RU2179068C2 - Jet blower for grinding wet bulk material - Google Patents

Abstract

FIELD: bulk material grinding and drying equipment. SUBSTANCE: jet apparatus has feeding hopper with auger-type dozer, milling chamber connected to divider through pipeline equipped with branch pipe. Divider is connected to milling chamber via pipes and to gas purifying device. Metal rods are welded to outer side of auger-type dozer coil, with metal rods pitch being equal to 0.2-0.5 of auger diameter. Ratio of dozer housing section area and auger section area is 1.3-1.8. Section area of hopper adjoining to dozer may be equal to dozer housing section area. EFFECT: increased efficiency and simplified construction. 2 cl, 3 dwg

Description

 The invention relates to equipment for grinding and drying bulk wet materials and can be used in chemical, metallurgical, concentration, paint and varnish and other industries, where, under the conditions of production, fine grinding and drying of wet material is necessary.

 A known installation for jet grinding bulk materials (AS 365163), containing countercurrent jet mill, classifier, dust separator, dust collector, exhaust fan, hopper and dispenser. In order to automate the workflow and facilitate the supply of sticking-prone source material and coarse fractions returned from the classifier to the booster tubes, the unit is equipped with a hermetic screw distribution device, the receiving hopper of which is connected to the dispenser electric motor with upper and lower level signaling devices.

 The installation does not provide a uniform supply of wet source material to the booster tubes, since prone to sticking material will cover the turns of the screw, reducing its performance. In addition, an additional metering device significantly complicates the design of the installation.

 Known jet mill (a.s. N 562602 from 02.07.75) for dispersing cellulosic materials, including a grinding chamber, two ejectors with pipelines for supplying energy, located on both sides of the grinding chamber, opposing classifiers connected to the grinding chamber by a vertical pipe and loading devices. In order to increase the degree of filling of the energy carrier flow with dispersible material and reduce the specific energy carrier flow, each loading device has a screw, a pipe is placed in its hollow shaft for supplying the energy carrier flow, and an annular channel is formed between the inner surface of the loading device housing and the external surface of the screw shaft, covering the ejector nozzle .

 The design of the described loading device does not solve the problem of uniformly dispensing the dispersible material into the grinding chamber, since the wet material is able to hang on the walls of the hoppers of the loading augers. In addition, the synchronization of the operation of the auger drives for feeding material presents certain difficulties.

The closest in technical essence and the achieved effect to the claimed solution is an inkjet installation for grinding bulk material (patent RU 2079366 from 05.20.97)
The installation includes a grinding chamber with nozzles and pipelines for supplying energy, a separator connected to the chamber by a pipe equipped with a supply pipe for supplying material, a hopper with a dispenser and a device for cleaning gases. At the same time, in order to increase the productivity of the installation, at least one nozzle connected to the pipeline for supplying energy is tangentially cut below the pipe for feeding material into the pipe.

 Installation works as follows. The wet source material from the hopper is dispensed through a feed pipe into a vertical pipe, where it is primary classified and dried in rotating jets of an energy carrier supplied through tangential nozzles. Partially dried material is carried out in a separator, where it is divided into two fractions. The coarse fraction is returned to the grinding chamber to the mantle, and the small fraction is removed from the installation as a finished product.

 When processing a wet material, for example aluminum hydroxide with a moisture content of 15-18%, it freezes in the hopper and “slips” the dispenser elements. As a result, the supply of the starting material to the installation becomes unstable and, as a result, its productivity decreases.

 An object of the invention is to increase the productivity of the installation for jet grinding due to the stabilization of the feed into it of the source material.

 The essence of the technical solution lies in the fact that in a jet installation for grinding and drying loose wet material containing a grinding chamber with nozzles and pipelines for supplying energy, a separator connected to the chamber by a pipe equipped with a supply pipe, a hopper with a screw metering device and a gas purifier , the hopper has vertical walls, while the ratio of the cross-sectional area of the dispenser housing adjacent to the hopper to the cross-sectional area of the screw is 1.3 - 1.8, and and metal rods are welded in increments of 0.2 - 0.5 of the screw diameter. In addition, the cross-sectional area of the hopper adjacent to the dispenser is equal to the cross-sectional area of the dispenser housing.

 In a bunker with vertical walls, the change in volume per unit height is zero, i.e. the wet starting material does not change its packing structure as it moves down to the dispenser and does not hang on the walls as a result of compression in front of the dispenser. In order to prevent “screwing up” of the screw and metal rods welded to its spiral from the outside with wet material, it is installed with some clearance to the dispenser body. Moreover, the ratio of the cross-sectional area of the dispenser body to the cross-sectional area of the screw in the range 1.3 - 1.8 is optimal for filling the annular space of the dispenser with the source material. An increase in this parameter above 1.8 leads to an increase in the power consumption for mixing and loosening a large volume of sediment. Reducing the ratio below 1.3, - to reduce the capacity of the dispenser. The step of arrangement of metal rods welded externally to the screw spiral within 0.2 - 0.5 of the screw diameter is selected for reasons of complete loosening of the sediment layer in the annular space of the batcher and its best transportation to the grinding chamber. At the same time, a decrease in pitch less than 0.2 of the screw diameter leads to an excessive increase in the load on the drive, and an increase of more than 0.5 leads to "slipping" of the internal space of the dispenser housing and deterioration of material transportation.

 The equality of the cross-sectional areas of the hopper at its junction with the dispenser and the cross-sectional area of the dispenser body eliminates the possibility of sediment arches in the hopper and disruption of the material supply to the installation.

In FIG. 1 shows a general view of the installation; in FIG. 2 shows a longitudinal and transverse section of a hopper with a screw feeder; in FIG. 3 is a section along AA in FIG. 2
The installation consists of a receiving hopper 1 with a screw batcher 2. The grinding chamber 3 is connected to the separator 4 by a pipe 5, equipped with a supply pipe 6. The rotor 7 of the separator 4 is rotated by the drive 8. The separator 4 is connected to the grinding chamber 3 by two pipes 9 and device 10 for gas purification. In the grinding chamber 3 is supplied steam CHP through special nozzles directed towards each other. The receiving hopper 1 (Fig. 2) is connected to the housing of the screw feeder 2, along the central axis of the latter there is a screw 11, to the spiral of which metal rods 12 are welded from the outside. The housing of the screw feeder 2 is equipped with a pipe 13 for outputting material.

 Installation works as follows. The wet source material is fed into the hopper 1 (Fig. 2), in which, as the material is dispensed, it is lowered down into the jet unit. In this case, the vertical or slightly inclined walls of the hopper exclude the hanging of the material in it. Further, the material enters the dispenser casing 2, filling the annular gap between the spirals of the screw 11 and the casing of the dispenser 2, where it is mixed with metal rods 12 welded externally to the spiral of the screw 11 in increments of 0.2 - 0.5 from the diameter of the latter. The material mixed in the annular gap does not “lubricate” the screw and is uniformly transported to the pipe 13 and then goes to the pipe 5 through the supply pipe 6. This circumstance makes it possible to stabilize the temperature and energy intensity in the grinding chamber and optimize the operation of the installation.

 The material from the pipe 5 (Fig. 1) is carried upstream of the energy carrier into the separator 4, where, under the action of centrifugal force, it is divided into two fractions. Small particles of material are carried into a gas purification device 10, from where they are ultimately removed as a finished product.

 Large particles are returned through pipes 9 to the grinding chamber 3 for milling.

 The design of the loading device of the installation stabilizes the flow of material into the grinding chamber and allows you to optimize the process parameters.

Claims (2)

 1. An inkjet installation for grinding and drying granular wet material, comprising a grinding chamber with nozzles and pipelines for supplying energy, a separator connected to the grinding chamber by a pipe equipped with a supply pipe, a hopper with a screw metering device and a gas purifier, characterized in that the hopper has vertical walls, while the ratio of the cross-sectional area of the dispenser body adjacent to the hopper to the cross-sectional area of the screw is 1.3-1.8, and metal is welded to the spiral of the screw outside of sul rods in increments of 0.2-0.5 screw diameter.  2. An inkjet installation for grinding and drying granular wet material according to claim 1, characterized in that the cross-sectional area of the hopper adjacent to the dispenser is equal to the cross-sectional area of the dispenser body.

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