Protecting mixed gas supplier for magnesium-alloy smelting furnace

Abstract

The invention comprises a gas-mixing unit, a gas-collecting unit and at least one gas supply unit for supplying gas into the smelter. The gas-mixing unit includes a SF6 gas pipeline, a nitrogen gas pipeline and a mixed gas pipeline. The SF6 gas pipeline and the nitrogen gas pipeline are connected with the gas inlet of the mixed gas pipeline. The gas outlet of the mixed gas pipeline is connected with the gas-collecting unit and the gas-collecting unit is connected with each gas supply unit through the mixed gas pipeline.

Description

【Technical field】 [0001] The invention relates to a protective gas mixing gas supply device for a magnesium alloy melting furnace. 【Background technique】 [0002] Due to the special chemical properties of magnesium, the molten magnesium on the surface of magnesium and magnesium alloys is very easy to oxidize and burn during the melting and casting process, so special gas protection measures are required. [0003] In the early days, magnesium alloy smelting mainly used salt covering flux for protection. Although this method has a good protection effect, it produces a large amount of slag, smoke and harmful gases, causing equipment corrosion and environmental pollution. What is more serious is that the covering flux impurities enter the magnesium alloy. Fluid, resulting in the decline of the mechanical properties of magnesium alloy products and the deterioration of corrosion resistance, thus restricting the development of magnesium alloy products; since the 1970s, the melting ...

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Problems solved by technology

At the same time, it is very difficult to realize the precise mixing of gases with a mixing ratio of 0.1 to 0.4%.

[0004] The existing protective gas mixing gas supply device applied to the protection of magnesium alloy furnaces is divided into two types: 1) a gas mixing device with a balance regulator used in the supporting gas mixing equipment of FRECH's die casting machine, and its mixing regulator is a patented product , the price is expensive, the structure is complex, the stability is poor, and it cannot be monitored in real time; 2) Another structure is to use two flowmeters to measure and control the flow of SF6 and nitrogen respectively, and its accuracy depends on the stability of the pressure and the flowmeter Accuracy, the Chinese patent No. ZL03239990.1, titled "On-Line Mixed Gas Supply Equipment for Magnesium Alloy Melting Protection", and the announcement date is March 17, 2004 adopts this technology to improve control accuracy Using mass flow controllers and computer monitoring measures, although the control accuracy can be improved in theory, the corrosiveness of SF6 will greatly reduce the service life of the flow sensor for the accuracy of the mass flow controller. In fact, no suitable method for SF6 gas can be found. In addition, the mass flow controller mentioned above is very expensive, difficult to maintain and calibrate, so it is not practical; in addition, due to the use of electronic control measures, in the event of a sudden power failure, the equipment cannot work normally, There are security risks

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