Multi-nozzle tubular plasma deposition burner for producing preforms as semi-finished products for optical fibers

Abstract

The invention relates to a multi-nozzle, tubular plasma deposition burner ( 1 ) for producing preforms as semi-finished products for optical fibers, wherein a media stream containing glass starting material and a carrier gas is fed to the burner ( 1 ), means for feeding at least one dopant using at least one precursor gas and a substantially perpendicular orientation of the burner gas longitudinal axis relative to the center axis of the substrate ( 4 ). According to the invention, a first partial stream of a first gas or gas mixture, in particular a precursor gas, is fed to the plasma and to the substrate ( 4 ) by way of at least one nozzle running in the burner longitudinal axis and a second partial stream of the first gas or of another gas or gas mixture, in particular a precursor gas, is fed to the plasma and the substrate by way of another nozzle ( 5 ); said gases or gas mixtures are fed in such a way that said partial streams combine in the vicinity of the substrate.

1 . Multi-nozzle, tubular plasma deposition burner for producing preforms as semi-finished products for optical fibers, wherein a media stream containing glass starting material and a carrier gas is fed to the burner, means for feeding at least one dopant using at least one precursor gas and a substantially perpendicular orientation of the longitudinal axis of the burner relative to the center axis of the substrate,
 wherein   a first partial stream of a first gas or gas mixture, in particular a precursor gas, is fed to the plasma and to the substrate by way of at least one nozzle running in the longitudinal axis of the burner and a second partial stream of the first or of another gas or gas mixture, in particular a precursor gas, is fed to the plasma and to the substrate by way of another nozzle in such a way that said partial streams merge in the vicinity of the substrate.   
     
     
         2 . Burner according to  claim 1 ,
 wherein   the other nozzle is provided as multi-nozzle or nozzle pair, comprising two or more individual nozzles arranged offset relative to the longitudinal axis of the burner.   
     
     
         3 . Burner according to  claim 1 ,
 wherein   the other nozzle or the nozzles of the nozzle pair are arranged at an angle deviating from the longitudinal axis of the burner.   
     
     
         4 . Burner according to  claim 2 ,
 wherein   the nozzle pair comprises a group of individual nozzles as a nozzle chain, wherein the nozzle chains of the nozzle pairs are arranged opposite of each other at a specified angle.   
     
     
         5 . Burner according to  claim 2 ,
 wherein   the angular position of the individual nozzles or the nozzle chains of the nozzle pairs is adjustable.   
     
     
         6 . Burner according to  claim 1 ,
 wherein   the other nozzle or the nozzle pair is provided outside the burner, at a distance relative to the burner tube closest to the substrate, in the space between the substrate surface and the burner.   
     
     
         7 . Burner according to  claim 1 ,
 wherein   the other nozzle or at least one of the nozzle chains is provided, which create a tangential gas stream component relative to the tube configuration of the burner.   
     
     
         8 . Burner according to  claim 1 ,
 wherein   the other nozzle, the nozzle pair or the respective nozzle chain is mobile and adjustable.   
     
     
         9 . Burner according to  claim 1 ,
 wherein   the nozzle running in the longitudinal axis of the burner comprises two interlocked tubes with thick walls.   
     
     
         10 . Burner according to  claim 9 ,
 wherein   the tubes are positioned inside each other concentrically or deviating from the concentric arrangement, wherein the wall thickness of the tubes ranges between ≧2 mm to essentially 20 mM.   
     
     
         11 . Burner according to  claim 9 ,
 wherein   the inside of the tube assembly has a greater distance from the plasma space than the outer tube of the tube assembly.   
     
     
         12 . Burner according to  claim 1 ,
 wherein   the at least one precursor gas feed comprises a chamber for mixing and/or calming the gas stream.   
     
     
         13 . Burner according to  claim 1 ,
 wherein   the nozzle chains comprise a plate shape and a plurality of nozzle bore holes.   
     
     
         14 . Burner according to  claim 1 ,
 wherein   the burner tube assembly is surrounded by a protective gas, in particular a nitrogen curtain.   
     
     
         15 . Burner according to  claim 1 ,
 wherein   the nozzle running in the longitudinal axis of the burner is designed as a nozzle group for partial streams converging in the plasma.   
     
     
         16 . Burner according to  claim 15 ,
 wherein   the nozzle group comprises individual nozzles with different or modifiable nozzle cross sections or cross-sectional areas.   
     
     
         17 . Burner according to  claim 1 ,
 wherein   the other nozzle or the individual nozzles of the nozzle chain are designed as a slotted nozzle.   
     
     
         18 . Burner according to  claim 1 ,
 wherein   the other nozzle or the individual nozzles of the nozzle chain are designed as concentric nozzles with jet-forming properties.   
     
     
         19 . Burner according to  claim 4 ,
 wherein   the nozzle chain is designed as a multi-line nozzle chain with nozzles arranged on top of each other or offset opposite from each other.   
     
     
         20 . Burner according to  claim 7 ,
 wherein   the tangential gas component runs in the rotational direction of the plasma helix.   
     
     
         21 . Burner according to  claim 8 ,
 wherein   the other nozzle, the nozzle pair or the respective nozzle chain is adjustable toward the direction of the substrate motion.   
     
     
         22 . Burner according to  claim 12 ,
 wherein   the chamber is designed as a prechamber at the end of the burner away from the substrate, running in the longitudinal direction of the burner with the gas feed arranged on the side.   
     
     
         23 . (canceled)