Alcan International Limited

Marc Auger

Jean Perron

Yves Caron

Ghyslain Dube

Luc Parent

Andre Gendron

Bruno Gariepy

Daniel Baril

Friedrich Muller

Marc-Andre Thibault

A method of controlling a temperature of a surface of a direct chill cast ingot cast in an open-ended mold provided with a bottom block during early stages of casting as the ingot emerges from the open-ended mold. The method involves the steps of directing a flow of a coolant onto at least one surface of an ingot emerging from an open-ended mold to impinge on the surface at a normal impingement point and to cool the surface, measuring a surface temperature on the emerging ingot at at least one measurement location which is at a predetermined position close enough to the normal impingement point to be affected by the secondary coolant, to generate a measured surface temperature, determining the displacement of the bottom block of the casting machine from its initial position at the start of the cast, corresponding to each the surface temperature measurement, and using the measured surface temperature to control a casting variable and thereby to control the temperature of the surface. The invention also relates to apparatus for carrying out the above method and to a method of measuring the surface temperature.

Method and apparatus for controlling the temperature of an ingot during

Apparatus for measurement of a temperature of a moving metal slab to provide a measured temperature indication corresponding to an actual temperature at a location on the surface of the slab. The apparatus comprises a first temperature measuring sensor mounted to move out of contact with a surface of the slab, and then into contact with the surface at the location, the first sensor generating an output corresponding to a detected temperature when the contact is made with the surface; at least one additional temperature measuring sensor mounted adjacent to the first sensor to move out of contact with the surface of the slab, and then into contact with the surface at the location, the second sensor generating an output corresponding to a detected temperature when the contact is made with the surface; and a comparator for determining whether or not the detected temperatures at the location differ by less than a particular amount, and for providing a measured temperature indication representing the actual temperature of the surface at the location based on one or more of the outputs, only if the detected temperatures differ by less than the predetermined amount. The invention also relates to a corresponding method of measuring the surface temperature.

Apparatus and method for measuring the temperature of a moving surface

A process and control system for controlling a rotary calcining kiln having a feed material inlet for material to be calcined, a calcined product outlet and a high temperature zone in which said material is calcined, the high temperature zone being movable within the rotary calcining kiln according to changes in operational control variables of the rotary calcining kiln. The process comprises measuring temperatures within the rotary calcining kiln at various positions spaced from each other along the rotary calcining kiln in a region overlapping a predetermined desired position for the high temperature zone, and adjusting the control variables to move the high temperature zone to the desired position when the high temperature zone deviates from the desired position. In the process, the temperatures are measured by thermocouples having thermocouple junctions protected by heat and abrasion resistant sheaths, preferably made of alumina/silicon carbide ceramics, positioned within the rotary calcining kiln.

Process for controlling rotary calcining kilns, and control system

A temperature measuring device for measuring the temperature of an abrasive particulate material of the type found, for example, in rotary calcining kilns and the like. The device comprises a temperature sensor producing an indication of a temperature to which the sensor is exposed, circuitry or the like for connecting the temperature sensor to remote equipment for converting the indication to a recognisable form and a protective element shielding the temperature sensor from damage by the abrasive particulate material. The protective element comprises a layer of ceramic material having a matrix of alumina reinforced with 5 to 50% by volume (based on the total volume of the ceramic material) of particles of silicon carbide having an average size, at least in two dimensions, within the range of about 5 to 60 microns. The protective element provides good abrasion, heat-shock and mechanical resistance while exhibiting sufficient thermal conductivity to avoid undue inaccuracies in the temperature measurements.

High temperature and abrasion resistant temperature measuring device

The invention provides a new stirring apparatus for stirring the liquid metal contents of a furnace, particularly the shallow furnaces used in the processing of aluminum and its alloys. The apparatus consists a reservoir separate from the furnace of relatively large horizontal cross-section and volume, into which a vaccuum draws metal from the furnace through a nozzle, the metal then being returned by gas pressure forcibly into the furnace through the nozzle in the form of a horizontally directed jet. The cycle is repeated at sufficiently close intervals to ensure that the furnace bath is quickly and effectively mixed. The nozzle directs the molten metal entering the reservoir tangentially to swirl the metal and reduce the accumulation of dross. The reservoir comprises a bottom static part including the nozzle and a readily removable top cover carrying heaters for heating the reservoir interior and the dross that deposits on the side wall to ease its removal. The cover also carries level control electrodes, an observation port, inlet ports, etc. A pressure disturbance monitor connected to the reservoir interior is used for lower level control by detecting undesired bubbling of the pressurizing gas into the metal, and can also be used to monitor the pressure reversals between vacuum and pressurization phases. The cycles of vaccuum and pressure are controlled in a manner that maximizes the quantity of metal entering the reservoir so as to obtain the maximum stirring effect.

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Jonquiere, Canada

Marc Auger