RU2283697C2 - Grinding method in cone eccentric grinder - Google Patents

Abstract

FIELD: mean and fine grinding processes and equipment.

SUBSTANCE: method of grinding in cone eccentric grinder comprises steps of setting dimension of loading lit between grinding cones; driving grinder; loading grinding chamber with initial product; grinding it; determining fraction size of ground product and correcting dimension of loading slit for providing desired fraction size of ground product; at first setting dimension of loading slit equal to zero; then loading grinding chamber with initial material and driving grinder; increasing dimension of loading slit for achieving target efficiency of grinder. Desired faction size of ground product is provided due to regulating revolution number of drive eccentric.

EFFECT: improved grinding degree, enhanced efficiency, low specific power consumption.

2 dwg

Description

The invention relates to methods for medium and fine crushing in eccentric cone crushers and can be most widely used in the construction and mining and metallurgical industries.

To prepare a metal concentrate from ore, it is necessary to crush and grind a piece of more than 1 meter to particles smaller than 0.1 mm. Most often, 3-4 stages of crushing, consisting of eccentric cone crushers, are used for this purpose, followed by three stages of grinding in rod and ball mills.

As a result, almost 60% of all types of costs of mining enterprises absorb their crushing and grinding departments. In addition, the inevitable regrinding finer than 20 microns leads to almost 15% loss of metals.

In this regard, the transfer of the center of gravity of the disintegration process to the crushing compartments can significantly reduce the mentioned costs and losses.

The crushing methods in existing eccentric crushers have not changed since they were created in 1878. As before, the compression ratio of the material layer in the crushing cavity is limited by the drive eccentric, therefore the internal movable cone cannot have an oscillation amplitude different from the drive eccentricity. Hence, the degree of crushing does not exceed the value of 6 ÷ 7.

In traditional eccentric crushers it is impossible to increase the number of revolutions of the eccentric, as this leads to an imbalance of the system and slipping of the cone from the spherical support.

Thus, the technological capabilities of eccentric crushers are almost exhausted and the efforts of designers are mainly aimed at improving the reliability of crusher assemblies and improving its automatic control system.

A known method of intensifying the work of an eccentric crusher, implemented in a device (AS USSR No. 580895 of 07/09/1974), in which the drive element is made in the form of a lever, the ends of which are placed in the eccentric and in the body of the cone, and the support is in the housing crushers. This gives a twofold increase in crushing force, which increases the degree of crushing to 7 ÷ 8, but still does not provide a controlled degree of compression of the material layer and limits the further increase in technological parameters.

There is also a method of increasing the technological parameters of an eccentric crusher (USSR AS No. 625770 dated 04/25/1977), which includes idling the crusher, reducing the size of the discharge gap to the first touch with the inner cone, fixing the achieved size of the gap and loading the crusher with mineral. The method allows to achieve the minimum allowable size of the discharge gap due to the fact that in the eccentric assembly at idle, all radial clearances (total of about 4 mm) are selected by pressing the cone shaft by centrifugal force on the surface of the eccentric, and the eccentric on the cylindrical sleeve. This method allows you to raise the degree of crushing to 7 ÷ 8. However, a greater effect in the known eccentric crushers while maintaining the generally accepted principle of operation of the eccentric assembly is already impossible to achieve.

Known for the prototype method of crushing minerals, carried out in a cone eccentric crusher with hydraulic adjustment of the position of the inner cone in height and size of the discharge gap (US patent No. 3456889 from 04/10/1967, 02 C).

The method includes installing an unloading gap between the crushing cones, starting up the crusher, loading the crushing chamber with the initial mineral, crushing it, determining the size of the crushing product and adjusting the size of the gap to obtain the desired size of the product.

As in the previous analogue, the known method involves the difficulty of setting an accurate and possibly small gap in order to obtain the maximum degree of crushing.

This method, like the previous one, does not make it possible to increase the degree of crushing more than 7 ÷ 8.

The aim of the proposed method is to reduce the stages of crushing and grinding by combining at least two of them in one unit by increasing the degree of crushing.

The objective of the method is the organization of such a sequence of operations and the introduction of new operations that provide a high degree of crushing with increased productivity and reduced specific energy consumption.

The problem is solved in that in the proposed method, including setting the size of the discharge gap between the crushing cones, starting up the crusher, loading the crushing chamber with the source material, crushing it, determining the size of the crushing product and adjusting the size of the discharge gap to obtain the required size of the finished product, in accordance with by the present invention, first, the size of the discharge gap is set to zero, then the crushing chamber is loaded with the starting material, then the crusher is started, after then the size of the discharge gap is increased to achieve the required performance, and the required fineness of the finished product is obtained by adjusting the speed of the drive eccentric.

The method can be implemented in a conical eccentric crusher.

Figure 1 shows the aforementioned crusher in longitudinal section in a static state.

Figure 2 shows the working part of the crusher in one of the operating conditions.

The term "discharge gap" will be understood as the sum of the radial distances between the bases of the inner and outer cones (position 11 of figure 1 and 2).

Before starting the operation of the unit, the size of the discharge gap (11) is set equal to zero. This makes it possible to load the crushing chamber with raw material that will not wake up through the crusher without treatment. After loading, the crusher is started, as from the prior art it is known that the operation of the crushing unit at idle is undesirable - the friction of the cones against each other leads to their premature wear. Then, the required size of the discharge gap is established (11), taking into account the fact that the larger the size of the discharge gap, the larger the throughput cross section of the crushing chamber, the higher the productivity of the crushing process. At the same time, such an important parameter as the fineness of the finished product is controlled by adjusting the speed of the eccentric: by changing this parameter, you can adjust the value of the crushing force and the frequency of application of force.

In contrast to the proposed technical solution, in similar methods, the initial (starting) size of the discharge gap is chosen significantly larger than is required technologically. This is done in order to reduce the load on the eccentric drive (8) when filling the crushing chamber with the starting material. The crusher is started at idle, then the source material is loaded, then the size of the discharge gap (11) is reduced to the required or minimum possible, depending on the required size of the finished product.

The design of the eccentric crusher is shown in figure 1.

The crusher contains a housing (1) with an external crushing cone (2), inside of which there is an internal crushing cone (3), the shaft (4) of which is supported through a spherical support (5) (consisting of a heel and a thrust bearing) on the piston (6) of the hydraulic cylinder ( 7) located in the housing (1). An eccentric (8) mounted on the shaft (4) is mounted for rotation relative to it, mounted inside the cylindrical bearing sleeve (9) with a radial clearance (10) exceeding the size of the discharge gap (11) between the cones (2) and (3).

The cylindrical sleeve (9) is coupled to an electric motor (14) through a gear pair (13).

The upper part of the shaft (4) is placed by means of a hinge (15) in the traverse (16). The drive element (12) is rigidly fixed on one side to the cylindrical sleeve (9), and, on the other hand, is inserted into the groove (17) of the eccentric (8).

Crusher works as follows.

From the electric motor (14), the torque is transmitted through the gear pair (13) to the cylindrical sleeve (9), which rotates the eccentric (8) through the system of the drive element (12) inserted into the groove (17). The latter develops centrifugal force and involves the inner cone (3) in circular oscillations. The cone (3) also acquires a centrifugal force, which is combined with the centrifugal force of the eccentric into a crushing force, due to which intralayer destruction of the starting material in the cavity formed by crushing cones is carried out.

Due to the implementation of the claimed sequence of operations, the degree of crushing of the crusher can be adjusted in the range from 4 to 30. That is, it is possible to obtain 100% of the product smaller than 20 mm or smaller than 5 mm from the same starting piece, for example, 100 mm.

Thus, the method allows you to replace the stage of fine crushing and the first stage of grinding, for example a core mill, i.e. ensures the full implementation of the task.

Claims (1)

A crushing method in a cone eccentric crusher, including setting the size of the discharge gap between the crushing cones, starting up the crusher, loading the crushing chamber with the source material, crushing it, determining the size of the crushing product and adjusting the size of the discharge gap to obtain the desired size of the product, characterized in that the size of the discharge first the slots are set to zero, then the crushing chamber is loaded with the starting material and the crusher is started, after which the size of the discharge chamber is increased ate to achieve the desired performance crusher, and the desired size of the crushed product obtained by adjusting the speed of the drive cam.

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