Abstract: In a process of hot-rolling steel wherein use is made of a heat-reflecting screen (13) by which heat radiating from the work (1) is reflected back to the work, the invention comprises the step of cooling the heat-reflecting-surface (10) of the screen during use, e.g. by flowing fluid coolant along the paths (18) in heat-conducting relationship to such heat-reflecting surface.

Abstract: In an arrangement for mixing a first gas into a main flow of a second gas, comprising a main conduit for said main flow and a plurality of supply conduits for the first gas which open into said main conduit, the supply conduits are arranged as at least one set of three outlet openings. This set consists of a first opening which opens into the main flow perpendicularly to the main conduit wall and two second openings which are arranged so as each to provide a lesser flow rate of the first gas than the first opening and are offset with respect to the first opening. The three openings of the set thus direct the first gas into two contra-rotating circulatory movements, as viewed in the direction of the axis of the main conduit. This mixing arrangement is applicable for example to mixing a hot gas into the gas obtained from an ore pellet drying bed and to mixing a hot gas into a water-laden gas from a desulphurization plant.

Abstract: To achieve uniform gas flow in a chamber to which gas is fed from a cylindrical pipe, the pipe has a closed end wall, at least two spaced rectangular apertures on one side near said end wall and, between each adjacent pair of apertures, a radial partition wall, having a central circular aperture. The arrangement is applicable to gas flow to a gas burner or a gas filter.

Abstract: Gas is mixed into a main flow of gas in a cylindrical conduit by means of one or more feed conduits. In order to achieve good mixing and avoid concentrations of the added gas, the feed conduit(s) have two openings for outflow of the added gas, which openings are spaced from the wall of the cylindrical conduit, are symmetrically located with respect to the axis of the cylindrical conduit and lie in a plane perpendicular to that axis. The axis of these openings are mutually spaced by less than one half of the internal diameter of the conduit. The added gas emerges from the two openings in mutually opposite parallel directions, so that it tends to circulate around the axis. The arrangement has been found advantageous when applied to the feed of gaseous fuel to hot blast stoves of a blast furnace.