Abstract: The invention relates to a method for recovering the metal values from materials containing at least one of zinc and tin, by smelting the starting materials under oxidizing conditions and reducing the resultant molten bath. The starting materials are first smelted in a furnace while adding flux, to form a slag which is sluggish at selected reduction temperatures and has a low lead contents. The reduction process is carried out while charging solid carbonaceous reduction agent and optionally also sulphur- and/or chlorine-donor material to the slag. The reduction agent and optionally supplied donor material is brought into suspension with the slag, and this suspension is sustained at least during the latter phase of the reduction period, at which the lead content of the slag has fallen to beneath about 1-2%, during which phase the reduction of zinc and tin takes place.

Abstract: For trowelling concrete spread over a floor, a trowelling device is used, which includes a carrier having a cantilever arm swingable over the floor. At the distal end of the arm a rotatable trowelling member is carried in a pedestal structure permitting vertical adjustment of the floor contacting parts. A laser sends a horizontal beam at a predetermined level over the floor, and an upwardly directed measuring rod at the housing of the trowelling member is provided with a detector for catching the beam, and for transferring deviations of the beam from a mark thereon into signals for adjusting the position of the trowelling member.

Abstract: A ventilation element for example a valve is anchored in an opening in a ceiling or wall of limited thickness by means of a connecting piece in form of a cylindric pipe with a stop flange and equipped with a plurality of elongated, narrow wings of a resilient material and tangentially projecting from the shell surface and arranged to be pressed towards said surface momentarily during the insertion by a screwing motion of said pipe and then -- after final insertion -- said wings extending radially along one border line against the rear side of said ceiling or wall.

Abstract: A folding sport stroller, comprising at least one pair of angular supporting legs pivotally mounted in relation to one another, in the supporting end of which wheels, pivoted on wheel axles at right angles to the supporting legs, are arranged, the first supporting leg, for instance the rear one, being extended upwards beyond the pivoting shaft between the legs, the extension carrying a blocking lever pivoted on it, which has a locking part in engagement with a locking device adjacent the other leg, when the stroller is in ready to use-state so that the extension of the supporting leg, the portion of the blocking lever between said extension and the locking part as well as the part of the other supporting leg between the locking device and its pivot in the first leg, in the said state of the stroller, generally form a triangle-shaped locking construction maintaining the supporting legs in a fixed position in relation to each other.