UA63539A - Method for screening materials - Google Patents

Abstract

A method for screening materials which consists in the feed of the material into vertical channel in which are arranged in zigzag fashion each under other the vibroexciter grates located on two vertical sections exposed to forced dynamic action, thus the screening process is carried out due to cumulative influence of kinetic energy of the material flow, energy of forced oscillations of grates and energy of vibrational excitations of the grates. Forced dynamic influence is performed separately on each section with various fixed frequency of oscillation in resonant and more than resonant modes. The change of frequency of forced dynamic influence on each section is made successively and synchronously on both sections.

Description

Description of the invention

The invention relates to the distribution of materials using sieves and can be used in the metallurgical, mining, and chemical industries.

A known method of screening materials (Patent of Ukraine Мо44592А, МПК7 ВО0О781/00, 15.02.2002), which includes cyclic feeding of the material onto the grating vibration-exciting sieving surfaces located one below the other, vibrational movement of the material through them due to the use of the material's gravitational forces, that falls, and partial sieving of sub-grating fractions on each sieving surface, 70 The disadvantage of the known method is the insufficient efficiency of the screening process of wet finely fractionated materials with the advantage of sub-grating fractions, where the gravitational forces of the falling material do not lead to effective vibration excitation of the sieving surfaces, but the use of a high frequency of cyclic feeding of material on the sieving surface leads to smoothing of dynamic impacts of portions of material against elastic grates. In addition, with insufficient vibration excitation of the sieving surfaces, the self-cleaning of 72 sieves deteriorates, which leads to a deterioration in the quality of screening.

The closest technical solution chosen /as a prototype/ is the method of screening materials (Patent

of Ukraine Мо49714А, МПК7 В8О0781/28, 16.09.2002), in which the material is fed into a vertical channel where vibration-excited grates are installed in a zigzag manner under one another, located on two vertical sections, on which they exert a forced dynamic influence with a frequency equal to the frequency of the grates' own vibrations , while the screening process is carried out due to the combined effect of the kinetic energy of the material flow, the energy of the forced vibrations of the grates and the energy of the vibration excitations of the grates.

The disadvantage of the known method is insufficient screening efficiency of wet, finely fractionated materials prone to sticking, where the resonant frequency of vibration of the grates is not sufficient for their effective vibration excitation and cleaning from sticking. In addition, the use of only the resonant frequency of forced 22 dynamic influence reduces the reliability of the equipment. "

The invention is based on the following tasks: - improving the screening quality of wet finely fractionated materials; - increasing the productivity of the screening process; - increasing the reliability of the equipment. Me.

In the proposed invention, these problems are solved with the help of the fact that in the method of screening materials, which includes feeding the material into a vertical channel where vibrationally excited grates are installed in a zigzag manner under one another, located on two vertical sections, which exert a forced dynamic influence, while the process screening is carried out due to the combined effect of kinetic energy from the flow of material, energy of forced vibrations of grates and energy of vibration excitations of grates, in accordance with the invention, forced dynamic impact is carried out separately on each section with a different fixed frequency of oscillation in resonant and more than resonant modes, while changing the frequency of forced dynamic influence on each section is carried out sequentially and synchronously on two sections once with the same terms. In addition, forced dynamic influence on sections in a more than resonant mode is carried out with a frequency of oscillations equal to 1.5-2.0 of the resonance frequency of vibrations of the grates. Also, with 50, the forced dynamic impact on the vibrating grates of each section is carried out in the resonant and more than resonant modes consecutively with the same time, which is 1-2 minutes. c" Comparison of the proposed method with the prototype shows that the new thing is the implementation of forced dynamic influence, separately on each section with a different fixed frequency of oscillation in resonant and more than resonant modes, while changing the frequency of forced dynamic influence on each section is carried out sequentially and synchronously on two sections once with the same terms. b The section with grates, which oscillates with a resonant frequency, more effectively performs the sorting of the material with the required productivity. The second section with grates, which oscillates with more than a resonant frequency, more effectively cleans the sieving surface from the sticking of wet fine fraction and materials. When moving the sorted material between grates, one of which oscillates in resonance

Ge) 20 mode, and the second sieve oscillates in a more than resonant mode, more effective movement of material is ensured due to the braking of individual layers of material, which increases the quality and productivity of screening. Changing the frequency of forced impact on each section sequentially and synchronously with a period of 1-2 minutes leads to ensuring uniform loading of equipment nodes and increasing its reliability. 29 In fig. the schematic diagram of the screen design, which implements the proposed method, is shown. in. The screen contains a receiving hopper with a loading device 1, a vertical channel 2, which is formed by two vertical removable sections 3, each of which consists of two springs fixed at the edges in the lower part, connected to each other by several inclined deflectors 5 with fixed on them vibration excited grates 4, which are placed one under the other, with a step in the vertical plane equal to 60 times the oscillation period of the sinusoidal curve of the vertical channel 2.

At the same time, the concave surfaces of the grates 4 of each section C are directed toward the axis of the vertical channel and are offset relative to each other in the horizontal plane by an amount equal to half the oscillation period of the indicated sinusoidal curve. Sections C in their middle part are connected to sources of forced oscillations 9.

Regulation of the size of the passage section of the channel is carried out by changing the angle of inclination of each section Z bo relative to their vertical position by changing the length of stabilizers 8.

Deflectors 5 are made in the form of cantilever-fixed vibration-exciting inclined rectangular sheets, on which vibration-exciting grates 4 are located.

The screen also contains channels for moving sub-grating fractions b, nozzles for the output of distributed fractions 7.

Screening work is carried out as follows:

The material to be sorted is fed into the receiving hopper with the loading device 1, where it moves under the action of its own weight along the vertical channel 2, which is formed by two vertical removable sections 3, each of which consists of two springs fixed at the edges in the lower parts, connected /0 to each other by several inclined deflectors 5 with vibrating grates 4 attached to them. Forced vibration sources 9 transmit forced dynamic influence separately to each section with a different fixed frequency of oscillation in resonant and more resonant modes, while changing the frequency of forced dynamic influence on each section is carried out sequentially and synchronously on two sections once with the same terms, which is 1-2 minutes. As a result of the dynamic effect of the vibrating /5 grates on the flow of material moving along the vertical channel 2, particles of material that are smaller in size, from the gaps of the screening surface, pass through the sieving surface of the grates 4 and, under the action of their own weight, move along the exit surfaces of the deflectors 5 to the nozzles for output of distributed fractions 7. Particles of material that are larger in size than the gaps of the sieving surface, as well as particles of the fine fraction that did not have time to be removed on the first sieving surface, enter the next ones, where the described process of 2o Gfiltration is repeated. The number of sieves with 4 screening surfaces depends on the desired screening quality and its initial fractional composition. Large particles of material, passing under the influence of their own weight through the vertical channel 2 of the screen, interact with all the surfaces of the sieve screens 4 and go to the nozzles for the output of the distributed fractions 7.

The use of the proposed method for sieving materials allows for effective sorting of wet finely fractionated materials with a content of more than 9095 fractions, while the sieving productivity increases by 3 times and the probability of cluttering the sieving surfaces with small fractions decreases. The method for sieving materials can be obtained by modernizing the sieving machines available at enterprises of the metallurgical, mining, and chemical industries.

Claims (2)

The formula of the invention so , c, , - , iv) 1. The method of screening materials, in which the material is fed into a vertical channel, in which vibrating grates are installed in a zigzag manner, one under the other, located on two vertical sections, on which the co exerts a forced dynamic influence, while the screening process is carried out due to the cumulative "co influence of the kinetic energy of the material flow, the energy of forced vibrations of grates and the energy of vibration excitations of grates, which is characterized by the fact that the forced dynamic influence is carried out separately on each section with a different fixed frequency of oscillation in resonant and more than resonant modes, while changing the frequency of forced dynamic influence on each section are carried out sequentially and synchronously on « 70 two sections at once with the same deadlines. w-in the village 2. The method according to claim 1, which differs in that the forced dynamic influence on the sections in a more than resonant mode is carried out with an oscillation frequency equal to 1.5-2.0 of the resonance frequency of oscillations from the grates. Q. The method according to claim 1, which differs in that the forced dynamic impact on the vibrating grates of each section is carried out in resonant and more than resonant modes in sequence with the same FD terms of 1-2 minutes. (95) 1 o 50 3e) P 60 b5