A nozzle apparatus, comprising: 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 (12, 112) defining a bore with an internal cross-sectional area, wherein the internal cross-sectional area of the bore defined by the tube is the same along at least 75 % of its length; the tube having: - a inlet (18, 118) to the tube (12,112), the inlet (18,118) being positioned through the first end of the tube and the inlet having a first inlet cross-sectional area which is less than the cross-sectional area of the bore defined by the tube; - an outlet (16,116) from the tube (12,112) at the second end, the outlet (16, 116) 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; - a nozzle with a nozzle outlet, the nozzle outlet having a nozzle outlet cross-sectional area, wherein the filter (10, 110) is connected to the nozzle; and - wherein the inlet cross-sectional area of the filter (10,110) is smaller than the outlet cross-sectional area of the nozzle; 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 the nozzle and out of the nozzle outlet. 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 (12, 112) defining a bore with an internal cross-sectional area, wherein the internal cross-sectional area of the bore defined by the tube is the same along at least 75 % of its length; - 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 (12, 112) defining a bore with an internal cross-sectional area, wherein the internal cross-sectional area of the bore defined by the tube is the same along at least 75 % of its length; the tube having: - a inlet (18, 118) to the tube (12,112), the inlet (18,118) being positioned through the first end of the tube and the inlet having a first inlet cross-sectional area which is less than the cross-sectional area of the bore defined by the tube; - an outlet (16,116) from the tube (12,112) at the second end, the outlet (16, 116) 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; - a nozzle with a nozzle outlet, the nozzle outlet having a nozzle outlet cross-sectional area, wherein the filter (10, 110) is connected to the nozzle; and - wherein the inlet cross-sectional area of the filter (10,110) is smaller than the outlet cross-sectional area of the nozzle; and, - a inlet (18, 118) to the tube (12,112), the inlet (18,118) being positioned through the first end of the tube and the inlet having a first inlet cross-sectional area which is less than the cross-sectional area of the bore defined by the tube; - an outlet (16,116) from the tube (12,112) at the second end, the outlet (16, 116) 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; - a nozzle with a nozzle outlet, the nozzle outlet having a nozzle outlet cross-sectional area, wherein the filter (10, 110) is connected to the nozzle; and - wherein the inlet cross-sectional area of the filter (10,110) is smaller than the outlet cross-sectional area of the nozzle; and, - wherein the inlet cross-sectional area of the filter (10,110) is smaller than the outlet cross-sectional area of the nozzle; 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 the nozzle and out of the nozzle outlet.