Closed feeding device

The utility model relates to the technical field of feeding devices, and discloses a closed feeding device which comprises a hopper, a valve, a cover plate, a three-way connector, a mounting plate, a telescopic air cylinder, a chock plug, a vacuum pump and a closing valve. When raw materials need to be added, the closing valve is closed firstly, then the telescopic air cylinder is matched with the chock plug to push the remaining raw materials into the material conveying section of the three-way connector, the chock plug can be matched with the material conveying section of the three-way connector to seal the lower side of the material conveying section, then the hopper is opened, the raw materials are added and then closed, and then the interior of the hopper is vacuumized through the vacuum pump. And then the telescopic cylinder drives the chock plug to return, and then the closing valve is opened. By the adoption of the structure, the vacuum environment in the hopper can be kept, and air in the hopper is p