Flowrate stabilising monoblock cartridge for hydraulic valves comprising a body with a fluid inlet section , an intermediate section , and a fluid outlet section , wherein: - in the inlet section first openings are obtained for the entry of the fluid into the cartridge , - in the intermediate section a first shutter is provided that reduces the flow of fluid coming from the first openings , is mounted on a diaphragm and is forcibly opened by a calibrated spring , - in the outlet section a second shutter is provided and that is adapted to be controlled by an actuating device that adjusts the fluid flowrate at passage openings within a preset range, - the first shutter has an inner passage that links the first openings to the passage openings and to a first face of the diaphragm , the fluid pressure acting on the first face of the diaphragm being reduced with respect to the pressure entering the cartridge by the reduction action of the first shutter , - the body of the cartridge has second openings to convey the fluid pressure signal downstream of the cartridge to the second face of the diaphragm , - the pressure difference between the first and the second face of the diaphragm determining the movement of the first shutter ; - third pre-adjustable openings are provided in the outlet section for adjusting the fluid flowrate at the outlet of the cartridge , characterized in that the first openings are arranged along an annular wall of the inlet section , the second openings are obtained along another annular wall of the inlet section , and the third pre-adjustable openings comprise an inner ring nut provided with a series of notches of progressively greater dimensions in an annular direction and an outer wall of the outlet section is provided with a series of windows arranged annularly in succession, of the same dimensions, arranged at the notches , the rotational movement of the ring nut with respect to the windows determining the variation in the outlet flow passage area. - in the inlet section first openings are obtained for the entry of the fluid into the cartridge , - in the intermediate section a first shutter is provided that reduces the flow of fluid coming from the first openings , is mounted on a diaphragm and is forcibly opened by a calibrated spring , - in the outlet section a second shutter is provided and that is adapted to be controlled by an actuating device that adjusts the fluid flowrate at passage openings within a preset range, - the first shutter has an inner passage that links the first openings to the passage openings and to a first face of the diaphragm , the fluid pressure acting on the first face of the diaphragm being reduced with respect to the pressure entering the cartridge by the reduction action of the first shutter , - the body of the cartridge has second openings to convey the fluid pressure signal downstream of the cartridge to the second face of the diaphragm , - the pressure difference between the first and the second face of the diaphragm determining the movement of the first shutter ; - third pre-adjustable openings are provided in the outlet section for adjusting the fluid flowrate at the outlet of the cartridge , <EOS>