In a blazing torrent of fire, ash and intense heat, a specially constructed Kalmar truck, fitted with an almost five metre long pole, methodically goes about its work at the smelting furnace. At Elkems Silicon Division in Bremanger, 6-700 tonnes of 90-percent pure silicon is manufactured every week, prior to subsequent applications within the cutting-edge electronics industry, primarily in the USA and Japan.
When pole-raking in the furnace, the truck is exposed to extreme strains and stresses, as reported by Frank Fossedal, purchasing manager at Elkems Bremanger plant. The Kalmar truck has all the right credentials for coping with this highly exposed task.
At Elkems Silicon Division in Bremanger, siliceous ore is enriched into virtually pure silicon containing more than 90% metal. The process is intensive and takes place around the clock, every day of the year. At Elkems Chemical Works in Svelgen, silicon can be further enriched to attain a metal content of up to 99.9999% !
Production totals 6-700 tonnes a week, and the silicon is exported to two major customers, one in the USA and one in Japan. There it is purified further in order to achieve a metal content of slightly more than 99.99%; it is subsequently used within the computer and electronics industry, including the manufacturing of various data chips.
There arent many machines that can handle the extreme environment in which this so-called pole truck operates. Fitted with an almost five metre long solid steel pole, the machine repeatedly drives the pole into the white-hot furnace. A torrent of blazing ash and smoke is catapulted out at the machine. The heat radiation is intensive.
Over the years we have tried out a number of machines, but only Kalmars trucks have proved to be sufficiently robust in design and construction to cope with this exposed task, explains Frank Fossedal.
The high temperatures and the large quantities of dust and ash hurled out of the furnace not only generate immense stresses and strains on the machine exterior, there is also an obvious risk of fire and of all the dust penetrating and ruining essential components. In order to withstand such extreme conditions, this Kalmar truck has to be very special.
Sturdy, with a minimum of equipment
The machine has a heat-attenuating shield at the front and the wheels are covered so as not to melt. All standard equipment not absolutely necessary for the trucks operating tasks has been stripped away. This applies, for example, to much of the normal electrical gear. These radical modifications have allowed the risk of accidents to be minimized. Much work has also gone into creating as safe an environment as possible for the driver.
Kalmar has the best structural design, including adequate material thickness, and the truck is capable of working under these exposed conditions for long periods of time, notes Frank Fossedal.
The pole truck fulfils a special function but does not involve a particularly large number of hours operation a year. Conversely, the task needs to be performed every single day of the year. Recouping the cost of the machine also requires being able to exploit it for at least 7-8 years and, as mentioned, the availability requirement is crucial to the process at the Silicon Division.
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