Abstract: The invention relates to a hot-air fan including a fan device for generating an air flow, a heating device for heating the air flow, and a control unit connected to the fan device and to the heating device. In this process, the control unit is designed to control the fan device in such a manner that, when the heating device is switched on, the fan device generates a starting air flow that is reduced to an operating air flow. The invention also relates to a method for operating the hot-air fan, including the steps of switching on the heating device and generating a starting air flow that is reduced to an operating air flow.

Abstract: A pair of conveyor screws for rotating positive-displacement pumps, the conveyor screws including a rotor and a contra-rotor, wherein the conveyor screws comprise a screw spindle pump and rotate with zero contact in a bore and in flanks and rotate at the same speed, the conveyor screws form loss gaps and have the same thread depth, the same number of threads and flank profiles which are symmetrical. The conveyor screws include a tooth base positioned below a flank profile reversing point and a tooth head positioned above the flank profile reversing point, wherein a profile-produced loss gap height in an axial section on a pitch circle is kept constant for a specific rotor diameter by shifting the flank profile reversing point as a function of a rotor pitch.

Abstract: A flexible bonnet portable hair dryer including two separate combination blower and heater units. A flexible U-shaped collar support is connected to the combination blower and heater units and to a lower edge of the bonnet.

Abstract: A hair dryer comprising a generally tubular housing including twogenerally semi-cylindrical grip parts having edges including complimentary grooves and projections which engage each other to secure the grip parts together, the housing accommodating a heating device, a motor and an air transport device therein, a first end grid which is mounted over an intake opening on one end of the housing to secure the grip parts to the first grid as well as to each other, and a second end grid mounted over an exhaust opening at the other end of the housing to secure the semi-cylindrical grip parts to the second grid as well as to each other.