RU2732941C1 - Grain-cleaning screw conveyor - Google Patents

Abstract

FIELD: agriculture.

SUBSTANCE: disclosed invention relates to devices for cleaning grain from undesirable impurities, and in particular to screw conveyors, cleaning grain during movement of grain in screw, and can be used in agriculture, flour-grinding and elevator industry, feedstuff industry and other industries. Grain cleaning screw conveyor comprises a frame, an inclined screw conveyor with a cylindrical casing, mounted on the frame with the possibility of changing the angle of inclination, arc-like sieve, located in the lower and middle part of the casing between the loading and unloading ends, drive of screw conveyor, exhaust fan, receiving hopper for initial grain and unloading branch pipe for cleaned grain. Arched sieve is made string and is fixed to casing on elastic pads. Sieve strings are arranged along casing generatrix. On the upper parts of the casing on the side of the loading end, above the sieve and on the side of the unloading end, perforated sections are selected, which are equipped with arc-like, perforated sheets interfaced with the outer surface of the casing and capable of tangential movement. Under the sieve air intake hood connected via cyclone by means of hoses with fan is installed with casing. Receiver for small impurities is arranged under discharge opening of cyclone. An air-permeable bag for receiving light impurities is installed to the outlet nozzle of the fan. Neighboring sieve strings are made with different elasticity. Conveyor is configured to change rotation frequency. Cleaned grain discharge pipe is equipped with elastic hose.

EFFECT: high efficiency of separating fine and light impurities, as well as high quality of cleaning grain.

4 cl, 3 dwg

Description

The invention relates to a device for cleaning grain from unwanted impurities and, in particular, to auger conveyors that cleanse grain in the process of moving grain in a screw, and can be used in agriculture, flour and elevator industry, feed industry and other sectors of the national economy.

Known grain cleaning auger conveyor (see US No. 3727759, class A01F 12/46; B07B 1/18; B07B 1/20; B65G 33/00; B07B 001/06, publ. 17.04.1973), including an inclined screw conveyor, in the lower part of which there is a stationary arcuate sieve, a receiver for impurities that have passed through the sieve, a receiving hopper for initial grain and an unloading hole for cleaned grain. In the process of moving the grain in the auger, it falls on an arc-shaped sieve, on which, under the action of gravitational forces, small particles are sieved and enter the receiver, and the cleaned grain moves up the conveyor to the destination.

The main disadvantages of the known conveyor are:

- low efficiency of the separation of impurities on the sieve, since the released impurities move along cyclic trajectories together with the flow of the main grain (are carried away by it) and do not reach the surface of the sieve, this is due to the fact that the gravitational forces acting on small particles are comparable with the forces of viscous friction of stratified grain in the auger;

- in the process of operation, the sieve becomes clogged, its free cross-section decreases, and, consequently, the completeness of the separation of small impurities decreases.

The closest to the claimed device of a grain-cleaning auger conveyor in terms of the function and technical solution is a grain-cleaning auger conveyor (see US No. 4684458, class B07B 1/26; B07B 1/18; B07B 9/00; B07B 009/00, publ. 04.08 .1987), including a frame with an inclined cylindrical casing installed on it with an auger concentrically located in it, an arcuate sieve located between the loading and unloading end of the casing in its lower part, auger drive, an exhaust fan, a receiving hopper for initial grain and an unloading branch pipe of cleaned grain ...

The main disadvantages of the known device are:

- low efficiency of separating small impurities on the arcuate sieve, since only the lower part is its active working area, and the holes of the side parts of the sieve are clogged with passing particles, since the gravitational forces acting on the particles are directed vertically downward;

- the connection of the suction branch pipe of the fan with the over-grain space in the casing of the screw conveyor makes it difficult for particles to pass through the sieve, since air seeps through it into the cavity of the casing, i.e. an aerodynamic force is formed, acting in the opposite direction of movement of passing particles through the sieve, in addition, this factor contributes to the clogging of the sieve;

- low efficiency of separation of light impurities, since air intake from the auger casing occurs in a limited area commensurate with the suction pipe of the fan, while only dust-like particles located above the grain layer directly in the air intake zone are exposed to the air flow;

- grain crushing takes place, since the perimeter of the screw screw pinches the grains between the sharp edges of the sieve holes.

- dust is formed in the working area of the grain cleaning auger conveyor, as small impurities, when leaving the sieve, contain a large amount of dust.

The problem to be solved by the claimed solution is to increase the efficiency of separating small and light impurities in the screw conveyor when the transported grain is in it.

The technical effect obtained when solving the problem is expressed in improving the quality of grain cleaning, mainly by reducing the number of intermediate grain cleaning operations and reducing the content of undesirable impurities in it.

To solve the supplied grain auger conveyor, including a frame, an inclined screw conveyor with a cylindrical casing mounted on the frame with the possibility of changing the angle of inclination, an arcuate sieve located in the lower and middle parts of the casing between the loading and unloading ends, a screw conveyor drive, an exhaust fan, a receiving the bunker for the original grain and the unloading branch pipe for refined grain, characterized in that the arched sieve is made of string and fixed to the casing on elastic cushions, while the sieve strings are located along the generatrix of the casing, and on the upper parts of the casing from the side of the loading end, above the sieve and from the side of the unloading end, perforated sections are selected, equipped with arcuate perforated sheets conjugated with the outer surface of the casing, made with the possibility of tangential movement, in addition, an air intake umbrella is installed under the sieve hermetically with the casing, connected through a cyclone along means of hoses with a fan, while a receiver for small impurities is located under the discharge neck of the cyclone, and an air-permeable bag is installed to the fan outlet for receiving light impurities. In addition, adjacent sieve strings are made with different elasticity. In addition, it is configured to change the rotational speed of the screw conveyor. In addition, the unloading branch pipe for cleaned grain is equipped with an elastic sleeve.

Comparative analysis of the features of a new solution with the features of analogs indicates the compliance of the declared solution with the “novelty” criterion.

The essence of the proposed device is that the arcuate sieve is made of a string, with strings located along the generatrix of the casing and located in the middle part of the casing, and an air intake umbrella is installed hermetically with the casing under the string sieve, the outlet of which is connected by means of a polyethylene reinforced sleeve to the inlet side pipe of the cyclone, and the upper outlet of the cyclone is connected through a polyethylene reinforced sleeve with the inlet of the fan, a receiver of small impurities is located under the discharge neck of the cyclone, and an air-permeable bag for receiving light impurities is installed under the outlet of the fan.

The features of the distinctive part of the claims provide a solution to the claimed technical problem.

The upper parts of the casing from the side of the loading end, above the string sieve and from the side of the unloading end are made perforated and closed (provided) with arcuate perforated sheets conjugated with the outer surface of the casing, having the possibility of tangential movement, and the unloading branch pipe of the casing is connected to an elastic sleeve.

The arcuate string sieve is fixed in the lower and upper part of the casing by means of elastic cushions, and the adjacent sieve strings are made with different elasticity.

The screw drive is configured to change the rotational speed of the screw rod.

The execution of the arcuate sieve with a string, with strings located along the generatrix of the cylindrical casing, provides, in comparison with other perforated surfaces, a significant increase in the efficiency of separating small impurities, which is explained by the nature of the interaction of the grain layer moved by the screw surface. In the process of moving grain by the auger in the casing, the screw surface of the conveyor together with the grain layer have their own cyclic vibrations in the radial direction of the casing. Moreover, in the middle part of the casing, these vibrations are greater than from the side of the loading or unloading end, due to the presence of a sieve of the declared design. Under the influence of these vibrations, the string sieve vibrates slightly, thereby increasing the efficiency of screening through particles and reducing blockage by particles stuck in perforations. Placing strings along the generatrix of the cylindrical casing increases the frequency and amplitude of vibration of the strings. The main grain of non-passable size, moving along the strings "washes them", thereby reducing the number of particles stuck between the strings. In addition, when using a string sieve located along the generatrix of the casing, the damage to the kernels during movement in the auger is reduced.

Installation of an air intake hood under a string sieve, connected through a sleeve to a cyclone and a suction fan, makes it possible to increase the efficiency of separating small and light impurities, since in this case aerodynamic forces act on particles, in addition to gravitational forces, intensifying the passage of impurities through the sieve. In the cyclone, small and light impurities are distributed into separate fractions, which also increases the separation efficiency.

Execution of the upper parts of the casing from the side of the loading end, above the string sieve and from the side of the unloading end with perforated and closed arcuate, perforated sheets conjugated with the outer surface of the casing, having the possibility of tangential movement, allows you to optimize the aerodynamic field over the grain layer moving inside the casing. The displacement of the perforated sheets provides a uniform intake of light impurities from the side of the loading and unloading ends of the casing, as well as laminar movement of light impurities in the area of the string sieve. At the same time, the installation of an elastic sleeve on the unloading nozzle allows to exclude air leaks into the inner cavity of the casing, which facilitates obtaining a uniform velocity field above the grain layer, and, consequently, reducing turbulent air flows from the loading end.

Fastening the arcuate string sieve to the casing on elastic cushions increases the amplitude-frequency characteristics of the string sieve, which leads to an increase in the efficiency of sifting through impurities. The execution of adjacent strings of the sieve with different elasticity also increases the amplitude-frequency characteristics of the sieve when it interacts with the vibrating grain layer and reduces clogging of the gaps between the strings. When pressing the grain layer on a sieve with alternating elastic strings, less elastic strings bend more than less elastic ones, as a result of which clogging of interstring gaps decreases and the quality of sieving increases.

When separating grain materials with different physical and mechanical properties, as well as with different content of small and light impurities, the variable frequency of the screw drive allows you to optimize the rotational speed of the screw conveyor, at which the maximum possible release of impurities is achieved.

The claimed technical solution is illustrated by the drawing, where figure 1 shows a diagram of a grain cleaning auger conveyor (side view) with sections along the lines A-A (a) and B-B (b), figure 2 is a longitudinal section of a casing with a screw conveyor with a view of the string sieve (air intake umbrella is not shown) and a section of the device along the line C-C, figure 3 is a general view of a stringed arched sieve.

The grain cleaning auger conveyor contains an inclined cylindrical casing 1 with a receiving hopper 2, in the upper part of the casing 1 from the side of the loading end, above the string sieve and from the side of the unloading end, perforated sections are arranged with the possibility of tangential movement, closed by arcuate perforated sheets 3 conjugated with the outer surface of the casing , 4, 5 (the drive of sheets is not shown in the drawing) (see Fig. 1). In this case, the casing 1 is installed on the frame 9 with the possibility of changing the angle of inclination.

On the side of the unloading end, there is a drive 6 of the auger 26 and an unloading branch pipe 7 of refined grain, which can be additionally equipped with an elastic sleeve 8 (see Fig. 1, 2). The drive 6 can be configured to change the rotational speed of the auger 26. Between the loading and unloading ends of the casing 1 on the lower side in the middle there is a string sieve 27, moreover, the adjacent strings in the sieve 27 can be made with different elasticity, under which it is hermetically sealed with the casing 1 an air intake umbrella 10 is installed with an outlet pipe 11 connected by means of a polyethylene reinforced sleeve 12 to an inlet pipe 13 of a cyclone 14. In this case, cyclone 14 is connected to a fan 18 through a polyethylene reinforced sleeve 16, an outlet pipe 15 of cyclone 14 and an inlet pipe 17 of a fan 18. To the outlet a removable air-permeable bag 20 for receiving light impurities is installed on the branch pipe 19 of the fan 18. Under the discharge opening 21 of the cyclone 14 is a receiver 22 for small impurities.

Under the arcuate perforated sheets 3, 5, the surface of the casing 1 is perforated 23, 24. Under the arcuate perforated sheet 4 above the string sieve 27, the casing surface is also perforated 25 (see Figs. 2a, 2b and 3).

Inside the casing 1, a screw 26 is concentrically mounted. The ends of the string sieve 27 are fixed by a shell 28. From the side of the loading end of the casing 1, the sieve 27 is fixed by means of an elastic cushion 29, a clamp 30 and a bolt connection 31, and the unloading end - by means of an elastic cushion 32, a clamp 33 and a bolt compound 34 (see Fig. 2, 3).

The grain cleaning auger conveyor works as follows. The original grain material enters the receiving hopper 2, from where, under the action of the auger 26, driven in rotary motion from the drive 6, moves along the inner cavity of the casing 1. In the process of moving, small impurities due to gravitational and aerodynamic forces developing due to the fan 18 are sieved through the grains into the lower part of the layer and, passing through the string sieve 27, fall into the air intake umbrella 10.

When the grain layer moves under the perforated section 24, light particles on the surface of the layer are carried away by the air flow and in the area of the air intake umbrella 10 also pass into the lower grain layer and fall on the string sieve 27.

When the grain moves under the perforated section 23 from the upper layers, the remaining light parts under the action of the air flow are again directed towards the air intake umbrella 10.

The air flow passing through the perforated section 25 entrains light impurities into the lower grain layer located on the string sieve 27, and also contributes to the entry into the air intake umbrella 10, from which small and light impurities under the action of the air flow from the fan 18 through the sleeve 12 enter the cyclone 14, in which they are divided into fractions: small heavy impurities enter the receiver 22, and light, mainly dust-like impurities enter the air-permeable receiving bag 20.

During the operation of the grain cleaning auger conveyor, the selection of the optimal air flow in the casing 1 to achieve the maximum release of small and light impurities is carried out by changing the volume of the open section of the perforated sections 23, 24 and 25 by moving the perforated arcuate sheets 3, 4 and 5 along the casing 1.

When separating grain materials with different physical and mechanical properties, as well as with different contents of small and light impurities, optimization is also performed by changing the rotational speed of the screw 26.

The use of the inventive device for a grain cleaning auger conveyor increases the efficiency of separating small and light impurities in the process of moving grain in the auger, which makes it possible to reduce the number of intermediate grain cleaning operations, to improve the quality of grain material by reducing the content of undesirable impurities in it.

Claims (4)

1. Grain cleaning auger conveyor, including a frame, an inclined screw conveyor with a cylindrical casing mounted on the frame with the possibility of changing the angle of inclination, an arcuate sieve located in the lower and middle part of the casing between the loading and unloading ends, a screw conveyor drive, an exhaust fan, a receiving hopper for initial grain and an unloading branch pipe for refined grain, characterized in that the arcuate sieve is made with a string and fixed to the casing on elastic cushions, while the sieve strings are located along the generatrix of the casing, and on the upper parts of the casing from the loading end, above the sieve and from the side of the discharge end, perforated sections are selected, equipped with arcuate perforated sheets conjugated with the outer surface of the casing, made with the possibility of tangential movement, in addition, an air intake umbrella is installed under the sieve hermetically with the casing, connected through a cyclone by means of hoses with a fan, while under the discharge neck of the cyclone there is a receiver for small impurities, and an air-permeable bag for receiving light impurities is installed at the fan outlet. 2. Grain cleaning auger conveyor according to claim 1, characterized in that adjacent sieve strings are made with different elasticity. 3. Grain cleaning auger conveyor according to PP. 1 and 2, characterized in that it is configured to change the rotational speed of the screw conveyor. 4. Grain cleaning auger conveyor according to PP. 1, 2 and 3, characterized in that the unloading branch pipe for cleaned grain is provided with an elastic sleeve.

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