Education of the republic of uzbekistan tashkent state technical university named after islam karimov

Mechanical Engineering
249 
equipment.
It is known that post-harvest processing of the crop is the most resource-intensive 
process in the entire technological chain of grain production, the implementation of which 
consumes 35.6% of fuel, 23.7% of metal and 8.9% of labor costs of all costs. Post-harvest 
processing of grain and seeds of leguminous crops takes an important place in ensuring the 
safety of the crop and bringing it to marketable condition, as well as in the preparation of high-
quality seed material [1]. 
The first stage of post-harvest processing is mechanized cleaning of a combine heap of 
grain and leguminous crops. Mechanized grain cleaning is carried out according to two main 
technologies: in-line and periodic (using separate machines or complexes, completed taking into 
account technological standards). Periodic cleaning technology is applied using self-propelled 
machines. In-line processing of food grain and seeds of leguminous crops is carried out on grain 
cleaning units and grain drying complexes, including stationary grain cleaning machines and 
lifting and transport equipment. 
To carry out post-harvest processing of grain at the present time in the farms of the 
republic, the structure of the fleet of grain cleaning machines should be (of the total number): 
preliminary cleaning machines - 45%, primary cleaning - 25%, secondary - 15%, universal - 
15%. For an individual farm, the fleet of grain cleaning equipment is determined by the gross 
harvest. 
In grain cleaning machines, various working bodies are used, the work of which is 
based on the use of a certain sign of the divisibility of the grain mass. Signs of the divisibility of 
the grain mass: dimensions (length, thickness, width); aerodynamic properties (hovering speed); 
shape and condition of the surface (frictional properties); density (gravitational properties); 
color, elasticity, magnetic properties, etc. Principles and methods of separation of grain and 
impurities, the most widely used in practice: in width - on sieves with round holes; by thickness - 
on sieves with oblong holes; along the length - on a cellular surface; in shape - on sieves with 
shaped holes (for example, triangular) or on an inclined smooth surface; by aerodynamic 
properties - in pneumatic separation channels
; 
according to the shape and condition of the 
surface - on a fleecy inclined plane; by elasticity and coefficient of shock friction - vibro-shock 
separation; by magnetic properties - magnetic separation; by density and coefficient of friction - 
vibration displacement; by density - in the case of self-sorting on conical surfaces with their 
circular translational vibrations; by size, coefficient of friction, density - on fixed inclined sieves 
[2]. 
There is a wide variety of grain cleaning machines, in the working bodies of which one 
or several principles of grain separation are implemented. For example: sieve separators (on 
sieves), air-sieve separators (sieves and pneumatic separation in channels); triers (on a cellular 
surface); aspiration columns, air separators (according to aerodynamic properties); vibro-
pneumatic stone separating machines, sorting tables (vibration movement in the aerated layer 
without sieving); stone separating machines (oscillating conical surfaces); sorting slides (on 
fixed inclined sieves); magnetic separators (by magnetic susceptibility), etc. 
. 
One of the main criteria for the quality of grain and seeds is the absence of impurities 
in it, which can pose a danger to human health, as well as affect the germination and safety of the 
product. Since the harvested grain and seeds always contain various impurities, cleaning is an 
important step for their subsequent use in the food industry and agriculture.

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