Abstract: A burner for a vapour deposition process has a central nozzle for ejecting a glass precursor material, at least a crown of nozzles surrounding said central nozzle for ejecting a flame reactant, and a circular nozzle between said central nozzle and said crown of nozzles for ejecting an innershield gas, wherein the central nozzle has a concave shape in a cross section in the axial plane and, preferably, a symmetry about an axial plane.

Abstract: A burner for a vapor deposition process has a cylindrical central gas passage and a plurality of external gas passages surrounding the central gas passage. The burner has a back block defining an initial section of the gas passages, a face block defining a final section of the gas passages and a manifold plate positioned between the back block and the face block and defining an intermediate section of the external gas passages; the face block, the manifold plate and the back block have inner integral walls that define respective sections of the central gas passage.

Abstract: An apparatus for measuring the weight of a preform for optical fibers during a chemical deposition process for the formation of a preform is disclosed. The apparatus has at least one elastic constraint associated with at least one end portion of an elongated element made of a chemical deposition substrate for the formation of the preform, a device for inducing an oscillation, for example axial, on said elongated element, a device for detecting the frequency of oscillation of said elongated element, and a device for calculating the weight of the preform according to the detected frequency of oscillation. Advantageously, the device allows the realisation of a method for measuring the weight of the preform wherein the errors in measurement caused by thermal drift effects, by the axial distribution of the masses on the preform and by loads which are different from the mass of the preform in formation are reduced to below the required precision in measurement.

Abstract: An apparatus for measuring the weight of a preform for optical fibres during a chemical deposition process for the formation of a preform is disclosed. The apparatus has at least one elastic constraint associated with at least one end portion of an elongated element made of a chemical deposition substrate for the formation of the preform, a device for inducing an oscillation, for example axial, on said elongated element, a device for detecting the frequency of oscillation of said elongated element, and a device for calculating the weight of the preform according to the detected frequency of oscillation. Advantageously, the device allows the realisation of a method for measuring the weight of the preform wherein the errors in measurement caused by thermal drift effects, by the axial distribution of the masses on the preform and by loads which are different from the mass of the preform in formation are reduced to below the required precision in measurement.

Abstract: A burner for a vapour deposition process has a central nozzle for ejecting a glass precursor material, at least a crown of nozzles surrounding said central nozzle for ejecting a flame reactant, and a circular nozzle between said central nozzle and said crown of nozzles for ejecting an innershield gas, wherein the central nozzle has a concave shape in a cross section in the axial plane and, preferably, a symmetry about an axial plane.

Abstract: A burner for a vapour deposition process has a cylindrical central gas passage and a plurality of external gas passages surrounding the central gas passage. The burner has a back block defining an initial section of the gas passages, a face block defining a final section of the gas passages and a manifold plate positioned between the back block and the face block and defining an intermediate section of the external gas passages; the face block, the manifold plate and the back block have inner integral walls that define respective sections of the central gas passage.