Alcan International Limited

Andre Gendron

Thierry Bourgeois

Yves Caron

Marc Auger

Joseph Langlais

Bruno Gariepy

Luc Belley

Serge Munger

Marc-Andre Thibault

A method of measuring the quenchability of a liquid coolant used to cool objects such as ingots produced by direct-chill casting. The method involves providing a sample of the liquid coolant; providing a probe for immersion in the sample, the probe having a temperature-sensing electrical device contained therein which generates an electrical response corresponding to temperature sensed; heating the probe in a gas, preferably by means of electrical resistance heating by a circuit which is electrically connected to the temperature-sensing electrical device, to a predetermined temperature measured by the electrical response of the temperature sensing device, immersing the probe into the sample and measuring the electrical response for a predetermined measurement period, and comparing the measured electrical response to a response of a reference liquid measured under equivalent conditions, to thereby determine the quenchability property of the liquid coolant. The invention also relates to apparatus for carrying out the method, as well as a method and apparatus for controlling the cooling of the object based on the measured quenchability of the coolant. In an alternative, the probe may be heated by means other than the electrical resistance heating at a rate of at least about 40&deg; C./second.

Method and apparatus for measuring quenchant properties of coolants

A method of measuring the quenchability of a liquid coolant used to cool objects such as ingots produced by direct-chill casting. The method involves providing a sample of the liquid coolant; providing a probe for immersion in the sample, the probe having a temperature-sensing electrical device contained therein which generates an electrical response corresponding to temperature sensed; heating the probe in a gas, preferably by means of electrical resistance heating by a circuit which is electrically connected to the temperature-sensing electrical device, to a predetermined temperature measured by the electrical response of the temperature sensing device, immersing the probe into the sample and measuring the electrical response for a predetermined measurement period, and comparing the measured electrical response to a response of a reference liquid measured under equivalent conditions, to thereby determine the quenchability property of the liquid coolant. The invention also relates to apparatus for carrying out the method, as well as a method and apparatus for controlling the cooling of the object based on the measured quenchability of the coolant. In an alternative, the probe may be heated by means other than the electrical resistance heating at a rate of at least about 40.degree. C./second.

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.

Apparatus for stirring molten metal

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Jonquiere, Canada

Andre Gendron