UA86267C2 - unbalanced-throw screen - Google Patents

Abstract

The invention relates to mineral processing, namely to the vibration unbalanced-throw screens, and it can be used for sifting and dehydration of solid materials in construction, mining and other branches of industry. An unbalanced-throw screen contains a vibroinsulated duct with a sieve and vibration exciters installed on the duct in pairs, in the case one pair of vibration exciters is fixed on the duct rigidly, and another pair- with possibility of turning relative to the horizontal transverse axis, which penetrates the center of weight of the screen. The vibration exciters are made with possibility of control of frequencies of rotation in pairs. The invention provides for possibility of operational adjustment of the dynamic characteristics of screen, which makes it possible to operationally control displacement of the particles of material over the sieve for increasing efficiency of sifting and dehydration of solid materials.

Description

the achieved result (providing the ability to quickly adjust the dynamic characteristics of the sieve, which allows you to quickly control the movement of material particles along the sieve to increase the efficiency of sieving and dewatering of solid materials), is expressed as follows.

Installation of vibration exciters on the box in pairs with fixing of one of the pairs with the possibility of turning relative to the horizontal transverse axis that passes through the center of gravity of the screen allows changing the angle of action and the module of the total exciting force from the vibration exciters, which ensures a change in the shape of the vibration trajectories of the box in the vertical longitudinal plane and, as a result, changing the speed of movement of the material on the sieve screen. At the same time, the location of the axis of rotation of the vibrators in the center of gravity of the screen allows to eliminate the parasitic oscillations of the box (galloping) in the vertical longitudinal plane, due to the absence of an exciting moment of force. Thus, the ability to adjust the angle of rotation of the vibrators relative to the horizontal transverse axis, which passes through the center of gravity of the screen, allows you to quickly adjust the dynamic parameters of the machine to optimal values depending on the characteristics of the source material, which ensures an increase in the efficiency of sieving and dewatering.

Performance of vibration exciters with the possibility of adjusting the frequency of rotation in pairs allows to ensure a mode in which the screen box will oscillate according to the biharmonic law, which is characterized by a high level of alternating sign accelerations. In this case, the vibration trajectories of the screen box will be significantly different from rectilinear ones. Alternating loads, affecting the processed material located on the sieve, intensively loosen it, creating conditions for better passage of water during dehydration or fine particles during sieving in the under-sieve zone, thereby increasing the efficiency of the process of distribution of especially fine and small fractions.

The listed design features of the proposed technical solution provide the ability to quickly adjust the dynamic characteristics of the sieve, which allows you to quickly control the movement of material particles through the sieve to increase the efficiency of sieving and dewatering of solid materials.

Below is a detailed description of the design of the claimed inertial screen, with a description of its operation and with references to the drawings, which show:

Fig. 1 - inertia screen, general view.

Fig. 2 - inertia screen, top view.

Fig. 3 - an inertial screen, a node of attachment of mobile vibrators.

The inertia screen includes a box 1 with a sieve 2 (Fig. 1), which consists of sidewalls C (Fig. 2), connected to each other by transverse connecting beams 4 (Fig. 1) and a subvibrator beam 5 (Fig. 2) . On the opposite sides of the sub-vibrator beam 5, the first pair of vibrators 6 is firmly and fixedly installed (Fig. 1). In the places of attachment of the middle connecting beam 4 with the side walls of the box 1, plates 7 with a pin 8 are fixed (Fig. 3). The mounting plate 9 of the second pair of vibration exciters 10 is installed on the trunnion 8 with the possibility of its rotation relative to the trunnion 8 (Fig. 3). Vibration exciters 6 and 10 are made in the form of motor-vibrators. Fixation of the mounting plate 9 relative to the trunnion 8 is performed with the help of a retainer 11, and to control the angle of rotation of the mounting plate 9 relative to the trunnion 8, an angle scale 12 is provided (Fig. 3). Frequency converters (not shown in the figure) are installed to adjust the frequency of rotation of vibrators 6.

Inertia screening works like this. In the operating mode, the exciting force from the vibrators 6 and 10 is transmitted to the box 1, causing it to oscillate in the vertical longitudinal plane along the x axis. The oscillations of the box 1 are transmitted to the sieve 2 rigidly attached to the box 1 and the material on it, as a result of which the material moves from the loading zone to the screening unloading zone. When changing the technological characteristics of the material being processed (for example, the final distribution size, particle size composition, humidity, etc.), the dynamic parameters of the machine are adjusted to optimal values. To do this, the vibrator 10 is rotated to an angle y relative to the x axis, performing the following operations: release the latch 11, turn the mounting plates 9 on the pins 8 with the vibrators 10 fixed on the plates 9 to the required angle y, and then tighten the latches 11. The rotation angle y is controlled by scale 12. At the same time, the location of the axis of rotation of the vibrators 10 in the center of gravity of the screen allows to eliminate parasitic vibrations of the box (galloping) in the vertical longitudinal plane, due to the absence of an exciting moment of force. Changing the turning angle of the vibrators 10 allows you to change the angle of action and the module of the total exciting force from the vibrators 6 and 10, and, therefore, to adjust the speed of movement of the material through the sieve 2 and its looseness. The possibility of free access to the latches 11, good visibility of the scale 12 with the simplicity of operations to change the angle of rotation of the vibrators 10 allow you to quickly adjust the screen to the optimal operating mode depending on the characteristics of the source material. The consequence of this is an increase in the efficiency of sieving and dehydration of the material.

Regulation of the frequency of rotation of vibrators b and 10 can be carried out, for example, with the help of a frequency converter (inverter) of the supply voltage. When setting vibration exciters 6 and 10 to different rotation frequencies, box 1 will oscillate according to the biharmonic law. In this case, the trajectories of box 1 oscillations will be significantly different from rectilinear ones. Alternating loads, affecting the processed material located on sieve 2, intensively loosen it, creating conditions for better passage of water during dehydration or fine particles during sieving into the sub-sieve zone, thereby increasing the efficiency of the process of distribution of especially fine and small fractions.

In the inertial screen, it is also possible to adjust the static moments of the masses of vibrators 10 by one of the traditional methods, for example, by changing the mass of the imbalances (using variable loads), changing the distance from their center of gravity to the axis of rotation (eccentricity of the imbalances), or a combination of these two methods.

By changing the ratio of the rotation frequencies of the vibrating exciters, the values of the static moments of the masses of each pair of vibrating exciters and the phase shift angle between them, it is possible to obtain various biharmonic vibrations of the screening box, optimizing them for solving specific technological problems.

Thus, the design of the inertial sieve, which is claimed, provides the ability to quickly adjust the dynamic characteristics of the sieve, which allows you to quickly control the movement of material particles on the sieve to increase the efficiency of sieving and dewatering of solid materials. : 5 7 xx 10 1 4 2 o. «| and

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