Single box single rotor degassing equipment
The single box and single rotor configuration is the most basic configuration in the sinking system. A rotating blowing rotor is arranged inside a single degassing box, and the melt flows in from the inlet end, passes through the rotor stirring blowing zone to complete gas-liquid contact mass transfer, and flows out directly into the casting process from the outlet end. The box body is generally constructed with refractory materials as a whole or prefabricated flow channels. The effective residence time of the melt inside the box is usually 30-60 seconds. The rotor speed is mostly controlled at 300-600 rpm, and the inert gas flow rate is dynamically adjusted according to the hourly flow rate of the melt and the hydrogen content of the incoming material.

The core advantages of this configuration are reflected in three aspects: firstly, it has a compact structure, small footprint, low equipment investment cost, and is very suitable for small and medium-sized casting production lines with limited space; Secondly, the control logic of the single rotor system is simple, the operation and maintenance threshold is low, and operators can get started after basic training; Thirdly, the melting process is short and the temperature drop during transportation is small, which can correspondingly reduce the energy consumption of melting and heating, while reducing the secondary oxidation and hydrogen absorption of the melt caused by long processes.

Its limitations are also evident: firstly, the melt only undergoes a first stage injection treatment, with limited residence time, and there is a ceiling to the degassing efficiency. The conventional hydrogen removal rate is in the range of 40% to 60%, which is difficult to meet the extremely low hydrogen content requirements of high-end products; Secondly, there are local dead corners in the single rotor stirring flow field, and some melts do not fully contact small bubbles, resulting in insufficient processing uniformity and significant fluctuations in hydrogen content; Finally, the equipment has a lower capacity limit and is only suitable for small and medium-sized production lines with an hourly flow rate of less than 10 tons. Single box single rotor equipment is widely used in product scenarios with relatively relaxed hydrogen content requirements, such as building profiles, ordinary industrial profiles, and low-end die-casting parts.

Dual box dual rotor degassing equipment
The dual box and dual rotor are arranged in series with two-stage degassing boxes, and each box is independently equipped with one rotating blowing rotor. The melt is sequentially purified through two-stage blowing to achieve gradient purification. The two-stage rotor can independently regulate the speed, gas flow rate, and working mode. Usually, the first stage is responsible for the coarse degassing function, removing most of the hydrogen content in the melt; The second level is responsible for refining Qi energy and stabilizing the hydrogen content at the terminal outlet. Partial optimization design will set up a static buffer zone and slag barrier between the two stages of the box to promote the full floating of bubbles and the separation of floating slag, further improving the purification effect.

Compared to single-stage equipment, the advantages of the two-stage configuration are very prominent: firstly, the two-stage series treatment extends the effective residence time of the melt to 60-120 seconds, and the hydrogen removal rate can reach 60% -80%. After treatment, the hydrogen content of the melt can be stably controlled at 0.12~0.15ml/100g Al, which can meet the quality requirements of most intermediate end plate strips, foils, and high-end industrial profiles; Secondly, the two-stage process parameters are independently adjustable, allowing for flexible matching of processes based on fluctuations in incoming hydrogen content, resulting in stronger adaptability to different alloys and furnace materials; Thirdly, the equipment investment and land occupation scale are moderate, achieving a good balance between purification performance and economy.

The main shortcomings of dual stage equipment are: significant increase in equipment length, larger footprint than single rotor systems, corresponding increase in melt temperature drop, and some low-temperature sensitive alloy production lines require matching heating devices for temperature compensation; Two sets of rotor systems operate synchronously, doubling the consumption of consumables such as graphite rotors and increasing maintenance costs accordingly; At the same time, the number of flow channel interfaces has increased, which increases the risk of slag hanging and slagging, and correspondingly increases the workload of furnace cleaning and maintenance. At present, dual box dual rotor is the mainstream selection for mid-range product lines with medium production capacity, widely used in the casting process of aluminum foil blanks, PS plate bases, automotive profiles, photovoltaic frames and other products.

Three box three rotor degassing equipment
The three box and three rotor system is the highest configuration of atmospheric pressure sinking degassing. The three-stage degassing boxes are arranged in series, and the three rotors are independently driven to form a three-stage deep purification system of "coarse degassing fine degassing final degassing". The high-end design sets up slag walls and static settling zones between each level of the box, separating floating slag and bubbles step by step, maximizing gas-liquid mass transfer and slag liquid separation effects. The total residence time of the melt in the system can reach 120-180 seconds, making it the process route with the highest purification depth under atmospheric pressure.

The advantages of tertiary equipment are concentrated in the purification performance aspect: firstly, the hydrogen removal rate of tertiary deep treatment can reach over 80%, and the hydrogen content at the outlet can be reduced to below 0.1ml/100g Al under stable operating conditions, with a purification effect close to that of entry-level vacuum degassing equipment; Secondly, the multi-stage processing technology has strong fault tolerance. Even if there are significant fluctuations in the hydrogen content of the incoming materials, the terminal hydrogen content can still remain stable, making it very suitable for continuous high-quality production; Finally, the equipment operates in a normal pressure environment without the need for complex sealing and vacuum systems, with higher reliability than vacuum degassing equipment and relatively lower maintenance difficulty.

The shortcomings of this configuration are also significant: firstly, the equipment occupies a large area, the investment cost is high, and it is only suitable for large-scale high-end production line configuration; The second reason is that the melting process is long and the temperature drop is large, usually requiring an electric or gas heating system to compensate for the temperature, further increasing energy consumption and operating costs; The third is that three rotors work simultaneously, which consumes a large amount of consumables and incurs higher daily operating costs than single-stage and two-stage equipment. The three box three rotor equipment mainly serves high-capacity production lines with extremely strict requirements for hydrogen content and inclusions, such as high-end tank materials, automotive body panels, aerospace aluminum alloys, high-precision electronic foils, etc.