U.S. patent application number 10/089930 was filed with the patent office on 2002-12-12 for refractory components.
Invention is credited to Vincent, Mark.
Application Number | 20020185794 10/089930 |
Document ID | / |
Family ID | 9896931 |
Filed Date | 2002-12-12 |
United States Patent
Application |
20020185794 |
Kind Code |
A1 |
Vincent, Mark |
December 12, 2002 |
Refractory components
Abstract
A refractory component is provided for use in a metal producing
or refining process in which the component is at least partially
immersed in molten metal. The component including a graphite member
(2) and a refractory sleeve (10) that covers at least part of the
graphite member. A recess (12) is provided in the surface of the
graphite member (2) and the refractory sleeve (10) is located in
the recess.
Inventors: |
Vincent, Mark; (Leighton
Buzzard, GB) |
Correspondence
Address: |
James W Mckee
Fay Sharpe Fagan Minnich & McKee
1100 Superior Avenue 7th Floor
Cleveland
OH
44114-2518
US
|
Family ID: |
9896931 |
Appl. No.: |
10/089930 |
Filed: |
April 3, 2002 |
PCT Filed: |
January 29, 2001 |
PCT NO: |
PCT/GB01/00347 |
Current U.S.
Class: |
266/280 |
Current CPC
Class: |
C04B 2235/95 20130101;
C04B 35/522 20130101; C21B 2100/22 20170501; C04B 2235/9676
20130101; C04B 2235/94 20130101 |
Class at
Publication: |
266/280 |
International
Class: |
C21B 007/06 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 4, 2000 |
GB |
0019088.4 |
Claims
1. A refractory component for use in a metal producing or refining
process in which the component is at least partially immersed in
molten metal, the component including a graphite member and a
refractory sleeve that covers at least part of the graphite member,
characterised in that a recess is provided in the surface of the
graphite member and the refractory sleeve is located in the
recess.
2. A refractory component according to claim 1, characterised in
that the refractory sleeve covers the region of the graphite member
that in use passes through the surface of the molten metal.
3. A refractory component according to claim 2, characterised in
that the refractory sleeve is of a length such that, in use, it
extends above and below the surface of the molten metal by a
distance in the range 50-300 mm, preferably 100-150 mm.
4. A refractory component according to any one of the preceding
claims, characterised in that the refractory sleeve is cast in situ
in the recess provided in the surface of the graphite member.
5. A refractory component according to any one of the preceding
claims, characterised in that the external surface of the
refractory sleeve is substantially level with the external surface
of the graphite member.
6. A refractory component according to claim 5, characterised in
that the recess has a depth in the range 1-30 mm, preferably 8
mm.
7. A refractory component according to any one of claims 1 to 4,
characterised in that the external surface of the refractory sleeve
is raised above the external surface of the graphite member.
8. A refractory component according to claim 7, characterised in
that the recess has a depth in the range 1-30 mm. preferably 3
mm.
9. A refractory component according to any one of the preceding
claims, characterised in that the recess has circumferential walls
that are inclined towards one another.
10. A refractory component according to claim 9, characterised in
that the circumferential walls that are inclined relative to the
surface of the graphite member at an angle in the range
20-89.degree., preferably approximately 60.degree..
11. A refractory component according to any one of the preceding
claims, characterised in that the sleeve has a thickness in the
range 1-25 mm, preferably 7 mm.
12. A refractory component according to any one of the preceding
claims, including an expansion gasket between the refractory sleeve
and the graphite member.
13. A refractory component according to claim 12, characterised in
that the expansion gasket has a thickness in the range 0.5-5 mm,
preferably 1 mm.
14. A refractory component according to claim 12 or claim 13,
characterised in that the expansion gasket includes a layer of
ceramic paper.
15. A refractory component according to any one of the preceding
claims, in which the refractory sleeve is made of a ceramic
material.
16. A refractory component according to claim 15, in which the
refractory sleeve is made off used silica, alumina, silicon
carbide, silicon nitride, silicon aluminium oxy-nitride, Mullite,
zircon or zirconia, or a combination thereof.
17. A refractory component according to any one of the preceding
claims, wherein the component comprises a substantially cylindrical
shaft.
18. A refractory component according to claim 17, in which the
shaft has a diameter in the range 30-200 mm, preferably
approximately 75 mm.
19. A refractory component according to claim 17 or claim 18, in
which the shaft has a length in the range 0.5-2.0 m, preferably
approximately 1.0-1.3 m.
20. A refractory component according to any one of claims 17 to 19,
in which the shaft is hollow.
21. A refractory component according to any one of the preceding
claims, for use in a process for producing or refining non-ferrous
metals.
22. A refractory component according to claim 21, for use in a
process for producing or refining aluminium and aluminium
alloys.
23. A method of making a refractory component for use in a metal
producing or refining process in which the component is at least
partially immersed in molten metal, the refractory component
including a graphite member and a refractory sleeve that covers at
least part of the graphite member, characterised in that a recess
is formed in the surface of the graphite member and the refractory
sleeve is cast in the recess.
24. A method according to claim 23, in which the refractory sleeve
is cast in situ in the recess.
25. A method according to claim 23 or claim 24, in which the
graphite member is shaped on a lathe, and the recess is formed on
the surface of the graphite member during the shaping
operation.
26. A method according to any one of claims 23 to 25, in which a
mould is placed over the recess and a refractory material is
injected into the recess beneath the mould.
27. A method according to any one of claims 23 to 26, in which the
refractory sleeve is fired on the graphite member.
Description
[0001] The present invention relates to refractory components for
use in a metal producing or refining process in which the
components are at least partially immersed in molten metal. In
particular but not exclusively the invention relates to a graphite
shaft for use in a process for producing or refining non-ferrous
metals, such as aluminium and aluminium alloys. The invention also
relates to a method of making such refractory components.
[0002] Graphite shafts are used for various purposes in processes
for producing and refining non-ferrous metals including aluminium
and aluminium alloys, where the shaft is at least partially
immersed in the molten metal (the "melt").
[0003] Liquid aluminium, aluminium alloys and other non-ferrous
metals contain inclusions, dissolved hydrogen and alkali metal
impurities. These are undesirable as they adversely affect the
physical properties of the metals.
[0004] Various methods are conventionally used to remove such
impurities, one such method being rotary degassing. In this
process, inert gas is injected into the liquid metal through a
hollow graphite shaft, one end of which is immersed in the liquid
metal, well below the surface. A rotor may be fixed to the end of
the shaft, and the whole assembly is rotated, typically at 200-700
RPM. This increases the efficiency of the process. The spinning
action of the rotor breaks up the gas stream emerging from the
shaft into fine bubbles, increasing the surface area of the gas.
The gas then rises through the metal, removing dissolved hydrogen
and inclusions and carrying them to the surface of the melt.
[0005] Additionally, chlorine can be added to the inert gas and
injected through the shaft and rotor into the metal. The chlorine
reacts with alkali metals in the metal and the resulting liquid
impurity is removed by the bubbles. This chlorine may be added as a
gas, or injected as a solid (in powdered or granulated form) or a
liquid salt mixture.
[0006] In some cases, the rotor acts as a stirrer, or is replaced
by a stirrer, and the chlorine can then be added in a solid salt
form to the surface of the metal, and is mixed into the metal by
the stirring action.
[0007] A flux may also be added, usually in the form of solid or
liquid salts, for example NaCl, K2Cl3, MgCl etc.
[0008] Graphite is used for these shafts because it is resistant to
thermal shock, is not wetted by liquid aluminium, has low thermal
expansion, is mechanically strong and tough even at elevated
temperatures, is easy to machine and does not react with the liquid
aluminium. However, it is well known that graphite oxidises at
elevated temperatures. The shafts therefore gradually erode,
particularly in the region where the shaft passes through the
surface of the liquid metal, and have to be replaced
periodically.
[0009] Many methods exist for treating the graphite to reduce the
rate of oxidation. Typically, the graphite used in these
applications is treated by impregnating protective compounds into
its surface. This allows it to be used for extended times in
liquid, non-ferrous metals. However, the failure mechanism of these
shafts is still usually due to erosion and oxidation of the
graphite at the metal line.
[0010] To avoid this problem, some suppliers have tried to produce
these parts in ceramic materials such as fused silica, alumina,
silicon carbide, silicon nitride, silicon aluminium oxy-nitride,
Mullite, zircon, zirconia and combinations thereof. However,
despite being harder (and therefore more abrasion resistant) and
resistant to oxidation, these materials are usually lower in
strength, more brittle and more expensive to manufacture than
graphite. This causes problems when connecting the ceramic parts to
the machines, which is normally done with a screw thread. It also
causes premature breakage due to impact from cleaning tools or
foreign objects in the metal. The net result is that there is not a
significant increase in the lifetime of the ceramic part compared
to the graphite part.
[0011] It is also known to apply a ceramic surface to the graphite,
in the area of attack (i.e. along the metal line). Many systems
have been tried, including the use of ceramic coatings (applied by
being sprayed, brushed, dipped etc), fibre and ceramic bandages,
vacuum formed sleeves, and preformed cast sleeves loosely mounted
on the shaft. Whilst some of these improve the lifetime of the
shaft, there is not generally a large enough improvement to justify
the additional cost of treatment. An improved method of treatment
is therefore required.
[0012] Graphite components (including hollow and solid shafts) are
also used for other purposes in processes for producing and
refining non-ferrous and ferrous metals. For example, in the
production of non-ferrous metals these components may be used for
removing hydrogen by injecting gases such as nitrogen or argon, for
removing inclusions and alkali metals by injecting reactive gases
such as chlorine or solid or liquid chlorine salt fluxes, or as
part of a stirring assembly to aid mixing of the metal, by driving
a rotor or stirrer. In the production of ferrous metals, graphite
may be used for components such as submerged entry nozzles,
injection lances and flow control systems, for injecting gases
under the surface of the metal or controlling the flow of the
metal.
[0013] It is an object of the present invention to provide a
graphite component for use in a metal producing or refining
process, that mitigates at least some of the aforesaid problems. A
further object of the present invention is to provide a method of
making such a graphite component.
[0014] According to the present invention there is provided a
refractory component for use in a metal producing or refining
process in which the component is at least partially immersed in
molten metal, the component including a graphite member and a
refractory sleeve that covers at least part of the graphite member,
characterised in that a recess is provided in the surface of the
graphite member and the refractory sleeve is located in the
recess.
[0015] The refractory sleeve protects the covered part of the
graphite member from oxidation and erosion. Because the sleeve is
located in the recess, it is mechanically fixed very securely to
the graphite shaft, preventing liquid metal from penetrating
between the sleeve and the graphite. The arrangement is also very
strong, but does not affect the overall dimensions of the
component.
[0016] Advantageously, the refractory sleeve covers the region of
the graphite member that in use passes through the surface of the
molten metal, thereby protecting the graphite member in that most
vulnerable region. Preferably, the refractory sleeve is of a length
such that, in use, it extends above and below the surface of the
molten metal by a distance in the range 50-300 mm, preferably
100-150 mm. This ensures that the component is protected, even if
the level of the liquid metal varies significantly.
[0017] Advantageously, the refractory sleeve is cast in situ in the
recess provided in the surface of the graphite member, so ensuring
a good fit. Advantageously, the external surface of the refractory
sleeve is substantially level with the external surface of the
graphite member, to avoid causing turbulence. Alternatively, the
external surface of refractory sleeve may stand above the external
surface of the graphite member. This allows the depth of the recess
in the graphite member to be reduced without reducing the thickness
of the sleeve, and is the preferred arrangement where a deep recess
would compromise the strength of the graphite member.
[0018] The recess may have a depth in the range 1-30 mm, preferably
8 mm. Preferably, the recess has circumferential walls that are
inclined towards one another. The circumferential walls may be
inclined relative to the surface of the graphite member at an angle
in the range 20-89.degree., preferably approximately 60.degree..
This locks the sleeve into the recess. The sleeve may have a
thickness in the range 1-25 mm, preferably about 7 mm.
[0019] Advantageously, the refractory component includes an
expansion gasket between the refractory sleeve and the graphite
member, to accommodate differential thermal expansion of the two
components. The expansion gasket may have a thickness in the range
0.5-5 mm, preferably 1 mm. The expansion gasket may include a layer
of ceramic paper.
[0020] Advantageously, the refractory sleeve is made of a ceramic
material, which may be fused silica, alumina, silicon carbide,
silicon nitride, silicon aluminium oxy-nitride, Mullite, zircon or
zirconia, or a combination thereof.
[0021] Advantageously, the refractory component comprises a
substantially cylindrical shaft, which may have a diameter in the
range 3 0-200 mm, preferably approximately 75 mm, and a length in
the range 0.5-2.0m, preferably approximately 1.0-1.3 m.
Advantageously, the shaft is hollow.
[0022] Advantageously, the refractory component is suitable for use
in a process for producing or refining non-ferrous metals, in
particular aluminium and aluminium alloys.
[0023] According to another aspect of the invention there is
provided a method of making a refractory component for use in a
metal producing or refining process in which the component is at
least partially immersed in molten metal, the refractory component
including a graphite member and a refractory sleeve that covers at
least part of the graphite member, characterised in that a recess
is formed in the surface of the graphite member and the refractory
sleeve is cast in the recess.
[0024] Advantageously, the refractory sleeve is cast in situ in the
recess.
[0025] Preferably, the graphite member is shaped on a lathe, and
the recess is formed on the surface of the graphite member during
the shaping operation.
[0026] Advantageously, a mould is placed over the recess and a
refractory material is injected into the recess beneath the
mould.
[0027] Advantageously, the refractory sleeve is fired on the
graphite member.
[0028] Embodiments of the invention will now be described, by way
of example, with reference to the accompanying drawings, in
which:
[0029] FIG. 1 is an isometric drawing of a refractory component
according to a first embodiment of the invention, comprising a
graphite shaft with a ceramic sleeve, showing some hidden
details;
[0030] FIG. 2 is a side view of the component, showing the level of
the liquid metal during use;
[0031] FIG. 3 is a side section through the component on line A-A
of FIG. 2;
[0032] FIG. 4 is a sectional side view at a larger scale, showing
part of the component shown in FIG. 3;
[0033] FIG. 5 is an isometric drawing of a refractory component
according to a second embodiment of the invention, comprising a
graphite shaft with a ceramic sleeve, showing some hidden
details;
[0034] FIG. 6 is a side view of the component shown in FIG. 5,
showing the level of the liquid metal during use;
[0035] FIG. 7 is a side section through the component on line A-A
of FIG. 5;
[0036] FIG. 8 is a sectional side view at a larger scale, showing
part of the component shown in FIG. 7;
[0037] FIG. 9 is a plan view of a refractory component according to
a third embodiment of the invention, comprising a pump block,
showing some hidden details;
[0038] FIG. 10 is a side section through the component on line B-B
of FIG. 9;
[0039] FIG. 11 is a sectional side view at a larger scale, showing
part of the component shown in FIG. 10;
[0040] FIGS. 12 and 13 are plan views of the component, not showing
any hidden details;
[0041] FIG. 14 is an end section on line A-A of FIG. 13, and
[0042] FIG. 15 in an isometric view of the component, partially
broken away.
[0043] The refractory component shown in FIGS. 1-4 comprises a
substantially cylindrical shaft 2 of solid graphite, having a
length of approximately 1 m and a diameter of approximately 75 mm.
At the lower end of the shaft 2 there is a portion 4 of reduced
diameter that is provided with a screw thread 6 for fixing the
shaft to a rotor. A threaded bore 8 is provided at the upper end of
the shaft for fixing the shaft to a rotary drive mechanism.
[0044] A sleeve 10 of ceramic material is located in a recess 12
provided approximately in the middle of the shaft 2. The sleeve 10
covers the portion of the shaft that in use extends through the
surface 14 of the liquid metal.
[0045] The recess 12 comprises a shallow slot having a depth of
about 8 mm and a width of about 250 mm, which extends around the
circumference of the cylindrical shaft 2. The circumferential walls
16 that define the upper and lower edges of the recess 12 are
inclined towards one another, at an angle of about 60.degree. to
the external cylindrical surface of the graphite shaft.
[0046] The sleeve 10 is made of a ceramic material, for example
fused silica, alumina, silicon carbide, silicon nitride, silicon
aluminium oxy-nitride, Mullite, zircon or zirconia, or a
combination thereof. It is formed by injecting the material in
liquid or semi-solid form into the recess 12 then allowing it to
cure. The sleeve therefore essentially fills the recess and takes
on its shape. The upper and lower edges 18 of the sleeve 10 are
therefore inclined outwards, mechanically locking the sleeve 10 to
the shaft 2.
[0047] The sleeve 12 has a thickness of about 7 mm, leaving a 1 mm
gap 20 between the sleeve 12 and the shaft 2, which in use
accommodates differential thermal expansion of the sleeve and the
shaft. The gap 20 may be filled with an expansion gasket, for
example a sheet of ceramic paper.
[0048] The refractory component may of course have different
dimensions, according to the purpose for which it is intended.
Typically, however, the ranges for those dimensions will be
approximately as follows:
1 Preferred Dimension value Range A Angle of recess walls
60.degree. 20.degree.-89.degree. B Expansion gap 1 mm 0.5-5 mm C
Thickness of sleeve 7 mm 1-25 mm D Length of sleeve below metal
level 150 mm 50-300 mm E Length of sleeve above metal level 100 mm
50-300 mm F Diameter of shaft 75 mm 30-200 mm Length of shaft 1.3 m
0.5-2 m
[0049] The refractory component may also take the form of a hollow
shaft, for injecting gas into the liquid metal as part of a rotary
degassing operation, similar principles of construction may be
employed in other refractory components made substantially of
graphite that come into contact with liquid metal (ferrous and
non-ferrous).
[0050] The shaft 2 shown in the accompanying drawing may be made as
follows:
[0051] 1. The graphite shaft 2 is shaped by machining a billet of
solid graphite on a lathe. The cylindrical surface of the shaft,
the reduced diameter end portion 4 and the recess 12 are all formed
during this shaping operation.
[0052] 2. A surface treatment may be applied to the graphite, to
reduce the rate of oxidation, for example, the graphite may be
treated by impregnating protective compounds into its surface. This
step is conventional and will not be described in detail.
[0053] 3. A mould slipped onto the shaft, covering the recess 12.
This mould may, for example, consist of a slotted cylindrical nylon
sleeve having an inside diameter matched to the outer diameter of
the graphite shaft 2, and a length about 100 mm longer than the
recess 12, to provide a 50 mm overlap at each end.
[0054] 4. The ceramic material is injected in liquid form through
the slot in the sleeve, until it completely fills the recess 10.
After allowing the ceramic to become solid or semi-solid, any
excess ceramic material is removed from the slot using a simple
scraper tool.
[0055] 5. When the ceramic has cured completely, the mould is
rotated then removed, and final smoothing may be undertaken with a
diamond file to ensure that the edges of the sleeve 10 are smooth
and flush with the external cylindrical surface of the graphite
shaft 2.
[0056] 6. The ceramic is kept damp for about 48 hours, for example
by wrapping in wet rags or spraying with water, to prevent it
cracking, and it is then allowed to dry.
[0057] 7. Finally, the ceramic material is fired on the graphite
shaft in a kiln at a temperature of about 380.degree. C., to drive
out any water remaining in the ceramic.
[0058] In use, the shaft 2 is mounted so that the ceramic sleeve 10
covers the part of the graphite shaft that passes through the
surface 14 of the liquid metal. The sleeve 10 prevents oxidation of
the graphite and protects the shaft from erosion and abrasion. The
useful lifetime of the component is therefore considerably
increased.
[0059] The advantages provided by the invention include the
following:
[0060] Reduced oxidation of the graphite shaft at the metal
line.
[0061] Substantially unaffected strength of the graphite.
[0062] Increased toughness and impact resistance of the graphite
part.
[0063] Easy machining of threads into the graphite.
[0064] The original dimensions of the shaft are retained (therefore
there is no change in the shaft's angular velocity at the metal
line, which can cause turbulence).
[0065] The `balance` of the shaft is unaffected (which is important
when spinning quickly).
[0066] Ingress of aluminium behind the refractory protective layer
is minimised.
[0067] The component is reliable and inexpensive to
manufacture.
[0068] The refractory component shown in FIGS. 5-8 is substantially
similar in many respects to the component shown in FIGS. 1-4 and
where appropriate similar reference numbers have been used. The
component comprises a substantially cylindrical shaft 2 of solid
graphite, having a diameter of approximately 40 mm. The shaft is
therefore considerably narrower than that shown in FIGS. 1-4. At
the lower end of the shaft 2 there is a portion 4 of reduced
diameter that is provided with a screw thread 6 for fixing the
shaft to a rotor. A threaded bore 8 is provided at the upper end of
the shaft for fixing the shaft to a rotary drive mechanism.
[0069] A sleeve 10 of ceramic material is located in a recess 12
provided approximately in the middle of the shaft 2. The sleeve 10
covers the portion of the shaft that in use extends through the
surface 14 of the liquid metal.
[0070] The recess 12 comprises a shallow slot having a depth of
about 3 mm and a width of about 250 mm, which extends around the
circumference of the cylindrical shaft 2. The recess is therefore
much shallower than that on the shaft shown in FIGS. 1-4, to avoid
compromising the strength of the shaft. The circumferential walls
16 that define the upper and lower edges of the recess 12 are
inclined towards one another, at an angle of about 60.degree. to
the external cylindrical surface of the graphite shaft.
[0071] The sleeve 10 is made of a ceramic material as described
above and is formed by placing a mould over the recess and
injecting the material in liquid or semi-solid form into the void
formed by the recess 12 and the mould. The sleeve therefore
essentially fills the recess and takes on its shape. The upper and
lower edges 18 of the sleeve 10 are therefore inclined outwards,
mechanically locking the sleeve 10 to the shaft 2.
[0072] The mould is shaped such that the outside diameter of the
sleeve is greater than the outside diameter of the shaft. The
external surface 22 of the sleeve therefore stands proud of the
external surface of the shaft. This allows the sleeve to retain a
thickness of about 7 mm, which it needs for strength, although only
2-3 mm of that thickness lies under the surface of the shaft.
[0073] As in the previous embodiment, a gap 20 is provided between
the sleeve 12 and the shaft 2, which accommodates differential
thermal expansion of the sleeve and the shaft. The gap may be
filled with an expansion gasket, for example a sheet of ceramic
paper.
[0074] The refractory component may of course have different
dimensions, according to the purpose for which it is intended.
Typically, however, the ranges for those dimensions will be
approximately as follows:
2 Preferred Dimension value Range A Angle of recess walls
60.degree. 20.degree.-89.degree. B Expansion gap 1 mm 0.5-5 mm C
Thickness of sleeve 7 mm 1-25 mm D Length of sleeve below metal
level 150 mm 50-300 mm E Length of sleeve above metal level 100 mm
50-300 mm F Diameter of shaft 40 mm 20-200 mm G Height above
surface of graphite 5 mm 0-24 mm
[0075] The invention is applicable to degassing, gas-injection,
flux-injection, chlorine-injection, stirring, moving and treatment
of liquid aluminium, its alloys and non-ferrous metals, where a
graphite part is immersed into the liquid metal. The invention is
also applicable to refractory components used in the production and
refining of ferrous metals, where a graphite part is immersed into
the liquid metal.
[0076] An example of such a component is shown in FIGS. 9-15, which
depict a component of a pump (a pump block 24) that, in use, is
partially immersed in the molten metal. The block 24 is made of
graphite and is substantially cuboidal in shape, with a shallow
groove 26 that extends along one face 28, parallel to the
longitudinal axis of the block. In use, the block is held upright,
with the longitudinal axis vertical, and with the bottom third of
the block 24 is made of graphite and is substantially cuboidal in
shape, with a shallow groove 26 that extends along one face 28,
parallel to the longitudinal axis of the block. In use, the block
is held upright, with the longitudinal axis vertical, and with the
bottom third of the block immersed in molten metal. The block is
therefore prone to erosion where it passes through the surface of
the metal.
[0077] To prevent erosion, the block 24 is provided with a ceramic
sleeve 30 that extends around the block to protect the area subject
to erosion. The sleeve extends a few centimeters above and below
the metal line, to allow for variations in the depth of the
metal.
[0078] The sleeve 30 is located in a recess 32 provided in the
block 24. The recess 32 comprises a shallow slot having a depth of
about 3 mm that extends around the circumference of the block. The
circumferential walls 34 that define the upper and lower edges of
the recess 32 are inclined towards one another, at an angle of
about 60.degree. to the external surface of the graphite block.
These walls serve to retain the sleeve in the recess. An expansion
gap 36 is provided behind the sleeve.
[0079] The ceramic materials used in the sleeve and the method of
manufacturing are substantially as described above.
[0080] The methods described herein may also be employed for
manufacturing protective sleeves for other graphite components used
in the aluminium industry, which are prone to erosion owing to
contact with the molten metal.
* * * * *