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materials/solids processing
➠
Complete with motor gearbox, all mounted on a Impurities with debris or other objects are kept inside
baseplate that matched the previous seepex pump the filter until flushing. As an option the process can be
exactly, it was simply a case of dropping the Chroma controlled through differential pressure measurement.
pump into position, reconnecting the pipework and However, a timer is always used in order to prevent the
electrics and the pump was up and running, all with no basket getting too dirty.
additional installation costs. Since its installation, the Flushing is conducted in two steps. At the first
pump has performed trouble free for almost a year now step, a flushing valve is opened and debris collected
and is backed up by a standard five-year warranty. in the debris section, is released. At the second step
(backflushing), a flow diverter valve placed in the basket
Filter tackles clogging and fouling
closes while the flushing valve remains open. The closing
Thirty years ago Alfa Laval patented its first automatic, of the diverter valve causes the full stream to divert.
self-cleaning filter. Over the years this technology has After passing through the inlet section of the filter
been further developed and refined. Recently a large- basket, a part of the stream backflushes the rear
capacity model was added to the range - the ALF80-R section of the filter basket to dislodge stuck debris. This
(Fig. 2) ensures efficient cleaning of the basket, and debris is
When the supply of high-quality water for closed thus released through the flushing outlet. Meanwhile
loop cooling is limited or as in some parts of the world the majority of the stream passes through the filter
very expensive, a widely accepted solution is to use outlet being cleaned as usual.
water from the sea, lakes and rivers. However, solving
one challenge creates another. In this case, preventing
Slurry valve success
particles in low-quality cooling water from causing Meanwhile, Tyco Flow Control has designed and
excessive fouling and expensive down time. delivered a pneumatically operated cyclone distributor
The ALF can be used in many sectors of industry, consisting of 18 Clarkson KGD slurry valves to a
including power plants and district heating and cooling goldmine in Western Australia.
systems. It operates as an integral part of such a cooling To install the Clarkson valves the customer’s
system to remove debris that can foul and cyclone distributor was removed from the
clog plate heat exchangers, tubular mine and taken to the company’s Kalgoorlie
condensers, cooling tower spray workshop where the job was completed.
nozzles and similar equipment. The valves were customised
The filter provides protection to enable them to fit into a
for all downstream equipment, compact area, but the modular
helping ensure better design of Clarkson valves made
performance along with longer this a relatively fast and reliable
service life, increased uptime and process.
reduced maintenance costs. The trial valves underwent
The ALF80-R is the largest preventative maintenance during their
member of the filter portfolio
Fig. 2. A large capacity is capable of dealing
year and a half in operation.
family to date. This new model
with increasing demands for cooling water.
However the seats, once
is distinguished by a particularly removed, were found to have
large capacity, capable of dealing with the escalating significant life left in them.
demand for greater quantities of cooling water. Higher KGD Mark III sleeves are designed for slurry
capacity means fewer filters are needed, resulting in service and their new face and seal profile allows easy
reduced space requirements and less piping. installation and suitability for any pipe style without
The complete product range, with connections use of gaskets.
from 100-800 mm, features a flexible design that Whether closed or open the sleeve assembly
makes it easy to fit and install. Automatic backflushing provides positive sealing action protecting the metals
makes these filters easy to operate and helps ensure parts from the flowing slurry.
continuous operation, resulting in less down time. The application at the gold mine is a testing one
The low pressure drop through the filter permits with the cyclone located in the grinding circuit of the
a greater pressure drop for the downstream PHE or processing plant where it separates larger particles
condenser, which in turn makes it possible to use a of ore from smaller particles and returns them for
smaller heat transfer area and therefore fewer plates. grinding. Smaller particles move on to the next stage
This cuts down on the overall cost of the PHE and, says of the process where they are leached to extract their
the company, helps to provide customers with a more precious contents.
competitive solution. The valves’ suitability for the application was
In terms of how it works, water or other media is initially demonstrated by a trial installation of two KGD
first pumped into a filter basket. After having passed valves that functioned correctly for more than a year
through the filter basket, the media is discharged. and a half. v
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