Zero-residue sight glass

The utility model relates to the technical field of sight glasses, and discloses a zero-residue sight glass which comprises a pipeline body, a sight glass pipe is arranged on the pipeline body, second fixing plates are installed at the two ends of the sight glass pipe respectively, second lenses are installed in the two second fixing plates respectively, one side of each second fixing plate is fixedly connected with a fixing frame, and the other side of each second fixing plate is fixedly connected with a second lens. And baffles are slidably connected to one sides of the two fixing frames correspondingly, movable plates are arranged on one sides of the two second lenses correspondingly, and sponge blocks are installed on one sides of the two movable plates correspondingly. The first threaded rod rotates, the baffle moves along the first threaded rod, the second lens is exposed, the second threaded rod rotates reversely, the upper portion of the second lens is sealed, the second lens is prevented from being e