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Industrial vacuum furnaces for heat treatment |
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| 2008.07.22 B5_R : fast and economical tempering We have already introduced, in previous editions of our Newsletter, our range of B5_RN furnaces for ALLNIT®-type low-pressure nitriding. The B5_RN is directly descended from the B5_R, keeping the latter’s characteristics and advantages. The B5_R furnace is principally designed for low-temperature heat treatments such as tempering, stress releaving, ageing etc. The B5_R is the culmination of over 30 years of development and changes. Starting out as the B6_R in 1975, to then become B7_R then B5_R in the 90s, BMI tempering furnaces have widely demonstrated their qualities and have naturally found a place in heat treatment workshops due to their reliability, performance level and longevity! We should note that many first generation B6_Rs are still in use after 30 or so years of production based on the B64R n°12231 and B63R n°12226 of 1978. Benefiting from the experience of the B6_R et B7_R series, the B5_R represents the ultimate in advanced technology and simplicity: - single turbine for heating and cooling, - a high-performance fibrous insulation muff, combining low inertia and exceptional insulation power, - an optimal heating chamber design, as much in terms of resistance as in terms of convector circuit, providing remarkable thermal homogeneity, reaching +/- 3°C when loaded, depending on conditions, - possibility to carry out a sub zero treatment before tempering without altering the surface state (*CoolPlus* system). In the investment phase, our clients and prospective clients generally compare furnaces from the B5_R family to retort furnaces, which are often more attractive in terms of investment amount. To take comparison further, we have devised a comparison test game, usually the preserve of the car magazines, and the results are indisputable. With an equal load (420 kg), in furnaces of equivalent useful dimensions (600x600x900 mm), for an identical treatment (tempering cycle at 510°C with a tray time of 30 min on parts), the results are as follows. The result is that the B54R is nearly twice as fast and consumes 2.5 times less energy than the retort furnace. We note that the latter is penalised, when it comes to both consumption and cycle length, by the need to heat and cool down the retort. If we consider the “productivity” aspect, for furnaces operating 20 hours a day for 200 days a year, the retort furnace will complete 614 cycles per year, whereas the B54R will complete nearly 1200 cycles per year. Based on 0,1 €/KW, the 614 cycles of the retort furnace will cost nearly 17 806 € whereas the 1200 cycles of the B54R will only cost 13 800 €... This is an annual energy saving of nearly 7 000 € for twice the productivity. If it is generally noted that the B54R is 15 to 20% more expensive than a retort furnace of equivalent dimensions, this difference at the point of purchase will be easily compensated for within the 2 to 3 years following the investment. (On the basis of 600 cycles per year, the B54R will save nearly 10 500 € per year [based on 0,1 €/kWh]) This tendency should become even more pronounced with the global rise in energy costs foreseen for the years to come. The B5_R series’ competitiveness will once again affirm itself, making these furnaces the ultimate and perennial tool for all low-temperature treatments.  |
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| ©B.M.I. 2009 |