Negative pressure pipeline water-gas automatic separating system

The invention relates to a negative pressure pipeline water-gas automatic separating system, a water-gas separator and automatic draining equipment. The automatic draining equipment is detachably movably connected with a connecting part. The connecting part is provided with an external connecting portion and at least one through inner wall, and the edge of the inner wall is circular. The automatic draining equipment comprises an outer sleeve, a screen tube and a floating ball, wherein the outer sleeve is movably connected with the external connecting portion, a draining outlet is formed outside the outer sleeve, the screen tube is mounted in the outer sleeve and provided with a hollow part and a stopping part, the floating ball is disposed in the screen tube in a floating manner and stopped from leaving the screen tube by the stopping part, the diameter of the floating ball is larger than that of the edge of each inner wall of the connecting part, the floating ball seals the edge of the inner wall of the connecting part when the floating ball moves to a first extreme position, and the floating ball cannot block the whole hollow part of the screen tube when the floating ball moves to a second extreme position. By the negative pressure pipeline water-gas automatic separating system, the water-gas separator and the automatic draining equipment, cost and energy consumption are reduced, and pollution is reduced.