Spraying gun with multiple flow passages

Abstract

A multi-channel spray gun for preparing optical fibres from prefabricated porous glass is composed of base, channel tube, and a group of the barrels with airflow inlet and nozzle around said channel tube. The said channel tube and barrels are coaxially installed to base. The said nozzle has a group of ring posts positioned coaxially on the tops of barrels. The airflow channels are formed between external wall of channel tube and internal wall of barrel, between the internal and external walls of adjacent barrels, between external wall of channel tube and the internal wall of ring post, and between the internal and external wall of ring posts. Its advantage is easy cleaning and exhange of parts.

Description

【Technical field】 [0001] The invention relates to a spray gun, in particular to a spray gun with a plurality of air flow passages. It can be used especially in devices for manufacturing optical fiber porous glass preforms by vapor deposition. 【Background technique】 [0002] At present, inorganic optical fibers have been widely used in the communication industry. Among them, quartz series optical fibers have become the main body of inorganic optical fibers because of their low optical loss, wide range of applicable light waves, and adaptability to long-distance communication. In the method of manufacturing quartz series optical fiber preforms, there is a vapor deposition method. When manufacturing optical fiber porous glass preforms, raw material gas, combustible gas, combustion-supporting gas and auxiliary gas are passed into the spray gun at a certain pressure, and ignited in the reaction chamber to generate hydrogen. Oxygen flame, so that hydrogen and oxygen hydrolysis re...

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Problems solved by technology

Therefore, the spray gun used must be a multi-tube structure, which includes a base, a flow pipe, a set of cylinders with air inlets and nozzles located around the flow pipe, where the flow pipe and the cylinder are coaxially installed on the base The upper nozzle and the nozzle include a group of ring columns located at the top of each cylinder, the ring columns are the extension of the cylinder, and the outer wall of the flow channel pipe and the inner wall of the cylinder, between the inner and outer walls of adjacent cylinders, and the inner wall of the flow channel tube Between the outer wall and the inner wall of the ring column of the nozzle, and between the inner and outer walls of each ring column of the nozzle, there are annular cavities that can form airflow channels. Its disadvantages are: 1) Because the ring column of the nozzle is consolidated with the cylinder, the cylinder The body and the cylinder are also consolidated on the base, so it is a non-detachable integral structure. It is difficult to clean its annular cavity after use, so the impurities in the airflow channel cannot be completely removed. , resulting in unremoved particles adhering to the surface of the porous glass preform, thus generating air bubbles when sintering into a transparent glass preform, seriously affecting product quality; The preform is prone to cracking, so it can only be used in the production device for depositing smaller fiber porous glass preforms with a diameter of less than 150mm; 3) Its integral structure will be scrapped as a whole due to local wear and tear , so its service life is short, and the cost of production is increased; 4) the existing integral spray gun is more troublesome to manufacture, so the cost of its own manufacture is also relatively high

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