Composite feeding device

The utility model relates to a composite feeding device. The composite feeding device comprises a feeding bin, a bin cover, an emptying valve, a feeding part, a gas replacement part and a sight glass, the feeding bin is provided with a feeding port, a discharging port and a discharging port. The bin cover is movably connected with the feeding hole; the emptying valve is connected with the discharge port; the feeding part is mounted between the outer wall of the reaction kettle and the discharge hole of the feeding bin; wherein when the emptying valve is configured to be in an open state, the feeding part is configured to keep the feeding bin and the reaction kettle in an on-off state; when the emptying valve is configured to be in a closed state, the feeding part is configured to keep the charging bin and the reaction kettle in a communication state; the gas replacement part is communicated with the feeding bin; when the feeding bin and the reaction kettle are in an on-off state, the gas replacement part is c