Self-adaptive bidirectional suck-back prevention device

The utility model discloses a self-adaptive two-way anti-suck-back device which comprises a bottle body and a bottle cap, the bottle body is cylindrical, the upper end of the bottle body is open, an external thread is arranged at one end, corresponding to the opening, of the outer surface of the bottle body, an internal thread is arranged at the position, corresponding to the external thread, of the inner surface of the bottle cap, and the bottle cap is arranged on the bottle body. By arranging the bottle body and the bottle cap and arranging the first guide pipe and the second guide pipe on the bottle cap, when the suck-back phenomenon occurs and liquid enters the bottle, a liquid drainage device is connected through a mounting base, a floating ball on the liquid drainage device moves along with the liquid level, when the floating ball moves, a connecting rod is driven to pull a movable pipe, and the movable pipe is driven to move. The movable pipe is separated from the limiting ring, liquid in the bottle en