Method of producing glass vials
A method for producing glass vials, in particular pharmaceutical vials or pharmaceutical ampoules, from a glass tube is provided, the method including the following steps: (a) rotating the glass tube about a longitudinal axis thereof; (b) locally heating the glass tube from one side by means of at least one burner to at least the softening temperature of the glass; (c) reducing the diameter by pressing at least one forming body laterally against the heated region; and (d) separating the glass tube by means of a burner. A glass vial produced in such a way releases a reduced amount of alkali in accordance with ISO 4802 and has a decreased delamination tendency. Furthermore, in the hot-formed peripheral region, the alkali content is only slightly reduced when compared with the alkali content in the glass interior.
1. A method of producing glass pharmaceutical vials and pharmaceutical ampoules, from a glass tube, comprising the steps of:
(a1) providing said glass tube made of a glass having a certain softening temperature;
(a) rotating said glass tube about a longitudinal axis thereof at a rotating speed of 200 min −1 to 500 min −1 ;
(b) local heating of said glass tube by a burner from at least one side to said certain softening temperature of said glass to form a heated region;
(c) reducing a diameter of said glass tube by pressing at least one forming part laterally against said heated region to form a constricted region; and
(d) separating of said glass tube at said constricted region only by said burner so that two parts having a closed bottom are generated and so that said two parts have a sodium release according to ISO 4802-2 that is smaller than 0.5 μg/cm 2 .
2. The method of claim 1 , wherein after said step (b) an additional step (b1) is performed, wherein an extending of said glass tube in axial direction is performed for generating said constriction region.
3. The method of claim 1 , wherein said steps (a) to (d) are performed one after another in the given sequence while said glass tube is rotating.
4. The method of claim 1 , wherein said closed bottom of at least one of said two parts after said separating step (d) is pierced at its closed end by another burner.
5. The method of claim 1 , wherein said glass tube after step (a) is initially heated at one end and formed for generating a neck region of the vial to be formed, and subsequently is heated in a predetermined distance from said one end according to step (b).
6. The method of claim 1 , wherein said glass tube is driven at a rotating speed of 250 min −1 to 450 min −1 .
7. The method of claim 1 , wherein said glass tube is driven at a rotating speed of 300 min −1 to 400 min −1 .
8. The method of claim 1 , wherein said at least one forming part comprises a material selected from the group consisting of a tungsten alloy, an electro-graphite and a heat-resistant steel.
9. The method of claim 1 , wherein said at least one forming part is driven rotatingly.
10. The method of claim 1 , wherein said at least one forming part is heated.
11. The method of claim 1 , wherein said at least one forming part tapers towards said glass tube.
12. The method of claim 11 , wherein said at least one forming part is pointed.
13. The method of claim 1 , wherein pressing said at least one forming part comprises advancing a forming body from both sides of said glass tube.
14. A method of producing glass pharmaceutical vials and pharmaceutical ampoules, from a glass tube, comprising the steps of:
providing a glass tube made of a glass having a certain softening temperature;
rotating said glass tube about a longitudinal axis thereof;
locally heating said glass tube from at least one side to said certain softening temperature to form a locally heated region;
pressing at least one forming part laterally against said locally heated region to reduce a diameter of said glass tube until only a glass connection of reduced diameter between upper and lower tube sections remains; and
melting off, using a heater, said glass connection of reduced diameter so that two parts having a closed bottom are generated at said glass connection of reduced diameter using only said heater and so that an alkali content at an outer surface in the locally heated region is reduced up to at most 30% when compared with the alkali content at an inner surface.
15. The method of claim 14 , further comprising, prior to said pressing step, extending of said glass tube in an axial direction to form a constriction in said heated region.
16. The method of claim 14 , further comprising, prior to said melting off step, moving the at least one forming part out of contact with said glass tube.
17. The method of producing glass pharmaceutical vials and pharmaceutical ampoules, from a glass tube, comprising the steps of:
rotating a glass tube about a longitudinal axis thereof while locally heating said glass tube to form a locally heated region;
reducing a diameter of said locally heated region until a glass connection of reduced diameter between upper and lower tube sections remains; and
melting off, using a heater, said glass connection of reduced diameter so that two parts having a closed bottom are generated at said glass connection of reduced diameter using only said heater and so that said two parts have a sodium release according to ISO 4802-2 that is smaller than 0.5 μg/cm 2 .