Air treatment device and system, control method and equipment and railway vehicle

The embodiment of the invention provides an air treatment device and system, a control method and equipment and a railway vehicle. The air treatment device comprises a shell, an air channel partition plate is arranged in the shell, and the space in the shell is divided into a bent ventilation channel; the shell is provided with an air inlet and an air outlet which are communicated with two ends of the ventilation channel; a liquid collecting space is formed at the bottom of the shell, is communicated with the ventilation channel and is positioned at the front end of the air outlet; a filter screen is arranged in the shell and is positioned on the ventilation channel between the liquid collecting space and the air outlet; a liquid discharging pipeline is arranged at the bottom of the shell and is communicated with the liquid collecting space; a switch valve is arranged on the liquid discharge pipeline; and a liquid level sensor is arranged on the shell, and the liquid level detection end of the liquid level se