RESULTS OF THEORETICAL RESEARCH ON THE IMPROVEMENT OF TECHNOLOGICAL EQUIPMENT FOR CLEANING FIBER DEAD

ABSTRACT

This article discusses descriptions of a technical solution and the results of theoretical studies of its technological process selected on the basis of analytical studies of known developments of equipment for the purification of fibrous waste that is released during the process of ginning cotton and cleaning fiber.

АННОТАЦИЯ

В статье рассмотрены описания технического решения и результаты теоретических исследований его технологического процесса, выбранные на основе аналитических исследований известных разработок оборудования для очистки волокнистых отходов, выделяющихся в процессе джинирования хлопка и очистки волокна.

Keywords: fibrous uluc, cleaning, improved, equation, friction force, coagulation angle, efficiency, pinning auger.

Ключевые слова: волокнистый улук, очистка, улучшенное, уравнение, сила трения, угол коагуляции, эффективность, закрепляющий шнек.

Introduction. The main products in the technological process of initial processing of cotton are cotton fiber, cotton seed and fluff, in addition a large amount of fibrous waste is obtained. (Gin dead, linter dead, fine fiber pieces and ginning equipment dead), their processing produces fibrous materials suitable as raw materials for textile and other industries [1].

Rieter of Europe (Switzerland); Trutzschler (Germany); Companies such as Marzoli (Italy) [2] offer equipment systems for the processing of fibrous waste and low grade cotton. The cleaning effect of these systems is high, because they use needle, saw-type working body and aerodynamic cleaners.

As a result of many studies conducted both at TSNIIXprom and TITLP [3], it was determined that the main reason for the appearance of gin defects in the fiber is the constant density of the raw material in the gin chamber, therefore, after ginning the cotton raw material, the amount of defects in the fiber is large dirt, dead, fibrous seed husk and it was noted that it was much higher than the calculated standard rate due to the increase in broken seed. It is known that fiber die OVM-A-II auger-pile cleaners are installed after the fiber material condenser [4, 5].

Kuzyakova S.V. [6, 7] in his scientific work conducted theoretical and practical researches on the preparation of fiber waste for the weaving-spinning process and studied the types of fiber waste and their characteristics. In his scientific work, he recommended the use of improved ON-6-P type cleaners in order to clean dust and other impurities contained in fiber waste.

A review of literature sources in the field of cleaning technology of fiber dead or fluff from dirty impurities showed that this direction is not sufficiently developed and it is necessary to conduct in-depth theoretical and experimental research to develop an effective design of fiber dead cleaning machines that meet industrial requirements. A technical solution was developed to improve the cleaning technology of fiber products and the design of the die cleaning machine in order to increase the cleaning efficiency (Fig. 1) [8].

According to the developed technical solution, an inclined belt conveyor and an auger-plate drum cleaner that cleans the fiber die from impurities are installed here (Fig. 1). In this cleaner, the cleaned fiber die is sent through a pneumatic tube to the fiber product condenser and from there to the pressing equipment (not shown). The impurities contained in the fiber die are removed from the cleaner by means of an auger.

Figure 1. Technological process and scheme of the cleaner according to the technical solution developed to ensure efficient cleaning of the fiber die

Theoretical foundations.  It is known that uniform distribution of fluff (fiber product to be cleaned) and combing on the surface of cleaning bodies increases the intensity of cleaning fluff from small dirt, and the efficiency of separating dirty mixtures is characterized by a decrease in the level of adhesion to the material being cleaned. it is affected by the structural parameters of the machine, the level of contamination of the material being cleaned and the conditions of its delivery to the cleaning zone, more efficient distribution and the correct direction of the cleaning process with combing. Let's look at the processes in each zone when moving dead or fluffy dirty mixtures. First, we analyze the behavior of the fluff in the screw L1.

Figure 2.   Schematic diagram of the offset (fiber dead) point in the working body of the screw pile cleaner.(1- auger axis, 2- auger screw direction)

The speed of axial movement of the fiber die in the screw conveyor shell V1 is determined by the following formula (Fig. 2):

                                    (1)

Where Q - cleaner performance, t/s; D – outer diameter of screw-pile drum, m; d – diameter of screw-pile drum cover, m;  - inter-pile filling factor;- the volumetric weight of the fibrous carcass being cleaned, t/m³; С₀=0,91- fiber die shedding coefficient.

The coefficient of filling the space between the piles should not exceed the load capacity coefficient of the pile-screw cleaner:

                                                             (2)

where:  coefficient of dependence of loading capacity on the number of revolutions of the screw-pile drum; - the coefficient of dependence of the load capacity on the angle of inclination of the auger-pile cleaner, for the horizontal case .

It is desirable to determine the angle of elevation of the moving screw piles of the fiber die touching the shell due to the screw movement of the fiber die in the screw-pile drum shell at the speed V_a. The fiber die speed is the geometric sum of the axial speed V₁ and the rotational speed V_a. It is assumed that the motion of the fiber die layer is uniform and that the material obeys the laws of point motion.  In the field, the fiber die is moved by a distance L₁ during rotation of the screw-pile drum. The equilibrium equation of the fiber die can be written as follows [9], (Figure 2):

                                         (3)

where:  - the angle of elevation of the material point moving screw line; - the angle of elevation of the screw line along the outer edge;- the force of gravity on the load particle; - free fall acceleration; - the force of friction of the fiber die against the surface of the screw-pile drum; - reaction force generated on the surface of the screw-pile drum under the action of the fiber die; - the equations of the friction force generated on the inner surface of the fiber die screw-pile drum shell are written as follows:  - coefficient of friction of the load particle on the surface of the auger-pile drum;

;

.

Putting the determined ; values into expression (3), we determine the pressure force on the surface of the screw-pile drum of the fiber die. We determine the process of separation of impurities under the influence of pressure [10]:

From this expression the following can be determined:

                                  (4)

We determine the speed of fiber die around the axis of the drum on the surface of the screw-pile drum as follows.

                                                     (5)

where  represents the centrifugal force of the fiber die as a result of screw-pile drum rotation. Putting this equation (5) into the expression, we form the expression of the speed dependence of the friction force on the surface of the screw-pile drum of the fibrous die.

                                               (6)

We determine the speed of the fiber die by putting the resulting equation (6) into equation (3).

We determine the speed of the fiber die from the above expression:  

                                     (7)

Equation (7) determines the principle of separation of impurities by the speed of movement of the fiber die on the surface of the auger-pile drum. Analyzed in graphs using Maple software. 

-the friction force generated on the inner surface of the shell of the screw-pile drum cleaner when the fibrous dead mass moves, N- the reaction force of the screw surface, θ - the laws of change depending on the elevation angle f=0.03, m=0.005, m= 0.01, m=0.015 kg graph values are presented in Figures 3 and 4.

We can observe that the forces,  and  decrease with the increase of the fiber dead mass, and the elevation angle of the material point moves the screw line with the increase of the bond value.

f₂=0,03, 1-m=0,005, 2-m= 0,01,  3-m=0,015

Figure 3.  Laws of variation of the friction force generated on the inner surface of the shell of the screw-pile drum when the fibrous dead mass moves in the screw-pile drum cleaner, depending on the angle of elevation of the pile line θ

f₂=0,025, 1-m=0,005, 2-m= 0,01,  3-m=0,015

Figure 4. When the fibrous dead mass moves in a screw-pile drum cleaner, the laws of variation of the force of the reaction shown on the surface of the screw-pile drum N - depending on the length of the screw line R - the length of the screw-pile drum

From the graphs in Figure 4, it can be seen that there is a non-uniform and continuous movement of the fiber die leading to short-term stagnation. In practice, the diameter of the screw-pile drum is 500 mm, step 225 mm, number of revolutions 150 rev/min; taking into account that the friction coefficient between the shell of the auger-pile drum and the fiber dies is equal to 0.15, Using formula 7, it can be calculated that the speed of the fiber dead mass at the bottom of the piles of the auger-pile drum is 0.32 m/s, and the speed at its tip is 0.38 m/s. Such a difference in speed results in a different density of the fibrous dead mass transported in the auger-pile drum cleaner and, as a result, increases the probability of jamming.

Conclusion. As a result of research, it was found that if we assume that each gin produces an average of 900 kg/hour of fiber in an enterprise with 3 7DP-90 gins with 90 saws, 2700 kg of fiber can be produced with 3 gins in one hour. If we assume that the amount of fiber waste separated from fiber cleaners is at least 0.6% compared to cotton, this amount (assuming an average fiber yield of 34%) was found to be 47.64 kg/h. Taking into account these quantities, a technical solution was developed to improve the construction of the dead body cleaning machine in order to improve the cleaning efficiency. When the fibrous dead mass in the screw-pile drum cleaner moves, - the friction force generated on the inner surface of the shell of the screw-pile drum, N- the force of the reaction of the screw surface, θ - the laws of its change depending on the elevation angle f=0.03, m=0.005, m=0, 01, graphs of m=0.015 kg values were generated

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