External circulation vacuum sintering furnace for sintering neodymium iron boron

The utility model relates to an external circulation vacuum sintering furnace for sintering neodymium iron boron. The utility model relates to the technical field of magnetic material smelting. The device comprises a first vacuum pipe connected with a sintering furnace, a second vacuum pipe connected with a vacuum pump and a filter, a fixing pipe and a sealing ring are further included. The filtercomprises a filter pipe connected between the first vacuum pipe and the second vacuum pipe and a filter element arranged in the filter pipe; mounting ring grooves for mounting the sealing rings are formed in the two ends of the filtering pipe; the fixed pipe sleeves and abuts against the outer side of the filter pipe, and the two sides of the fixed pipe extend towards the first vacuum pipe and the second vacuum pipe and abut against the first vacuum pipe and the second vacuum pipe; and a limiting block is integrally arranged on the inner wall of the fixed pipe in the extending direction of the fixed pipe, and sliding