Vacuum automatic feeding device

The utility model relates to a vacuum automatic feeding device, which is arranged at an inlet of a reactor and is characterized by comprising a totally-enclosed feeding hopper mechanism and an automatic adjusting valve mechanism, wherein the totally-enclosed feeding hopper mechanism comprises a feeding hopper and a sealing cover which are fixedly connected by bolts; the automatic adjusting valve mechanism comprises a valve body, a valve rod, a valve core, a bellows, an elastic part, a fixing frame, a pressure guide pipe and an executing mechanism; the elastic part comprises a fixed plate and a spring; and a diaphragm plate divides the executing mechanism into a high pressure bin and a low pressure bin. The vacuum automatic feeding device has the advantages of convenient disassembly and assembly of main equipment, easy replacement of accessories, convenient use and long service life.