The device is connected with the furnace head through the flange head, and uses the sleeve and the protective cover to form a nitrogen protection space structure. The nitrogen is sent into the protection device from the air inlet, which can prevent the casting pipe from being directly exposed to the air and being oxidized in the, so as to realize the gas protection effect on the casting pipe and the mold of the casting machine. In the casting process, by controlling the furnace head to turn down, the contact surface between the protective cover and the mold is controlled to fit and form a closed cavity structure, and then nitrogen is filled in to make full use of the penetration ability of nitrogen to protect the casting pipe; in the casting process, the liquid level in the furnace will continue to drop, so the casting liquid can flow out smoothly by controlling the bottom swing of the furnace head When the sleeve slides down in the adjusting cylinder, the spring will be compressed to adapt to the new casting position. At the same time, the upper end cover keeps relative rotation with the convex spherical surface and the adjusting cylinder, so as to adapt to the change of casting angle, and During the casting process, the contact surface between the protective cover and the mold can be kept close to prevent nitrogen leakage; after the casting, the furnace head is controlled to rise to make the spring automatically return to the initial state, and nitrogen is respectively filled into the protective cover and the cavity from the first air inlet.
In consideration of the need to remove water through the cold dryer before filling nitrogen, the temperature of nitrogen will drop. If the low-temperature nitrogen is directly filled into the cavity, the liquid copper will be instantly supercooled and the ingot quality will be weakened. Therefore, the nitrogen is heated from the upper part of the cover to the lower part of the cover, and then the liquid is heated from the lower part of the cover. In the whole casting process, the protective cover is always filled with nitrogen, which can effectively isolate the oxidation of oxygen on the liquid copper and the casting pipe, and protect the liquid copper and the casting pipe. In addition, the operator can observe the change of liquid copper in the device through the glass window during the casting process, so as to adjust the liquid level in time and realize the effective protection of the production process.