RU2368434C1 - Air-operated centrifugal dynamic classifier - Google Patents

Abstract

FIELD: engines and pumps.

SUBSTANCE: invention relates to construction, chemical and food industries to size various loose materials. Proposed classifier comprises casing with cover, working member consisting of upper and lower plates and blades arranged downstream of the former, starting material feed branch pipe and fine fraction discharge branch pipe. The latter is arranged at the casing top, interacts with aforesaid working member to force fine fraction out by air flow. The classifier includes also coarse fraction discharge branch pipe arranged at the casing bottom and furnished with unloading device and working member drive. Note that it comprises additionally the device to eliminate parasitic parallel air flow representing multiple orifices made in the casing cover and arranged all around the fine fraction discharge branch pipe.

EFFECT: higher efficiency, reduced power consumption.

3 dwg

Description

The invention relates to mechanical engineering, namely to air centrifugal classifiers with a rotating working body, and can find application in the construction, chemical, food and other industries for the separation of various bulk materials by size.

Known air centrifugal-dynamic classifier containing a housing with a lid, a working body, consisting of upper and lower disks and blades located between the disks on their peripheral part, a hopper with a pipe for outputting a large fraction, located under the working body and interacting with it, the pipe for supplying the source material, located in the lower part of the housing, a pipe for outputting the fine fraction together with the air flow, located in the upper part of the housing and interacting with the central part of the work about the body, the pipe for the withdrawal of large fractions located in the lower part of the body, and the drive of the working body (SU 183684 A1, B07B 7/083, publ. 09/07/1966).

However, in the known classifier due to the fact that the pressure in the working body is lower than in the body cavity, a parasitic parallel air flow arises in the space between the body cover and the upper disk of the working body, moving from the annular separation zone (the space between the body wall and the working body ) to the Central part of the working body through a constructive annular gap between the upper disk of the working body and the pipe to output the fine fraction together with the air flow. Together with this air flow, part of the large particles moves from the separation zone. In the central part of the working body, large particles are picked up by the air stream and, together with the separated small particles, are removed from the classifier. This circumstance reduces the efficiency of classification of the source material by size.

Also known is an air centrifugal-dynamic classifier containing a housing with a cover, a working body consisting of upper and lower disks, vanes located between disks on their peripheral part, and vanes located on the peripheral part of the upper disk as a means to prevent the occurrence of parasitic parallel air flow, a pipe for supplying the source material located in the lower part of the housing, a pipe for outputting the fine fraction along with the air flow located in the upper hour and the housing and cooperating with the central part of the working organ pipe for the withdrawal of the coarse fraction at the bottom of the hull, and drive the working member. When the working body rotates, the blades located on the upper disk create an air flow directed towards the classification zone (SU 806162 A1, B07B 7/083, publ. 23.02.1981).

However, in this classifier, the blades located on the upper disk of the working body increase the aerodynamic resistance of the working body, which leads to an increase in energy costs associated with preventing the occurrence of parasitic parallel air flow.

The objective of the invention is to reduce energy costs associated with preventing the occurrence of spurious parallel air flow by reducing the aerodynamic drag of the working body.

The essence of the invention lies in the fact that to solve the problem by the specified technical result, an air centrifugal-dynamic classifier containing a housing with a cover, means to prevent the occurrence of spurious parallel air flow, a working body consisting of upper and lower disks and vanes located between the disks on their peripheral part, a pipe for supplying the source material, a pipe for outputting the fine fraction together with the air flow located in the upper part to housing and interacting with the Central part of the working body, the nozzle for outputting a large fraction, equipped with a discharge device and located in the lower part of the housing, and the drive of the working body, characterized in that as a means to eliminate spurious parallel air flow, the classifier contains holes made in the lid housing around the nozzle to output the fine fraction along with the air flow.

The invention is illustrated by drawings: figure 1 - General view of the classifier, the vertical axial section; figure 2 - a view of figure 1; figure 3 - increase in figure 1.

Air centrifugal-dynamic classifier contains a housing 1 (for example, cylindrical) with a cover 2 made with holes 3, a working body consisting of an upper disk 4, a lower disk 5 and blades 6 located between the disks 4 and 5 on their peripheral part, tangential a pipe 7 for supplying source material located in the upper part of the housing 1, a pipe 8 for outputting a fine fraction together with the air flow located in the upper part of the housing 1 and interacting with the central part of the working body, the pipe 9 for the output of a large fraction, equipped with a discharge device 10, for example, such as a "flasher", and located in the lower part of the housing 1, and the drive of the working body (not shown).

A pipe 8 for outputting a fine fraction together with the air flow through a cyclone or through a filter system is connected to a fan (not shown in the drawings).

A pipe 7 for supplying the source material can be located in the lower part of the housing 1. A pipe 8 for outputting a fine fraction together with the air flow can be located in the lower part of the housing 1 and interact with the central part of the working body through the lower disk 5. In this case, the cover 2 sec holes 3 is located under the working body. The drive of the working body can be located in the upper part of the housing 1 (not shown in the drawings).

The invention is used as follows.

By means of a drive, the working body is rotated at the required speed. By means of a fan at the outlet of the nozzle 8 for outputting the fine fraction together with the air flow and in the central part of the working body, a vacuum is created and through the tangential pipe 7 the source material is fed into the annular separation zone - the space between the wall of the housing 1 and the blades 6 of the working body. In the separation zone, the rotating blades 6 give the air stream containing the source material rotation in a horizontal plane about the vertical axis of the classifier. In this case, two oppositely directed forces act on the material: centrifugal force due to the rotation of the air flow around the vertical axis of the classifier, and aerodynamic drag due to the movement of the air flow through the interscapular space formed by the blades 6 to the central part of the working body.

For large particles in the separation zone, the centrifugal force prevails over the force of aerodynamic drag, as a result of which large particles are thrown onto the wall of the housing 1 and under the influence of gravitational force along it move down and out of the classifier through the pipe 9 by means of a discharge device 10.

For small particles in the classification zone, the aerodynamic drag force prevails over the centrifugal force. As a result of this, they, together with the air flow, move to the central part of the working body and through the pipe 8 together with the air flow are removed from the classifier.

Since there is a vacuum inside the housing 1 and in the working body, atmospheric air enters the classifier through openings 3, which leads to the appearance in the space between the cover 2 and the upper disk 4 of the working body of two air flows directed in opposite directions (figure 3) . One stream is directed to the structural annular gap between the pipe 8 and the upper disk 4. The second stream is directed to the wall of the housing 1, i.e. into the separation zone, which prevents the occurrence of parasitic parallel air flow and the movement of large particles in the central part of the working body.

The boundary of the separation of material is regulated by the number of revolutions of the working body. With an increase in the number of revolutions of the working body, the separation boundary decreases, and vice versa.

Thus, the means for eliminating spurious parallel air flow in the form of holes 3 made in the cover 2 of the housing 1, allows, unlike the blades installed on the upper disk of the working body, to prevent the occurrence of spurious parallel air flow without increasing energy consumption.

Claims (1)

An air centrifugal-dynamic classifier, comprising a housing with a cover, means for eliminating parasitic parallel air flow, a working body consisting of upper and lower disks and blades located between the disks on their peripheral part, a pipe for supplying the source material, a pipe for outputting a fine fraction together with the air flow, located in the upper part of the housing and interacting with the central part of the working body, a pipe for outputting a large fraction, equipped with unloading devices m and located at the bottom of the hull, and drive the working member, characterized in that as a means for eliminating spurious parallel airflow classifier comprises openings formed in the cap body around the nozzle for withdrawal of fine fraction together with the air stream.

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