Metering tank for continuously dropwise adding chemical supplementary materials

The utility model discloses a metering tank for continuously dropwise adding chemical supplementary materials, which comprises a metering tank, a feed port and an air inlet are respectively arranged above two side wall surfaces of the metering tank, and a feed pipe and an air inlet pipe are respectively connected in the feed port and the air inlet by penetrating through the wall surfaces of the metering tank to the inside of the metering tank. A feeding pipe seal is arranged on the portion, exposed out of the outer end of the metering tank, of the feeding pipe in a rotating mode, an air inlet pipe seal is arranged on the portion, exposed out of the outer end of the metering tank, of the air inlet pipe in a rotating mode, a discharging port is formed in the bottom of the metering tank, and a one-way plug is arranged in the discharging port. When the device is used, a certain amount of gas is filled into the metering tank, so that air pressure is generated in the metering tank to push materials to be discharged