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Better energy values, fewer charging operations

The first furnace from new company ZPF GmbH has proven its worth at Metallwerk Friedrich Deutsch where the foundry also operates one of the first ZPF furnaces built in 1993.
Economical, environmentally friendly aluminium melting technology has always been the prime focus of ZPF therm Maschinenbau. Since November 2013, the tried-and-tested and continuously improved melting furnaces have been produced under the name ZPF GmbH. The first installation was delivered in February, not entirely by chance to a customer who is still operating six first-generation ZPF furnaces from 1993 - Metallwerk Friedrich Deutsch GmbH, market leaders for ski edges and a major supplier to the automotive industry. The plant is currently running at full capacity and has already proven to be exceptionally economical. 
The metal-working factory Friedrich Deutsch in Innsbruck is primarily known for its pre-shaped and partly pre-finished steel edges for the ski and sports industry. In addition, the company manufactures pressure diecast aluminium components for all the prominent car manufacturers in Europe - several thousand tonnes of material is melted at their mill every year. So far, this work has been undertaken by six melting and holding furnaces from ZPF therm in 24-hour continuous operations. “An expansion was, however, necessary for capacity reasons”, explains Hubert Tilg, manager of the diecasting division. “Because we were absolutely satisfied with the existing furnaces and they offer an excellent price-performance ratio as well, it was clear that we would again opt for ZPF.” A further factor was that, because of their familiarity with the ZPF melting facilities, the staff at the metal working factory can continue to carry out most of the maintenance work on the new furnace themselves.
In only three months, the required installations were manufactured in Siegelsbach in the state of Baden-Wuerttemberg and delivered to the customer. The system consists of an aluminium melting furnace with a melting capacity of 1,500kg/h and a holding bath for 5,000kg, an attached charging machine, and a 17” filtering furnace for cleaning the molten metal. “Thanks to its size, the new melting furnace yields much better energy values and is thus even more economical than the previous systems,” said Tilg. “Apart from that, the larger charging system doesn’t need to be loaded so frequently, a further factor which reduces energy consumption and increases performance.” 

Saves energy and reduces emissions thanks to special construction 
ZPF furnace engineering aims generally to keep the energy consumption as low as possible and implements flue gas reversal to achieve this. With this principle, instead of the hot flue gases from the melting process being discharged straight away, they are routed inside the furnace in such a way that their heat can be used to hold the molten aluminium at a high temperature. In addition, the combustion chamber made of refractory concrete acts not only as a separating layer between the aggressive liquefied aluminium and the outer shell of the furnace, but also as insulation, reducing the emission of heat to the surrounding area and functioning as an energy accumulator. It is consequently much easier to keep the temperature inside the furnace at a constant level. In combination with the waste gas recirculation, the fuel requirement is very low making the furnace particularly efficient and environmentally friendly. At the same time, the longer route of the waste gases inside the melting system brings about lower emission values since practically all pollutants are burnt in the post-combustion process at over 800°C. This means that ZPF installations can be used without flue gas filters. 
Besides this, ZPF technology also has an impact on the melting quality and on the maintenance costs; the waste gases remaining inside the furnace generate a slight overpressure which prevents any additional oxygen from entering. The adverse reaction of oxygen with aluminium - which would cause corundum to form in the melt and on the inside walls - can consequently be kept at a very low level. This technique achieves both a higher degree of purity in the liquefied aluminium as well as reducing damage to the refractory walls, thus avoiding expenditure for relining and repairing the plant. 

Contract is continuation of long-standing business relationship
The melting furnace has been working to full capacity without problems since being commissioned in February. “We already have one of the first - if not the first - furnace made by the former company ZPF therm, and that is still in operation today, and we will continue working very closely with ZPF”, explains Michael Deutsch, CEO of Metallwerk Friedrich Deutsch. “ZPF is a partner with true ‘handshake reliability’ with whom you can go through the ups and downs of life. As a result of the new ownership, our confidence has increased even further.” The company is already considering ordering a further furnace in the medium term as an additional safeguard for the event of breakdowns.,