RU2623761C2 - Centrifugal-pneumatic separator of grain material - Google Patents

Abstract

FIELD: agriculture.

SUBSTANCE: centrifugal-pneumatic separator of grain material contains an annular pneumatic separating channel with a lower branch pipe for airflow inlet and cleaned grain material outlet, a loading inlet branch pipe for the grain material to be cleaned, an outlet branch pipe for exhaust air with light impurities, a rotational conical spreader equipped with an adjusting damper for feeding the grain material into the pneumatic separating channel and equipped with several cones fixed to the common shaft at some distance from each other and having on the bottom, with the exception of the lower one, a central opening. The upper cone has the largest diameter of the cone and the opening, and the subsequent cones in the direction from top to bottom have gradually decreasing diameters. The annular pneumatic separating channel consists of the upper, middle (main) and lower parts. The main part is formed by coaxially located the outer and the inner cones, which are diffusers (in the direction from top to bottom). Their larger base is placed below at approximately the same height. The angle between the generatrices in the longitudinal diametrical cross-section of the outer cone is less than the analogous angle of the inner cone. The height of the outer cone is larger than the height of the inner one.

EFFECT: improving the cleaning quality and reducing grain losses.

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Description

The invention relates to a device for cleaning grain material and can be used in agricultural production, in the milling and elevator and animal feed industries.

Known centrifugal-pneumatic separator, consisting of a loading nozzle, an annular pneumatic separating channel, a rotary conical spreader mounted on a shaft, a nozzle for introducing air into the pneumatic separating channel and the withdrawal of purified grain material from it, a loading nozzle and a nozzle for exhaust air with light particles [ one].

When the separator is operated with a rotary conical spreader rotating around a vertical axis, a fan-shaped annular jet of the processed grain material is introduced into the annular pneumatic separating channel, which is affected by the upward air flow, which results in the separation of the material into two fractions - light impurities and the purified product.

According to the design and technological process, the same centrifugal-pneumatic separator has an air-sieve machine MZP-50 for primary cleaning of grain material [2].

The drawback of these centrifugal-pneumatic separators is the low effect of cleaning the grain material with an annular pneumatic separating channel due to the uneven concentration of the grain material (grain density) in the cleaning zone: it is greatest in the area adjacent to the spreader, and as it approaches the outer wall of the channel, it decreases and the smallest value is near this wall. This causes uneven resistance to the movement of the air flow in the radial and, therefore, in the annular directions of the channel, and the air flow velocity in these directions is also uneven: its smallest value is at the spreader, and the greatest is at the outer wall of the channel. For this reason, in the channel zone adjacent to the spreader, there is no effective separation of light impurities from the processed grain material, as a result of which its cleaning effect is reduced. In addition, with the marked distribution of the grain material and the air flow rate in the channel, full grain is removed to the waste fraction (with light impurities) from the zone adjacent to the outer wall of the channel.

Along with the marked machine separator MZP-50, the following drawback is still inherent. Since the air flow into the separator is introduced through openings made on the upper part of its body - at the level of the spreader, and is discharged by means of a pipe located also in the upper part of the body and connected to the sedimentation chamber, with this design of the air system, the air flow affects the grain being processed the material is practically only in the zone of its exit from the loading window (pipe) and, as a matter of fact, does not affect the fan-shaped annular stream of material coming down from the spreader. In addition, when placing the pipe that exhausts the exhaust air stream in the radial direction, the uniformity of the air velocity field is distorted, as a result of which an axisymmetric “working” air stream is not achieved, which also reduces the effect of cleaning the grain material from light impurities and grain losses (removal from light impurities).

Also known is a centrifugal-pneumatic separator for cleaning grain material [3], which consists of an annular pneumo-separating channel, the working part of which is coated with two concentric circular cylinders. At the bottom of the channel there is a pipe that introduces air into the channel and removes cleaned grain material from it, and an upper pipe with an adjustment flap that takes out the exhaust air stream with light impurities from the channel, and a pipe for introducing material into the air separator.

The processed grain material is introduced into the channel by a rotary conical spreader having a number of cones fixed at a certain distance from each other on a common drive shaft. When placing, for example, three cones, the upper cone has the largest diameter, and the diameter of subsequent cones gradually decreases. A central hole is made at the bottom of the upper and middle cones, while the diameter of the hole in the first of them is larger than the diameter of the second.

The process of the separator proceeds as follows. From the loading nozzle, the grain material to be cleaned is fed to a rotating upper cone. From it, part of the material under the action of centrifugal force is introduced into the zone adjacent to the outer wall of the channel, in which it is exposed to an upward flow of air entering the channel through the lower pipe. Another part of the grain material through the hole of the upper cone is fed to the second cone, from which part of the material enters the middle zone of the channel, in which it is exposed to air flow. The rest of the material from the second cone through its hole is directed to the rotating lower cone, from which it is fed into the area adjacent to the inner wall of the channel, and also falls under the influence of air flow. Light impurities are emitted from the grain material in the pneumatic separation channel from the grain material, which are removed from the separator through the upper nozzle, and the grain material purified from air-separated impurities is removed from the channel through the lower nozzle.

According to the technical nature and the set of essential features, a centrifugal-pneumatic separator for cleaning grain material is closest to the claimed pneumatic separator, and it is adopted as a prototype [3].

The disadvantage of this separator is the low cleaning effect of the grain material, which is caused by the fact that the air separation channel has an annular shape formed by the lateral surfaces of two coaxially placed circular cylinders, and the parabolic trajectories of the particles of grain material introduced into the channel by the upper cone, reaching the surface of the outer cylinder, are layered on it is practically not exposed to the ascending air flow. This nature of the movement of the material particles relative to the outer wall of the channel is explained by the fact that the speed of the particles introduced laterally at an angle to the vertical ascending air flow tends to a certain limit, which is called the critical velocity, in magnitude and direction [2]. In this case, the direction of the limiting velocity is vertical, and it is achieved with a sufficiently large particle displacement, i.e. with a large length (height) of the channel, as a result of which the dimensions and mass of the separator increase significantly.

The second disadvantage inherent in the pneumatic separator prototype is due to the fact that particles of material introduced into the channel by the lower cone also move along parabolic trajectories. Moreover, between the inner wall of the channel and the extreme (located near the wall) parabolas, the space is not occupied by moving particles. This “dead” zone of the channel increases due to the influence of the vertical air flow, which gives the particles a lateral force impulse directed to the outer wall of the channel (all particles, including those reaching the surface of the outer wall of the channel, undergo such a pulse).

The problem that needs to be solved is to achieve the active effect of the air flow on the separated grain material in the entire volume of the working part of the air separation channel, i.e. in increasing the cleaning effect and reducing grain losses.

The problem is solved using the proposed centrifugal-pneumatic separator of grain material, the annular pneumatic separating channel of which consists of upper, middle (main) and lower parts, the main part being made of coaxially located truncated outer and inner cones, which are diffusers (in the direction from top to bottom) while their larger base is located below at approximately the same height, the angle between the generators in the longitudinal diametrical section of the outer cone is less than this angle at inner cone, and the height of the outer is greater than the height of the inner

A diagram of a centrifugal-pneumatic separator of grain material is shown in the drawing.

The centrifugal-pneumatic separator of grain material consists of an annular air-separating channel, consisting of upper 1, middle (main) 2 and lower 3 parts. The main part is formed by coaxially located truncated outer 4 and inner 5 cones, which are diffusers (in the direction from top to bottom), with their larger base placed at the same bottom below at approximately the same height, while the angle between the generators in the longitudinal diametrical section of the outer cone is smaller than the similar angle of the inner cone, and the height of the outer cone is greater than that of the inner.

In the upper part, coaxial to the channel, there is a pipe 6 for loading grain material and a pipe 7, which exhaust air flows with light impurities from the channel; it is equipped with an adjustment flap 8. In the lower part of the channel 3, a pipe 9 is installed coaxially with it, intended for introducing air into the channel and withdrawing purified grain material from it. The rotary conical spreader introducing the grain material into the pneumatic separation channel is a series of cones fixed at some distance from each other on a common shaft 10. The diagram shows three cones - the upper 11, middle 12 and lower 13. The upper cone has the largest diameter, and the diameter of subsequent cones gradually decreases. At the bottom of the upper 11 and middle 12 cones, respectively, the Central holes 14 and 15 are made, while the diameter of the hole 14 is larger than the diameter of the hole 15.

The technological process of a centrifugal-pneumatic separator proceeds as follows. The grain material to be cleaned from the loading nozzle 6 is fed to the upper rotating cone 11, by which a part of the material is introduced under the action of centrifugal force into the annular pneumatic separation channel, in which it is exposed to the upward air flow entering the channel through the lower nozzle 9. The rest of the grain material through the hole 14 of the cone 11 is introduced into the rotating cone 12, from which part of the material is discharged into the pneumatic separation channel, in which the air flow acts on it. The remaining part of the material from the cone 12 through the hole 15 enters the rotating lower cone 13, from which it enters the air separation channel and also falls under the influence of the air stream.

In the pneumatic separating channel, light impurities are released by the air flow, which are discharged from the pneumatic separator through the upper nozzle 7. Subsequently, this aerosol mixture, consisting of air and light impurities, enters, for example, a centralized air system for air purification before discharge into the atmosphere (in the diagram, the system shown). Grain material, purified from air-separable impurities, is discharged from the pneumatic separation channel through the lower pipe 9.

Improving the quality and reducing grain losses along with the introduction of the grain material into the cleaning zone in three streams - the upper, middle and lower cones, respectively, into the zone adjacent to the outer wall of the channel, to its middle part and to the inner wall, is achieved due to the above mentioned design of the main part air separation channel. So, with the length and inclination of the surface of the outer cone relative to the vertical direction, the parabolic trajectories of the particles of the grain material introduced into the pneumatic separating channel are not layered on the inner wall of its main part, but are exposed to an upward air flow in the loosened form. As a result, a more complete release of light impurities is achieved in this area of the air separation channel.

With a marked inclination of the surface of the inner cone relative to the vertical direction, the extreme parabolic trajectories (located closer to the surface) of the particles of grain material introduced into the channel by the lower cone of the spreader move along this surface, thereby eliminating the "dead" space in the area of the inner wall of the channel, i.e. . vortex flow of air mixtures (air and light impurities), and the working space of the air separation channel is used more efficiently.

Depending on the physicomechanical properties of the separated impurities and the purpose of the processed material (seed, commercial grain), the speed of the air flow in the channel is regulated by turning the damper.

Thus, during the operation of the proposed centrifugal-pneumatic separator, a positive effect is achieved consisting in increasing the purity of the processed grain material and reducing the loss of full grain.

Literature

1. Goncharov B.C., Grabelkovsky N.I. Centrifugal-pneumatic separator for grain materials // Tractors and agricultural machinery. - 1968. - No. 6. - S. 26-28.

2. Sychugov NP, Sychugov Yu.V., Isupov V.I. Mechanization of post-harvest processing of grain and grass seeds. - Kirov; FGUIPP "Vyatka", 2003. - 368 p.

3. Patent 2266165 (Russian Federation). Centrifugal-pneumatic separator for cleaning grain material. / N.P. Sychugov. - Application of 02.03.2004, publ. in BI No. 35, 2005. - prototype.

Claims (1)

A centrifugal-pneumatic separator of grain material containing an annular pneumatic separating channel with a lower nozzle for introducing air flow and output of cleaned grain material, a loading nozzle for introducing cleaned grain material, an outlet nozzle for exhaust air with light impurities, a conical rotary spreader equipped with an adjustment flap for feeding grain material into a pneumatic separating channel and equipped with several cones fixed on a common shaft on some apart from each other and having at the bottom, with the exception of the bottom, a central hole, the upper cone has the largest diameter of the cone and the hole, and for subsequent cones, from top to bottom, these diameters gradually decrease, characterized in that the annular air separation channel consists of an upper, middle ( main) and lower parts, and the main part is formed by coaxially located outer and inner cones, which are diffusers (in the direction from top to bottom), with their larger base placed at the bottom of approximately at the same height, thus forming an angle between a longitudinal diametric section of the outer cone angle less than that of the inner cone and the height greater than the height of the outer internal.

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