RU2648701C2 - Method for disintegration of brittle materials and a rotor disintegrator - Google Patents

Abstract

FIELD: desintegrators and crushing devices.

SUBSTANCE: group of inventions relates to devices for crushing materials and can be used for grinding brittle materials. Method for disintegration of brittle materials comprises feeding the material directly to a rotating drum installed in the precipitation chamber, wherein the material is lifted along the inner surface of said drum and impacted thereon after the material is separated from the inner surface of the drum by means of a working member. Working member in the form of a rotor with hammers rotates at a speed that is the maximum permissible according to the strength of its elements in the field of centrifugal forces. Pneumatic unloading is carried out in the precipitation chamber. Rotor disintegrator comprises a drum and a rotor installed inside it. Drum, located inside the precipitation chamber, with lifters on the inner surface and the rotor with hammers are mounted with the possibility of opposing rotation. Drum is provided with a loading cone at one end and with an open second end, and the precipitation chamber is equipped with a pneumatic blower for circulating air within the precipitation chamber through the drum.

EFFECT: group of inventions allows to exclude the necessity of using active dust collectors and filters during pneumatic unloading of the product.

3 cl, 3 dwg

Description

The invention relates to the field of fine grinding of brittle materials.

Known and adopted as a prototype method for the disintegration of rocks and a rotary mill for its implementation [1].

The method of disintegration of rocks includes feeding the material into a rotating drum, lifting it along the inner surface of the drum and pneumatic unloading. Pieces of material after being detached from the inner surface of the drum are subjected to impact by a working body coaxially mounted on the hollow shaft in the drum with the possibility of opposite rotation with a speed equal to 85-92% of the critical one, while pneumatic unloading of the material is carried out through the openings of the hollow shaft.

The rotary mill for implementing the method comprises a rotatably mounted drum with lifters on the inner surface and devices for loading and pneumatically unloading the material. A rotor with beats is mounted coaxially on the hollow shaft inside the drum, with the possibility of opposite rotation with a speed equal to 85-92% of the critical speed, while the rotor shaft is made with holes for pneumatic unloading of the material, and screw spirals are mounted in its cavity for feeding the material and unloading it large fractions.

The idea is that multiple impacts on particles of material that continuously circulates in the range of beat of the rotor by means of a drum with lifters rotating at a subcritical speed are rational and potentially effective.

Consider now the proposed technical solution to this idea.

The source material is fed into the hollow shaft of the rotor and, according to the author, is transported to the transverse through hole in the middle of the rotor by a conveying pipe (helical spiral on the inner surface of the hollow shaft), rotating at a speed equal to 85-92% of the critical value for the inner diameter of the shaft. The conveying pipes are operable only under the condition of continuous sliding of the material relative to the spiral, and at a rotation speed of 85-92% of the critical value for the inner diameter of the conveying pipe, the material is pressed by centrifugal force to the inner surface of the pipe and only in its upper part, where the gravity exceeds the centrifugal force, material falls down. The sliding of the material relative to the screw is practically zero. To move it, you need a rotation speed of less than 30% of the critical. Thus, the claimed essential feature (speed of rotation) virtually eliminates the flow of material into the drum. This is their first fundamental flaw.

Let's say that the material got inside the drum. We estimate the impact in numbers. Suppose that the inner diameter of the hollow shaft is one meter, and the diameter of the working surfaces of the rotor beat is 1.6 m. At 92% of the critical speed of the hollow shaft, its angular velocity is 4.25 s ^-1 and the peripheral speed of beat is 3.4 m / s. At such an impact speed, only very loose materials are crushed, and grinding to a dust fraction for pneumatic discharge by suction through the second end of the hollow shaft, as indicated in the description, is absolutely unrealistic. This is the second fundamental disadvantage of the method and device.

The third significant drawback of the device is pneumatic unloading through the second end of the hollow shaft of the rotor by suction (indicated in the description) requires a set of equipment to isolate the product from the suction air-dust stream - a battery of cyclones and bag filters, as well as powerful (taking into account the aerodynamic resistance of the mill and these devices ) exhauster. And even with such a set of dust-collecting equipment, about 2% of the dust (the finest and most valuable fraction) is not captured and goes into the environment.

The objective of the invention is the execution of the operations of loading the source material into the drum and rotor rotation by not interconnected mechanisms, eliminating the need for active dust collectors and filters during pneumatic unloading of the product.

The problem is solved due to the fact that in the method of disintegration of brittle materials, including feeding the material into the rotating drum, lifting it along the inner surface of the drum, impact after separation from the inner surface of the drum by a working body installed in the drum with the possibility of opposite rotation and pneumatic unloading, according to the invention, the source material is loaded directly into the drum, the working body in the form of a rotor with a beater is rotated at a speed maximum permissible by the strength conditions of the ele rotor cops in the field of centrifugal forces, and pneumatic unloading is carried out in a precipitation chamber, inside of which there is a drum with a working body.

In a rotary disintegrator for implementing the method, comprising a rotatably mounted drum with lifters on the inner surface and a rotor with beater installed inside the drum with the possibility of opposite rotation, according to a utility model, the drum is located inside the settling chamber, made with a loading cone at one end and with an open second but the precipitation chamber is equipped with a pneumatic discharge device, such as a fan, for air circulation inside the precipitation chamber cut drum.

In addition, the drum shell is gas-permeable, the working surfaces of the drum and the beater are protected by an easily replaceable impact-resistant and abrasion-resistant lining, the beats have a length equal to or a fraction of the length of the rotor, and are fixed to it rigidly or articulated, a tray is installed at the open end of the drum for outputting incompletely crushed / crushed particles from the sedimentation chamber.

The loading of the source material not through the hollow shaft of the rotor, as in the prototype, but directly into the drum, allows the rotor to rotate at any given speed, the higher the peripheral speed beat the rotor and, accordingly, the speed of impact, the higher the grinding performance and the smaller the average particle size of the product. But with an increase in the rotation speed sharply (in proportion to the square of the angular velocity), the centrifugal forces increase, causing stresses in the bars, in the elements of their fastenings, in the rotor disks. In this regard, the rotation speed is limited by the maximum permissible stresses in the most dangerous rotor assemblies. Placing a drum with a rotor inside the sedimentation chamber eliminates the need for cyclones, filters and other dust-collecting equipment, which simplifies the unit, reduces its cost and emissions into the environment. The execution of the drum with the loading cone at one end significantly simplifies the introduction of the loading tray into the drum cavity and the flow of material to the lifters, and the open second end allows the dust fraction to be freely carried into the settling chamber by the air flow circulating through the drum due to the discharge device.

The dust deposition rate is significantly lower than the speed of the circulating stream, but the amount of dust deposited per unit time is proportional to the concentration of dust in the air. In a closed volume (in a sedimentation chamber), such a concentration of dust is established spontaneously at which, per unit time, the amount generated is equal to the amount removed from the bottom of the chamber. The rotor forms an intense vortex radial air flow inside the drum with increased pressure on the inner surface of the drum. The implementation of the gas-permeable shell allows you to carry out the dust fraction not only through the open end of the drum, but also through the shell, which, in turn, reduces the performance of the discharge device. The protection of the working surfaces of the drum and beaters by impact-resistant and abrasion-resistant lining increases the length of the overhaul life of the disintegrator, and the easily replaceable lining shortens the repair time.

The essence of the invention is illustrated by drawings, which depict:

FIG. 1 is a longitudinal section of a disintegrator.

FIG. 2 - section along aa.

FIG. 3 - a section along BB.

The drum 1 (Fig. 1, 3) of the disintegrator with lifters 2 and the loading cone 3 (Fig. 1, 2) is mounted on the rollers 4 (Fig. 1, 3) inside the settling chamber 5 (Fig. 1-3) with screw discharge 6 and with a blow channel 7 (FIG. 1, 2) equipped with a fan 8 (FIG. 1). Inside the drum 1 there is a rotor 9 (Fig. 1, 3) with beats 10. The rotor 9 is rotated by the drive 11 (Fig. 1) by means of a shaft 12 (Fig. 1-3), the second end of which is installed in a dustproof bearing 13 (Fig. 1 ) mounted on the racks 14 (Fig. 1, 3) to the case of the precipitation chamber 5. A hopper tray 15 is inserted into the loading cone 3 (Fig. 1, 2), an output tray 16 is installed at the open end of the drum 1 (Fig. 1, 3 ) The rollers 4 are driven into rotation by the shafts 17 (Fig. 1, 2) from one drive (not shown). The rotor 9 is equipped with a cowl 18 (Fig. 1). The deposition chamber 5 is mounted on elastic supports (not shown) with the possibility of adjusting the angle of inclination of the longitudinal axis to the horizontal.

The device operates as follows.

In the initial position, the precipitation chamber 5 is inclined towards the open end of the drum 1 by an angle of 2-3 °, the rollers 4 rotate the drum 1 clockwise in FIG. 2 at a speed of 85-90% of the critical speed, the rotor rotates counterclockwise at a peripheral speed of 100-150 m / s. The fan 8 drives air from the lower part of the precipitation chamber 5 through the blowing channel 7 through the loading cone 3 into the drum 1, the air stream flows around the rotor 9, is intensively turbulized by the beaters 10 and through the open end of the drum 1, as well as through its breathable shell, for example, of a louvre type, returns to the precipitation chamber.

When supplying the source material to the hopper 15, it by gravity moves to the loading cone 3 by gravity and enters the elevators 2, they rises to the upper part of the drum 1, falls along a parabolic path into the impact zone and is crushed. The dust fraction is picked up by the vortices of the air flow, additionally crushed as in a jet mill and carried away into the precipitation chamber 5, and larger particles are thrown onto the drum 1 and rise again. Due to the inclination of the drum with each rise, the circulating particles of the material gradually move towards the open end of the drum 1. The concentration of dust in the air stream increases to a certain constant value at which the formation of dust is equal to the deposition. The settled dust (product) is discharged by the screw 6. The supply of material is increased until the particles are not completely crushed at the outlet of the tray 16, then they are slightly reduced and stabilized. Imperishable particles, for example, kings of metal in the slag are discharged through the tray 16, regardless of the performance of the unit. The average particle size of the product is regulated by changing the inclination of the precipitation chamber 5 - the smaller the angle of inclination, the smaller the average particle size. When the rotor 9 is rotated and the material shocks, vibration will inevitably form, mainly transverse, of the precipitation chamber. Its elastic-elastic supports absorb vibration and maintain amplitude within acceptable limits.

The disintegrator is periodically stopped, the upper part of the precipitation chamber is removed, the worn lining is replaced with the restored one and put into operation, and the removed lining is fused with carbide electrodes.

Thus, in the proposed design, the operations of loading the source material into the drum and rotating the rotor by non-interconnected mechanisms, obtaining a product with a given fractional composition from any brittle materials, eliminates the need for active dust collectors and filters during pneumatic unloading of the product.

The source of information

1. The method of disintegration of rocks and a rotary mill for its implementation. RF patent No. 2185885 C2, IPC B02C 17/10. Publ. 07/27/2002. Bull. No. 20.

Claims (3)

1. The method of disintegration of brittle materials, including feeding material into a rotating drum, lifting it along the inner surface of the drum, impact after detaching from the inner surface of the drum by a working body installed in the drum with the possibility of opposite rotation, and pneumatic unloading, characterized in that the starting material load directly into the drum, the working body in the form of a rotor with bills rotate at a speed maximum permissible according to the strength conditions of its elements in the field of centrifugal systems And an air discharge is carried out in a settling chamber inside which is located a drum with a working body. 2. A rotary disintegrator for implementing the method, comprising a rotatably mounted drum with lifters on the inner surface and a rotor with beats installed inside the drum with the possibility of opposite rotation, characterized in that the drum is located inside the settling chamber, made with a loading cone at one end and open second end, and the precipitation chamber is equipped with a pneumatic discharge device, such as a fan, for circulating air inside the precipitation chamber through Araban. 3. The disintegrator according to claim 2, characterized in that the drum shell is gas-permeable, the working surfaces of the drum and the beaters are protected by an easily replaceable impact-resistant and abrasion-resistant lining, the beaters have a length equal to or a fraction of the length of the rotor, and are fixed to it rigidly or articulated at the open end a drum tray is installed to output incomplete / crushed particles from the sedimentation chamber.

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