Efficient aluminium swarf melting
At the last GIFA exhibition in 2003, ZPF-therm GmbH introduced a new generation of furnaces for melting chipped aluminium machining swarf or turnings. Since then, despite the instabilities of the metal casting industry in Europe, ZPF has installed more than 30 chip melters – mainly to aluminium wheel manufacturers. The furnaces use an innovative but simple twin impeller metal movement system to rapidly submerge and mix a weight-controlled feed of aluminium chips into the molten metal bath.
Customers have reaped major cost advantages from installing these furnaces that are designed specifically for melting aluminium machining chips. One customer claims a financial pay-back of less than 6 months. The energy efficiency and melting loss is of particular interest. User tests have shown that when melting dry, clean chips, preheated to 200°C during the cleaning process, the energy used to melt and heat to 720°C, is only 650 kWh per tonne. The metal loss in this case is less than 1.5%. Even without preheating of the charge material, the energy needed is remarkably low at 750 kWh per tonne, and the melting loss is below 3%.
The process is very clean; any fume generated from oily residues on the feed material is extracted from the filling well and ducted to the furnace exhaust where it is burned prior to entering the chimney. A large hydraulically operated door gives full access for drossing off the melt and cleaning the furnace walls. The furnace is tilted hydraulically for discharging the molten metal.
The smallest standard unit has a melting rate of 500 kilograms per hour with a bath capacity of five tonnes. The largest furnace melts 1500 kilograms an hour and holds 15 tonnes of aluminium.
ZPF also makes a range of furnaces for bulk aluminium melting and holding, with ratings up to five tonnes per hour and holding capacities up to 20 tonnes. Other standard equipment in the range includes, automatic dosing furnaces, low-pressure diecasting furnaces, filter furnaces and ingot pre-heaters.
The latest ZPF installation in the UK is a compact shaft-type melting furnace rated at 500 kilograms per hour for supplying aluminium for low-pressure diecasting.
Ramsell‑Naber Ltd represents ZPF in the UK and Ireland. For further information see www.zpf-therm.de or via email to info@ramsell-naber.co.uk.