Abstract
A process for preparing a glass container that includes: providing a glass tube with a first portion, a second portion, and a longitudinal axis (L.sub.tube); holding the first portion in a first clamping chuck and the second portion in a second clamping chuck; rotating the glass tube around the longitudinal axis (L.sub.tube); heating, via a heater, the glass tube above a glass transition temperature; separating the first and second portions from one another by pulling apart along the longitudinal axis (L.sub.tube) while the heated glass tube is still rotating by moving the first and the second chucks away from each other; and moving the heater, while moving the first and second chucks away from each other, so that the heater follows a mass that remains at a circular end region of the first and/or second portion.
Claims
1. A process for the preparation of a glass container from a glass tube, comprising the steps of: providing a glass tube with a first portion, a second portion, and a longitudinal axis (L.sub.tube) that passes through a centre of the glass tube; holding the first portion in a first clamping chuck and the second portion in a second clamping chuck; rotating the glass tube around the longitudinal axis (L.sub.tube) while the glass tube is held in the first and second clamping chucks; heating the glass tube, via at least one heater, between the first and second portions to a temperature above a glass transition temperature while the glass tube is rotating around the longitudinal axis (L.sub.tube); separating the first and second portions from one another by pulling apart in a direction along the longitudinal axis (L.sub.tube) while the heated glass tube is still rotating around the longitudinal axis (L.sub.tube) by moving the first and second clamping chucks away from each other; and moving the at least one heater, while moving the first and second clamping chucks, along the longitudinal axis (L.sub.tube) so that the at least one heater follows a mass remaining on a circular end region of the first and/or second portion while the glass tube is still rotating around the longitudinal axis (L.sub.tube).
2. The process of claim 1, wherein the at least one heater is at least one gas burner.
3. The process of claim 1, further comprising transporting the glass tube from one glass container processing station to a second glass processing station.
4. The process of claim 1, wherein the step of holding the glass tube in the first and second clamping chucks comprises holding the glass tube in a vertical position, wherein the step of separating the first and second portions from one another comprises pulling the first portion downwards along the longitudinal axis (L.sub.tube) and pulling the second portion upwards along the longitudinal axis (L.sub.tube), and wherein the step of moving the at least one heater comprises moving the at least one heater downwards so that the at least one heater follows an upper end of the first portion.
5. The process of claim 1, further comprising keeping a distance between the at least one heater and the circular end region constant while moving the at least one heater.
6. The process of claim 1, further comprising forming a final shape of the circular end region as a result of the heat from the at least one heater during the step of moving the at least one heater.
7. The process of claim 6, wherein the circular end region is not contacted during the step of forming the final shape.
8. The process of claim 6, further comprising equalizing a glass thickness of the circular end region.
9. The process of claim 8, wherein the step of equalizing the glass thickness further comprises maintaining the temperature above the glass transition temperature while the heated glass tube is still rotating around the longitudinal axis (L.sub.tube).
10. The process of claim 9, wherein the step of equalizing the glass thickness further comprises contacting the circular end region with a molding tool.
11. The process of claim 1, further comprising: heating, via a further heater, the first portion at an end opposite the circular end region to the temperature above the glass transition temperature while the glass tube is rotating around the longitudinal axis (L.sub.tube); and forming an orifice at the end opposite the circular end region.
12. A glass container, comprising: a glass tube having a first end and a second end, the tube having a glass thickness (d.sub.tube), an inner diameter (D.sub.tube), and a longitudinal axis (L.sub.tube) that passes through a centre of the first and second ends; and a circular glass bottom that closes the glass tube at the first end, wherein, for any cut surface of the circular glass bottom that is obtainable by cutting the circular glass bottom in a plane that includes the longitudinal axis (L.sub.tube), a condition d.sub.max/d.sub.tube×(d.sub.max/d.sub.min−1)≤1.1 is fulfilled, and wherein d.sub.max is a maximum glass thickness of the circular glass bottom and d.sub.min is a minimum glass thickness of the circular glass bottom as determined within a cut surface within a range from x=−0.5×D.sub.tube/2 to x=+0.5×D.sub.tube/2, wherein the centre is at a position x=0, and wherein d.sub.min and d.sub.max are both measured in a direction that is parallel to the longitudinal axis (L.sub.tube).
13. The glass container of claim 12, wherein the cut surface is within the range from x=−0.65×D.sub.tube/2 to x=+0.65×D.sub.tube/2.
14. The glass container of claim 12, wherein the cut surface is within the range from x=−0.75×D.sub.tube/2 to x=+0.75×D.sub.tube/2.
15. The glass container of claim 12, wherein the cut surface is within the range from x=−0.85×D.sub.tube/2 to x=+0.85×D.sub.tube/2.
16. The glass container of claim 12, wherein the condition that is fulfilled is d.sub.max/d.sub.tube×(d.sub.max/d.sub.min−1)≤0.9.
17. The glass container of claim 12, wherein the condition that is fulfilled is d.sub.max/d.sub.tube×(d.sub.max/d.sub.min−1)≤0.7.
18. The glass container of claim 12, wherein the condition that is fulfilled is d.sub.max/d.sub.tube×(d.sub.max/d.sub.min−1)≤0.5.
19. The glass container of claim 12, further comprising a glass mass (mg) and an interior volume (Vi), wherein a second condition is fulfilled that comprises m.sub.g/V.sub.i.sup.0.75<2.0
20. The glass container of claim 12, wherein the glass container is configured as a packaging container for a medical or a pharmaceutical product.
21. The glass container of claim 12, further comprising a medical or a pharmaceutical product in an interior of the glass container.
22. The glass container of claim 12, wherein the glass container comprises a glass selected from a group consisting of borosilicate glass, aluminosilicate glass, soda lime glass, fused silica, and any combinations thereof.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0071] FIG. 1 shows a glass processing machine 102 known from the prior art and also illustrates a process for the preparation of glass containers known from the prior art;
[0072] FIGS. 2A-D show the process for the preparation of a glass container 100 according to the present invention;
[0073] FIG. 3 shows the movement of the separation gas burners 110 and the lower clamping chucks 109 at the time at which the lower clamping chucks 109 are moved downwards;
[0074] FIG. 4 shows a side view of container 100 according to the present invention;
[0075] FIG. 5A shows in a side view the localization of plane 118 that is used to determine d.sub.max and d.sub.min in the circular glass bottom 112 of the glass container;
[0076] FIG. 5B shows the localization of d.sub.max and d.sub.min as well as the width of the area within which these values are to be determined in an exemplary bottom cross-section;
[0077] FIG. 6A shows the thickness of the glass in the circular glass bottom 112 of a glass container 100 prepared by a process known from the prior art across the whole breadth of the bottom;
[0078] FIG. 6B shows the thickness of the glass in the circular glass bottom 112 of a glass container 100 prepared by the process according to the present invention;
[0079] FIG. 7 shows a glass processing machine 102 according to the present invention and also illustrates the process according to the present invention;
[0080] FIG. 8 shows a particular embodiment of a glass processing machine 102 according to the present invention and also illustrates a particular embodiment of the process according to the present invention;
[0081] FIG. 9 shows a further particular embodiment of a glass processing machine 102 according to the present invention and also illustrates a further particular embodiment of the process according to the present invention;
[0082] FIG. 10 shows a further particular embodiment of a glass processing machine 102 according to the present invention and also illustrates a further particular embodiment of the process according to the present invention.
DETAILED DESCRIPTION
[0083] FIG. 1 shows a glass processing machine 102 known from the prior art and also illustrates a process for the preparation of glass containers known from the prior art. In such a machine both the tubes (part A: large wreath 114A) and the separated vials (part B: small wreath 114B) are held vertically in rotating chucks on two adjacent rotating rings 114A, 114B. This type of machine has the working positions (1 to 16: part A and 1 to 8: part B) arranged one after, between which the tubes and vials are transported by the wreaths in clocked fashion. Station 107a at the point that connects the two rings 114A, 114B corresponds to the separation station at which the glass tube is heated at a defined position by means of two separation gas burners 110 so far that it becomes deformable. As soon as this temperature is reached, the tube—under continuing rotation and heating by means of the burner 110—is extended in axial direction by means of a linear downwards movement of the lower chuck. Thereby the tube in the heated region extends under simultaneous tapering of its diameter, so that a constriction region in the form of a glass thread results. After the downward movement the constriction region is further heated. However, in the prior art process the separation gas burner remain at the same height when moving downwards the lower clamping chucks. After the lower portion of the glass tube has been finally separated, the glass is liquefied on positions 2 to 4 of the B-wreath 114B under massive input of heat at the upper edge of the of the lower portion of the glass tube in order to finally shape the bottom geometry.
[0084] FIGS. 2A-D show the process for the preparation of a glass container 100 according to the present invention as it can be performed, for example, at separation station 107a in glass processing machine shown in FIG. 1. In a first process step I) the glass tube 101 having an upper portion 105 with an upper end 106 and a lower portion 103 with a lower end 104 is held by means of upper and lower clamping chucks 108, 109 in a vertical position. The glass tube is heated at a defined position between the lower and the upper part 103, 105 by means of two opposed separation gas burners 110 to a temperature above the glass transition temperature while the glass tube 101 is rotating around its longitudinal axis L.sub.tube (see FIG. 2A). In process step II) the lower portion 103 of the glass tube 101 is pulled downwards by moving downwards the lower clamping chucks 109 while the glass tube 101 is rotating around its longitudinal axis L.sub.tube (see FIG. 2B). When moving downwards the lower clamping chucks 109 and thus also the lower portion 103 of the glass tube 101, a glass thread 111 is formed (see also FIG. 2B). When further moving downwards the lower portion 103, this portion is separated from the upper portion 105 by pulling apart the glass thread 111, the part of the mass of the glass thread 111 that remains at the lower portion 103 of the glass tube 101 forming a circular bottom 112 (see FIGS. 2C and 2D). The process according to the present invention is characterized in that, while pulling downwards the lower portion 103, the at least one separation gas burner 110 does not remain at the same position as it is observed in the process known from the prior art, but is moved downwards in a direction that is substantially parallel to the direction in which the lower clamping chucks 109 are moved downwards (indicated by the arrows beneath the separation gas burners 110 in FIG. 2A), the at least one separation gas burner 110 thereby following the upper end 113 of the lower portion 103.
[0085] FIG. 3 shows the movement of the separation gas burners 110 and the lower clamping chucks 109 at the time at which the lower clamping chucks 109 are moved downwards. In the embodiment of the process shown in FIG. 3, the lower clamping chucks 109 are moved downwards at a point of time t and the at least one separation gas burner 110 is moved downwards at a point of time t′=t+Δt, wherein Δt can be zero (which means that the lower clamping chucks 109 and the at least one separation gas burner 110 are moved downwards simultaneously) or Δt can be larger than zero. In this case the at least one separation gas burner 110 is moved downwards with a time delay in relation to the lower clamping chucks 109. As can also be seen in the embodiment of the process according to the present invention shown in FIG. 3, the at least one separation gas burner 110 is moved downwards starting from a position Y′.sub.0 to a position Y′.sub.stop and the lower clamping chucks 109 start from a position Y.sub.0 and, preferably after the at least one separation gas burner 110 has stopped at position Y′.sub.stop, to stop at a position Y.sub.stop, Y wherein |Y′.sub.stop−Y′.sub.0|<|Y.sub.stop−Y.sub.0|. According to this embodiment it is thus preferred that the distance with which the at least one separation gas burner 110 is moved downwards is smaller than the distance with which the lower clamping chucks 109 are moved downward.
[0086] FIG. 4 shows a side view of container 100 according to the present invention. The container 100 includes as a container part a glass body 115 in the form of a glass tube having a glass thickness d.sub.tube and an inner diameter D.sub.tube (which correspond to the thickness and the inner diameter of the glass tube 101 that has been used to prepare the container 100) with a first end 116 and a further end 117, the glass body 115 being characterized by a longitudinal axis L.sub.tube that passes through the centre of the first and the further end 116, 117. The glass container 100 further includes as a container part a circular glass bottom 112 that closes the glass body 115 at the first end 116. For any cut surface 118 of the circular glass bottom 112 that is obtainable by cutting the circular glass bottom 112 in a plane that includes the longitudinal axis L.sub.tube (see FIG. 5A) the following condition is fulfilled:
d.sub.max/d.sub.tube×(d.sub.max/d.sub.min−1)≤1.1
[0087] wherein d.sub.max corresponds to the maximum glass thickness of the circular glass bottom 112 and d.sub.min to the minimum glass thickness of the circular glass bottom 112 as determined within a given cut surface 118 within the range from x=−0.5×D.sub.tube/2 to x=+0.5×D.sub.tube/2, the centre of the circular glass bottom 112 being at position x=0, wherein and are both measured in a direction that is parallel to the longitudinal axis L.sub.tube.
[0088] FIG. 5A shows in a side view the localization of plane 118 that is used to determine d.sub.max and d.sub.min in the bottom 112 of the glass container. Plane 118 corresponds to the plane that is centrically located in the glass container 100 and that includes the longitudinal axis L.sub.tube of the glass container (indicated by the dashed line in FIG. 5A), i. e. the axis that goes perpendicular through the centre of the bottom 112 (see FIG. 5B).
[0089] FIG. 5B shows the localization of d.sub.max and d.sub.min as well as the width of the area within which these values are to be determined in an exemplary bottom cross-section. As can be seen, d.sub.max and d.sub.min are determined within an area the extends over 50% of the area of the circular glass bottom, wherein the centre of this area is located in the centre of the circular glass bottom 112.
[0090] FIG. 6A shows a profile of the thickness of the glass in the circular glass bottom 112 of a glass container 100 in millimeters (mm) prepared by a process known from the prior art across the whole breadth of the bottom in millimeters (mm) from the longitudinal axis L.sub.tube, which is indicated as 0 on the x-axis. Similarly, FIG. 6B shows a profile of the thickness of the glass in the circular glass bottom 112 of a glass container 100 in millimeters (mm) prepared by a process according to the present invention in which at least one separation gas burner 110 follows at least one portion of the glass tube in the separation process across the whole breadth of the bottom in millimeters (mm) from the longitudinal axis L.sub.tube, which is indicated as 0 on the x-axis.
[0091] As can be seen from comparing FIGS. 6A and 6B, by means of the process according to the present invention an advantageous bottom geometry of the glass container 100 can be obtained, compared to the bottom geometry obtained in a prior art process in which the separation gas burner 110 remain in a fixed position. The present invention thus enables the preparation of a new, unprecedented quality of the bottom geometry that is ideal for automated inspection processes, both unfilled and filled as the differences between the maximum and minimum value of the thickness of the glass bottom 112 (i. e. d.sub.max and d.sub.min) is significantly reduced (i. e. the thickness of the glass in the circular bottom 112 is significantly more uniform over the entire area of the circular bottom 112 compared to glass containers made by the state of the art process).
[0092] FIG. 7 shows a glass processing machine 102 according to the present invention and also illustrates the process according to the present invention. Although in this glass processing machine two separate wreaths 114A, 114B are provided, it would also be possible to perform the process according to the present invention in a glass processing machine that includes a single wreath 114 in which both, an orifice, preferably an orifice in the form of a flange or rolled rim, at one end of the container 100 and a circular bottom 112 at the other end of the container are formed. In the glass processing machine shown in FIG. 7 the final shape of the circular glass bottom 112 of the glass container 100 is formed at separation station 107a at which the lower and upper portion 103, 105 of the glass tube 101 are separated from each other and in which the separation gas burners 110 are moved downwards together with the lower clamping chucks 109 when tearing apart the glass thread 111. In the process and device shown in FIG. 7 no additional bottom shaping gas burners 119 or molding tools 120 are provided to further shape the circular glass bottom 112 of the glass containers. In such a process the outer surface of the upper end 113 of the lower portion 103 of the glass tube 101 (i. e. the end at which the circular glass bottom 112 is formed) does not come into contact with any part of the glass processing machine 103 while the final shape of the circular glass bottom 112 is formed.
[0093] FIG. 8 shows further a particular embodiment of a glass processing machine 102 according to the present invention and also illustrates a further particular embodiment of the process according to the present invention. Here, an additional bottom shaping gas burners 119 is provided at a further bottom shaping station 107b (in FIG. 8 this process station is located at wreath 114B, but it would also be possible to provide a single wreath 114 in which this additional bottom shaping station 107b is provided at a process station that immediately follows the separation station 107a) by means of with the final shape of the circular glass bottom 112 is further modified. The additional bottom shaping gas burner 119 is particularly useful to equalize the knots which, after the circular glass bottom has been formed at process station 107a by means of the process according to the present invention, are only slightly pronounced.
[0094] FIG. 9 shows a further particular embodiment of a glass processing machine 102 according to the present invention and also illustrates a further particular embodiment of the process according to the present invention. Here, a molding tool 120 is provided at a further bottom shaping station 107b (in FIG. 9 this process station is again located at wreath 114B, but—as in case of the additional process station including an additional bottom shaping gas burner 119 shown in FIG. 8—it would also be possible to provide a single wreath 114 in which also this additional bottom shaping station 107b is provided) by means of with the final shape of the circular glass bottom 112, particularly the final shape of the outer surface of the circular glass bottom 112, is further modified.
[0095] FIG. 10 shows a further particular embodiment of a glass processing machine 102 according to the present invention and also illustrates a further particular embodiment of the process according to the present invention. The approach shown in FIG. 10 is a combination of the approaches shown in FIGS. 8 and 9. The glass processing machine shown in FIG. 10 includes both, a further bottom shaping station 107b that includes an additional bottom shaping gas burner 119 as well as a further bottom shaping station 107b that includes a molding tool 120.
LIST OF REFERENCE NUMERALS
[0096] 100 glass container [0097] 101 glass tube [0098] 102 glass processing machine [0099] 103 first or lower portion of the glass tube 101 [0100] 104 first or lower end of the first or lower portion 103 [0101] 105 second or upper portion of the glass tube 101 [0102] 106 second or upper end of the second or upper portion 105 [0103] 107, 107a, 107b, 107c processing stations [0104] 108 first or upper clamping chucks [0105] 109 second or lower clamping chucks [0106] 110 separation gas burner [0107] 111 glass thread [0108] 112 circular bottom [0109] 113 upper end of portion 103, 105, preferably of lower portion 103 [0110] 114, 114A, 114B circle (or wreath) including processing stations 107 [0111] 115 glass body [0112] 116 first end of glass body 115 [0113] 117 further end of glass body 115 [0114] 118 cut surface [0115] 119 bottom shaping gas burner [0116] 120 molding tool
