JPS5952358B2 - Scrap preheating device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a preheating device for preheating raw material scrap in electric furnace equipment for steelmaking.

FIG. 1 shows a typical process of a conventional steelmaking electric furnace equipped with a preheating furnace.

The exhaust gas from the electric furnace 1 burns combustible components such as carbon monoxide with air leaking from the joint between the electric furnace 1 and the preheating furnace 2, and then flows through the preheating furnace 2 filled with scraps from top to bottom. passing through, the scrap is preheated, its temperature is lowered, then it is cooled in a cooling tower 3, and dust is removed in a dust remover 4,
It is sucked in by the exhaust fan 5 and discharged into the air from the stack 6.

On the other hand, the scrap preheated in the preheating furnace 2 is charged into the electric furnace 1.

At first glance, the above equipment seems simple and highly efficient, but if you look closely, you will notice that the operation of the electric furnace 1 is carried out in batches, and the charging of scrap into the electric furnace is also carried out in two stages: initial loading, first additional loading, It is normal for this to be carried out multiple times, such as the second follow-up...
The power must be shut off each time, and therefore the preheating furnace must be operated in batches, and the operating conditions change significantly over time.

Now, in order to increase the operating efficiency of the electric furnace, it is necessary to shorten the charging time for scrap, so when the electric furnace is turned off and its lid is removed, scrap can be charged immediately. desirable.

Therefore, the preheating furnace must stop its operation before the power is cut off and wait out of the flow of the electric furnace exhaust gas. As a result, the high temperature electric furnace exhaust gas is transferred to the first stage without heat recovery. The waste passes through the bypass 2a shown in the figure and is wasted.

This dead period includes the time for transportably removing the preheating furnace from the electric furnace exhaust gas conduit, the time for inserting it into the conduit, the time for loading scrap into the preheating furnace, the time required for transporting the preheating furnace, etc.

In order to separate the preheating furnace from the electric furnace exhaust gas conduit, conventional methods have been used, such as lifting and moving the lid of the preheating furnace using an overhead crane, or switching between multiple preheating furnaces using a rotating lifting hood.

However, when attaching and detaching the lid using an overhead crane,
The time required for one operation was long and the operation was inaccurate.

In addition, in the case of the swivel lift method, since multiple preheating furnaces are operated, the preheating furnaces cannot operate during the switching operation, and the swivel operation has to be slowed down to eliminate inertial effects, which reduces the switching time. In addition, it took a long time, and due to the nature of the device, it required an excessively large structure in terms of height and strength.

An object of the present invention is to provide a preheating device (generally refers to the preheating furnace and its lid removal conveyance device) in which the dead time of the preheating furnace (period of non-use as a heat exchanger) is reduced.

The present invention will be specifically described below based on embodiments shown in the drawings.

Figure 2 shows an example of the preheating furnace 2, which is a steel plate.

Or a cast steel body 8, a bottom door 9, a lid body 10, and a hanging frame 1 pivoted on a trunnion protruding from the upper part of the body 8.
1, the main winding hook (not shown) of the overhead crane is passed through the hanging metal fitting 12 fixed to the upper end of the hanging frame 11, and the lid body 10 is removed and suspended in the scrap loading position and preheated. It can be transported to a position (that is, a position where it is inserted into an electric furnace exhaust gas conduit), a discharge position (that is, a position where it is charged into an electric furnace), and the like.

Is the electric furnace exhaust gas coming from the upper conduit 10a of the lid 10?

The scrap is introduced into the preheating furnace 2 in the direction of the arrow to preheat the scrap, and then enters the lower conduit 14 through a number of holes 13 provided in the lower part of the bottom door 9.

The body 8 and the lid 10, and the lower conduit 14 and the body 10 are removably connected by flanges 16a and 16b, respectively (see also FIG. 4).The preheating furnace with the lid 10 removed is Using an overhead crane, it can be inserted into and removed from the electric furnace exhaust gas pipe in a single hour.

In order to open the bottom door 9, when the chain 17 is pulled up with an auxiliary hoisting hook (not shown) of the overhead crane, the tie bar 18
Due to this action, the left and right bottom doors open in the same phase, and when the auxiliary winding hook is lowered, they close under their own weight.

Needless to say, the scraps are charged from above with the bottom door 9 closed and the lid 10 removed, so there is no need to close the bottom door while the bottom door is filled with scraps.

In addition to the above, the bottom door 9 may be a known type such as an orange peel type or a shutter type, with holes formed therein for passage of the electric furnace exhaust gas.

In addition to the cylindrical preheating furnace mentioned above, spherical preheating furnaces and ones in which scrap is charged and discharged by rotating the furnace through a single opening have also been proposed, but they do not allow exhaust gas to pass through. If so, don't worry about these things.

Furthermore, even if the electric furnace exhaust gas passes in the opposite direction to the arrow, the heat transfer effect remains almost the same, so there is no need to worry about the direction in which the exhaust gas passes.

Now, FIG. 3 and FIG. 4 show how the lid 10 is attached to and removed from the body 8, which constitutes the essential part of the present invention.
A lid body unloading and transporting device 19 for transporting 0 to another position is shown.

The upper tubular portion 10a and the lower conical portion 10b of the lid 10 are telescopically engaged via a laryngeable joint 20.

Further, the lower conical portion 10b is fixed to two piston rods 21, and the lid body as a whole can be moved up and down by a fluid cylinder 23 fixed to a support such as a truck 22, and is airtightly attached to the body 8 by a flange 16C. It can be brought into contact with and released from.

The truck 22 and the pair of lids form a lid pair.

On the other hand, the trolley 22 is supported by the rail 24, and the stopper 22
It is possible to travel within the area restricted by 5.

Instead of the fluid cylinder 23, a motor cylinder,
Of course, screw jacks, racks, pinion jacks, etc. can be used.

In order to transport and attach the lid 10 from another position to the body 8 of the preheating furnace, which has been filled with scrap and has been transported to the preheating position and placed there, a cart is used which carries the lid 10 at a high position by the fluid cylinder 23. 22 is conveyed by rails onto the body 8 by human or mechanical power, and the lid body 10 is lowered by the fluid cylinder 23, so that the flange 16C and the flange 16a are brought into contact with each other.

Further, in order to remove the lid 10 from the body 8, it is sufficient to lift the lid 10 with the fluid cylinder 23, and then the cart 22 is run on the rails 24 to transport it to another position.

The wheels 26 of the trolley 22 are supported by the rails 24,
This does not necessarily mean that the truck 22 is located higher than the rails 24; if necessary, the truck can be installed lower than the rails.

In addition, to connect the upper tubular portion 10a of the lid 10 and the electric furnace exhaust gas conduit, an expansion and contraction mechanism using a fluid cylinder 29 is installed on the electric furnace exhaust gas conduit side to shorten loading and unloading time and to ensure confidentiality. Although retention is intended, it goes without saying that an expansion/contraction mechanism using bellows or the like may be used.

The lifting height of the fluid cylinder 23 is sufficient to be 50 mm or less, and the loading and unloading of the lid 10 is normally performed within 3 minutes including the transportation time.

From the above description of the embodiment, the configuration and effects of the present invention in the case of one electric furnace and one preheating furnace are clear, but based on FIG. Preheating furnace 2A, 2B, two lid body removal conveyance devices 19A, 19B
We will explain the case using .

In the figure, preheating furnace 2A is in use and valves 28A, 28B
is open.

The preheating furnace 2B is stopped and during this period, the lid is removed,
Loading of scrap into the electric furnace, receiving of scrap into the preheating furnace, attachment of the lid, and transportation for these operations are completed.

(The figure shows the front of the lid device.) Once the lid is installed, the preheating furnace can be used effectively without wasting time by closing the valves 28A and 28B and opening the valves 28A and 28B.

Although one preheating furnace may be used, it goes without saying that if the period in which two preheating furnaces are used together is increased, the amount of heat recovery will further increase and the load on the exhaust fan will be reduced.

If the number of preheating furnaces and lid body removal conveyance devices is further increased, the parallel operation time will further increase, the amount of heat recovery will increase, and the load on the exhaust fan will be reduced.

Since the present invention has the above-described configuration, it is simple, accurate, and
The preheating furnace can be installed and removed in a short time and at low cost, thus increasing the effective usage time of the preheating furnace and increasing the amount of heat recovery.

Furthermore, if you use two preheating furnaces together, there will be no wasted time.
Furthermore, by operating two preheating furnaces in parallel, the amount of heat recovery can be increased and the load on the exhaust fan can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a process diagram showing an example of electric furnace equipment for steelmaking, FIG. 2 is a partially cutaway front view showing an example of a preheating furnace, and FIG. 3 is a front cross-sectional view showing a lid removal conveyance mechanism. FIG. 4 is a plan view illustrating a case where two preheating furnaces and two lid mounting/removing devices are used for one electric furnace. 7... Preheating furnace, 8... Preheating furnace body, 9
...Bottom door, 10... Lid body, 11...
... Hanging frame, 19 ... Lid body unloading transfer device, 20 ... Flexible joint, 22.
...Dolly, 23...Fluid cylinder, 2
4...Rail, 27...Saddle.

Claims (1)

[Scope of Claims] 1. A device capable of being housed and removed from the middle of an electric furnace exhaust gas conduit while being insulated by a sealing means,
In the scrap preheating device, there is a pair of preheating furnaces that are inserted in parallel and can be used alternately, the preheating furnaces can take in and out the scrap, and the electric furnace exhaust gas can pass through the built-in scrap. ; The pair of preheating furnaces are separable into a body and a lid; they are installed so that they can be attached, detached, and transported with a horizontal gap that allows at least one lid; the pair of lids are mounted on a rail. is mounted on a movable support so that when the lid body (2) is engaged with the body (1), the other lid body is movable up and down so that the other lid body is located between the installation positions of the pair of preheating furnaces. are fixed to form a pair of lids; move the pair of lids along the rail, and insert one pair of preheating furnaces alternately in the middle of the electric furnace exhaust gas pipe, with the other insulated from the pipe. A scrap preheating device characterized in that: and the lid can be left in a removed state;