Split type over-frame dual-layer joint

The utility model belongs to the technical field of a connecting piece, relating to a split type over-frame dual-layer joint that is used for connecting aircraft fuel ducts, is provided with larger parts (such as dual-layer flexible joints) at two ends, can not have larger holes in structure and adopts a joint connection form. The joint comprises a small flange, a large flange, two sealing rubber rings and a sealing rubber pad, wherein two rings of bulges are uniformly arranged on an external plate of the large flange; a sealing trough is arranged on the internal wall of a chamber body of the large flange; the small flange comprises a straight pipe and a flange plate; an external plate of the small flange is provided with assembling holes that are matched with the internal ring bulges of the external plate of the large flange; one end of the straight pipe of the small flange is connected with the internal wall of the large flange by a sealing ring; and the other end of the straight pipe of the small flange is connected with the duct joint. In the split type over-frame dual-layer joint, by adopting the split type structure, passing holes of the structure can be reduced; various sealing forms such as a rubber pad, a bulge structure, the dual rubber rings, sealing rubber and the like are adopted, furthermore, fuel in an oil tank does not need to be discharged when the dual-layer joint is being replaced, so that the split type over-frame dual-layer joint has the advantages of being sealed firmly, being disassembled and assembled conveniently, and the like, and the using and the flying safety of an aircraft can be ensured.