Disclosed is filter having a filter core, a top cover, a bottom cover, at least one first discharging pipe and at least one second discharging pipe, wherein the filter core has a slot through which a fluid to be filtered passes; the top cover and the bottom cover are respectively fixed to an upper portion and a lower portion of the filter core; an inner wall surface of the filter core, an inner wall surface of the top cover and an inner wall surface of the bottom cover define a filter cavity; the first discharging pipe has at least one first inlet through which the fluid flows in; the second discharging pipe has at least one second inlet through which the fluid flows in; and all the first inlets are situated above the second inlets in the gravity direction. The filter can realize the separation of two fluids.