U.S. patent application number 11/791423 was filed with the patent office on 2009-05-21 for current busbar.
Invention is credited to Stig Torvund.
Application Number | 20090127126 11/791423 |
Document ID | / |
Family ID | 34793442 |
Filed Date | 2009-05-21 |
United States Patent
Application |
20090127126 |
Kind Code |
A1 |
Torvund; Stig |
May 21, 2009 |
CURRENT BUSBAR
Abstract
Current busbar for anode or cathode for use in production of
aluminium from alumina in an electrolysis bath in an electrolysis
cell, comprising ends or sections that during operation shall be
within the electrode body are formed as horizontally oriented
conical bodies and cylindrical or conical grooves with largest
horizontal cross section dimension within said grooves, such that
by sliding in correspondingly formed cooper rails on the external
parts of the busbar, said bodies and rails are releasable
joined.
Inventors: |
Torvund; Stig; (Tolvsrod,
NO) |
Correspondence
Address: |
SENNIGER POWERS LLP
100 NORTH BROADWAY, 17TH FLOOR
ST LOUIS
MO
63102
US
|
Family ID: |
34793442 |
Appl. No.: |
11/791423 |
Filed: |
February 16, 2005 |
PCT Filed: |
February 16, 2005 |
PCT NO: |
PCT/NO2005/000056 |
371 Date: |
August 6, 2008 |
Current U.S.
Class: |
205/385 ;
205/380 |
Current CPC
Class: |
C25C 3/16 20130101 |
Class at
Publication: |
205/385 ;
205/380 |
International
Class: |
C25C 1/12 20060101
C25C001/12 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 20, 2004 |
NO |
20040762 |
Claims
1. Current busbar for anode or cathode for use in production of
aluminium from alumina in an electrolysis bath in an electrolysis
cell, which current busbar comprises one or more ends or sections
that during operation shall extend out of an electrode body, and
one or more ends or sections that during operation shall be within
the electrode body, wherein ends or sections that during operation
shall be within the electrode body are formed as one or more in
substance horizontally oriented conical bodies with largest
horizontal cross section diameter within the electrode body, such
that by sliding said bodies axially into one or more adapted
conical holes in the electrode body said bodies will be embedded
and kept into the electrode body, and said conical bodies or
elements connected thereto are manufactured from steel or steel
over a copper core, and are provided with one or more in substance
horizontally formed cylindrical or conical grooves with largest
horizontal cross section dimension within said grooves, such that
by sliding in correspondingly formed copper rails on the external
parts of the busbar, said bodies and rails are releasably
joined.
2. Current busbar according to claim 1, wherein the cross section
of the parts that are to be within the electrode body have form as
a circle, triangle or quadrangle under or over a high and narrow
rectangle, such that the largest horizontal dimension of the
circle, triangle or quadrangle is at least four times larger than
the horizontal dimension of the rectangle.
3. Current busbar for anode or cathode for use in production of
aluminium from alumina in an electrolysis bath in an electrolysis
cell, which current busbar comprises one or more ends or sections
that during operation shall extend out of an electrode body, and
one or more ends or sections that during operation shall be within
the electrode body, wherein ends or sections that during operation
shall be within the electrode body are formed as one or more in
substance horizontally oriented conical bodies with largest
horizontal cross section diameter within the electrode body, such
that by sliding said bodies axially into one or more adapted
conical holes in the electrode body said bodies will be embedded
and kept into the electrode body.
4. Current busbar for anode or cathode for use in production of
aluminium from alumina in an electrolysis bath in an electrolysis
cell, which current busbar comprises one or more ends or sections
that during operation shall extend out of an electrode body, and
one or more ends or sections that during operation shall be within
the electrode body, wherein the transfer between steel in parts of
the current busbar that are to be within or close to the electrode
body and copper in external parts from the electrode body are
formed as one or more in substance horizontally formed cylindrical
or conical grooves in the steel with largest horizontal cross
section dimension within said grooves, and correspondingly formed
copper rails on the external parts of the current busbar, such that
by sliding in the copper rails into the steel grooves the parts
will be releasably joined.
5. Current busbar according to claim 1, wherein the current busbar
is an anode hanger.
6. Current busbar according to claim 1, wherein the current busbar
is a cathode steel.
7. Current busbars according to claim 1, wherein pure aluminium,
aluminium alloy, copper or copper alloy is used as construction
material in the parts furthest away from the electrode body and in
a distance close to or within the electrode body, with a protective
lining of steel for parts within or close to the electrode
body.
8. Electrode body, consisting of carbon and is provided with
adapted grooves for mounting of current busbars according to claim
1.
9. Electrode body according to claim 8, wherein the conical grooves
in the electrode body is slightly longer than the conical bodies,
such that said conical bodies will fit into said conical grooves
even though they have been slightly worn-out.
10. Electrode, comprising current busbars according to claim 1
joined with electrode body according to claim 8.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to current bus bars for anodes
or cathodes for use in production of aluminium by electrolysis of
alumina in an electrolysis bath in an electrolysis cell.
BACKGROUND OF THE INVENTION
[0002] Production of primary aluminium takes place by electrolysis
of alumina solved in a melted halogenide electrolysis bath, for
example an electrolysis bath comprising cryolite. By electrolysis,
compositions that are split into ions in the electrolyte are
reduced at the cathode and oxidized at the anode, by use of
impressed current. Thereby aluminium can be produced at the cathode
and oxygen at the anode. The process used for production of
aluminium, the Hall-Heroult-process, was developed almost
simultaneously and independent by the American Hall and the
Frenchman Heroult for more than one hundred years ago. For both the
anode and the cathode it is most common to use an electrode body of
carbon, with one or more current busbars embedded within the
carbon. The function of the current busbars are to deliver current
to or from the electrode body, to conduct heat away from the
electrolysis bath, and to contribute to the mechanical strength and
connection. The current busbars are connected directly or via
further means to an outer current circuit.
[0003] In patent publication WO 02/42525 various embodiments of
current busbars for anodes and cathodes are illustrated, with
associated description of essential features for current
busbars.
[0004] Despite many years of development a demand still exists for
improvement of the electrolysis cell, including the current
busbars. Particularly a demand exists for current busbars having
large heat conduction away from the electrolysis bath. Further, it
would be preferable with current busbars with reduced voltage drop,
which inter alia is related to the contact area towards the carbon.
Further, it would be beneficial with current busbars that, with
regard to the anodes, do not require casting to the carbon via a
cast iron lining or -socket formed by liquid cast iron being poured
into the gap between adapted holes in the electrode body and
inserted anode nipples, which is made possible by the holes in the
electrode body having slightly larger diameter than the nipples.
Accordingly, a demand exists for avoiding the use of a cast iron
lining for fastening the current busbars to the carbon, whereby the
current busbars can be improved with respect to mounting and
demounting to the carbon. A demand also exists for joining embedded
parts or sections of current busbars to the further parts of the
current busbars, in a simple and releasable way, with good
electrical, thermal and mechanical contact.
SUMMARY OF THE INVENTION
[0005] With the present invention the above-mentioned demands are
met, by providing a novel type of current busbar for anode or
cathode for use in production of aluminium from alumina in an
electrolysis bath in an electrolysis cell, which current busbar
comprises one or more ends or sections that during operation shall
extend out of an electrode body, and one or more ends or sections
that during operation shall be embedded or within the electrode
body. The current busbar is distinguished by comprising both or one
of the features as follows:
[0006] ends or sections that during operation shall be within the
electrode body are formed as one or more in substance horizontally
oriented conical bodies with largest horizontal cross section
diameter within the electrode body, such that by sliding said
bodies axially into one or more adapted conical holes in the
electrode body said bodies will be embedded and kept into the
electrode body, and
[0007] said conical bodies or elements connected thereto are
manufactured from steel or steel over a copper core, and are
provided with one or more in substance horizontally formed
cylindrical or conical grooves with largest horizontal cross
section dimension within said grooves, such that by sliding in
correspondingly formed copper rails on the external parts of the
busbar, said bodies and rails are releasably joined.
[0008] With in substance horizontally oriented means in substance
parallel with the electrolysis bath or horizontal with few degrees
deviation, most preferable completely horizontal.
[0009] With conical body it is meant an elongated body having
increasing or decreasing cross section dimensions over a
substantial part of its length, preferably the full length. The
corresponding is true for conical holes. With a cylindrical groove
or body it is meant an even cross section over a substantial part
of the length, preferably all the length except from optional
tapering or grounding off at the ends. Cylindrical does not
necessarily mean round cross section, the only requirement is that
the cross section is the same along the length. The cross section
therefore can be triangular, four-sided, five-sided, round,
elliptical, T-formed or take any other form, which also is true for
conical bodies, provided that the further distinguishing features
are maintained. It is also important to be aware of that the
cylindrical body can extend in vertical direction, such that a part
of the cylinder body, along the full or parts of its length, can
extend out for example from the electrode body.
[0010] The feature of the largest horizontal cross section
dimension of the conical body and cylindrical body to be within
respectively the electrode body and the groove when these are
joined, hinder that bodies as joined can be separated from each
other by pulling in vertical direction, orthogonal to the
longitudinal axis of the conical body and cylindrical body. For
joining into the electrode body it is not required with cast iron
lining, ramming paste, ramming mass or glue, which provides savings
both with respect to materials and labour. The conical form ensures
good thermal, electrical and mechanical contact even after
beginning of wearing out the conical bodies. A copper rail within a
steel groove will during operation have very good electrical
thermal and mechanical contact because the copper has larger
thermal expansion than the steel, such that an appropriate
tolerance for joining at room temperature, for example 0.15-0.5 mm
clearance, will be filled out by expansion of the copper. Thereby a
releasable joining is achieved with good electrical, thermal and
mechanical contact, which provides savings with respect to labour
and possibility for easy replacement of parts of a current
busbar.
[0011] It is preferable if the cross section of the parts that are
to be built into the electrode body has form of a circle, triangle
or quadrangle under or below a high and narrow rectangle, such that
the largest horizontal dimension of the circle, triangle or
quadrangle is at least four times larger than the horizontal
dimension of the rectangle. This results in simple and solid
fastening.
[0012] The current busbar according to the invention is preferably
formed such that different materials in the longitudinal direction
of the busbar are welded together by linear friction welding,
surfacing friction welding, rotation friction welding, induction
welding, laser welding or electron beam welding, because of good
electrical, thermal and mechanical contact.
[0013] The current busbar according to the invention can preferably
be manufactured with pure aluminium, aluminium alloy, copper or
copper alloy used as construction material in the parts furthest
away from the electrode body and in a distance close to or within
the electrode body, with a protective lining of steel for parts
within or close to the electrode body. Thereby the heat conduction
is maximized while the electrical resistance is minimized and the
electrolysis cell can be operated at high amperage.
[0014] The current busbar according to the invention is preferably
either an anode hanger or a cathode steel. The current busbars
according to the invention is preferably surface treated with
wolfram, for increased life. The embodiment of the current busbar
with only the distinguishing feature with the copper rails, can
include traditional nipples as the ends or sections that during
operation are within the electrode body.
[0015] With the present invention also an electrode body is
provided, distinguished in that it in substance consists of carbon
and has adapted grooves for mounting of the current busbars
according to the present invention. The conical holes in the
electrode body are preferably slightly longer than the conical
bodies, such that said conical bodies will fit into said conical
holes even after some wearing out.
[0016] With the present invention also an electrode is provided,
distinguished in that it comprises current busbars according to the
present invention joined with electrode body according to the
present invention.
DRAWINGS
[0017] The invention is further illustrated by drawings, of
which:
[0018] The FIGS. 1a and 1b illustrate an anode hanger according to
the present invention.
[0019] FIG. 2 illustrates another embodiment of an anode hanger
according to the present invention.
[0020] FIG. 3 illustrates a third embodiment of an anode hanger
according to the present invention.
DETAILED DESCRIPTION
[0021] First, reference is made to the FIGS. 1A and 1B, which
illustrate an anode hanger according to the present invention,
viewed orthogonal to the conical body 1, for FIG. 1A, and along the
longitudinal axis of the conical body, for FIG. 1B, respectively.
The conical body is joined with an electrode body 2 by being slided
into a conical groove 3 with form corresponding to the conical
body. As apparent from the figure the largest horizontal cross
section dimension for the conical body is within the electrode
body, such that the conical body as joined with the electrode body
during operation is fastened and kept in place into the electrode
body. The conical body is on the upper side fastened into a
narrower element, with cross section form as a rectangle with far
smaller horizontal dimension than the conical body, such that even
though the groove in the electrode body is upwardly open along all
or parts of the length of the conical body, said conical body
cannot escape from the electrode body during operation. In the
illustrated embodiment an inner core of copper 4 is provided in the
conical body, the rectangle and an above positioned connecting
beam. Outside the copper is a steel lining 5. The upper part of the
anode hanger is formed by an aluminium part 6, joined with the
copper by friction welding. In the illustrated embodiment of the
current busbar, in form of an anode hanger, copper and aluminium is
used in a large extent, which is preferable with respect to thermal
and electrical conductivity. The whole anode hanger could be
prepared by steel, but out of consideration to thermal and
electrical conductivity preferably copper and optionally aluminium
are used extensively. For increased heat conduction cooling ribs
can be provided in addition to using increased dimension for the
different parts of the anode hanger.
[0022] Reference is further made to FIG. 2 that illustrates another
embodiment of an anode hanger according to the invention, more
specifically an anode hanger where a copper rail 7 is arranged to
be slided into a correspondingly formed groove in a cylindrical
steel body 8 that is to be embedded into the electrode body. The
copper rail and the groove are formed with tolerances such that the
copper rail relatively easy can be slided into the groove in the
steel body at room temperature. By heating during operation in the
cell copper will expand more than steel such that a good
electrical, thermal and mechanical connection between the copper
and the steel is achieved.
[0023] Reference is made to FIG. 3 where a further embodiment of an
anode hanger according to the invention is illustrated, more
specifically a steel nipple 9 with groove for sliding in of a
copper rail 7 is illustrated. A number of steel nipples can be
passed into the copper rail 7.
[0024] Regarding the anode hangers illustrated on FIGS. 2 and 3,
the cylindrical steel body 8 and steel nipples 9 could be replaced
with respect to a conical body of massive steel or with steel
lining around a copper core, with grooves for fastening of the
copper rail, with the groove either directly into the conical body
or above, for example in a connecting beam. The most preferred
embodiment of the invention (not illustrated) comprises both a
conical body and fastening to the above part of the anode hanger by
use of a copper rail, because said embodiment includes all the
advantages of the invention.
EXAMPLE
[0025] An anode hanger with a conical section embedded into the
electrode body illustrates some of the advantages of the invention.
The cylinder section has length 1.5 m and consists of a 100 to 140
mm diameter bolt under a small, high rectangle where in total 100
mm vertical rectangle side is embedded into electrode body. The
resulting contact area with the electrode body is about 726 500
mm.sup.2. A standard anode hanger with 4 nipples has a contact area
of typical 281 000 mm.sup.2. The contact area has thereby increased
2.59 times. By having an adapted cross section area, choice of
materials and form of the ends or sections of the current busbar
that during operation shall extend out from the electrode body,
very preferable properties can be achieved with respect to the
demands that are met with the present invention
* * * * *