The Electric Arc Furnace (EAF) Shell: A Metallurgical Smelting Furnace Overview

The Electric Arc Furnace (EAF) shell is a crucial component in metallurgical smelting operations. During the smelting process, the corrosive action of molten steel and slag leads to the gradual loss of refractory materials in the lower furnace shell. Typically, the lower furnace shell requires replacement (lifting) after every 300 to 400 furnaces. For comprehensive maintenance tasks, including one-time replacements and daily upkeep, both the furnace cover and the upper furnace shell must also be lifted. Presently, the lifting and transportation of large-capacity electric arc furnace covers, upper furnace shells, and lower furnace shells are accomplished using various methods and spreaders. The furnace cover and upper furnace shell are usually hoisted by a single crane using a wire rope sling.

Four Methods for Lifting the Lower Furnace Shell

1. Dual Crane Lifting with Pole Beam and Steel Wire Rope: This method involves using two cranes to lift the lower furnace shell with the aid of a pole beam and steel wire ropes.
2. Dual Crane Lifting with Pole Beam, Special Lower Furnace Shell Spreader, and Steel Wire Rope: Here, two cranes are employed, utilizing a pole beam, a specialized spreader designed for the lower furnace shell, and steel wire ropes.
3. Single Crane Hoisting with Steel Wire Rope: This approach relies on a single crane to hoist the lower furnace shell using only steel wire ropes.
4. Single Crane Hoisting with Special Spreader and Steel Wire Rope for Lower Furnace Shell: In this method, a single crane is used, equipped with a specialized spreader and steel wire ropes tailored for the lower furnace shell.

Issues with Existing Lifting Methods

• Methods (1) and (3): These approaches suffer from problems such as the steel wire ropes squeezing and abrading the upper part of the lower furnace shell, leading to imbalanced force distribution. Consequently, the furnace body becomes unbalanced and difficult to position accurately.
• Method (2): Although this method attempts to adjust the balance of the furnace body by varying the lifting heights of the two cranes, it often results in poor synchronization. This, in turn, complicates production organization and increases labor intensity and operational cycle times.
• Methods (2) and (4): While these methods utilize a specialized spreader for the lower furnace shell, they necessitate the installation of a dedicated storage rack for the spreader, thereby increasing investment costs.

In summary, the prior art requires three different types of hoisting tools (cables) as backups to complete the lifting tasks for the furnace cover, upper furnace shell, and lower furnace shell. This not only escalates investment costs but also occupies valuable workshop space and complicates management. Additionally, the need for a specialized spreader storage rack for the lower furnace shell further increases expenses.

The Problem and Technical Solution

The challenge in the prior art lies in the inconvenience and high investment costs associated with lifting and transporting the electric arc furnace cover, upper furnace shell, and lower furnace shell. To address this, the present utility model introduces a double-hook three-in-one spreader designed specifically for these components. This innovative spreader eliminates the squeezing and abrasion caused by steel wire ropes on the upper part of the suspended object, thereby reducing worker labor intensity, shortening working times, and offering a cost-effective and straightforward operation.

Technical Implementation

The utility model achieves its objectives through the following technical solution: The double-hook three-in-one spreader for the electric arc furnace cover, upper furnace shell, and lower furnace shell comprises a rectangular box frame. The upper surfaces of the front and rear horizontal sides of this frame are symmetrically equipped with lifting rings positioned off-center. The left side of the rectangular box frame features protruding first horizontal sections at both its upper and lower parts. On the right side, the frame is furnished with a second horizontal section followed by a third bending section, connected sequentially.

The placement of hoist rings on the horizontal sides of the rectangular box frame is determined based on a comprehensive consideration of the suspended object's center of gravity and the spreader's design. Consequently, hoist rings are strategically positioned off-center on the horizontal sides to ensure optimal balance and stability during lifting operations. This thoughtful design ensures efficient and safe handling of the electric arc furnace components, addressing the limitations of prior art methods.

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