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§ 2.2 Theoretical study of the effect of the moving mesh surface of the separator on the cotton piece.
One of the most important issues in the working chamber of the separator, in the process of separating the cotton from the air stream, is to eliminate the impact on the cotton between the mesh surface and the scraper, to prevent damage and at the same time reduce fiber loss and increase cotton efficiency.
Theoretical research has been conducted on the improvement of the separator device, which increases the efficiency of the separation process, overcoming the above existing shortcomings.
Figure 2.10 The proposed cotton separator device
1 inlet pipe, 2 working chamber, 3 guide, 4 mesh surface conveyor, 5 set, 6 shafts, 7 brush drum, 8 vacuum valve, 9 air suction pipe.
The cotton pieces that enter the separator working chamber along with the air flow are hit by a mesh conveyor belt that forms an angle with the vertical direction (Figure 2.11). The cotton pieces move down the surface of the net, due to their gravitational force. A certain part of the air flow is sucked through the cracks in the mesh surface in its direction. The mesh surface is in the form of a conveyor belt that moves regularly. In the process of separating the cotton pieces from the air, they move along the surface of the net, sticking to it. After the mesh surface and the cotton raw material have traveled a certain distance, the cotton raw material is separated from the mesh surface using a brush drum located at the bottom. The separated cotton raw material is thrown to the bottom of the device and from there it is discharged through a vacuum valve. Cleaning of passive contaminants from raw cotton as a result of air absorption from the surface of the net when the raw cotton sticks to the surface of the net process occurs. In this process, the angle formed by the vertical direction of the plane of the mesh surface will also have an effect on the process of separation of cotton pieces from the air.
Figure 2.11. Interaction of cotton with a moving mesh surface
The process of separation, in which it is important to study the laws of motion of cotton pieces along the surface of the net [72].
The forces acting on the movement of the cotton pieces in the separator working chamber along the mesh surface are as follows (Figure 2.12).
Figure 2.12. Forces acting on the movement of cotton pieces along the mesh surface The forces influencing the movement of cotton pieces along the mesh surface are as follows
- aerodynamic lifting force;
- aerodynamic pressure force;
- gravity of a piece of cotton;
- friction force between the cotton piece and the mesh surface;
- coefficient of friction;
- dragging force of cotton by a mesh surface conveyor belt;
We calculate the projections of the forces acting on a piece of cotton on the axes and axes:
or:
If we enter the designation as follows:
(2.9)
The projections of all the forces acting on a piece of cotton on the axes and axes are as follows:
(2.10)
In this case, we write the differential equations of motion of cotton pieces along the mesh surface as follows:
(2.11)
Where: m is the mass of the cotton piece;
(2.11) - The system of differential equations is integrated under the following initial conditions (2.12) and obtained from the graphs in Figure 2.13 2.18 on the basis of the MAPLE-17 program.
Prerequisites:
(2.12)
Analysis of the results: The graphs in Figures 2.13, –2.14 show the laws of change of the laws of motion of cotton pieces in the horizontal - axis and vertical direction in time - t. As can be seen from the graphs in Figure 2.13, the process of separating the cotton pieces from the mesh surface accelerates as the angle of inclination, which forms the surface of the mesh conveyor in a vertical direction, increases. In particular, if the cotton pieces separate from the mesh surface at t = 0.14 sec and continue to move in the vertical direction and move on to the next process, this process will occur at t = 0.12 sec.
This, in turn, separates the air from the cotton pieces and accelerates the separation process.
Figure 2.13. The movement of a piece of cotton in the OX-coordinate direction over time, the law of change at different angles.
1), 2), 3), 4).
Figure 2.14. The movement of a piece of cotton in the OU-coordinate direction over time, the law of change at different angles.
1), 2), 3), 4).
The graphs in Figure 2.15 show the law of variation of the movement of a piece of cotton in the vertical ou - direction depending on the horizontal axis - direction. When a conveyor belt surface has a vertical deflection angle,
although the piece of cotton separates from the mesh surface and moves on to the next process
As long as this process happens. That is, increasing the angle accelerates the process of separation of cotton pieces from the air.
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