| 摘要 |
A Microwave cavity for the heating of thick-walled glass tubes, especially quartz tubes, for the production of optical fibres, which cavity is designed to be fed with microwave energy from a microwave generator, which cavity contains a hole in the centre for the insertion of a pipe in the cavity's opposite side exterior surfaces or end surfaces where the microwave generator is, via a wave guide, coupled to the cavity so that the strength of the electrical field only comes to include a tangential component (c) of a TE - 01n type, preferably the TE 011 type whereby the electric field comes to be so constructed that it is tangential with a tube's surfaces and so constructed that the strength of the electric field is nil alongside the cavity's surfaces. A feature of the invention is that the cavity (2') via a notch through its longitudinal axis (24) and running through the aforementioned holes (3', 4') has a constriction (23) in its centre part so that the radial distance from the cavity's geometric centre (25) to the cavity's (2') wall is less at the constriction (23) than at the same sides of the constriction<IMAGE> |
