Abstract: A safety vacuum cleaner including a measuring system for residual dust monitoring, including a housing having an air passage with an inlet, an outlet, and a flow cross section. A turbine is disposed within the air passage and is rotatable to move an air stream through the air passage, the air stream containing dust particles. The turbine is electrically grounded such that electrical charges associated with the particles are removed upon contact of the particles with the turbine. A filter element is disposed within the air passage, and at least one electrode is disposed within the air passage downstream of the turbine, the electrode shaped as a grid covering the flow cross section of the air passage. The electrode conducts an electrical current responsive to contact with uncharged particles and emits a measurement signal indicative of the amount of the particles in the air stream.

Abstract: A riding type sweeper with a rear-mounted engine and a driven sweeper roller located between the front axle and the rear axle, wherein the sweeper roller transports the dirt into a coarse dirt container disposed behind the sweeper roller, from which the fine dirt is suctioned off by a filter blower unit. The filter blower unit is arranged in the region before the rear-mounted engine in a vertically superpositioned arrangement, with the blower turbine together with the fine filter being arranged in a common box.

Abstract: An electronically commutated motor for dust exhausters with a stator with excitation windings and with a rotor positioned to rotate in an air gap. The rotor has bundled laminations and permanent magnets around its circumference corresponding to the number of poles of the stator. A fan rotor of a ventilator is also provided on the rotor shaft, with the fan rotor connected downstream from the motor in the intake direction of the cooling air. The rotor shaft is connected with a turbine for generation of an intake air current, wherein the fan rotor is positioned in the upper bearing plate of the turbine. The bearing plate is designed in one piece in immediate vicinity of the turbine rotor and has indentations and cutouts in a radially outward direction, whereby air currents of the fan rotor and the turbine rotor flow each from its respective side, with the exit slots for cooling air from the fan rotor and the outlets for the exhaust from the turbine going out from the bearing plate.

Abstract: A high pressure cleaning equipment will be described which can be operated by either hot water or superheated steam with the addition of cleaning chemicals as required. For increased safety of operation of the equipment, a safety valve is additionally provided together with, as required, a steam valve, which in the case of steam operation, directs only a noticeably reduced amount of cleaning fluid per unit of time to a heat exchanger which converts the cleaning fluid to steam.