RU2537497C2 - Rotary swirling pulverising mill - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: rotary swirling pulverising mill is intended for pulverising of hard material to preset dispersity. Its can be used in food and chemical industry, etc. Mill comprises vortex grinding chamber with cooling water jacket and shaped side surface. The latter has grooves shaped to rectangular trapezoid, with blind bottom and classifying cover. Coaxial swirling chamber is arranged above grinding chamber and confined from below by sais classifying cover. Two hollow rotors are fitted one into the other and provided with variable-section vanes secured between discs of one rotor. Ring with at least 8 bores arranged tangentially to peripheral circle is fitted in second rotor with blind top and bottom discs. Feed pipe lower edge height relative to rotor bottom disc can be adjusted while second outer rotor OD makes at least 0.71 of vortex chamber ID.

EFFECT: grinding of material highly sensitive to heating, required ground particle size.

3 dwg

Description

The invention relates to rotary vortex mills designed for grinding solid materials.

A device for cascade grinding is known - a vortex mill [RF Patent 2386480], containing a vortex grinding chamber with a profiled side surface, with a blank bottom and a diaphragmed lid, a coaxial unwinding chamber located above the grinding chamber, bounded below by a diaphragmed lid of the vortex chamber adjacent to the side adjacent to a surface with a product outlet pipe on the periphery and an upper cover through which an inlet pipe passes through the center with an abutment, immersed in the grinding chamber with its lower end, and a device for swirling the carrier medium and initial particle acceleration. To swirl the carrier medium and initially accelerate the particles, a hollow rotor of a centrifugal fan with a blind lower disk, a diaphragmed upper disk and blades fixed between these disks is used, located coaxially inside the vortex grinding chamber, under the particle inlet pipe, so that the height of the lower cut of the input pipe relative to the lower the rotor disk is adjustable, and the outer diameter of the rotor is not more than 0.71 of the inner diameter of the vortex chamber.

The disadvantage of this device is the low content of the desired fraction due to sticking of the side profiled surface due to the long presence of under-ground material in the grinding chamber and heating of the profiled side surface of the grinding chamber.

The device according to the patent of the Russian Federation 2057588, 1991, V02C 19/06, contains a vortex grinding chamber with a profiled side surface, with a blank bottom and a diaphragmed lid, a coaxial untwisting chamber located above the grinding chamber, bounded below by a diaphragmed vortex chamber cover adjacent to it a lateral surface with a tangential outlet pipe of the product and an upper cover through which the inlet pipe passes through the center with the abutment, the lower end immersed in the grinding chamber below the level of the opening in the diaphragm th cover. To swirl the carrier medium and initially disperse the particles, a jet of expanding compressed gas is used, which is introduced through the tangential nozzle in the side surface of the vortex chamber. The crushed material is introduced through the input pipe and, being involved in rotation, is drawn into the input stream, and initial acceleration is obtained in it. This leads to increased wear of the meeting area of the side surface of the chamber with the inlet stream.

A disadvantage of the known device for the implementation of cascade grinding is the high level of energy consumption, characteristic of all gas-dynamic grinders (jet mills), in which the crushed material is accelerated only in the gas stream due to the lag of particles from the stream, as well as the need for preliminary grinding of material particles.

A known device for grinding - centrifugal crusher [and.with. USSR 990295], containing a hollow rotor with nozzles for accelerating the crushed material before it collides with the grinding surface, on which small eddies arise due to the gear lining due to the collision of particles and the carrier medium against the lining.

A disadvantage of the known device is that the crushed material is quickly removed from the grinding volume, without reaching a fine grinding.

The objective of the present invention is to increase the yield of a monodisperse product of a given fraction, to reduce the heating of the product during the grinding process by increasing the technical capabilities of the mill.

To accomplish the tasks it is proposed to twist the carrier medium, preliminary grinding and initial particle acceleration in a hollow rotor having variable cross section vanes.

Particles accelerated mechanically due to interaction with the rotor are ejected from it onto the inner surface of the second rotor, which has at least 8 grooves along the tangent to the circle, and the pressure created by the internal rotor pushes the carrier medium together with the pre-ground material through the grooves of the second rotor (external) , while the softest particles (already crushed to the desired fraction in the inner rotor, as well as between the two rotors) are immediately removed by a swirl from the grinding chamber into the accelerating chamber, which allows avoids excessive disintegration and increased product heating. At the exit of the carrier medium with the material being ground from the second (external) rotor, a vortex is created, which carries the material to the periphery of the grinding chamber, on which a lining with grooves having the shape of a rectangular trapezoid, in which the output side of the trapezoid is located at an angle of 90 ° relative to its base, is installed, on which, in turn, small vortices arise and harder material is crushed due to repeated interaction with the lining, water is used to reduce the heating of wear-resistant inserts (lining) ubashka cooling.

Figure 1 presents a General view of a rotary vortex mill of fine grinding, figure 2 - section aa, figure 3 - section bb.

The device comprises a housing (1), an inlet pipe (2) for supplying ground material and air, an acceleration chamber (3), a diaphragmed cover (classifier) (4), a water cooling jacket (5), a device from two rotors (6), wear-resistant inserts (lined side surface) (7), grinding chamber (8), shafts (9), pulleys (10), outlet pipe (11).

The device operates as follows.

The design of two rotors (6) is driven by an electric motor that transmits torque through a belt drive to the rotor drive. The rotor drive consists of two shafts (9) installed one inside the other. Pulleys of different diameters (10) are installed on the shafts to create different speeds (the inner rotor rotates at a higher speed than the outer one to create the pressure of the carrier medium). When the rotors rotate in the region of the hole, a rarefaction zone is formed in its upper disk. Air (carrier medium) is sucked into this area through the inlet pipe (2) from the external space. The crushed material is fed into the same area through the inlet pipe. The swirling air stream with the material to be ground leaves the first rotor (inner) on the inner surface of the second (outer) rotor. From the second rotor, the material is discarded to the periphery of the grinding chamber (8), where it interacts with its lined side surface (7). In this case, the material particles move along polygonal paths determined by the geometry of the lining. If the rotational speed of the rotor is sufficient to overcome the particles of the threshold grinding speed upon impact, the particles are divided. The resulting fragments are mixed with the medium coming from the rotor, accelerated by it, and again participate in the interaction with the lining. Air and small particles exit the vortex chamber through the upper classifier cover (4) into the booster chamber (3) and then through the tangential branch pipe (11) are discharged to any precipitating device. The diaphragmed top cover of the vortex (grinding) chamber in this case serves as a classifier. With an increase in the gap between the lower end of the inlet pipe and the continuous lower disk of the fan rotor, the air flow increases, which serves to transport the crushed material and remove excess heat from the grinding chamber, and to prevent the lining from heating, a water jacket is used to cool the grinding chamber (5).

Claims (1)

A cascade grinding vortex mill, comprising a vortex grinding chamber with a profiled side surface, a blank bottom and a diaphragmed lid, a coaxial untwisting chamber located above the grinding chamber, bounded below by a diaphragmed vortex chamber lid adjacent to it with a side surface with a peripheral product outlet pipe and the upper lid, through which the inlet pipe passes through the center with the abutment, immersed in the grinding chamber with the lower end, and the spinning device is non-existent medium and initial particle acceleration, characterized in that for more efficient grinding, the design of the vortex grinder consists of two rotors, where the first internal rotor consists of two disks, in the upper disk there is a window for supplying raw materials, between the disks fixed blades of variable cross section with an input edge wider than the output, twisting the carrier medium, creating pressure, as well as performing preliminary grinding, the second rotor, external, consists of a lower solid disk and an upper one with a window, between the disks installed a ring has been introduced that has at least 8 grooves along a tangent to a circle, passing material with a carrier medium through it, evenly distributing it throughout the grinding chamber and creating a vortex in it to create small vortices on the surface of the grinding chamber, for faster and finer grinding of the material a lining having the shape of a rectangular trapezoid, in which the output side of the trapezoid is at an angle of 90 ° relative to its base, to reduce the heating of wear-resistant inserts of the lining dyan shirt cooling.

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