Inflow fitting

An inflow fitting for the filling of a cistern, comprising

• a housing,
• an outlet pipe coupled to the housing,
• a water passage arranged through the housing and the outlet pipe, and the housing having an entry to the water passage, and the outlet pipe having an exit from the water passage,
• a float-controlled valve, which is arranged in the water passage and which shuts off or opens up the water passage in a filling operation, and
• a float, which cooperates with the valve, for controlling the valve, wherein the float has a cavity, which is fillable with water, and at least one buoyancy chamber,
• wherein the inflow fitting further comprises a supplemental water tap, branched off from the water passage, for filling the cavity in order to provide an additional weight on the float,
• wherein in the water passage, in a region of the supplemental water tap, at least one backflow element is arranged, with which a backflow can be provided in a region of the supplemental water tap for a pressure-independent removal of supplemental water, and
• wherein a cross section of the water passage, viewed in a direction of flow, extends conically after the backflow element, the conicity being such that the cross section of the water passage reduces with increasing distance from the backflow element.