Abstract: In connection with an automatic control device for the cleaning power of a vacuum cleaner, comprising a blower, a blower drive motor and an associated control circuit for the latter, it is proposed to provide two vacuum switches adjusted to different vacuum threshold value or one vacuum double switch presetting the two vacuum threshold values, and to drive a storage (counter, capacitor), whose output configurations determine the manner in which a phase control circuit, which is connected in series with the blower drive motor, is driven, by a corresponding configuration of the switching conditions of the said switches. It is possible in this manner, with only two existing vacuum switches, to operate the blower drive motor at a predetermined power plateau, without any switching actions, so long as the vacuum generated remains within a predetermined window.

Abstract: A device for controlling the operation of a vacuum cleaner and for signalling the dust bag fill level, the existence a clogged pipe or of secondary air openings, or the like has an air turbine arranged in the exhaust air flow generated by the blower of a vacuum cleaner, downstream of the dust bag, whose rotary speed or the air turbine is detected in a non-contact manner, converted into an electric indication signal and supplied to a control circuit which controls the blower motor. Based upon the rotary speed so detected, it is then possible to determine the momentary operating conditions of the vacuum cleaner and/or the dust bag fill level, to emit signals warning the operator that the dust bag has to be changed, and also to display finely graded percentage statements or applicable text messages for the user. By combining this information with pressure values picked up by diaphragm-type switches, it is possible to accurately determine the operating conditions to be indicated.

Abstract: In connection with a mounting device for sensors and pick-ups generally, serving as dust-detecting means for vacuum cleaners, in particular in the form of luminous diodes and phototransistors arranged adjacent the suction channel of the said vacuum cleaner, it is proposed to form at least one axial channel, leading from the inside to the outside, immediately adjacent the sensor, through which an air flow is passed due to underpressures or overpressures prevailing in the area of the sensor, which air flow acts to continuously clean the sensitive area of the sensor.

Abstract: In connection with a protective circuit for an electrically driven liquid or water vacuum cleaner it is proposed to utilize the abrupt rise of the vacuum, which is encountered when a blocking element interrupts the connection between the receptacle for the liquid and the motor/blower area. The vacuum rise is detected by a diaphragm-type vacuum governor and used for triggering a lockable flip-flop which then interrupts the current supply of the drive motor. The locked condition can be released only by disconnecting the unit from the mains.

Abstract: In connection with a device for desinfecting rooms of any desired type, including the furniture, curtains, floor coverings, carpets, and the like, contained in the rooms, it is proposed to arrange in the suction nozzle of a vacuum cleaner a UV radiator emitting a radiation having a disinfecting action so that any biologically detrimental substances can be fought directly at their place of origin. The UV radiator may be installed in vacuum cleaner nozzles of any kind, i.e. for example in plain floor nozzles, combined suction and beater nozzles, curtain nozzles, and the like.

Abstract: In connection with an optical indication and function monitoring unit for vacuum cleaners comprising optical dust detection means in the form of a luminous diode and a phototransistor provided adjacent the suction duct, and optical indication means for the user, it is proposed to provide, in addition to first delay means for the dust detection means, second delay means having a longer time constant and designed in such a manner that a third flashing luminous diode, which also lights up when the supply battery is nearly run down, is triggered when the dust indication does not operate for an extended period.

Abstract: In a vacuum cleaner for industry and household in which the speed control for the blower motor for the vacuum cleaner is effected by evaluating the dust concentration given at any time in the suction line by opto-electrical means (light transmitters, light receivers) it is proposed to use the signal pulses, which are derived from the light receivers depending on the measured dust particles, for controlling an additional light transmitter (luminous diode) which directly coacts with a light-sensitive resistor which is at the same time part of the control resistance of a triac connected in the motor circuit of the blower motor. Preferably, the optoelectrical dust concentration measuring arrangement may comprise a plurality of light transmitters and light receivers and may be arranged directly adjacent to the air intake opening of a vacuum cleaner housing.