VAD prepared large-core optical fiber parent metal blast burner

Abstract

The invention relates to a VAD prepared large-core optical fiber parent metal blast burner which comprises a cylindrical blast burner body, wherein a central feeding hole and a plurality of layers ofannularly-distributed air holes around the central feeding holes are formed in the peripheral direction of the blast burner body. The blast burner is characterized in that the plurality of layers of the annularly-distributed air holes sequentially include inner-layer separation air holes, inner-layer flame air holes, outer-layer separation air holes and outer-layer frame air holes from inside to outside; the inner-layer flame air holes include inner-layer flame oxygen holes and inner-layer flame hydrogen holes; the outer-layer flame air holes include outer-layer flame oxygen holes and outer-layer frame hydrogen holes. When the blast burner disclosed by the invention is utilized, a contact area between the raw materials and inner-layer gas can be enlarged through distribution of relative positions of all the gas pipelines and flow velocity matching among gas of all the pipelines; thus, combustion can be fuller, the purpose of manufacturing large-core optical fiber parent metal is achieved, and a production efficiency is improved.

Description

technical field [0001] The invention relates to a blowtorch for preparing a large-core-diameter optical fiber base material by VAD, and belongs to the technical field of optical fiber base material manufacturing. Background technique [0002] In the manufacture of VAD (external vapor deposition method) optical fiber base material, the raw material is hydrolyzed with the hydrogen-oxygen flame to generate a reaction product that can be used for deposition, and then the product accumulates layer by layer, and the powder rod becomes thicker. The powder stick gradually becomes longer. In reactive deposition, the torch plays an important role as a medium for transporting raw materials and gases, directly affecting the growth of the powder rod and the deposition quality. [0003] The linear velocity V of the innermost flame flow of the dual flame blowtorch designed in the patent CN100412015C in terms of flow rate ratio i and the flow rate V of the raw gas m Satisfy V i <V m...

AI Technical Summary

Problems solved by technology

[0003] The linear velocity V of the innermost flame flow of the dual flame blowtorch designed in the patent CN100412015C in terms of flow rate ratio i and the flow rate V of the raw gas m Satisfy V i m i , and it adopts the internal flame retraction stroke L to prevent the internal flame from spreading and increase the limited flame length; this method firstly has a flow rate of the raw material gas higher than the internal flame flow rate in terms of flow rate ratio, and the hydrolysis reaction of the particles needs a period of time, and Its faster speed to reach the deposition surface is not conducive to the full growth of the reacted particles. Secondly, the flow rate of the outer flame is related to the overall flame envelopment, and the flow rate is not described in detail; and the inner flame of the patent is retracted. It cannot solve the flame head dispersion effect of the flame before reaching the deposition

In the patent CN10838103B, the designed gas flow rate V1 for the center gas nozzle, and the gas flow rate of the small-diameter gas nozzle, flammable gas nozzle, and flammable gas nozzle from the inside to the outside are V2, V3, and V4 in order to satisfy: V1>V2>V3 >V4, which also adopts the fast flow ratio method of the central raw material. Due to the high speed of the central raw material, the outer gas cannot effectively wrap it, which will cause the loss of raw materials and affect the deposition efficiency.

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