SMFFA-50K-G 50 kg Gas-Fired Stationary Crucible Furnace

SMFFA-50K-G is a gas-fired, stationary (non-tilting) crucible furnace we designed for melting and holding aluminium and its alloys; metal is taken from the crucible by ladle. It is the gas-fired sibling of the electric SMFFA-50K-E. The body sits directly on the floor. The chamber is built around a Morgan Excel E BX176E bale-out crucible (≈58 kg Al). Combustion gas leaves the chamber at the top, descends inside the wall and goes to the recuperator and stack on a fixed station on the floor.

Gas path: out at the top, down inside the wall

The burner fires tangentially into the chamber at the level of the crucible base. The flame wraps the crucible pedestal, then the combustion gas spirals up around the crucible and sweeps it over its full height. The gas leaves the chamber at the very top, so no gas can short-circuit from the burner to the flue without heating the upper half of the crucible. The exit sits in the last wall segment before the burner in flow direction; the gas travels almost a full turn around the crucible before it gets there.

From there the gas enters a down-channel built inside the wall. The channel lies between chamber and shell and is separated from the chamber by a precast high-alumina (LCC 70% Al₂O₃) baffle; both faces of the baffle are hot, so it needs no insulation. Behind the channel is lightweight castable, 1260 °C board and microporous board, which keeps the steel of the channel pocket in the shell cool. The gas descends inside the channel and leaves under the body. From outside there is no flue duct leaning on the shell or cutting through the platform; the platform floor is continuous.

Elbow box and fixed station

As the furnace does not tilt, the channel is flanged to a single lined elbow box behind the furnace; a floor duct from the box carries the gas to the fixed station. The recuperator, lined stack, combustion air fan and air butterfly valve are on this station, on the floor. The gas line is rigid pipe and the hot air pipe is one piece; there are no flexible hoses. The station is the same as on the tilting TMFFA-G series, which keeps spare parts and service common.

Burner and combustion air

The standard burner is a BIO 50 class gas burner (Kromschröder), 40 kW. Combustion air is preheated by the flue gas in the recuperator on the fixed station. Gas/air ratio is held by a ratio regulator and air flow is set by a motorised butterfly valve; an air pressure switch and flame supervision are standard. The burner zone is protected by 1650 °C class LCC 70% Al₂O₃ castable.

Lid and metal take-out

The lid is lifted and swung aside with a counterweighted hand lever; hydraulic opening is optional. Metal is taken from the open crucible by ladle. The burner control units are in the main control panel. The crucible mouth is close to floor level, so the operator works from the floor; no platform is needed. As the body sits on the floor, a thermal separator plate under it is recommended.

Refractory and insulation

The floor is multi-layer: LCC 60% alumina castable, 1260 °C class board and microporous board. Thicknesses are chosen so that the microporous layer stays below its class limit; on the 08-G master model the floor steel is ≈133 °C by calculation. If the crucible cracks, molten metal is drained out through a channel in the floor refractory. The chamber has control and over-temperature (limit) thermocouples plus a spare thermocouple port.

Design checked by calculation

The position of the gas exit was compared with the thermal cycle model: on the 08-G, moving the exit from beside the burner to the top cut melting time from ≈84 to ≈74.5 minutes and consumption from ≈68.5 to ≈61 Nm³/t. The flame path and heat flux on the crucible were studied with flow analysis (CFD), which confirmed the burner direction.

Technical data

Technical values come from our design, thermal and flow (CFD) calculations; melting time and consumption are the cycle model of the 08-G master model adapted to each size. Final values are confirmed at project stage. Images are produced from the 3D design of the product.

We manufacture the furnace together with the chamber, burner and gas train, the fixed connection station (recuperator, fan, stack) and the control panel, and install and commission it on site. We work with you on other capacities, burner and crucible choice at quotation stage.

For price and lead time, use the Request a Quote button or call +90 533 945 27 94.

Tags: SMFFA-50K-G, 50 kg gas stationary furnace, gas-fired stationary furnace, gas crucible furnace, bale-out crucible furnace, aluminium melting furnace, recuperative crucible furnace