Norsk Hydro, A.s.

Norskhydro Asa

Bernt Nagell

Gisle G Enstad

Kjell Magne Dalen

Morten Karlsen

Leiv B Ognedal

Knut A Paulsen

Alfred Kvalavag

Bjorn Vikshaland

A method and a system distribute fluidizable materials from a reservoir of materials to one or more material receiving units. The distribution system has at least two hydraulic levels between the reservoir and the material receiving units. The system further includes a fluidizing element with good dynamic response properties. The system can be used for distribution of alumina and/or fluoride to feeding equipment in electrolysis cells with a reduced consumption of fluidizing gas.

Method and a system of distribution of fluidizable materials

A pneumatic metering device for metering powdered materials, for example in connection with feeding aluminum oxide and aluminum fluoride to an electrolysis cell for production of aluminum, includes a container in the form of a relatively long, closed channel or similar structure. A fluidizing element is fitted in the base of the channel for supply of air for fluidization of material which is located in the channel. The container is fitted with an inlet for feeding material to the container from a store in the form of a silo or similar and an outlet for metered discharge of material from the container. The area below the inlet is inactive and is not supplied with fluidizing air, whereas air is supplied intermittently to the fluidizing element which is designed to cover essentially all other parts of the base of the channel.

Pulse-controlled metering device

An apparatus having a closed channel or container for transporting and/or distributing fluidizable material includes an air- or gas-permeable wall arranged in the channel and forming a partition between an upper pathway for the fluidizable material and a lower flue to which is fed fluidizing gas from a gas source via a tube. An inlet is provided for feeding fluidizable material to the channel. The apparatus also includes one or more outlets for continual or intermittent run off of material from the channel, and a tube for ventilating the channel. The channel is equipped at its inlet with pipe stub extending into the upper pathway. An area defined under the pipe stub is inactive or is equipped with a separately arranged fluidizing wall with a separate gas feed.

Apparatus for automatic level control in a closed channel or container

In a feeder for feeding additives such as aluminium oxide or fluoride to aluminium electrolysis cells, the additives are fed to the electrolytic bath of the cell through a hole in the bath crust via a pipe stub. The hole is made by means of a crust breaker having a crow bar connected to a piston/cylinder device. The point feeder is made of a housing comprising an upper part, wholly or partly open to the surroundings, and a lower part closed the crust and other parts of the surroundings. The crow bar extends down through a guide in the form of a bushing, which is provided between the upper and lower part. Further, the pipe is attached to the lower part, or is provided under the lower part, for instance on the gas apron of the anode casing in a Soederberg cell.

Point feeder for aluminium electrolysis cell

A pneumatic dosimeter for providing exact dosage of pulverulent materials, for instance for supplying aluminium oxide and fluoride to an aluminium electrolytic cell, comprises a vessel (1) with an upper chamber (2) which at the bottom is provided with a fluidizing device in the form of a fluidizing canvas (3) with an underlying chamber which is connected to an air source via a pipe line (5). The vessel is provided with an inlet (6) for the supply of pulverulent material from a supply tank or hopper (7) to the upper chamber (2), and an outlet opening for discharging the chamber (2). At least one fluidizing channel or pipe (9) is provided between the supply tank (7) and the vessel (1). This channel is provided with a fluidizing wall or fluidizing canvas (10) which is connected to an air supply source through a pipe line (12). The filling and emptying of the chamber (2) is carried out by solenoid valves (13,14) which are provided in the pipe line (5 ) connected to the vessel (1) and the pipe line (12) connected to the channel (9), respectively. The solenoid valves are controlled by a PLS governor or a processor such that air is supplied to the channel (9) and the vessel (1) according to a preferred time and frequency program.

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Haugesund, Norway

Bernt Nagell