In-Line Degassing Unit (Dual-Rotor) for Aluminum Melt

Remove hydrogen and slag from your aluminum melt inline — before it becomes scrap. The FDUII-30 fixed-box dual-rotor degassing unit is installed directly in the melt transfer line between the melting/holding furnace and the casting table, treating 25–35 tons of aluminum per hour continuously. With two variable-speed graphite rotors (0–600 rpm) dispersing high-purity nitrogen or argon into fine bubbles, the unit guarantees ≥ 56% hydrogen removal: melt entering above 0.28 mL/100g leaves at no more than 0.14 mL/100g — the difference between sound billet and porous, cracked extrusion billet.

• ≥ 56% degassing efficiency with a written guarantee: outlet hydrogen ≤0.14 mL/100g (inlet >0.28) or ≤0.12 mL/100g (inlet <0.28).
• 25–35 t/h inline capacity — keeps pace with your casting line, no batch waiting.
• Dual-chamber, subsurface-flow design — melt never contacts outside air, cutting re-oxidation and surface slag.
• ± 2°C temperature control with 4×15 kW immersion SiC heaters and PID closed-loop regulation.
• Zero-downtime standby: working/idle gas pipelines auto-switch between casts so rotors never clog.
• Box lining life ≥12 months (high-strength integral castable), same class as our melting furnace linings.

Typical applications: billet casting lines (homogenizing-ready quality), slab/ingot casting, melt quality upgrades for extrusion and rolling plants, and foundries supplying automotive and aerospace-grade aluminum.

Degassing performance is where most suppliers go vague. Ours is written into the acceptance test: measured with a hydrogen density analyzer (e.g. Reduced Pressure Test or quantitative analyzer) at the inlet and outlet of the box, under 100% melt coverage.

*Efficiency ≥56% is the contractual guarantee under standard working conditions (N₂ purity ≥99.996%, rotor 0–600 rpm VFD, melt 680–770°C).

Why it matters: every 0.1 mL/100g of residual hydrogen in billet means blister, delamination and cracks during extrusion or heat treatment. Inline degassing at the transfer launders catches the hydrogen introduced by melting scrap and transfer — before it is locked into your casting.

• Gas control cabinet: flow meters, pressure regulators and gauges per channel (AirTAC pneumatic components), with three pipelines — working / idle / emergency. Between casts the system auto-switches to idle mode so rotors never clog; low-pressure alarm on the panel.
• Electrical control cabinet: touch-screen operation. Gas flow, pressure, rotor speed, heater and pool temperatures, and current values are all set and displayed on screen; over/under-temperature and power-regulator faults trigger flashing alarms (Delixi/Omron components).
• Heating system: 4 immersion heaters with thermocouple-monitored elements, PID closed-loop, soft-start thyristor control with undervoltage and overcurrent protection.
• Rotor drive: shaft concentricity deviation ≤ 0.5 mm for minimal surface disturbance; lubricated and cooled drive for continuous operation.

1. Melt enters subsurface — aluminum flows from the launder/holding furnace into the box below the melt surface, so the melt inside is never exposed to air. No new oxide film, no extra slag.
2. Fine bubbles disperse through two rotors — dry nitrogen or argon (≥99.996% purity) is injected through two counter-rotating composite graphite rotors at 0–600 rpm. The dual-chamber box (optimized by water-model simulation) breaks the gas into millions of micro-bubbles and distributes them evenly, leaving no dead corners.
3. H₂ diffuses into bubbles; slag is adsorbed — dissolved hydrogen diffuses into the rising bubbles and escapes through the exhaust port; fine oxide inclusions are adsorbed onto bubble surfaces and float to the dross layer. A protective inert gas blanket (0.5–1.0 m³/h) over the melt surface prevents re-oxidation.
4. Melt exits clean, at temperature — ±2°C PID-controlled immersion heaters hold the melt at casting temperature (680–770°C) during the entire transit; melt flows out to the casting table continuously at 25–35 t/h.
5. Between casts — idle protection — the gas cabinet switches to the idle pipeline (low flow) so rotors stay clear and ready; the emergency pipeline is on standby.