A method for operating a dirt collecting device for a sweeping vehicle or for a vacuum cleaner nozzle of a floor or upright vacuum cleaner, the method comprising:
- in a first method step, providing the dirt collecting device consisting of a housing which is slidable over a floor plane, a suction fan configured to operate in variable speeds at variable power levels, a collection container connected to the housing, at least one rotatingly driven sweeper roller or brush roller arranged in the housing which inputs the coarse and fine dirt from the floor plane into the housing and, supported by a suction airflow of the suction fan, conveys the suction airflow into the collection container, an intermediate container configured to be emptied by operation of the suction fan, the intermediate container comprises a front wall, a rear settling wall, and two side boundaries between the front wall and the rear settling wall, and the intermediate container is disposed in the suction airflow of the suction fan between the at least one rotatingly driven sweeper roller and the collection container and arranged in the housing of the dirt collecting device for temporary intermediate storage of coarse dirt, the collection container arranged downstream of the intermediate container, a suctioning connection channel connected between the intermediate container and the collection container, and a sensor electrically connected to the suction fan and arranged in the intermediate container, to detect a filling level of the input coarse dirt in the intermediate container and to generate a sensor signal that is sent to the suction fan when the filling level exceeds a maximum permissible filling level, wherein the two side boundaries of the intermediate container taper inwardly between the front wall and the rear settling wall toward the suctioning connection channel, wherein the settling wall extends between a floor of the intermediate container and an inlet opening of the suctioning connection channel and has a height that is less than a height of the front wall, wherein the suction fan is configured to operate in the following modes:
- 1) a normal operation, responsive to absence of the generated sensor signal indicating that the maximum permissible filling level of the intermediate container is not exceeded, in which the suction power of the suction fan is set at a low level such that the suction pressure in the dirt collecting device is merely sufficient to convey and deposit the input coarse dirt into the intermediate container, and to convey the input fine dirt into the collection container;
- and 2) an emptying mode, responsive to the generated sensor signal indicating that the maximum permissible filling level in the intermediate container is exceeded, in which the suction power of the suction fan is increased such that the input coarse dirt, which is temporarily deposited in the intermediate container, becomes dispersed and is conveyed from the intermediate container into the collection container to thereby empty the intermediate container,
- in a second method step, which correspond to the normal operation, the suction power of the suction fan is set at such a low level that the suction pressure in the dirt collecting device or the vacuum cleaner nozzle is merely sufficient to convey and deposit the absorbed coarse dirt into the intermediate container, and to convey the absorbed fine dirt into a downstream collection container;
- in a third method step, the filling level in the intermediate container is detected with respect to the coarse dirt deposited therein;
- in a fourth method step, which corresponds to the emptying mode, if the filling level in the intermediate container is exceeded, the suction power of the suction fan is increased such that the coarse dirt, which is temporarily deposited in the intermediate container, becomes dispersible and is conveyed into the downstream collection container.