EP0216739A2
Expired / Lapsed
EP
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A method and an apparatus for heating glass tubes
Assignee: KTH Royal Institute of Technology
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Filing: 1986-09-19
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Granted: —
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Expires: 2006-09-19
Abstract
Abstract A method of heating glass tubes, particularly quartz tubes for the manufacture of optical fibres, where the tube is pre-heated, preferably by means of a gas flame, whereafter the tube is heated by means of microwave energy generated by a microwave generator (1), by introducing the tube axially into a microwave cavity (3) comprising in its end walls (6,7) or end surfaces openings for the tube. According to the invention, at least one electrical field is given a field image according to a TM-0n0-mode, preferably according to the TM-020-mode, which mode has a maxima (10) along the central axis (9;c-c) of the cavity (3) and a minima (11,12) on each side of the radially spaced from the central axis (9;c-c), where the electrical field portion located between said minima (11,12) is used for heating the wall of said glass tube (8). According to a preferred embodiment, an additional electrical field is caused to be formed by means of a second microwave generator (15), which field is given a field image according to a TE-01n-mode, preferably according to the mode TE-011, which field therewith is superposed upon the field according to the TM-0n0-mode.
Inventors
- 👤 Yngve Hässler
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 07:20
CPC Classifications
C; C03; C03B; C03B23/00; C03B23/04; C03B23/043; C03B37/00; C03B37/01; C03B37/012; C03B37/014; C03B37/018; C03B37/01807; C03B37/01815; C03B37/01876
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
139 words
A method of heating glass tubes, particularly quartz tubes for the manufacture of optical fibres, by pre-heating the tube, preferably by means of a gas flame, whereafter the tube is heated by means of microwave energy generated by a microwave generator (1), by introducing the tube axially into a microwave cavity (3) comprising in its end walls (6,7) or end surfaces openings for the tube, characterized in that at least one electrical field is given a field image according to a TM-0n0-mode, preferably according to the TM-020-mode, which mode has a maxima (10) along the central axis (9;c-c) of the cavity and a minima (11,12) on each side of and radially spaced from the central axis (9;c-c), and that the electrical field portion located between said minima (11,12) is utilized for heating the wall of said glass tube (8).
Claim 2
Independent Claim
139 words
A method of heating glass tubes, particularly quartz tubes for the manufacture of optical fibres, by pre-heating the tube, preferably by means of a gas flame, whereafter the tube is heated by means of microwave energy generated by a microwave generator (1), by introducing the tube axially into a microwave cavity (3) comprising in its end walls (6,7) or end surfaces openings for the tube, characterized in that at least one electrical field is given a field image according to a TM-0n0-mode, preferably according to the TM-020-mode, which mode has a maxima (10) along the central axis (9;c-c) of the cavity and a minima (11,12) on each side of and radially spaced from the central axis (9;c-c), and that the electrical field portion located between said minima (11,12) is utilized for heating the wall of said glass tube (8).
Claim 3
Dependent Claim
56 words
A method as defined in claim 1, characterized in that an additional electrical field is caused to be formed by means of a second microwave generator (15), which field is given a field image according to a TE-01n-mode, preferably according to the mode TE-011, which field therewith is superposed upon the field according to the TM-0n0-mode.
Claim 4
Dependent Claim
85 words
A method as defined in claim 2, characterized in that at least said firstmentioned microwave generator (1) is caused to generate said electrical fields during a deposition and, respectively, sintering phase, where layers with different substances are applied on the inside of the glass tube, and that during a subsequent collapsing phase, where the tube is to be collapsed to a rod, the said two microwave generators (1;15) are caused to generate each its respective electrical field according to the modes TM-0n0 and, respectively TE-01n.
Claim 5
Dependent Claim
37 words
A method as defined in claim 1,2 or 3, characterized in that a microwave cavity (3) of metal is used, which is axial-symmetrical in respect of an axis (9) extending through the centre of said openings (4,5).
Claim 6
Independent Claim
147 words
An apparatus for heating glass tubes, particularly quartz tubes for the manufacture of optical fibres,which apparatus comprises means for pre-heating the glass tube, preferably a gas flame, and comprises a microwave generator connected to a microwave cavity, which is provided with openings in its end walls or end surfaces for passing a glass tube through the cavity, characterized in that at least one microwave generator (1) via a wave guide (2) is connected to the cavity (3), so that at least one electrical field is given a field image according to a TM-0n0-mode, preferably according to the TM-020-mode, which mode has a maxima (10) along the central axis (9;c-c) of the cavity (3) and a minima (11,12) on each side of and radially spaced from the central axis (9;c-c), and that a longitudinal axis through the centre of said openings (4,5) coincides with said central axis (9).
Claim 7
Independent Claim
147 words
An apparatus for heating glass tubes, particularly quartz tubes for the manufacture of optical fibres,which apparatus comprises means for pre-heating the glass tube, preferably a gas flame, and comprises a microwave generator connected to a microwave cavity, which is provided with openings in its end walls or end surfaces for passing a glass tube through the cavity, characterized in that at least one microwave generator (1) via a wave guide (2) is connected to the cavity (3), so that at least one electrical field is given a field image according to a TM-0n0-mode, preferably according to the TM-020-mode, which mode has a maxima (10) along the central axis (9;c-c) of the cavity (3) and a minima (11,12) on each side of and radially spaced from the central axis (9;c-c), and that a longitudinal axis through the centre of said openings (4,5) coincides with said central axis (9).
Claim 8
Dependent Claim
54 words
An apparatus as defined in claim 5, characterized in that a second additional microwave generator (15) is connected to the cavity (3) so that an electrical field is given a field image according to a TE-01n-mode, preferably according to the mode TE-011, which field therewith is superposed upon the field according to the TM-0n0-mode.
Claim 9
Dependent Claim
28 words
An apparatus as defined in claim 6, characterized in that a control device (17) is capable to connect and disconnect each of the said two microwave generators (1,15).
Claim 10
Dependent Claim
29 words
An apparatus as defined in claim 5,6 or 7, characterized in that t he microwave cavity (3) is of metal and axial-symmetrical in respect of said central axis (9).
References Cited (Backward Citations)
No citation records indexed.
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