Pressure difference generating apparatus

A pressure difference generating apparatus, comprising:

• a first pipe, defined with an axis, having oppositely a first inlet and a first outlet along the axis and connected spatially to each other;
• a second pipe, having oppositely a second inlet and a second outlet along the axis and connected spatially to each other, disposed coaxially inside the first pipe, a neck portion being disposed between the second inlet and the second outlet, an inner diameter of the neck portion being less than an inner diameter of any of the second inlet and the second outlet, a conical inlet runner being formed between the second inlet and the neck portion, the conical inlet runner being parallel to the axis and tapered from the second inlet to the neck portion, a conical outlet runner being formed between the second outlet and the neck portion, the conical outlet runner being parallel to the axis and tapered from the second outlet to the neck portion;
• and
• a third pipe, having oppositely a third inlet and a third conical outlet portion, the third conical outlet portion having a third outlet, an inner diameter of the third outlet being less than an inner diameter of the third pipe, an outer diameter of the third outlet being less than an outer diameter of the third pipe, the third outlet being parallel to the axis and plugged into the conical inlet runner via the second inlet, the third conical outlet portion being disposed inside the conical inlet runner, an outer diameter of the third pipe being less than an inner diameter of the second inlet;
• wherein the first inlet allows a first fluid to enter the first pipe, the third inlet allows a second fluid to enter the third pipe, the first fluid and the second fluid have different flow rates, a negative pressure generated between the third conical outlet portion and the conical inlet runner has at least part of the first fluid to enter the conical inlet runner via the second inlet, then to enter the neck portion, and finally to enter the conical outlet runner, and the part of the first fluid mixes the second fluid to discharge together out of the second pipe via the second outlet.