Vacuum suction casting chamber nitrogen charging explosion-proof device

Abstract

The invention discloses a vacuum suction casting chamber nitrogen charging explosion-proof device. The vacuum suction casting chamber nitrogen charging explosion-proof device comprises a suction casting chamber, an electromagnetic pressure relief valve and a nitrogen container. A shell type casting mold and a ceramic riser tube are mounted in the suction casting chamber. The top of the suction casting chamber is provided with the electromagnetic pressure relief valve. The electromagnetic pressure relief valve is connected with the nitrogen container through a hose. Nitrogen is introduced intothe suction casting chamber to conduct pressure relief after completion of suction casting. The nitrogen container is provided with a pressure reducing valve, a pressure meter and a stop valve to monitor the device state. Through the vacuum suction casting chamber nitrogen charging explosion-proof device, nitrogen is introduced into the vacuum suction casting chamber for protection during suctioncasting and pressure relief to inhibit oxidation reaction of combustible gas generated from the shell type casting mold. A blast accident caused due to the fact that violent oxidation reaction and gasexpansion occur to oxygen and combustible gas after air admission is prevented. Personal security during operation is effectively protected.

Description

technical field [0001] The invention belongs to the field of explosion-proof devices, in particular to a nitrogen-filled explosion-proof device for a vacuum suction casting chamber. Background technique [0002] The vacuum suction casting process is to place the mold in a sealed suction casting chamber, immerse the lower end of the ceramic liquid riser into the liquid metal, and then evacuate the suction casting chamber to make the molten metal fill the mold from bottom to top under negative pressure. And the forming method of feeding, solidification and cooling under negative pressure. After the pressure holding and solidification is completed, the pressure is released, and the molten metal in the ceramic liquid riser flows back into the crucible molten pool. [0003] We use the vacuum suction casting process to produce heat-resistant steel products for automotive turbochargers. The melting and pouring temperature of metal alloys is high. Generally, the temperature of the ...

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Problems solved by technology

[0005] Due to the heavy weight of the suction casting shell mold, the large amount of gas generated by the coated sand, the fast gas generation speed, and the high suction casting temperature of the heat-resistant steel turbine shell, a large amount of air enters the suction casting chamber instantaneously when the suction casting pressure is released, and the hot The flammable gas produced by the shell mold and the oxygen in the air undergo a violent oxidation reaction, and the gas expands instantaneously. Although there is an electromagnetic pressure relief valve to exhaust the pressure, the gas generation speed of the shell mold coated sand is much faster than the exhaust speed. As a result, an explosion phenomenon occurs, causing personal injury safety accidents during the operation

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