RU2619652C2 - Roasting machine grate - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: roasting machine grate comprises upper and lower support horns, remote straps, working body formed by an upper working surface, a bottom surface and side surfaces, wherein grooves are made at least on one side surface from the upper working surface to the bottom surface along the direction of motion of heating carrier gas, their smallest width is equal to or less than the particle size of roasted metallurgical raw materials.

EFFECT: acceleratedb pellets annealing by increasing heat-carrying gas flow.

6 cl, 9 dwg

Description

The invention relates to the field of mining and metallurgical industry and can be used for roasting metallurgical raw materials on the grill of a roasting machine.

The productivity of the roasting machine largely depends on the magnitude of the flow of heat-carrying gas through the layer of calcined metallurgical raw materials, which, in turn, is determined by the resistance to the passage of gas through the layer of calcined raw materials and through the grate. The resistance of the grate is determined by the gap between the grates. The larger the gap, the lower the resistance for gases.

The size of the gap cannot exceed the value at which particles of metallurgical raw materials can wake up through the gap down under the grate. The specified limitation of the gap limits the magnitude of the flow of heat-carrying gas, and therefore the performance of the roasting machine.

The grate is described in A.S. USSR No. 1668836, the design of which provides the maximum possible inter-spike gap due to contact between the spacer bars of adjacent (neighboring) grates. However, a further increase in the gap is impossible due to the ingress of particles of metallurgical raw materials, such as pellets.

Another grate is known by A.S. USSR No. 851064 adopted as a prototype. In this grate, the resistance to the passing heat-carrying gas is reduced by performing the body of the grate of a triangular shape, and the distance bars (tides) are also made of a triangular shape, with vertices to the working surface.

However, this design does not provide a sufficiently intense flow through the roasting machine, since the size of the gap is determined by the size of the roasted particles of metallurgical raw materials, for example, the diameter of the pellets.

The task aimed at the proposed technical solution is to increase the productivity of the roasting machine by increasing the flow of heat-carrying gas between the grates by increasing the clearance between them.

The problem is solved in that in the grate of the roasting machine, including the upper and lower supporting horns, spacer bars, a working fluid formed by the upper working surface, lower surface, and side surfaces, in accordance with the invention on the side surface along the direction of movement of the heat-carrying gas grooves are made, the width of which is equal to or less than the particle size of the calcined metallurgical raw materials, for example, the diameter of the pellets. In this case, depending on the design of the grate, the length of the grooves may be equal to the width of the side surface in that place of the side surface where the grooves pass, and may be less than the width of the side surface in the place where the grooves pass.

The amount of clearance between the grates can be adjusted by the gap between the grates, which is determined by the full height of the distance bars, as well as the width and depth of the grooves. Moreover, the maximum values of the gap between the grates and the width of the grooves are interconnected and limited by the particle size of the calcined metallurgical raw materials, for example, the diameter of the pellets, which should not wake up in the gap between the grates. The presence of grooves reduces the cross section of the body of the grate and thereby reduces its strength. Therefore, the maximum depth of the grooves is limited by the load on the weight of the calcined metallurgical raw materials. The shape of the cross-section of the grooves (rectangular, round, etc.) with an equal cross-sectional area has little effect on the magnitude of the flow of heat-carrying gas and is selected based on the minimum complexity of manufacturing.

Depending on the required amount of heat-carrying gas flow through the gaps between the grates, the grooves can be made on both side surfaces of the grate, and can be performed on only one side of the grate.

If you need a slight increase in the flow of heat-carrying gas, the grooves on the side surface of the grate are located so that after installation of the roasting machine on the trolley, they are opposite the grooves of the neighboring grate, while the total height of the spacer bars is determined by the following formula:

where G ₁ is the total height of the spacer bars of the grate;

D is the particle size of the calcined metallurgical raw materials, for example, the diameter of the pellets;

B is the smallest groove width;

r is the radius of curvature of the angles formed by the side surface of the grate and joined with it by the surfaces of the grooves.

If it is necessary to maximize the flow of heat-carrying gas through the gaps between the grates, the grooves on the side surface of the grate are made so that after installation on the firing machine, they are located opposite the gaps between the grooves of the adjacent grate, while the total height of the distance bars is determined by the formula

where G ₂ is the total height of the spacer bars of the grate;

D is the particle size of the calcined metallurgical raw materials, for example, pellets;

B is the smallest groove width;

r is the radius of curvature of the angles formed by the side surface of the grate and joined with it by the surfaces of the grooves.

In the same way, the total height of the spacer bars for the grates with grooves on only one working surface is calculated if, when installed on the firing machine, the side with grooves of one grate is mated with the side without grooves of the adjacent grate.

If it is necessary to increase the flow of heat-carrying gas through the gaps between the grates to intermediate values between the maximum and minimum values, the grooves on the side surface of the grate are located respectively between the positions of the grooves, providing a slight increase in heat flux and a maximum increase in heat flux.

To prevent clogging of the grooves with small particles of metallurgical raw materials, they expand in the direction from the working surface to the lower surface (from top to bottom in the working position). The proposed solution considers the smallest groove width.

In the event that small particles of metallurgical raw materials are absent or are present in small quantities, then the grooves have the same width along their entire length - from top to bottom, from the working surface to the lower surface.

The invention is illustrated by drawings, in which

FIG. 1 depicts a grate, made in accordance with the invention, a front view;

FIG. 2 depicts a grate, made in accordance with the invention, a top view;

FIG. 3 shows a grid-iron made in accordance with the invention in section AA in FIG. one;

FIG. 4 depicts a grate, made in accordance with the invention, in a section bB in figure 1;

FIG. 5 shows a grate, made in accordance with the invention, with grooves made to the entire height of the side surface;

FIG. 6 shows a grate made in accordance with the invention with grooves made on one side surface;

FIG. 7 shows the relative position of the grooves of adjacent grates in the case of the grooves of one grate opposite the grooves of the neighboring grate;

FIG. 8 shows the relative position of the grooves of adjacent grates in the case of the grooves of one grate opposite the gaps between the grooves of the neighboring grate;

FIG. 9 shows the relative position of the grooves of adjacent grates in the case of an intermediate arrangement of the grooves with respect to each other.

As shown in FIG. 1 and FIG. 2, the grate includes the upper supporting horns 1; lower supporting horns 2; distance strips 3 with full height (G), that is, with a height equal to the distance between the side surfaces of adjacent grates; distance bars 4 with incomplete height, as they are located opposite the same distance bars on the adjacent grate. The sum of the heights of these distance strips 3, 4 is equal to the distance between adjacent side surfaces of the grates. The working body 5 of the grate includes the upper working surface 6 and the lower surface 7, as well as the side surfaces 8 of the body of the grate and the grooves 9. Two cross sections of the grate (A-A and B-B) are shown in FIG. 3 and FIG. four.

In this embodiment, the grate the width of the upper working surface is significantly greater than the width of the lower surface (high taper of the grate body in a vertical plane). For this reason, the length of the grooves (L) is less than the width of the side surface (E) (Fig. 3, 4).

In order for particles of metallurgical raw materials with sizes smaller than standard values, for example, pellets with a diameter smaller than that established by the technological process, freely wake up along the grooves 9 down and not clog them, the grooves 9 are made expanding downward (M is larger than B) (Fig. 1, Fig. 5 )

In that case, if the taper of the working fluid in the vertical plane is small, then the grooves 9 are made to the entire height of the side surface 8 (Fig. 5). If necessary, increase the flow of heat-carrying gas by a small amount of grooves are performed on only one side surface (Fig. 5 and Fig. 6). This design of the grate reduces the cost of its manufacture.

The smallest width of the grooves In (Fig. 1) should be equal to or less than the particle size of the calcined metallurgical raw materials, for example, the diameter of the pellets. Particles of metallurgical raw materials (except for pellets) have an irregular geometric shape, therefore, when calculating the smallest groove width, the size of the minimum side of the particles (for example, the smallest side of the box) is used. For pellets, its diameter is used. However, in any metallurgical raw material there is always an insignificant amount of particles with sizes less than the established standard values, including pellets with a diameter less than that established by the technological process of their manufacture. Such particles wake up in slots down under the bogie of the roasting machine. With fixed particle sizes of metallurgical raw materials and the diameter of the pellets, the gap between the grates with grooves should be reduced taking into account the increase in clearance in front of the grooves. The gap between adjacent grates is regulated by the total height G of the distance bars 3 (FIG. 1, FIG. 2) or by the sum of the incomplete height of the distance bars 4 located opposite each other on adjacent grates (FIG. 1, FIG. 2).

There are three options for placing the grooves of one grate with respect to the location of the grooves on the adjacent grate: the grooves 9 of one grate are located opposite the grooves 9 of the neighboring grate (Fig. 7); the grooves 9 of one grate are located opposite the gaps between the grooves 9 of the adjacent grate (Fig. 8); the grooves 9 of one grate with respect to the grooves 9 of the adjacent grate (Fig. 9) are located in an intermediate position between the two above positions.

Taking into account the selected mutual arrangement of the grooves on the neighboring grates, the gap between them, and therefore the total height of the distance bars, is calculated by the formula derived by solving the corresponding geometric problem.

For the above three options for the mutual placement of grooves on adjacent grates, the total height G of the distance bar 3 (Fig. 2) is determined by the following formulas:

where G ₁ and G ₂ - the total height of the distance bar;

D is the particle size of metallurgical raw materials, which determines the gap between the grid-irons (for bodies of irregular geometric shape, this value is determined experimentally, since it depends on the number of fractions of particles whose minimum transverse size fits into the gap formed by the grooves and the part of the gap between the grid-irons attached to it; for pellets, this is the diameter of the pellets);

In - the smallest width of the grooves (Fig. 1);

r is the radius of curvature of the corners of the groove (Fig. 7, Fig. 8, Fig. 9).

Formula (3) corresponds to the position at which the grooves on the adjacent grate are opposite each other (Fig. 7);

Formula (4) corresponds to the position at which the grooves of one grate are opposite the gap between the grooves of the neighboring grate (Fig. 8);

For the position shown in FIG. 9, in which the grooves 9 of one grate with respect to the grooves of the adjacent grate are located in an intermediate position between the positions corresponding to FIG. 7 and FIG. 8. The total height G _{3 of the} distance bar is selected intermediate between the values of G ₁ and G ₂ .

The proposed grate works as follows.

Grid-irons are installed in the trolley in accordance with the chosen variant of the mutual arrangement of the grooves. The grates installed in the trolley move through the technological zones of the roasting machine. A layer of pellets made from iron ore concentrate is loaded on top of their working surface. On both side surfaces from the working surface to the lower surface along the direction of movement of the heat-carrying gas of all grates, grooves are made.

When implementing the invention, when the grooves of each grate were located opposite the gap between the grooves of the neighboring grate, the width of the grooves at the level of the upper surface was 13% less than the diameter of the pellets. In the direction of the lower surface, the width of the grooves increases, and their length is approximately two times less than the width of the side surface. The total number of grooves in one gap between adjacent grates is 14 pieces. Due to this, the gap area increases by 12%, which solves the problem - it increases the flow of heat-carrying gas also by about 12%. An increase in the flow of heat-carrying gas proportionally accelerates the process of firing the pellets, which allows to increase the productivity of the firing machine by increasing the speed of the carts or increasing the thickness of the layer of pellets. Thus, a technical result is achieved in the proposed technical solution.

Claims (6)

1. The grate of the roasting machine containing the upper and lower supporting horns, spacer bars, a working fluid formed by the upper working surface, lower surface and side surfaces, characterized in that at least on one side surface from the upper working surface to the lower surface along the direction The movement of the heat-carrying gas is made grooves, the smallest width of which is equal to or less than the particle size of the calcined metallurgical raw materials. 2. The grate of the roasting machine according to claim 1, characterized in that the length of the grooves is equal to the width of the side surface at the place of their execution. 3. The grate of the roasting machine according to claim 1, characterized in that the length of the grooves is less than the width of the side surface at the place of their execution. 4. The grate of the roasting machine according to claim 1, characterized in that the grooves are made on both side surfaces of the grate. 5. The grate of the roasting machine according to claim 1, characterized in that the grooves are expanded in the direction from the upper working surface to the lower surface. 6. The grate of the roasting machine according to claim 1, characterized in that the grooves in the direction from the upper working surface to the lower surface have the same width.

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