RU2411122C1 - Device for fine-crushing and mixing of plastic materials, primarily, clay - Google Patents

Abstract

FIELD: process engineering. ^ SUBSTANCE: invention relates to construction, particularly, to device intended for preparation of clay mix material. Proposed device comprises case with loading bin, screw and actuator arranged in said case. Actuator comprises knives fitted on the shaft interleaving with grids made up of perforated disks with central opening secured in the case, and appliance for axial contraction arranged at actuator outlet. Outer cylindrical surfaces of the grids accommodate mounting elements interacting with elements that served to secure grinds in the case. Device incorporates thrust for knives. Each thrust is arranged ahead of appropriate knife on the material flow side, inside central opening of grid fitted ahead of said knife, and can be locked relative to the shaft. Note here that grid fixing elements are mounted to displace along the shaft and be locked relative to it. ^ EFFECT: higher reliability and service life thanks to fixed clearances between working surfaces of interacting knives and grids. ^ 6 cl, 9 dwg

Description

FIELD OF THE INVENTION

The invention relates to the field of construction, and more specifically, to the designs of devices intended for the preparation of clay raw materials.

State of the art

Known grinding devices containing a loading hopper and a working chamber with a feeding screw and a cutting unit, made in the form of fixed lattices and rotating blade knives alternating with the rotary blade knives installed in the housing between the end of the screw (see patent for invention No. 2297281, IPC: B02C 18/30, publ. 2007.04.20 and patent for the invention No. 2176554, IPC: B02C 18/06, B02C 18/30, publ. 2001.12.10). The knives are mounted on the shaft freely and are tightened to the grids by means of a compression nut.

In the process, the knives cut the material emerging from the openings of the gratings, and act on the cut material with their front faces, pushing the mass in the direction of the subsequent grating into the subsequent processing section. In this case, the material being processed exerts counter pressure on the knives, pressing them back to the grate with which the cutting was carried out. There is increased friction of the knife on the grill, which leads to quick wear of the working elements and overheating of the device.

In small low-speed devices designed for food processing, the reaction forces on the part of the transported material are negligible. For large industrial plants with high throughput, designed primarily for processing clay raw materials, the mentioned problem is significant, because the back pressure exerted by the clay material on the knives is substantial. The result is a rapid wear of the working bodies, as well as overheating of the device, leading to its breakdown, stop.

In the solution according to patent No. 2297281, they try to solve the problem of reducing back pressure and mass recirculation by making knives of different axial size and shape. However, this greatly complicates the manufacture of the device, increases its cost. The implementation of knives with a hub abutting against adjacent gratings and providing some clearance between the knife and adjacent gratings also does not solve the problem, because there is a rapid abrasion of the hub of a rotating knife on a fixed lattice.

As the closest analogue to the claimed solution, a device for grinding and mixing plastic materials, mainly clay (see patent No. 2297324, IPC: B28C 1/14, publ. 04/20/2007), containing a housing with a loading hopper, sequentially mounted in the case there is a screw and an actuator, including knives mounted on the shaft, alternating with grids in the form of perforated disks with a central hole, and an axial preload means installed at the output of the actuator. On the outer cylindrical surface of each lattice, mounting elements are made that interact with the corresponding lattice fixing elements in the housing.

A disadvantage of the known device, as well as the above, is the low reliability, it is subject to increased wear of the working elements and frequent overheating due to the large backpressure forces on the material side and the absence of a fixed gap between the knives and gratings.

Disclosure of invention

The task of the invention is to increase the reliability and durability of the device by creating fixed gaps between the working surfaces of the interacting knives and gratings.

The problem is solved by the claimed device for grinding and mixing plastic materials, mainly clay, comprising a housing with a loading hopper, a screw and an actuator sequentially mounted in the housing, and knives mounted on the shaft, alternating with grids in the form of perforated disks with a central hole, made with installation elements on the outer cylindrical surface, interacting with the elements of fixation of the gratings in the housing, and the means of axial preload tained at the output of the actuator.

New in the device is that it is equipped with stops for knives, each of which is mounted on the shaft in front of the corresponding knife from the side of the material flow, inside the central hole of the grill installed in front of this knife and with the possibility of fixing its position on the shaft, while the fixing elements of the grids in they are mounted with the possibility of movement along the shaft and with the possibility of fixing their position.

A positive technical result of the proposed solution is the ability to create a fixed gap between the working surfaces of the interacting working elements: knife and grill, as well as the ability to control the size of the said gap.

Rotating elements of the actuator (knives and stops) do not come into contact with stationary working elements - gratings, which helps prevent overheating of the mechanism, extend the service life of working elements and increase the reliability of the entire device. It should be noted the compactness of the device, the manufacturability of its manufacture, simplicity and ease of use.

The stops are mounted on the shaft so that the end surface of the stop contacts the end surface of the corresponding knife, which follows from the interpretation of the stop as a part restricting the movement of another part, and fix the stop relative to the shaft. The possibility of fixation is provided by the design of the stop and the axial preload means.

In this case, the gratings have some mobility along the shaft on which the knives with stops are mounted, provided by the mechanism for securing the gratings in the housing. By moving the lattice fixing elements along the shaft, the position of the lattice is changed, setting the necessary clearance. The gap is set between the knife and the grill located in front of it, because It is in the direction of the previous, from the side of the material flow, lattice that the total forces acting on the knife during the operation of the device are directed. In this case, a stop placed inside the central hole of the grate holds the knife in a certain position and does not impede the movement of the grate. To set a given gap value, simple devices such as probe templates can be used.

During the operation of the device, clay material pressed through the holes of the grate is cut off from its surface by a knife, which, due to a certain inclination of the frontal face, pushes the clay being cut from this grate to the side that follows. In this case, the material acts on the knife in the opposite direction, pressing it back to the grate with which the cutting occurs. The emphasis fixed on the shaft holds the knife, preventing it from pressing against the surface of the grill. The gap established between the working surfaces of the knife and the grill is maintained.

Depending on the specific operating conditions, the gap between the working elements can be adjusted, which provides wide technological possibilities for using the device.

For reliable fastening of the lattice in the housing, it is preferable to have two fastening elements placed diametrically opposite to the lattice. The lattice fastening elements located on one side are mounted on the same axis parallel to the knife shaft, with the possibility of moving along it. And elements located on the other side are on the other axis.

The mentioned axis can be made in the form of a threaded rod pivotally fixed at one end in the housing, while the fastening elements of the gratings are performed with open grooves in which the said axis is laid, which ensures the convenience and speed of assembly of the device. The position of the fixing elements relative to the axis is fixed by means of nuts.

The installation elements of the grating can be made in the form of protrusions, grooves or radial holes, as in the example below, on its cylindrical surface. The lattice fastening elements are performed with reciprocal elements interacting with certain mounting lattice elements.

The emphasis can be made in the form of an annular element with rods that provide the ability to fix the emphasis on the shaft in a certain position, as, for example, in the decision on application No. 2008143571 of November 6, 2008.

However, the simplest and most technological implementation of the emphasis is its implementation in the form of a sleeve mounted on a shaft between two adjacent knives, the so-called spacer sleeve. The assembled mechanism is pressed by means of axial preload, thus fixing the position of the knives and stops relative to the shaft. The sleeve has a length exceeding the thickness of the grate in the hole of which it is located. The sleeve length determines the maximum possible movement of the grill along the shaft. The size of the sleeve form the volume of the cutting sections.

It is advisable to make the bushings composite, for example in the form of a set of rings of different thicknesses, which will allow, by reducing the wear sleeve as the working surfaces of the cutting elements wear, to extend the life of knives and grids.

Brief Description of the Drawings

The invention is illustrated by the accompanying drawings, in which:

figure 1 shows a General view of the device in front;

figure 2 is a section aa in figure 1;

figure 3 shows the mechanism for fixing the grids in the housing, isometry;

figure 4 - fixing mechanism of the grids, top view;

figure 5 is the same, view a in figure 4;

figure 6 is the same, view In figure 4;

figure 7 shows the element of fixing the lattice in the housing;

on Fig - axis of the mechanism for securing the lattices in 2 types;

figure 9 - fragment I in figure 2, shows the gap between the grill and the knife,

The implementation of the invention

A device for grinding and mixing plastic materials contains (see Fig. 1) a housing 1 with a loading hopper 2 and a working chamber 3, in which a screw 4 and an actuator are connected in series with the rotation drive. The actuator includes (see figure 2) mounted on the shaft 5 blade knives 6 with stops 7, alternating with the knives transverse lattices 8 in the form of perforated disks with a Central hole for the shaft and means of axial compression 9.

The diameter D of the central hole of the gratings 8 is larger than the diameter d of the shaft 5. In the space formed as a result of the mentioned diameter difference between the shaft and the inner annular surface of the grating 8, a stop 7 is placed.

In the drawings, an example embodiment of the device stops 7 are made in the form of bushings formed from several rings of different thicknesses. However, this design of the stop is preferred and does not limit the possibility of using stops of another design, including in the form of just a sleeve.

The shaft 5 can be made in the form of a continuation of the end part of the auger shaft or in the form of a separate shaft connected to the auger shaft and having one rotation drive with it.

The mechanism for securing the gratings in the casing contains (see Figs. 3-8) fastening elements 10 made with open slots 11 and fingers 12 interacting with radial holes 13 made on the outer cylindrical surface of the gratings 8. Each grating in the casing is secured by two elements 10 located diametrically opposed to the lattice.

Located on one side of the gratings, the elements 10 are mounted on a common axis 14, pivotally mounted in the housing 1, and fixed by means of nuts 15.

The device is assembled as follows.

The working bodies are installed on the shaft 5 with the open cover of the working chamber 3, while the first set the turns of the screw 4 and the stone-cutting pair 16 (if any), and then alternately string the stop 7, the grill 8 and the corresponding knife 6. onto the shaft. installation of all working bodies, the cutting knife is mounted last. The knives are mounted on a shaft with an angular offset to prevent mutual overlap of the blades. A threaded nut 9 is screwed onto the shaft shank 5, which is threaded, while the knives 6 and the bushings-stops 7 located between them are moved close to each other, pressed against one another by the ends.

The grids 8 are fixed, for which the fingers 12 of the elements 10 are inserted into the radial holes 13 of the grids. In the grooves 11 of the elements 10, the axis 14 is laid. The gap between the knives and gratings is adjusted, for which the corresponding templates are installed between the latter. The thickness of such patterns is equal to the size of the required clearance. By sliding the elements 10 along the axis 14 by means of the fixing nuts 15, the desired clearance is set. The position of the nuts 15 can be additionally fixed with locknuts (not shown in the drawing).

The size of the gap is selected from the limits of 0.5-2.5 mm. The optimum clearance is determined empirically during operation for a particular raw material and production conditions. A larger gap allows to reduce the load on the engine and the overall heating of the installation, however, if the gap is too large, part of the material being cut remains on the grate, the knife slides along it. As a result of friction, the mentioned material dries up, the quality of the crushed material (clay) deteriorates, and productivity decreases. If the gap is too small, then the knife is strongly pressed to the surface of the grate, there is an increased abrasion of the working surfaces, their wear increases, and durability decreases. The recommended optimum clearance is 1.5 mm.

The device operates as follows.

The source material, in particular clay, is poured into the hopper. Once in the working area of the screw 4, the clay is partially crushed, mixed and moved by the screw into the working area of the cutting unit. Clay is pressed to the first lattice 8 and pressed through its holes, falling into the zone of action of the knife 6 (see Fig. 9). The end cutting edges of the knife 6 cut off the pressed material from the lattice 8 and reject it towards the subsequent lattice 8 'due to the inclination of the frontal edge. In this case, the material exerts counter pressure on the knife 6, directed to the surface of the lattice 8, with which he carried out the cutting. The sleeve 7 abuts with its end against the end wall of the knife 6, not allowing the latter to press against the surface of the grating 8. Thus, between the working surface of the knife 6 and the corresponding surface of the grating 8, interacting with each other, a guaranteed (fixed) gap S ₁ is maintained, which ensures optimal operating conditions of the device. As a result, overheating of the device and rapid wear of the working bodies are prevented, frequent breakdowns and device stops are eliminated, and productivity is increased.

On the other side of the knife, i.e. between it and the subsequent lattice, the gap S _{2 is} maintained due to the fact that the forces acting on the knife are directed towards the previous lattice.

Over time, as the knives and grates wear out (wear), the gap increases, so you need to periodically check and adjust the position of the working elements of the device.

In the process of adjustment, the thrust sleeve can be replaced with a new one, or, if it is composite, reduced by removing one or more of its constituent rings.

Claims (6)

1. Device for grinding and mixing plastic materials, mainly clay, comprising a housing with a loading hopper, a screw sequentially mounted in the housing and an actuator including knives mounted on the shaft, alternating with grids in the form of perforated disks with a central hole, made with mounting elements on an external cylindrical surface interacting with the fastening elements of the gratings in the housing, and an axial preload means installed at the outlet o the mechanism, characterized in that the device is equipped with stops for knives, each of which is mounted on the shaft in front of the corresponding knife from the side of the material flow, inside the central hole of the grill installed in front of this knife with the possibility of fixing its position relative to the shaft, while the fastening elements of the grids in the case mounted with the possibility of movement along the shaft and with the possibility of fixing their position relative to it. 2. The device according to claim 1, characterized in that it contains for each lattice two fastening elements placed diametrically opposite to it, and the elements located on one side of the lattices are mounted on a common axis parallel to the shaft. 3. The device according to claim 2, characterized in that the axis is made in the form of a threaded rod pivotally fixed at one end in the housing, while the lattice fastening elements are made with open grooves to accommodate the said axis and fixed relative to it by nuts. 4. The device according to claim 1, characterized in that the mounting elements of the grids are made in the form of radial holes, while the fastening elements of the grids in the housing are made with fingers interacting with the said holes of the grids. 5. The device according to claim 1, characterized in that the emphasis is made in the form of a sleeve with a length exceeding the thickness of the lattice in the hole of which it is installed. 6. The device according to claim 5, characterized in that the sleeve is made integral.

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