The eaf shells is a metallurgical smelting furnace.

The eaf shells is a metallurgical smelting furnace. The corrosion of molten steel and slag during the smelting process will cause loss of refractory materials in the lower furnace shell. Generally, the lower furnace shell needs to be replaced (lifted) once for 300 400 furnaces. For one-time replacement and its own daily maintenance and other tasks, the furnace cover and upper furnace shell must also be lifted. At present, the lifting and transportation of large-capacity electric arc furnace covers, upper furnace shells and lower furnace shells are carried out in different ways and with different spreaders. The hoisting of the furnace cover and the upper furnace shell is usually carried out by a single crane through a wire rope sling. 

There are four ways to lift the lower furnace shell 

(I) Two cranes are used to lift the pole beam + steel wire rope; 

(2) Two cranes are used to lift the pole beam + special spreader for the lower furnace shell + steel wire rope; 

(3) A single crane is used for hoisting by steel wire rope;

 (4) A single crane is used for hoisting by special spreader + steel wire rope for the lower furnace shell. 

Among them, the lifting methods of (I) and (3) have problems such as the steel wire rope squeezing and abrading the upper part of the lower furnace shell, and the steel wire rope is unbalanced in force, at the same time, the furnace body is unbalanced and difficult to position; 

(I) The lifting methods of

 (2) adjust the balance of the furnace body through the different lifting heights of the two cranes in the process of lifting the lower furnace shell. The synchronization is poor, and it will cause difficult production organization and labor labor. 

The problem of high strength and long operation cycle; although the lifting methods of (2) and (4) adopt the special spreader for the lower furnace shell, the spreader must be equipped with a special storage rack, which increases the investment. In summary, in the prior art, in order to complete the lifting work of the furnace cover, the upper furnace shell, and the lower furnace shell, three kinds of hoisting tools (cables) are needed as a spare. This not only increases the investment, occupies the limited working space of the workshop, but also increases the difficulty of management. In addition, the lower furnace shell must be equipped with a special spreader storage rack, which also increases the investment.

The problem to be solved In the prior art, the electric arc furnace cover, the upper furnace shell and the lower furnace shell are inconvenient to lift and transport, and the investment cost of lifting equipment is high. The present utility model provides an electric arc furnace cover and the upper furnace. The shell and the lower furnace shell use a double-hook three-in-one spreader, which can avoid the squeezing and abrasion of the upper part of the suspended object caused by the steel wire, reducing the labor intensity of the workers and shortening the working time, low cost, and simple operation. Technical Solution The purpose of the utility model is to adopt the following technical solution to realize the electric arc furnace cover, upper furnace shell and lower furnace shell of the utility model with double hook type three-in-one spreader, which includes a rectangular box frame. The upper surfaces of the front and rear two horizontal sides of the rectangular box frame are symmetrically provided with lifting rings off the center. The upper and lower parts of the left side of the rectangular box frame are respectively provided with protruding first horizontal sections. The upper and lower parts of the right side of the box frame are respectively provided with a second horizontal section and a third bending section connected in sequence. The upper surfaces of the front and back two horizontal sides of the rectangular box frame coincide according to the center of gravity of the suspended object and the three-in-one spreader. After comprehensive consideration, a hoist ring is set at an appropriate position off the center on the horizontal side.