Gas source switching device

The utility model belongs to the technical field of gas conveying, and particularly relates to a gas source switching device which comprises a first gas inlet pipe, a second gas inlet pipe and a gas exchange device, the first gas inlet pipe and the second gas inlet pipe are both assembled on the gas exchange device, a gas supply pipeline is connected to the gas exchange device, and a load is assembled at the other end of the gas supply pipeline. The side wall of the ventilation device is further connected with a trigger device, and a trigger signal is arranged in the trigger device. The ventilation device comprises a round shell, a round plate is arranged in the round shell, rotating shafts are fixedly connected to the centers of the upper side wall and the lower side wall of the round plate, the other ends of the rotating shafts are rotationally connected with the round shell, the top end of the rotating shaft on the upper side penetrates through the round shell and is provided with a control assembly, and a