Abstract: The invention relates to a regulation method for an electrolytic cell for the production of aluminium by means of reduction of alumina dissolved in a molten cryolite bath, wherein a solidified bath ridge is formed on the internal walls of the pot, a quantity B, referred to as the “ridge variation indicator”, which is sensitive to the variation of said solidified bath ridge, is determined and at least one of the setting means of the pot (such as the anode-metal distance) and/or at least one control operation (such as the addition of AlF3) is modified as a function of the value obtained for said indicator. The indicator may be determined from electrical measurements on the pot and/or from measurements of the liquid metal surface area. The method according to the invention makes it possible to regulate an electrolytic cell effectively at currents of up to 500 kA with an electrolyte bath with an AlF3 content greater than 11% and reduce the number of AlF3 content measurements in the bath considerably.

Abstract: The invention relates to a regulation method for an electrolytic cell for the production of aluminium by means of reduction of alumina dissolved in a molten cryolite bath and comprises the addition, in the electrolyte bath, during pre-determined time intervals p referred to as “periods”, of a determined quantity Q(p) of aluminium trifluoride (AlF3) determined by the following equation: Q(p)=Qint(p)?Qc1(p)+Qt(p), where Qint(p) is an integral (or “self-adaptive”) term which represents the total actual AlF3 requirements of the cell and which is calculated from a mean Qm(p) of the actual AlF3 supplies made during the last N periods, Qc1 is a compensating term corresponding to the so-called “equivalent” quantity of AlF3 contained in the alumina added to the cell during the period p, and Qt(p) is a corrective term which is a typically increasing function of the difference between the measured bath temperature T(p) and the set-point temperature To.

Abstract: The invention relates to a regulation method for an electrolytic cell for the production of aluminium by means of reduction of alumina dissolved in a molten cryolite bath and comprises the addition, in the electrolyte bath, during pre-determined time intervals p referred to as “periods”, of a determined quantity Q(p) of aluminium trifluoride (AlF3) determined by the following equation: Q(p)=Qint(p)−Qc1(p)+Qt(p), where Qint(p) is an integral (or “self-adaptive”) term which represents the total actual AlF3 requirements of the cell and which is calculated from a mean Qm(p) of the actual AlF3 supplies made during the last N periods, Qc1 is a compensating term corresponding to the so-called “equivalent” quantity of AlF3 contained in the alumina added to the cell during the period p, and Qt(p) is a corrective term which is a typically increasing function of the difference between the measured bath temperature T(p) and the set-point temperature To.

Abstract: The invention relates to a regulation method for an electrolytic cell for the production of aluminium by means of reduction of alumina dissolved in a molten cryolite bath, wherein a solidified bath ridge is formed on the internal walls of the pot, a quantity B, referred to as the “ridge variation indicator”, which is sensitive to the variation of said solidified bath ridge, is determined and at least one of the setting means of the pot (such as the anode-metal distance) and/or at least one control operation (such as the addition of AlF3) is modified as a function of the value obtained for said indicator. The indicator may be determined from electrical measurements on the pot and/or from measurements of the liquid metal surface area. The method according to the invention makes it possible to regulate an electrolytic cell effectively at currents of up to 500 kA with an electrolyte bath with an AlF3 content greater than 11% and reduce the number of AlF3 content measurements in the bath considerably.

Abstract: A clutch mechanism, particularly for automatically operated automotive transmissions, for engaging shift ranges of continuously variable transmissions or step-by-step variable transmissions, and having at least two independently axially movable clutch rings with clutch profiles which cooperate with respective corresponding mating clutch rings clutch profiles, a clutch carrier mounted on a transmission element for rotation therewith in a fixed axial position, and having fluid actuated pressure pistons for shifting the movable clutch rings toward the mating rings. The clutch system can be disengaged under load and requires a small construction space. It can be produced at low cost and is almost free from drag losses. Clutch times and clutch travels are short. The shift pressures are very low. In addition, several clutches can be combined into a compact and relatively small clutch assembly.