A pipe-within-a-pipe and method of use are provided. The pipe-within-a-pipe comprises a first tube overlaying a second tube. The first tube and the second tube have different structures in some respect.

A rotary hearth furnace includes a unit that supplies an agglomerate onto a hearth of the rotary hearth furnace, a unit that discharges a heated substance which has been heated in the rotary hearth furnace to the outside of the furnace, and a unit that discharges an exhaust gas in the rotary hearth furnace to the outside of the furnace. The rotary hearth furnace has a heating section and a non-heating section. The unit that discharges an exhaust gas to the outside of the furnace is provided in the non-heating section. A unit that takes an outside air into the furnace is provided in the non-heating section and on an upstream side in a flow direction of the exhaust gas from the unit that discharges exhaust gas to the outside of the furnace.

A rotary hearth furnace includes a unit that supplies an agglomerate onto a hearth of the rotary hearth furnace, a unit that discharges a heated substance which has been heated in the rotary hearth furnace to the outside of the furnace, and a unit that discharges an exhaust gas in the rotary hearth furnace to the outside of the furnace. The rotary hearth furnace has a heating section and a non-heating section. The unit that discharges an exhaust gas to the outside of the furnace is provided in the non-heating section. A unit that takes an outside air into the furnace is provided in the non-heating section and on an upstream side in a flow direction of the exhaust gas from the unit that discharges exhaust gas to the outside of the furnace.

An arc furnace having a furnace vessel for melting steel, a cover for closing the furnace vessel and a pivot unit with which the cover can be moved away from the furnace vessel in which the furnace vessel is mounted so as to be movable in the vertical direction relative to the pivot unit, and the pivot unit has a holder for releasably fixing the cover in the vertical direction.

An arc furnace having a furnace vessel for melting steel, a cover for closing the furnace vessel and a pivot unit with which the cover can be moved away from the furnace vessel in which the furnace vessel is mounted so as to be movable in the vertical direction relative to the pivot unit, and the pivot unit has a holder for releasably fixing the cover in the vertical direction.

A tilting converter comprising a container (2), defining a first longitudinal axis X, having a bottom (2); a support ring (3), coaxial to the container (2) and distanced from said container, provided with two diametrically opposite supporting pins (6), defining a second axis Y orthogonal to the first axis X, adapted to allow a rotation of the converter about said second axis Y; a suspension system, connecting said container (2) to said support ring (3), comprising groups (12) of first suspension devices (7), said groups (12) being arranged substantially equidistant to each other along a cylindrical side surface coaxial to the first axis X, in a position between the support ring (3) and the bottom (2); each of said first suspension devices (7) being provided with a plurality of longitudinal elastic elements, each longitudinal elastic element being arranged alongside the next so as to define a laying plane, and a gap (15, 15) is provided between one longitudinal elastic element and the next.

An arc melting and tilt casting apparatus having a casing provided with a vacuum chamber for housing a hearth having a melting trough and pouring means, arc-melting electrode means passing through the casing in the chamber, a mold having a melt receiving orifice, vacuum generating means, sealing means for maintaining the vacuum in the chamber and tilting means for tilting the apparatus to cause the melt to flow from the melting trough via the pouring means in the mold through the mold orifice. The hearth and mold are connected together and moveable as a single unit in the vacuum chamber and out from the chamber.

A melting hearth includes high temperature walls, a melting cavity having a specific topography, and conformal fluid cooling passages configured to provide a flow path for a cooling fluid that is substantially parallel to the topography of the melting cavity. In addition, the topography of the melting cavity mirrors a heat signature of a heat source used to melt a feed material in the melting hearth into a molten metal. A cold hearth melting system includes the melting hearth, a magnetic stirring system, the heat source having the heat signature, a tilting mechanism for tilting the melting hearth to a desired tilt angle, and a fluid cooling system having a fluid source in flow communication with the conformal fluid cooling passages. A process for producing high temperature metal alloys uses the cold hearth melting system and an algorithm for controlling the pouring of the molten metal from the melting hearth.

The present disclosure concerns expandable silica particles having a coating comprising talc powder and kaolin powder provided on the outer surface of the expandable silica particle and expandable and expanded silica particles comprising silica fume and/or ultrafine quartz silica sand beneath the surface of the particles. Methods for producing expandable and expanded silica particles are disclosed, including a method using a vibration plate and a furnace having a vibration plate for carrying out that method. The expanded silica particles have high compressive strength, substantially uniform cell size and distribution, low water absorption, and low porosity on the outer surface. They are useful as a filler in matrix materials, like concrete or epoxy, as insulation material with various binder materials, and as water filtration medium.

The present disclosure concerns expandable silica particles having a coating comprising talc powder and kaolin powder provided on the outer surface of the expandable silica particle and expandable and expanded silica particles comprising silica fume and/or ultrafine quartz silica sand beneath the surface of the particles. Methods for producing expandable and expanded silica particles are disclosed, including a method using a vibration plate and a furnace having a vibration plate for carrying out that method. The expanded silica particles have high compressive strength, substantially uniform cell size and distribution, low water absorption, and low porosity on the outer surface. They are useful as a filler in matrix materials, like concrete or epoxy, as insulation material with various binder materials, and as water filtration medium.