Glass tube with dome-shaped end

Abstract

A glass tube comprising a first end and a second end, and a hollow cylindrical side wall having an outer diameter d1, wherein the first end, the second end, or both are provided with a dome end glaze, the dome end glaze being made of glass and having a convex outer surface. A method for finishing the end of a glass tube comprises rotating the glass tube around its central axis, simultaneously forming a glass meniscus on a new end of the glass tube while removing an annular segment of the glass tube from a starting end of the glass tube, and polishing the glass meniscus at the new end of the glass tube to form a dome end glaze at the new end of the glass tube, the dome end glaze having a convex outer surface.

Description

[Technical Field]

[0001] Cross-reference of related applications This application claims the benefit of priority under § 119 of U.S. Patent Act pursuant to U.S. Provisional Application No. 63 / 470,230, filed on 1 June 2023, the contents of which this Provisional Application is relied upon and incorporated in its entirety by reference herein.

[0002] This specification relates, in general, to glass tubes, and more specifically to glass tubes having dome-shaped ends and methods for manufacturing the same. [Background technology]

[0003] Historically, glass has been used to produce a variety of articles. For example, due to its airtightness, optical clarity, and superior chemical durability compared to other materials, glass is a preferred material for pharmaceutical applications, including but not limited to vials, syringes, ampoules, cartridges, and other glass articles. Producing these articles from glass begins with providing glass tubular material that can be later formed and separated into multiple glass articles. Specifically, glass used in pharmaceutical packaging must have adequate mechanical and chemical durability so as not to affect the stability of the pharmaceutical formulation contained therein. Glass with suitable chemical durability includes those glass compositions within the ASTM standard "Type IA" and "Type IB" glass compositions, which have a proven track record of chemical durability.

[0004] The glass tubes used as starting materials for producing glass articles are produced from continuous processes such as the Danner or Vello processes for producing continuous hollow glass cylinders. The continuous hollow glass cylinder is annealed and cut by a high-speed continuous cutter into sections of glass tubes of substantially the same length. After initially separating the continuous hollow glass cylinder into a plurality of glass tubes, each of the glass tubes is further processed to finish the ends of the glass tubes, such as by cutting to length and polishing the ends to reduce breakage during shipping and handling. The processing operations involved in finishing the ends of the glass tubes can introduce defects into the glass tubes. Summary of the Invention

[0005] According to a first aspect of the present disclosure, a glass tube may comprise a first end and a second end, and a hollow cylindrical sidewall comprising glass and having an outer diameter d1. The first end, the second end, or both may comprise a dome end glaze, and the dome end glaze comprises glass and has a convex outer surface. The glass tube may have a longitudinal length L that is 30 times or more of d1.

[0006] A second aspect may include the first aspect, and the longitudinal length L of the glass tube is 800 mm or more.

[0007] A third aspect may include any one of the first or second aspects, and the convex shape of the outer surface of the dome end glaze has a radius of curvature r that is 0.4 times or more of d1 over a position on the convex shape within a distance of 0.4 times of d1 from the central axis of the glass tube. c comprises.

[0008] A fourth aspect may include the third aspect, and the radius of curvature is 0.6 times or less of d1 over a position on the convex shape within a distance of 0.4 times of d1 from the central axis of the glass tube.

[0009] A fifth aspect may include any one of the first or second aspects, and the dome end glaze has a dome height H that is 0.4 times or more of d1.

[0010] The sixth embodiment may include the fifth embodiment, where the dome height H is 0.6 times d1 or less.

[0011] The seventh embodiment may include any one of the first to sixth embodiments, wherein the dome end glaze has a wall thickness that is less than or equal to the wall thickness of the hollow cylindrical side wall.

[0012] The eighth embodiment may include any one of the first to seventh embodiments, wherein the dome end glaze covers at least 75% of the cross-sectional area of ​​the glass tube at the first end, the second end, or both.

[0013] The ninth embodiment may include the eighth embodiment, wherein the dome end glaze closes the glass tube at the first end of the glass tube, the second end of the glass tube, or both.

[0014] The tenth embodiment may include the eighth embodiment, wherein the dome end glaze is provided with ventilation holes.

[0015] The eleventh embodiment may include the tenth embodiment, in which the vents are aligned with the central axis of the glass tube.

[0016] The twelfth embodiment may include the tenth embodiment, wherein the centerline of the vent hole is at an angle of less than 90 degrees, less than 70 degrees, or less than 45 degrees with respect to the central axis of the glass tube.

[0017] The 13th embodiment may include the 10th embodiment, wherein the centerline of the vent is not perpendicular to the central axis of the glass tube.

[0018] The 14th embodiment may include any one of the 10th to 13th embodiments, wherein the vents have a diameter of 0.05 to 0.20 times d1.

[0019] The 15th embodiment may include any one of the 1st to 14th embodiments, wherein the glass tube is substantially free of end cracks and inclusions.

[0020] The sixteenth embodiment may include any one of the first to fifteenth embodiments, wherein the glass tube substantially does not contain glass particles fused to the outer and inner surfaces of the hollow cylindrical sidewall.

[0021] The 17th embodiment may include any one of the 1st to 16th embodiments, wherein the dome end glaze comprises a first dome end glaze at a first end of the glass tube and a second dome end glaze at a second end of the glass tube.

[0022] According to a 18th aspect of the present disclosure, a method for finishing the end of a glass tube may include rotating the glass tube about a central axis of the glass tube, and removing an annular segment of the glass tube from the starting end of the glass tube, wherein removing the annular segment from the starting end of the glass tube may include removing a glass meniscus on the new end of the glass tube, and polishing the glass meniscus at the new end of the glass tube to form a dome end glaze at the new end of the glass tube, the dome end glaze having a convex outer surface. The glass tube may have a longitudinal length L of 30 times or more d1, where d1 is the outer diameter of the glass tube.

[0023] The 19th embodiment may include the 18th embodiment, wherein the longitudinal length L of the glass tube is 800 mm or more.

[0024] The 20th aspect may include either the 18th or 19th aspect, wherein the convex shape on the outer surface of the dome end glaze has a radius of curvature r of 0.4 times d1 or more over a position on the convex shape that is at a distance of 0.4 times d1 from the central axis of the glass tube. c It is equipped with.

[0025] The 21st aspect may include the 20th aspect, with a radius of curvature r c The value is less than or equal to 0.6 times d1 over positions on the convex shape that are at a distance of 0.4 times d1 from the central axis of the glass tube.

[0026] The 22nd aspect may include either the 18th or 19th aspect, wherein the dome end glaze has a dome height H of 0.4 times d1 or more.

[0027] The 23rd embodiment may include the 22nd embodiment, where the dome height H is 0.6 times d1 or less.

[0028] The 24th embodiment may include any one of the 18th to 23rd embodiments, wherein removing an annular segment from the starting end of a glass tube includes heating a target region of the glass tube adjacent to the starting end of the glass tube, and transporting the annular segment of the glass tube away from the glass tube in a direction parallel to the central axis of the glass tube.

[0029] The 25th embodiment may include the 24th embodiment, wherein heating the target region of the glass tube includes heating the glass tube in the circumferential direction as the glass tube rotates, and the target region is 50 mm or less from the starting end of the glass tube.

[0030] The 26th embodiment may include either the 24th or 25th embodiment, wherein transporting an annular segment of a glass tube away from the glass tube includes bringing the starting end of the glass tube into contact with a roller having a roller rotation axis at an angle of 10 to 80 degrees with the central axis of the glass tube, and bringing the starting end of the glass tube into contact with the roller exerts an axial tensile force on the starting end of the glass tube, the axial tensile force separating the annular segment from the glass tube.

[0031] The 27th aspect may include any one of the 18th to 26th aspects, wherein polishing the glass meniscus at a new end of the glass tube includes flame polishing the glass meniscus at a new end of the glass tube by exposing it to a gas burner.

[0032] The 28th embodiment may include any one of the 18th to 27th embodiments, wherein finishing the end of the glass tube produces a glass tube that is substantially free of end cracks and inclusions.

[0033] The 29th embodiment may include any one of the 18th to 28th embodiments, wherein finishing the end of the glass tube produces a glass tube that is substantially free of glass particles fused to the outer or inner surface of the glass tube.

[0034] The 30th aspect may include any one of the 18th to 29th aspects, further comprising forming ventilation holes in the dome end glaze.

[0035] The 31st aspect may include the 30th aspect, wherein forming a vent in the dome end glaze includes opening the dome end glaze at a position aligned with the central axis of the glass tube.

[0036] The 32nd aspect may include either the 30th or 31st aspect, wherein forming a vent in the dome end glaze includes exposing the dome end glaze to a vent burner to melt and open the dome end glaze.

[0037] The 33rd aspect may include any one of the 18th to 32nd aspects, further comprising forming a meniscus to modify the convex shape of the dome end glaze.

[0038] The 34th aspect may include the 33rd aspect, wherein forming a meniscus involves bringing the meniscus into contact with a forming tool for reshaping the meniscus.

[0039] The 35th aspect may include any one of the 18th to 34th aspects, the method of removing a first annular segment of a glass tube from a first starting end of the glass tube, the removal of the first annular segment from the first starting end of the glass tube, the removal of the first annular segment from the first starting end of the glass tube, the removal of a first glass meniscus on a first new end of the glass tube, the polishing of the first glass meniscus and the first new end of the glass tube to form a first dome end glaze at the first new end of the glass tube, and the removal of a second annular segment of the glass tube from a second starting end of the glass tube. The process involves removing a second annular segment from a second starting end of the glass tube to form a second glass meniscus on a second new end of the glass tube, and finishing the first and second ends of the glass tube by polishing the second glass meniscus and the second new end of the glass tube to form a second dome end glaze at the second new end of the glass tube, wherein the first dome end glaze comprises a first outer surface having a first convex shape, and the second dome end glaze comprises a second outer surface having a second convex shape.

[0040] The 36th aspect may include any one of the 18th to 35th aspects, further comprising forming a meniscus to modify the convex shape of the dome end glaze.

[0041] According to a 37th aspect of the present disclosure, a system for finishing the end of a glass tube may include: a conveyor configured to translate the glass tube and rotate the glass tube about a central axis of the glass tube, the glass tube having a longitudinal length L of 30 times or more d1, where d1 is the outer diameter of the glass tube; a separation station configured to remove an annular segment of the glass tube from the starting end of the glass tube, the separation station comprising removing the annular segment from the starting end of the glass tube to form a glass meniscus on a new end of the glass tube; and a polishing station configured to form a glass meniscus at a new end of the glass tube to form a dome end glaze at the new end of the glass tube, the polishing station comprising a conveyor configured to translate the glass tube and rotate the glass tube about a central axis of the glass tube, the glass tube having a longitudinal length L of 30 times or more d1, where d1 is the outer diameter of the glass tube.

[0042] The 38th embodiment may include the 37th embodiment, wherein the conveyor comprises a plurality of transport rollers configured to translate the glass tube in a direction perpendicular to the central axis of the glass tube.

[0043] The 39th aspect may include either the 37th or 38th aspect, wherein the convex shape on the outer surface of the dome end glaze has a radius of curvature r of 0.4 times d1 or more over a position on the convex shape that is at a distance of 0.4 times d1 from the central axis of the glass tube. c It is equipped with.

[0044] The 40th aspect may include the 39th aspect, with a radius of curvature r c The value is less than or equal to 0.6 times d1 over positions on the convex shape that are at a distance of 0.4 times d1 from the central axis of the glass tube.

[0045] The 41st aspect may include either the 37th or 38th aspect, wherein the dome end glaze has a dome height H of 0.4 times d1 or more.

[0046] The 42nd embodiment may include the 42nd embodiment, where the dome height H is 0.6 times or less of d1.

[0047] The 43rd embodiment may include any one of the 37th to 42nd embodiments, wherein the separation station comprises one or more preheating stations configured to heat a target region of the glass tube adjacent to the starting end of the glass tube, and a pulling station configured to transport an annular segment of the glass tube away from the glass tube in a direction parallel to the central axis of the glass tube.

[0048] The 44th embodiment may include the 43rd embodiment, each of which one or more preheating stations comprises a gas burner configured to heat a target area of ​​the glass tube circumferentially as the glass tube rotates.

[0049] The 45th embodiment may include either the 43rd or 44th embodiment, wherein the target area is 50 mm or less from the starting end of the glass tube.

[0050] The 46th embodiment may include any one of the 43rd to 45th embodiments, wherein the pulling station comprises an end support roller configured to support the starting end of a glass tube, and a separating roller configured to exert an axial pulling force on the starting end of the glass tube, the axial pulling force separating an annular segment from the glass tube.

[0051] The 47th embodiment may include the 46th embodiment, wherein the separating roller has a roller rotation axis that forms an angle of 10 to 80 degrees with respect to the central axis of the glass tube.

[0052] The 48th embodiment may include any one of the 37th to 47th embodiments, wherein the polishing station comprises a gas burner configured to flame polish the glass meniscus at a new end of the glass tube.

[0053] The 49th embodiment may include any one of the 37th to 48th embodiments and is configured to finish the end of the glass tube such that the glass tube is substantially free of end cracks and inclusions.

[0054] The 50th embodiment may include any one of the 37th to 49th embodiments, wherein the glass tube is configured such that the end of the glass tube is finished so as to be substantially free of glass particles fused to the outer or inner surface of the glass tube.

[0055] The 51st embodiment may include any one of the 37th to 50th embodiments and further comprises a ventilation station configured to form ventilation holes in the dome end glaze.

[0056] The 52nd embodiment may include the 51st embodiment, wherein the vent station comprises a vent burner configured to melt and open the dome end glaze to form a vent.

[0057] The 53rd embodiment may include any one of the 37th to 52nd embodiments and further comprises a forming station configured to modify the convex shape of the dome end glaze.

[0058] The 54th embodiment may include the 53rd embodiment, wherein the forming station comprises a forming tool configured to reshape the meniscus.

[0059] The 55th aspect may include any one of the 37th to 54th aspects, wherein the separation station removes a first annular segment of the glass tube from a first starting end of the glass tube, the removal of the first annular segment from the first starting end of the glass tube forming a first glass meniscus on the first new end of the glass tube; and removes a second annular segment of the glass tube from a second starting end of the glass tube, the removal of the second annular segment from the second starting end of the glass tube forming a second glass meniscus on the second new end of the glass tube. The polishing station is configured to perform the following: polishing the first glass meniscus and the first new end of the glass tube in order to form a first dome end glaze at the first new end of the glass tube; and polishing the second glass meniscus and the second new end of the glass tube in order to form a second dome end glaze at the second new end of the glass tube, wherein the first dome end glaze has a first outer surface having a first convex shape, and the second dome end glaze has a second outer surface having a second convex shape.

[0060] The 56th embodiment may include any one of the 37th to 55th embodiments, wherein the conveyor is configured to receive glass tubes from a tube manufacturing process.

[0061] The 57th embodiment may include any one of the 37th to 56th embodiments, and the longitudinal length L of the glass tube is 800 mm or more.

[0062] Additional features and advantages of the systems and methods disclosed herein are described in the following detailed description and will be readily apparent to those skilled in the art from that description, or will be recognized by practicing the embodiments described herein, including the following detailed description, claims, and accompanying drawings.

[0063] It should be understood that both the above-mentioned overview and the following embodiments for carrying out the invention are intended to describe various embodiments and to provide an overview or framework for understanding the nature and features of the claimed subject matter. The accompanying drawings are included to provide a further understanding of the various embodiments and are incorporated herein and constitute part of this specification. The drawings illustrate the various embodiments described herein and, together with the descriptions, help to illustrate the principles and operation of the claimed subject matter. [Brief explanation of the drawing]

[0064] [Figure 1] A schematic cross-sectional view of a glass tube according to one or more embodiments shown and described herein is shown. [Figure 2] This specification schematically illustrates a system for finishing one or both ends of a glass tube, according to one or more embodiments shown and described herein. [Figure 3] A schematic cross-sectional view of another embodiment of the glass tube, according to one or more embodiments shown and described herein, is shown. [Figure 4] A schematic cross-sectional view of another embodiment of the glass tube, according to one or more embodiments shown and described herein, is shown. [Figure 5] A schematic cross-sectional view of another embodiment of the glass tube, according to one or more embodiments shown and described herein, is shown. [Figure 6A] A schematic top view of a glass tube having a vent, according to one or more embodiments shown and described herein, is shown. [Figure 6B] A schematic cross-sectional side view of the glass tube in Figure 6A is shown according to one or more embodiments described herein. [Figure 7] A schematic cross-sectional view of another embodiment of a glass tube having a vent, according to one or more embodiments shown and described herein, is shown. [Figure 8] A schematic top view is shown of a process for the continuous production of glass tubes according to one or more embodiments described herein. [Figure 9] A schematic side view of the process shown in Figure 8 for the continuous production of glass tubes according to one or more embodiments described herein. [Figure 10] A schematic diagram of the conveyor system of Figure 1, according to one or more embodiments shown and described herein, is shown. [Figure 11] A schematic diagram of the preheating station of the system in Figure 1, according to one or more embodiments shown and described herein, is shown. [Figure 12A] A schematic representation of the tension station of the system shown in Figure 1, according to one or more embodiments described herein, is shown. [Figure 12B] A schematic diagram of the tension station of the system shown in Figure 12A after the annular segment of the glass tube has been separated from the glass tube, according to one or more embodiments shown and described herein. [Figure 13A] Another embodiment of the tension station of the system in Figure 1, according to one or more embodiments shown and described herein, is schematically shown. [Figure 13B] Figure 13A schematically shows the tension station of the system after the annular segment of the glass tube has been separated from the glass tube, according to one or more embodiments shown and described herein. [Figure 14] A schematic diagram of the polishing station of the system shown in Figure 1, according to one or more embodiments described herein, is shown. [Figure 15] A schematic diagram of the ventilation station of the system shown in Figure 1, according to one or more embodiments described herein, is shown. [Figure 16] A schematic representation of the forming station of the system shown in Figure 1, according to one or more embodiments described herein, is shown.

[0065] Herein, various embodiments are referred to in more detail, some of which are illustrated in the accompanying drawings. Wherever possible, the same reference numerals are used throughout the drawings to refer to the same or similar parts. [Modes for carrying out the invention]

[0066] Herein, embodiments of glass tubes having dome-shaped ends, as well as methods and systems for manufacturing them, are described in detail. Wherever possible, the same reference numerals are used throughout the drawings to refer to the same or similar parts. Referring here to Figure 1, the glass tube 10 of the present disclosure (shown in a cross-sectional view) comprises a hollow cylindrical side wall 12 having an outer diameter d1, an outer surface 14, an inner surface 16, a first end 17, a second end 18 opposite the first end 17 (Figure 2), and a dome end glaze 20 having a convex outer surface 24, which is made of glass. The dome end glaze 20 may be on the first end 17, the second end 18, or both. The glass tube 10 has a longitudinal length L (Figure 2) of 30 times d1 or more.

[0067] Referring here to Figure 2, the system 100 of the present disclosure for finishing one or both ends of a glass tube 10 may include a conveyor 110 which is operable to translate the glass tube 10 horizontally and, at the same time, rotate each of the glass tubes 10 around the central axis A of each glass tube 10. The system 100 further includes a separation station 120 configured to remove annular segments 30 of each glass tube 10 from the starting end 32 of the glass tube 10, and removing the annular segments 30 from the starting end 32 of the glass tube 10 forms a glass meniscus 21 on the new end 34 of the glass tube 10. The system 100 may further include a polishing station 130 configured to form a glass meniscus 21 on the new end 34 of the glass tube 10 in order to form a dome end glaze 20 on the new end 34 of the glass tube 10, the dome end glaze 20 having a convex outer surface 24. The longitudinal length L of the glass tube 10 may be 30 times or more d1. Note that various gas burners and other processing equipment are not shown in system 100 schematicly in Figure 2. The conveyor 110 is schematicly shown in Figure 10 using gas burners and other processing equipment.

[0068] The system 100 disclosed herein can be used in a method for finishing one or both ends of a glass tube 10. A method disclosed herein for finishing one or more ends of a glass tube 10 includes rotating the glass tube 10 about a central axis A and removing an annular segment 30 of the glass tube 10 from a starting end 32, wherein removing the annular segment 30 from the starting end 32 of the glass tube 10 forms a glass meniscus 21 on a new end 34 of the glass tube 10, and polishing the glass meniscus 21 at the new end 34 of the glass tube 10 to form a dome end glaze 20 at the new end 34 of the glass tube 10. Furthermore, a method disclosed herein for finishing one or both ends of a glass tube 10 can be used to produce a glass tube 10 having a longitudinal length L which may be 30 times or more d1.

[0069] Unless otherwise specified, no method described herein is intended to be construed as requiring its steps to be performed in a specific order, nor as requiring any particular orientation in any apparatus. Therefore, if a method claim does not actually list the order in which its steps should be followed, or if any apparatus claim does not actually list an order or orientation for its individual components, or if it is not otherwise specifically stated in the claim or specification that the steps should be limited to a specific order, or if no specific order or orientation for the components of the apparatus is listed, no order or orientation is intended to be inferred in any sense. This includes all possible implicit grounds for interpretation, including logical matters relating to the arrangement of steps, the flow of operation, the order of components, or the orientation of components, the plain meaning derived from grammatical organization or punctuation, and the number or type of embodiments described herein.

[0070] The directional terms used herein, such as up, down, right, left, front, back, top, and bottom, are defined solely by reference to the drawings and are not intended to imply absolute orientation.

[0071] As used herein, the singular forms "a," "an," and "the" include plural referents unless the context clearly indicates otherwise. Therefore, for example, a reference to a certain "a" component includes embodiments having two or more such components unless the context explicitly indicates otherwise.

[0072] Where used herein, the term “approximately” means that quantities, sizes, formulations, parameters, and other quantities and characteristics are not and do not need to be exact, and are, as desired, approximate and / or may be greater or less, taking into account tolerances, conversion factors, rounding, measurement errors, and other factors known to those skilled in the art. Where the term “approximately” is used when describing values ​​or endpoints of a range, this disclosure should be understood to include the specific values ​​or endpoints being referenced. Whether or not the numerical values ​​or endpoints of a range in the specification indicate “approximately,” the numerical values ​​or endpoints of a range are intended to include two embodiments: those modified by “approximately” and those not modified by “approximately.” It will be further understood that each endpoint of a range is significant, whether in relation to other endpoints or independently of other endpoints.

[0073] As used herein, “axial direction” refers to the direction parallel to the central axis A of the glass tube.

[0074] As used herein, the terms “upstream” and “downstream” refer to the location of a feature of a glass tube in the manufacturing process relative to the direction of travel of the glass tube through the manufacturing process. For example, if a glass tube encounters a first feature before encountering a second feature, the first feature is “upstream” of the second feature. Conversely, if a glass tube encounters a second feature before encountering a first feature, the first feature is “downstream” of the second feature.

[0075] As used herein, the term "curvature" refers to the degree to which a curved surface deviates from a plane. It should be understood that "curvature" and "radius of curvature" are inversely correlated, meaning that as the radius of curvature decreases, the curvature of the surface increases.

[0076] Due to its airtightness, optical clarity, and superior chemical durability compared to other materials, glass is a preferred material for pharmaceutical applications, including but not limited to vials, syringes, ampoules, cartridges, bottles, and other glass articles. These pharmaceutical glass containers, and other types of glass articles, can be produced through a process that converts a glass tube into one or more glass articles through multiple heating and forming operations.

[0077] In the glass packaging industry, particularly in the glass pharmaceutical packaging industry, damage to tubing during shipping and handling is a root cause of inefficiency and quality control problems. Damage to tubing during shipping and handling is highly devastating for those in the glass packaging industry who convert stock glass tubing into individual glass articles. When a converter receives damaged glass tubing, it is typically either discarded or stored in isolation until an investigation is conducted. In other cases, a converter may intentionally or unintentionally use damaged tubing in one or more conversion processes, which can lead to machine blockages and significant downtime.

[0078] Conventional glass tubes used as starting material for conversion operations suffer from poor mechanical properties associated with the finished ends of the glass tubes. In particular, the external shape of the finished ends of conventional glass tubes does not help to avoid damage during typical shipping and handling operations. To avoid the presence of sharp edges at the ends of glass tubes, existing finishing operations glaze the ends of the tubes, leaving open ends with glass beads (glaze) around the edges of the glass tubes. In some cases, the ends of glass tubes are finished by sealing the ends of the tubes to form a flat bottom in an end glazing process commonly referred to as "bottoming". However, the finished ends resulting from both of these end glazing techniques have physical features with a small radius that can act as stress concentration points at the ends of the glass tubes. Therefore, when existing tubes come into contact with each other and with other packaging equipment, such as pallets, these physical features are subjected to high stress levels, which often leads to damage at the ends of the glass tubes, such as cracks. Therefore, in the glass packaging industry, there is a need for glass tubes with improved end shapes that can withstand the typical contact they receive during shipping and handling.

[0079] In addition, conventional finishing operations often introduce defects into the glass tube that can be problematic for the glass tube itself and the converted glass articles produced therefrom. Therefore, there is a demand for glass tubes with reduced defects associated with the finishing operations, as well as for methods and systems that can finish the ends of glass tubes to efficiently produce glass tubes with these attributes.

[0080] This disclosure addresses these needs by introducing a new type of finished end for glass tubes, along with a method and system for manufacturing the new finished end. In particular, this disclosure focuses on glass tubes having dome-shaped ends, which result in improved mechanical properties of the glass tubes and reduced breakage during shipping and handling. Furthermore, the glass tubes having dome-shaped ends of this disclosure are of higher quality than glass tubes with conventional finished ends, due to the method and system used to finish the glass tubes having dome-shaped ends.

[0081] The glass tubes of this disclosure have a domed end glaze at one or both ends of the glass tube. The domed end glaze has a convex outer surface with a larger minimum radius than that of glass tubes with conventional end glazing, such as glass beads or flat bottoms. The domed end glaze disclosed herein is generally a hemisphere of glass that closes the end of the glass tube and provides a rounded outer shape. The rounded outer shape of the domed end glaze reduces stress concentration points (small radii or angles) compared to open ends and / or flat bottoms, and creates a flexible contact surface. Therefore, when a glass tube having a domed end glaze is subjected to typical contact forces associated with shipping and handling, as disclosed herein, the domed end glaze can redistribute the forces over a larger area, thereby reducing the likelihood of damage in the form of chipping, cracking, or breakage. Furthermore, the distribution of contact forces over a larger area of ​​the end of the glass tube may allow the impact energy to be used to reposition the end of the glass tube rather than causing localized fracture in the glass at the end of the tube. Furthermore, as will be discussed in more detail below, the systems and methods disclosed herein for producing glass tubes with dome-shaped ends may, among other features, result in higher quality tube ends (fewer defects) and simplified process operation that improves manufacturing efficiency.

[0082] Referring again to FIG. 1, the glass tube 10 of the present disclosure will be described here in more detail. As previously discussed, the glass tube 10 includes a hollow cylindrical sidewall 12 and dome end glazes 20 at one or more of the ends of the glass tube 10. The dome end glazes 20 can be at the first end 17, the second end 18, or both. The transition between the hollow cylindrical sidewall 12 and the dome end glazes 20 can be defined by a plane P of the end in the hollow cylindrical sidewall 12. The plane P is perpendicular to the central axis A of the glass tube 10. Each of the first end 17 and the second end 18 has an end face P E which is defined as a plane perpendicular to the central axis A and is at the tip of each tube end in the direction of the central axis A (FIGS. 3-5 and 6B). The dome end glazes 20 can have a dome height H defined as the distance between the plane P along the central axis A and the end face P E . The glass tube 10 has an end face P at the first end 17 E to the end face P at the second end 18 along the central axis A E . The glass tube 10 can further have a longitudinal length L (FIG. 2) defined as the distance from to. The longitudinal length L refers to the finished length of the glass tube 10.

[0083] The longitudinal length L of the glass tube 10 can be a multiple of or greater than the outer diameter d1 of the glass tube 10, so as to define the aspect ratio of the glass tube 10. For example, in the embodiment, the longitudinal length L of the glass tube 10 can be 10 times or more d1, 15 times or more d1, 20 times or more d1, 25 times or more d1, 30 times or more d1, 35 times or more d1, 40 times or more d1, 45 times or more d1, or 50 times or more d1. In the embodiment, the longitudinal length L of the glass tube 10 can be 200 mm or more, 210 mm or more, 220 mm or more, 230 mm or more, 240 mm or more, 250 mm or more, 260 mm or more, 270 mm or more, 280 mm or more, 290 mm or more, or 300 mm or more. In the embodiment, the longitudinal length L of the glass tube 10 can be 244 mm or more. In the embodiment, the longitudinal length L of the glass tube 10 may be 310 mm or more. In the embodiment, the longitudinal length L of the glass tube 10 may be 400 mm or more, 500 mm or more, 600 mm or more, 700 mm or more, 750 mm or more, 800 mm or more, 850 mm or more, 900 mm or more, 1000 mm or more, 1100 mm or more, 1200 mm or more, 1300 mm or more, 1400 mm or more, or 1500 mm or more. In the embodiment, the longitudinal length L of the glass tube 10 may be 1502 mm or more. In the embodiment, the longitudinal length L of the glass tube 10 may be 1600 mm or less.

[0084] In this embodiment, the outer diameter d1 of the hollow cylindrical side wall 12 of the glass tube 10 may be approximately 8.15 mm, 16.00 mm, 24.00 mm, 30.00 mm, or 47.00 mm. In this embodiment, the outer diameter d1 of the hollow cylindrical side wall 12 of the glass tube 10 can be 4.00mm to 325.00mm, 4.00mm to 300.00mm, 4.00mm to 250.00mm, 4.00mm to 200.00mm, 4.00mm to 150.00mm, 4.00mm to 100.00mm, 4.00mm to 90.00mm, 4.00mm to 80.00mm, 4.00mm to 70.00mm, 5.00mm to 60.00mm, 5.00mm to 50.00mm, 6.00mm to 50.00mm, 10.00mm to 50.00mm, 10.00mm to 40.00mm, 15.00mm to 40.00mm, or 20.00mm to 40.00mm.

[0085] In the embodiment, the outer diameter d1 of the hollow cylindrical side wall 12 of the glass tube 10 may correspond to the standardized outer diameter of a glass pharmaceutical vial, such as that specified in ISO 8362-1:2018 or a standard created by the Glass Packaging Institute (GPI). In the embodiment, the outer diameter d1 of the hollow cylindrical side wall 12 of the glass tube 10 may correspond to the standardized outer diameter of a glass ampoule, such as that specified in ISO 9187-1:2010. In the embodiment, the outer diameter d1 of the hollow cylindrical side wall 12 of the glass tube 10 may correspond to the standardized outer diameter of a glass syringe, such as that specified in ISO 11040-4. In the embodiment, the outer diameter d1 of the hollow cylindrical side wall 12 of the glass tube 10 may correspond to the standardized outer diameter of a glass cartridge, such as that specified in ISO 21881:2019.

[0086] The dome end glaze 20 is defined by the wall thickness t, which is determined by the distance between the outer surface 24 and the inner surface 26 of the dome wall 22. d It can be formed by a dome wall 22 having a wall thickness t of the dome end glaze 20. In this embodiment, the wall thickness t of the dome end glaze 20 is d This can be less than or equal to the wall thickness t of the hollow cylindrical side wall 12, defined as the distance between the outer surface 14 and the inner surface 16. In this embodiment, the wall thickness t of the dome end glaze 20 is d The wall thickness t of the hollow cylindrical side wall 12 may be greater than or equal to the wall thickness t of the dome end glaze 20. In this embodiment, the wall thickness t of the dome end glaze 20 is greater than or equal to the wall thickness t of the hollow cylindrical side wall 12. d This is uniform across the dome edge glaze 20. In other embodiments, the wall thickness t of the dome wall 22 forming the dome edge glaze 20 is also present. d This can vary based on the position on the dome end glaze 20. For example, in the embodiment, the wall thickness t of the dome wall 22 d This refers to the wall thickness t in the central region of the dome end glaze 20 adjacent to the central axis A. d In comparison, it can be thicker near the hollow cylindrical side wall 12.

[0087] The convex shape of the outer surface 24 of the dome end glaze 20 has a radius of curvature r c It may have the following characteristics. In this embodiment, the radius of curvature r of the convex shape of the outer surface 24c The radius of curvature r of the convex shape is 0.3 times or more d1, 0.4 times or more d1, and 0.45 times or more d1 over positions on the convex shape located at a distance of 0.4 times d1 from the central axis A of the glass tube 10. In the embodiment, the radius of curvature r of the convex shape of the outer surface 24 is 0.3 times or more d1, 0.4 times or more d1. c This is such that, over positions on the convex shape located at a distance of 0.4 times d1 from the central axis A of the glass tube 10, it is 0.7 times or less of d1, 0.6 times or less of d1, or 0.55 times or less of d1.

[0088] In this embodiment, the radius of curvature r of the convex shape of the outer surface 24 c The radius of curvature r of the convex shape is 0.3 to 0.7 times d1 over a position on the convex shape located at a distance of 0.4 times d1 from the central axis A of the glass tube 10. In this embodiment, the radius of curvature r of the convex shape of the outer surface 24 c The radius of curvature r of the convex shape is 0.3 to 0.5 times d1 over positions on the convex shape located at a distance of 0.4 times d1 from the central axis A of the glass tube 10. In this embodiment, the radius of curvature r of the convex shape of the outer surface 24 c d 1の It is 0.5 times to 0.7 times d1. In the embodiment, the radius of curvature r of the convex shape of the outer surface 24 c The radius of curvature r of the convex shape is 0.5 to 0.7 times d1 over positions on the convex shape located at a distance of 0.4 times d1 from the central axis A of the glass tube 10. In this embodiment, the radius of curvature r of the convex shape of the outer surface 24 c The radius of curvature r of the convex shape is 0.4 times d1 or more and 0.6 times d1 or less over a position on the convex shape located at a distance of 0.4 times d1 from the central axis A of the glass tube 10. In the embodiment, the radius of curvature r of the convex shape of the outer surface 24 c This value is between 0.45 times and 0.55 times d1, over a position on the convex shape located at a distance of 0.4 times d1 from the central axis A of the glass tube 10.

[0089] In the embodiment of the glass tube 10 shown in Figure 3, the radius of curvature r of the convex shape of the outer surface 24 cThis is approximately 0.5 times d1 over positions on the convex shape located at a distance of 0.4 times d1 from the central axis A of the glass tube 10. The convex portion of the outer surface 24 corresponding to the positions on the convex shape located at a distance of 0.4 times d1 is illustrated as the shaded portion H in Figure 3. c In embodiments where d1 is approximately 0.5 times, the dome end glaze 20 approximates a glass hemisphere at the end of the glass tube 10. While we do not wish to be bound by theory, the radius of curvature r of the convex shape is... c Embodiments in which d1 is approximately 0.5 times d1 are considered to offer particularly good mechanical properties as a result of the maximum curvature of the outer surface 24 at the end of the glass tube 10 corresponding to the theoretical limit based on the outer diameter d1 of the glass tube 10. As discussed above, feature portions having increased curvature (e.g., smaller radius of curvature) at the end of the glass tube may be subjected to greater localized stress as a result of their limited ability to distribute contact forces over a wider area. The domed end of the glass tube 10 of this disclosure can reduce the maximum curvature of the finished end of the glass tube compared to glass tubes currently available. In embodiments, the radius of curvature r of the convex shape of the outer surface 24 c This value is approximately 0.5 times d1 across the entire convex shape.

[0090] In the embodiment of the glass tube 10 shown in Figure 4, the radius of curvature r of the convex shape of the outer surface 24 c The radius of curvature r is greater than or equal to 0.4 times d1 over the position on the convex shape that is at a distance of 0.4 times d1 from the central axis A of the glass tube 10. As can be observed from Figure 4, the radius of curvature r is less than 0.5 times d1 over the position on the convex shape that is at a distance of 0.4 times d1 from the central axis A of the glass tube 10. c In an embodiment having a radius of curvature r c The radius of curvature is r c The radius of curvature r of the dome end glaze in such embodiments may vary depending on the position on the outer surface 24 where it is measured. c The radius of curvature r of the convex shape may include a tapered region 28 that varies from a relatively large value near the hollow cylindrical side wall 12 to a relatively small value near the central axis A. cIf d1 is less than 0.3 times, the dome end glaze 20 may have limited ability to distribute the contact force over a wider area.

[0091] In the embodiment of the glass tube 10 shown in Figure 5, the radius of curvature r of the convex shape of the outer surface 24 c The radius of curvature r of the convex shape is between 0.5 and 0.7 times d1, over a position on the convex shape located at a distance of 0.4 times d1 from the central axis A of the glass tube 10. c If is greater than 0.7 times d1, the transition between the hollow cylindrical sidewall 12 and the dome end glaze 20, i.e., in plane P, may be associated with a high curvature, thereby providing a potential stress concentration point, which may lead to an increased risk of failure due to contact.

[0092] As discussed above, the dome end glaze 20 of the glass tube 10 is formed by a plane P along the central axis A and the end face P E The dome may have a dome height H defined as the distance between d1 and d1. In an embodiment, the dome height H may be 0.3 times or more d1, 0.4 times or more d1, or 0.45 times or more d1. In an embodiment, the dome height H may be 0.7 times or less d1, 0.6 times or less d1, or 0.55 times or less d1. In an embodiment, the dome height H may be 0.3 to 0.7 times d1, 0.3 to 0.5 times d1, 0.5 to 0.7 times d1, 0.4 to 0.6 times d1, or 0.45 to 0.55 times d1. In an embodiment, the dome height H may be approximately 0.5 times d1.

[0093] In the embodiment, the glass tube 10 may include a first dome end glaze at a first end 17 of the glass tube 10 and a second dome end glaze at a second end 18 of the glass tube 10. In the embodiment, the dome end glaze 20 closes the glass tube 10 at the first end 17, the second end 18, or both. The embodiment in which both ends of the glass tube 10 are closed by the dome end glaze 20 may be particularly suitable for pharmaceutical packaging applications because closing both ends can prevent contaminants from entering the inside of the glass tube 10.

[0094] Referring here to Figures 6A and 6B, in embodiments, the glass tube 10 of the present disclosure may further include vents 40 in the dome end glaze 20. In some cases, conventional glass tube finishing may involve placing vents near the ends of the glass tube for the purpose of reducing pressure into the glass tube during certain transformation operations. Typically, in conventional glass tube finishing processes, vents are introduced through the cylindrical sidewall of the glass tube such that the vents are oriented perpendicular to the central axis A of the glass tube, which, coupled with the narrow radius associated with the transition of the cylindrical sidewall to the flat bottom, creates a stress concentration at the end of the glass tube. This transition and the stress concentration associated with the sidewall vents can increase the likelihood of damage to the end of the tube during typical shipping and handling operations.

[0095] Referring again to Figures 6A and 6B, the glass tube 10 disclosed herein may have vents 40 located in the dome end glaze 20 rather than within the side wall 12 of the glass tube 10. It has been found that glass tubes 10 having a dome end glaze 20 with vents 40 can exhibit improved mechanical properties compared to conventional glass tubes, despite the presence of the vents. While we do not wish to be bound by theory, it is thought that the location of the vents 40 (e.g., the transition from the side wall to the bottom in conventional flat-bottom glass tubes) being isolated from the region of sharp curvature of the end glazing can reduce the potentially detrimental effects of the presence of the vents 40 on the finished end of the glass tube 10. Referring again to Figure 6B, a cross-section of the glass tube 10 with vents 40 passing through the dome end glaze 20 is depicted. Figure 6A depicts an end view of the glass tube 10 with vents 40 passing through the dome end glaze 20. In the embodiment, the dome end glaze 20 may cover at least 65%, at least 70%, at least 70%, at least 75%, at least 80%, or at least 85% of the cross-sectional area of ​​the glass tube 10 at the first end 17, the second end 18, or both.

[0096] In this embodiment, the ventilation holes 40 have a diameter D of 0.01 to 0.25 times d1, 0.05 to 0.20 times d1, or 0.10 to 0.20 times d1. v It may have a diameter D of 1 mm to 5 mm or 2 mm to 4 mm. In this embodiment, the ventilation hole 40 has a diameter D of 1 mm to 5 mm or 2 mm to 4 mm. v It may have a diameter D of 3 mm. In this embodiment, the ventilation hole 40 has a diameter D v It may have.

[0097] In the embodiments shown in Figures 6A and 6B, the vent 40 may be aligned with the central axis A of the glass tube 10. In the embodiments, the vent 40 may be offset from the central axis A of the glass tube 10. Referring now to Figure 7, in the embodiments, the vent 40 may be offset from the central axis A of the glass tube 10, so that the center line CL of the vent 40 makes an angle α of less than 80 degrees, less than 70 degrees, or less than 45 degrees with the central axis A of the glass tube 10. In the embodiments, the center line CL of the vent 40 makes an angle α of about 45 degrees with the central axis A of the glass tube 10. In the embodiments, the center line CL of the vent 40 is not perpendicular to the central axis A of the glass tube 10.

[0098] In an embodiment of the glass tube 10 including the ventilation hole 40, the radius of curvature r of the convex shape of the outer surface 24 c This does not include the area of ​​the dome end glaze 20 that has been reshaped as a result of the presence of the ventilation holes 40. That is, over a position on the convex shape where the glass tube 10 is at a distance of 0.4 times d1 from the central axis A of the glass tube 10, a specific radius of curvature r c When determining whether or not to include this feature, the high curvature (low radius of curvature) associated with the wall of the dome end glaze 20 surrounding the ventilation opening 40 should not be taken into consideration.

[0099] In embodiments, the glass tube 10 may be substantially free of surface defects, such as, but not limited to, cracks, scratches, or any other surface inclusions. In embodiments, the glass tube 10 may have an acceptable quality level (AQL) of less than 0.25 for end cracks having a crack length greater than 2 mm. The acceptable quality level (AQL) is defined according to ISO 2859-1. End cracks refer to cracks that appear at the axial ends of the glass tube 10. In embodiments, the glass tube 10 may have an AQL of 0.025 or less for surface cracks of any size and length. Surface cracks refer to cracks on the outer and / or inner surfaces (i.e., not the end faces) of the glass tube 10.

[0100] In the embodiment, the glass tube 10 may contain substantially no glass particles fused to the outer surface 14 and inner surface 16 of the hollow cylindrical side wall 12. In the embodiment, the glass tube 10 may have 0 glass particles with a diameter greater than 0.5 mm attached to the outer surface 14 or inner surface 16 of the glass tube 10. In the embodiment, the glass tube 10 may have 5 or fewer glass particles with a diameter of 0.2 mm to less than 0.5 mm attached to the outer surface 14 or inner surface 16 of the glass tube 10. In the embodiment, the glass tube 10 may have an AQL of less than 0.1 for impurities larger than 1 mm in size that are on the outer surface 14 of the glass tube 10 and are not easily removed. In the embodiment, the glass tube 10 may have an AQL of less than 0.1 for impurities larger than 0.5 mm in size that are on the inner surface 16 of the glass tube 10 and are not easily removed.

[0101] In conventional tube manufacturing processes, glass tubes are cut to their final length using a combination of mechanical tools for cracking (creating cracks), heating with a gas burner, and quenching the glass tube to create thermal shock conditions and propagate the cracks around the circumference of the glass tube, thereby completing the separation of sections from the ends of the glass tube. After cutting is performed at both ends, the edges at the ends of the glass tube are finished through flame polishing (i.e., end glazing) using a gas burner. While conventional manufacturing processes for cutting to final length and edge finishing are well established, they present many challenges and opportunities for improvement, especially considering the increasing demand for pharmaceuticals today, as well as the growing emphasis on high quality and manufacturing efficiency.

[0102] There is a growing demand for end finishing steps in tube manufacturing processes that enable high quality tube ends (free from glass defects, acceptable morphology, and high strength) and accurate final tube lengths, while achieving low loss and high yield at high processing speeds. As mentioned above, existing cutting processes that perform final length cutting rely on the creation of initial defects on the tube surface performed by a cutting blade (or other mechanical tool), and the subsequent propagation of cracks. Creating a fracture surface that starts from an initial mechanical defect and propagates around the circumference of the glass tube by thermal stress is not very precise and requires several processing steps, making it inefficient. In addition to this, edge flame polishing is typically performed following separation, which is necessary to repair surface defects created by the scribing and folding methods. Edge or end flame polishing means an additional process step and requires extra time to complete, thereby further reducing the efficiency of the manufacturing process.

[0103] Products in pharmaceutical packaging, such as vials, cartridges, syringes, ampoules, or other containers converted from glass tubing, require a high degree of cleanliness. The mechanical generation of cracks used in current conventional end-finishing processes damages the tube surface, generating glass particles that contaminate the outer and inner surfaces of the glass tube. These glass particles then need to be removed from the glass tube through a thorough cleaning process. This cleaning process becomes more complex if a large number of particles are generated during the manufacturing process, particularly if glass particles adhere to the surface by fusing to the glass surface during flame polishing of the glass tube edges, for example.

[0104] Furthermore, as discussed above, certain glass tube products require sealed tube ends. In conventional glass tube manufacturing processes, sealing the ends of the glass tubes is currently performed at the end of the conveyor line as an additional step, using a gas burner after cutting to the final length and edge polishing. The use of a gas burner to seal the ends of the glass tubes adds an additional manufacturing step, which reduces the efficiency of the manufacturing process. Therefore, a more efficient end finishing process is needed to improve the quality of the glass tubes produced therefrom.

[0105] In addition to glass tubes having dome-shaped ends as discussed above, this application also covers systems and methods for separating and finishing the ends of glass tubes during the tube production process (i.e., from molten glass) or, alternatively, independently of the tube production process. The systems and methods disclosed herein demonstrate improved manufacturing efficiency by combining the cutting to final length and edge polishing steps associated with conventional tube manufacturing processes. Furthermore, the systems and methods disclosed herein do not require the series of steps associated with the conventional cutting to final length process, which includes mechanical tools for crack (scratch) formation, heating with a gas burner, and quenching of the glass tube, as discussed above. By omitting the additional scratch-heat-quench sequence of the conventional cutting to final length operation, the associated generation of glass particles during flame polishing of the glass tube ends and the potential adhesion of glass particles can be avoided. Avoiding the generation of glass particles and the potential adhesion of glass particles to the glass tube reduces the need for a cleaning process designed to remove such particles. Furthermore, as will be explained in more detail below, the systems and methods disclosed herein for finishing the ends of glass tubes by creating dome-shaped ends can result in the glass tubes being substantially free of end cracks and inclusions, which reduces the edge polishing requirements that are typically required after conventional cutting processes to the final length.

[0106] Furthermore, glass tubes manufactured to be substantially free of both fused glass particles and end cracks and inclusions are of higher quality and, when used as stock glass tubes for conversion operations, can lead to improved quality and higher yields of glass articles produced therefrom. In addition, the systems and methods disclosed herein produce glass tubes with improved mechanical properties, such as higher durability of the glass tubes during typical shipping and handling operations. Moreover, for glass tubes requiring sealed ends, the systems and methods disclosed herein avoid the need for an additional bottoming step at the end of the conveyor. The systems and methods disclosed herein form sealed ends during the separation step and are therefore considered particularly efficient for the production of glass tubes requiring sealed ends, among other features.

[0107] The systems and methods of this disclosure are described in more detail here. The systems and methods disclosed herein may be used independently or as part of a production process for manufacturing glass tubes. In a production process for manufacturing glass tubes, molten glass is first formed into a continuous hollow glass cylinder using a glass tube forming process. The process for forming the molten glass into a continuous hollow glass cylinder may include the Danner process, the Bellow process, or other currently or futuristically developed processes for producing continuous hollow glass cylinders. The continuous hollow glass cylinder is then pulled through an annealing process and subsequently cut into individual glass tubes having initial lengths.

[0108] Referring to Figures 8 and 9, one embodiment of a system 200 for producing multiple glass tubes 10 is schematically shown. The system 200 may include a melting furnace 210, a glass tube forming apparatus 220 downstream of the melting furnace 210, a muffle furnace 230 downstream of the glass tube forming apparatus 220, an annealing section 240 downstream of the muffle furnace 230, a tube puller 250 downstream of the annealing section 240, a continuous tube cutter 260 downstream of the tube puller 250, and a conveyor 110 disposed downstream of the continuous tube cutter 260.

[0109] In the operation of system 200, glass 202 is introduced into a melting furnace 210, which is operable to melt the glass and form molten glass 212. The molten glass 212 is then passed to a glass tube forming apparatus 220, which is operable to form the molten glass 212 into a continuous hollow glass cylinder 222. As shown in Figure 9, in an embodiment, the glass tube forming apparatus 220 may be a tube forming apparatus used in the Danner process, where the molten glass 212 flows from a feeder into a rotatable inclined hollow cylinder and is stretched by a tube puller 250 from the rotatable inclined hollow cylinder into a muffle furnace 230 to produce a continuous hollow glass cylinder 222. While the continuous hollow glass cylinder 222 is being stretched from the glass tube forming apparatus 220, compressed air or other gas supplied to the center of the continuous hollow glass cylinder 222 through the glass tube forming apparatus 220, along with a vacuum applied from the outside of the continuous hollow glass cylinder 222, helps to control the diameter of the tube and prevent it from collapsing until it has cooled sufficiently to retain its shape. Although shown as the Danner process in Figure 9, it is understood that the continuous hollow glass cylinder 222 may be fabricated using the Bellow process or any other current or future process for fabricating a continuous hollow glass cylinder.

[0110] Referring again to Figures 8 and 9, after formation, the continuous hollow glass cylinder 222 is then pulled through the muffle furnace 230 and the annealing section 240 by a tube puller 250. The annealing section 240 may be operable to anneal the continuous hollow glass cylinder 222 to produce the annealed continuous hollow glass cylinder 242. The tube puller 250 may include one or more sets of drive rollers 252 operable to exert sufficient tensile force on the annealed continuous hollow glass cylinder 242 to pull it through the muffle furnace 230 and the annealing section 240. After passing through the annealing section 240 and the tube puller 250, the annealed continuous hollow glass cylinder 242 is passed to a tube cutter 260, where the annealed continuous hollow glass cylinder 242 is roughly cut into glass tubes 10 having an initial length.

[0111] Since the initial cut performed by the pipe cutter 260 is a rough cut, further processing of the glass tube 10 is performed to cut the glass tube 10 to its final length and to finish the end of the glass tube 10. Referring to Figure 8, after the pipe cutter 260, the glass tube 10 is transported in a direction 116 perpendicular to the stretching direction 224 for end finishing and creating a dome-shaped end.

[0112] Referring again to Figure 10, the system 100 of the present disclosure for finishing one or both ends of a glass tube 10 may include a conveyor 110 that is operable to translate the glass tube 10 horizontally and, at the same time, rotate each of the glass tubes 10 around the central axis A of each glass tube 10. The system 100 further includes a separation station 120 configured to remove the annular segment 30 of each glass tube 10 from the starting end 32 of the glass tube 10, and removing the annular segment 30 (Figure 12B) from the starting end 32 of the glass tube 10 forms a glass meniscus 21 on the new end 34 of the glass tube 10. Once the annular segment 30 of each glass tube 10 has been removed, the glass tube 10 has a longitudinal length L as described above, i.e., the longitudinal length L of the glass tube may be a multiple of or greater than the outer diameter d1 of the glass tube 10, so as to define the aspect ratio of the glass tube 10. In embodiments, the longitudinal length L of the glass tube 10 may be 30 times or more d1. In the embodiment, system 100 is configured to finish the end of a glass tube 10 such that the finished glass tube 10 has a longitudinal length L of 800 mm or more. In the embodiment, system 100 may further include a polishing station 130 configured to form a glass meniscus 21 at a new end 34 of the glass tube 10 in order to form a dome end glaze 20 at the new end 34 of the glass tube 10, the dome end glaze 20 having a convex outer surface 24. In the embodiment, system 100, for example, a conveyor 110, may be configured to receive glass tubes 10 from a tube manufacturing process such as system 200 discussed above.

[0113] Various operations of System 100 will be described with reference to “Glass Tube 10” or “Glass Tube 10,” but it should be understood that the systems and methods disclosed herein are applicable to the manufacture of multiple glass tubes 10. Each glass tube 10 may pass through, but is not limited to, one or more processing stations such as preheating stations, separation stations, polishing stations, venting stations, forming stations, or combinations thereof.

[0114] Referring again to Figure 10, in an embodiment, the conveyor 110 may comprise a plurality of conveyor rollers 112 and a plurality of belts 114. The conveyor 110 may be operable to translate the plurality of glass tubes 10 horizontally in the machine direction 116 (i.e., in the +X direction of the coordinate axes in Figure 10 (perpendicular to the central axis A of the glass tubes 10)), while also rotating each of the glass tubes 10 around the central axis A of the glass tubes 10. The plurality of conveyor rollers 112 may be arranged in parallel in the + / -X direction of the coordinate axes in Figure 10. In an embodiment, the axis of rotation of each conveyor roller 112 may extend axially in the + / -Y direction, and may be parallel to the central axis A of the glass tubes 10. The conveyor rollers 112 may be rotatable in the same direction of rotation. The conveyor 110 may include multiple sets of conveyor rollers 112, each set of conveyor rollers 112 being arranged in parallel in the + / -X direction of the conveyor 110, but separated from other sets of conveyor rollers 112 in the + / -Y direction to support the glass tube 10 at various positions along the length of the glass tube 10.

[0115] Each of the glass tubes 10 is positioned within a convergence gap between two adjacent conveyor rollers 112 and can be supported through contact with the adjacent conveyor rollers 112. In the embodiment, each of the glass tubes 10 is cut to an initial length by a tube cutter 160 (Figure 8) and then positioned within a convergence gap between two adjacent conveyor rollers 112. While the conveyor rollers 112 are rotating, the contact between the outer surface 14 of the glass tube 10 and the surface of the conveyor rollers 112 can cause the glass tube 10 to rotate around its central axis A.

[0116] Multiple belts 114 may be operably coupled to a drive motor (not shown) which can move the belts 114 along a belt path. The belts 114 may contact portions of the conveyor rollers 112 such that, as the belts 114 move along the belt path, the contact between the belts 114 and the conveyor rollers 112 can cause the conveyor rollers 112 and the glass tubes 10 disposed between each of the conveyor rollers 112 to translate horizontally (i.e., in the +X direction of the coordinate axes in Figure 10). Contact of one or more of the conveyor rollers 112 of the belts 114 may further cause the conveyor rollers 112 to rotate, thereby facilitating the rotation of the glass tubes 10. In embodiments, the drive motor operably coupled to the belts 114 may be a variable-speed drive which may be operable to change the speed of the conveyor 110 in order to translate the multiple glass tubes 10. Although described as having multiple conveyor rollers 112 and a belt 114, it is understood that the conveyor 110 can have other configurations, as long as the conveyor is capable of operating to translate the glass tubes 10 horizontally and simultaneously to rotate the glass tubes 10 around the central axis A of each glass tube. As shown in Figure 10, the conveyor 110 may be capable of operating to translate the glass tubes 10 through a separation station 120 and a polishing station 130.

[0117] As described above, the system 100 may include a separation station 120 configured to remove the annular segment 30 of the glass tube 10 from the starting end 32 of the glass tube 10. As previously discussed, removing the annular segment 30 from the starting end 32 of the glass tube 10 forms a glass meniscus 21 on the new end 34 of the glass tube 10. In embodiments, the separation station 120 includes one or more preheating stations 310 and a pulling station 320. One or more preheating stations 310 may be configured to heat a target region 50 of the glass tube 10 adjacent to the starting end 32 of the glass tube 10. The pulling station 320 may be operable to transport the annular segment 30 of the glass tube 10 away from the glass tube 10 in a direction parallel to the central axis A of the glass tube 10.

[0118] Referring here to Figure 11, each of the one or more preheating stations 310 may include one or more gas burners 312 for heating a target area 50 of the glass tube 10 circumferentially as the conveyor 110 rotates the glass tube 10. The gas burners 312 may be configured to produce a flame and direct it toward the hollow cylindrical sidewall 12 within the target area 50, as shown in Figure 11. In embodiments, the target area 50 may be 200 mm or less from the starting end 32, 100 mm or less from the starting end 32, or 50 mm or less from the starting end 32 (measured from the center of the target area 50 relative to the central axis A of the glass tube 10). In embodiments, the target area 50 may be 25 mm or more from the starting end 32 of the glass tube 10. In this context, the distance between the target area 50 and the starting end 32 of the glass tube 10 refers to the distance between the center of the target area, i.e., the portion where heating by the gas burners 312 is maximum, and the end face 33 of the starting end 32.

[0119] One or more preheating stations 310 can heat the target region 50 of the glass tube 10 to a temperature in which the viscosity of the glass in the target region 50 is sufficiently reduced so that the glass tube 10 can be separated into two distinct parts by applying a tensile force to the end of the glass tube 10 at least axially with respect to the central axis A.

[0120] Figure 11 depicts a single gas burner 312, but it is understood that multiple gas burners 312 may be employed in each of one or more preheating stations 310. Each gas burner 312 may be fluidly coupled to a fuel source (not shown), an oxygen source (not shown), and optionally an air source (not shown). Examples of fuels for the gas burners 312 may include, but are not limited to, hydrogen, hydrocarbon fuel gases such as methane, propane, and butane, other fuel gases, or combinations thereof. Each gas burner 312 may include a fuel control valve (not shown) for controlling the flow rate of fuel gas to the gas burner 312. Each gas burner 312 may also include an oxygen control valve (not shown) for controlling the mass flow rate of oxygen to the gas burner 312. Each gas burner 312 may further include an air control valve (not shown) for optionally controlling the flow rate of air to the gas burner 312. The gas burner 312 can burn a fuel gas in the presence of oxygen and / or air to produce a flame that heats at least a target area 50 of the glass tube 10. The control parameters of one or more preheating stations 310 can be adjusted according to the thickness t or outer diameter d1 of the glass tube 10. Furthermore, although one or more preheating stations 310 of the system 100 are described herein as using a gas burner to heat the glass tube 10, it is understood that the glass tube 10 may be heated using other heating elements or methods other than a gas burner.

[0121] The tension station 320 of the system 100 includes one or more devices that are operable to apply a tensile force to each end of the glass tubes 10 at least axially with respect to the central axis A of each of the multiple glass tubes 10. The tension station 320 may be located downstream of one or more preheating stations 310. Referring here to Figure 12A, in an embodiment the tension station 320 may include a gas burner 322, an end support roller 324 configured to support the starting end 32 of the glass tube 10, and at least one separation roller 326 configured to apply an axial tensile force F to the starting end 32 of the glass tube 10, the axial tensile force F separating the annular segment 30 from the glass tube 10.

[0122] The gas burner 322 of the tensile station 320 may provide additional heat to the target region 50 to further reduce the viscosity of the target region 50, so that the glass tube 10 can be separated into two distinct parts by applying a tensile force to the end of the glass tube 10 at least axially with respect to the central axis A.

[0123] Figure 12A depicts a single gas burner 322, but it is understood that multiple gas burners 322 may be employed in the pull station 320. Each gas burner 322 may be fluidly coupled to a fuel source (not shown), an oxygen source (not shown), and optionally an air source (not shown). Examples of fuels for the gas burners 322 may include, but are not limited to, hydrogen, hydrocarbon fuel gases such as methane, propane, and butane, other fuel gases, or combinations thereof. Each gas burner 322 may include a fuel control valve (not shown) for controlling the flow rate of fuel gas to the gas burner 322. Each gas burner 322 may also include an oxygen control valve (not shown) for controlling the mass flow rate of oxygen to the gas burner 322. Each gas burner 322 may further include an air control valve (not shown) for optionally controlling the flow rate of air to the gas burner 322. The gas burner 322 can burn a fuel gas in the presence of oxygen and / or air to produce a flame that heats at least a target area 50 of the glass tube 10. The control parameters of the tension station 320 can be adjusted according to the thickness t or outer diameter d1 of the glass tube 10. Furthermore, although the tension station 320 of system 100 is described herein as heating the glass tube 10 using a gas burner, it is understood that the glass tube 10 may be heated using other heating elements or methods other than a gas burner.

[0124] Referring again to Figure 12A, the end support rollers 324 can operate similarly to the conveyor rollers 112. That is, the end support rollers 324 can be arranged in parallel in the + / -X direction of the coordinate axes in Figure 12A. In embodiments, the rotation axis of each end support roller 324 can extend axially in the + / -Y direction, and may be parallel to the central axis A of the glass tube 10. The end support rollers 324 can rotate in the same rotation direction. While the end support rollers 324 are rotating, the contact between the outer surface 14 of the glass tube 10 and the surface of the end support rollers 324 can rotate the glass tube 10 around the central axis A of the glass tube 10 while simultaneously providing support to the starting end 32 of the glass tube 10. The relative positions of the end support rollers 324 along the length of the glass tube 10 can be adjusted as needed to ensure sufficient support for the separation operation.

[0125] Continuing to refer to Figure 12A, at least one separation roller 326 may be positioned on the end support roller 324 so that the glass tube 10 can be positioned between them. The glass tube 10 may be in contact with both the end support roller 324 and at least one separation roller 326 on approximately both sides of the glass tube 10. At least one separation roller 326 may have a roller rotation axis 326-1 that makes an angle β with respect to the central axis A of the glass tube 10 at 10 to 80 degrees, 20 to 70 degrees, 30 to 60 degrees, or 40 to 50 degrees. In this embodiment, the angle β between the roller rotation axis 326-1 and the central axis A of the glass tube 10 is approximately 45 degrees.

[0126] The end support roller 324 and at least one separation roller 326 may be configured to grip the glass tube 10 between them. As the conveyor 110 translates the glass tube through the pulling station 320, the rotation of at least one separation roller 326 at an angle with respect to the direction 116 in which the glass tube is being conveyed exerts an axial tensile force F on the starting end 32 of the glass tube 10. The magnitude of the axial tensile force F can be adjusted, for example, by modifying the distance between the end support roller 324 and at least one separation roller 326. Reducing the distance between these rollers may increase the gripping force the rollers have on the glass tube 10, and the reduction in slip associated with the tightened gripping force may result in an increase in the magnitude of the axial tensile force F. In embodiments, the separation roller 326 may be driven.

[0127] Figure 12B depicts the glass tube 10 within the pulling station 320 of the separation station 120 after the annular segment 30 has been separated from the glass tube 10. As discussed above, removing the annular segment 30 of the glass tube 10 simultaneously forms a glass meniscus 21 on the new end 34 of the glass tube 10.

[0128] Referring here to Figure 13A, in the embodiment, the pulling station 320 may include a gripper configured to grip the starting end 32 of the glass tube 10 and apply an axial pulling force F, in addition to or as an alternative to the end support roller 324 and at least one separation roller 326, thereby separating the annular segment 30 from the glass tube 10. In the embodiment shown in Figure 13A, the gripper is a three-finger chuck 328, which is configured to grip the starting end 32 of the glass tube 10 with its fingers 329 and move away from the glass tube 10 along the central axis A of the glass tube 10 to apply an axial pulling force F to the starting end 32 of the glass tube 10. The fingers 329 of the three-finger chuck 328 may be made of a high-temperature plastic material such as polyimide material. The three-finger chuck 328 may be supported by a piston 331 configured to move the three-finger chuck away from the glass tube 10. The three-finger chuck 328 may also be rotatable about its central axis and / or translatable along the mechanical direction 116 of the conveyor 110.

[0129] Figure 13B illustrates the glass tube 10 in the pulling station 320 of the separation station 120 after the annular segment 30 has been separated from the glass tube 10 by the three-finger chuck 328, for example, via the retraction of the piston 331. It should be understood that the three-finger chuck 328 is just one form of gripper capable of separating the annular segment 30 from the glass tube 10 by applying an axial tensile force F to the starting end 32 of the glass tube 10. Utilizing a gripper option in the pulling station 320 can provide a flexible separation process, which may be advantageous given that the glass tubes 10 used as starting materials in the glass packaging industry have a wide range of outer diameters d1.

[0130] As discussed above, the polishing station 130 may be operable to shape the glass meniscus 21 at the new end 34 of the glass tube 10 so as to form a dome end glaze 20 having a desired radius of curvature at the new end 34 of the glass tube 10. As shown in Figure 10, the polishing station 130 may be located downstream of the separation station 120. Referring now to Figure 14, the polishing station 130 may include a gas burner 332, such as a flame polishing torch, configured to flame polish the glass meniscus 21 at the new end 34 of the glass tube 10.

[0131] The final convex shape of the outer surface 24 of the dome end glaze 20 can be modified by exposing the glass meniscus 21 to the flame of a gas burner 332. When the flame of the gas burner 332 heats the glass meniscus 21, the viscosity of the molten glass forming the glass meniscus 21 decreases, and the surface tension drives the reshaping of the glass meniscus 21 and the corresponding convex shape of the dome end glaze 20.

[0132] In one embodiment, the polishing station 130 may be configured to modify the shape of the glass meniscus 21, thereby the outer surface 24 of the resulting dome end glaze 20 having a radius of curvature r greater than or equal to 0.4 times d1 over a convex shape located at a distance of 0.4 times d1 from the central axis A of the glass tube 10. c It includes a convex shape having a convex shape. In an embodiment, the polishing station 130 may be configured to modify the shape of the glass meniscus 21, thereby the outer surface 24 of the resulting dome end glaze 20 having a radius of curvature r of about 0.5 times d1 or more over a position on the convex shape that is 0.4 times d1 from the central axis A of the glass tube 10. c It includes a convex shape having a radius of curvature r of 0.4 to 0.6 times d1 over a position on the convex shape that is 0.4 to d1 from the central axis A of the glass tube 10. In the embodiment, the polishing station 130 may be configured to modify the shape of the glass meniscus 21 so that the outer surface 24 of the resulting dome end glaze 20 has a radius of curvature r of 0.4 to d1 and 0.6 times d1 over a position on the convex shape that is 0.4 to d1 from the central axis A of the glass tube 10. cIt includes a convex shape having a radius of curvature r of at least 0.3 and not more than 0.7 times d1 over a position on the convex shape that is at a distance of 0.4 times d1 from the central axis A of the glass tube 10. In the embodiment, the polishing station 130 may be configured to modify the shape of the glass meniscus 21 so that the outer surface 24 of the resulting dome end glaze 20 has a radius of curvature r of at least 0.3 and not more than 0.7 times d1 over a position on the convex shape that is at a distance of 0.4 times d1 from the central axis A of the glass tube 10. c It includes a convex shape having a radius of curvature r of 0.45 to 0.55 of d1 over a position on the convex shape that is 0.4 times d1 from the central axis A of the glass tube 10. In the embodiment, the polishing station 130 may be configured to modify the shape of the glass meniscus 21 so that the outer surface 24 of the resulting dome end glaze 20 has a radius of curvature r of 0.45 to 0.55 of d1 over a position on the convex shape that is 0.4 times d1 from the central axis A of the glass tube 10. c Includes a convex shape having a certain characteristic.

[0133] Figure 14 depicts a single gas burner 332, but it is understood that two or more gas burners 332 may be employed in the polishing station 130. Each gas burner 332 may be fluidly coupled to a fuel source (not shown), an oxygen source (not shown), and optionally an air source (not shown). Examples of fuels for the gas burners 332 may include, but are not limited to, hydrogen, hydrocarbon fuel gases such as methane, propane, and butane, other fuel gases, or combinations thereof. Each gas burner 332 may include a fuel control valve (not shown) for controlling the flow rate of fuel gas to the gas burner 332. Each gas burner 332 may also include an oxygen control valve (not shown) for controlling the mass flow rate of oxygen to the gas burner 332. Each gas burner 332 may further include an air control valve (not shown) for optionally controlling the flow rate of air to the gas burner 332. The gas burner 332 can burn fuel gas in the presence of oxygen and / or air to produce a flame for heating the glass meniscus 21. The control parameters of the polishing station 130 can be adjusted according to the thickness t or outer diameter d1 of the glass tube 10.

[0134] As previously discussed, the process disclosed herein for finishing the ends of glass tubes to produce dome end glazes can reduce the amount of defects in the glass and reduce the deposition of molten glass particles on the surface of the glass tubes compared to conventional end finishing processes.

[0135] In an embodiment, the system 100 may include a venting station 140 positioned downstream of the polishing station 130. The venting station 140 may be operable to form vents 40 in the dome end glaze 20. Referring to Figure 15, in an embodiment, the venting station 140 may include a venting burner 342 configured to form vents 40 in the dome end glaze 20. In an embodiment, the venting burner 342 may be a pen silverer having a focused flame with a narrow heating area. The venting burner 342 may be positioned to direct the flame produced by the venting burner 342 in a specific area of ​​the dome end glaze 20. In the embodiment shown in Figure 15, the axis 342-1 of the venting burner 342 is substantially aligned with the central axis A of the glass tube 10, so that the centerline CL of the resulting vents 40 is substantially aligned with the central axis A. In other embodiments, the axis 342-1 of the vent burner 342 may form an angle (not shown) with the central axis A of the glass tube 10, thereby causing the center line CL of the vent 40 to form an angle α of approximately 45 degrees with the central axis A of the glass tube 10. In embodiments, the axis 342-1 of the vent burner 342 may form an angle (not shown) with the central axis A of the glass tube 10, thereby causing the center line CL of the vent 40 to form an angle α of less than 80 degrees, less than 70 degrees, or less than 45 degrees with the central axis A of the glass tube 10. In embodiments, the axis 342-1 of the vent burner 342 may form an angle (not shown) with the central axis A of the glass tube 10, thereby causing the center line CL of the vent 40 to be not perpendicular to the central axis A of the glass tube 10.

[0136] The vent burner 342 may be fluidically coupled to one or more of the following: a fuel gas source (not shown), an oxygen source (not shown), an air source (not shown), or a combination thereof. Examples of fuels for the vent burner 342 may include, but are not limited to, hydrogen, hydrocarbon fuel gases such as methane, propane, and butane, other fuel gases, or combinations thereof. The vent burner 342 may include a fuel control valve (not shown) for controlling the flow rate of fuel gas to the vent burner 342. The vent burner 342 may also include an oxygen control valve (not shown) for controlling the mass flow rate of oxygen to the vent burner 342. The vent burner 342 may further include an air control valve (not shown) for optionally controlling the flow rate of air to the vent burner 342. The vent burner 342 can burn a fuel gas in the presence of oxygen and / or air to produce a flame for melting and opening the dome end glaze 20 to form the vent 40. The control parameter of the vent station 140 is the thickness t of the dome end glaze 20. d It can be adjusted accordingly.

[0137] In this embodiment, the vent burner 342 has a diameter D of 0.01 to 0.25 times d1, 0.05 to 0.20 times d1, or 0.10 to 0.20 times d1. v It may have a heating area sufficient to produce a vent 40 having a diameter D of 1 mm to 5 mm or 2 mm to 4 mm. In this embodiment, the vent burner 342 has a diameter D of 1 mm to 5 mm or 2 mm to 4 mm. v It may have a heating area sufficient to produce a vent 40 having a diameter D v The heating surface may be sufficient to produce a vent 40 having the following characteristics. After the formation of the vent 40, the dome end glaze 20 may cover at least 40%, at least 45%, at least 50%, at least 55%, at least 60%, at least 65%, at least 70%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, or at least 98% of the cross-sectional area of ​​the glass tube 10. For example, a glass tube 10 with an outer diameter d1 of 16.00 mm and a diameter Dv If the glass tube 10 has a dome end glaze 20 with 3.0 mm ventilation holes 40, the cross-sectional area of ​​the glass tube 10 is 201.1 mm². 2 The cross-sectional area of ​​the ventilation holes is 7.1 mm². 2 Therefore, the dome end glaze 20 covers approximately 96.5% of the cross-sectional area of ​​the glass tube 10.

[0138] Referring again to Figure 10, in an embodiment, the system 100 may include a forming station 150 positioned downstream of the polishing station 130. The forming station 150 may be operable to reshape the glass meniscus 21 to correct the shape of the resulting dome end glaze 20. Referring to Figure 16, the forming station 150 may include a forming tool 352 operable to deform the molten glass. The forming tool 352 may be rotatable around a tool axis 352-1. In an embodiment, the tool axis 352-1 of the forming tool 352 may be parallel to the central axis A of the glass tube 10. The forming tool 352 may have forming features 353 designed to achieve a desired shape of the glass meniscus 21. The forming features 353 have a desired radius of curvature r of the dome end glaze 20. c The radius of curvature r selected based on this f It may have the following. In an embodiment, the forming feature 353 may be configured to produce a tapered region of the dome end glaze 20, as discussed in more detail above. In an embodiment of the system 100 including a venting station 140, the forming station 150 may be positioned upstream of the venting station 140.

[0139] In an embodiment, the system 100 may be configured to finish both the first end 17 and the second end 18 of the glass tube 10. In such an embodiment, the separation station 120 may be configured to (i) remove a first annular segment of the glass tube from a first starting end of the glass tube, the removal of the first annular segment from the first starting end of the glass tube being the removal of a first glass meniscus on the first new end of the glass tube, and (ii) remove a second annular segment of the glass tube from a second starting end of the glass tube, the removal of the second annular segment from the second starting end of the glass tube being the removal of a second glass meniscus on the second new end of the glass tube. The polishing station 130 may be configured to (i) polish the first glass meniscus and the first new end of the glass tube in order to form a first dome end glaze at the first new end of the glass tube, and (ii) polish the second glass meniscus and the second new end of the glass tube in order to form a second dome end glaze at the second new end of the glass tube. The resulting glass tube 10 comprises a first dome end glaze having a first outer surface having a first convex shape, and a second dome end glaze having a second outer surface having a second convex shape.

[0140] In embodiments where system 100 is configured to finish both the first end 17 and the second end 18 of the glass tube 10, subsystems of system 100, such as the separation station 120 and the polishing station 130, may be configured in the same manner as those discussed herein and shown in the drawings. As discussed above, the glass tube 10 having dome-shaped ends at both ends is considered particularly useful in pharmaceutical packaging applications where the cleanliness of the tube is of greater importance.

[0141] Herein, a method for producing a glass tube 10 using the system 100 disclosed herein is described in more detail. Referring again to Figure 10, the method of the disclosure for finishing one or more ends of a glass tube 10 includes rotating the glass tube 10 about a central axis A and removing an annular segment 30 of the glass tube 10 from a starting end 32 of the glass tube 10, wherein removing the annular segment 30 from the starting end 32 of the glass tube 10 forms a glass meniscus 21 on a new end 34 of the glass tube 10, and polishing the glass meniscus 21 at the new end 34 of the glass tube 10 to form a dome end glaze 20 at the new end 34 of the glass tube 10. Furthermore, the method of the disclosure for finishing one or both ends of a glass tube 10 may be used to produce a glass tube 10 having a longitudinal length L which may be 30 times or more d1. In embodiments, the method of the disclosure may be used to finish one or both ends of a glass tube having a longitudinal length L of 800 mm or more.

[0142] A method disclosed herein for finishing one or both ends of a glass tube 10 may include receiving the glass tube 10 from a tube manufacturing process, for example, the system 200 described above and shown in Figures 8 and 9, before rotating the glass tube 10 around a central axis A.

[0143] Referring here to Figure 10, rotating the glass tube 10 around its central axis A may also include translating the glass tube 10 horizontally in the machine direction 116 of the conveyor 110 (i.e., in the +X direction of the coordinate axes in Figure 10 (perpendicular to the central axis A of the glass tube 10)), while simultaneously rotating the glass tube 10 around its central axis A. While the conveyor roller 112 is rotating, contact between the outer surface 14 of the glass tube 10 and the surface of the conveyor roller 112 may cause the glass tube 10 to rotate around its central axis A. The method may also include translating the glass tube 10 through the conveyor 110, passing through the separation station 120 and the polishing station 130.

[0144] Referring again to Figures 11 to 13B, removing the annular segment 30 from the starting end 32 of the glass tube 10 may include heating a target region 50 of the glass tube 10 adjacent to the starting end 32 and transporting the annular segment 30 of the glass tube 10 away from the glass tube 10 in a direction parallel to the central axis A of the glass tube 10. Referring to Figure 11, heating the target region 50 of the glass tube 10 may include heating the glass tube 10 circumferentially as the glass tube 10 is rotated using the gas burner 312. As discussed above with respect to system 100, the target region 50 may be 200 mm or less, 100 mm or less, or 50 mm or less from the starting end 32 of the glass tube 10. In embodiments, the target region 50 may be 25 mm or more from the starting end 32 of the glass tube 10.

[0145] Referring here to Figures 12A and 12B, transporting the annular segment 30 of the glass tube 10 away from the glass tube 10 may include bringing the starting end 32 of the glass tube 10 into contact with at least one separation roller 326 having a roller rotation axis 326-1 that forms an angle β between 10 and 80 degrees with the central axis A of the glass tube 10. Furthermore, bringing the starting end 32 of the glass tube 10 into contact with at least one separation roller 326 may exert an axial tensile force F on the starting end 32 of the glass tube 10, which may separate the annular segment 30 from the glass tube 10. While transporting the annular segment 30 away from the glass tube 10, the method may include heating the target region 50 with a gas burner 322 to further reduce the viscosity of the target region 50 so that the axial tensile force F is sufficient to separate the annular segment 30 from the glass tube 10. Once the annular segment 30 is separated from the glass tube 10, the glass meniscus 21 is formed on the new end 34 of the glass tube 10.

[0146] Referring again to Figure 14, polishing the glass meniscus 21 at the new end 34 of the glass tube 10 may include flame polishing the glass meniscus 21 at the new end 34 of the glass tube 10 by exposing it to a gas burner 332. In this embodiment, polishing the glass meniscus 21 may modify the shape of the glass meniscus 21, thereby resulting in the outer surface 24 of the dome end glaze 20 having a radius of curvature r greater than 0.4 times d1 over a convex shape located at a distance of 0.4 times d1 from the central axis A of the glass tube 10. c Includes a convex shape having a certain characteristic.

[0147] In this embodiment, polishing the glass meniscus 21 can modify the shape of the glass meniscus 21, resulting in the outer surface 24 of the dome end glaze 20 having a radius of curvature r of approximately 0.5 times d1 over a convex shape located at a distance of 0.4 times d1 from the central axis A of the glass tube 10. c It includes a convex shape having a . In the embodiment, polishing the glass meniscus 21 can modify the shape of the glass meniscus 21, thereby the outer surface 24 of the resulting dome end glaze 20 having a radius of curvature r of 0.4 times d1 and 0.6 times d1 over a position on the convex shape within a distance of 0.4 times d1 from the central axis A of the glass tube 10. c It includes a convex shape having a . In the embodiment, polishing the glass meniscus 21 can modify the shape of the glass meniscus 21, thereby the outer surface 24 of the resulting dome end glaze 20 having a radius of curvature r of 0.3 times d1 and 0.7 times d1 over a position on the convex shape within a distance of 0.4 times d1 from the central axis A of the glass tube 10. c Includes a convex shape having a certain characteristic.

[0148] Referring here to Figure 15, a method for finishing one or more ends of the glass tube 10 may include forming vents 40 in the dome end glaze 20. Forming the vents 40 may include melting and opening the dome end glaze 20 at a position aligned with the central axis A of the glass tube 10. Melting and opening the dome end glaze 20 may include exposing the dome end glaze 20 to a vent burner 342, in particular to a flame produced by the vent burner 342.

[0149] Referring here to Figure 16, a method for finishing one or more ends of the glass tube 10 may include forming a glass meniscus 21 to modify the shape of the resulting dome end glaze 20. Forming the glass meniscus 21 may include bringing the glass meniscus 21 into contact with a forming tool 352 that reshapes the glass meniscus 21.

[0150] As discussed above with respect to System 100, the methods disclosed herein may include finishing the first end 17 and the second end 18 of the glass tube 10. In such embodiments, the method includes (i) removing a first annular segment of the glass tube 10 from a first starting end of the glass tube, wherein removing the first annular segment from the first starting end of the glass tube forms a first glass meniscus on the first new end of the glass tube; and (ii) removing a second annular segment of the glass tube 10 from a second starting end of the glass tube, wherein removing the second annular segment from the second starting end of the glass tube 10 forms a second glass meniscus on the second new end of the glass tube. The method may further include (i) polishing the first glass meniscus and the first new end of the glass tube to form a first dome end glaze at the first new end of the glass tube, and (ii) polishing the second glass meniscus and the second new end of the glass tube to form a second dome end glaze at the second new end of the glass tube. The resulting glass tube 10 comprises a first dome end glaze having a first outer surface having a first convex shape, and a second dome end glaze having a second outer surface having a second convex shape.

[0151] The glass tube 10 and corresponding system 100 and method disclosed herein offer a combination of valuable advantages to entities in the pharmaceutical packaging industry. On the tube manufacturing side, the system 100 and method disclosed herein offer improved manufacturing efficiency, at least in part, based on avoiding conventional cutting operations to final length and associated processes, as discussed above. For operators on the conversion side, the glass tube 10 having dome-shaped ends disclosed herein offers reduced tube damage associated with typical shipping and handling operations, improved conversion performance as a result of reduced tube damage, and reduced glass particles in stock glass tube material, which can improve the quality of converted glass articles.

[0152] Various embodiments of System 100 and methods for finishing the ends of glass tubes 10 using System 100 are described herein, but it should be understood that each of these embodiments and techniques may be used individually or in combination with one or more embodiments and techniques.

[0153] Those skilled in the art will see that various modifications and variations can be made to the embodiments described herein without departing from the spirit and scope of the claimed subject matter. Therefore, this specification is intended to encompass such modifications and variations, provided that they fall within the scope of the appended claims and their equivalents.

Claims

1. It is a glass tube, The first end and the second end, Equipped with glass, and with an outer diameter d １ It comprises a hollow cylindrical side wall having, The first end, the second end, or both are provided with a dome end glaze, the dome end glaze is provided with the glass and has a convex outer surface, The glass tube is d １ A glass tube having a longitudinal length L that is more than 30 times that of a standard glass tube.

2. The glass tube according to claim 1, wherein the longitudinal length L of the glass tube is 800 mm or more.

3. The convex shape of the outer surface of the dome end glaze is d from the central axis of the glass tube. １ Over the positions on the convex shape that are within a distance of 0.4 times the distance, d １ Radius of curvature r greater than or equal to 0.4 times ｃ A glass tube according to claim 1, comprising:

4. The radius of curvature r ｃ d from the central axis of the glass tube １ Over the positions on the convex shape that are within a distance of 0.4 times the distance, d １ The glass tube according to claim 3, wherein the ratio is 0.6 times or less.

5. The dome end glaze has a dome height H that is 0.4 times or more of d １ The glass tube according to claim 1, comprising a dome height H that is 0.4 times or more of d

6. The dome height H is d １ The glass tube according to claim 5, wherein the ratio is 0.6 times or less.

7. The glass tube according to claim 1, wherein the dome end glaze has a wall thickness that is less than or equal to the wall thickness of the hollow cylindrical side wall.

8. The glass tube according to claim 1, wherein the dome end glaze covers at least 75% of the cross-sectional area of ​​the glass tube at the first end, the second end, or both.

9. The glass tube according to claim 8, wherein the dome end glaze closes the glass tube at the first end of the glass tube, the second end of the glass tube, or both.

10. The glass tube according to claim 8, wherein the dome end glaze is provided with ventilation holes.

11. The glass tube according to claim 10, wherein the ventilation holes are aligned with the central axis of the glass tube.

12. The glass tube according to claim 10, wherein the center line of the ventilation hole forms an angle of less than 90 degrees, less than 70 degrees, or less than 45 degrees with respect to the central axis of the glass tube.

13. The glass tube according to claim 10, wherein the center line of the ventilation hole is not perpendicular to the central axis of the glass tube.

14. The aforementioned ventilation holes are, d １ 0.05 times to d １ The glass tube according to claim 10, having a diameter 0.20 times that of the glass tube.

15. The glass tube according to claim 1, wherein the glass tube is substantially free of end cracks and inclusions.

16. The glass tube according to claim 1, wherein the glass tube substantially does not contain glass particles fused to the outer and inner surfaces of the hollow cylindrical side wall.

17. The glass tube according to claim 1, wherein the dome end glaze comprises a first dome end glaze located at the first end of the glass tube and a second dome end glaze located at the second end of the glass tube.

18. A method for finishing the end of a glass tube, wherein the method is: Rotating the glass tube around its central axis, Removing the annular segment of the glass tube from the starting end of the glass tube, wherein removing the annular segment from the starting end of the glass tube forms a glass meniscus across the new end of the glass tube, The process includes polishing the glass meniscus at the new end of the glass tube in order to form a dome end glaze at the new end of the glass tube, wherein the dome end glaze has a convex outer surface. The glass tube is d １ It has a longitudinal length L that is 30 times longer than d １ The method wherein is the outer diameter of the glass tube.

19. The method according to claim 18, wherein the longitudinal length L of the glass tube is 800 mm or more.

20. The convex shape of the outer surface of the dome end glaze is d from the central axis of the glass tube. １ Over the positions on the convex shape that are within a distance of 0.4 times the distance, d １ Radius of curvature r greater than or equal to 0.4 times ｃ The method according to claim 18, comprising:

21. The radius of curvature r ｃ d from the central axis of the glass tube １ Over the positions on the convex shape that are within a distance of 0.4 times the distance, d １ The method according to claim 20, wherein the amount is 0.6 times or less.

22. The dome end glaze is d １ The method according to claim 18, wherein the dome height H is 0.4 times or more.

23. The dome height H is d １ The method according to claim 22, wherein the amount is 0.6 times or less.

24. Removing the annular segment from the starting end of the glass tube is, Heating the target region of the glass tube adjacent to the starting end of the glass tube, The method according to claim 18, comprising transporting the annular segment of the glass tube away from the glass tube in a direction parallel to the central axis of the glass tube.

25. The method according to claim 24, wherein heating the target region of the glass tube includes heating the glass tube in a circumferential direction as the glass tube rotates, and the target region is 50 mm or less from the starting end of the glass tube.

26. The method according to claim 24, wherein transporting the annular segment of the glass tube away from the glass tube includes bringing the starting end of the glass tube into contact with a roller having a roller rotation axis that forms an angle of 10 to 80 degrees with the central axis of the glass tube, and bringing the starting end of the glass tube into contact with the roller applies an axial tensile force to the starting end of the glass tube, and the axial tensile force separates the annular segment from the glass tube.

27. The method according to claim 18, wherein polishing the glass meniscus at the new end of the glass tube includes exposing the glass meniscus at the new end of the glass tube to a gas burner to flame polish the glass meniscus at the new end of the glass tube.

28. The method according to claim 18, wherein finishing the end of the glass tube produces a glass tube that is substantially free of end cracks and inclusions.

29. The method according to claim 18, wherein finishing the end of the glass tube produces a glass tube that is substantially free of glass particles fused to the outer or inner surface of the glass tube.

30. The method according to claim 18, further comprising forming ventilation holes in the dome end glaze.

31. The method according to claim 30, wherein forming the ventilation holes in the dome end glaze includes opening the dome end glaze at a position aligned with the central axis of the glass tube.

32. The method according to claim 30, wherein forming the ventilation holes in the dome end glaze includes exposing the dome end glaze to a ventilation hole burner to melt and open the dome end glaze.

33. The method according to claim 18, further comprising forming the meniscus to modify the convex shape of the dome end glaze.

34. The method according to claim 33, wherein forming the meniscus includes bringing the meniscus into contact with a forming tool for reshaping the meniscus.

35. The aforementioned method, Removing the first annular segment of the glass tube from the first starting end of the glass tube, wherein removing the first annular segment from the first starting end of the glass tube forms a first glass meniscus on the first new end of the glass tube, In order to form a first dome end glaze at the first new end of the glass tube, the first glass meniscus and the first new end of the glass tube are polished, Removing the second annular segment of the glass tube from the second starting end of the glass tube, wherein removing the second annular segment from the second starting end of the glass tube forms a second glass meniscus on the second new end of the glass tube, The process includes finishing the first and second ends of the glass tube by polishing the second glass meniscus and the second new end of the glass tube in order to form a second dome end glaze at the second new end of the glass tube. The method according to claim 18, wherein the first dome end glaze has a first outer surface having a first convex shape, and the second dome end glaze has a second outer surface having a second convex shape.

36. Before rotating the glass tube around its central axis, the method The method according to claim 18, further comprising receiving the glass tube from the tube manufacturing process.

37. A system for finishing the end of a glass tube, wherein the system is A conveyor configured to translate the glass tube and rotate the glass tube around its central axis, wherein the glass tube is d １ It has a longitudinal length L that is 30 times or more, where d １ This is the outer diameter of the glass tube, the conveyor and A separation station configured to remove an annular segment of a glass tube from its starting end, wherein removing the annular segment from the starting end of the glass tube forms a glass meniscus on the new end of the glass tube. A system comprising: a polishing station configured to form a glass meniscus at the new end of the glass tube in order to form a dome end glaze at the new end of the glass tube, wherein the dome end glaze has a convex outer surface;

38. The system according to claim 37, wherein the conveyor comprises a plurality of transport rollers configured to translate the glass tube in a direction perpendicular to the central axis of the glass tube.

39. The convex shape of the outer surface of the dome end glaze is d from the central axis of the glass tube. １ Over the positions on the convex shape that are within a distance of 0.4 times the distance, d １ Radius of curvature r greater than or equal to 0.4 times ｃ The system according to claim 37, comprising:

40. The radius of curvature r ｃ d from the central axis of the glass tube １ Over the positions on the convex shape that are within a distance of 0.4 times the distance, d １ The system according to claim 39, wherein it is 0.6 times or less.

41. The dome end glaze is d １ The system according to claim 37, comprising a dome height H of 0.4 times or more.

42. The dome height H is d １ The method according to claim 41, wherein the amount is 0.6 times or less.

43. The aforementioned separation station is One or more preheating stations configured to heat a target region of the glass tube adjacent to the starting end of the glass tube, The system according to claim 37, comprising: a pulling station configured to transport the annular segment of the glass tube away from the glass tube in a direction parallel to the central axis of the glass tube.

44. The system according to claim 43, wherein each of the one or more preheating stations comprises a gas burner configured to heat the target region of the glass tube in a circumferential direction as the glass tube rotates.

45. The system according to claim 43, wherein the target area is 50 mm or less from the starting end of the glass tube.

46. The aforementioned pulling station is An end support roller configured to support the starting end of the glass tube, The system according to claim 43, comprising: a separation roller configured to apply an axial tensile force to the starting end of the glass tube, wherein the axial tensile force separates the annular segment from the glass tube;

47. The system according to claim 46, wherein the separating roller has a roller rotation axis that forms an angle of 10 to 80 degrees with the central axis of the glass tube.

48. The system according to claim 37, wherein the polishing station comprises a gas burner configured to flame polish the glass meniscus at the new end of the glass tube.

49. The system according to claim 37, wherein the end of the glass tube is finished such that the glass tube is substantially free of end cracks and inclusions.

50. The system according to claim 37, wherein the glass tube is configured such that the end of the glass tube is finished so as not to contain substantially any glass particles fused to the outer or inner surface of the glass tube.

51. The system according to claim 37, further comprising a ventilation station configured to form ventilation holes in the dome end glaze.

52. The system according to claim 51, wherein the ventilation station comprises a ventilation burner configured to melt and open the dome end glaze to form the ventilation holes.

53. The system according to claim 37, further comprising a forming station configured to modify the convex shape of the dome end glaze.

54. The system according to claim 53, wherein the forming station comprises a forming tool configured to reshape the meniscus.

55. The aforementioned separation station is Removing the first annular segment of the glass tube from the first starting end of the glass tube, wherein removing the first annular segment from the first starting end of the glass tube forms a first glass meniscus on the first new end of the glass tube, The removal of the second annular segment of the glass tube from the second starting end of the glass tube is configured to form a second glass meniscus on the second new end of the glass tube, and the removal of the second annular segment from the second starting end of the glass tube is configured to form a second glass meniscus on the second new end of the glass tube, The aforementioned polishing station is In order to form a first dome end glaze at the first new end of the glass tube, the first glass meniscus and the first new end of the glass tube are polished, The system is configured to polish the second glass meniscus and the second new end of the glass tube in order to form a second dome end glaze at the second new end of the glass tube, The system according to claim 37, wherein the first dome end glaze has a first outer surface having a first convex shape, and the second dome end glaze has a second outer surface having a second convex shape.

56. The system according to claim 37, wherein the conveyor is configured to receive the glass tubes from the tube manufacturing process.

57. The system according to claim 37, wherein the longitudinal length L of the glass tube is 800 mm or more.

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