SU1087589A1 - Hammer mill for treating fibrous cellulose-containing material - Google Patents

Abstract

1. A MOLOTKOVYY MILL FOR A FIBER CELLKSHOZOZERTSODZHATSHY MATERIAL, including a housing with a receiving neck, a hammer rotor installed in the housing, a sieve dividing the volume of the housing into the working and receiving chambers, and a means for deforming the air flow material in the grinding zone, a distinct or different pattern, a separate grinding unit. , in order to increase the efficiency of the grinding process by changing the speed of the air-material flow relative to the peripheral speed of the hammers, the means for deforming are made in the form of at least od Nogo aerodynamic element mounted in the receiving space at the outer, surface of the screen and provided with a regulator of its position relative to the screen. 2. Mill according to claim 1, characterized in that the means for deforming the air-material flow is made in the form of a blade.

Description

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c, s The invention relates to devices for grinding various fibrous cellulosic materials, intended for use in the pulp and paper industry for grinding pulp and macular sheet material and can be used in other industries, for example, in the chemical industry, in agriculture. Grinders are known, the principle of which is the cracking, abrasion, spreading, cutting, or "cracking" of a material. The use of such apparatus for grinding fibrous materials leads to a reduction in the size of individual fibers, as well as the integrity of their structure. Deterioration in fiber quality is the cause. reducing the grade of the semifinished product. The waste paper thus crushed can only be used to produce the lowest grades of paper. These defects are deprived of hammer mills, in which grinding occurs under conditions of free impact. In this case, the destruction occurs only in the weakest points. Materials with a fibrous structure are destroyed in the bonding places between the fibers, as well as between aggregates of individual fibers. Therefore, the integrity of the fibers themselves is not broken. Closest to the invention is a hammer mill for fibrous cellulose-containing material, comprising a housing with a receiving neck, installed in the housing of a hammer rotor, a screen separating the volume of the housing to the working and receiving chambers, and means for deforming the air-material flow in the grinding zone. An additional vortex chamber, which contributes to the displacement of the center of the air vortex and organizes the work of the mill according to the diametrical fan I scheme, serves as a means for deforming the center of the air vortex. During the operation, the rotating hammer rotor creates an air vortex in the working area, which picks up the material and gives it a circular motion . As a result, when: a certain degree of grinding of the material, a sufficiently stable air-material suspended layer is formed, having a direction of movement and rotation frequency close to the direction and frequency of rotation of the hammer rotor. At the same time, due to the equality of the speeds of movement of the material and hammers, there is a decrease in the effectiveness of the grinding effect of the hammers on the material and, accordingly, the productivity of the grinding process decreases. Fibrous sheet material (cellulose, paper, trp) refers to materials with low density, easily weighed air flow, which additionally contributes to the formation of a rotating air-material layer and reduce the grinding effect of hammers. However, the displacement of the center of the air vortex with the help of the vortex chamber device does not violate the integrity of the vortex, the stability of the air material layer, but in some cases allows only to order the air mode of the mill. In addition, the presence of a vortex chamber complicates the design of the mill housing. The purpose of the invention is to increase the efficiency of the grinding process by varying the speed of the air stream relative to the speed of the hammers. The target is achieved by the fact that in a hammer mill for fibrous cellulose-containing material, comprising a housing with a receiving neck, a hammer rotor installed in the housing, a sieve dividing the volume of the housing into the working and receiving chamber, and means for deforming the air flow material into the grinding zone, the means for deforming is made in the form of at least one aerodynamic element, installedHo .ro in the receiving chamber at the outer surface of the sieve and equipped with its positioner relative to About the screen, the means for deforming the air-material flow is made in the form of a blade. The installation of the aerodynamic element at the outer surface of the sieve allows changing the magnitude and direction of the air flow rate in the working area of the hammer mechanism due to the occurrence of an overpressure area when air flows onto the frontal part of the blade and a rarefaction area when air flows from the tail part of the blade. Under the action of overpressure, a change in the direction of the air velocity of the air-material flow relative to the velocity vector of the ends of the rotor hammers occurs and the air-material flow deforms towards the action of the hammers. In this case, the total speed of its installation is less than the speed of the ends of the rotor hammers, which leads to an intensification of the grinding process. The vacuum on the tail of the blade facilitates the evacuation of particles through a sieve. The possibility of adjusting the radial clearance between the blade and the sieve, as well as the angle of rotation of the blade, allows one to choose its optimum position relative to the screen, depending on the type of material being crushed and the grinding mode. FIG. 1 is a view of a hammer mill, a section J in FIG. 2 — node I in FIG. 1. The mill has a housing 1 with a reception 2 and a discharge 3 mouths. Inside the case on the drive shaft 4, a hammer rotor is fixed, made in the form of a drum 5 with hinged pivots under hammers 6. A hammer rotor is installed in a working chamber formed by decks 7 and a semi-cylindrical screen 8 for separating the material to be ground. To remove the material to be comminuted from the receiving chamber 9, a centrifugal fan is used, the suction inlet of which is connected to the discharge port 3 of the mill by a transition pipe (not shown). In the receiving chamber 9, at the outer surface of the sieve 8 kg, the aerodynamic element 10 is replen, for example, a profiled blade. The aerodynamic element can also be made, for example, in the form of a flat plate installed at an angle to the plane tangent forming a cylindrical screen in the form of a cylindrical segment of different curvature. The aerodynamic element 10 is provided with a regulator of its position relative to the sieve, for which the ends of the aerodynamic element 10 can be provided with studs 11, which are inserted into the through slots 12 cut through both sides of the housing. The fixing of the element can be accomplished with the help of thumb nuts 13, which are screwed onto the ends of the studs protruding from the body. Prior to the start of operation, the aerodynamic element 10 is set to the desired position (with a certain clearance and at a certain angle) and fixed with thumb nuts 13 on both sides of the body 1 of the hammer mill. Then the mill is turned on and a centrifugal fan is used to remove the ground material. Thereafter, through the feed nozzle 2, the material to be milled is fed into the mill. As it progresses, the material enters the zone of action of the rotating hammers 6 and collapses. Since the material is subjected to blows of hammers b, being in a suspended state, its destruction occurs in places of weak junctions. For fibrous materials such as cellulose, paper, etc., these places are contacts between individual fibers and FOLOCHON1 aggregates. Under the action of blows from hammers 6, the material to be ground is thrown to the decks 7. and sieve 8 bounding the working chamber. Attack the decks 7. The material bounces back into the zone of action of the hammers 6 and the grinding continues. When meeting with a sieve, the material is tested for passage. If the particle size is smaller than the size of the sieve cell, then it passes through the sieve and the air flow created by the fan is removed from the mill. If the cell size is smaller than the particle size, the latter bounces off the sieve and is subjected to grinding again. At a certain grinding stage, a grinding regime occurs when the bulk of the material is weighed by a swirl and forms an air-material layer. The part of the air layer penetrating into the receiving chamber 9 runs onto the frontal part of the aerodynamic element tO. This creates a pressure front and the air flow is diverted towards the center of the hammer rotor. Together with the airflow, the weighted

there is material in it. The deviation of the air-material layers from the uniform circular trajectory causes a change in its speed, which in this case is significantly different from the peripheral speed of the ends of the hammers 6 both in magnitude and in direction. As a result, the material entering the zone of action of the hammers 6 is further crushed. When running down the air flow from the tail section of the aerodynamic element 10, air pressure is directed from the center of the mill to the periphery. The pressure enhances the suction effect of the fan and helps to improve the evacuation of crushed particles from the working chamber.

The proposed mill has passed laboratory tests.

Aerodynamic blade in the test mill is installed at the outer surface of the sieve at a distance of 5 mm at a research angle at an angle of 10 to the incident air flow. Waste paper and sulphate pulp were crushed. The diameter of the screen perforation in both cases was 6 mm. The amount of material being ground simultaneously is 0.5 kg. The frequency of revolutions of the hammer rotor is 2500 rpm.

The test results of the proposed and known mills are shown in the table.

The table shows that the use of the proposed mill allows to increase its productivity in comparison with the known one. So, when grinding newspaper waste paper by reducing the grinding time, the productivity of the device increased by 70-50%, and when grinding sulphate pulp - by 60-40%. In addition, the proposed design improves the uniformity of the grinding material.

Newspaper waste paper. Time of full grinding, С

Estimated capacity, kg / h

Sulphate pulp. Time of complete dissolution, C

Estimated capacity, kg / h

6-8

10-12

300-225

180-150

7.5-11

12-15

240-170

150-120

Claims (2)

1. HAMMER'S MILL FOR A FIBROUS CELLULAR CONTAINING MATERIAL, including a housing with a receiving neck, a hammer rotor installed in the housing, a sieve separating the body volume into a working and receiving chamber, and means for deforming the air-material flow in the grinding zone, characterized in that, for the purpose of ^1, increasing efficiency grinding process by changing the speed of the air-material flow relative to the peripheral speed of the hammers, the deformation tool is made in the form of at least one aerodynamic e ementa installed in the receiving chamber at the outer, surface of the sieve and fitted with its position relative to the regulator sieve. 2. The mill according to claim 1, characterized in that the means for deforming the air-material flow is made in the form of a blade. >