UA79858C2 - Device for crushing - Google Patents

Abstract

The invention relates to the branch of machine building, to devices for crushing materials with rotary cutters, and it can be used for crushing of metal chips, polymeric materials and wood waste at the enterprises of machine building, chemical and woodworking industry. A device for crushing contains a charging hopper, a housing with limitation of the motion of material and a perforated bottom, above which fixed cutters are mounted with inclination, between which on the lay shaft downstream of the helix toothed movable cutters are mounted. A cavity is made above the raised ends of fixed cutters. The teeth of each movable cutter are located on the convex curve. The limiter of the motion of material is made in the form of vertical plates mounted on the nonworking surfaces of fixed cutters. The front wall of hopper is formed by two cylindrical surfaces, the connection of which is made inside the hopper in the form of sharp edge being parallel to the shaft axis, and the cylindrical surface of the rear wall of the hopper is located level with the upper edges of the plates of limitation of the material motion, those form a sharp angle with the vertical line, which intersects the axis of the shaft. The technical result consists in the increase of gripping capability of movable cutter and increase of crushing efficiency.

Description

Description of the invention

The device belongs to mechanical engineering, to devices for grinding loose materials, and can be used in machine-building, chemical and woodworking enterprises to grind metal shavings, wood waste and polymer materials.

A known device for crushing materials, which contains a loading hopper with cut-offs on its walls, a housing with sinuses and a perforated bottom, as well as fixed knives located inclined inside the housing, above which are installed two shafts with knives having teeth on a concave working surface (a .s. USSR 70. Mo1694214, VO2S18/06, BV. Mo44, 1991). The disadvantage of this device, taken as a prototype, is the location of the knife teeth on a concave surface, which leads to excessive gripping ability of the knives. Despite the improvements aimed at reducing it, the concave shape of the knife causes both a general increase in the forces of destruction of the material and an increase in their jump-like changes. With the concave shape of the knife, all its teeth are in contact with the stationary knives almost simultaneously, sharply increasing the load on the drive. This is facilitated by the 72 location of the plane of the fixed knives below the axis of the shaft, due to which the amount of material that falls under the moving knives increases. The inclination of the fixed knives eliminates this disadvantage only partially, since the main part of the length of the fixed knives is still located under the shafts. As a result, there are overloads of the drive, the uniformity of crushing is disturbed and its efficiency is reduced, especially at the beginning of crushing, when the hopper is filled with material. In addition, the plane of location of the material movement limiter coincides with the plane of location of the axes of the crusher shafts, due to which uncrushed material falls into the space between the rotors so deeply that it is difficult to grab it from there with knives. This material cannot be crushed, which also reduces the efficiency of the crusher.

The invention is based on the task of improving the shredding device by using a new shape of a moving knife, in which its gripping ability, initially extremely low (for this shape of the knife), can be increased and brought to the desired level by changing the curvature and dimensions of the knife, as well as for (3) due to the interaction of moving knives with structural elements that are consistent with their shape, which will ensure an increase in the efficiency of shredding.

The problem is solved by the fact that in a known device, which contains a loading hopper, a case with a material movement limiter, and a perforated bottom, above which knives are installed with an inclination, between which toothed movable knives are mounted on a horizontal shaft behind a helical line, and above the raised at the ends of the fixed knives there is a sinus, the teeth of the movable knife are located on a convex curve, which is given by the equation (22) where K is the radius of curvature, 0 хххх 0.05, г is the radius of the circle of the base of the movable knife, which is tangent to the cutting surface 3o fixed knives, Ф is an angle in radian measure that determines the position of the radius of curvature, and the front wall of the hopper is formed by two cylindrical surfaces, the connection of which is made inside the hopper in the form of a sharp rib parallel to the axis of the shaft, and the cylindrical surface of the rear wall of the hopper is coupled with the plane of location of the limiter of the movement of the material, which forms an acute angle with the vertical, crossing the axis of the shaft. "

The teeth of the movable knife are located on a convex curve, thanks to which the gripping ability of the knife Z is maximally reduced compared to the prototype. When rotating such a knife, its teeth alternately capture from below only individual fragments of material with which they are in direct contact. The main mass of material from" continues to remain in the hopper, without being drawn into the body, without creating jamming and overloading of the drive. The teeth of the convex-shaped knife alternately also contact the fixed knives, due to which the material is crushed gradually, and both the forces of its destruction as a whole and the jumps of these forces on the shaft are reduced.

Therefore, the location of the teeth on a convex curve radically eliminates the shortcomings of the prototype and increases efficiency and crushing. The curve is given by the equation sho Be M zh Y bo (where K is the radius of curvature, 0 5 Kk 05 0.05, g is the radius of the circle of the base of the moving knife, tangent to the cutting surface of the fixed knives, Ф is the angle in radian measure, which determines the position of the radius of curvature) because at Kk -0 со it turns into the equation of the involute of a circle in polar coordinates:

Ko - gm Fo

As you know, the involute of a circle (involute) has the property that the tangent to it at any point 22 makes an angle of 902 with the tangent to the involute. Therefore, if the involute serves as the circle of the base of the knife, and the same involute is there

GF) is tangent to the plane of the fixed knives, then the cutting edge of the moving knife, which is involute, during the rotation of the knife constantly crosses the plane of the fixed knives at an angle c: -902, that is, it does not contribute to the capture of the material. Therefore, the gripping capacity of such a knife is determined only by the presence of teeth located on the involute, that is, it can be made minimal. With such a shape of the knife, it is necessary not to reduce its 60 gripping ability from a known large one, as is done in the prototype, but on the contrary, to increase it from a known small one, achieving such a result that the crushing efficiency will be maximum. For this purpose, the radius of the evolute in the equation of the curve has an exponent of the degree 14-KF. By assigning the value K»0, it is possible to reduce the curvature of the moving knife, thus reducing the angle a of the interaction of the cutting surface of the knife with the plane of the fixed knives. At the same time, the gripping ability of the knife increases, as it becomes less curved. In addition, due to the reduction of the curvature of the knife while maintaining its angular size (which is determined by the rotation of the knives on the shaft along the helical line at an angle of y-1202 relative to each other), the radius of the knife and the number of teeth on it increase (with an unchanged radius g and unchanged tooth sizes ), which also increases the gripping ability of the knife. Thus, the specified equation provides a continuous transition from an involute to a logarithmic curve, and due to the increase of only one parameter - the K coefficient, with a corresponding increase in the gripping ability of the knife and the efficiency of crushing. For example, at x -0.05, the angle a between the tangent to the curve and the location plane of the fixed knives decreases on average to 772, and the radius of the knife increases by 1.4 times compared to the knife, which is given by the involute (0/0 Хх -0), the more the capturing power increases. The lower the strength of the material subject to crushing, the greater should be the coefficient k. But the value of K-0.05 is the upper limit, since at x 20.05 the destruction forces increase unreasonably, and the efficiency of crushing decreases. At the same time, the radius of the knife K is excessively large compared to the radius of the circle of the base of the knife g, and the strength of the base of the knife is not ensured. Therefore, when they are 20.05, an unacceptable contradiction arises between the given equation of the curve and the set task of increasing the crushing efficiency.

At the same time, the change range of 0 xxx 0.05 is quite sufficient to ensure effective crushing of loose materials. Since the circle of the base of the moving knife is tangential to the cutting surface of the stationary knives (this is a condition for the equation of the guide curve of the knife), this entire surface is located above the axis of the shaft, and not below it, as it was in the prototype. As a result, the disadvantage associated with an excessively deep failure of chips inside the housing without crushing is eliminated. For this reason, the increase in crushing forces is eliminated, which increases the efficiency of crushing.

The front wall of the hopper is formed by two cylindrical surfaces, the connection of which is made inside the hopper in the form of a sharp rib, parallel to the axis of the shaft, with the aim of limiting the amount of material drawn by the moving knives onto the plane of the stationary knives, as well as providing partial or complete separation of this material from its main mass in the hopper. The presence of the specified sharp edge is due to the fact that the movable knife of a convex shape during its rotation displaces the material on the stationary knives radially from the shaft and (5) presses it against the wall of the hopper. The material is compacted and can become jammed between the moving knives and the front wall of the hopper. Therefore, with the convex shape of the knife, it is necessary to ensure that the teeth capture such an amount of material that would be almost completely crushed when the moving knife passes between the stationary ones, and only a small remainder of the material would enter the sinus, eliminating jamming. This and (ee) is achieved by the specified shape of the front wall of the hopper, thanks to which the main mass of the material is kept from falling onto the stationary knives immediately, without breaking, and the sharp edge helps to separate the part of the material captured by the teeth from its main mass. In this way, a certain dosage of the material entering the (ee) crushing is achieved. Even if separation does not occur, when the movable knife interacts with the rib, the material would be pulled from the end teeth of the knife and transferred to the rear part of the movable knife, where it would be captured by the teeth of the following movable knives closest to the center of rotation, and would be destroyed with a smaller shoulder of effort. Thus, the front wall of the hopper, formed by two cylindrical surfaces, the connection of which forms a sharp edge inside the hopper, in accordance with the convex knives of a toothed shape, excludes excessive tightening of the material to the crusher, ensures its partial rupture and pulling it from the ends of the moving knives, thanks to which overloading of the drive is eliminated and the efficiency of crushing is increased.

The lower part of the front wall of the hopper in the section from the sharp edge to the sinus forms such a narrowing gap with the circle of rotation - from the rotor. The interaction of the convex toothed knife with this part of the wall increases the gripping ability of the device, since the material captured by the teeth freely enters the wide gap "under the rib" and then compacts as the knife rotates. At the same time, thanks to the sharp edge, not the entire mass of material is pulled into the gap, but only that part of it that is torn off by the teeth during their interaction with the edge. The shape of the bunker as a whole contributes to effective separation, as it is formed by cylindrical surfaces, not flat ones. When loading a ball of shavings into such a hopper, the area of the ball's contact surface with the walls of the hopper is maximal. Accordingly, the amount of material that rubs against the walls during the possible rotation of the ball in the hopper due to the rotation of the rotor also increases. As a result, the entire ball is better (ee) kept from unwanted rotation precisely by cylindrical rather than flat surfaces. Sl 50 prevents the rotation of the ball and the sharp edge against which the part of the material that is captured by the teeth rests. Therefore, it is precisely the rupture of the material on the sharp edge that occurs, and not the useless rotation of the ball in the hopper. Since the convex shape of the serrated movable knife just contributes to such a rotation, to eliminate this drawback, making the walls of the hopper cylindrical in combination with a sharp edge on the front wall of the hopper is absolutely necessary. Thus, the high efficiency of crushing material with a knife of a convex shape is ensured only with the combined use of such a knife with a hopper of the specified shape and a sharp edge inside it. Taking into account the deformation of the ball, the guide lines of the bunker walls can be both logarithmic curves and circles of the appropriate radius. eat) The cylindrical surface of the back wall of the hopper is coupled with the plane of the location of the limiter of the movement of the material, because such a coupling ensures an unimpeded sliding of the material along the back wall, and then - along the edges of the plates of the limiter - to the crusher shaft itself. The location plane of the limiter forms an acute angle with the vertical, crossing the axis of the shaft, because only under this condition the limiter will not allow the material to fall on the non-working surface of the stationary knives, from where the material cannot be captured by the convex movable knives. Therefore, it is the correspondence between this shape of the knife and the location of the limiter that ensures complete and effective shredding. The limiter is made in the form of identical plates, close in shape to sectors 65 of a circle, which are installed vertically and parallel to each other on the non-working surfaces of the stationary knives and fixed from the outside on the crusher body with bolted connections.

Fig. 1 shows a crushing device, side view in section, with the construction of a moving knife according to the given equation of the guide curve at K-0.03.

Fig. 2 shows a group of three movable knives, built according to the involute circle of the base of the movable knife (with a minimum value of Kk -0), installed on the shaft along a helical line with rotation relative to each other at an angle of y-1209.

Fig. 3 shows the same group of movable knives built according to a given guide curve with a maximum value of Kk of 0.05.

The shredding device (Fig. 1) contains a loading hopper 1, a case with a material movement limiter 2 70 and a perforated bottom 3, above which fixed knives 4 are installed with an inclination, between which toothed movable knives 6 are mounted on a horizontal shaft 5 along a helical line, and above the raised ends of the fixed knives there is a sinus 7. The teeth of the movable knife are located on a convex curve (Fig. 2, Fig. 3), which is given by the equation v-t, la Fo de K - radius of curvature, 0 xx xx 0.05, g - the radius of the circle of the base of the moving knife, which is tangent to the cutting surface of the fixed knives, Ф is the angle in radian measure, which determines the position of the radius of curvature, and the front wall 8 of the hopper is formed by two cylindrical surfaces, the connection of which is made inside the hopper in the form of a sharp rib 9, parallel axis of the shaft, and the cylindrical surface of the back wall 10 of the hopper is conjugated with the plane of the location of the limiter of the movement of the material, which forms an acute angle with the vertical, crossing the axis of the shaft.

The crushing device works as follows. The material loaded into the hopper 1 is captured by the movable toothed knives 6 and destroyed due to the deformation of the cut when these knives pass through the grooves between the stationary knives 4. The crushing product is removed from the crusher through the perforated bottom 3, and the material that has not reached the required size is picked up from the bottom by the teeth knives and is crushed a second time when these knives pass between stationary knives on the ascending part of the rotor rotation circle. Due to the fact that the teeth of the movable knife are located on a convex curve, during its rotation, the knife captures the material from below from the hopper not with all teeth at once, but with each tooth in turn. Also, alternately, the teeth of the convex movable knife come into contact with the stationary knives. Thus, with the convex shape of the toothed knife, not only the alternating contact of each such knife with the fixed knives is achieved due to the location of the movable knives on the shaft along the ee) helical line, but also the alternate contact of each tooth of the knife with the fixed knives. Such an interaction of moving knives with fixed ones is realized only with a convex shape of a toothed moving knife. Since the material is captured and crushed alternately by each tooth, the forces of destruction of the material are reduced, ee) overloading of the drive is eliminated, the crushing process proceeds evenly, without large jumps of forces on the shaft, and the crushing efficiency increases. Due to the fact that the guide curve of the moving knife (Fig. 2, 3) b z5 is given by the equation рч-в-т, M ж Fo (where К is the radius of curvature, 0 хх Ж 0 0.05, r is the radius of the circle of the base of the moving knife tangent to the cutting surface of fixed knives, Ф is the angle in radian measure, which determines the position of the radius of curvature), the efficiency of " 420 shredding of various materials is increased by changing the gripping ability of the moving knife - with the appropriate selection of the coefficient K. At the same time, the gripping ability changes and is brought to required not only by curving or straightening the knife, but also by changing the radius of the knife and the number of "" teeth on it. At minimum K-O, the guide curve of the knife is an involute of the circle of the base of the knife. When rotating such a knife, its guide line is constantly intersects the plane of location of fixed knives at an angle of А-90 o (Fig. 2), that is, the curvature of the knife does not contribute to the capture and destruction of the material at all. For this, the involute, that is, the circle of the base of the knife, is tangent to the plane p location of fixed knives. The gripping ability of such a knife is minimal, and it is provided only by teeth that interact with the front wall of the hopper and stationary knives, crushing the material. Such a knife is advisable to use for effective (ee) shredding of materials with high strength properties (chips of high-alloyed steels and alloys with 50 non-ferrous metals). As k increases, the angle A decreases, that is, the guide curve of the moving knife crosses the plane of the stationary knives already at an acute angle (Fig. 3), due to which the gripping ability increases

IR e) knife. At the same time, the radius of the knife and the number of teeth on it increase (if the radius of the base h, the dimensions of the tooth and the angle y-1202 of the location of the knives on the shaft remain unchanged), which also increases the gripping ability.

As a result, the moving knife captures and destroys a larger amount of material than at k -0. It is advisable to increase k to increase the efficiency of destruction of materials with less high strength properties (thin

Gee! metal shavings, plastic film and sheet waste, thin wood waste, etc.). At the maximum " -0.05 (fig. 3), the gripping ability of the knife is increased so much that already at "20.05 it becomes excessive. When rotating such a knife, due to its smaller curvature and larger radius, the forces of capturing and destroying the specified materials become such that they can cause an overload of the drive. 60 At the same time, the radius of the knife is unacceptably large compared to the radius g of the base of the knife, which is unacceptable for maintaining the strength of the knife. Thus, in the given equation of the curve, the change of the coefficient k only within the specified limits - from О to 0.05 - ensures effective crushing of various materials. Since the cutting surface of the fixed knives is located above the axis of the shaft, the material is crushed at smaller angular movements of the moving knives and is not drawn deep into the casing without crushing. As a result, the material is destroyed with less b5 effort, and the danger of jamming of the rotor is eliminated when the unshredded material is compressed between the convex knives and the wall of the hopper located at an acute angle with the edge 9, which increases the crushing efficiency. Therefore, the combination of a toothed knife of a convex shape with the arrangement of the plane of the fixed knives above the axis of the shaft is necessary to solve the problem of the invention. The ball of shavings in the hopper due to its own deformation takes the shape given by the cylindrical walls 8 and 10 of the hopper, and adheres to them with its entire surface. Therefore, when the rotor rotates, the ball, indicating the maximum possible friction, does not rotate in the hopper, as a result of which the moving knives effectively grab the shavings from the lower part of the ball. This is facilitated by the sharp edge 9, which prevents the ball from rotating in the hopper under the action of the rotor. As a result, the lower part of the ball is evenly and efficiently destroyed, and the ball itself gradually falls down in the hopper under the influence of gravity and is completely crushed. The material captured by the teeth during the interaction of the moving knife with a sharp edge /o Breaks away from its main mass held in the hopper, or is pulled from the end of the moving knife, falling onto its occipital area. Here, the material is captured by the teeth of the following moving knives, as a result of which the crushing forces at the ends of the moving knives decrease, and on the teeth closest to the shaft - increase, which reduces the jumps of forces on the shaft, eliminates overloading of the drive and increases the efficiency of crushing. The material, partially held by the front wall of the hopper, at the same time can /5 Freely slide down its rear wall 10, and further along the surface of the limiter 2 due to the fact that this wall is conjugate with the plane of the location of the limiter. As a result, the material penetrates unhindered to the teeth of the moving knives closest to the shaft and is destroyed with less effort. In general, the shape of the front and back walls of the hopper, in combination with the conjugation of the back wall of the hopper with the plane of the location of the limiter, contributes to a greater load on the teeth of the convex knives closest to the shaft and a smaller load on the end teeth of these knives. This is facilitated by the sinus 7, into which the material from the end of the moving knife can penetrate, which eliminates jamming. Thus, matching the shape of the hopper with the shape of the convex serrated movable knife reduces the destruction forces both in general and the jumps of these forces when moving from one movable knife to another during the rotation of the rotor, which increases the efficiency of crushing.

Thus, the location of the teeth of the movable knife on a convex curve. given by the specified equation, in which only one parameter changes the capture capacity from the minimum to the desired one according to the crushing conditions, in combination with the proposed shape of the hopper, a sharp edge inside it and a limiter i) of material movement, ensures an increase in crushing efficiency.

Claims (1)

The formula of the invention is a device for crushing, which contains a loading hopper, a body with a material movement limiter and a perforated bottom, above which fixed knives are installed with an inclination, between which toothed movable knives are mounted on a horizontal shaft behind a helical line, and above the raised ends of the fixed of knives is made (is) of 5 Cavity, which differs in that the teeth of each movable knife are located on a convex curve, which is given by the equation: v-t, la Fo de K - radius of curvature, "Ox k 0.05 in I . І І - г - the radius of the circle of the base of the movable knife, tangent to the cutting surface of the fixed knives, Ф - the angle in radian measure, which determines the position of the radius of curvature, . . - and the limiter of the movement of the material is made in the form of vertical plates installed on the non-working surfaces of the stationary knives, the front wall of the hopper is formed by two cylindrical surfaces, the connection of which is made inside the hopper in the form of a sharp rib parallel to the axis of the shaft, and the cylindrical surface of the back wall of the hopper is located level with the upper edges of the plates of the limiter of the movement of the material, which form an acute angle with the vertical, crossing the axis of the shaft. se) (ee) 1 IR e) name) 60 b5