A furnace top feeding device of a semi-closed submerged arc furnace comprises a weighing stock bin, a finger valve, a hydraulic
gate valve, a herringbone feed tube, an inclined feed tube and a feed
nozzle. The weighing stock bin is fixed to a weighing stock bin floor, a lower opening of the weighing stock bin is connected with the finger valve and the hydraulic
gate valve, the herringbone feed tube is fixed to a feed tube mounting floor, an upper end opening of the herringbone feed tube is connected with a discharging
pipe of the hydraulic
gate valve, an upper end opening of the inclined feed tube is communicated with the a lower end opening of the herringbone feed tube, a lower end opening of the inclined feed tube is communicated with the feed
nozzle, a pneumatic
flap valve is arranged on the inclined feed tube, and the pneumatic
flap valve is in
interlocking and interaction with the hydraulic gate valve. The device has the advantages that weight changes of materials can be monitored by the weighing stock bin in real time, detection is continuous, safe and reliable, the weighing precision is reliable, quantitative feeding is achieved, the inclined feed tube is sealed by the materials, the
impact of the materials to the inclined feed tube is small, the service life of the inclined feed tube is prolonged, the occupied space of the pneumatic
flap valve is small, and the original arrangement of the factory is not affected.