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7
Section 7. Technical sciences
Daliyev Shuxrat Latibjonovich, research associate - the competitor, Andijan machine-building Institute Republic of Uzbekistan Djurayev Anvar Djurayevich, doctor of technical sciences, professor, Tashkent Institute of textile and light industry, Republic of Uzbekistan E-mail: elmonovsirojiddin@gmail.com
DEVELOPMENT OF THE DESIGN AND JUSTIFICATION OF THE PARAMETERS OF THE COMPOSITE FLAIL DRUM OF A COTTON CLEANER
Abstract: The article presents a constructive scheme and principle of operation of the drum spinner with elastic elements of the cotton cleaner from small litter. The results of full-factor experiments of the recommended design of the spinner are presented. The equation of the output factor-purification effect is obtained and graphical dependences of the influence of the output parameters are constructed: the rotational speed of the drum, the distance between the tips of the pins and the mesh, and the rigidity of the rubber bushing. On the basis of the analysis of the graphs, the optimum values of the parameters of the pin drum with elastic elements are determined.
Keywords: Drum, elastic element, cleansing effect, cotton, speed, hardness, rubber.
In the well-known design of the cotton ginning unit, cotton purities isolated in the fine-cleaning section with large coarse grains
cleaning sections from small and large litter are combined [1]. Under the brush drums there are two serrated drums and under them the grids forming a grid for cleaning raw cotton from large weed impurities. In the fine cleaning section, the pin drums and mesh surfaces below them are successively installed.
The main disadvantage of this design is the low effect of cleaning cotton from weeds especially from small litter. The total removal of isolated weed impurities resulting in the mixing of small weed im-
and volatiles in the large-scale cleaning section. This leads to additional difficulties in the regeneration and re-cleaning of cotton. In addition, in the existing design of the cotton cleaner from fine sora, the cleaning effect is not high. Due to the inadequate vibrations of the spear drum due to its greater mass (moment of inertia), as well as the inhibition of cotton in the transition zones between the spear drums due to the insufficient angular velocity of the subsequent spear drum.
Figurel. Scheme of the spinner with an elastic element
The proposed construction is explained by a drawing, where (Figure 1.) shows the general scheme of the cleaning section of a cotton ginning unit [2]. The cleaning section of the ginning unit contains, in the horizontal plane, a drum 2 in the form of sections consisting of a cylinder 4 with pins 5 and laths 6 mounted on the shaft 1 by means of flanges 3 and rubber annular sleeves 7. In this case, the cylinder 4 is made of sectional including three circumferential pins 5 and six-rowed rows. A dripping grid is installed under the drums 8. In the process of the cleaning machine operation, the clogged raw cotton transported in the ginning unit goes to the drum 2, the pins 5 and the straps 6 of which capture the cotton flys and drag them through the mesh surface 8. The separated fine weed is dropped through the openings of the mesh surface 8 and then out of the cleaning zone through the pneumatic siphon. Carrying the drum 2 sections of three circular rows of pins 5 and slats 6 allows a reduction in the mass (moment of inertia) of each section, there is the possibility of circular oscillations of sections during the interaction of the pins 5 and the strips 6 with the cotton flys. This leads to intense isolated weed impurities from the cotton loaves.
To determine the amplitude of the angular oscillations of the outer cylinder, a section consisting of sections with pins 5 and bars 6 carried out theoretical studies. The drum 2 was considered as a two-mass system for each section. In this case, the system of differential equations describing the dynamics of a system in the steady state has the form [3]
J< = My sinat-c(j-j2)-b(j-<j>2)
J2<2 = b (<j-j)-c (j-<2)-Mc where, J1, J2 - Moments of inertia of the inner cylinder and the section of the spinneret; - Angular movements of the inner cylinder and section; c, b - Stiffness and dissipation coefficients of an elastic element; My -Amplitude ofperturbation in steady state; Mc - Resistance from dragged cotton.
To determine the steady-state oscillation of the system, we seek solution (1) in the following form
Aq>2 ,10_1 pad
1,25 1,0
0,75 0,5 0,25
(2)
(1)
2,5
5,0
7,5
10,0
12,5
15,u
= A sinot + B cosot
= C sinot + D cosot To determine arbitrary constants A, B, C, D, we obtain the corresponding equations. In the final form, we have expressions for determining the oscillation amplitudes of the inner cylinder and the corresponding section with the drum pins
fa =>/A2 + B2; 02 =VC2 + D2; (3)
where
A = M [(c - hw2 )( + bW) - J2b2W ]; B = ^-bW k k
C = M[(c - Jy )bV - J2bW ]; D = M J2ba>2 (c - J2a2)
k =
c - J,a2
ba
0
-ba
- ba c - Ja ba 0
0
- ba
- J2a2 ba
ba 0 ba
-J2a2
The numerical solution of the problem was carried out with the following values ofthe parameters: My = 1,5 2,0 Nm; a = 45 50 c-1; c = 400 ^ 600 Nm/rad; b = 7,2 ^ 10 Nm/rad. At the same time, graphical dependencies of the change A02 from variation Mc J2 and c, which are presented on figure 2. Analysis of the results shows that with increasing values of the rigidity of the elastic element, the amplitude of the oscillations ^ and 02 decrease.
It can be seen from the graphs obtained that with increasing technological resistance from raw cotton, pulled by the wheel barrel, nonlinear regularity increases the swing angle of the drum section headset. Thus, when c = 400 Nm / rad and increase Mc from 2,5 Nm till 12,5 Nm swing A02 decreases from 0,01 rad till 0,054 rad, and when c = 800 Hm / pad angular displacement A02 is within (0,24 -1,03)• 10-1 pad . To select the necessary amplitude of the angular vibrations of the headset, it is expedient to select the values of the moment of inertia J2. According to the analysis of the graphs in figure 2b.
A<p2 ,10 pad
1,8
1,0
0,6
15,0
20,0
J, JO" K21 f
a) b)
Figure 2. A - dependence of the change in the amplitude of the angular movements of the headset from the technological loading where, 1 - c=800 Nm/rad; 2 - c=600 Nm/rad; 3 - c=400 Nm/rad; B -regularities in the variation in the swing of the oscillation of the headset from the change in its moment of inertia and the stiffness coefficient of the elastic element where, 1 - c=800 Nm/rad; 2 - c=600 Nm/rad; 3 - c=400 Nm/rad
It can be noted that the increase of J2 from 0,042 kgm 2 to 0,17 kgm 2 swing A02 decreases from 0,16 rad down to 0,059 rad when c = 400 Nm / rad, and at a value of the rigidity of an elastic rubber bush 600 Nm/rad A02 decreases from 0.127 rad to 0.052 radians. To ensure the swing of the angular vibrations of the drum headset within (0,08-0,11) rad recommendable values it is been
J2 = (0,068 -0,12) kgm2, c = (550-650) Nm/ rad. Taking into account the recommended design parameters of the pin drum, a prototype design was designed and manufactured. During the experiments rubber bushings were made of various three brands of rubber, the characteristics of which are presented in table 1.
Figure 3. Dependences of the change in the cleaning effect on the variation of the drum speed (a), the distance from the end of the picks to the grid (b), and the coefficient of circular rigidity of the rubber bushing (c)
Table 1.
№ Brand of rubber Relative extension at break,% Shore hardness Coefficient of stiffness, Nm/rad
1 3826 MBC 327% 60 0.20-10 4
2 1338 360% 72.5 0.30-10 4
3 3825 MBCS 287% 85 0.40-10 4
To optimize the main parameters of the recommended drum spinner, a full-factor experiment was conducted. For the input factors were adopted: X1- rotational speed of the pin drum, min-1; X2-distance between the ends of the pins and the net surface, mm; X3-circular stiffness of the rubber bush, Nm/rad. For the outgoing factor was to take the purifying effect of raw cotton. The investigations are given according to the procedure [4]. The resulting regression equation has the following form:
Y = 38,81 +1,81x1 -1,71x2 +1,08x3 -
-0,63xx2 - 0,2x2 - 0, 2x22 - 0,21xJ ; The equation of the emerging factor is obtained in the following form:
M =-4,04 + 1,84n + 2,03f + 0,225v -
z ' ; (5)
-4-10-3n-t-8-10-5 •n2 -0,022t2 -10-3v2 The numerical solution of the obtained equation (5) was carried out on a computer using the Excel program and graphical dependencies were constructed (see figure 3). In Figure 3 of 3a shows the graphical dependences of the effect on the cleaning effect of the rotational speed of the drum. Analysis of the graphs shows that, with an increase in the drum rotation speed from 380 min-1 to 480 min-1, the effect of cotton cleaning changes according to a nonlinear regularity. The maximum cleaning effect is obtained when (435-445) min-1. It should be noted that the greatest cleaning effect was obtained at X2=20 mm and X3=0,30-10 4 Nm/rad (see crooked 2, figure 3) Accordingly, at X2=17 mm and X3=0,20-10 4 Nm/rad correspond to the 1-crooked a X2=23 mm and X3=0,40-10 4 Nm/rad correspond to the 3-crooked. According to the 2-crooked curve in Figure 3a the effect of cotton cleaning reaches up to 39.6%. With an increased drum rotation speed of more than 445 min-1, the reduction in the cleaning effect is explained by the fact that the cotton in the drag zone passes very quickly
and does not have enough time to loosen sufficiently, and at the same time the litter is reduced, and at rotational speeds.
The drum is lower than 335 min-1, the strength of the interaction of the pins with the volatiles becomes insufficient, as well as the volatility with the cleaner grid, which does not allow the required isolated litter. In Figure 3 b the driving curves of the change in the cleansing effect of cotton from the variation of the distance between the ends of the pins and the mesh. The first graph corresponds to the minimum values of X1 and X3, the second to the middle and third to the high values of X1 u X3. Analysis of the graphs in Figure 3b shows that the greatest purifying effect of raw cotton from small litter 39.8% was obtained with the distance between the ends of the pins and the grid (18-19) mm at X1 = 430 min-1 and X3 = 0,30-10 4 Nm/rad. In Figure 3c are graphs of the change in the cleaning effect of the increase cotton from the movement of the circular stiffness of the elastic sleeve of the pin drum.
The best cleaning effect in shallow litter 38,3% was obtained at average values X1 = 430 min-1, X2 = 20 mm within the following limits of the change in the circular stiffness of the rubber drum sleeve (0,30-0,35)404 Nm/rad [5].
Conclusions. An effective design of a composite spear drum with a rubber bushing of a cotton cleaner from small litter has been developed. On the basis of theoretical studies, the laws of angular displacement of the headset and the shaft of the drum are determined, the calculated values of the parameters of the drum are justified. P The results of full-factor experiments recommended optimal values of outgoing factors: the drum rotation frequency is 444 min-1; The distance between the ends of the pins and the net is 19 mm; The circular stiffness of the rubber bush is - 0,35-10 4 Nm/rad, which provides the effect of cleaning cotton from small litter to 39.8%.
References:
1. Zikriyev E. and other. Primary processing of raw cotton. Textbook, Tashkent. Mehnat, - 1999. - P. 390-397 p.
2. Djurayev A., Daliyev Sh. Cleaning section of the cotton ginning unit. Patent Res. Uzb. №. FAP 2016 0007, - 2016.
3. Djurayev A., Mavlyanov A., Kholturayev H., Daliyev Sh. Perfection of designs and methods for calculating the parameters of pin drums of cotton cleaners from small litter. Monograph. - Germany, Lambert Academic Publishing, - 2016. - P. 41-53 p.
4. Daliyev Sh. L., Djurayev A.Dj., Nosirov N.Zh. Optimization of the parameters of the pin drum on the elastic elements of the small litter cleaner. Republican scientific conference "Actual problems of innovative technologies in the context of integration of science, education and production. Textiles - 2017". Tashkent, - 2017.
5. Spiridonov A. A. Planning an experiment in the study of technological processes - Moscow: - Mechanical Engineering - 1981. - P. 70-84 p.
