Abstract: Disclosed is an improved 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, which communicates with the filter cavity and is provided at the top cover, has at least one first inlet through which the fluid flows in; the second discharging pipe, which communicates with the filter cavity and is provided at the top cover or the bottom cover, 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.