Automatic anti-suck-back nitrogen supplementing device capable of automatically alarming and protecting

The utility model discloses an automatic anti-suck-back nitrogen supplement device capable of automatic alarm protection, the front end and the rear end of a compressor are respectively provided with a first pipe and a third pipe, a ventilation column is arranged in a mounting groove and located at the top end of the third pipe, the bottom end of a shell is provided with an air inlet in a penetrating manner, the air inlet is communicated with the first pipe, and the air inlet is communicated with the second pipe. A ventilation groove is formed in the ventilation column, an air door column is arranged in the ventilation groove, an air guide groove is formed in the air door column in a penetrating mode, an air needle is arranged in the air guide groove, and the position, located on the outer wall of the air needle, of the top end of the air door column is sleeved with an air sealing ring. The gas exchange column is arranged, suck-back is prevented when gas is not supplemented under the action of the gas needle