Method and apparatus for controlling thermal variations during tube consumption in glass tube conversion

Abstract

A method for manufacturing an article from a glass tube includes securing a working end of the glass tube in a glass tube holder of a converter having multiple processing stations, including a heating station and a forming station. The initial length of the glass tube includes multiple successive segments, each of which corresponds to an article and has an article number. The method includes heating the working end of the glass tube in the heating station, adjusting the amount of heat applied to the glass tube in the heating station based on the article number at the working end of the glass tube, and forming features of the article in the forming station. Adjusting the amount of heat applied based on the article number reduces variation in tube temperature, product dimensions, or both from one article number to the next.

Description

Related Applications

[0001] This application claims the benefit of priority under 35 U.S.C. § 119 to U.S. Provisional Application No. 63 / 066,475, filed August 17, 2020, the contents of which are relied upon and incorporated herein by reference in their entirety. [Technical Field]

[0002] FIELD OF THE INVENTION The present disclosure relates generally to systems and methods for producing glass articles from glass tubes, and more particularly to systems and methods for reducing temperature and dimensional variations during the glass tube conversion process. [Background technology]

[0003] Historically, glass has been the preferred material for packaging pharmaceuticals due to its hermeticity, optical clarity, and superior chemical durability relative to other materials. Specifically, glass used in pharmaceutical packaging must have adequate chemical durability to prevent any impact on the stability of the pharmaceutical formulation contained within. Glasses with adequate chemical durability include those within the ASTM standard "Type IA" and "Type IB" glass compositions, which have a proven track record of chemical durability.

[0004] Glass tubing can be converted into other glass articles, such as various glass containers for use in pharmaceutical applications, including, but not limited to, vials, syringes, ampoules, cartridges, and other glass articles. Glass tubing can be converted, for example, in a "converting machine." Converting machines have been in use for over 75 years and are currently manufactured by various commercial and internal equipment suppliers. These converting machines typically convert lengths of glass tubing into multiple glass articles using steps that include flame processing, rotary and stationary tool forming, thermal separation, or scoring and impact cutting. A series of burners is often used to separate sections or segments from the glass tubing and form them to specific dimensions. Summary of the Invention [Problem to be solved by the invention]

[0005] During the converting process, the temperature of a length of glass tubing loaded into a converting machine can vary as the glass tubing is consumed through multiple passes through the converting process. These temperature variations in the length of glass tubing can lead to variations in the dimensions and appearance of glass articles made from the glass tubing. Therefore, there is a need for a system and method that reduces glass tubing temperature variations as the glass tubing is gradually consumed during the converting process while converting the glass tubing into glass articles, such as pharmaceutical packages. [Means for solving the problem]

[0006] In a first aspect of the present disclosure, a method for manufacturing multiple articles from a glass tube may include securing a working end of the glass tube in a glass tube holder of a converter having multiple processing stations, including at least one heating station and at least one forming station subsequent to the at least one heating station. The converter may move the glass tube holder through the multiple processing stations. The initial length of the glass tube may include multiple successive segments, each of the multiple successive segments corresponding to an article and having an article number. The method may further include heating the working end of the glass tube in at least one heating station and increasing or decreasing the amount of heating of the glass tube based on the article number corresponding to the working end of the glass tube. Increasing or decreasing the amount of heating based on the article number may reduce variation in tube temperature, article dimensions, or both from a given article number to the next. The method may further include forming at least one feature of the article on the working end of the glass tube at at least one forming station, separating the article from the working end of the glass tube at a separation station, and indexing the glass tube downward in the glass tube holder to form the next article.

[0007] A second aspect of the present disclosure may include the first aspect, wherein the step of increasing or decreasing the amount of heating of the glass tube may include at least one of the following steps: increasing or decreasing a burner residence time of the working end of the glass tube in contact with a heating element in at least one heating station based on an item number at the working end of the glass tube; increasing or decreasing a heating rate of a heating element in at least one heating station based on an item number at the working end of the glass tube; or adjusting a negative pressure generated by an exhaust system proximate to the glass tube in at least one heating station based on an item number at the working end of the glass tube.

[0008] A third aspect of the present disclosure may include the first or second aspect, wherein the multiple processing stations may include multiple heating stations, and the method may include increasing or decreasing the amount of heating of the glass tube at each of the multiple heating stations based on an item number corresponding to the working end of the glass tube.

[0009] A fourth aspect of the present disclosure may include any one of the first through third aspects, wherein the variation in tube temperature, article size, or both at the working end of the glass tube may be a function of an article number of the article formed at the working end of the glass tube.

[0010] A fifth aspect of the present disclosure may include any one of the first to fourth aspects, wherein the step of increasing or decreasing the amount of heating at the working end of the glass tube may include the step of increasing or decreasing a burner residence time of the glass tube in contact with a heating element in at least one heating station based on an item number at the working end of the glass tube.

[0011] A sixth aspect of the present disclosure may include the fifth aspect, wherein the heating element in at least one heating station may comprise a swirl burner that may swirl to engage or disengage the working end of the glass tube.

[0012] A seventh aspect of the present disclosure may include the sixth aspect, wherein increasing or decreasing the burner residence time may include adjusting the timing of the swirl burner to swirl into or out of engagement with the working end of the glass tube.

[0013] An eighth aspect of the present disclosure may include any one of the first to seventh aspects, wherein the step of increasing or decreasing the amount of heating of the working end of the glass tube may include the step of increasing or decreasing a heating rate of a heating element in at least one heating station based on an item number of the working end of the glass tube.

[0014] A ninth aspect of the present disclosure may include the eighth aspect, wherein the heating element may include a burner, and increasing or decreasing the heating rate may include increasing or decreasing a flow rate of one or more combustion gases supplied to the burner. The combustion gases may include a fuel gas and oxygen, air, or both.

[0015] A tenth aspect of the present disclosure may include the ninth aspect, wherein increasing or decreasing the heating rate may include proportionally increasing or decreasing the flow rate of all combustion gases to the burner.

[0016] An eleventh aspect of the present disclosure may include the ninth aspect, wherein increasing or decreasing the heating rate may include modifying a flow ratio of fuel gas to oxygen supplied to the burner.

[0017] A twelfth aspect of the present disclosure may include any one of the first to eleventh aspects, wherein the step of increasing or decreasing the amount of heating at the working end of the glass tube may include adjusting the negative pressure generated by an exhaust system proximate to at least one heating station based on the item number of the working end of the glass tube.

[0018] A thirteenth aspect of the present disclosure may include the twelfth aspect, wherein adjusting the negative pressure generated by the exhaust system proximate to the at least one heating station may include decreasing or increasing a speed of an air handler fluidly connected to an inlet vent positioned proximate to the at least one heating station, adjusting a position of a damper disposed between the air handler and the inlet vent, or both.

[0019] A fourteenth aspect of the present disclosure may include the twelfth aspect, wherein adjusting the negative pressure generated by the exhaust system proximate to the at least one heating station may include adjusting a position of an inlet vent of the exhaust system relative to the glass tube in the at least one heating station.

[0020] A fifteenth aspect of the present disclosure may include any one of the first to fourteenth aspects, wherein the converter may include a plurality of glass tube holders, and the method may include the steps of moving each of the plurality of glass tube holders through each of a plurality of processing stations, and increasing or decreasing the amount of heating at the working end of the glass tube based on the item number each time the plurality of glass tube holders move to the next processing station.

[0021] A sixteenth aspect of the present disclosure may include any one of the first to fourteenth aspects, further including a step of securing a new length of glass tube within the tube holder after the last item corresponding to the last item number of the glass tube is manufactured.

[0022] A seventeenth aspect of the present disclosure may include the sixteenth aspect, wherein the converter may include a plurality of glass tube holders, and the method may further include a step of securing a new length of glass tube to each of the plurality of glass tube holders in consecutive order, starting with a first glass tube.

[0023] An eighteenth aspect of the present disclosure may include the seventeenth aspect, including the steps of: varying the amount of heating at the working end of the first glass tube based on the item number in response to a change in the item number at the working end of the first glass tube at the at least one heating station; and maintaining the amount of heating at the at least one heating station from glass tube to glass tube until the first glass tube returns to the at least one heating station and the item number at the working end of the first glass tube changes.

[0024] In a nineteenth aspect of the present disclosure, a method for manufacturing multiple articles from a glass tube may include introducing the glass tube into a glass tube holder of a converter having multiple processing stations, including at least one heating station and at least one forming station subsequent to the at least one heating station. The converter may move the glass tube holder through the multiple processing stations. The method may further include heating a working end of the glass tube at at least one heating station and forming at least one feature of a first article on the working end of the glass tube at at least one forming station, the first article corresponding to a first sequential position along the length of the glass tube. The method may further include separating the first article from the working end of the glass tube at a separation station and, after separation, indexing the glass tube downward within the glass tube holder to form a second article from the glass tube, the second article corresponding to a second sequential position along the length of the glass tube. The method may further include heating a working end of the glass tube corresponding to the second sequential position in at least one heating station, and increasing or decreasing the amount of heating of the glass tube corresponding to the second sequential position relative to the heating of the first article. Increasing or decreasing the amount of heating of the working end of the glass tube of the second article relative to the first article may reduce the variability in temperature or dimension of the second article relative to the first article.

[0025] In a twentieth aspect of the present disclosure, a system for manufacturing multiple articles from a glass tube may include a converter including multiple processing stations, including at least one heating station, at least one forming station, and a separation station. The converter may be operable to move the glass tube through the multiple processing stations. The system may further include a system controller communicatively connected to the converter. The system controller may include a processor and a storage medium including computer-readable and executable instructions, which, when executed by the processor, may cause the system controller to automatically determine an item number at a working end of the glass tube, the item number including integers corresponding to consecutive segments of an initial length of the glass tube, each consecutive segment corresponding to an article, and increase or decrease the amount of heating of the glass tube at the at least one heating station based on the item number at the working end of the glass tube.

[0026] A twenty-first aspect of the present disclosure may include the twentieth aspect, wherein at least one heating station may include a swirl burner operable to swirl into and out of engagement with the working end of the glass tube, and the system controller may be communicatively connected to the swirl burner.

[0027] A twenty-second aspect of the present disclosure may include the twentieth or twenty-first aspect, wherein the computer-readable and executable instructions, when executed by a processor, may cause a system controller to automatically increase or decrease a burner residence time at the working end of the glass tube based on an item number at the working end of the glass tube by pivoting the swirl burner into or out of engagement with the working end of the glass tube.

[0028] A 23rd aspect of the present disclosure may include any one of the 20th to 22nd aspects, wherein the at least one heating station may include at least one burner and at least one flow controller that may be operable to increase or decrease a mass flow rate of one or more combustion gases to the at least one burner.

[0029] A twenty-fourth aspect of the present disclosure may include the twenty-third aspect, wherein the computer-readable and executable instructions, when executed by a processor, may cause a system controller to automatically increase or decrease the mass flow rate of one or more combustion gases to the at least one burner based on an item number at the working end of the glass tube.

[0030] A 25th aspect of the present disclosure may include any one of the 20th to 24th aspects, wherein the converter may include an exhaust system including at least one inlet vent and an air handler fluidly connected to the at least one inlet vent.

[0031] A twenty-sixth aspect of the present disclosure may include the twenty-fifth aspect, wherein the computer-readable and executable instructions, when executed by a processor, may cause a system controller to automatically adjust the negative pressure generated by an exhaust system proximate to the glass tube based on an item number at the working end of the glass tube.

[0032] It is to be understood that both the foregoing general description and the following detailed description describe various embodiments and are intended 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 into and constitute a part of this specification. The drawings illustrate various embodiments described herein and, together with the description, serve to explain the principles and operation of the claimed subject matter. [Brief explanation of the drawings]

[0033] [Figure 1] FIG. 1A is a schematic diagram illustrating an embodiment of a converter for producing glass articles from glass tubes according to one or more embodiments shown and described herein. [Figure 2]2A-2C are schematic diagrams illustrating top views of the main turret, secondary turret, and feed turret of the converter of FIG. 1 according to one or more embodiments shown and described herein. [Figure 3A] 2 is a schematic diagram of a heating station of the converter of FIG. 1 according to one or more embodiments shown and described herein. [Figure 3B] 2 is a schematic diagram of a forming station for the transducer of FIG. 1 according to one or more embodiments shown and described herein. [Figure 3C] 2 is a schematic diagram of another embodiment of a forming station for the transducer of FIG. 1 in accordance with one or more embodiments shown and described herein. [Figure 3D] 2 is a schematic diagram of a cooling station of the converter of FIG. 1 according to one or more embodiments shown and described herein. [Figure 3E] 2 is a schematic diagram of a separation station of the converter of FIG. 1 according to one or more embodiments shown and described herein. [Figure 3F] 2 is a schematic diagram of a drilling station of the transducer of FIG. 1 according to one or more embodiments shown and described herein. [Figure 4] FIG. 2 schematically illustrates a perspective view of a glass tube prior to conversion with the converter of FIG. 1 according to one or more embodiments shown and described herein. [Figure 5] FIG. 1 is a graphical representation of feature dimensions of glass vials (y-axis) as a function of product number (x-axis) manufactured without correction for thermal variability of the glass tubes. [Figure 6] 2 is a schematic diagram of another heating station of the converter of FIG. 1 according to one or more embodiments shown and described herein. [Figure 7A] 7 is a diagram illustrating a schematic top view of the swirl burner of the converter of FIG. 1 in a position to engage a glass tube in the heating station of FIG. 6 according to one or more embodiments shown and described herein. [Figure 7B]7 is a diagram illustrating a schematic top view of the swirl burner of the converter of FIG. 1 in a position not engaging the glass tube in the heating station of FIG. 6 according to one or more embodiments shown and described herein. [Figure 8] FIG. 7 graphically illustrates glass article dimensions (y-axis) as a function of article number (x-axis) with and without varying burner residence time within the heating station of FIG. 6, according to one or more embodiments shown and described herein. [Figure 9] FIG. 8 graphically illustrates glass tube temperature (y-axis) as a function of time (x-axis) during burner residence time within the heating station of FIG. 7, according to one or more embodiments shown and described herein. [Figure 10A] FIG. 1 is a graph of article size (y-axis) as a function of article number (x-axis) without correction for thermal variability of the glass tube during conversion. [Figure 10B] FIG. 7 is a graphical illustration of article size (y-axis) as a function of article number (x-axis) adjusted for the heating rate of the burner in the heating station of FIG. 6, according to one or more embodiments shown and described herein. [Figure 11] 2 is a schematic diagram of another heating station of the converter of FIG. 1 according to one or more embodiments shown and described herein. [Figure 12] FIG. 2 is a graphical illustration of article size (y-axis) as a function of article number (x-axis) at various exhaust flow velocities according to one or more embodiments shown and described herein. DETAILED DESCRIPTION OF THE INVENTION

[0034] Reference will now be made in detail to embodiments of systems and methods for reducing temperature and dimensional variations in glass articles produced based on a converting process for converting glass tubing into glass articles, examples of which are illustrated in the accompanying drawings. Wherever possible, identical reference numerals are used throughout the drawings to refer to identical or similar parts. Glass tubing can be converted into glass articles, particularly glass articles for use in pharmaceutical applications, which may include, but are not limited to, vials, syringes, ampoules, cartridges, and other glass articles. Glass tubing can be converted into these glass articles using a converting machine, such as a converting machine, that includes multiple processing stations. The processing stations may include heating stations, forming stations, thermal separation stations, and perforation stations, among other types of processing stations. Converting machines typically convert lengths of long glass tubing into multiple glass articles using steps including, but not limited to, flame processing, rotary and stationary tool forming, thermal separation, or scoring and impact cutting. Thus, glass articles produced by the converting process performed in the converting machine are subjected to a series of flame burners or other heating elements to separate portions from the glass tubing and form them to specific dimensions.

[0035] During the conversion process, glass tubes are loaded into the conversion machine at room temperature (approximately 23°C). However, the temperature of the non-working portion of the glass tube can rise to over 200°C during consumption due to heat emitted by the flame burners in the converter or conversion machine. As the glass tube is fully consumed, the shortened length of the glass tube increases the gas flow rate through the tube, which can also affect the glass tube temperature. Changes in glass tube temperature during processing and consumption can result in dimensional and appearance variations in the glass articles formed during the conversion process. Variations in glass tube temperature and the resulting dimensional and appearance variations can constrain the operating window of the conversion process, reducing process capability (Cpk) and reducing yield. Yield reduction can result from reduced production rates or yield losses due to dimensional and appearance variations that cause articles to be out of specification. For certain SKU numbers run under certain process conditions, yield loss due to dimensional and cosmetic variations can exceed 30%, and at least a portion of this yield loss can be attributed to variations in glass tube temperature during conversion.

[0036] Various solutions have been proposed to reduce the temperature variability of glass tube stock as it is consumed, but it has not been proven that they are sufficient to reduce the dimensional and appearance variability caused by variations in glass tube temperature as it is consumed. For example, some operators preheat glass tubes on a tube carousel or above the converting machine before loading them into the converting machine. This method is not feasible in current converting processes because the tube loader is constructed of plastic to avoid metal-to-glass contact, and preheating the glass tube to a temperature sufficient to reduce thermal variability would deform the tube loader's plastic. In another proposed solution, the glass tube is closed or closed and vented, preventing heated gas from flowing through the tube's central cavity. However, closed or closed and vented glass tubes require specialized forming equipment on the converting machine and, even if implemented, do not eliminate the thermal variability of the process.

[0037] Thus, there remains a need for systems and methods for converting glass tubing into glass articles, such as pharmaceutical packages, while reducing variations in glass tubing temperature as the glass tubing is gradually consumed by the conversion process. The systems and methods of the present disclosure are directed to adjusting the amount of heating of the glass tubing based on the item number at the working end of the glass tubing to compensate for temperature variations along the length of the glass tubing as it is consumed. The amount of heating of the glass tubing can be managed on an item-by-item basis and / or on a main turret rotation basis as the glass tubing is consumed.

[0038] The initial length of glass tubing can be conceptually divided into multiple consecutive segments, each corresponding to an item and associated with an item number. Starting with the first item made from glass tubing assigned item number 1, the temperature of each successive segment changes as the item number increases. Using a relational database that tracks the item numbers at the working end of the glass tubing, a controller can be used to control the burner residence time, burner power / heat rate, or exhaust flow on an item-by-item basis to regulate the tube temperature to more "steady state" conditions.

[0039] An embodiment of a system for producing articles from glass tubes is shown in Figure 1. In the embodiment shown in Figure 1, the system for producing glass articles from glass tubes 102 includes a converter 100 having multiple processing stations 106, including at least one heating station, at least one forming station, and a separation station. The converter 100 is operable to move the glass tube 102 through the multiple processing stations 106. Referring to Figure 5, the system may include a system controller 400 (Figure 5) communicatively connected to the converter 100. The system controller 400 may be operable to determine an item number at the working end 150 of the glass tube 102 and increase or decrease the amount of heating of the glass tube 102 in at least one heating station 202 based on the item number at the working end 150 of the glass tube 102.

[0040] A method for producing multiple articles from a glass tube 102 may include securing a working end 150 of the glass tube 102 to a glass tube holder 130 of a converter 100 having multiple processing stations 106. The processing stations 106 may include at least one heating station and at least one forming station subsequent to the at least one heating station. The converter 100 moves the glass tube holder 130 and the glass tube 102 secured within the glass tube holder 130 through the multiple processing stations 106. The initial length of the glass tube comprises multiple successive segments, each of which corresponds to an article and has an article number. The method may include heating the working end 150 of the glass tube 102 at at least one heating station 202, increasing or decreasing the amount of heating of the glass tube 102 based on an item number corresponding to the working end 150 of the glass tube 102, forming at least one feature of the item on the working end 150 of the glass tube 102 at at least one forming station, separating the item from the working end 150 of the glass tube 102 at a separation station, and indexing the glass tube 102 downward within the glass tube holder 130 to form the next item.

[0041] Increasing or decreasing the amount of heat based on the item number can reduce the variation in tube temperature, item size, or both from a given item number to the next. Controlling the amount of heat applied to the glass tube based on the item number at the working end of the glass tube can allow for greater granularity in the control scheme and reduce process variability by vial number. This can widen the process window of the conversion process and reduce out-of-specification items. Therefore, among other features, yield from the conversion process can be increased by reducing yield loss and increasing production rate. It should be understood that various aspects of the systems and methods disclosed herein are described in the context of a conversion process for manufacturing pharmaceutical vials. However, it should be understood that the systems and methods may be applied to conversion processes for manufacturing other items, such as, but not limited to, cartridges, syringes, ampoules, etc.

[0042] Directional terms used herein, such as up, down, right, left, front, back, top, and bottom, are used solely with reference to the illustrated figures and their associated coordinate axes and are not intended to imply absolute orientation.

[0043] Unless expressly stated otherwise, it is in no way intended that methods described herein be construed as requiring that their steps be performed in a particular order, nor that a particular orientation be required of any apparatus. Thus, where a method claim does not actually recite an order that its steps must be followed, or an apparatus claim does not actually recite an order or orientation for individual components, or where a claim or description does not specifically otherwise state that the steps are limited to a particular order, or where no particular order or orientation for the apparatus components is recited, no order or orientation is intended to be inferred in any respect. This applies to possible implicit bases for interpretation, including matters of logic, plain meaning derived from grammatical construction or punctuation, and the number or type of embodiments set forth in the specification, regarding the organization of steps, flow of operations, order of components, or orientation of components.

[0044] As used herein, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to "a" component includes aspects having two or more such components unless the context clearly dictates otherwise.

[0045] As used herein, the "working end" of the glass tube is the end of the glass tube oriented relative to the holder toward the processing station of the converter, and the "non-working end" of the glass tube is the end of the glass tube oriented away from the processing station.

[0046] As used herein, the "dwell time" of a transducer refers to the duration of time that a glass tube spends at a particular processing station before being moved to the next subsequent processing station.

[0047] As used herein, "burner residence time" refers to the duration that the burner flame engages or acts on the glass tube and the glass tube is heated.

[0048] Referring now to FIG. 1 , a converter 100 for producing glass articles from glass tubes 102 is shown schematically. The converter 100 can be used to convert the glass tubes 102 into multiple glass articles, such as, but not limited to, vials, syringes, cartridges, ampoules, or other glass articles. The converter 100 includes a base 104 having multiple processing stations 106 and a main turret 108 positioned above the base 104 and rotatable relative to the base 104 about a central axis A. The converter 100 may further include a glass tube loading turret 110 positioned above the main turret 108, into which the glass tubes 102 are fed. The converter 100 may also include multiple secondary processing stations 112 on the base 104 and a secondary turret 114 rotatable relative to the base 104.

[0049] As shown generally in FIG. 1 , the base 104 of the converter 100 is stationary, and the processing stations 106 can be coupled to an upper portion 105 of the base 104. The multiple processing stations 106 are spaced apart from one another and arranged within a main circuit 116. In one or more embodiments, the main circuit 116 can be circular, and the main turret 108 can move the glass tubes 102 through the multiple processing stations 106 by rotating the main turret 108 about a central axis A. Alternatively, in other embodiments, the main circuit 116 can be linear. While described herein with reference to a circular layout of the processing stations 106, it should be understood that the subject matter disclosed herein may apply to converters having other arrangements of the processing stations 106 as well.

[0050] The type and / or shape of the article to be produced from the glass tube 102 may affect the number of processing stations 106 coupled to the base 104. The number of processing stations 106 in the main turret 108 may be between 14 and 32 processing stations 106. While the converter 100 and converting process are described herein in the context of a converter 100 having 16 processing stations 106 in the main circuit 116, it should be understood that the converter 100 may have more or fewer than 16 processing stations 106 in the main circuit 116. The processing stations 106 may include, by way of example and not limitation, one or more heating, forming, polishing, cooling, separating, drilling, measuring, feeding, or ejecting stations, or other processing stations, at which the glass article is produced from the glass tube 102. The type and / or shape of the article to be produced from the glass tube 102 may also affect the type and / or order of the processing stations 106 in the converter 100.

[0051] The main turret 108 can be positioned above the base 104 and rotatably coupled to the base 104, allowing the main turret 108 to rotate about a central axis A relative to the base 104. A drive motor (not shown) can be utilized to rotate the main turret 108 relative to the base 104. The main turret 108 includes a plurality of holders 130 configured to removably secure each glass tube 102 to the main turret 108. The holders 130 can be clamps, chucks, or other holding devices, or a combination of holding devices. The holders 130 can orient each glass tube 102 so that the glass tube 102 is approximately parallel to the central axis A of the main turret 108 and approximately perpendicular to the upper portion 105 of the base 104. While the transducer 100 is described herein in the context of a vertically oriented transducer 100, it should be understood that the transducer 100 may also be oriented horizontally or at an angle. Each of the holders 130 extends from the bottom portion 109 of the main turret 108 toward the base 104 (i.e., the −Z direction relative to the coordinate axes of FIG. 1 ), and each holder 130 is oriented to position the glass tube 102 at or adjacent to each of successive processing stations 106 of the main circuit 116 of the base 104 as the main turret 108 is indexed about the central axis A. The vertical orientation of the glass tubes 102 allows the downwardly protruding portion of each glass tube 102 to be cycled progressively through the processing stations 106 of the main circuit 116. In embodiments, the converter 100 may be operable to index each of the multiple holders 130 progressively through the multiple processing stations 106. Alternatively, in embodiments, the converter 100 may be operable to translate the multiple holders 130 continuously through the conversion process. Each holder 130 may be individually rotatable about a holder axis D relative to the main turret 108 , and the holder axis D may be substantially parallel to the central axis A of the main turret 108 .Each of the holders 130 may be operably coupled to a motor (not shown), continuous drive belt, or other drive mechanism for rotating each of the holders 130 relative to the main turret 108. Rotation of the holders 130 allows the glass tube 102 to rotate relative to a stationary burner, forming tool, cooling nozzle, or other feature of the processing station 106.

[0052] 1 and 2, the converter 100 may have a plurality of secondary processing stations 112 spaced apart within a secondary circuit 118 (FIG. 2), and a secondary turret 114 (FIG. 1) for indexing an article 103 (FIG. 1) separated from a glass tube 102 through the plurality of secondary processing stations 112. The secondary turret 114 may be rotatable about a second axis B relative to the base 104. The second axis B may be substantially parallel to the central axis A of the main turret 108. The secondary turret 114 also includes a plurality of holders 130 for holding the glass articles 103 and positioning the glass articles 103 for sequential engagement with each of the secondary processing stations 112. The secondary turret 114 can receive the article 103 from the separation station 206 (FIG. 2) of the main turret 108, index the article 103 through multiple secondary processing stations 112 by rotation of the secondary turret 114, and eject the completed article from the converter 100.

[0053] The glass tube loading turret 110 may be positioned above the main turret 108. In embodiments, the glass tube loading turret 110 may be offset from a central axis A of the main turret 108. The glass tube loading turret 110 may be rotatable about an axis C, which may be substantially parallel to the central axis A of the main turret 108. The glass tube loading turret 110 may be independently supported in a stationary position relative to the main turret 108, and the rotation of the glass tube loading turret 110 may be independent of the rotation of the main turret 108. Referring to FIGS. 1 and 2 , in some embodiments, the glass tube loading turret 110 may include a plurality of loading passages 132 arranged in a circular circuit 134 and configured to hold the glass tubes 102. The glass tube loading turret 110 can be positioned to vertically align one of the loading passages 132 with a processing station 106 of the main circuit 116 of the converter 100 and a corresponding holder 130 on the main turret 108 that is indexed through the processing station 106 of the main circuit 116 (i.e., in a direction parallel to the central axis A of the main turret 108 and / or in a direction parallel to the Z-axis in FIG. 1 ). In one or more embodiments, the processing station 106 aligned with the glass tube loading turret 110 can be a tube loading station 214 ( FIG. 2 ). When converter 100 has converted all or at least a portion of glass tube 102 into one or more articles at a particular holder position 136, glass tube loading turret 110 can deliver a new length of glass tube 102 through the top of main turret 108 to holder 130 at holder position 136, which is indexed to align with tube loading station 214 ( FIG. 2 ) of main circuit 116. In an alternative embodiment, converter 100 may include an arm (not shown) movable between main turret 108 and glass tube loading turret 110.Once the converter 100 has converted all or a portion of the glass tube 102 at a particular holder position 136, the arm can grab a new length of glass tube 102 from the glass tube loading turret 110 or other glass tube staging device and deliver the new length of glass tube 102 to the main turret 108 at the particular holder position 136. Other methods and devices for delivering the new length of glass tube 102 to the main turret 108 are contemplated.

[0054] Referring to FIG. 2, as previously described, the multiple processing stations 106 of the converter 100 may include one or more heating stations 202, forming stations 204, separating stations 206, cooling stations 210, punching stations 212, tube loading stations 214, ejection stations 216, measuring stations 218, tube length dropping stations 220, or other stations and / or combinations of these stations. FIG. 2 schematically illustrates a processing station 106 configuration of the converter 100 having a main circuit 116 of 16 processing stations 106 and a secondary circuit 118 of eight secondary processing stations 112. As previously described, the processing stations 106 of the main circuit 116 are equally spaced around the circular circuit, and the secondary processing stations 112 of the secondary circuit 118 are also equally spaced around the circular circuit. FIG. 2 also schematically illustrates a glass tube loading turret 110 having multiple loading passages 132. 2, the glass tube loading turret 110 is shown in a position spaced apart from the main circuit 116 for purposes of illustration. Although the glass tube loading turret 110 is shown as having 24 loading passages 132, it should be understood that the glass tube loading turret may have more or less than 24 loading passages 132.

[0055] The converter's main circuit 116, shown schematically in FIG. 2, may include one or more heating stations 202, a separation station 206, a piercing station 212, one or more forming stations 204, one or more cooling stations 210, a measuring station 218, a tube length drop station 220, and a tube loading station 214. While the main circuit 116 is shown in FIG. 2 as having a circular arrangement of processing stations 106, as previously described, the main circuit 116 may have processing stations 106 positioned in other geometric arrangements, such as linear, polygonal, or other arrangements. With respect to the indexing direction 222 of the main turret 108, a heating station 202 may be positioned before the separation station 206 and each forming station 204 to preheat a target region of the glass tube 102 to a target temperature at which the target region of the glass tube 102 becomes viscous and deformable, effectively allowing it to be shaped or stretched and separated. At the separation station 206, the formed glass article 103 (FIG. 1) can be separated from the glass tube 102 (FIG. 1) as the bottom of the glass article 103 is simultaneously formed. The separation station 206 can also be the processing station 106, where the partially formed glass article 103, once separated, is transferred to the secondary turret 114 (FIG. 1) and indexed through the secondary circuit 118 of the secondary processing station 112. The piercing station 212 can be positioned on the main circuit 116 downstream from the separation station 206 in the index direction 222 of the main turret 108. At the piercing station 212, the meniscus 350 of the glass tube 102 previously formed at the separation station 206 is pierced, thereby reopening the working end 150 of the glass tube 102.

[0056] The forming stations 204 of the main turret 108 can be positioned downstream of the punching station 212 in the index direction 222. At the forming stations 204, the glass tube 102 is repeatedly formed into the desired shape of the finished glass article. As described above, one or more heating stations 202 can be positioned before each forming station 204, where a target area of ​​the glass tube 102 is preheated to a temperature at which the glass tube 102 can be formed. The forming stations 204 of the main turret 108 form the working end 150 ( FIG. 3A ) of the glass tube 102 to form one end of the glass article 103, and the forming stations 204 of the secondary turret 114 form the other end of the glass article 103 after the glass article 103 is separated from the glass tube 102. In an embodiment, vials can be produced from glass tubes 102 using the converter 100, and the forming stations 204 of the converter 100 can include one or more shoulder-forming stations, one or more flange-forming stations, and one or more flange-finishing stations, with one or more heating stations 202 positioned before and between each of the forming stations 204. The main circuit 116 can further include a measuring station 218, which can use a dimensional measurement system (not shown) to measure one or more dimensions of the glass tube 102, such as diameter and thickness, and one or more dimensions of features formed by the forming stations 204. The feature dimensions can include flange thickness, flange length, neck length, neck thickness, overall article length, other feature dimensions, or combinations thereof. The measuring station 218 can be positioned immediately after the last forming station 204, allowing dimensions to be measured while the glass tube 102 is still hot. Alternatively, the measurement station 218 can be positioned after one or more cooling stations 210, where the dimensions of the glass tube 102 and / or the glass article dimensions are measured at a lower temperature.

[0057] 2 , one or more cooling stations 210 can be positioned after the forming stations 204 in the index direction 222 of the main turret 108. A tube length drop station 220 can be positioned after the forming stations 204, between the forming stations 204 and the separation station 206, with the glass tube 102 positioned so that the partially formed glass tube 102 drops, thereby separating the glass article 103 from the glass tube 102 at the separation station 206. The main circuit 116 can also include a tube loading station 214 for loading a new glass tube 102 length feed from the glass tube loading turret 110 into the main turret 108 ( FIG. 1 ). In one or more embodiments, the tube loading station 214 can be incorporated into the cooling station 210. The tube loading station 214 can be positioned between the last forming station 204 and the separation station 206.

[0058] The forming stations 204 of the main turret 108 can form features on a first end of the glass article 103. For example, the forming stations 204 can form a shoulder 142 and a flange 144 on the top (first end) of the glass article 103, which is a vial or cartridge. Once the glass article 103 is separated from the glass tube 102 at the separation station 206, the glass article 103 is transferred to a secondary processing station 112 of the secondary turret 114. The secondary processing station 112 can include one or more forming stations 204, where a second end of the glass article 103 is formed, the second end being opposite the first end of the glass article 103. For example, the forming stations 204 of the secondary processing stations 112 can form one or more features on the bottom (second end) of the glass article 103.

[0059] The secondary processing stations of the secondary circuit may include one or more heating stations 202, forming stations 204, polishing stations 208, cooling stations 210, discharge stations 216, or other stations or combinations of secondary processing stations 112. In FIG. 2 , the secondary circuit is shown as having a circular arrangement of secondary processing stations 112; however, as previously mentioned, the secondary circuit may position the secondary processing stations 112 in other geometric arrangements, such as linear, polygonal, or other arrangements. In one or more embodiments, the secondary processing stations 112 of the secondary circuit 118 may be used to form one or more features of a glass article 103, such as a vial, an ampoule, a cartridge, or a syringe, for example, on an end of the glass article 103 opposite the end formed by the main turret 108. For example, in some embodiments, the glass article 103 is a vial, and the forming station 204 of the secondary circuit 118 may form the bottom of the vial. Other features are also contemplated, such as features characteristic of an ampoule, a cartridge, a syringe, or the like. The secondary circuit 118 may include one or more polishing stations 208, where the surface of the glass article is finished. The secondary circuit 118 may further include multiple cooling stations 210 and a discharge station 216, where the finished glass article 103 may be discharged from the converter 100.

[0060] The foregoing description of the processing stations 106 of the main circuit 116 and the secondary processing stations 112 of the secondary circuit 118 may represent an exemplary converter 100 for producing vials from glass tubing 102. However, it should be understood that more or fewer processing stations 106 and secondary processing stations 112 may be utilized to produce vials having different shapes, or other glass articles, such as cartridges, syringes, ampoules, or other glass articles. Additionally, it should be understood that the processing stations 106 and secondary processing stations 112 may be arranged in any number of different orders and / or configurations to produce glass articles of different shapes.

[0061] Referring now to FIG. 3A, the heating stations 202 of the converter 100 are shown schematically. Each of the heating stations 202 may include one or more heating elements 301. As shown in FIG. 3A, in an embodiment, the heating elements 301 may include one or more burners 302 that can be used to heat a target area of ​​the glass tube 102 prior to a forming operation performed at the forming station 204 (FIG. 2) or a separating operation performed at the separating station 206 (FIG. 2). While FIG. 3A shows a single burner 302, it should be understood that multiple burners 302 may be used in a single heating station 202. Each burner 302 may be fluidly connected to a fuel supply 304, an oxygen supply 306, and, optionally, an air supply 308. Examples of fuels for the burners 302 may include, but are not limited to, hydrogen, hydrocarbon fuel gases (e.g., methane, propane, butane, etc.), other fuels, or combinations thereof. Each burner 302 may include a fuel control valve 310 to control the flow rate of fuel gas to the burner 302. Each burner 302 may also include an oxygen control valve 312 to control the mass flow rate of oxygen to the burner 302. Each burner 302 may further include an air control valve 314 to optionally control the flow rate of air to the burner 302. The burners 302 combust the fuel gas in the presence of oxygen and / or air to generate a flame and heat at least a target area of ​​the glass tube 102. Although the heating station 202 of the converter 100 is described herein as using a burner to heat the glass tube 102, it should be understood that other heating elements or methods other than a burner may be used to heat the glass tube 102.

[0062] 3B and 3C, exemplary forming stations 204 of the converter 100 are schematically illustrated. Each forming station 204 may include one or more forming tools 324 rotatable about a tool axis E relative to the base 104 (FIG. 1). Upon indexing to a forming station 204, the glass tube 102, heated in the previous heating station 202, is rotated by the holder 130. The forming tools 324 may engage the outer surface 140 of the glass tube 102 as it rotates. Contact between the forming tools 324 and the outer surface 140 of the heated glass tube 102 may form the glass tube 102 into a desired shape. Once the contact time expires, a forming tool actuator 326 disengages the forming tool 324 from engagement with the glass tube 102. FIG. 3B schematically illustrates one embodiment of a forming station 204 for forming a shoulder 142 of a glass vial formed from the glass tube 102. 3C schematically illustrates an exemplary embodiment of a forming station 204′ for forming the flange 144 of a glass vial formed from the glass tube 102. The forming station 204′ for forming the flange 144 includes three forming tools 324a, 324b, and 324c.

[0063] 3D schematically illustrates the cooling station 210 having one or more cooling nozzles 340 positioned to direct a cooling fluid 342, such as cooling air or an inert gas, toward the glass tube 102. One or more of the cooling nozzles 340 can be positioned to direct the cooling fluid 342 to specific regions of the glass tube 102. One or more cooling fluid control valves 344 can be fluidly connected to the cooling nozzles 340 to control the mass flow rate of the cooling fluid 342 to the cooling nozzles 340, thereby enabling control of the cooling rate of the glass tube 102, the temperature of the glass tube 102, and the temperature gradient within the glass tube 102.

[0064] Referring now to FIG. 3E, the separation station 206 of the converter 100 is shown schematically. The separation station 206 shown in FIG. 3E is a thermal separation station positioned after one or more heating stations 202 in the indexing direction 222 of the main turret 108. The heating station 202 positioned before the separation station 206 heats the glass tube 102 to make the glass viscous. The separation station 206 may include a separation burner 348. While the glass tube 102, rendered viscous by the previous heating station 202, is rotated by the holder 130 about the holder axis D, the separation burner 348 can engage the outer surface 140 of the glass tube 102, heating the glass tube 102 to a temperature at which the viscosity of the glass causes the article to separate from the glass tube 102. Once separated from the glass tube 102, the article can be transferred to the secondary turret 114 (FIG. 1) or ejected from the converter 100. Although shown as a thermal separation station in FIG. 3E, separation station 206 may also be a non-thermal separation station, such as a separation station that uses score-and-break techniques, such as may be used for syringes and cartridges.

[0065] 3F, a typical perforation station 212 of the converter 100 is shown schematically. The perforation station 212 is positioned after the separation station 206 in the index direction 222 of the main turret 108. As previously described, thermal separation of the article 103 from the glass tube 102 at the separation station 206 can result in the formation of a glass meniscus 350 across the working end 150 of the glass tube 102. At the perforation station, the meniscus 350 is perforated in preparation for forming the next article at the working end 150 of the glass tube 102. The perforation station 212 can include a perforation burner 352. The perforation burner 352 can be positioned below the working end 150 of the glass tube 102 and can be oriented toward the working end 150 of the glass tube 102. The perforation burner 352 can be fluidly connected to one or more, or combinations of, the fuel gas supply 304, the oxygen supply 306, and the air supply 308. The fuel gas supply 304, the oxygen supply 306, and the air supply 308 were previously described in connection with the burner 302 of FIG. 3A. When the main turret 108 indexes the glass tube 102 to the perforation station 212, the flame from the perforation burner 352 heats the glass meniscus 350, melting it so that the glass meniscus 350 is perforated and reopening the working end 150 of the glass tube 102.

[0066] 3A-3F include schematic diagrams of several different example processing stations 106 that may be utilized in converter 100. However, it should be understood that other processing stations 106 having different structures, combinations of structures, or functionality may be utilized to achieve the desired conversion of glass tube 102 into one or more glass articles.

[0067] 1 and 2, during operation, the main turret 108 indexes the glass tube 102 secured in the holder 130 to the processing stations 106. A specific operation, such as heating, forming, piercing, separating, cooling, dropping, or feeding, is performed on the glass tube 102 at each of the processing stations 106. As used herein, the "dwell time" of the converter 100 refers to the time the glass tube 102 spends at a particular processing station 106 before being indexed by the main turret 108 to the next subsequent processing station 106. The converter 100 can adjust the time so that all processing stations 106 complete their operations within the dwell time. At the end of the dwell time, the main turret 108 indexes the glass tube 102 to the next processing station 106. As used herein, the "index time" refers to the time, measured in hours, it takes the main turret 108 to index the glass tube 102 from one processing station 106 to the next. As used in this disclosure, the total time per station per part is the sum of the dwell time and the index time.

[0068] An example of a converter 100 for converting glass tubes 102 into glass vials is the vial forming machine model RP16 with automatic tube feeder manufactured by AMBEG Dr. J. Dichter GmbH, which includes 16 processing stations 106 in the main circuit 116 and eight secondary processing stations 112. Other examples include the vial forming machine model RP32 manufactured by AMBEG Dr. J. Dichter GmbH, which includes 32 processing stations 106 in the main circuit 116 and two secondary circuits 118 with eight secondary processing stations 112 in each secondary circuit 118, and the Zeta098 vial forming machine manufactured by Euromatic SRL, which includes 36 processing stations. Another example includes the Zeta103 cartridge forming machine manufactured by Euromatic SRL, which is a glass tube to cartridge converter. Cartridge converters have similar features to the previously described vial converter 100, but are utilized to produce glass articles having a cartridge form factor rather than a vial.

[0069] Although described in the context of converter 100 for producing glass vials from glass tubes 102, it should be understood that converter 100 may be configured to produce one or more other articles, such as cartridges, syringes, ampoules, or other glass articles, by modifying forming tools 324 and / or by changing the order or configuration of processing stations 106 in main circuit 116 or secondary processing stations 112 in one or more secondary circuits 118.

[0070] Referring again to FIGS. 1 and 2 , during the conversion process, the glass tube 102 is loaded into the converter 100 at room temperature (approximately 23° C.), but the temperature can rise to 200° C. or higher during consumption of the glass tube 102. Variations in the temperature of the glass tube 102 during consumption are at least partially due to heat generated by the burner 302 and other heat sources provided to the converter 100. The temperature can also change due to changes in the gas flow rate through the glass tube 102 as the length of the glass tube 102 decreases. As previously mentioned, the temperature of the glass tube 102 changes during processing and consumption of the glass tube 102, which can cause dimensional and appearance variations in the glass article formed during the conversion process. Variations in glass tube temperature and the resulting dimensional and appearance variations can constrain the operating window of the conversion process, reduce process capability (Cpk), and reduce yield.

[0071] The systems and methods of the present disclosure relate to reducing the temperature variation of the glass tube 102 and the resulting dimensional and appearance variation of the article produced from the glass tube 102 by increasing or decreasing the amount of heat at the working end 150 of the glass tube 102 based on the article number corresponding to the working end 150 of the glass tube 102. Referring to Figure 4, a length of the glass tube 102 before conversion is shown schematically. The glass tube 102 has a starting length L T , an outer diameter OD, an inner diameter ID, and a glass thickness T. The glass tube 102 can be sectioned or conceptually divided into a plurality of continuous segments 146, each of which has a length L sufficient to form an article from the continuous segment 146. SEach of the plurality of consecutive segments 146 may correspond to an article and may be associated with an article number. The article number may be an integer from 1 to n, with 1 corresponding to the first article made from the glass tube 102 and n corresponding to the last article made from the glass tube 102 and the total number of articles that can be made from the glass tube 102. An article number may be assigned to each successive article made from the glass tube, from article number 1 to article number n. Each time the glass tube 102 passes through a circuit of processing stations 106 in the converter 100, a glass article is made and the article number at the working end 150 of the glass tube 102 is incremented by one. After article n is formed, the glass tube 102 is consumed, and another glass tube 102 can be loaded into the holder 130.

[0072] As previously mentioned, the temperature of the glass tube 102 may vary as the glass tube 102 is gradually consumed with each rotation of the main turret 108 of the converter 100. Thus, the temperature of the glass tube 102 may be a function of the article number at the working end 150 of the glass tube 102. This temperature variation may cause the heated glass in the glass tube 102 to vary in viscosity during heating and forming, which may result in dimensional and appearance variations. The dimensional variation of the glass article made from the glass tube 102 is directly proportional to the temperature variation of the glass tube 102.

[0073] Referring to FIG. 5, a graph shows a parameter indicating the dimensions (y-axis) of articles produced from a glass tube 102 as a function of article number (x-axis). As shown in FIG. 5, the dimensions of the finished articles can change rapidly over the first 10-15 articles produced from a newly loaded glass tube. At least part of this dramatic change in the dimensions of the finished articles over the first 10-15 articles can be attributed to the changing glass tube temperature during this time. Dimensional variability can decrease with larger article numbers. However, dimensional variability of the first few articles produced from a glass tube can cause these articles to be out of specification. Rejection of these articles due to out-of-specification can reduce the yield of glass articles from the glass tube.

[0074] As previously described, the systems and methods of the present disclosure relate to reducing temperature variations in a glass tube 102 during consumption of the glass tube 102 at the converter 100 by adjusting heating of the glass tube 102 in one or more heating stations 202 of the converter 100 based on the item number at the working end 150 of the glass tube 102. Heating of the glass tube 102 can be adjusted by changing the burner residence time of a burner 302 engaging the glass tube 102 at one or more heating stations 202, changing the heating rate of a burner 302 in one or more heating stations 202, changing the exhaust flow rate proximate one or more heating stations 202, or a combination thereof. Heating of the glass tube 102 can be adjusted per item and / or per rotation (e.g., with each rotation of the main turret 108 of the converter 100) based on the item number. For each item, the amount of heating is adjusted based on the item number each time the main turret 108 of the converter 100 indexes. For each revolution, the amount of heating is adjusted once at the beginning of each revolution of the main turret 108, and the amount of heating is maintained throughout the revolution.

[0075] Referring to FIG. 6 , a heating station 202 of a converter 100 is shown schematically in accordance with one embodiment of the present disclosure. A system of the present disclosure for producing multiple articles from a glass tube 102 may include the converter 100. The converter 100 may include multiple processing stations 106, including at least one heating station 202, at least one forming station 204, and a separation station 206. The converter 100 may be operable to index the glass tube 102 through the multiple processing stations 106. The converter 100 may have any of the other features or characteristics described herein above for the converter 100. The system may further include a system controller 400 communicatively connected to the converter 100, which may include a processor 402 and a storage medium 404 containing computer-readable and executable instructions 406. The system controller 400 may be operable to track an item number at the working end 150 of the glass tube 102 and to adjust heating of the glass tube 102 within the heating station 202 based on the item number at the working end 150 of the glass tube 102. When executed by the processor 402, the computer-readable and executable instructions 406 may cause the system controller 400 to automatically track the item number at the working end 150 of the glass tube 102. As described above with respect to FIG. 4 , the item number may be an integer corresponding to consecutive segments 146 of the initial length of the glass tube 102, with each consecutive segment corresponding to an item. When executed by the processor 402, the machine-readable and executable instructions 406 may further cause the system controller 400 to increase or decrease the amount of heating of the working end 150 of the glass tube 102 based on the item number at the working end 150 of the glass tube 102. Heating of the working end 150 of the glass tube 102 can be increased or decreased by changing the burner residence time at one or more heating stations 202, changing the heating rate of the burner 302 within one or more heating stations 202, changing the exhaust flow rate adjacent to one or more heating stations 202, or a combination thereof.The heating of the glass tube 102 can be increased or decreased in a single heating station 202 or in multiple heating stations 202 .

[0076] Referring again to FIG. 6 , heating of the glass tube 102 can be increased by increasing the burner residence time in the heating station 202, or decreased by decreasing the burner residence time. As previously described, burner residence time refers to the duration of time that the flame of the burner 302 engages the glass tube 102 and the glass tube 102 is heated. Increasing or decreasing the amount of heating of the working end 150 of the glass tube 102 may include increasing or decreasing the burner residence time of the glass tube 102 engaged with the burner 302 in at least one heating station 202 based on the item number at the working end 150 of the glass tube 102. The burner residence time can be increased or decreased in one or more heating stations 202 based on the item number at the working end 150 of the glass tube 102.

[0077] The burner residence time can be increased or decreased by adjusting the timing of the burner 302 moving into or out of engagement with the glass tube 102. Engagement of the burner 302 with the glass tube 102 can refer to positioning the burner 302 in a position where the flame from the burner 302 extends toward the glass tube 102, or in a position where the flame from the burner 302 contacts and heats the glass tube 102. Conversely, when the burner 302 is not engaged with the glass tube 102, the burner 302 is positioned in a position where the flame from the burner 302 is directed away from the glass tube 102, so that the flame does not contact or directly heat the glass tube 102. Some heat transfer from the burner 302 to the glass tube 102 may occur even when the burner 302 is not engaged with the glass tube 102, but this heating is incidental and minimal compared to the heating of the glass tube 102 when the burner 302 is engaged with the glass tube 102.

[0078] 7A and 7B, in an embodiment, the burner 302 in the heating station 202 may be a swirl burner 330 operable to pivot laterally about an axis F (e.g., in an XY plane according to the coordinate axes of FIG. 6) to engage or disengage the glass tube 102. The swirl burner 330 may include a swirl burner actuator 332 operably coupled to the swirl burner 330. The swirl burner actuator 332 may pivot the swirl burner 330 about the axis F, such that the flame of the swirl burner 330 is moved into and out of engagement with the glass tube 102. The swirl burner actuator 332 may be communicatively connected to the system controller 400, such as in electrical communication with the system controller 400. The swirl burner actuator 332 may be operable to receive a control signal from the system controller 400, which can cause the swirl burner actuator 332 to swirl the swirl burner 330 to engage or disengage from the glass tube 102.

[0079] The swirl burner 300 can swirl to engage or disengage the working end 150 of the glass tube 102. Referring to FIG. 7A, the swirl burner 330 is illustrated in a position where the flame of the swirl burner 330 engages the glass tube 102, heating the glass tube 102. In the engaged position, the flame of the swirl burner 330 can contact the glass tube 102 or point toward the glass tube 102. In an embodiment, in the engaged position, the swirl burner 330 and flame can be aligned along a line G extending through the axis of rotation D of the glass tube 102. FIG. 7B shows the swirl burner 330 in a position where the flame of the swirl burner 330 does not engage the glass tube 102. In the disengaged position, the flame of the swirl burner 330 points away from the glass tube 102, such that the flame does not contact or point directly at the glass tube 102. In an embodiment, when disengaged, the swirl burner 330 may be oriented such that the swirl burner 330 is not aligned with a line G that intersects the rotation axis D of the glass tube 102.

[0080] In embodiments, the swirl burner actuator 332 may be operable to transition the swirl burner 330 between a position in which it engages the glass tube 102 and a position in which it does not engage the glass tube 102. In other words, the swirl burner actuator 332 may swirl the swirl burner 330 into and out of engagement with the glass tube 102. In embodiments, the swirl burner 330 may normally be in a position in which it engages the glass tube 102, and the swirl burner actuator 332 may be operable to swirl the swirl burner 330 out of engagement with the glass tube 102. Alternatively, the swirl burner 330 may not normally engage the glass tube 102, and the swirl burner actuator 332 may be operable to swirl the swirl burner 330 into engagement with the glass tube 102.

[0081] 7A, during operation of the system, the glass tube 102 may be indexed to the heating station 202. The glass tube 102 may be a new glass tube with an item number of 1 at the working end 150, or may be a partially consumed glass tube with an item number greater than 1. The swirl burner 330 may transition to a position engaging the glass tube 102 at time T1. In an embodiment, time T1 may be equal to the time at which the converter 100 ends its indexing, which is the time at which the glass tube 102 is fully indexed to the heating station 202. For example, the swirl burner 330 may transition to the engaging position of FIG. 7A during the indexing of the converter 100 or at the same time that the glass tube 102 is fully indexed to the heating station 202 (e.g., upon reaching a resting position within the heating station 202), such that the flame of the swirl burner 330 contacts and heats the glass tube 102 as soon as the glass tube 102 reaches a resting position within the heating station 202. Alternatively, in an embodiment, time T 1 may occur after the glass tube 102 is fully indexed into the heating station 202 .

[0082] The swirl burner 330 may maintain engagement with the glass tube 102 for the duration of the burner residence time (the duration between time T1 and time T2). At the end of the burner residence time, time T2, the swirl burner 330 may be swung out of engagement with the glass tube 102, as shown in FIG. 7B, and heating of the glass tube 102 is stopped. As previously described, a target burner residence time for the glass tube 102 may be determined based on the item number at the working end 150 of the glass tube 102. The burner residence time of the glass tube 102 in the heating station 202 may be adjusted by changing the timing at which the swirl burner 330 swirls into and out of engagement with the working end 150 of the glass tube 102. Time T1, time T2, or both may be adjusted to increase or decrease the burner residence time based on the item number at the working end 150 of the glass tube 102.

[0083] The burner residence time can be adjusted based on the item number at the working end 150 of the glass tube 102 after each index of the main turret 108 of the converter 100. In other words, the burner residence time can be adjusted based on the item number of each successive glass tube 102 indexed to the heating station 202. Thus, the item number at the working end 150 of each glass tube 102 can be individually tracked, allowing the burner residence time to be adjusted for each glass tube 102 independently of all other glass tubes 102. Adjusting the burner residence time based on the item number of the glass tube 102 with each index of the converter 100 can allow for random replacement of a new glass tube 102 each time a glass tube 102 is completely consumed, eliminating the need to load new glass tubes 102 in sequential order.

[0084] In embodiments, the burner residence time can be adjusted with each rotation of the main turret 108 of the converter 100 based on the item numbers at the working ends 150 of the glass tubes 102. In these embodiments, as each glass tube 102 is consumed, it can be replaced with a new length of glass tube 102 in direct succession (immediately after the others), such that new lengths of glass tube 102 are loaded into all holders 130 in the main turret 108 during the same rotation of the main turret 108. As new glass tubes 102 are loaded in sequence, the item numbers at the working ends 150 of the glass tubes 102 should be the same for all glass tubes 102 indexed through the heating station 202 during a single rotation. Thus, in these embodiments, the burner residence time can be increased or decreased once per rotation of the converter 100 based on the item numbers at the working ends 150 of all glass tubes 102. New lengths of glass tube 102 can be secured to each glass tube holder in consecutive order, starting with the first glass tube. In response to a change in the item number at the working end 150 of the first glass tube 102 at at least one heating station 202, the burner dwell time at the working end 150 of the first glass tube 102 can be adjusted based on the item number, and the burner dwell time can be maintained at the heating station 202 from glass tube 102 to glass tube 102 until the first glass tube returns to the heating station 202 and the item number at the working end 150 of the first glass tube changes.

[0085] 7A and 7B, the system may include computer-readable and executable instructions 406 that, when executed by the processor 402, cause the system controller 400 to determine an item number corresponding to the working end 150 of the glass tube 102 and automatically increase or decrease the burner residence time at the working end 150 of the glass tube 102 based on the item number at the working end 150 of the glass tube 102 by pivoting the swirl burner 330 into or out of engagement with the working end 150 of the glass tube 102. The system controller 400 may send a first control signal to the swirl burner 330 or the swirl burner actuator 332 at time T1, causing the swirl burner 330 or the swirl burner actuator 332 to transition the swirl burner 330 into engagement with the glass tube 102. At the end of the burner residence time at time T2, the system controller 400 can send a second control signal to the swirl burner 330 or the swirl burner actuator 332 commanding the swirl burner 330 to move to a position where it does not engage the glass tube 102.

[0086] 7A and 7B are shown as including a swirl burner 330 that swirls about an axis F to move the flame into and out of engagement with the glass tube 102, it should be understood that other mechanisms for moving the burner 302 into and out of engagement with the glass tube 102 are contemplated. In embodiments, the heating station 202 may include a translation system operable to translate the burner 302 in a linear direction to move it into and out of engagement with the glass tube 102. For example, the translation system may include a track and a burner support that engages with the track and is translatable along the track to move the burner 302 into and out of engagement with the glass tube 102. The translation system may also include one or more linear actuators, such as a piston, that can transition the burner 302 into and out of engagement with the glass tube 102.

[0087] The heating station 202 is described herein in the context of a burner 302 used to heat the glass tube 102. However, it should be understood that other heating elements may be used to heat the glass tube. Other heating elements include, but are not limited to, lasers, such as CO lasers, induction heaters, other heating devices, or combinations thereof. The laser heating element can be turned off and on to engage or disengage the heating element from the glass tube 102.

[0088] Referring now to FIG. 8 , a graph illustrates the effect of adjusting the burner residence time based on the item number at the working end 150 of the glass tube 102 on the variability of glass article dimensions produced from the glass tube 102. FIG. 8 illustrates a parameter that indicates a specific dimension of a glass article (y-axis) as a function of the item number (x-axis). Line 502 corresponds to a converter operating without supplemental heating of the glass tube 102. Line 502 illustrates the average dimension of glass articles for each item number, which is the average of all 16 articles with the same item number produced during one revolution of a converter having 16 processing stations in the main turret. As shown in FIG. 8 , when supplemental heating of the glass tube 102 is not provided, the article dimensions can vary significantly from the first article to the nth article (the 29th article). In particular, the dimensions of the glass tube 102 change rapidly over the first few articles as the temperature of the glass tube 102 increases. The dimensions plateau for a few more items before changing rapidly again above item number 12 as the gas flow rate through the glass tube 102 increases due to the overall length of the glass tube 102 decreasing.

[0089] Line 504 in FIG. 8 corresponds to data generated by a converter operating with supplemental heating of a fixed duration at one heating station 202, provided by a swirl burner with a fixed residence time. As shown by line 504, providing supplemental heating of a fixed duration can result in a deviation in glass article dimensions compared to operating the converter 100 without supplemental heating. While not intending to be bound by any particular theory, this is believed to be due to an increase in the overall temperature of the glass tube 102 at the working end 150, which can reduce the viscosity of the glass and cause a dimensional deviation. This dimensional deviation using supplemental heating of a fixed residence time can result in an out-of-specification article. However, this illustrates that varying the amount of heating at the heating station 202 can change the dimensions of the article produced from the glass tube 102.

[0090] Line 506 in FIG. 8 corresponds to the operation of a converter 100 in which a swirl burner 330 is installed in a processing station 106 that previously did not have a burner, and the burner residence time is adjusted based on the item number at the working end 150 of each glass tube 102 indexed to the processing station 106. In line 506, the burner residence time is adjusted each time the converter 100 is indexed (e.g., for each item). As shown by line 506, adjusting the burner residence time based on the item number at the working end 150 of the glass tube 102 reduces dimensional variation. Additionally, adjusting the burner residence time based on the item number at the working end 150 of the glass tube 102 does not result in dimensional deviation compared to the target dimension. Similar results can be shown by replacing the fixed burner at the heating station 202 with a swirl burner 330 and modifying the burner residence time. The variability in the dimensions of line 506 can be further reduced by further enhancing and refining the models, algorithms, and programs used to control the adjustment of residence time.

[0091] In embodiments, by adjusting the heating of the glass tube 102 based on the item number at the working end 150 of the glass tube 102, the variability in the location or dimension of features of the article produced from the glass tube 102 can be reduced to less than 0.5 mm, less than 0.4 mm, less than 0.3 mm, or even less than 0.2 mm compared to a conversion process that does not adjust the amount of heating based on the item number. In embodiments, by adjusting the heating of the glass tube 102 based on the item number at the working end 150 of the glass tube 102, the variability in the location or dimension of features of the article produced from the glass tube 102 can be reduced by at least 50%, at least 60%, at least 70%, or even at least 80% compared to a conversion process that does not adjust the amount of heating based on the item number.

[0092] Referring again to FIG. 6 , the amount of heating of the glass tube 102 in the heating station 202 can be increased by increasing the heating rate in the heating station 202 or decreased by decreasing the heating rate, depending on the item number at the working end 150 of the glass tube 102. The heating rate in the heating station 202 can refer to the amount of thermal energy output per unit time of the heating element in the heating station 202. The heating element in the heating station 202 can be the burner 302 as described above. The heating rate of the burner 302 can be adjusted by changing the amount (flow rate) of one or more combustion gases introduced into the burner 302. As used herein, the term “combustion gas” refers to gases, such as fuel gas, oxygen, and / or air, delivered to the burner 302 as a source of combustion reactants, which are combusted to generate heat for heating the glass tube 102. The term “combustion gas” is not intended to refer to a gas stream containing combustion reaction products produced by combustion. The combustion gas can include fuel gas, oxygen gas, air, or a combination thereof. The heating rate of a heating element such as a burner 302 can be adjusted at one or more heating stations 202 provided in the converter based on the item number at the working end 150 of the glass tube 102 to compensate for variability in the temperature of the glass tube 102 throughout the conversion process.

[0093] As previously described herein, the heating station 202 may include one or more burners 302. Each burner 302 may be fluidly connected to a fuel supply 304, an oxygen supply 306, and optionally an air supply 308. Each burner 302 may include at least one operable fluid control valve to control the flow, such as the mass flow, of one or more combustion gases to the burner 302. For example, each burner 302 may be fluidly connected to a fuel control valve 310 for controlling the flow of fuel gas to the burner 302, an oxygen control valve 312 for controlling the mass flow of oxygen to the burner 302, and optionally an air control valve 314 for optionally controlling the flow of air to the burner 302. The burner 302 combusts the fuel gas in the presence of oxygen and / or air to generate a flame that heats at least a target region of the glass tube 102. The fuel control valve 310, the oxygen control valve 312, and optionally the air control valve 314 may each be communicatively connected to the system controller 400, such as by electronically communicating with the system controller 400. The fuel control valve 310, the oxygen control valve 312, and optionally the air control valve 314 may each be operable to receive signals from the system controller 400 that direct the flow rates of the fuel gas, oxygen, and air to supply to the burner 302. The flow rate of each gas may be a mass flow rate, and the fuel control valve 310, the oxygen control valve 312, and optionally the air control valve 314 may be mass flow controllers. In an embodiment, the fuel control valve 310, the oxygen control valve 312, and optionally the air control valve 314 may not be communicatively connected to the system controller 400, but may be set to provide a constant fuel-to-oxygen ratio. In these embodiments, the system may include a main combustion gas flow controller fluidly connected to the burner 302 and communicatively connected to the system controller 400. The main combustion gas flow controller may be operable to control the total mass flow of combustion gases to the burner 302, the combustion gases having a constant fuel gas to oxygen ratio set by the fuel control valve 310, the oxygen control valve 312, and optionally the air control valve 314.Other configurations of various control valves for the combustion gases are contemplated to control the heating rate of the burners 302 within the heating station 202 .

[0094] The heating rate of each burner 302 can be increased or decreased by increasing or decreasing a flow rate, such as the mass flow rate of one or more of fuel gas, oxygen gas, air, or a combination thereof, to the burner 302. Increasing or decreasing the heating rate of a burner 302 in the heating station 202 may include proportionally increasing or decreasing the flow rate of all combustion gases. In other words, the fuel gas-to-oxygen ratio of the combustion gases introduced to the burner 302 can be maintained constant, and the total flow rate of the combustion gases can be increased to increase the heating rate of the burner 302, or the total flow rate of the combustion gases can be decreased to decrease the heating rate of the burner 302. In an embodiment, the fuel control valve 310, the oxygen control valve 312, and optionally the air control valve 314 can be operated to increase or decrease the mass flow rate of all combustion gases to the burner 302 while maintaining the fuel gas-to-oxygen ratio constant. In an embodiment, increasing or decreasing the heating rate of the glass tube 102 based on the item number at the working end 150 of the glass tube 102 may include modifying the mass flow ratio of fuel gas to oxygen supplied to the burner 302.

[0095] 6, the system may include computer-readable and executable instructions 406 that, when executed by the processor 402, cause the system controller 400 to determine an item number at the working end 150 of the glass tube 102 and automatically increase or decrease the mass flow rate of one or more combustion gases to at least one burner 302 in the heating station 202 based on the item number at the working end 150 of the glass tube 102. When executed by the processor 402, the computer-readable and executable instructions 406 may cause the system controller 400 to send control signals to one or more of the fuel gas control valve 310, the oxygen control valve 312, the air control valve 314, or a combination thereof, the control signals indicating the position of each flow control valve to achieve a desired heating rate of the burner 302. In an embodiment, when executed by the processor 402, the computer readable and executable instructions 406 can cause the system controller 400 to send control signals to the fuel gas control valve 310, the oxygen control valve 312, and optionally the air control valve 314 to increase or decrease the flow rates of fuel gas, oxygen, and optionally air to the burner 302 while maintaining a constant fuel gas to oxygen mass flow ratio introduced to the burner 302.

[0096] Referring now to FIG. 9 , the temperature (y-axis) of the glass tube 102 in the heating station 202 as a function of time (x-axis) is illustrated for a constant combustion gas flow rate (reference numeral 902) and an increase in combustion fuel gas flow rate at time equal to zero (reference numeral 904). Time equal to zero represents the end of the index time of the transducer 100 and the point at which the glass tube 102 reaches a rest position in the heating station 202. Under a constant combustion gas flow rate, the temperature of the glass tube 102 may increase with an increase in residence time in the heating station 202, as shown by line 902. In line 904, the flow rate of combustion gas to the burner 302 in the heating station 202 gradually increases with time equal to zero. As shown in FIG. 9 , there is a delay in the response of the temperature of the glass tube 102 to changes in the flow rate of combustion gas to the burner 302. Initially, when the combustion gas flow rate is changed at time equal to zero, the temperature (904) of the glass tube 102 continues to rise at the same rate as the temperature (902) of the glass tube 102 with a constant combustion gas flow. At a residence time of approximately 0.5 seconds, the effect of changing the combustion gas flow rate begins to be felt, and the heating rate of the burner 302 increases, as shown by the deviation of line 904 from line 902, which begins approximately 0.5 seconds after time equals zero. The heating rate of the burner 302 takes time to increase to its final heating rate after the change in combustion gas flow rate. This is shown in FIG. 9 by the period between 0.5 seconds and approximately 0.8 seconds, during which the slope of the temperature change is greater than the slope of the temperature change after 0.8 seconds. This indicates a delayed response of the heating rate of the burner 302 to the change in combustion gas flow rate.

[0097] The heating rate of the heating element / burner 302 in the heating station 202 can be adjusted based on the item number at the working end 150 of the glass tube 102 after each index of the main turret 108 of the converter 100. In other words, the heating rate of the burner 302 can be adjusted based on the item number of each successive glass tube 102 indexed to the heating station 202. Thus, the item number at the working end 150 of each glass tube 102 can be individually tracked, allowing the heating rate of the heating element to be adjusted for each glass tube 102 item, independent of all other glass tubes 102. Adjusting the heating rate based on the glass tube 102 item number with each index of the converter 100 can allow for random loading of a new glass tube 102 each time a glass tube 102 is completely consumed, eliminating the need to load new glass tubes 102 in sequential order. However, as shown in FIG. 9, the delayed response of the temperature of the glass tube 102 to changes in the flow rate of combustion gas to the burner 302 can limit the ability of changes in heating rate to adequately compensate for changes in the temperature of the glass tube 102 on a per-index basis.

[0098] In embodiments, the heating rate of the heating element or burner 302 can be adjusted with each rotation of the main turret 108 of the converter 100 based on the item numbers at the working ends 150 of the glass tubes 102. In these embodiments, as they are consumed, each glass tube 102 can be replaced with a new length of glass tube 102 in direct succession (immediately after the others), such that new lengths of glass tube 102 are loaded into all holders 130 of the main turret 108 during the same rotation of the main turret 108. Under these circumstances, the item numbers at the working ends 150 of the glass tubes 102 can be the same for all glass tubes 102 indexed through the heating station 202 during a single rotation. Thus, in these embodiments, the heating rate can be increased or decreased based on the item numbers at the working ends 150 of all glass tubes 102 once per rotation of the converter 100. New lengths of glass tube 102 can be secured to each holder 130 in consecutive order, starting with the first glass tube. In response to a change in the item number at the working end 150 of the first glass tube 102 at at least one heating station 202, the heating rate of the burner 302 can be adjusted based on the item number at the working end 150 of the glass tube 102, and the heating rate of the burner 302 can be maintained from glass tube 102 to glass tube 102 at the heating station 202 until the first glass tube returns to the heating station 202 and the item number at the working end 150 of the first glass tube changes. Varying the heating rate of the burner 302 from one rotation to the next can reduce the impact of a delay in the thermal response of the burner 302 to changes in the flow rate of the combustion gases.

[0099] 10A, there is shown a schematic diagram of article dimensions (y-axis) from a glass tube 102 as a function of article number (x-axis) at the working end 150 of the glass tube 102 for a converter with no compensation for variability in the temperature of the glass tube 102. As shown in FIG. 10A, the average dimensions of the articles vary dramatically over the first 10-15 articles produced from the glass tube (the first 10-15 revolutions of the main turret). This variability can result in articles initially produced from the glass tube being out of specification, which can reduce yield and increase waste from the conversion process.

[0100] 10B, a graph of article size (y-axis) produced from a glass tube 102 as a function of the article number (x-axis) at the working end 150 of the glass tube 102 is shown for a converter in which the heating rate of the burner 302 in the heating station 202 is adjusted on a rotation-by-rotation basis based on the article number at the working end 150 of the glass tube 102. As shown in FIG. 10B, adjusting the heating rate of the burner 302 in the heating station 202 on a rotation-by-rotation basis based on the article number at the working end 150 of the glass tube 102 can significantly reduce the variability in the size of the articles produced from the glass tube, particularly over the first 10-15 articles produced from each glass tube 102. Adjusting the burner heating rate on a rotation-by-rotation basis based on the article number can reduce the variability in article size by at least 50%, at least 60%, at least 70%, or even at least 80% compared to a converter in which the burner heating rate is maintained constant. Therefore, by varying the heating rate of one or more burners 302 in one or more heating stations 202 based on the item number at the working end 150 of the glass tube 102, variability in the dimensions and appearance of the finished item can be reduced.

[0101] 11 , heating of the glass tube 102 at the heating station 202 can also be adjusted based on the item number at the working end 150 of the glass tube 102 by varying the flow rate of exhaust air proximate the heating station 202. The converter 100 can include an exhaust system 670 that can include one or more inlet vents 672 fluidly connected to an air handler 674 by a duct 676. The air handler 674 can be capable of drawing air into the inlet vents 672 and through the duct 676. Drawing air into the exhaust system through the inlet vents 672 can create a localized negative pressure in the region of the working end 150 of the glass tube 102, which can sufficiently reduce or overcome the chimney effect within the glass tube 102, reducing or preventing at least the upward flow of gases through the center of the glass tube 102. Reducing or preventing the flow of gases upward through the glass tube 102 can reduce the impact of these gases on the temperature variability of the glass tube 102. Additionally or alternatively, by varying the negative pressure near the working end 150 of the glass tube 102, the flow rate of gas through the interior volume of the glass tube 102 can be adjusted, thereby controlling the transfer of heat to the unmachined length of the glass tube 102. The local negative pressure created by the exhaust system 670 can also remove excess heat from outside the glass tube 102, such as from the air surrounding the exterior of the glass tube 102.

[0102] The inlet vent 672 can be positioned at the working end 150 of the glass tube 102 a distance M from the outer surface 140 of the glass tube 102. The distance M can be small enough to allow the exhaust system 670 to generate a negative pressure at the working end 150 of the glass tube 102 sufficient to at least partially or completely overcome the chimney effect in the interior volume of the glass tube 102. However, if the distance M is too small, the inlet vent 672 may contact the working end 150 of the glass tube 102 due to slight dimensional variations in the glass tube 102 and / or the converter 100 as the glass tube 102 indexes in and out of the processing station 106. Additionally, if the distance M is too small, the inlet vent 672 may interfere with the performance of a burner, such as burner 302, in one of the heating stations 202.

[0103] The air handler 674 may include one or more of, but is not limited to, a blower, a fan, a pump, a vacuum pump, other vacuum or air handling equipment, or a combination thereof. In embodiments, the exhaust system 670 may include multiple air handlers 674, and one or more processing stations 106, such as the heating station 202 or the separation station 212, may have its own dedicated air handler. The duct 676 connecting the air handler 674 to the inlet vent 672 may include a rigid duct, a flexible duct, or a combination of both. A flexible duct may be provided so that the position of the inlet vent 672 automatically adjusts relative to the working end 150 of the glass tube 102. Due to the proximity of the inlet vent 672 and duct 676 to the processing stations 106, in some embodiments, the inlet vent 672 and duct 676 may be constructed of a heat-resistant material capable of withstanding the temperatures of the heated gases and vapors generated in the heating station 202 in proximity to the glass tube 102.

[0104] The exhaust system 670 may optionally include a damper 680 disposed within the duct 676, between the duct 676 and the air handler 674, or between the duct 676 and the inlet vent 672. The damper 680 is adjustable to control the airflow through the exhaust system 670, thereby controlling the negative pressure generated by the exhaust system 670 at the working end 150 of the glass tube 102. The damper 680 may include one or more of a pneumatic actuator, an electric actuator, a fluid pressure actuator, an electromagnetic actuator, or other types of actuators. In some embodiments, the damper 680 may include a solenoid. The air handler 674, the damper 680, or both, may be communicatively coupled to the system controller 400 and operable to receive control signals from the system controller 400 to control the airflow through the exhaust system 670.

[0105] Referring again to FIG. 11 , the inlet vent 672 can be positioned proximate the heating station 202. In embodiments, the exhaust system 670 can include multiple vents 672, with each vent 672 positioned in one of the processing stations 106, such as the heating station 202. During operation, the inlet vent 672 can be positioned proximate the working end 150 of the glass tube 102, as previously described. The air handler 674 can generate an airflow from the inlet vent 672 through the duct 676 toward the air handler 674. Air and gases from near the working end 150 of the glass tube 102 can be drawn into the inlet vent 672 by the air flow through the duct 676, thereby creating a negative pressure proximate the working end 150 of the glass tube 102. The negative pressure can reduce or overcome the chimney effect, reducing or preventing the flow of gases and vapors through the interior volume of the glass tube 102. The airflow through the exhaust system 670 can be adjusted by changing the speed of the air handler 674, changing the position of the damper 680, or both. The negative pressure created adjacent the working end 150 of the glass tube 102 can be modified by changing the speed of the air handler 674, changing the position of the damper 680, changing the position of the inlet vent 672 relative to the working end 150 of the glass tube 102, or a combination thereof. By changing the negative pressure, the flow rate of gas through the interior volume of the glass tube 102 can be adjusted.

[0106] As previously described, the heating of the glass tube 102 in the heating stations 202 can be adjusted by modifying the operation of the exhaust system 670 at the heating stations 202 based on the item number at the working end 150 of the glass tube 102. Increasing or decreasing the amount of heating of the glass tube 102 in one or more heating stations 202 may include adjusting the negative pressure generated by the exhaust system 670 proximate to the glass tube 102 based on the item number at the working end 150 of the glass tube 102. As previously described, adjusting the negative pressure generated by the exhaust system 670 proximate to the glass tube 102 may include adjusting the speed of the air handler 674, adjusting the position of the damper 680, adjusting the position of the inlet vent 672 relative to the glass tube 102, or a combination thereof. In an embodiment, increasing or decreasing the amount of heating of the glass tube 102 in the heating stations may include adjusting the exhaust flow rate proximate at least one heating station 202 based on the item number at the working end 150 of the glass tube 102. Adjusting the exhaust flow rate may include adjusting the speed of air handler 674, adjusting the position of damper 680, or both.

[0107] 11 , the system may include computer-readable and executable instructions 406 that, when executed by the processor 402, cause the system controller 400 to determine an item number at the working end 150 of the glass tube 102 and automatically adjust the negative pressure created by an exhaust system 670 proximate the glass tube 102 based on the item number at the working end 150 of the glass tube 102. In an embodiment, the exhaust system 670 may include an air handler 674 that may be communicatively connected to the system controller 400, and computer-readable and executable instructions 406 that, when executed by the processor 402, cause the system controller 400 to automatically adjust the speed of the air handler 674 based on the item number at the working end 150 of the glass tube 102. The computer readable and executable instructions 406, when executed by the processor 402, can cause the system controller 400 to send control signals to the air handler 674 instructing the adjusted speed of the air handler 674 depending on the item number of the working end 150 of the glass tube 102.

[0108] In an embodiment, the exhaust system 670 may include a damper 680 that may be communicatively coupled to the system controller 400, and the computer readable and executable instructions 406, when executed by the processor 402, may cause the system controller 400 to automatically adjust the position of the damper 680 based on the item number at the working end 150 of the glass tube 102. The computer readable and executable instructions 406, when executed by the processor 402, may cause the system controller 400 to send a control signal to the damper 680 indicating the position of the damper 680 as a function of the item number at the working end 150 of the glass tube 102.

[0109] In an embodiment, the exhaust system 670 may include a vent actuator operable to translate the inlet vent 672 relative to the glass tube 102, such as moving the inlet vent 672 toward or away from the glass tube 102. The vent actuator may be communicatively coupled to the system controller 400, and the computer-readable and executable instructions 406, when executed by the processor 402, may cause the system controller 400 to automatically adjust the position of the vent actuator, thereby adjusting the position of the inlet vent 672 based on the item number at the working end 150 of the glass tube 102. The computer-readable and executable instructions 406, when executed by the processor 402, may cause the system controller 400 to send a control signal to the vent actuator indicating the position of the inlet vent 672 depending on the item number at the working end 150 of the glass tube 102.

[0110] The negative pressure generated by the exhaust system 670 can be adjusted per index based on the item number at the working end 150 of the glass tube 102. However, a time lag between changing the exhaust system 670 and the temperature of the glass tube 102 may limit the applicability of adjusting the exhaust system 670 per index (e.g., changing the exhaust system with each index of the converter's main turret). Alternatively, the negative pressure generated by the exhaust system 670 can be adjusted per rotation based on the item number at the working end 150 of the glass tube 102, where the negative pressure generated by the exhaust system 670 is adjusted based on the item number at the working end 150 of the glass tube 102, and the negative pressure generated by the exhaust system 670 is maintained throughout one complete rotation of the converter's main turret 108. Varying the exhaust flow rate may also affect other aspects of the tube converting process, such as the formation of SHR in the glass article, machine evolution, or other factors.

[0111] Referring now to Figure 12, a graph illustrates the effect of exhaust gas flow rate on dimensional variability. Line 1202 represents articles produced with zero exhaust flow. The airflow is gradually increased for articles represented by lines 1204, 1206, and 1208. As shown in Figure 12, increasing the airflow rate can reduce the dimensional variability over the first five articles produced from glass tube 102, as indicated by the decreasing slope of the curve over the first five articles and the decreasing maximum difference between the maximum and minimum average dimensions over those article numbers.

[0112] As previously described, the heating of the glass tube 102 can be adjusted at one or more heating stations 202 based on the item number at the working end of the glass tube 102. Adjusting the heating of the glass tube 102 at multiple heating stations 202 may include adjusting the burner residence time, adjusting the heating rate of a heating element (e.g., burner 302), or adjusting the exhaust flow rate or negative pressure generated by the exhaust system 670 at multiple heating stations 202 of the converter 100. Various combinations of adjusting the burner residence time, the heating rate of the burner 302, or the exhaust flow rate may also be used at one or more heating stations 202 of the converter 100. It should be understood that any combination of these methods may be used at one or more heating stations 202 of the converter 100 to control the variability in the temperature of the glass tube 102 during its consumption in the conversion process. As previously described, the burner residence time, heating rate, exhaust flow, or combinations thereof may be adjusted with each index or each revolution of the converter 100.

[0113] Embodiments of the present disclosure may be embodied in hardware and / or software (including firmware, resident software, microcode, etc.). The converter's system controller 400 and / or other controllers provided in the converter 100 may include at least one processor and computer-readable media (i.e., memory modules), as previously described herein. A computer-usable or computer-readable medium or memory module may be any medium that can contain, store, communicate, propagate, or transfer a program for use by or in connection with an instruction execution system, apparatus, or device.

[0114] A computer-usable or computer-readable medium or memory module may be, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, device, or propagation medium. More specific examples (non-exhaustive list) of computer-readable media include an electrical connection having one or more wires, a portable computer floppy disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), etc. It should be noted that a computer-usable or computer-readable medium may also be paper or other suitable medium on which a program is printed. This is because the program can be electronically captured, for example, by optically scanning the paper or other medium, and then compiled, interpreted, or otherwise processed in an appropriate manner as necessary, and then stored in computer memory.

[0115] The computer-readable medium may include machine-readable and executable instructions for performing the operations of the present disclosure. The machine-readable and executable instructions may include computer program code, which may be written in a high-level programming language such as C or C++ for ease of development. In addition, computer program code for performing the operations of the present disclosure may be written in other programming languages, such as, but not limited to, interpreted languages. Some modules or routines may be written in assembly language or microcode to improve performance and / or memory usage. However, software embodiments of the present disclosure do not depend on implementation in a particular programming language. It should be further understood that any or all functionality of the program modules may be implemented using discrete hardware components, one or more application-specific integrated circuits (ASICs), or a programmed digital signal processor or microcontroller.

[0116] Referring again to FIG. 6 , a method for producing multiple articles from a glass tube 102 may include securing a working end 150 of the glass tube 102 to a glass tube holder 130 of a converter 100 having multiple processing stations 106. The multiple processing stations 106 may include at least one heating station 202 and at least one forming station 204 disposed after the at least one heating station 202. The converter 100 may index the glass tube holder 130 through the multiple processing stations 106. The method may further include indexing the glass tube 102 through each of the multiple processing stations 106. An initial length of the glass tube 102 may include multiple consecutive segments 146. In other words, the glass tube 102 may be conceptually divided into a series of consecutive segments 146. Each of the multiple consecutive segments 146 may correspond to an article, and each article may have an article number. The item number may be an integer that starts at 1 at the initial working end of the glass tube and increases by 1 for each successive consecutive segment 146 up to item number n at the non-working end of the glass tube 102, where n is the total number of items that can be produced from a single length of glass tube 102.

[0117] The method may further include heating the working end 150 of the glass tube 102 at at least one heating station 202. The method may include forming at least one feature of an article on the working end 150 of the glass tube 102 at at least one forming station 204, separating the article from the working end 150 of the glass tube 102 at a separation station 206, and indexing the glass tube 102 downward within the glass tube holder 130 to form a subsequent article. Indexing the glass tube 102 downward may occur before or after separating the article from the working end 150 of the glass tube 102. The method may include increasing or decreasing the amount of heating of the glass tube 102 based on an item number corresponding to the working end 150 of the glass tube 102. Increasing or decreasing the amount of heating of the glass tube 102 based on the item number may reduce variation in tube temperature, article size, or both from a given item number to the next. The variation in tube temperature, article size, or both at the working end 150 of the glass tube 102 may be a function of the article number of the article being formed at the working end 150 of the glass tube 102. The article may be a pharmaceutical container, such as, but not limited to, a vial, cartridge, syringe, ampule, or other pharmaceutical container.

[0118] Increasing or decreasing the amount of heating of the glass tube 102 may include at least one of increasing or decreasing the burner residence time of the working end 150 of the glass tube 102 in contact with a heating element (e.g., burner 302) in at least one heating station 202 based on the item number at the working end 150 of the glass tube 102, increasing or decreasing the heating rate of the heating element or burner 302 in at least one heating station 202 based on the item number at the working end 150 of the glass tube 102, or adjusting the negative pressure or exhaust flow rate generated by an exhaust system 670 proximate to the glass tube 102 in at least one heating station 202 based on the item number at the working end 150 of the glass tube 102.

[0119] In an embodiment, the multiple processing stations 106 may include multiple heating stations 202, and the method may include increasing or decreasing the amount of heating of the glass tube 102, such as at the working end 150 of the glass tube 102, in the multiple heating stations 202 based on an item number corresponding to the working end 150 of the glass tube 102. In an embodiment, the method may include increasing or decreasing the amount of heating of the glass tube 102, such as at the working end 150 of the glass tube 102, in each heating station 202 based on an item number corresponding to the working end 150 of the glass tube 102.

[0120] 7A and 7B, in an embodiment, increasing or decreasing the amount of heating of the glass tube 102 may include increasing or decreasing a burner residence time of the glass tube 102 in contact with a heating element, such as a burner 302, in at least one heating station 202 based on an item number at the working end 150 of the glass tube 102. The heating element in at least one heating station may include a swirl burner 330 that can be swiveled into and out of engagement with the working end 150 of the glass tube 102. In an embodiment, the swirl burner 330 may include a swirl burner actuator 332, and the method includes actuating the swirl burner actuator 332, whereby the swirl burner 330 swirls or moves into and out of engagement with the working end 150 of the glass tube 102 to adjust the burner residence time. In an embodiment, increasing or decreasing the burner residence time may include adjusting the timing at which the swirl burner 330 swirls into or out of engagement with the working end 150 of the glass tube 102.

[0121] Referring again to FIG. 6 , in embodiments, increasing or decreasing the amount of heating of the working end 150 of the glass tube 102 may include increasing or decreasing the heating rate of a heating element in at least one heating station 202 based on the item number at the working end 150 of the glass tube 102. In embodiments, the heating element may include a burner 302 or a swirl burner 330, and increasing or decreasing the heating rate may include increasing or decreasing the flow rate of one or more combustion gases supplied to the burner 302 or the swirl burner 330. The combustion gases may include a fuel gas, oxygen, air, or both. In embodiments, increasing or decreasing the heating rate of the burner 302 or the swirl burner 330 in at least one heating station 202 may include proportionally increasing or decreasing the flow rate of all combustion gases to the burner 302 or the swirl burner 330. The method may include maintaining a constant mass flow ratio of fuel gas to oxygen for combustion gases delivered to the burner 302 or swirl burner 330. In an embodiment, increasing or decreasing the heating rate of the burner 302 or swirl burner 330 in the at least one heating station 202 may include modifying the flow ratio of fuel gas to oxygen supplied to the burner 302 or swirl burner 330.

[0122] 11 , in embodiments, increasing or decreasing the amount of heating of the working end 150 of the glass tube 102 may include adjusting a negative pressure or exhaust flow rate generated by an exhaust system 670 proximate the glass tube 102 in the at least one heating station 202 based on the item number of the working end 150 of the glass tube 102. In embodiments, adjusting a negative pressure or exhaust flow rate generated by an exhaust system 670 proximate the at least one heating station 202 may include increasing or decreasing a speed of an air handler 674 fluidly connected to an inlet vent 672 positioned proximate the at least one heating station 202, adjusting a position of a damper 680 disposed between the air handler 674 and the inlet vent 672, or both. Alternatively or additionally, in an embodiment, adjusting the negative pressure or exhaust flow rate generated by the exhaust system 670 proximate to at least one heating station 202 may include adjusting the position of the inlet vent 672 of the exhaust system 670 relative to the glass tube 102 within the at least one heating station 202.

[0123] Referring to Figures 1 and 6, in an embodiment, the converter 100 may include a plurality of glass tube holders 130, and the method may include indexing each of the plurality of glass tube holders 130 through each of the plurality of processing stations 106, and increasing or decreasing the amount of heating of the working end 150 of the glass tube 102 in at least one heating station 202 based on the item number at the working end 150 of the glass tube 102 each time the plurality of glass tube holders 130 are indexed between the processing stations 106.

[0124] The method may include securing a new length of glass tube 102 in the tube holder 130 after the last item corresponding to the last item number n of glass tubes 102 has been produced. In an embodiment, the converter 100 may include a plurality of glass tube holders 130, and the method may further include securing a new length of glass tube 102 in each of the plurality of glass tube holders 130 in consecutive order, starting with the first glass tube. In other words, the method may include successively replacing the glass tubes 102 in the glass tube holders 130, one after the other. In response to a change in the item number of the working end 150 of the first glass tube at the at least one heating station 202, the method may further include changing the amount of heating of the working end 150 of the first glass tube based on the item number, and maintaining the amount of heating at the at least one heating station 202 from glass tube 102 to glass tube 102 until the first glass tube returns to the at least one heating station 202 and the item number of the working end 150 of the first glass tube changes.

[0125] 1 and 6 , a method of manufacturing multiple articles from a glass tube 102 may include introducing the glass tube 102 into a glass tube holder 130 of a converter 100 having multiple processing stations 106. The multiple processing stations 106 may include at least one heating station 202 and at least one forming station 204 disposed after the at least one heating station 202. The converter 100 may index the glass tube holder 130 through the multiple processing stations 106. The method may include heating a working end 150 of the glass tube 102 at the at least one heating station 202 and forming at least one feature of a first article on the working end 150 of the glass tube 102 at the at least one forming station 204. The first article may correspond to a first sequential position along a length L of the glass tube 102. The method may include separating a first article from a working end 150 of the glass tube 102 at a separation station 106 located after the forming station 204 and indexing the glass tube 102 downward within the glass tube holder 130 to form a second article from the glass tube 102. The second article may correspond to a second successive position along the length of the glass tube 102. The glass tube 102 may be indexed downward before or after separation. The method may include heating the working end 150 of the glass tube 102 corresponding to the second successive position at at least one heating station 202 and increasing or decreasing the amount of heating of the working end 150 of the glass tube 102 corresponding to the second successive position relative to the heating of the first article. Increasing or decreasing the amount of heating of the working end 150 of the glass tube 102 of the second article relative to the first article may reduce the temperature or dimensional variability of the second article relative to the first article. Heating of the glass tube 102 can be increased or decreased according to any of the methods or techniques previously described herein. [Example]

[0126] The following examples illustrate the operation of the disclosed system and method for producing multiple glass articles from a glass tube with a converter. The following examples are not intended to limit the scope of the present disclosure.

[0127] The following examples illustrate the use of the disclosed systems and methods to reduce the variability in the dimensions and appearance of articles made from glass tubes by reducing the variability in the glass tube temperature as the glass tube is gradually consumed during the conversion process. The glass tubes in these examples were aluminosilicate glass tubes, such as VALOR™ glass manufactured and sold by Corning Incorporated. Aluminosilicate glass tubes can be further processed after conversion by annealing and / or ion-exchanging the glass tube.

[0128] Burner Residence Time—Comparative Examples 1 and 2 and Example 3 The effect of burner residence time on the variability of glass article dimensions made from the glass tubes was investigated for Comparative Examples 1 and 2 and Example 3. The aluminosilicate glass tubes were converted into glass vials using a converter. The aluminosilicate glass tubes were VALOR™ glass tubes manufactured by Corning Incorporated. The converter used was a vial-forming machine model RP16 with an automatic tube feeder manufactured by AMBEG Dr. J. Dichter GmbH, which includes 16 processing stations in the main circuit and 8 secondary processing stations in the secondary circuit. A description of the processing stations in the main circuit of the converter used in Example 1 is provided in Table 1 below.

[0129] [Table 1]

[0130] For Comparative Example 1, glass vials were produced without adding auxiliary heating to the converter. For Comparative Example 2 and Example 3, a swirl burner was installed at processing station A2. For Comparative Example 2, glass vials were produced with auxiliary heating for a set period of time at processing station A2. The auxiliary heating for a set duration in Comparative Example 2 was provided by a swirl burner with a fixed residence time at processing station A2. For Example 3, glass vials were produced based on the item number at the working end of the glass tube, while the burner residence time of the swirl burner was changed from that of Comparative Example 2. For Comparative Examples 1, 2, and Example 3, the mass flow rate of combustion gas to the burner was maintained constant, resulting in a constant burner heating rate. Only the contact time of the burner flame with the glass tube was changed.

[0131] A total of 16 tubes were loaded into the converter. Thus, for each item number, 16 items were produced per revolution of the converter. The resulting values ​​of a specific dimension of the item (y-axis) as a function of item number (x-axis) are shown graphically in FIG. 8. Data for Comparative Example 1 are shown as circles, with line 502 representing the average of all 16 items for each item number. Data for Comparative Example 2 are shown as triangles, with line 504 representing the average of all 16 items for each item number. Data for Example 3 are shown as squares, with line 506 representing the average of all 16 items for each item number for Example 3.

[0132] As shown in FIG. 8 , for Comparative Example 1 (line 502), the article dimensions vary significantly from the first article through the nth article (article 29). In particular, as the tube temperature increases, the article dimensions change rapidly over the first few articles. The dimensions plateau for a few more articles before changing rapidly again beyond article number 12. The given amount of heat applied in Comparative Example 2 (line 504) resulted in deviations in article dimensions compared to those produced in Comparative Example 1, but followed the same general trend of significant dimensional change over the first five or six vials as the tube heated, followed by additional variability in dimensions after article 12. While not wishing to be bound by theory, it is believed that this is because the tube temperature changes over multiple transducer revolutions, changing the viscosity of the tube and resulting in dimensional deviations. However, Comparative Example 2 demonstrates that varying the amount of heat applied can change the dimensions of vials produced from the tube.

[0133] In Example 3 (line 506), the heat dose is adjusted based on the item number at the working end of the glass tube for each index. As shown by line 506, adjusting the heat dose based on the item number at the working end of the glass tube reduces the variability in the dimensions of the glass articles produced from the glass tube. In particular, for line 506, the significant change in the dimensions of the glass tube over the first five articles can be significantly reduced and / or eliminated. By adding the adjustment of the heat dose based on the item number in Example 3, the variability of the glass article dimensions was reduced to about one-third or even less than one-third of the variability of the dimensions of Comparative Example 1, where the heat dose was not adjusted. Without intending to be bound by any particular theory, it is believed that further reduction in the dimensional variability of Example 3 can be achieved by further enhancing the control algorithm to track the item number and adjust the burner residence time based on the item number.

[0134] Heating Rate—Comparative Example 4 and Example 5 In Comparative Example 4 and Example 5, the effect of adjusting the heating rate of the burner in the heating station based on the article number at the working end of the glass tube on the variability of the dimensions of the glass articles produced from the glass tube was investigated. Aluminosilicate glass tubes were converted to glass vials using the converter described in Comparative Example 1 above. For Comparative Example 4, the heating rate of the burner in the heating station was kept constant by maintaining the mass flow rate of combustion gases (fuel and oxygen) to the burner constant at a constant fuel-to-oxygen ratio. For Example 5, the heating rate of the burner was adjusted based on the article number at the working end of the glass tube by increasing or decreasing the mass flow rate of combustion gases at a constant fuel-to-oxygen ratio based on the article number at the working end of the glass tube.

[0135] The glass tube temperature in the heating station as a function of time is shown in FIG. 9 for Comparative Example 4 and Example 5. In FIG. 9, time equal to zero represents the end of the index time of the converter 100 and the point at which the glass tube 102 reaches a rest position in the heating station 202. Under a constant combustion gas flow rate for Comparative Example 4 (line 902), the glass tube temperature increased over time. For Example 5 (line 904), the flow rate of combustion gas to the burner in the heating station was gradually increased at time equal to zero. As shown in FIG. 9, a delayed response of the glass tube temperature to changes in the combustion gas flow rate to the burner was observed. Initially, when the combustion gas flow rate was changed at time equal to zero, the glass tube temperature (904) for Example 5 continued to increase at the same rate as the glass tube temperature (902) for Comparative Example 4. Approximately 0.5 seconds after changing the burner heating rate, the effect of changing the combustion gas flow rate began to be felt, and the glass tube temperature began to increase. This is shown by the deviation of line 904 from line 902, which begins about 0.5 seconds after time equals zero. The heating rate of the burner 302 takes time to increase to its final heating rate after the combustion gas flow rate is changed. This is shown in FIG. 9 by the period from 0.5 seconds to about 0.8 seconds, during which the slope of the temperature change is greater than the slope of the temperature change after 0.8 seconds. This indicates a delayed response of the glass tube temperature to the combustion gas flow rate change.

[0136] 10A graphically illustrates the dimensions (y-axis) of articles produced from the glass tubes as a function of article number (x-axis) for Comparative Example 4, where the burner heating rate was held constant. As shown in FIG. 10A, without changing the burner heating rate to compensate for the variation in glass tube temperature based on article number, the average dimensions of the articles change dramatically over the first 10-15 articles produced.

[0137] In Example 5, the glass tubes were loaded into each holder in sequential order, and the burner heating rate was adjusted once per revolution of the converter's main turret. FIG. 10B graphically illustrates the dimensions of the articles produced from the glass tubes (y-axis) as a function of the article number (x-axis) for Example 5, in which the burner heating rate was adjusted per revolution based on the article number at the working end of the glass tube. As shown in FIG. 10B, adjusting the burner heating rate in the heating station per revolution based on the article number at the working end of the glass tube significantly reduces the variability in the dimensions of the articles produced from the glass tubes, particularly over the first 10-15 articles produced from each glass tube 102. As shown by comparing FIGS. 10A and 10B, the variability in the dimensions of the articles produced can be reduced by 80% by adjusting the burner heating rate in the heating station per revolution based on the article number at the working end of the glass tube. Thus, by varying the heating rate of one or more burners in one or more heating stations based on the article number at the working end of the glass tube, variability in the dimensions and appearance of the finished article can be reduced.

[0138] Exhaust Stream - Examples 6 to 9 For Examples 6-9, the effect on the variability of glass article dimensions produced from glass tubes of adjusting the exhaust air flow rate proximate the heating station based on the article number at the working end of the glass tube was investigated. Aluminosilicate glass tubes were converted to glass vials using the converter described in Comparative Example 1 above. In Example 6, the converter was operated without exhaust air flow at the heating station. For each of Examples 7-9, the exhaust air flow proximate the heating station was maintained constant throughout the consumption of the entire glass tube. The air flows and reference numbers from Figure 12 corresponding to Examples 6-9 are provided in Table 2 below.

[0139] [Table 2]

[0140] FIG. 12 graphically illustrates parameters showing glass vial size (y-axis) as a function of item number (x-axis) for Examples 6-9. As shown in FIG. 12, the exhaust flow rate proximate to the heating station can affect the variability of glass vial size. Size shifts can also be achieved by varying the exhaust flow rate proximate to the heating station. These effects can be used to manipulate the glass tube temperature at the working end during heating, compensating for glass tube temperature changes during consumption of the glass tube over multiple revolutions of the transducer.

[0141] While various embodiments of the converter 100, systems and methods for producing multiple articles from glass tube 102 have been described herein, it is understood that it is contemplated that each of these embodiments and techniques may be used separately or in conjunction with one or more other embodiments and techniques.

[0142] It will be apparent to those skilled in the art 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. Thus, it is intended that the present specification cover the modifications and variations of the various embodiments described herein, provided they come within the scope of the appended claims and their equivalents.

[0143] Preferred embodiments of the present invention will be described below in detail.

[0144] Embodiment 1 1. A method for producing a plurality of articles from a glass tube, comprising: securing the working end of the glass tube in a glass tube holder of a converter having a plurality of processing stations, the processing stations including at least one heating station and at least one forming station subsequent to the at least one heating station, the converter moving the glass tube holder through the plurality of processing stations, the initial length of the glass tube comprising a plurality of successive segments, each of the plurality of successive segments corresponding to an item and having an item number; heating the working end of the glass tube in the at least one heating station; increasing or decreasing the amount of heat applied to the glass tube based on the item number corresponding to the working end of the glass tube, wherein increasing or decreasing the amount of heat applied based on the item number reduces variation in tube temperature, item size, or both from a given item number to the next; forming at least one feature of the article on the working end of the glass tube at the at least one forming station; separating the article from the working end of the glass tube at a separation station; indexing the glass tube downward within the glass tube holder to form a next article; A method comprising:

[0145] Embodiment 2 The step of increasing or decreasing the amount of heating of the glass tube comprises: increasing or decreasing a burner residence time of the working end of the glass tube in contact with a heating element in the at least one heating station based on the item number at the working end of the glass tube; increasing or decreasing the heating rate of the heating element in the at least one heating station based on the item number of the working end of the glass tube; or adjusting a negative pressure generated by an exhaust system proximate to the glass tube in the at least one heating station based on the item number of the working end of the glass tube. 2. The method of embodiment 1, comprising at least one of:

[0146] Embodiment 3 The method of embodiment 1, wherein the plurality of processing stations comprises a plurality of heating stations, and the method includes a step of increasing or decreasing the amount of heating of the glass tube at each of the plurality of heating stations based on the item number corresponding to the working end of the glass tube.

[0147] Embodiment 4 The method of embodiment 1, wherein the step of increasing or decreasing the amount of heating at the working end of the glass tube includes increasing or decreasing the burner residence time of the glass tube in contact with a heating element in the at least one heating station based on the item number at the working end of the glass tube.

[0148] Embodiment 5 The method of embodiment 4, wherein the heating element in at least one heating station comprises a swirl burner that swirls to engage or disengage the working end of the glass tube, and the step of increasing or decreasing the burner residence time includes adjusting the timing at which the swirl burner swirls to engage or disengage the working end of the glass tube.

[0149] Embodiment 6 The method of embodiment 1, wherein the step of increasing or decreasing the amount of heating at the working end of the glass tube includes the step of increasing or decreasing the heating rate of a heating element in the at least one heating station based on the item number of the working end of the glass tube.

[0150] Embodiment 7 7. The method of embodiment 6, wherein the heating element comprises a burner, and wherein increasing or decreasing the heating rate comprises increasing or decreasing a flow rate of one or more combustion gases supplied to the burner, the combustion gases comprising a fuel gas and oxygen, air, or both.

[0151] Embodiment 8 8. The method of embodiment 7, wherein increasing or decreasing the heating rate comprises proportionally increasing or decreasing the flow rate of all of the combustion gases to the burner.

[0152] Embodiment 9 The method of embodiment 1, wherein the step of increasing or decreasing the amount of heating at the working end of the glass tube includes adjusting the negative pressure generated by an exhaust system proximate to the at least one heating station based on the item number of the working end of the glass tube.

[0153] Embodiment 10 The method of embodiment 9, wherein adjusting the negative pressure generated by the exhaust system proximate to the at least one heating station includes decreasing or increasing the speed of an air handler fluidly connected to an inlet vent positioned proximate to the at least one heating station, adjusting the position of a damper positioned between the air handler and the inlet vent, adjusting the position of the inlet vent of the exhaust system relative to the glass tube in the at least one heating station, or a combination of these steps.

[0154] Embodiment 11 The transducer comprises a plurality of glass tube holders, and the method includes: moving each of the plurality of glass tube holders through each of the plurality of processing stations; increasing or decreasing the amount of heat applied to the working ends of the glass tubes based on the item numbers each time the plurality of glass tube holders move to the next processing station; 2. The method of embodiment 1, comprising:

[0155] Embodiment 12 The method of embodiment 1, wherein the converter comprises a plurality of glass tube holders, and the method further comprises the step of fixing the new length of the glass tube to each of the plurality of glass tube holders in consecutive order, starting with the first glass tube.

[0156] Embodiment 13 The method of claim 12, further comprising: changing the amount of heating at the working end of the first glass tube based on the item number in response to a change in the item number at the working end of the first glass tube at the at least one heating station; and maintaining the amount of heating at the at least one heating station from glass tube to glass tube until the first glass tube returns to the at least one heating station and the item number at the working end of the first glass tube changes.

[0157] Embodiment 14 1. A system for producing a plurality of articles from glass tubing, comprising: a converter including a plurality of processing stations, including at least one heating station, at least one forming station, and a separation station, the converter being operable to move the glass tube through the plurality of processing stations; a system controller communicatively connected to the converter, the system controller comprising a processor and a storage medium containing computer readable and executable instructions, the instructions, when executed by the processor, causing the system controller to automatically: determining an item number at the working end of the glass tube, the item number including integers corresponding to successive segments of the initial length of the glass tube, each successive segment corresponding to an item; increasing or decreasing the amount of heating of the glass tube at the at least one heating station based on the item number at the working end of the glass tube. System Controller and Including, the system.

[0158] Embodiment 15 The system of embodiment 14, wherein the at least one heating station comprises a swirl burner operable to swirl into and out of engagement with the working end of the glass tube, and the system controller is communicatively connected to the swirl burner.

[0159] Embodiment 16 The system of embodiment 15, wherein the computer-readable and executable instructions, when executed by the processor, cause the system controller to automatically increase or decrease the burner residence time at the working end of the glass tube based on the item number at the working end of the glass tube by pivoting the swirl burner into or out of engagement with the working end of the glass tube.

[0160] Embodiment 17 15. The system of embodiment 14, wherein the at least one heating station comprises at least one burner and at least one flow controller operable to increase or decrease the mass flow rate of one or more combustion gases to the at least one burner.

[0161] Embodiment 18 18. The system of claim 17, wherein the computer-readable and executable instructions, when executed by the processor, cause the system controller to automatically increase or decrease the mass flow rate of one or more combustion gases to the at least one burner based on the item number at the working end of the glass tube.

[0162] Embodiment 19 15. The system of embodiment 14, wherein the converter comprises an exhaust system comprising at least one inlet vent and an air handler fluidly connected to the at least one inlet vent.

[0163] Embodiment 20 The system of embodiment 19, wherein the computer-readable and executable instructions, when executed by the processor, cause the system controller to automatically adjust the negative pressure generated by the exhaust system adjacent to the glass tube based on the item number of the working end of the glass tube.

Claims

1. 1. A method for producing a plurality of articles from a glass tube, comprising: securing the working end of the glass tube in a glass tube holder of a converter having a plurality of processing stations including at least one heating station and at least one forming station subsequent to the at least one heating station, the converter moving the glass tube holder through the plurality of processing stations, the initial length of the glass tube comprising a plurality of successive segments, each of the plurality of successive segments corresponding to an article and having an article number; heating the working end of the glass tube in the at least one heating station; increasing or decreasing the amount of heat applied to the glass tube based on the item number corresponding to the working end of the glass tube, wherein increasing or decreasing the amount of heat applied based on the item number reduces variation in tube temperature, item size, or both from a given item number to the next; forming at least one feature of the article on the working end of the glass tube at the at least one forming station; separating the article from the working end of the glass tube at a separation station; indexing the glass tube downward within the glass tube holder to form a next article; A method comprising:

2. The step of increasing or decreasing the amount of heating of the glass tube comprises: increasing or decreasing a burner residence time of the working end of the glass tube in contact with a heating element in the at least one heating station based on the item number at the working end of the glass tube; increasing or decreasing the heating rate of the heating element in the at least one heating station based on the item number of the working end of the glass tube; or adjusting a negative pressure generated by an exhaust system proximate to the glass tube in the at least one heating station based on the item number of the working end of the glass tube. The method of claim 1 , comprising at least one of:

3. 2. The method of claim 1, wherein the plurality of processing stations comprises a plurality of heating stations, and the method includes a step of increasing or decreasing the amount of heat applied to the glass tube at each of the plurality of heating stations based on the item number corresponding to the working end of the glass tube.

4. 2. The method of claim 1, wherein increasing or decreasing the amount of heating at the working end of the glass tube comprises increasing or decreasing a burner residence time of the glass tube in contact with a heating element in the at least one heating station based on the item number at the working end of the glass tube.

5. 2. The method of claim 1, wherein increasing or decreasing the amount of heating at the working end of the glass tube comprises increasing or decreasing a heating rate of a heating element in the at least one heating station based on the item number of the working end of the glass tube.

6. 6. The method of claim 5, wherein the heating element comprises a burner, and wherein increasing or decreasing the heating rate comprises increasing or decreasing a flow rate of one or more combustion gases supplied to the burner, the combustion gases comprising a fuel gas and oxygen, air, or both.

7. 2. The method of claim 1, wherein increasing or decreasing the amount of heating at the working end of the glass tube comprises adjusting a negative pressure generated by an exhaust system proximate to the at least one heating station based on the item number of the working end of the glass tube.

8. 8. The method of claim 7, wherein adjusting the negative pressure generated by the exhaust system proximate to the at least one heating station comprises decreasing or increasing the speed of an air handler fluidly connected to an inlet vent positioned proximate to the at least one heating station, adjusting the position of a damper disposed between the air handler and the inlet vent, adjusting the position of an inlet vent of the exhaust system relative to the glass tube in the at least one heating station, or a combination of these steps.

9. The transducer comprises a plurality of glass tube holders, and the method includes: moving each of the plurality of glass tube holders through each of the plurality of processing stations; increasing or decreasing the amount of heat applied to the working ends of the glass tubes based on the item numbers each time the plurality of glass tube holders move to the next processing station; 2. The method of claim 1, comprising:

10. the converter comprises a plurality of glass tube holders, the method further comprising securing the new length of glass tube to each of the plurality of glass tube holders in consecutive order, starting with a first glass tube; 2. The method of claim 1, further comprising: varying the amount of heating at the working end of the first glass tube based on the item number in response to a change in the item number at the working end of the first glass tube at the at least one heating station; and maintaining the amount of heating at the at least one heating station from glass tube to glass tube until the first glass tube returns to the at least one heating station and the item number at the working end of the first glass tube changes.

11. 1. A system for producing a plurality of articles from glass tubing, comprising: a converter including a plurality of processing stations, including at least one heating station, at least one forming station, and a separation station, the converter being operable to move the glass tube through the plurality of processing stations; a system controller communicatively connected to the converter, the system controller comprising a processor and a storage medium containing computer readable and executable instructions, the instructions, when executed by the processor, causing the system controller to automatically: determining an item number at the working end of the glass tube, the item number including integers corresponding to successive segments of the initial length of the glass tube, each successive segment corresponding to an item; increasing or decreasing the amount of heating of the glass tube at the at least one heating station based on the item number at the working end of the glass tube. System Controller and Including, the system.

12. The system of claim 11, wherein the at least one heating station comprises a swirl burner operable to swirl into and out of engagement with the working end of the glass tube, and the system controller is communicatively connected to the swirl burner.

13. 13. The system of claim 12, wherein the computer-readable and executable instructions, when executed by the processor, cause the system controller to automatically increase or decrease burner residence time at the working end of the glass tube based on the item number at the working end of the glass tube by swiveling the swirl burner into or out of engagement with the working end of the glass tube.

14. The system of claim 11 , wherein the at least one heating station comprises at least one burner and at least one flow controller operable to increase or decrease a mass flow rate of one or more combustion gases to the at least one burner.

15. 15. The system of claim 14, wherein the computer-readable and executable instructions, when executed by the processor, cause the system controller to automatically increase or decrease the mass flow rate of one or more combustion gases to the at least one burner based on the item number at the working end of the glass tube.

16. The system of claim 11 , wherein the converter comprises an exhaust system comprising at least one inlet vent and an air handler fluidly connected to the at least one inlet vent.

17. 17. The system of claim 16, wherein the computer-readable and executable instructions, when executed by the processor, cause the system controller to automatically adjust the negative pressure generated by the exhaust system adjacent to the glass tube based on the item number of the working end of the glass tube.

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