A bypass device for an absorption tank comprises a two-position three-way valve, a micro switch, a control circuit board, and a micro switch actuation mechanism. When an absorption tank needs to be replaced, in the process of rotating a handle, a contact wheel of the micro switch is pressed to send an electrical signal to the control circuit board, and the control circuit board controls a solenoid valve, thereby controlling a gas path of the two-position three-way valve, and bypassing the absorption tank effectively and timely. After the absorption tank is replaced, it is only required to rotate the handle to the original position, so that the entire replacement process involves simple operations and is effective, and the sealing effect of the gas path is desirable.
