RU2533910C2 - Disc mill for grain grinding - Google Patents

Abstract

FIELD: agriculture.

SUBSTANCE: mill comprises a hopper, a housing with loading and unloading openings. Inside the housing the drive and passive discs are eccentrically mounted. The drive disc is cantilever fitted on the drive shaft and is provided with a central opening for loading of the ground material into the inter disc space. The passive disc located on the shaft fixed to the housing is mounted with the ability to rotate freely and change the eccentricity relative to the drive disc. The grinding surface of each disc consists of an inner (12), medium (13) and outer (14) belts with riffles. The grinding discs are equipped with radial channels (15) of constant diameter of different length parallel to diametrical disc axes with access to the grinding surface of the middle belt of the discs. The channels have windows (16) with the width equal to the diameter of the channel. The lateral sides of the channels and sides of the channels closest to the centre of the disc are formed perpendicular to the diametrical disc axes. The side (18) of the channel furthest from the centre of the discs is made at an angle to the bottom of the channel. Between the middle and outer belts of the discs the ring grooves are made of triangular cross section (19).

EFFECT: improving conditions of transfer of the ground product from the middle belts to the outer belts of the discs leads to more complete filling them and improves the performance of the mill.

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Description

The invention relates to a device for grinding grain and can be used in farms, at the enterprises of food and feed industry.

Known disk mill for grinding grain crops (patent of the Russian Federation No. 2424056 C1, IPC B02C 7/10 from 07.20.2011). The mill includes a driving and passive discs mounted eccentrically relative to each other, the grinding surface of which consists of an inner, middle and outer belts with riffles. The middle and outer zones are made in one plane parallel to the diametrical axes of the disk, and the inner zone is in the plane at an angle γ to them. The grinding surface of the disks is equipped with channels of constant diameter not less than the size of the grain of the crushed crops. The channels are made of different lengths parallel to the diametrical axes of the disks. At the beginning, the channels have access to the surface of the inner zones with the formation of grooves with the largest width at the beginning of the groove equal to the diameter of the channel d and a length of 1 equal to

$$l=\begin{array}{l}\mathrm{<figure-callout\; id="2"\; label="d"\; filenames="00000008.png"\; state="\{\{state\}\}">d</figure-callout>}\\ 2\end{array}/\sin \gamma ,(\mathrm{one})$$

where d is the diameter of the channel;

γ is the angle of inclination of the grooves of the inner belt to the diametrical axes of the grooves, smaller than the width of the inner belt.

At the end of the channels there are windows with access to the grinding surface of the middle belt of disks with a width equal to the diameter of the channel, the sides of which are the sides that are closest to the center of the disks and are made perpendicular to the diametrical axes of the disks. The side farthest from the center of the disk is made at an angle β to the bottom of the channel, determined from the expression

$$tg\beta =\frac{r\cdot {\omega }^2-g\cdot f}{r\cdot f\cdot {\omega }^2+g},(2)$$

where r is the current value of the radius, m;

ω is the angular velocity of rotation of the disk, rad / s;

f is the coefficient of sliding friction;

g - acceleration of gravity, m / s ² .

The total length of the windows on the grinding surface of the leading and passive discs in the radial direction is equal to two widths of the middle zone.

The disadvantage of this design is a slight decrease in productivity due to an increase in the large fraction of the product at the boundary of the middle and outer zones, since the product entering through the channels of different lengths into the middle zone contains, along with previously poorly ground grains, whole grains, which makes it difficult to transfer whole grains and coarse particles from the interdisk space with middle belts to the interdisk space with external belts having small values of pitch and depth of the grooves.

The technical result from the use of the invention is an increase in productivity due to the emerging possibility of improving the conditions for the transition of the crushed product from the middle belts to the outer belts, leading to a more complete filling of them.

The technical result is achieved in that in a disk mill for grinding grain, including a hopper, a housing with loading and unloading openings, inside which a drive disk is mounted eccentrically relative to each other, cantileverly mounted on the drive shaft and provided with a central hole for loading the crushed material into the interdisk space, and placed on a shaft mounted on the housing, a passive disk mounted with the possibility of free rotation and change of eccentricity relative to the leading suit, the grinding surface of each disk consists of an inner, middle and outer belts with flutes, the grinding disks are equipped with radial channels of constant diameter, of different lengths parallel to the diametrical axes of the disk, with access to the grinding surface of the middle belt of the disks, with a width equal to the diameter of the channel, side and nearest to the center of the disk, the sides of which are perpendicular to the diametrical axes of the disks, and the side farthest from the center of the disks is made at an angle β to the bottom of the channel, and a ring is made between the middle and outer belt of the disks high grooves of a triangular section with a width H, determined from the expression

, $$H=\frac{h}{tg\beta }$$

,

and depth h, uniformly decreasing from the middle belt to the outer belt from a value of (2.5 ... 3) h ₂ to 0,

where h is the depth of the annular groove, m;

h ₂ - the height of the grooves of the middle belt, m

In the grooves of the chosen shape, a large product, firstly, accumulates, and secondly, freely leaves them and enters the zone of the outer belts at the moment of finding the ring grooves in the zone of the outer belts during rotation of the leading and passive disks due to their eccentric arrangement. Thus, the annular grooves forcibly transfer the product to the zone of the outer zones.

The fine fraction obtained during the passage of the inner and middle disk belts and whose dimensions are commensurate with the pitch and height of the corrugations of the external belt, constantly leaves the ring grooves and enters the interdisk space of the external belts. All this increases the amount of product entering the zone of the outer zones, which leads to an increase in the performance of the disk mill.

The proposed device is illustrated by drawings: figure 1 shows a diagram of a disk mill for grinding grain crops; figure 2 shows the leading disk; figure 3 shows a passive disk; figure 4 shows a section A-A of figure 2; figure 5 shows the model of the disk.

The disk mill (Fig. 1) includes a hopper 1 mounted on a housing 2 having a loading hole 3 and an unloading hole 4. Inside the housing 2 there are two grinding discs, one of which is the drive disc 5, which is cantilevered on the drive shaft 6 has a Central hole 7 for loading the crushed product (grain) into the interdisk space, the second passive disk 8 is installed with the possibility of free rotation. The disk 8 is mounted eccentrically relative to the disk 5. The disk 8 can be moved in the longitudinal direction before work due to the spring mechanism 10, which allows you to pre-adjust the gap between the grinding disks 5 and 8 depending on the required quality of the product. The disk 8 is mounted with the possibility of changing the eccentricity relative to the disk 5 before starting work using the mechanism 11. The grinding surface of each of the disks (figure 2 and figure 3) consists of an inner belt 12, middle 13 and outer 14, provided with corrugations in the form of concentric circles having different pitch and depth. Master and passive drives of FIG. 2 and FIG. 3 are provided with radially arranged channels 15 having different lengths. Channels 15 having the same length are made symmetrically relative to each other, which does not require disk balancing. All channels have windows 16 (FIG. 2 and FIG. 3) equal in diameter to the channel, the sides of which are nearest to the center and are made perpendicular to the diametrical axes of the disks, and the side 18 farthest from the center of the disks is made at an angle β to the channel bottom.

The total length of the windows 16 in the radial direction of the leading 5 and passive 8 disks is equal to two widths of the middle belt 13. On the length of the inner belt, the channels have access to the surface with the formation of grooves 17, the largest width of which is at the beginning of the channel and equal to its diameter, while the channel does not extends beyond the inner belt 12 of the master and passive drives. Between the middle belt 13 and the outer 14 of the driving 5 and passive 8 disks, an annular groove 19 (Fig. 4) is made in the form of a right triangle, one of the legs of which is equal to the width H of the annular groove, and the second length h = (2.5 ... 3) h ₂ , where h ₂ - the height of the grooves of the middle belt, is equal to the maximum depth of the groove. With this value of h, the depth of the groove will be commensurate with the size of the grain. The hypotenuse of this right-angled triangle, which is the bottom of the groove, is inclined to the diameter of the disk at an angle β equal to the angle of inclination of the side 18 of the channel 15 farthest from the center of the disk to the bottom of the channel (the diameter of the disk) and is determined from expression 2. The width of the groove H is from the rectangular triangle ABC (figure 4):

, откуда $$H=\frac{h}{tg\beta }$$

from where

, $$H=\frac{\left(2.5...3\right)\cdot h_2\cdot \left(r\cdot f\cdot {\omega }_2+g\right)}{r\cdot {\omega }^2-f\cdot g}$$

,

where h ₂ - the height of the grooves of the middle belt, m;

r is the current value of the radius, m;

f is the coefficient of sliding friction;

ω is the angular velocity of rotation of the disk, rad / s;

g - gravity acceleration, m / s ² , and depth h, uniformly decreasing from the middle belt to the outer belt from a value of (2.5 ... 3) h ₀ to 0.

Disk mill operates as follows. The grain from the hopper 1 through the loading hole 3 enters the grinding yard, where it is captured by the corrugations of the inner belt 12 of the leading and passive discs and carried away in rotational motion. During the interaction of the grooves of the inner belts 12, the product is preliminarily crushed, then part of it under the action of centrifugal forces, as well as the pressure created by the newly incoming product, moves in the interdisk space of the inner 12 and middle 13 belts, and part through channels 15 immediately enters the middle 13 zone the belts through the windows 16. The product passing the middle belts 13 enters the annular grooves 19, where it accumulates. A large fraction leaves them at the moment of coincidence of the annular grooves of the leading 5 and passive 8 disks with the grinding zone of the outer belts 14 due to the eccentric arrangement of the disks. The fine fraction, the sizes of which are comparable with the pitch and depth of the corrugations of the outer belt, continuously leaves the grooves 19 and enters the grinding zone of the outer zones. All this contributes, in comparison with the prototype, to improve the filling of the interdisk space in the zone of the outer belts and, as a result of this, to increase the productivity of the disk mill. The crushed product is removed through the discharge opening 4.

Claims (1)

A disk mill for grinding grain, including a hopper, a housing with loading and unloading openings, inside which a drive disk is mounted eccentrically relative to each other, cantileverly mounted on the drive shaft and provided with a central hole for loading the crushed material into the interdisk space, and placed on the shaft mounted on case, a passive disk mounted with the possibility of free rotation and eccentricity relative to the leading disk, the grinding surface of each disk comp ith from the inner, middle and outer belts with riffles, the grinding disks are equipped with radial channels of constant diameter of different lengths parallel to the diametrical axes of the disk, with access to the grinding surface of the middle belt of disks with a width equal to the diameter of the channel, the sides and sides of which are perpendicular to the center of the disk the diametrical axes of the disks, and the side farthest from the center of the disks is made at an angle β to the bottom of the channel, characterized in that the annular grooves of a triangular cross section are made between the middle and outer belt Nia width H, defined by the expression $$\text{H}=\frac{\text{h}}{\text{tgβ}}$$

, and depth h, uniformly decreasing from the middle belt to the outer belt from a value of (2.5-3) h ₂ to 0, where h is the depth of the annular groove, h ₂ is the height of the grooves of the middle belt.

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