated mean value, and are therefore dimensionless. This type of data extraction and representation is considered useful and allows a better comparison of the geometric fidelity of different glass rods, regardless of their absolute dimensionality.

[0032] In one embodiment, the length l rod is 100 mm or more, 150 mm or more, 200 mm or more, 250 mm or more, 300 mm or more, 400 mm or more, 500 mm or more, 600 mm or more, or 700 mm or more. rod is 1600 mm or less, 1550 mm or less, 1500 mm or less, 1450 mm or less, 1400 mm or less, 1300 mm or less, 1200 mm or less, 1100 mm or less, or 1000 mm or less. rodare 100~1600mm, 150mm~1550mm, 200mm~1500mm, 250mm~1450mm, 300mm~1400mm, 400mm~1300mm, 500mm~1200mm, 600mm~1100mm, or 700mm~1000mm.

[0033] The glass rod is 10 4 The present invention includes glass compositions having a T4 temperature of 1400° C. or more, defined as the temperature at which the glass has a viscosity of 1000 dPa·s. In one embodiment, the glass composition has a T4 temperature of 1400° C. or more, 1450° C. or more, 1500° C. or more, or 1550° C. or more. In one embodiment, the glass composition has a T4 temperature of 1900° C. or less, 1850° C. or less, 1800° C. or less, or 1750° C. or less. In one embodiment, the glass composition has a T4 temperature of 1400° C. to 1900° C., 1450° C. to 1850° C., 1500° C. to 1800° C., or 1550° C. to 1750° C. The T4 temperature is specified according to ISO 7884-2:1998-02. Viscosity values ​​can generally be measured using a rotational viscometer, for example as described in DIN ISO 7884-2:1998-2.

[0034] To evaluate the homogeneity of the glass rod, i.e., its geometric fidelity, the overall relative length variation of the semi-major axis (tlv major ) is calculated, the relative local area variation (lav) is calculated, and tlv major A quality index, defined as the sum of +lav, is calculated.

[0035] Parameter tlv major is determined as the absolute difference between (a) the shortest semi-major axis length of 50 equidistant cross-sectional locations and (b) the longest semi-major axis length of said 50 equidistant cross-sectional locations, and the average value l of the semi-major axis lengths of said 50 equidistant cross-sectional locations major(a) is normalized by

[0036] The parameter lav is determined as the absolute difference between (c) the cross-sectional area at the cross-sectional location having the longest semi-major axis length of the 50 equidistant cross-sectional locations and (d) the average value of the cross-sectional areas of the 50 equidistant cross-sectional locations, normalized by the average value of the cross-sectional areas of the 50 equidistant cross-sectional locations.

[0037] In one embodiment of the glass rod, the quality index is 0.090 or less, 0.080 or less, 0.070 or less, 0.060 or less, or 0.050 or less. In one embodiment of the glass rod, the quality index is 0.004 or more, 0.008 or more, 0.012 or more, 0.016 or more, or 0.020 or more. In one embodiment of the glass rod, the quality index is 0.004 to 0.090, 0.008 to 0.080, 0.012 to 0.070, 0.016 to 0.060, or 0.020 to 0.050.

[0038] In one embodiment, the glass rod has a lav of less than 0.070, less than 0.060, or less than 0.050. In one embodiment, the glass rod has a lav of 0.002 or more, 0.004 or more, or 0.006 or more. In one embodiment, the glass rod has a lav of 0.002 to 0.070, 0.004 to 0.060, or 0.006 to 0.050.

[0039] In one embodiment, the glass rod has a tlv of less than 0.070, less than 0.060, or less than 0.050. major In one embodiment, the glass rod has a tlv of 0.002 or more, 0.004 or more, or 0.006 or more. major In one embodiment, the glass rod has a tlv of 0.002 to 0.070, 0.004 to 0.060, or 0.006 to 0.050. major has.

[0040] In one embodiment of the glass rod, the average semi-major axis length l major(a) is 0.9 to 3.1 mm, and the average semi-minor axis length l minor(a)is 0.9 to 3.1 mm, The semi-major axis length l major(n) is the average semi-major axis length l of the 50 equidistant cross-sectional positions major(a) and / or The semi-minor axis length l minor(n) is within a tolerance of 10%, 5%, or 2% at each equidistant location relative to the average semi-minor axis length of said 50 equidistant cross-sectional locations.

[0041] In one embodiment of the glass rod, the average semi-major axis length l major(a) is 0.9 to 3.1, and the average semi-minor axis length l minor(a) In one embodiment of the glass rod, the average semi-major axis length l major(a) is 1.2 to 2.8, and the average semi-minor axis length l minor(a) In one embodiment of the glass rod, the average semi-major axis length l major(a) is 1.5 to 2.5, and the average semi-minor axis length l minor(a) is 1.5~2.5mm.

[0042] In one embodiment of the glass rod, the semi-major axis length l major(n) is within a tolerance of 10%, 5%, or 2% at each equidistant location relative to the average semi-major axis length of said 50 equidistant cross-sectional locations.

[0043] In one embodiment of the glass rod, the semi-major axis length l major(n) is the average semi-major axis length l of the 50 equidistant cross-sectional positions major(a) For each of the above, the tolerance is 0.3 mm or less, 0.2 mm or less, 0.1 mm or less, or 0.05 mm or less at equidistant positions.

[0044] In one embodiment of the glass rod, the semi-minor axis length l minor(n) is within a tolerance of 10%, 5%, or 2% at each equidistant location relative to the average semi-minor axis length of said 50 equidistant cross-sectional locations.

[0045] In one embodiment of the glass rod, the semi-minor axis length l major(n) is within a tolerance of 0.3 mm or less, 0.2 mm or less, 0.1 mm or less, or 0.05 mm or less at each equidistant position with respect to the average semi-minor axis length of said 50 equidistant cross-sectional positions.

[0046] In one embodiment of the glass rod, the curvature is 0.030 to 0.300 mm, measured according to DIN EN ISO 1101:2017-09 and at a support distance of 300 mm. In one embodiment, the curvature is 0.030 mm or more, 0.050 mm or more, 0.070 mm or more, or 0.100 mm or more. In one embodiment, the curvature is 0.300 mm or less, 0.270 mm or less, 0.230 mm or less, or 0.200 mm or less. In one embodiment, the curvature is 0.030 mm to 0.300 mm, 0.050 mm to 0.270 mm, 0.070 mm to 0.230 mm, or 0.100 mm to 0.200 mm.

[0047] In one embodiment, the glass rod has a diameter of 2×(l major(n) -l minor(n) ) / (l major(n) +l minor(n) ), the average ellipticity is sampled at 50 equidistant positions n along the glass rod, and an average is calculated, and the average ellipticity is 0.20 or less, less than 0.10, less than 0.050, or less than 0.030 at each equidistant position. In one embodiment, the glass rod has an average ellipticity sampled at 50 equidistant positions along the glass rod of 0.002 or more, 0.005 or more, 0.010 or more, or 0.015 or more. In one embodiment, the glass rod has an average ellipticity sampled at 50 equidistant positions along the glass rod of 0.002 to 0.20, 0.005 to 0.10, 0.010 to 0.050, or 0.015 to 0.030.

[0048] In one embodiment, the glass rod has a total relative length variation of the semi-minor axis (tlv minor ) less than 0.040, TLV minor is determined as the absolute difference between the shortest and longest semi-minor axis lengths of the 50 equidistant cross-sectional locations, normalized by the average semi-minor axis length of the 50 equidistant cross-sectional locations.

[0049] In one embodiment, the glass rod has a tlv of less than 0.040, or less than 0.030. minor In one embodiment, the glass rod has a tlv of 0.005 or more, or 0.010 or more. minor In one embodiment, the glass rod has a tlv of 0.005 to 0.040, or 0.010 to 0.030. minor has.

[0050] In one embodiment, the glass rod has a relative overall area variation (tav) of less than 0.100, where tav is determined as the absolute difference between the smallest cross-sectional area at one cross-sectional location and the largest cross-sectional area of ​​the 50 equidistant cross-sectional locations, normalized by the average cross-sectional area of ​​the 50 equidistant cross-sectional locations.

[0051] In one embodiment, the glass rod has a tav of less than 0.100, less than 0.080, or less than 0.060. In one embodiment, the glass rod has a tav of 0.005 or more, 0.010 or more, or 0.020 or more. In one embodiment, the glass rod has a tav of 0.005 to 0.100, 0.010 to 0.080, or 0.020 to 0.060.

[0052] It is known to those skilled in the art that numerical values ​​relating to measurements are subject to measurement errors that constrain their precision. For this reason, the common practice in scientific and technical literature should be applied in this disclosure, namely that the last decimal place of a numerical value indicates its degree of precision. If no margin of error is otherwise given, the maximum margin is ascertained by applying a rounding technique to the last decimal place, e.g. for a (measured) value of 3.5, the margin of error is 3.45 to 3.54.

[0053] In one embodiment, the glass rod has one or more of the following characteristics: fewer than 10, fewer than 5, or fewer than 2 bubbles, where the length of the bubbles is at least 0.5 mm, measured as the longest linear distance in the bubble; and / or the length of the bubble, measured as the longest straight line distance along the bubble, is less than 70 mm, less than 50 mm, or less than 10 mm; and / or no bubble spread of more than 100 mm, where bubble spread is defined as the occurrence of a series of bubbles aligned one after the other along the length of the glass rod, the distance between any two adjacent bubbles being less than the length of the longest bubble in the series; It is characterized by:

[0054] Individual bubbles can be observed with the naked eye, for example using a light table, and can be captured by photography. Individual bubbles can have an approximately spherical shape, but can also appear as elongated, e.g. elliptical, bubbles, also called airlines, whose length is measured along the major axis. Elongated bubbles may not have a geometrically well-defined shape and therefore may be irregular in shape. A bubble is counted if its length, measured as the longest linear distance in said bubble, is at least 0.5 mm. If more than one bubble is observed, they may appear in the form of a spread.

[0055] In one embodiment, the glass rod has a bubble count of less than 10, less than 5, less than 2, or 0, wherein the bubble length is at least 0.5 mm, measured as the longest linear distance in the bubble.

[0056] Glass composition In one embodiment, the glass rod comprises, in weight percent, one or more or all of the following components: 70.0%~90.0% SiO 2 , 0.0%~25.0% B 2 O 3 , 0.0%~10.0% Al 2 O 3 , 0.0% to 10.0% of one or more alkaline earth metal oxides, 0.0% to 7.0% of one or more alkali metal oxides The glass composition includes:

[0057] In this disclosure, references to glass and glass compositions should be understood as equivalent.

[0058] In one embodiment, the glass is SiO 2 In one embodiment, the glass comprises SiO 2 In one embodiment, the glass comprises SiO 2 in an amount of 70.0 mass% to 90.0 mass%, 72.0 mass% to 89.0 mass%, 74.0 mass% to 88.0 mass%, 76.0 mass% to 87.0 mass%, or 78.0 mass% to 86.0 mass%.

[0059] In one embodiment, the glass is SiO 2in an amount of 70.0 mass% to 90.0 mass%, 72.0 mass% to 89.0 mass%, 74.0 mass% to 88.0 mass%, 76.0 mass% to 87.0 mass%, or 78.0 mass% to 86.0 mass%.

[0060] In one embodiment, the glass comprises one or more or all of the following components in weight percent: 70.0% to 90.0% SiO 2 , 0.0%~25.0% B 2 O 3 , 0.0%~10.0% Al 2 O 3 , 0.0% to 10.0% of one or more alkaline earth metal oxides, 0.0% to 7.0% of one or more alkali metal oxides.

[0061] In one embodiment, the glass comprises one or more or all of the following components in weight percent: 75.0% to 87.0% SiO 2 , 8.0%~22.0% B 2 O 3 , 1.0%~7.0% Al 2 O 3 , 0.25% to 5.0% of one or more alkaline earth metal oxides, 0.0% to 5.0% of one or more alkali metal oxides.

[0062] In the context of the present invention, the alkali metal oxide is specifically Li 2 O, Na 2 O and K 2 O, and alkaline earth metal oxides are specifically meant to include MgO, CaO, BaO, and SrO.

[0063] In one embodiment, the glass comprises, by weight, 0.0% to 10.0%, for example 1.0% to 9.0%, 2.0% to 8.0%, 3.0% to 7.0%, or 4.0% to 6.0% of one or more alkaline earth metal oxides.

[0064] In one embodiment, the glass comprises, by weight, 0.0% to 7.0%, for example 0.5% to 6.5%, 1.0% to 6.0%, 1.5% to 5.5%, or 2.0% to 5.0% of one or more alkali metal oxides.

[0065] In one embodiment, the glass comprises, in weight percent: [Table 1]

[0066] In one embodiment, the glass is B 2 O 3 In one embodiment, the glass comprises B 2 O 3 In one embodiment, the glass comprises B 2 O 3 in an amount of 1.0% to 25.0% by mass, 2.0% to 22.0% by mass, 4.0% to 20.0% by mass, 6.0% to 18.0% by mass, or 8.0% to 15.0% by mass.

[0067] In one embodiment, the glass is Al 2 O 3 In one embodiment, the glass comprises Al in an amount of 1.0% by weight or more, 2.0% by weight or more, 3.0% by weight or more, or 4.0% by weight or more. 2 O 3 In one embodiment, the glass comprises Al in an amount of 10.0% by weight or less, 9.0% by weight or less, 8.0% by weight or less, 7.0% by weight or less, or 6.0% by weight or less. 2 O 3 in an amount of 0.0% to 10.0% by mass, 1.0% to 9.0% by mass, 2.0% to 8.0% by mass, 3.0% to 7.0% by mass, or 4.0% to 6.0% by mass.

[0068] In one embodiment, the glass contains 0.0% to 5.0% BaO by mass, for example 0.5% to 4.5%, 1.0% to 4.0%, 1.5% to 3.5%, or 2.0% to 3.0%. In one embodiment, the glass contains 0.0% or more, 0.5% or more, 1.0% or more, 1.5% or more, or 2.0% or more BaO by mass. In one embodiment, the glass contains 5.0% or less, 4.5% or less, 4.0% or less, 3.5% or less, or 3.0% or less BaO by mass.

[0069] In one embodiment, the glass contains 0.0% to 3.0% CaO by mass, for example 0.2% to 2.8%, 0.4% to 2.6%, 0.6% to 2.4%, 0.8% to 2.2%, or 1.0% to 2.0%. In one embodiment, the glass contains 0.0% or more, 0.2% or more, 0.4% or more, 0.6% or more, 0.8% or more, or 1.0% or more CaO by mass. In one embodiment, the glass contains 3.0% or less, 2.8% or less, 2.6% or less, 2.4% or less, 2.2% or less, or 2.0% or less CaO by mass.

[0070] In one embodiment, the glass has a K content of 0.0% to 5.0%, for example 0.5% to 4.5%, 1.0% to 4.0%, 1.5% to 3.5%, or 2.0% to 3.0% by weight. 2 In one embodiment, the glass contains, by mass percent, 0.0% or more, 0.5% or more, 1.0% or more, 1.5% or more, or 2.0% or more K. 2 In one embodiment, the glass contains, by weight percent, 5.0% or less, 4.5% or less, 4.0% or less, 3.5% or less, or 3.0% or less K. 2 Contains O.

[0071] In one embodiment, the glass contains, by weight, 0.0% to 5.0%, e.g., 0.5% to 4.5%, 1.0% to 4.0%, 1.5% to 3.5%, or 2.0% to 3.0% Na. 2In alternative embodiments, the glass contains, by weight, 0.0% to 3.0%, e.g., 0.1% to 2.5%, 0.2% to 2.0%, 0.3% to 1.5%, or 0.4% to 1.0% Na. 2 In one embodiment, the glass contains, by mass percent, 0.0% or more, 0.1% or more, 0.2% or more, 0.3% or more, or 0.4% or more Na 2 In one embodiment, the glass contains, by weight percent, 3.0% or less, 2.5% or less, 2.0% or less, 1.5% or less, or 1.0% or less Na. 2 Contains O.

[0072] In one embodiment, the glass contains, by weight, 0.0% to 1.0%, for example 0.1% to 0.9%, 0.2% to 0.8%, 0.3% to 0.7%, or 0.4% to 0.6% Li. 2 In one embodiment, the glass contains, by mass percent, 0.0% or more, 0.1% or more, 0.2% or more, 0.3% or more, or 0.4% or more Li. 2 In one embodiment, the glass contains, by weight percent, 1.0% or less, 0.9% or less, 0.8% or less, 0.7% or less, or 0.6% or less Li. 2 Contains O.

[0073] In one embodiment, the glass contains 1000 ppm (by weight) or less of Fe. 2 O 3 , Fe 500 ppm or less (by mass) 2 O 3 Fe, 200 ppm (by mass) or less 2 O 3 Fe, 100 ppm (by mass) or less 2 O 3 , Fe 50 ppm or less (by mass) 2 O 3 or 20 ppm (by mass) or less of Fe 2 O 3 In one embodiment, the glass contains 1 ppm or more of Fe (by mass). 2 O 3 , 2 ppm or more of Fe (by mass) 2 O3 , 3 ppm or more of Fe (by mass) 2 O 3 , 5 ppm or more (by mass) of Fe 2 O 3 , 7 ppm or more of Fe (by mass) 2 O 3 or 10 ppm (by mass) or more of Fe 2 O 3 In one embodiment, the glass contains 1 to 1000 (by mass) ppm Fe. 2 O 3 , 2 to 500 (mass) ppm Fe 2 O 3 , 3 to 200 (mass) ppm Fe 2 O 3 , 5 to 100 (mass) ppm Fe 2 O 3 , 7 to 50 (mass) ppm Fe 2 O 3 or 10 to 20 ppm (by mass) of Fe 2 O 3 Includes.

[0074] In one embodiment, the glass comprises, in weight percent: [Table 2]

[0075] In one embodiment, the glass comprises, in weight percent: [Table 3]

[0076] In one embodiment, the glass is free of one or more or all of lithium, magnesium, potassium, calcium, sodium, lead, arsenic, and antimony.

[0077] When this description refers to a glass that is free of an ingredient or does not contain a particular ingredient, or includes the hypothetical case of 0% by weight of that ingredient, it should be understood that this ingredient may be present at most as an impurity. This means that it is not added in any significant amount and is not added intentionally. The term "ingredient" refers to the elemental species itself as well as any molecule that contains that element. An insubstantial amount should be understood as less than 100 ppm by weight, preferably less than 50 ppm, and most preferably less than 10 ppm, for all intentionally added ingredients.

[0078] In one embodiment, the glass composition has a viscosity of 0.95×10 as measured in the temperature range of 20 to 300° C. and specified according to ISO 7991:1987. -6 ~3.20×10 -6 / K. In one embodiment, the glass composition has a thermal expansion coefficient of at least 0.95×10 -6 / K, at least 1.00 × 10 -6 / K, at least 1.05 × 10 -6 / K, at least 1.10 × 10 -6 / K, at least 1.20 × 10 -6 / K, or at least 1.50 × 10 -6 / K. In one embodiment, the glass composition has a thermal expansion coefficient of 3.20×10 -6 / K or less, 3.00×10 -6 / K or less, 2.70×10 -6 / K or less, 2.20×10 -6 / K or less, 2.00×10 -6 / K. In one embodiment, the glass composition has a thermal expansion coefficient of 0.95×10 -6 ~3.20×10 -6 / K, 1.00×10 -6 ~3.00×10 -6 / K, 1.05×10 -6 ~2.70×10 -6 / K, 1.10×10 -6 ~2.20×10 -6 / K, 1.20×10 -6 ~2.20×10-6 / K, 1.50×10 -6 ~2.00×10 -6 / K.

[0079] In one embodiment, the glass composition has a transition temperature of 600-750°C as measured by ISO 7884-8. In one embodiment, the glass composition has a transition temperature of at least 600°C, at least 615°C, at least 635°C, at least 650°C, at least 680°C, or at least 695°C. In one embodiment, the glass composition has a transition temperature of 750°C or less, 730°C or less, or 710°C or less. In one embodiment, the glass composition has a transition temperature of 600-750°C, 615-730°C, or 635-710°C.

[0080] Glass rod set In one embodiment, the present invention relates to a glass rod set comprising at least 40 glass rods according to the present disclosure. Advantageously, said set provides homogeneous glass rods with little geometric variation and anomalies between different rods. Thus, using one set of glass rods, robotic or other automated processes can be performed without supervision. Advantageously, this allows for efficient manufacturing of further parts, such as flash lamps, that rely on glass rods as a precursor part.

[0081] In one embodiment, the set includes at least 40 glass rods, at least 70 glass rods, or at least 100 glass rods. In one embodiment, the set includes no more than 1000 glass rods, no more than 700 glass rods, or no more than 400 glass rods. In one embodiment, the set includes between 40 and 1000 glass rods, between 70 and 700 glass rods, or between 100 and 400 glass rods.

[0082] In one embodiment of the set of glass rods, at least 80% of the glass rods have one or more of the following characteristics: the absence of bubbles, defined as longitudinal voids completely enclosed within the glass rod, preferably formed by gas inclusions in the glass, where the gas may be gaseous at 20° C. and / or may condense after cooling, and bubbles with reduced pressure are formed, having a diameter of 0.15 mm or less in the longest extent in the cross-sectional direction of the glass rod and a length of 50 mm or less along the longest extent of the glass rod, being essentially free of open cells, wherein the length of a cell is at least 0.5 mm, measured as the longest linear distance in said cell; the absence of inclusions, defined as foreign bodies completely enclosed within the glass rod, having a size of 100 μm or more, preferably metallic and / or non-metallic particle inclusions; has.

[0083] Open bubbles are visually visible as bubbles on the surface of the glass rod. They may occur after a previously completely trapped void has burst open. Thus, they no longer hold and / or trap gas inclusions in the glass.

[0084] In one embodiment of the set of glass rods, at least 80%, at least 85%, at least 90%, at least 95%, at least 98%, or at least 99% of the glass rods have one or more of the above characteristics.

[0085] In one embodiment of the set of glass rods, at least 99% of the glass rods are free of bubbles, defined as longitudinal voids completely trapped within the glass rod, preferably formed by gas inclusions in the glass, where the gas may be gaseous at 20°C and / or may condense after cooling, and bubbles with reduced pressure are formed, having a diameter of 0.15 mm or less in the longest extent in the cross-sectional direction of the glass rod and a length of 50 mm or less along the longest extent of the glass rod.

[0086] In one embodiment of the set of glass rods, at least 99% of said glass rods are essentially free of open bubbles, wherein the length of a bubble is at least 0.5 mm, measured as the longest linear distance in said bubble.

[0087] In one embodiment of the set of glass rods, at least 99% of said glass rods are free of inclusions, preferably metallic particle inclusions and / or non-metallic particle inclusions, defined as foreign bodies completely enclosed within the glass rods having a size of 100 μm or more.

[0088] Glass rod manufacturing method In one embodiment, the present invention provides a method for producing a glass rod, comprising the steps of: Providing a reactor (1) comprising a lower discharge opening (2), - heating the glass raw material in the reactor to obtain a glass melt (3); The glass melt is at least partially cooled to 10° C. 2.5 heating to a temperature T2.5, defined as the temperature at which the solution has a viscosity of 100 dPa s; withdrawing the glass melt from the reactor at a withdrawal temperature and a glass melt withdrawal rate; and increasing the drawing temperature to control the drawing rate of the glass melt and / or adjusting the pressure on the glass melt to control the drawing rate of the glass melt; cooling and / or shaping the glass melt to obtain a glass rod (5) and / or to obtain a glass rod (5) according to any one of claims 1 to 7. The glass melt has a glass composition having a T4 temperature of 1400° C. or more, where T4 is the glass melt composition having a T4 temperature of 10 4 The temperature at which the composition has a viscosity of about 100 dPa·s.

[0089] The drawing temperature of the glass melt can be measured by an IR pyrometer (6). In one embodiment, the drawing temperature is monitored with respect to and / or as the surface temperature of the glass melt at the glass melt-air interface, where the maximum temperature at the glass melt-air interface is used as a reference value for the drawing temperature. In an alternative embodiment, the drawing temperature is measured and / or controlled at the discharge opening.

[0090] Preferably, the pressure above the glass melt is measured by a pressure sensor (7). Thus, the pressure above the glass melt can be related to the conditions in the reactor and above the glass melt.

[0091] The withdrawal rate of the glass melt from the reactor quantifies the amount of glass melt leaving the reactor per unit time and can be expressed in m / min in terms of the length of the glass rod exiting the lower discharge opening and / or as a volumetric flow rate in ml / min, both parameters being related to each other through the cross-sectional area of ​​the glass rod and relating to a time-averaged value.

[0092] Optionally, the method of making a glass rod provides a glass rod or set of glass rods according to the present disclosure.

[0093] We have found that the minimized overall relative length variation (tlv major ) and / or are highly homogeneous with respect to minimized relative local area variation (lav), thus tlv major Manufacturing conditions were established for producing glass rods with a desired low value for the quality index, defined as the sum of .lambda.+lav.

[0094] In one embodiment, the reactor including the lower discharge opening is a batch reactor. In an alternative embodiment, the reactor including the lower discharge opening is a continuous reactor.

[0095] In one embodiment, heating the glass frits in the reactor to obtain a glass melt comprises adding SiO 2 , B 2 O 3 , Al 2 O 3 The method includes providing a batch or mixture of oxides, which may be selected from the list of one or more alkaline earth metal oxides, and one or more alkali metal oxides, and heating the batch or mixture of oxides to melt them.

[0096] In one embodiment, the glass melt is at least partially melted at 10 2.5 The melting temperature T2.5 is defined as the temperature at which the glass has a viscosity of 10 ...

[0097] In one embodiment, the glass melt is at least partially heated to a temperature T2.3. In one embodiment, the glass melt is at least partially heated to a temperature equal to or lower than T2.1. In one embodiment, the glass melt is at least partially heated to a temperature between T2.5 and T2.1.

[0098] In one embodiment, the step of at least partially heating the glass melt to a temperature T2.5 is carried out in a batch or continuous reactor for a time sufficient to establish a homogeneous glass melt. Depending on the selected mixture of oxides in the raw materials and the type of reactor (continuous or batch), it is known to those skilled in the art how to establish the temperature T2.5 to obtain a homogeneous glass melt.

[0099] In one embodiment, the entire glass melt in the reactor is heated to a temperature T2.5. In one embodiment, the entire glass melt in the reactor is heated to a temperature T2.5 to T2.1.

[0100] The temperature in the reactor can be assessed and controlled using a suitable temperature probe capable of operating at the high temperatures required for the glasses according to the invention.

[0101] It is preferred that the viscosity of the glass melt not be less than 100 dPas. Heating the glass to a very low viscosity increases the erosion of the melting vessel walls and can introduce impurities into the glass composition. Furthermore, low viscosities correspond to very high temperatures, which require undesirably high power consumption.

[0102] The production conditions include controlling the withdrawal of the glass melt from the reactor at the withdrawal temperature and at the glass melt withdrawal rate, increasing the withdrawal temperature to control the glass melt withdrawal rate, and / or adjusting the pressure above the glass melt to control the glass melt withdrawal rate.

[0103] The drawing temperature of the glass melt is related to the temperature of the glass melt, which can be measured using a suitable temperature probe, for example an IR pyrometer, which makes it possible to monitor and control the process in such a way that the intended tolerances on the temperature must be maintained.

[0104] In one embodiment of the method, the glass melt is withdrawn at a withdrawal temperature of at least 50° C. above T4, preferably 50-130° C. above T4 with a tolerance of 10° C., or 5° C., or 3° C., wherein preferably withdrawal of the glass melt from the reactor is performed through a discharge opening.

[0105] In one embodiment, the discharge opening is a nozzle having a conical internal shape. Advantageously, the nozzle can be designed and / or used to control the characteristics of the fluid flow as the glass melt leaves the reactor. The nozzle thus makes it possible to control the withdrawal speed of the glass melt as well as the shape of the glass melt stream leaving the reactor. The withdrawal speed of the glass melt can be expressed in m / min and can be related to the area of ​​the length of the glass rod produced per hour, or as a volumetric flow rate in ml / min related to the volume of glass melt leaving the reactor per unit time.

[0106] In one embodiment, the discharge opening can be heated independently. Those skilled in the art are aware that at the high temperatures required for glass production, temperature gradients in the glass melt can occur in the reactor. Therefore, it is advantageous to monitor the temperature of the glass melt in the reactor, preferably including the discharge opening, if necessary, and control and / or regulate the temperature via an independent heating means at the discharge opening. Such an independent heating means can be, for example, an electromagnetic coil.

[0107] In one embodiment of the method, the drawing temperature is increased to control the drawing rate of the glass melt with a tolerance of 2% or less, or 1% or less.

[0108] In one embodiment of the method, the pressure on the glass melt is adjusted to control the withdrawal rate of the glass melt to within a tolerance of 2% or less, or 1% or less.

[0109] In one embodiment of the method, increasing the drawing temperature to control the drawing rate of the glass melt comprises increasing the drawing temperature in temperature increments of 1° C. and increasing the drawing temperature by 30° C., 20° C., 10° C., 5° C., or 3° C. during drawing of the glass melt. Depending on the type of reactor and reactor conditions, said regime of temperature increase during drawing of the glass melt can result in obtaining a glass rod according to the invention, i.e. a homogeneous, geometrically defined glass rod.

[0110] It is advantageous to control the withdrawal of the glass melt from the reactor within narrow (volume flow) speed boundaries and thus work with an approximately constant glass mass flow emerging from the reactor in order to minimize possible deviations in the resulting glass rod. The guaranteed constant glass mass flow at the discharge opening results in a glass rod with defined dimensions and thus high precision. The high precision is manifested in a minimized overall relative length variation of the semi-major axis and / or a minimized relative local area variation.

[0111] The withdrawal of the glass melt from the reactor can be described and quantified by a rate in "m / min" and / or by a volumetric flow rate in "ml / min". The withdrawal rate of the glass melt from the reactor should be very constant. For a given average withdrawal rate, a tolerance of 1% means that the maximum and minimum withdrawal rates should not deviate from each other by more than 1% based on the average withdrawal rate.

[0112] It is advantageous to control that the glass melt is drawn at a drawing temperature of at least 50° C. above T4 with a tolerance of 10° C., or 5° C., or 3° C., because the viscosity must be large enough to provide flow conditions for the glass melt at the stage of drawing the glass melt into a rod. At the same time, the deviation in the temperature of the glass melt at the drawing stage must be kept small, for example with a tolerance of 10° C., or 5° C., or 3° C., to avoid inhomogeneities in the composition of the glass melt and the viscosity of the glass melt. A tolerance of, for example, 10° C. during drawing means that the maximum and minimum temperatures cannot deviate from each other by more than 10° C. during one process run to produce a glass rod of one particular glass composition.

[0113] In one embodiment, the glass melt is drawn at a drawing temperature of 50-130°C above T4 with a tolerance of 10°C, or 5°C, or 3°C. The exact temperature of drawing the glass melt may depend on the glass composition and the type and geometric features of the reactor. It may be advantageous to control the drawing temperature of the glass melt within a narrow range with a tolerance of 10°C, or 5°C, or 3°C. This temperature control is usually automated, but can also be further controlled by the direct instruction of the operator during production. For example, at the beginning of the process, it may be necessary or necessary to reduce the temperature by 20°C or less, for example if the viscosity of the glass composition is too high, and / or to implement a feedback control of 50°C or less.

[0114] In one embodiment, the glass melt is drawn at a drawing temperature of 50 to 130° C. above T4, 55 to 125° C. above T4, 60 to 120° C. above T4, 65 to 115° C. above T4, 70 to 110° C. above T4, 75 to 105° C. above T4, or 80 to 100° C. above T4. In one embodiment, the glass melt is drawn at a temperature of 50° C. or more above T4, 55° C. or more above T4, 60° C. or more above T4, 65° C. or more above T4, 70° C. or more above T4, 75° C. or more above T4, or 80° C. or more above T4. In one embodiment, the glass melt is drawn at a temperature of 130° C. or less above T4, 125° C. or less above T4, 120° C. or less above T4, 115° C. or less above T4, 110° C. or less above T4, 105° C. or less above T4, or 100° C. or less above T4.

[0115] In one embodiment, the withdrawal of the glass melt from the reactor is carried out through a nozzle as a discharge opening. A suitable nozzle for the withdrawal of the glass melt comprises an alloy, where the alloy comprises 90% by weight or more of iridium. Advantageously, the nozzle can enable and / or ensure a smooth production process.

[0116] Cooling the glass melt to obtain a glass rod is performed after the glass melt has passed through the discharge opening. Advantageously, process conditions are established such that the average cooling rate of the glass rod is less than or equal to 2000 K / h until the T4 temperature is reached, which preserves the uniformity of the glass composition and the homogeneity of the glass rod. After the glass melt has been cooled to the T4 temperature, the subsequent cooling can proceed at a faster cooling rate.

[0117] In one embodiment, the average cooling rate of the glass rod is 1000 K / h or less, 500 K / h or less, 200 K / h or less, or 5 K / h or less. In one embodiment, the cooling rate of the glass rod is 1 K / h or more, 2 K / h or more, or 3 K / h or more. In one embodiment, the cooling rate of the glass rod is 1 K / h to 20 K / h, 2 K / h to 15 K / h, or 3 K / h to 10 K / h.

[0118] The shaping of the glass melt to obtain a glass rod takes place primarily at the discharge opening, i.e. as the glass melt leaves the reactor.

[0119] In one embodiment, the glass melt has a glass composition having a T4 temperature of 1400° C. or more, where T4 is the temperature at which the glass melt composition is heated to 100° C. 4 This is the temperature at which the liquid has a viscosity of dPa·s.

[0120] In one embodiment, the glass melt has a glass composition having a T4 temperature of 1400° C. or more, 1450° C. or more, 1500° C. or more, or 1550° C. or more. In one embodiment, the glass melt has a glass composition having a T4 temperature of 1900° C. or less, 1850° C. or less, 1800° C. or less, or 1750° C. or less. In one embodiment, the glass melt has a glass composition having a T4 temperature of 1400° C. to 1900° C., 1450° C. to 1850° C., 1500° C. to 1800° C., or 1550° C. to 1750° C.

[0121] In one embodiment of the method, the withdrawal of the glass melt from the reactor is at a speed of 2 to 50 m / min with respect to the length of the glass rod exiting the lower discharge opening, and / or the glass melt is withdrawn from the reactor at a volumetric flow rate of 15 to 150 ml / min.

[0122] In one embodiment of the method, the glass melt is withdrawn from the reactor at a speed of 2 m / min or more, 5 m / min or more, or 10 m / min or more. In one embodiment of the method, the glass melt is withdrawn from the reactor at a speed of 50 m / min or less, 40 m / min or less, or 30 m / min or less. In one embodiment of the method, the glass melt is withdrawn from the reactor at a speed of 2 to 50 m / min, 5 to 40 m / min, or 10 to 30 m / min.

[0123] In one embodiment of the method, the glass melt is withdrawn from the reactor at a volumetric flow rate of 15 to 150 ml / min, 25 to 120 ml / min, or 50 to 100 ml / min. In one embodiment of the method, the glass melt is withdrawn from the reactor at a volumetric flow rate of 15 ml / min or more, 25 ml / min or more, or 50 ml / min or more. In one embodiment of the method, the glass melt is withdrawn from the reactor at a volumetric flow rate of 150 ml / min or less, 120 ml / min or less, or 100 ml / min or less.

[0124] In one embodiment of the method, which is optionally a batch process, the method comprises the further step of interrupting the withdrawal of the glass melt from the reactor, preferably operated as a batch reactor, before reaching 90%, or 80%, or 70%, or 60%, or 50% consumption of the glass melt. In a batch process, an initial glass melt is produced and at a certain point it becomes possible to perform the withdrawal of the glass melt from the reactor. Before the start of the withdrawal, the amount of glass melt is 100%, regardless of whether it is normalized to volume or mass. The consumption of glass should be understood as the % amount of glass melt that is withdrawn from the reactor, i.e. formed into a glass rod. Advantageously, when the method is carried out batchwise, at least 50% of the glass melt from the reactor can be used and formed into a glass rod without loss of quality. It should be understood that the quality of the glass rod is manifested in the uniformity of the glass (melt) composition and in the high geometric homogeneity of the resulting glass rod.

[0125] If the glass melt composition begins to show abnormalities during the process, the drawing must be stopped to protect the quality of the glass rod already obtained. It should be understood that the process requires close monitoring and control, and possibly operator intervention. Glass melt composition abnormalities that may occur or be observed during the process include discoloration of the glass melt and the appearance of a milky color of or in the glass melt.

[0126] In one embodiment, the method further comprises the steps of: continuing to withdraw the glass melt from the reactor, preferably operated as a batch reactor, once consumption of 90% of the glass melt has been reached; and Heating the molten surface wherein heating the melting surface results in maintaining the withdrawal of the glass melt from the reactor at a rate within a tolerance of 1% or less and / or at a volumetric flow rate within a tolerance of 1% or less.

[0127] Advantageously, in the absence of any anomalies, the process, i.e. the withdrawal of the glass melt from the reactor, may be continued once 90% consumption of the glass melt has been reached, for which a melting surface needs to be heated in order to maintain the desired glass rod quality, whereby the heating of the melting surface results in maintaining the withdrawal of the glass melt from the reactor at a rate and / or at a volumetric flow rate with a tolerance of 1% or less.

[0128] Heating the melt surface acts to reduce viscosity, which is adjusted to offset the reduced hydrostatic pressure within the reactor. Optionally, heating the melt surface is controlled manually, i.e., by operator intervention, or via a preprogrammed time gradient.

[0129] Heating of the melt surface may rely on the introduction and combustion of combustion gases, which creates additional pressure inside the reactor. To achieve and control the pressure fluctuations, purge openings or valve-like openings can be used and the purge diameter can be selected to be variable. Based on lowering the glass level height in the reactor to 10 mm (h) and density (ρ) to 2.24 g / mL, the equation p = ρ h g [where g is 9.81 m / s 2 It is estimated that a pressure loss (p) of 220 Pa needs to be compensated for.

[0130] In one embodiment, adjusting the pressure on the glass melt includes one or more of the following means: hermetically sealing the reactor; and Compensating for the pressure drop at the lower discharge opening using compressed air. Includes.

[0131] In one embodiment, the method further comprises the step of: 2 and / or the contact surfaces of the reactor in contact with the glass melt are made of more than 70% by weight of ZrO 2 and / or the contact surface of the reactor in contact with the glass melt comprises a sintered material having more than 80% by weight, or more than 90% by weight, or more than 95% by weight of zirconium silicate.

[0132] Advantageously, control of the hydrostatic pressure makes it possible to establish and / or maintain a constant withdrawal of the glass melt from the reactor.

[0133] Hermetic sealing of the reactor and exhaust gases, e.g. CO 2 While these two measures, heating solely by electrical means to eliminate the need for heating, result in no internal pressure build-up, it may be necessary to compensate for the pressure drop at the lower discharge opening with pressurized air in order to maintain an approximately constant hydrostatic pressure during the course of the process.

[0134] In one embodiment, the glass rod, optionally obtained by the method, has a thermal expansion coefficient of 0.8 ppm / K to 4.5 ppm / K in the temperature range of 20°C to 300°C.

[0135] In one embodiment, the glass rod has a coefficient of thermal expansion of at least 0.95 ppm / K, at least 1.00 ppm / K, at least 1.05 ppm / K, at least 1.10 ppm / K, at least 1.20 ppm / K, or at least 1.50 ppm / K. In one embodiment, the glass rod has a coefficient of thermal expansion of 3.20 ppm / K or less, 3.00 ppm / K or less, 2.70 ppm / K or less, 2.20 ppm / K or less, or 2.00 ppm / K or less. In one embodiment, the glass rod has a thermal expansion coefficient of 0.95 ppm / K to 3.20 ppm / K, 1.00 ppm / K to 3.00 ppm / K, 1.05 ppm / K to 2.70 ppm / K, 1.10 ppm / K to 2.20 ppm / K, 1.20 ppm / K to 2.20 ppm / K, or 1.50 ppm / K to 2.00 ppm / K.

[0136] In one embodiment, the glass rod has a water content of at least 35 mmol / l, at least 40 mmol / l, at least 45 mmol / l, at least 50 mmol / l, or at least 55 mmol / l. In one embodiment, the glass rod has a water content of 250 mmol / l or less, 200 mmol / l or less, 150 mmol / l or less, 125 mmol / l or less, or 100 mmol / l or less. Thus, in a related embodiment, the glass has a water content of 35 to 250 mmol / l, 40 to 200 mmol / l, 45 to 150 mmol / l, 50 to 125 mmol / l, or 55 to 100 mmol / l.

[0137] The water content can be measured by IR spectroscopy at an absorption maximum at about 2700 nm, which is preferably determined in the IR absorption spectrum in the wavelength range 2500-6500 nm, assuming a standard absorption coefficient of 110 l·cm / mol for glass compositions according to the present disclosure.

[0138] Advantageously, a water content of at least 35 mmol / l or at least 55 mmol / l can help reduce the occurrence of glass fracture and / or glass anomalies upon repeated and multiple (re)heating and / or manufacturing of the glass.

[0139] Flash lamp In another aspect, the invention relates to a flash lamp including a glass rod according to the present disclosure, the flash lamp further including an electrode (e.g., a tungsten or molybdenum electrode), and quartz glass, the glass rod sealing the quartz glass to the electrode.

[0140] In one embodiment, there is provided a flash lamp comprising a metal electrode and a tube, the tube preferably comprising or consisting of glass, e.g., quartz glass, and further comprising a sealing glass, the sealing glass being incorporated from a glass rod according to the present disclosure.

[0141] In one embodiment, there is provided a flashlamp comprising an electrode and a quartz glass tube, said electrode and said quartz glass tube being joined by a glass rod seal according to the present disclosure.

[0142] The use of the glass rod according to the present disclosure as a sealing glass is advantageous because it provides an excellent sealing bond, i.e., fusion, between the electrodes and the glass tube, even during extreme and rapid temperature changes, thereby advantageously increasing the stability and lifespan of the manufactured flash lamps that undergo such extreme and rapid temperature changes during their life cycle, i.e., in use.

[0143] use In a further aspect, the present invention relates to the use of a glass rod according to the present disclosure for bonding a metal article to a glass member and / or for a flash lamp.

[0144] Advantageously, the homogeneity of the glass rod according to the invention allows smooth mechanical robotic manipulation, since variations and non-uniformities in thickness are minimized to the extent that there is no stalling of the glass rod in the robot. During the manufacture of the flash lamp, the glass rod must be heated. A homogeneous glass rod, having only small relative local area variations lav, can be heated uniformly and consistently to the desired narrow temperature range. The manufacturing temperatures of the flash lamp are high, since the glass composition used needs to be melted only at high temperatures, which is expressed in the characteristic that the T4 temperature is equal to or higher than 1400°C. The glass rods according to the invention undergo less temperature deviations during the manufacturing stages, due to their high homogeneity with respect to the cross-sectional area and mass constancy along the length of said glass rod. Advantageously, this leads to reduced glass fracture, both during the manufacture itself and in the final product.

[0145] Glass rod and glass composition In one embodiment, the present invention provides a method for producing a fluorophore having a length of l rod , average half-major axis length l major(a) , and the average semi-minor axis length l minor(a) A glass rod having a length l rod is 100 to 1600 mm, Within the cross section of the glass rod, l major(n) is the distance from the center of mass of the cross section to the farthest boundary of the glass rod within the cross section, and l minor(n) is the distance from the center of mass of the cross section to the nearest boundary of the glass rod within the cross section, and l major(n) and minor(n) can be the same or different from The glass rod is 10 4 The glass composition has a T4 temperature of 1400°C or more, which is defined as the temperature at which the glass composition has a viscosity of 100 dPa·s, Overall relative length variation of the semimajor axis (tlv major ), relative local area variation (lav), and tlv major +lav, tlvmajor is determined as the absolute difference between (a) the shortest semi-major axis length of 50 equidistant cross-sectional locations and (b) the longest semi-major axis length of said 50 equidistant cross-sectional locations, and the average value l of the semi-major axis lengths of said 50 equidistant cross-sectional locations major(a) is normalized by The 50 equidistant sections are arranged along the length l of the glass rod. rod The initial position is 0.01×l. rod Starting at position l, and adding an additional increment of 0.02 x l for each successive position rod is used, lav is determined as (c) the absolute difference between the cross-sectional area at the cross-sectional location having the longest semi-major axis length of the 50 equidistant cross-sectional locations and (d) the average of the cross-sectional areas of the 50 equidistant cross-sectional locations, normalized by the average of the cross-sectional areas of the 50 equidistant cross-sectional locations; the quality index is 0.090 or less, 0.070 or less, or 0.050 or less; The glass composition comprises, in mass %, [Table 4] Including, Regarding the glass rod.

[0146] In one embodiment, the present invention provides a method for producing a fluorophore having a length of l rod , average half-major axis length l major(a) , and the average semi-minor axis length l minor(a) A glass rod having a length l rod is 100 to 1600 mm, Within the cross section of the glass rod, l major(n) is the distance from the center of mass of the cross section to the farthest boundary of the glass rod within the cross section, and l minor(n) is the distance from the center of mass of the cross section to the nearest boundary of the glass rod within the cross section, and l major(n) and minor(n) can be the same or different from The glass rod is 10 4The glass composition has a T4 temperature of 1400°C or more, which is defined as the temperature at which the glass composition has a viscosity of 100 dPa·s, The average semi-major axis length l major(a) is 0.9 to 3.1 mm, and the semi-minor axis length l minor(n) is 0.9 to 3.1 mm, The semi-major axis length l major(n) is the average semi-major axis length l of the 50 equidistant cross-sectional positions major(a) and / or The semi-minor axis length l minor(n) is within a tolerance of 10%, 5%, or 2% at each equidistant position relative to the average semi-minor axis length of the 50 equidistant cross-sectional positions, The 50 equidistant sections are arranged along the length l of the glass rod. rod The initial position is 0.01×l. rod Starting at position l, and adding an additional increment of 0.02 x l for each successive position rod is used, The glass composition comprises, in mass %, [Table 5] Including, Regarding the glass rod.

[0147] In one embodiment, the present invention provides a method for producing a fluorophore having a length of l rod , average half-major axis length l major(a) , and the average semi-minor axis length l minor(a) A glass rod having a length l rod is 100 to 1600 mm, Within the cross section of the glass rod, l major(n) is the distance from the center of mass of the cross section to the farthest boundary of the glass rod within the cross section, and l minor(n) is the distance from the center of mass of the cross section to the farthest boundary of the glass rod within the cross section, and l major(n) and minor(n) can be the same or different from The glass rod is 10 4The glass composition has a T4 temperature of 1400°C or more, which is defined as the temperature at which the glass composition has a viscosity of 100 dPa·s, The glass rod has an average local ellipticity of 50 × (l major(n) -l minor(n) ) / (l major(n) +l minor(n) ) and has a mean ellipticity defined as the local ellipticity is sampled at 50 equidistant locations along the glass rod, and the average ellipticity is less than or equal to 0.20, less than 0.10, less than 0.050, or less than 0.030 at each equidistant location; The 50 equidistant sections are arranged along the length l of the glass rod. rod The initial position is 0.01×l. rod Starting at position l, and adding an additional increment of 0.02 x l for each successive position rod is used, The glass composition comprises, in mass %, [Table 6] Including, Regarding the glass rod.

[0148] In one embodiment, the present invention provides a method for producing a fluorophore having a length of l rod , average half-major axis length l major(a) , and the average semi-minor axis length l minor(a) A glass rod having a length l rod is 100 to 1600 mm, Within the cross section of the glass rod, l major(n) is the distance from the center of mass of the cross section to the farthest boundary of the glass rod within the cross section, and l minor(n) is the distance from the center of mass of the cross section to the nearest boundary of the glass rod within the cross section, and l major(n) and minor(n) can be the same or different from The glass rod is 10 4 The glass composition has a T4 temperature of 1400°C or more, which is defined as the temperature at which the glass composition has a viscosity of 100 dPa·s, Overall relative length variation of the semi-minor axis (tlv minor ) less than 0.040, TLV minor is determined as the absolute difference between the shortest and longest semi-minor axis lengths of the 50 equidistant cross-sectional locations, normalized by the average semi-minor axis length of the 50 equidistant cross-sectional locations; and / or has a relative overall area variation (tav) of less than 0.100, where tav is determined as the absolute difference between the smallest cross-sectional area at one cross-sectional location and the largest cross-sectional area of ​​said 50 equidistant cross-sectional locations, normalized by the average cross-sectional area of ​​said 50 equidistant cross-sectional locations; The 50 equidistant sections are arranged along the length l of the glass rod. rod The initial position is 0.01×l. rod Starting at position l, and adding an additional increment of 0.02 x l for each successive position rod is used, The glass composition comprises, in mass %, [Table 7] Including, Regarding the glass rod.

[0149] In one embodiment, the present invention provides a method for producing a fluorophore having a length of l rod , average half-major axis length l major(a) , and the average semi-minor axis length l minor(a) A glass rod having a length l rod is 100 to 1600 mm, Within the cross section of the glass rod, l major(n) is the distance from the center of mass of the cross section to the farthest boundary of the glass rod within the cross section, and l minor(n) is the distance from the center of mass of the cross section to the nearest boundary of the glass rod within the cross section, and l major(n) and minor(n) can be the same or different from The glass rod is 10 4 The glass composition has a T4 temperature of 1400°C or more, which is defined as the temperature at which the glass composition has a viscosity of 100 dPa·s, Overall relative length variation of the semimajor axis (tlv major ), relative local area variation (lav), and tlv major +lav, tlv major is determined as the absolute difference between (a) the shortest semi-major axis length of 50 equidistant cross-sectional locations and (b) the longest semi-major axis length of said 50 equidistant cross-sectional locations, and the average value l of the semi-major axis lengths of said 50 equidistant cross-sectional locations major(a) is normalized by The 50 equidistant sections are arranged along the length l of the glass rod. rod The initial position is 0.01×l. rod Starting at position l, and adding an additional increment of 0.02 x l for each successive position rod is used, lav is determined as (c) the absolute difference between the cross-sectional area at the cross-sectional location having the longest semi-major axis length of the 50 equidistant cross-sectional locations and (d) the average of the cross-sectional areas of the 50 equidistant cross-sectional locations, normalized by the average of the cross-sectional areas of the 50 equidistant cross-sectional locations; the quality index is 0.090 or less, 0.070 or less, or 0.050 or less; The average semi-major axis length l major(a) is 0.9 to 3.1 mm, and the average semi-minor axis length l minor(a) is 0.9 to 3.1 mm, The semi-major axis length l major(n) is the average semi-major axis length l of the 50 equidistant cross-sectional positions major(a) and / or The semi-minor axis length l minor(n) is within a tolerance of 10%, 5%, or 2% at each equidistant position relative to the average semi-minor axis length of the 50 equidistant cross-sectional positions, The glass composition comprises, in mass %, [Table 8] The present invention relates to the glass rod comprising:

[0150] In one embodiment, the present invention provides a method for producing a fluorophore having a length of l rod , average half-major axis length l major(a) , and the average semi-minor axis length l minor(a) A glass rod having a length l rod is 100 to 1600 mm, Within the cross section of the glass rod, l major(n) is the distance from the center of mass of the cross section to the farthest boundary of the glass rod within the cross section, and l minor(n) is the distance from the center of mass of the cross section to the nearest boundary of the glass rod within the cross section, and l major(n) and minor(n) can be the same or different from The glass rod is 10 4 The glass composition has a T4 temperature of 1400°C or more, which is defined as the temperature at which the glass composition has a viscosity of 100 dPa·s, Overall relative length variation of the semimajor axis (tlv major ), relative local area variation (lav), and tlv major +lav, tlv major is determined as the absolute difference between (a) the shortest semi-major axis length of 50 equidistant cross-sectional locations and (b) the longest semi-major axis length of said 50 equidistant cross-sectional locations, and the average value l of the semi-major axis lengths of said 50 equidistant cross-sectional locations major(a) is normalized by The 50 equidistant sections are arranged along the length l of the glass rod. rod The initial position is 0.01×l. rod Starting at position l, and adding an additional increment of 0.02 x l for each successive position rod is used, lav is determined as (c) the absolute difference between the cross-sectional area at the cross-sectional location having the longest semi-major axis length of the 50 equidistant cross-sectional locations and (d) the average of the cross-sectional areas of the 50 equidistant cross-sectional locations, normalized by the average of the cross-sectional areas of the 50 equidistant cross-sectional locations; the quality index is 0.090 or less, 0.070 or less, or 0.050 or less; The glass rod has an average local ellipticity of 50 × (l major(n) -l minor(n) ) / (l major(n) +l minor(n) ) and has a mean ellipticity defined as the local ellipticity is sampled at 50 equidistant locations along the glass rod, and the average ellipticity is less than or equal to 0.20, less than 0.10, less than 0.050, or less than 0.030 at each equidistant location; The glass composition comprises, in mass %, [Table 9] Including, Regarding the glass rod.

[0151] In one embodiment, the present invention provides a method for producing a fluorophore having a length of l rod , average half-major axis length l major(a) , and the average semi-minor axis length l minor(a) A glass rod having a length l rod is 100 to 1600 mm, Within the cross section of the glass rod, l major(n) is the distance from the center of mass of the cross section to the farthest boundary of the glass rod within the cross section, and l minor(n) is the distance from the center of mass of the cross section to the nearest boundary of the glass rod within the cross section, and l major(n) and minor(n) can be the same or different from The glass rod is 10 4 The glass composition has a T4 temperature of 1400°C or more, which is defined as the temperature at which the glass composition has a viscosity of 100 dPa·s, Overall relative length variation of the semimajor axis (tlv major ), relative local area variation (lav), and tlv major +lav, tlv majoris determined as the absolute difference between (a) the shortest semi-major axis length of 50 equidistant cross-sectional locations and (b) the longest semi-major axis length of said 50 equidistant cross-sectional locations, and the average value l of the semi-major axis lengths of said 50 equidistant cross-sectional locations major(a) is normalized by The 50 equidistant sections are arranged along the length l of the glass rod. rod The initial position is 0.01×l. rod Starting at position l, and adding an additional increment of 0.02 x l for each successive position rod is used, lav is determined as (c) the absolute difference between the cross-sectional area at the cross-sectional location having the longest semi-major axis length of the 50 equidistant cross-sectional locations and (d) the average of the cross-sectional areas of the 50 equidistant cross-sectional locations, normalized by the average of the cross-sectional areas of the 50 equidistant cross-sectional locations; the quality index is 0.090 or less, 0.070 or less, or 0.050 or less; The glass rod has a total relative length variation of the semi-minor axis (tlv minor ) less than 0.040, TLV minor is determined as the absolute difference between the shortest and longest semi-minor axis lengths of the 50 equidistant cross-sectional locations, normalized by the average semi-minor axis length of the 50 equidistant cross-sectional locations; and / or has a relative overall area variation (tav) of less than 0.100, where tav is determined as the absolute difference between the smallest cross-sectional area at one cross-sectional location and the largest cross-sectional area of ​​said 50 equidistant cross-sectional locations, normalized by the average cross-sectional area of ​​said 50 equidistant cross-sectional locations; The glass composition comprises, in mass %, [Table 10] Including, Regarding the glass rod. [Brief description of the drawings]

[0152] [Figure 1]FIG. 1 shows a schematic diagram of a glass rod in perspective (A) and in cross section n (B) showing relevant geometrical features. The glass rod has a length lrod and is approximately the shape of a right circular cylinder with an approximate circular base. Fifty equidistant cross sections are placed (cs1-cs50) along the length lrod of the glass rod, starting at a position (cs1) of 0.01×lrod as the first position, and using additional increments of 0.02×lrod for each successive position (csn). The 50 equidistant cross sections are parallel to the approximate circular base. Each of the 50 equidistant cross sections csn has a semimajor axis length lmajor(n) and a semiminor axis length lminor(n), a center of mass cm, and a local area. From the 50 equidistant cross sections, the average semimajor axis length lmajor(a) and the average semiminor axis length lminor(a) can be calculated as the average of the 50 semimajor axis length lmajor(n) values ​​and the average of the 50 semiminor axis length lminor(n) values, respectively. [Diagram 2] 2 shows the quality indexes for glass rods according to the present invention (Inventive Examples 1 to 7, IE1 to IE7) compared with glass rods according to the prior art (Comparative Examples 1 to 4, CE1 to CE4). The glass compositions used in the inventive examples are shown in brackets. [Diagram 3] 3 shows the parameters tlvmajor and lav for glass rods according to the invention (Inventive Examples 1-7, IE1-IE7) in comparison with glass rods according to the prior art (Comparative Examples 1-4, CE1-CE4). The glass compositions used in the inventive examples are indicated in brackets. [Figure 4] 4 shows the parameter tlvminor for glass rods according to the invention (Inventive Examples 1-7, IE1-IE7) in comparison with glass rods according to the prior art (Comparative Examples 1-4, CE1-CE4). The glass compositions used in the inventive examples are shown in brackets. [Diagram 5] 5 shows the parameter tav for glass rods according to the invention (Inventive Examples 1 to 7, IE1 to IE7) in comparison with glass rods according to the prior art (Comparative Examples 1 to 4, CE1 to CE4). The glass compositions used in the inventive examples are shown in brackets. [Figure 6]FIG. 6 shows a diagram of the method and reactor according to the invention. The reactor (1) has a lower discharge opening (2). Glass raw materials are heated in the reactor (1) to obtain a glass melt (3). A conveying means (4) assists the withdrawal of a glass rod (5) downstream of the reactor, i.e. after the glass melt (3) leaves the reactor (1) through the lower discharge opening (2). The lower discharge opening (2) is heated independently (e.g. by an electromagnetic coil shown as a circle) to ensure a constant and homogenous glass flow. The lower discharge opening (2) can be a nozzle or a duct. The withdrawal temperature of the glass melt (3) is measured using an IR pyrometer (6). The pressure above the glass melt is measured using a pressure sensor (7). EXAMPLES

[0153] Measurement of geometric parameters The comparative glass rods and the glasses according to the invention were measured with a sliding caliper to evaluate their geometrical properties, such as the maximum diameter measurable in the cross section and the minimum diameter measurable in the cross section. The measurement uncertainty was about 50 μm.

[0154] Four comparative glass rods with a length of 30 cm were measured at a distance of 5 mm. A glass rod according to the invention with a length of 100 cm was measured at a distance of 2 cm. Graphical analysis further provided the ellipticity and cross-sectional area for each cross section over the lengths of 30 cm and 100 cm, respectively.

[0155] Glass composition Glass rods according to the invention were made from five different glass compositions having thermal expansion coefficients of 1.25, 1.60, 1.90, 2.65 and 3.05 ppm / K, respectively.

[0156] [Table 11]

[0157] Glass rod manufacturing To produce the glass rods, a small hot gas-fired glass tank furnace was used, as described in Journal of the Society of Glass Technology 28, 1944, pages 105-112. The tank furnace has internal dimensions of 21 inches long, 12 inches wide, and 13 inches high. The glass depth at the start of production is about 4-5 inches. The furnace lining consisted of blocks molded from a mixture of zircon sand and zirconia, using starch glue as a temporary bond. The drawing temperature of the glass melt was measured above the glass melt by an IR pyrometer, in the center of the reactor, monitoring the glass surface via IR radiation. The pressure above the glass melt was measured by a pressure sensor. During production, the glass rods being drawn were measured, i.e., their outer diameters and their local areas. The rate at which the glass melt was drawn, or the volumetric flow rate, was continuously monitored. During production, the temperature and pressure of the glass melt were manually regulated to ensure a constant and homogenous glass flow. Before the start of the draw, the glass melt was at least partially heated to a temperature T2.5 and then increased in 1°C increments. The temperature increase during the draw was a maximum of 50°C, typically about 30°C. The production temperature was controlled and regulated both in the reactor and at the lower discharge opening. Alternatively or additionally, the pressure in the furnace, i.e. above the glass melt, was regulated, taking into account the pressure drop at the discharge opening head due to the drop in the glass melt level during the draw. The production took place over a period of typically 4 hours.

Claims

1. length l rod , average half-major axis length l major(a) , and average semi-minor axis length l minor(a) A glass rod having the length l rod The range is 100 to 1600 mm. Within the cross-section of the glass rod, l major(n) l is the distance from the center of mass of the cross-section to the furthest boundary of the glass rod within the cross-section, and l minor(n) l is the distance from the center of mass of the cross-section to the nearest boundary of the glass rod within the cross-section. major(n) and l minor(n) It can be the same as or different from, The glass rod contains a glass composition having a T4 temperature of 1400 °C or higher, which is defined as the temperature at which the glass has a viscosity of 10 4 dPa·s, The glass rod has a variation in the overall relative length of its semi-long axis (tlv major ), relative local area variability (lav), and tlv major It has a quality index defined as the sum of +lav, thlv major (a) The shortest semi-major axis length l of the equidistant cross-sectional positions of 50 major(n) (b) the longest semi-major axis length l of the equidistant cross-sectional positions of the 50 major(n) It is identified as the absolute difference between and the average value l of the semi-major axis lengths of the equidistant cross-sectional positions of 50. major(a) Normalized by, The equidistant cross-sections of the 50 are the length l of the glass rod. rod It is positioned along and the initial position is 0.01 × l rod Starting at position and adding an additional increment of 0.02 × l for each subsequent position rod This is used, Lav is defined as the absolute difference between (c) the cross-sectional area at the cross-sectional position having the longest semi-major axis length among the equidistant cross-sectional positions of 50 and (d) the average value of the cross-sectional areas at the equidistant cross-sectional positions of 50, and is normalized by the average value of the cross-sectional areas at the equidistant cross-sectional positions of 50. The aforementioned quality index is 0.090 or less, 0.070 or less, or 0.050 or less. The aforementioned glass rod.

2. The average semi-major axis length l major(a) The length is 0.9 to 3.1 mm, and the average semi-short axis length l minor(a) The size is 0.9 to 3.1 mm. The aforementioned semi-major axis length l major(n) The tolerances for the average semi-major axis length at each equidistant cross-sectional position of 50 are within 10%, 5%, or 2%, and / or The semi-minor axis length l minor(n) The tolerances for the average semi-short axis length at equidistant cross-sectional positions of the 50 are within 10%, 5%, or 2% at each equidistant position. The glass rod according to claim 1.

3. The glass rod according to claim 1, wherein the curvature or bending is 0.030 to 0.30 mm, measured in accordance with DIN EN ISO 1101:2017-09 and at a support distance of 300 mm.

4. The average of 2 × (l) local ellipticity of 50 major(n) -l minor(n) ) / ( l major(n) +l minor(n) The glass rod according to claim 1, having an average ellipticity defined as ), wherein the average ellipticity is sampled at equidistant positions of 50 along the glass rod, and the average ellipticity at each equidistant position is 0.20 or less, less than 0.10, less than 0.050, or less than 0.

030.

5. Variation in the overall relative length of the semi-minor axis (tlv minor ) has less than 0.040 and tlv minor This is defined as the absolute difference between the shortest and longest semi-short axis lengths of the equidistant cross-sectional positions of 50, normalized by the average value of the semi-short axis lengths of the equidistant cross-sectional positions of 50, and / or The relative overall area variation (tav) is less than 0.100, where tav is defined as the absolute difference between the minimum cross-sectional area at one cross-sectional location and the maximum cross-sectional area at the equidistant cross-sectional locations of the 50, and is normalized by the average value of the cross-sectional areas at the equidistant cross-sectional locations of the 50. The glass rod according to claim 1.

6. One or more of the following characteristics: - The number of bubbles in the glass rod is less than 10, less than 5, or less than 2, and the length of the bubbles is measured as the longest straight-line distance in the bubbles and is at least 0.5 mm. - The length of the bubble, as measured as the longest straight-line distance in the bubble, is less than 70 mm, less than 50 mm, or less than 10 mm, and - There is no bubble expansion exceeding 100 mm, where bubble expansion is defined as the generation of a series of bubbles arranged sequentially along the length of the glass rod, and the distance between two adjacent bubbles is shorter than the length of the longest bubble in the sequence. A glass rod according to claim 1, characterized by the above.

7. The glass composition contains, by mass percentage, one or more or all of the following components: 70.0% to 90.0% SiO 2 , ・ 0.0% to 25.0% B 2 O 3 , 0.0% to 10.0% Al 2 O 3 , - 0.0% to 10.0% of one or more alkaline earth metal oxides, - 0.0% to 7.0% of one or more alkali metal oxides A glass rod according to claim 1, including the glass rod described in claim 1.

8. A set of glass rods comprising at least 40 glass rods as described in any one of claims 1 to 7.

9. At least 80% of the glass rods have one or more of the following characteristics: Preferably, there are no bubbles defined as longitudinal voids completely enclosed within the glass rod, formed by gas inclusions in the glass, where the gas may be gaseous at 20°C and / or may condense after cooling, and bubbles with reduced pressure are formed, having a diameter of 0.15 mm or less at the longest extent of the longitudinal void in the cross-sectional direction of the glass rod, and having a length of 50 mm or less along the longest extent of the glass rod. - Open bubbles are essentially absent, where the length of the bubbles is at least 0.5 mm, measured as the longest straight-line distance in the bubbles, and - Absence of inclusions defined as foreign matter completely enclosed within the glass rod having a size of 100 μm or more, preferably metallic particle inclusions and / or non-metallic particle inclusions. A set of glass rods according to claim 8, comprising:

10. A method for manufacturing a glass rod, optionally according to any one of claims 1 to 7, comprising the following steps: - The step of preparing the reactor (1) including the lower discharge opening (2), - A step in which glass raw materials are heated in the reactor to obtain a glass molten product (3), - At least partially of the molten glass, the molten glass is 10 2.5 The step of heating to a temperature T2.5 defined as the temperature at which the viscosity is dPa·s, - A step of withdrawing the molten glass from the reactor at the withdrawal temperature and the withdrawal speed of the molten glass, - A step of controlling the extraction speed of the molten glass by increasing the extraction temperature and / or adjusting the pressure on the molten glass, - The step of cooling and / or shaping the molten glass to obtain a glass rod (5), and / or obtaining the glass rod (5) according to any one of claims 1 to 7. The glass composition comprises a glass molten material having a T4 temperature of 1400°C or higher, where T4 is the temperature of the glass molten composition. 4 The method, wherein the temperature is such that the viscosity is dPa·s.

11. One or more of the following conditions: - The glass molten material (3) is withdrawn at a withdrawal temperature at least 50°C above T4, preferably 50 to 130°C above T4, with a tolerance of 10°C, 5°C, or 3°C, where preferably the withdrawal of the glass molten material from the reactor (1) is carried out through the discharge opening (2). - Increase the extraction temperature to control the extraction speed of the molten glass to a tolerance of 2% or less, or 1% or less, and - The pressure on the molten glass is adjusted to control the extraction speed of the molten glass to a tolerance of 2% or less, or 1% or less. The method according to claim 10, wherein the condition is met.

12. The method according to claim 10, wherein the withdrawal of the molten glass from the reactor (1) is at a rate of 2 to 50 m / min with respect to the length of the glass rod (5) exiting the lower discharge opening (2), and / or the molten glass (3) is withdrawn from the reactor (1) at a volumetric flow rate of 15 to 150 ml / min.

13. The method according to claim 10, further comprising the step of interrupting the withdrawal of the glass molten material (3) from a reactor (1), which is preferably operated as a batch reactor, before the consumption of 90%, 80%, 70%, 60%, or 50% of the glass molten material is reached.

14. The following stages: - When 90% of the glass molten material has been consumed, the process continues to withdraw the glass molten material (3) from the reactor (1), which is preferably operated as a batch reactor, and - The step of heating the molten surface. The method according to claim 10, further comprising the heating of the molten surface resulting in the withdrawal of the glass molten material from the reactor (1) at a rate of 1% or less tolerance and / or at a volumetric flow rate of 1% or less tolerance.

15. Adjusting the pressure above the molten glass can be done by one or more of the following means: - To hermetically seal the reactor, and - Compensate for the pressure drop at the lower discharge opening using compressed air. The method according to claim 10, including the method described in claim 10.

16. The above method, exhaust gas, for example, CO 2 To eliminate this, the process is carried out under heating by electrical means only, and / or the contact surface of the reactor in contact with the glass molten material contains more than 70% by mass of ZrO 2 The method according to claim 10, comprising 30% by mass or more of a contact material in the form of cast zirconia, and / or the contact surface of the reactor in contact with the glass molten material comprises a sintered material having more than 80% by mass, more than 90% by mass, or more than 95% by mass of zirconium silicate.

17. The glass rod according to any one of claims 1 to 7, wherein the glass has a water content of at least 35 mmol / l, preferably at least 45 mmol / l, more preferably at least 55 mmol / l, and / or the glass has a coefficient of thermal expansion of 0.8 ppm / K to 4.5 ppm / K in a temperature range of 20°C to 300°C.

18. A flash lamp comprising a glass rod according to any one of claims 1 to 7, wherein the flash lamp further comprises a tungsten or molybdenum electrode and a quartz glass, the glass sealing the quartz glass to the tungsten or molybdenum electrode.

19. Use of a glass rod according to any one of claims 1 to 7 for joining a metal article to a glass member and / or for a flash lamp.

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