RU2209674C2 - Apparatus and jet-type grinding rotor milling chamber - Google Patents

Abstract

FIELD: grinding equipment. SUBSTANCE: milling chamber has casing with two milling sections communicated with one another via tangential channel, breaking member mounted inside tangential channel, rotors positioned in each of said sections and equipped with speeding-up blades fixed on disks, and charging openings formed in upper cover of casing and discharge opening formed in lower cover of casing, centrally of tangential channel. Charging openings are made in the form of nozzles and axially aligned with respective rotors. Additional discharge opening is formed in casing lower cover centrally of tangential channel in axially aligned relationship with discharge opening. Bushing used as breaking member is positioned in additional discharge opening and is made in the form of truncated cone inserted with its smaller diameter into tangential channel. One ends of blades are arranged along outer perimeter of disk and other ends define inner surface having radius at least equal to radius of charging opening. Distance between blade ends along perimeter exceeds distance between blade ends defining inner surface. EFFECT: increased efficiency and simplified construction. 2 cl, 1 dwg

Description

 The invention relates to the field of fine and ultrafine grinding of materials of different hardness and can be used in various industries, for example, construction, mining, chemical, fuel.

 There are various methods of grinding material using gas: due to the impact of a gas suspension on an obstacle [Sidenko P.M. Grinding in the chemical industry. -M .: Chemistry, 1977, p.215] or due to the collision of particles of two counter flows [Sidenko P.M. Grinding in the chemical industry. M. Chemistry, 1977, p.217]. Acceleration of gas suspension is carried out in nozzles [Sidenko P.M. Grinding in the chemical industry. -M .: Chemistry, 1977, p. 228), as well as using centrifugal acceleration [US Pat. USA 2981489, 1961, NKI 241-275].

 Various methods of grinding material correspond to grinding chambers of various designs.

 Known [ed. St. USSR 952321, В 02 С 07/08] a grinding chamber in the form of a casing with two grinding sections interconnected by a tangential channel, with each section having a rotor with accelerating vanes and a loading nozzle, and in the tangential channel there is an unloading nozzle equidistant from the axes rotor rotation.

 With this design of the grinding chamber, the relative loading speed of the crushed material is 300-400 m / s and there is a breakthrough of large particles, which can be from 2 to 5%. This is due to the fact that during the exit of the material from the loading nozzle, it is separated: fine fractions, due to their lower inertia, fall on the rotor faster and leave it faster, and large particles that do not fall into the grinding zone (tangential channel) are pressed by centrifugal force to the wall of the casing and move in a circle with the air flow, and then return to the tangential channel, having a speed an order of magnitude lower than the rate of descent of particles from the rotor, which reduces the efficiency of destruction. As a result, the resulting product has an insufficiently narrow particle size distribution.

 Known [ed. USSR 1076138, В 02 С 07/08] a grinding chamber, in which, in order to improve the quality of the crushed product in terms of particle size distribution, the following structural changes were made: the tangential channel is placed on the outside of the chamber and baffle plates are installed at an angle to each other. However, this design is too energy intensive.

 In order to reduce the energy intensity, another design of the grinding chamber was developed in the form of a housing with two grinding sections connected by a channel, which is directed tangentially to the inner side surface of each section, and the baffle plates are placed on opposite walls of the channel [ed. St. USSR 1577827, B 02 C 13/14].

 However, when grinding using this design, the size range of the resulting product is very wide, since it is mainly determined by the nature of the material being ground.

 The problem solved by the claimed invention is the ability to control the range of grinding.

 To achieve the specified technical result, the following jet-rotor grinding grinding chamber is proposed.

 The grinding chamber includes a housing with two grinding sections communicating with each other by a tangential channel in which a baffle element is located, rotors with booster blades mounted on disks placed in each section, loading holes in the upper case cover and an unloading hole in the lower case cover in the center tangential channel, and according to the invention, the loading holes are made in the form of nozzles and are located coaxially with the corresponding rotor, and in the center of the tangential channel coaxially with the discharge hole A hole in the bottom case cover has an additional discharge opening in the top case cover, inside of which there is a sleeve, which is made in the form of a truncated cone, immersed in a tangential channel with a smaller diameter, at least 0.10 of its depth, while the disk, one ends of the accelerating blades are located on the outer perimeter of the disk, and the other ends form an inner circle whose radius is not less than the radius of the loading hole and the distance between the ends of the blades along The diameter is at least twice as large as the distance between the ends of the blades forming the inner circle. The blades can be made in the form of long and short rectangles that alternate with each other, and one end of both blades is located on the outer perimeter of the disk, and the radius of the circle described by the other end of the short blades is at least half of the radius of the circle described by the other end of the long blades.

 Distinctive features of the inventive grinding chamber are in the form and number, as well as the location of the loading and unloading holes relative to the rotors and each other, in the presence of a baffle element in the form of a conical sleeve immersed in the tangential channel, in the distribution of the blades on the disks in a certain way.

 The presence of loading holes precisely above the centers of the rotors of the grinding sections ensures that the gas suspension is fed directly into the chamber into the vacuum zone formed during the rotation of each of the rotors, i.e. contributes to the grinding step of the barrier in the form of a disk.

 The location of the discharge openings in the tangential channel coaxially opposite each other provides a powerful vortex in the collision of flows dispersed in its grinding sections, i.e. contributes to the destruction in the stream, and the implementation of the breaker element in the form of a conical sleeve immersed in the tangential channel provides along with the destruction of the barrier narrowing the size range of the obtained crushed material due to the separation of particles into two streams.

 The arrangement of the blades on the disk in accordance with the requirements described above gives the aerodynamic flow a similar motion to the flow in the nozzle, i.e. contributes to the destruction of particles about the barrier in the form of the walls of the chamber and the baffle element.

 The drawing shows a diagram of a longitudinal section of a grinding chamber.

 The grinding chamber includes a housing 1, two grinding sections 2, each of which is placed in one plane along the rotor, including the disk 3, equipped with accelerating vanes 4. Each rotor includes a shaft equipped with a rotational drive (not shown), allowing the rotors to rotate towards each other . In the housing cover of the grinding chamber, coaxial to the axis of rotation of the rotors are loading holes 5 and 6, made in the form of nozzles for connection to the loading nozzles. The grinding sections of the chamber are connected by a tangential channel 7, the side walls of which 8 and 9 are made spiral with respect to the corresponding grinding section. In the center of the tangential channel, discharge openings 10 and 11 are made opposite each other for connection with discharge nozzles. The hole 10 is provided with a conical sleeve 12 immersed in the channel.

 Jet rotary grinding chamber operates as follows.

 Raw materials from the material supply system are simultaneously fed into two sections of the grinding chamber through the loading holes 5 and 6 to the center of the rotating disks 3. Next, particles of the crushed material through the interscapular space between the accelerating blades 4 of the grinding sections, in which the necessary acceleration is obtained, move inside the spiral of the tangential channel 7 towards each other, where they collide with each other by the walls of the channel 8 and 9, as well as the sleeve 12, immersed in the channel. In the center of the tangential channel, the material being crushed falls into an aerodynamic vortex, which separates the crushed particles by weight into two streams. A stream of lighter small particles fills the inner space of the sleeve and through the outlet 10 enters the discharge pipe. A stream of heavier coarse particles enters through aperture 11 into another discharge port.

 Using the inventive jet-rotor grinding chamber for grinding allows you to adjust the range of grinding, since fractionation occurs already inside the grinding chamber.

Claims (2)

 1. Grinding chamber, comprising a housing with two grinding sections communicating with each other by a tangential channel in which a baffle element is located, rotors with accelerating blades mounted on disks placed in each section, loading holes in the upper case cover and an unloading hole in the lower cover housing in the center of the tangential channel, characterized in that the feed holes are made in the form of nozzles and are located coaxially with the corresponding rotor, in the center of the tangential channel coaxially with the discharge from A hole in the bottom cover of the housing contains an additional discharge opening in the upper cover of the housing, inside of which there is a sleeve, which is made in the form of a truncated cone immersed in a tangential channel with a smaller diameter, at least 0.10 of its depth, while the disk, one ends of the accelerating blades are located on the outer perimeter of the disk, and the other ends form an inner circle whose radius is not less than the radius of the loading hole, and the distance between the ends of the blades along the perimeter is at least twice as large as the distance between the ends of the blades forming the inner circle.  2. The grinding chamber according to claim 1, characterized in that the blades are made in the form of long and short rectangles that alternate with each other, while one end of both blades is located on the outer perimeter of the disk, and the radius of the circle described by the other end of the short the blades, is at least half the radius of the circle described by the other end of the long blades.