A filter (10, 110) comprising: a tube (12, 112) extending from a first end to a second end, the first end being tapered, that is the centre of the first end extends longitudinally further than an outer portion of the first end, the tube defining a bore with an internal cross-sectional area, the tube having: an inlet (18, 118) to the tube (12, 112), the inlet being positioned through the first end of the tube (12, 112), and the inlet having an inlet cross-sectional area; an outlet (16, 116) from the tube (12, 112) at the second end, the outlet having an outlet cross-sectional area; a plurality of slots (20, 120) in the tube (12, 112) between an outside thereof and the bore, the slots extending generally parallel to the longitudinal direction from the first to the second end; the tube (12, 112) comprising a mounting means suitable for mounting it to a pipeline, the mounting means comprising a threaded outer body; the tube (12, 112) comprising a further mounting means suitable for attaching a nozzle thereto; wherein the inlet cross-sectional area is less than the outlet cross-sectional area, the inlet cross-sectional area is less than the internal cross-sectional area of the bore defined by the tube; wherein the internal cross-sectional area of the bore defined by the tube (12, 112) is the same along at least 75% of its length; and wherein, in use, the fluid flows from a pipeline into the filter through the inlet (18, 118) and the plurality of slots (20, 120), through the bore of tube (12, 112), and out of the filter through the outlet (16, 116) into a nozzle. a tube (12, 112) extending from a first end to a second end, the first end being tapered, that is the centre of the first end extends longitudinally further than an outer portion of the first end, the tube defining a bore with an internal cross-sectional area, the tube having: an inlet (18, 118) to the tube (12, 112), the inlet being positioned through the first end of the tube (12, 112), and the inlet having an inlet cross-sectional area; an outlet (16, 116) from the tube (12, 112) at the second end, the outlet having an outlet cross-sectional area; a plurality of slots (20, 120) in the tube (12, 112) between an outside thereof and the bore, the slots extending generally parallel to the longitudinal direction from the first to the second end; an inlet (18, 118) to the tube (12, 112), the inlet being positioned through the first end of the tube (12, 112), and the inlet having an inlet cross-sectional area; an outlet (16, 116) from the tube (12, 112) at the second end, the outlet having an outlet cross-sectional area; a plurality of slots (20, 120) in the tube (12, 112) between an outside thereof and the bore, the slots extending generally parallel to the longitudinal direction from the first to the second end; the tube (12, 112) comprising a mounting means suitable for mounting it to a pipeline, the mounting means comprising a threaded outer body; the tube (12, 112) comprising a further mounting means suitable for attaching a nozzle thereto; wherein the inlet cross-sectional area is less than the outlet cross-sectional area, the inlet cross-sectional area is less than the internal cross-sectional area of the bore defined by the tube; wherein the internal cross-sectional area of the bore defined by the tube (12, 112) is the same along at least 75% of its length; and wherein, in use, the fluid flows from a pipeline into the filter through the inlet (18, 118) and the plurality of slots (20, 120), through the bore of tube (12, 112), and out of the filter through the outlet (16, 116) into a nozzle.