RU2811135C1 - Disc mill grinding set - Google Patents

Abstract

FIELD: pulp and paper industry.

SUBSTANCE: disk mill sets used in the pulp and paper industry for grinding fibrous materials. Headset includes concentric rings fixed on the grinding surfaces of the rotor and stator disks with parallel blade protrusions evenly distributed on them in sectors, of which the protrusions of the input, output and middle rings have a horizontal grinding surface, and the intermediate protrusions between the input and middle, middle and output grinding surfaces of different heights due to the inclination of the first to the center, and the second to the periphery of the disks, while the inclined and horizontal grinding surfaces of the middle blade protrusion form a depression at the rotor and a symmetrical convexity at the stator, in this case, the cavity at the rotor and the convexity at the stator are made in the form of circular segments with a height h = 0.1⋅r _in , chord length c = 0.85⋅r _in , arc length l = 0.881⋅r _in , radius of curvature r = 0.953⋅r _in , central angle radius of the disc entrance circle into the annular grinding zone of the headset - r _in = 0.414⋅R, where R is the radius of the circle of the trailing edge of the disks.

EFFECT: ensuring the efficiency of high quality grinding, a wide range and diversity of the nature of the trajectory of the fibrous material through the working knife cavity at different concentrations of the fibrous suspension and the natural properties of the fiber; absence of accumulations of dehydrated mass in the interblade grinding cavity, free passage of the mass through the interblade grinding cavity.

1 cl, 4 dwg

Description

The invention relates to disk mill sets and can be used in the pulp and paper industry for grinding fibrous materials.

A set for grinding equipment is known, including a disk made of several concentric rings, with knives mounted on them, connected to each other by means of fastenings that form partitions between the knives (SU No. 477208, IPC D21D 1/30, declared 08.21.1973. , BI No. 26, published July 15, 1975).

The disadvantages of the headset are:

− the complexity of the multi-variant design of the pattern of its grinding blade surface;

− not disassembled, which does not allow solving new problems without significant labor costs.

A known set of grinding machines includes rows of concentric rings with knife protrusions made in the form of prisms mounted on the rotor and stator disks (SU No. 632787, MPK D21D 1/30, declared 01/26/1977, bulletin No. 42, published 11/15/1978 .).

The disadvantages of the headset are:

− the need to change the geometry of the pattern of its working surface;

− significant labor costs for dismantling obsolete concentric rings;

− production of rings with a new design of protrusions;

− installation of new rings on the disk.

The closest known device in technical essence is the grinding set of a disk mill, which includes concentric rings fixed on the grinding surfaces of the rotor and stator disks with parallel knife protrusions evenly distributed on them in sectors, of which at the protrusions of the input, output and middle rings - horizontal grinding surface, and at the intermediate protrusions, between the input and middle, middle and output, the grinding surfaces are of different heights due to the inclination of the first - to the center, and the second - to the periphery of the disks, while the inclined and horizontal grinding surfaces of the middle knife protrusion form a depression at the rotor and a symmetrical convexity at the stator, made in the form of trapezoids (RU No. 2314380 C1, IPC D21D 1/30, B02C 7/12 declared 06/19/2006, bulletin No. 1, published 01/10/2008).

The disadvantage of the headset is that:

- the grinding and transportation surfaces of the intermediate and middle knife protrusions intersect along straight lines;

− there is a danger of a sharp jump in friction forces and resistance to the movement of the ground fibrous material accumulated on these straight lines;

− accumulation and clogging of the interknife cavity with dehydrated fibrous material is possible;

− the permeability of thick fibrous material through the interblade cavity, productivity and quality of grinding are reduced.

The invention solves the problem of ensuring the free passage of dehydrated fibrous material through the interknife cavity.

The technical result consists in ensuring the efficiency of high quality grinding, a wide range and diversity of the nature of the trajectory of the fibrous material through the working knife cavity at different concentrations of the fibrous suspension and the natural properties of the fiber; absence of accumulations of dehydrated mass in the interblade grinding cavity, free passage of the mass through the interblade grinding cavity.

The specified technical result is achieved by the fact that in the grinding set of a disk mill, which includes concentric rings fixed on the grinding surfaces of the rotor and stator disks with parallel knife protrusions evenly distributed on them in sectors, of which at the protrusions of the input, output and middle rings - horizontal grinding surface, and at the intermediate protrusions, between the input and middle, middle and output, the grinding surfaces are of different heights due to the inclination of the first - to the center, and the second - to the periphery of the disks, while the inclined and horizontal grinding surfaces of the middle knife protrusion form a depression at the rotor and a symmetrical convexity at the stator, according to the invention, the cavity at the rotor and the convexity at the stator are made in the form circular segments , with height h = 0.1 ∙ r _input , chord length c = 0.85 ∙ r _input , arc length l = 0.881 ∙ r _input , radius of curvature r = 0.953 ∙ r _input , central angle, the radius of the circumference of the entrance of the stator disk into the annular grinding zone of the headset − r _input = 0.414 ∙ R, Where R − radius of the circle of the trailing edge of the disk.

Unlike known solutions, the advantages of the proposed solution are that the overall grinding and transportation surface of the circular segments of the intermediate and middle knife protrusions of the rotor and stator is continuous, due to which there is no:

− a sharp increase in friction forces and resistance to movement of the dehydrated fibrous material being ground;

− accumulations and clogging of dehydrated fibrous material.

In fig. Figure 1 shows a frontal projection of the knife surface of the grinding disk of the headset, which includes concentric rings 1 , 2 , 3 , 4 , 5 s fixed on it, with parallel knife protrusions evenly distributed on them in sectors.

The knife protrusions of the input - 1 , output - 2 and middle - 3 rings have horizontal grinding surfaces, and the knife protrusions have 4 and 5 rings located between the input 1 and middle - 3 , middle - 3 and output - 2 rings, grinding surfaces (shaded in Figure 1 ) are inclined, respectively, to the periphery of the disks and to the center O.

In fig. Figure 2 shows a transverse axial section A-A , in which the upper rotor disk is coupled through the interblade gap with the lower stator disk.

In fig. Figure 3 shows the remote element I of the rotor.

In fig. Figure 4 shows detail II stator.

The inclined grinding surfaces 4 and 5 and the horizontal grinding surface of the middle 3 knife protrusion form:

− circular depression I, near the rotor (Fig. 2 and 3);

− circular convexity II, y, of the stator symmetrically conjugate with it (Fig. 2 and 4).

Thus (seeA-A, fig. 2) circular cavity of the rotor and the stator convexity is shaped segment , with height h = 0.1 ∙ r _input , chord length c = 0.85 ∙ r _input , arc length l = 0.881 ∙ r _input , radius of curvature r = 0.953 ∙ r _input , central angle, the radius of the circumference of the entrance of the stator disk into the annular grinding zone of the headset − r _input = 0.414 ∙ R, Where R − radius of the circle of the trailing edge of the disk.

On the radial grooves of the mating sectors, the countersunk heads of the screws that secure the rings to the disk are shown (Fig. 1).

In fig. Figure 2 shows a cross section A-A along the axis of the radial groove, which shows the longitudinal profile of the knife protrusions of the rotor and stator disks, which are interconnected through the interblade gap, which are given a rectangular shape of different heights in the cross section.

The total working area of the rings 1, 2, 3, 4, 5 is divided into sectors on which the knife protrusions are evenly distributed, forming straight parallel knives with a constant width and the same angle of inclination to one of the sides of the sector.

The lines of the working surfaces of the rotor cavity and the stator convexity formed in the cross section along the knives, conjugated through the interknife gap, are circular, successively and smoothly passing through the mating points of the rings 1, 2, 3, 4, 5 from the inlet circumferential edge to the outlet ( Fig. 2, 3 and 4).

The sum of the heights of each pair of mating rings 1, 2, 3, 4, 5 of the rotor and stator is constant.

The grinding set of a disk mill works as follows.

The fibrous suspension enters under pressure into the interblade working cavity through the inlet circumferential edge of the stator disk.

Under the action of centrifugal force, the knife protrusions of the rotor rings 1, 2, 3, 4, 5 capture and throw the mass into the inter-knife grooves of the stator rings 1, 2, 3, 4, 5.

In this case, the fibers are impacted by the lateral active surfaces of the stator knife protrusions.

At the same time, the velocity pressure is converted into static pressure, which promotes the movement of the fibrous suspension through the interblade working cavity.

Unlike known solutions, in the proposed grinding set the common surfaces of grinding and transporting the circular segments of the intermediate and middle knife protrusions of the rings 3, 4, 5, rotor and stator are continuous, due to which there is no:

− a sharp increase in friction forces and resistance to movement of the dehydrated fibrous material being ground;

− accumulations and clogging of dehydrated fibrous material.

Depending on the concentration of the suspension and the natural properties of the fiber, in the proposed grinding set, in contrast to known solutions, the mode of movement of the mass in the working inter-knife cavity, the layout of the normal and tangential components of peripheral velocities and forces at the intersection points of the cutting edges of the knife protrusions 1, 2, 3 , 4, 5 rotor and stator, angles of their intersection, inclination to radius, etc. are set at the stage of adjusting the pattern of working surfaces to the required design.

This allows you to increase the grinding ability of this set for various types of fibrous semi-finished products.

The processed fibrous semi-finished product is sent to the next stage of the technological process.

Compared to solutions, the use of the proposed disc mill grinding set will allow:

− intensify the grinding process by providing the ability to adjust the working surface pattern to the required design, depending on the concentration of the suspension and the type of material;

- increase the efficiency and high quality of grinding by making it possible to select the required mode from a wide range of modes of the trajectories of movement of the fibrous material through the working knife cavity;

− reduce energy costs due to the fullest use of mechanical and hydrodynamic energy of influence on the fibrous semi-finished product;

− increase productivity by reducing the number of cycles of passage of a fibrous semi-finished product through the inter-knife cavity per unit of time while maintaining grinding quality.

Claims (1)

Grinding set of a disk mill, including concentric rings fixed on the grinding surfaces of the rotor and stator disks with parallel knife protrusions evenly distributed on them in sectors, of which at the protrusions of the input, output and middle rings there is a horizontal grinding surface, and at the intermediate protrusions between the inlet and middle, middle and exit, the grinding surfaces are of different heights due to the inclination of the first to the center, and the second to the periphery of the disks, while the inclined and horizontal grinding surfaces of the middle knife protrusion form a depression at the rotor and a symmetrical convexity at the stator, characterized in that the depression at the rotor and the convexity of the stator are made in the form of circular segments with a height h = 0.1 ⋅ r _in , chord length c = 0.85 ⋅ r _in , arc length l = 0.881 ⋅ r _in , radius of curvature r = 0.953 ⋅ r _in , central angle , the radius of the circle of the entrance of the disks into the annular grinding zone of the headset is r _in = 0.414 ⋅ R, where R is the radius of the circle of the output edge of the disks.