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Alucote is a novel fibre
gunning system developed by Clinotherm, the refractory services division
of Dyson Hotwork Ltd, to encapsulate Refractory Ceramic Fibre (RCF)
linings with a monolithic layer of alumina fibre. The system virtually
eliminates the formation of hazardous RCF dust by complete encapsulation
of the lining, thus providing a fast and effective way to deal with
the recent reclassification in Europe of RCFs as category 2 carcinogens.
By improving the thermal efficiency of a refractory lining, be it
fibre or dense refractory, Alucote also minimises the effect of carbon
taxationmay have on a company's profitability.
- Alucote uses an Alumina Fibre which is not classified.
The fibre used in this gunning process is a polycrystalline alumin fibre
which is not classified under European directive 97/69/EC. This alumina
fibre was originally designed to minimise biological effects and toxicology
result to confirm that these design principles are effective.
- Improved Thermal Efficiency.
In terms of insulating property, this fibre is 38% more efficient than
standard ceramic fibre and a layer of alumina fibre sprayed onto an
existing fibre lining would not only solve the problem of RCF dust release
but also improve the insulation of the existing lining. Based on Alucote
thicknes of 25-50 mm, energysavings of 13-24% can be achieved.
- Higher productivity and production flexibility.
Due to the high temperature classification of this alumina fibre of
1600°C, an added advantage of applying Alucote to an existing lining
is that it enables furnace and kiln operators to run their processes,
if necessary, at higher temperatures than before without any detriment
to the lining. This could lead to higher productivity in the case of
a continuous plant where product residence times can sometimes be reduced
at higher processing temperatures. Alucote can also improve production
flexibility as products requiring higher processing temperatures can
now be run through the upgraded plant, which would otherwise not have
been possible due to original design constraints.
- Rapid application speeds up lining repairs and minimises downtime.
With an average application rate of 25 square metres per hour, Alucote
provides an extremely fast method of repairing a refractory lining,
which represents a clear benefit in case of emergency breakdowns. In
the context of a planned shutdown, Alucote can be applied to a refractory
lining in just one day, where traditional methods could take several
days. When the cost of a day's downtime is considerable, the time saved
alone justifies the use of the Alucote method. |
- Longer lasting lining for a wide range of applications.
The type of alumina fibre used is renowned for its low shrinkage which,
along with its higher
temperature rating, contributes to prolonging lining life.The substrates
onto which Alucote can be applied range from Refractory Ceramic Fibre
installations to brickwork and dense castable constructions
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- Designed to encapsulate RCF and dense refractory
linings.
- Uses non-classified alumina fibre.
- Up to 25% heat loss reduction.
- Rapid lining repairs.
- Operating temperaure up to 1600°C
TYPICAL APPLICATIONS
- Reheat and heat-treatment furnaces.
- Intermittent kilns.
- Installations with exposed RCFs.
Installations with excessive heat losses.
- A fibre coating system which conforms with stringent safety
legislation.
There are a number of risks which have to be assessed under certain
Health and Safety Statutes such as, in the UK, COSHH Regulations, Confined
Spaces Regulations, Health & Safety at Work Act (1974) and any other
applicable regulations. Therefore, prior to any application of Alucote,
a full risk assessment of the site must be carried out.
The development of Alucote is based on safety both during and after
its application once the coating is in service. This is achieved by
choosing a fibre which has been developed to minimise biological activity,
by preventing dust release during the application and also by selecting
the appropriate ingredients for the binders.
The very low content of silica and the structure of the alumina fibre
ensure that Alucote does not devitrify and form crystalline silica
at high temperatures, which is an issue with RCFs exposed to high
temperatures for a prolonged period of time.
When the surface to be coated is composed of Refractory Ceramic Fibres,
exposure to RCF dust of operators inside the furnace or kiln and other
personnel on site must be controlled and minimised. By following set
procedures, entry and exit points are sealed off, a high efficiency
dust extractor is installed to prevent RCF dust from escaping into
the atmosphere and operators are equipped with appropriate respirators.
All P.P.E. is checked before and after the installation.
The integrity of the exlsting lining must also be assessed before
applying a layer of Alucote. It may be necessary to apply a prior
coating that would reinforce the substrate. If the substrate allows
Alucote to be applied directly, it is then pre-wetted with the binder
solution to minimise airborne dust. In order to prevent the creation
of dust in a dry state from the application of Alucote, the gunning
equipment makes use of a specially designed nozzle which ensures that
all fibres ejected from the nozzle are coated with the binder solution.
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