Spray header intended to lubricate and/or cool a rolled strip and/or rolls of a rolling mill, comprising: - a tubular shaft, the hollow interior volume whereof forms a fluid intake chamber (Ca), - a chassis rigidly connected to the external wall of the shaft, extending along said tubular shaft, - a plurality of nozzles distributed over the length of the chassis and supported by the chassis, arranged such that the jets form a curtain-like sheet of fluid, - a pipe system, inside said chassis, feeding the nozzles from through-orifices made in the tubular wall of the hollow shaft, characterized in that said pipe system comprises two pressure-levelling chambers (50, 51), wherein the chassis comprises a top wall, a bottom wall, two side walls (32, 33), rigidly connected to in an impervious manner to the external wall of the shaft, in addition to an end wall supporting bores for the plurality of nozzles, said walls (30, 31, 32, 33, 34) of the chassis forming, with the external wall of the tubular shaft, an enclosure, a partition divides the inner volume of the enclosure into said two pressure-levelling chambers (50, 51), in series according to the direction of fluid flow, each whereof extends over the entire active length of the chassis, and through which the totality of the fluid feeding said plurality of nozzles successively passes, including: - a first pressure levelling chamber defined between said partition and the outer wall of the shaft supporting the so-called first orifices, - a second pressure levelling chamber defined between said partition and the end wall, wherein the partition supports so-called second orifices distributed throughout the length of the partition, wherein the number of nozzles forming the plurality of nozzles being an integer N, the number of first orifices and the number of second orifices each being equal to N, wherein each orifice of a nozzle is aligned with one of the first orifices and one of the second orifices, in a direction of alignment that is substantially perpendicular to the axis of the shaft, and such as to allow these three orifices (20, 36, 40) to be cleaned by inserting the same rectilinear tool (Or) simultaneously passing through these three openings (20, 36, 40) in the direction of alignment, and wherein: - the machining of said first orifices are inclined relative to the direction of alignment such that each of the jet outputs of the orifices is directed against a solid wall of the first levelling chamber such as the partition, - the machining of said second orifices of the intermediate partition are inclined relative to the direction of alignment such that each of the jet outputs of the orifices is directed against a solid wall of the second levelling chamber, such as the end wall. - a tubular shaft, the hollow interior volume whereof forms a fluid intake chamber (Ca), - a chassis rigidly connected to the external wall of the shaft, extending along said tubular shaft, - a plurality of nozzles distributed over the length of the chassis and supported by the chassis, arranged such that the jets form a curtain-like sheet of fluid, - a pipe system, inside said chassis, feeding the nozzles from through-orifices made in the tubular wall of the hollow shaft, characterized in that said pipe system comprises two pressure-levelling chambers (50, 51), - a first pressure levelling chamber defined between said partition and the outer wall of the shaft supporting the so-called first orifices, - a second pressure levelling chamber defined between said partition and the end wall, - the machining of said first orifices are inclined relative to the direction of alignment such that each of the jet outputs of the orifices is directed against a solid wall of the first levelling chamber such as the partition, - the machining of said second orifices of the intermediate partition are inclined relative to the direction of alignment such that each of the jet outputs of the orifices is directed against a solid wall of the second levelling chamber, such as the end wall.