BACKGROUND

Field

The present specification generally relates to systems and methods for producing glass articles from glass tubes, in particular systems and methods for reducing Surface Hydrolytic Response (SHR) of the glass article resulting from conversion of the glass tube.

Technical Background

Historically, glass has been used as the preferred material for packaging pharmaceuticals because of its hermeticity, optical clarity, and excellent chemical durability relative to other materials. Specifically, the glass used in pharmaceutical packaging must have adequate chemical durability so as to not affect the stability of the pharmaceutical formulations contained therein. Glasses having suitable chemical durability include those glass compositions within the ASTM standard ‘Type IA’ and ‘Type IB’ glass compositions which have a proven history of chemical durability.

The chemical durability of a glass, as used herein, refers to the ability of the glass to resist degradation upon exposure to specified chemical conditions. One measure of the chemical durability of the glass is the Surface Hydrolytic Response (SHR) of the glass, which can be thought of as a measure of the chemical stability of the glass when contacted with a pharmaceutical composition. The SHR of the glass can be assessed according to one of three analytical tests described in United States Pharmacopiea (USP) <660> entitled “Containers-Glass 1”: the Glass Grains Test, the Surface Glass Test, and the Surface Etching Test. Other tests to assess the SHR of glass may include: DIN 12116 dated March 2001 and entitled “Testing of glass—Resistance to attack by a boiling aqueous solution of hydrochloric acid—Method of test and classification”; ISO 695:1991 entitled “Glass—Resistance to attack by a boiling aqueous solution of mixed alkali—Method of test and classification”; and ISO 720:1985 entitled “Glass—Hydrolytic resistance of glass grains at 121 degrees C.—Method of test and classification.” The chemical durability of the glass may also be assessed according to ISO 719:1985 “Glass—Hydrolytic resistance of glass grains at 98 degrees C.—Method of test and classification,” in addition to the above referenced standards.

Glass tubing may be converted into other glass articles, such as various glass containers for use in pharmaceutical applications including, without limitation, vials, syringes, ampoules, cartridges and other glass articles. The glass tubing may be converted, for example, in “converting machines.” Converting machines have been used for over 75 years, and are currently made by various commercial and internal equipment suppliers. These converting machines typically reform long glass tube lengths into a plurality of glass articles using steps which include flame working, rotating and stationary tool forming, thermal separation, or score and shock cutoff steps.

During certain flame working operations that occur in the converting machine during the converting process, the glass tube may be heated to temperatures sufficient to vaporize one or more volatile constituents of the glass composition. Gas containing volatiles are injected into the working tube's interior in piercing. Effects from exhaust systems, burners, buoyancy-driven chimney flow, and cooling jets can move the volatile-containing gases in the tube interior, causing them to move upward, downward or to stagnate. These vaporized chemical components can condense on the cooler interior surfaces of the glass tube, which cause an increase in the SHR of the glass article.

SUMMARY

Accordingly, a need exists for systems and methods for converting glass tubes into glass articles, such as pharmaceutical packaging, while maintaining the surface hydrolytic resistance of the glass articles.

In a first aspect of the present disclosure, a method for producing an article from a glass tube having an inner surface may include introducing the glass tube to a converter having a plurality of processing stations comprising at least one heating station and at least one forming station and heating a proximal end of the glass tube at the at least one heating station. Alkali is released from the glass tube during the heating. The method may further include forming at least one feature of the article at the proximal end of the glass tube in the at least one forming station, separating the article from the proximal end of the glass tube at a separating station, and producing a flow of gas adjacent to the proximal end of the glass tube. The flow of gas may be operable to remove at least a portion of the atmosphere in an interior of the glass tube.

In a second aspect of the present disclosure, a method for producing an article from glass tubing may include, introducing a glass tube to a converter having a plurality of processing stations comprising at least one heating station, at least one forming station, and a separating station and heating a proximal end of the glass tube at the at least one heating station. Alkali is released from the glass tube during the heating. The method may further include forming at least one feature of the article at the proximal end of the glass tube in the at least one forming station, separating the article from the proximal end of the glass tube at the separating station, and producing a gas pulse adjacent to the proximal end of the glass tube. The gas pulse may produce a flow of gas adjacent to the proximal end of the glass tube that may be operable to remove at least a portion of the atmosphere in an interior of the glass tube and reduce contamination of an inner surface of the glass tube by the alkali released from the glass tube.

A third aspect of the present disclosure may include the second aspect, wherein separating the article from the glass tube may produce a meniscus of glass across the proximal end of the glass tube and the gas pulse is sufficient to open the meniscus.

A fourth aspect of the present disclosure may include either of the second or third aspects, further comprising adjusting a flow rate or volume of the gas pulse in response to changes in a length of the glass tube.

A fifth aspect of the present disclosure may include any of the second through fourth aspects, further comprising controlling at least one of a duration of the gas pulse, a pressure of the gas pulse, or a volume flow rate of the gas pulse in response to changes in the tube diameter, wall thickness, glass type, converter operating temperatures, or combinations of these.

In a sixth aspect of the present disclosure, a system for producing glass articles from glass tubing may include a converter including a plurality of processing stations that include at least one heating station, at least one forming station, and a separating station. The converter may be operable to index a glass tube through the plurality of processing stations. The system may further include a gas flow system operable to produce a flow of gas adjacent to a proximal end of the glass tube. Producing the flow of gas at the proximal end of the glass tube may be operable to remove at least a portion of an atmosphere from the interior of the glass tube and reduce contamination of an inner surface of the glass tube by alkali released from the glass tube.

A seventh aspect of the present disclosure may include the sixth aspect, wherein the gas flow system may be operable to introduce a gas pulse to a distal end of the glass tube.

An eighth aspect of the present disclosure may include the seventh aspect, wherein the gas pulse may have a duration less than a sum of an index time and a dwell time of the converter.

A ninth aspect of the present disclosure may include any of the sixth through eighth aspects, wherein the gas flow system may further comprise at least one flow controller operable to vary a flow rate of the flow of gas adjacent to the proximal end of the glass tube in response to changes in a length of the glass tube.

A tenth aspect of the present disclosure may include any of the sixth through ninth aspects, wherein the gas flow system may comprise a gas source and at least one gas delivery assembly coupled to at least one processing station or to at least one of a plurality of holders of the converter, the at least one gas delivery assembly comprising a nozzle positioned to deliver a gas from the gas source into a distal end of a glass tube.

An eleventh aspect of the present disclosure may include the tenth aspect, wherein the at least one gas delivery assembly may further comprise a valve fluidly coupled to the nozzle and coupleable to the gas source, and a valve actuator operatively coupled to the valve.

A twelfth aspect of the present disclosure may include either of the tenth or eleventh aspects, wherein the at least one gas delivery assembly may comprise a positioner coupled to the nozzle and operable to position the nozzle relative to the distal end of the glass tube.

A thirteenth aspect of the present disclosure may include the twelfth aspect, wherein the positioner may comprise a rail and a bracket movable along the rail, wherein the nozzle may be coupled to the bracket.

A fourteenth aspect of the present disclosure may include any of the tenth through thirteenth aspects, wherein the nozzle may be positioned vertically above the distal end of the glass tube, the nozzle operable to deliver the gas directly into the distal end of the glass tube.

A fifteenth aspect of the present disclosure may include any of the tenth through fourteenth aspects, wherein the nozzle may be spaced apart from the distal end of the glass tube by a distance from 1 mm to 15 mm.

A sixteenth aspect of the present disclosure may include any of the tenth through fifteenth aspects, wherein the gas flow system may comprise a plurality of gas delivery assemblies, each of the plurality of gas delivery assemblies positioned at one of a piercing station, the separating station, the at least one heating station, or the at least one forming station.

A seventeenth aspect of the present disclosure may include any of the tenth through sixteenth aspects, wherein the separating station may be a thermal separating station, at least one gas delivery assembly is positioned at a piercing station of the converter after the thermal separating station, and the gas flow system is operable to produce a flow of gas sufficient to open a meniscus of glass formed on the proximal end of the glass tube in the thermal separating station.

An eighteenth aspect of the present disclosure may include any of the sixth through ninth aspects, wherein the gas flow system may comprise a gas source and an enclosure fluidly coupled to the gas source, the enclosure positioned to enclose a distal end of the glass tube, wherein an internal volume of the enclosure may be in fluid communication with the distal end of the glass tube when the glass tube is enclosed within the enclosure, and the gas flow system may be operable to pass a gas from the gas source, into the enclosure, and into the distal end of the glass tube.

A nineteenth aspect of the present disclosure may include the eighteenth aspect, wherein the gas flow system may further comprise a valve fluidly coupled to the enclosure and the gas source and a valve actuator operatively coupled to the valve, wherein the valve actuator may be operable to open and close the valve to deliver a gas pulse to the distal end of the glass tube.

A twentieth aspect of the present disclosure may include either of the eighteenth or nineteenth aspects, wherein the gas flow system may further comprise at least one flow meter disposed between the gas source and the enclosure, the at least one flow meter operable to measure a flow rate of the gas passed from the gas source to the distal end of the glass tube.

A twenty-first aspect of the present disclosure may include any of the eighteenth through twentieth aspects, wherein the gas flow system may further comprise at least one flow controller operable to vary a flow rate of the gas in response to changes in a length of the glass tube.

A twenty-second aspect of the present disclosure may include any of the eighteenth through twenty-first aspects, wherein the gas flow system may be operable to deliver a gas pulse into the distal end of the glass tube.

A twenty-third aspect of the present disclosure may include any of the eighteenth through twenty-second aspects, wherein the gas flow system may comprise a plurality of enclosures, each of the plurality of enclosures coupled to one of a plurality of holders of the converter to enclose the distal end of the glass tube secured in one of the plurality of holders.

A twenty-fourth aspect of the present disclosure may include the twenty-third aspect, further comprising a manifold having a plurality of gas connections, wherein each of the plurality of enclosures may be in fluid communication with one of the plurality of gas connections.

A twenty-fifth aspect of the present disclosure may include the twenty-fourth aspect, wherein the manifold may comprise a plurality of valves and a plurality of valve actuators, each of the plurality of valves fluidly coupled to one of the plurality of enclosures, wherein each of the valve actuators may be operatively coupled to one of the plurality of valves and each valve actuator may be operable to open and close the associated valve to deliver a gas pulse to one of the plurality of the enclosures.

A twenty-sixth aspect of the present disclosure may include either of the twenty-fourth or twenty-fifth aspects, wherein the gas flow system may further comprise at least one flow meter fluidly coupled to the manifold and operable to measure a flow rate or a total flow of the gas passed from the gas source to at least one of the plurality of enclosures.

A twenty-seventh aspect of the present disclosure may include any of the twenty-fourth through twenty-sixth aspects, wherein the gas flow system may further comprise at least one flow controller operable to vary a flow rate of the gas in response to changes in a length of the glass tube.

A twenty-eighth aspect of the present disclosure may include any of the eighteenth through twenty-seventh aspects, wherein the enclosure may be coupleable to an exterior surface the glass tube.

A twenty-ninth aspect of the present disclosure may include any of the sixth through twenty-eighth aspects, wherein the gas flow may be directed orthogonal to a longitudinal axis of the glass tube.

A thirtieth aspect of the present disclosure may include any of the sixth through twenty-eighth aspects, wherein the gas flow may be produced external from the glass tube and at a nonzero angle with a longitudinal axis of the glass tube.

In a thirty-first aspect of the present disclosure, a system for producing glass articles from glass tube may include a converter including a plurality of processing stations comprising at least one heating station, at least one forming station, and a separating station, wherein the converter may be operable to index a glass tube through the plurality of processing stations. The system may further include a gas flow system comprising a gas source and at least one gas delivery assembly fluidly coupled to the gas source and positioned to introduce a gas pulse into a distal end of the glass tube. Introducing the gas pulse to the distal end of the glass tube may produce a flow of gas through an interior of the glass tube from the distal end to a proximal end of the glass tube, wherein the flow of gas may be operable to remove at least a portion of an atmosphere from the interior of the glass tube and reduce contamination of an inner surface of the glass tube by alkali released from the glass tube.

In a thirty-second aspect of the present disclosure, a system for producing glass articles from glass tube may include a converter including a plurality of processing stations that may include at least one heating station, at least one forming station, and a separating station. The converter may be operable to index a glass tube through the plurality of processing stations. The system may further include a gas flow system operable to produce a negative pressure adjacent to a proximal end of the glass tube. The negative pressure may be operable to evacuate at least a portion of the atmosphere from the interior of the glass tube.

In a thirty-third aspect of the present disclosure, a system for producing glass articles from glass tubing may include a converter including a plurality of processing stations that include at least one heating station, at least one forming station, and a separating station. The converter may be operable to index a glass tube through the plurality of processing stations. The system may further include a gas flow system that includes a manifold fluidly couplable to a gas source, and a plurality of glass tube connectors, each glass tube connector removably coupleable to a distal end of the glass tube and fluidly coupled to the manifold by a conduit. For at least one of the glass tube connectors, the gas flow system may be operable to pass a gas from the manifold, through the conduit, through the glass tube connector, and into the distal end of the glass tube, and passing the gas into the distal end of the glass tube may produce a flow of gas adjacent to a proximal end of the glass tube. The flow of gas may be operable to remove at least a portion of an atmosphere from an interior of the glass tube and reduce contamination of an inner surface of the glass tube by alkali released from the glass tube.

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 character 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 the various embodiments described herein, and together with the description serve to explain the principles and operations of the claimed subject matter.

