RU2274491C1 - Breaking set of a disc mill - Google Patents

Abstract

FIELD: the invention refers to breaking sets of disc mills.

SUBSTANCE: the breaking set includes discs gathered together of sectors whose working surface consists of a central and periphery ring zones with grooves between knives overlapped on the periphery with dams located on eccentric bows relatively to the centers of the discs with forked knives some of which are shortened, limited with the peripheral ring zone. They are alternated with whole knives passing through the both zones. At that the knives and the radiuses of the dams are directed from the center to the periphery of the disc under an angle to its radius and a number of knives on a unit of length of an arbitrary circumference of the ring zones increases in radial direction to the largest neighboring edge of the disc, the grooves between knives expand from lateral surfaces of the dams - from the side of the central ring zone in the direction towards the center of the disc, and from the side of the peripheral zone in direction to its largest neighboring edge. At that the radial extension of the central and the peripheral ring zones are fulfilled with correlation defined out of given expression.

EFFECT: increases quality of milling, effectiveness , time of cutting edges of knives, life and reduces energy consumption.

2 dwg

Description

The invention relates to grinding sets of disk mills and is intended for use in the pulp and paper industry, but may find application in other industries, in particular in the chemical and construction industries.

Known grinding headset disk mill, comprising two disks consisting of a Central and peripheral grinding rings, and the peripheral grinding ring of each disk is made of abrasive ceramics [1].

The disadvantage of this headset is the high energy consumption during its use.

Known grinding headset disk mill, including two assembled from sectors of the disk, the working surface of which consists of a Central ring with knives and a peripheral ring with protrusions directed from the center to the periphery, located at an angle to the radius of the disk, the number of which per unit circumference of the peripheral ring increases in radial direction to its periphery [2].

A disadvantage of the known headset is the inability to provide the optimal ratio of the number of loading cycles, the degree and time of development of the fibrous material in the working areas of the Central and peripheral grinding rings at a given specific energy consumption.

Closest to the claimed is a grinding headset of a disk mill, including two assembled from disk sectors, the working surface of which consists of a central and peripheral annular zones with inter-knife grooves, overlapped on the periphery by jumpers located on arcs eccentric relative to the center of the disks and with forked knives, of which shortened, limited by a peripheral annular zone, alternate with solid ones passing through both zones, while the knives and the radii of the jumpers are directed from the center to the peri disk periphery at an angle to its radius, and the number of knives per unit length of an arbitrary circumference of the annular zones increases in the radial direction to the largest circumferential edge of the disk [3].

A disadvantage of the known headset is:

- the inability to ensure the optimal ratio of the number of loading cycles, the degree and time of development of the fibrous material in the working areas of the Central and peripheral grinding rings at a given specific energy consumption;

- the small width of the inter-knife grooves at the entrance from the central annular zone to the peripheral one, which leads to the appearance of large resistances when penetrating into the peripheral inter-knife cavity and with further advancement of the fibrous semi-finished product in it;

- the small width of the inter-knife grooves at the exit from the peripheral annular zone, which leads to the appearance of large resistances when the fibrous semi-finished product leaves its working cavity, to its inhibition in this section, to an increase in the chopping effect and, as a result, to a decrease in the quality of processing and increase energy consumption.

The invention solves the problem of optimizing the process, improving the quality of grinding and productivity while reducing energy consumption and increasing the service life of the cutting edges of knives.

The technical result consists in optimizing the grinding process, improving the quality of grinding and productivity, as well as in reducing energy consumption and in increasing the service life of the cutting edges of knives.

The optimization of the grinding process is ensured by the optimal ratio of the degree of development of the fibrous semi-finished product in the central and peripheral zones of the disks. Improving the quality of grinding is carried out by ensuring the optimal ratio of the number of loading cycles of the fibrous semi-finished product in the central and peripheral zones of the disks. The increase in productivity is due to the provision of the optimal number of cycles of passage of the fibrous prefabricated grinding zone. Reducing energy costs is achieved by ensuring the optimal ratio of the development time of the fibrous semi-finished product in the central and peripheral zones of the disks. The increase in the operating life of the cutting edges of the knives is provided due to the most proportional distribution of the flow of fibrous semi-finished product in the cavities formed by the central and peripheral annular zones of the disks.

To ensure the specified technical result in a grinding set of a disk mill, including two assembled from sectors, the disk working surface of which consists of a central and peripheral annular zones with interknife grooves overlapped on the periphery by jumpers located on arcs eccentric relative to the center of the disks and with forked knives from which are shortened, limited by a peripheral annular zone, alternate with solid ones passing through both zones, while the knives and the radii of the jumpers are directed from the center to the periphery of the disk at an angle to its radius, and the number of knives per unit length of an arbitrary circumference of the annular zones increases in the radial direction to the largest circumferential edge of the disk, according to the invention, the intercutaneous grooves expand from the side surfaces of the webs from the side of the central annular zone towards the center the disk, and from the peripheral zone in the direction of its largest circumferential edge, while the radial length of the Central and peripheral annular zones are made with the ratio predelyaemym from the expression:

a / b = b / (a + b) = 0.62,

where: a is the radial extension of the central annular zone of the disks;

b is the radial extension of the peripheral annular zone of the disks.

The ratio of the length of the Central and peripheral ring zones according to the formula a / b = b / (a + b) = 0.62, the authors determined experimentally. This ratio allows you to provide the most rational distribution:

- annular flow of fibrous semi-finished product in the Central and peripheral annular zones;

- resistance forces to the annular flow of the fibrous semi-finished product when it is moving sequentially through both grinding zones;

- tangential and high-frequency shock force impacts on the fibrous semi-finished product progressively moving through the inter-knife cavity and the inter-knife gap of both zones;

- the time spent by the fibrous semi-finished product in each of the zones.

Figure 1 shows a frontal projection of one of the sectors of the grinding headset of a disk mill (a thin line indicates the circumference of the inlet opening of the stator disk closest to the center O of the disks); figure 2 is a section aa along the longitudinal axis of the intercutaneous grooves common to the central and peripheral annular zones.

The grinding headset of a disk mill includes two assembled from disk sectors. The working surface of the disk sectors consists of a central 1 and peripheral 2 annular zones with inter-knife grooves 3 overlapped at the periphery by jumpers 4. The jumpers 4 are located on arcs eccentrically relative to the center O of the disks. 1, the radial extent of the central 1 annular zone is indicated by a, and the radial extent of the peripheral 2 annular zone is indicated by b. The length of the central radial annular zone 1 and the peripheral radial 2 annular zone are made from the ratio determined from the expression: a / b = b / (a + b) = 0.62.

The central 1 and peripheral 2 annular zones are provided with forked knives 5 and 6. Shortened knives 5 bounded by the peripheral annular zone 2 alternate with solid knives 6 passing through both annular zones 1 and 2. The radii of the jumpers 4 and knives 5 and 6 are directed from the center O to the periphery of the disks at an angle to their radius. The number of knives 5 and 6 per unit length of an arbitrary circumference of the annular zones 1 and 2 increases in the radial direction to the largest circumferential edge of the disk.

The inter-knife grooves 3 are made expanding from the lateral surfaces 7 and 8 of the jumper 4 located, respectively, from the central 1 side of the annular zone, towards the center O of the disk and from the peripheral 2 of the annular zone, towards its largest circumferential edge (Fig. 1 and FIG. 2, section AA).

The working surface of the proposed headset is further divided into two further annular parts, of which the peripheral part is located in the frontal plane (blackened in FIG. 1), and the central part (shaded in FIG. 1) is made in the form of a truncated cone with an inclined generatrix to the frontal plane under angle α equal to 2 ... 5 ° (figure 2, section aa).

Grinding headset disk mill works as follows. The fibrous semi-finished product under pressure enters through the inlet of the stator disk, and then, due to the forces of adhesion to the knifeless wall of the rotating rotor disk, overcoming the friction force with the knifeless wall of the stator disk, it is twisted and rushed under the action of centrifugal and tangential forces in the direction of entry into the central annular zone 1 of the disks (figure 1).

Getting into the cavity formed by the central annular zones 1 of the stator and rotor disks, the fibrous semi-finished product is subjected to pre-treatment in the form of an impact with a given frequency on a part of it that is in the inter-knife cavity, with dynamic, angular, contact of the intersecting central parts of the whole split knives 6 of a rotating - rotor and fixed - stator disks. At the same time, under the influence of centrifugal and tangential forces, the fibrous semi-finished product moves in the direction of the peripheral annular zone of the 2 disks, undergoing cyclic pressure drops at the points of convergence and divergence of the intersecting central parts of the whole bifurcated knives 6 of the movable and fixed disks, which increases the impact.

In the cavity formed by the peripheral annular zones of the 2 stator and rotor disks, the pre-treated fibrous semi-finished product is subjected to final processing in the form of high-frequency loading cycles on bundles of fibers that fall into the inter-knife gap, accompanied by their destruction at the inter-fiber level. This increases the uniformity and dispersion of the fibrous semi-finished product, which contributes to its promotion under the action of centrifugal and tangential forces. As it moves, in the radial direction to the output circumferential edges of the disks, the frequency of loading cycles increases due to an increase in the number of knives 5 and 6, which increases the degree of dispersion of the fibrous semi-finished product and its permeability, while reducing the static and dynamic forces of resistance to its movement from the side and bottom surfaces of the inter-knife grooves 3 and the internal cavities of the bifurcated knives 5 and 6 of the peripheral annular zone 2 of the stator and rotor disks.

This, in contrast to the known headset designs, is facilitated by the most proportional distribution of the fiber prefabricated stream in the cavities formed by the central 1 and peripheral 2 zones with radial lengths equal to a and b, respectively, which is ensured by their optimal ratio a / b = b / (a + b) = 0.62, as well as the fact that the inter-knife grooves 3 are expanded from the lateral surfaces 7 and 8 of the jumpers 4 in the direction, respectively, to the center O of the disks and in the direction to their largest circumferential the edge.

The processed fiber prefabricated goes to further processing.

The use of this invention will allow:

- to optimize the grinding process due to the optimal ratio of the degree of processing of the fibrous semi-finished product in the working cavities of the Central 1 and peripheral 2 annular zones of the disks;

- to improve the quality of grinding by ensuring the optimal ratio of the number of loading cycles of the fibrous semi-finished product in the working cavities of the Central 1 and peripheral 2 annular zones of the disks;

- increase productivity by ensuring the optimal number of cycles of passage of the fibrous prefabricated grinding zone;

- reduce energy consumption by ensuring the optimal ratio of the development time of the fibrous semi-finished product in the working cavities of the Central 1 and peripheral 2 annular zones of the disks;

- increase the operating life of the cutting edges of the knives 5 and 6 by ensuring the most proportional distribution of the flow of fibrous semi-finished product in the cavities formed by the Central 1 and peripheral 2 ring zones of the disks.

Information sources

1. SU, No. 502993, IPC D 21 D 1/30, declared on 02.01.1974, bull. No. 6, publ. 02/15/1976

2. SU, No. 730916, IPC D 21 D 1/30, declared 08.08.1978, bull. No. 16, publ. 04/30/1980

3. Equipment for pulp and paper production. Edited by V.A. Chichaev. T.1. Page 176 ... 179, Fig. 4.11. Moscow: Forestry industry. 1981

Claims (1)

Grinding headset of a disk mill, including two assembled from disk sectors, the working surface of which consists of a central and peripheral annular zones with interknife grooves overlapped on the periphery by jumpers located on arcs eccentric relative to the center of the disks and with forked knives, of which are shortened, limited by a peripheral annular zone, alternate with whole, passing through both zones, while the knives and the radii of the jumpers are directed from the center to the periphery of the disk at an angle to its radius, and the number of knives per unit length of an arbitrary circumference of the annular zones increases in the radial direction to the largest peripheral edge of the disk, characterized in that the inter-knife grooves expand from the lateral surfaces of the webs from the side of the central annular zone towards the center of the disk, and from the peripheral zone towards its the largest circumferential edge, while the radial extension of the Central and peripheral annular zones are made with the ratio determined from the expression a / b = b / (a + b) = 0.62, where a is the radial extension of the central annular zone of the disks; b is the radial extension of the peripheral annular zone of the disks.

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