The presence of Hydrogen is an important factor to be considered every time that an aluminum alloy is melted and a valid qualitative level has to be reached before casting. GAS DETECTOR is engineered to evaluate hydrogen presence in an aluminium alloy in order to intervene with a suitable degassing treatment before casting. The theoretical principle is the STRAUBE-PFEIFFER method. To carry out the test, a sample of aluminium alloy, brought to melt temperature in a melting furnace, is taken with a preheated cup. This sample is spilled into the appropriate preheated crucible, that is immediately placed, trough appropriate pliers, centrally on the base-plate and then covered with the bell. Vacuum condition, immediately created under the bell, will have to be maintained until complete solidification of metal sample. The sample is made solidify in vacuum because, in these conditions, the cavities and bubbles, due to gas contained in metal, assume significantly increased dimensions and therefore allow a first easier valuation of gas contents, according to principle that: a gas-free sample presents a concave surface, a very-gassy sample presents a convex surface.

With our experience and consolidated foundry practice in cleaning and degassing aluminium alloys, we have now available DUAL (degassing and cleansing unit for aluminium foundries), that makes possible a consistent, reproducible rotary degassing process throughout the melt and the automatic dosing of granulated fluxes for drossing-off, modification or grain-refining. The balanced rotation of the graphite impeller distributes a stream of micronized nitrogen or argon bubbles which eliminate porosities and transport impurities and oxides to melt surface. The unit consists of a rotating shaft + impeller and an insulated solid steel cover on which is mounted the pneumatic motor and the control cabinet. The cover is fitted and insulated with highly resistant fiber boards with a thickness of 100 mm, protecting the electric and mechanical components. When positioning the degassing unit on crucible furnaces or transport ladles, the cover adheres to the top rim in order to avoid temperature loss and metal splashes. The rotation group is fitted with the pneumatic motor working at constant speed of 400 rpm. The unit is also equipped for an anti-vortex skim paddle. Fittings are provided to operate nitrogen and compressed air supply (3/8 inches). Pressure switch is also provided to adjust the minimum nitrogen pressure and compressed air at 5 bar. The process is activated by the control cabinet capable to manage the entire cycle. DUAL is suitable for easy transport by fork-lift truck, crane or chain tackle. The basic unit is provided with a number of additional options which could satisfy customer demand and budget. For the unit operation provide: nitrogen supply at 5 bar, compressed air at 5-6 bar, electric supply 220 V AC, 50/60 Hz.