Adjustable flange device for flue gas sampling gun

The utility model provides an adjustable flange device for a flue gas sampling gun, an upper half flange comprises an upper half disc body, one side of the upper half disc body is provided with an upper half cylindrical table which is coaxially arranged with the upper half disc body, and one end of the upper half disc body is provided with an upper connecting block which extends along the radial direction of the upper half disc body; the lower half flange comprises a lower half disc body, the diameter of the lower half disc body is equal to that of the upper half disc body, and a lower half cylindrical table which is coaxial with the lower half disc body and located below the upper half cylindrical table is arranged on one side of the lower half disc body; lower connecting blocks staggered with the upper connecting blocks are arranged at the positions, corresponding to the upper connecting blocks, of the lower half disc body, the upper connecting blocks and the lower connecting blocks are connected in a rotat