RU8637U1 - Counterflow jet mill - Google Patents

Abstract

1. A counter-current jet mill containing a grinding chamber with outlet pipes, including booster tubes opposite and coaxial to each other, accelerating tubes and a coaxial accelerating tube reflector in the form of two hollow truncated cones, with their truncated vertices facing the booster tubes, characterized the fact that the reflector is equipped with barriers in the form of bushings installed at the ends of the booster tubes with guiding protrusions covering the truncated cones of the reflector with a gap. 2. The mill according to claim 1, characterized in that the outlet pipes are located at the side ends of the grinding chamber.

Description

CL.MKIV02S 19/06 UDC 621.926.88 (088.8)

Propagating Jet Mill

The invention relates to the technique of dry jet grinding of bulk materials and can be used to obtain fine powders in the chemical, construction, paint and varnish and other industries.

Known countercurrent jet mill containing a horizontally arranged cylindrical grinding chamber with oppositely and coaxially mounted booster pipes, a barrier with a Central hole, loading and unloading nozzles 1. The disadvantage of this mill is that it does not provide the return of non-ground particles of material after their collision with an obstacle to the two-phase flow flowing from the booster pipes, which significantly reduces the productivity and efficiency of grinding.

The countercurrent jet mill closest in technical essence to this utility model is also known. It contains a grinding chamber with outlet pipes, which includes accelerating tubes opposite and coaxial to each other, and a reflector coaxial to the accelerating tubes in the form of two hollow truncated cones facing truncated vertices to the booster tubes 2. However, in this jet mill, the energy of the booster gas is not fully used

pipes, which reduces the efficiency and productivity of the grinding process.

The purpose of this utility model is to increase the grinding efficiency.

This goal is achieved by the fact that in a counter-current jet mill containing a grinding chamber with outlet nozzles, which includes accelerating tubes opposite and coaxial to each other in the grinding chamber and a reflector coaxial to the accelerating tubes in the form of two hollow truncated cones facing their truncated vertices to the booster tubes, the reflector is equipped with barriers in the form of bushings installed at the ends of the booster tube with guiding protrusions covering the truncated reflector cones with a gap, with the output nozzles that are located at the lateral ends of the grinding chamber.

The essence of this utility model is illustrated by drawings, which show:

FIG. 1 is a structural diagram of a jet mill;

FIG. 2 - node I of FIG. one;

FIG. 3 is a section AA in FIG. 2.

The jet mill comprises loading devices 1, ejectors 2 with hoppers 3, a grinding chamber 4, on the lateral ends 5 of which accelerating tubes 6 are mounted counter-aligned and coaxial to each other, a reflector 7 including hollow truncated cones 8, joined together by bases 9 and facing their vertices to the booster tubes, and the obstructions 10 installed at the ends of the booster tubes in the form of bushings with protrusions 11, covering truncated cones 8 with a gap 12, the latter being connected to the obstructions 10 by means of pylons 13. The outlet pipes 14 are ground second camera located at the side of its ends and connected by means of conduits 15 or with precipitators (cyclone) 16 of the finished material directly or through the separators 17. The separators 17 are connected by pipelines 18 return unground particles to the desired size

the crushed material with bins 3, and the outlet pipes 19 of the cyclones 16 are connected to the filter 20 for cleaning the exhaust gas.

The booster tubes can also be equipped with secondary ejectors 21 with annular nozzles 22. Ejectors 2 and 21 are connected via pipelines 23 with control valves 24 to the common main 25 of the mill supplying compressed gas (air).

The jet mill operates as follows.

The crushed material from the charging devices 1 is fed into the bunkers 3 of the ejectors 2, accelerated by compressed gas in the accelerating pipes 6 to high speeds and enters the internal cavity of the reflector 7. In the zone 26 inside the hollow cones 8 of the reflector there is a collision of material particles and their partial dissociation. Particles that have slipped through this zone, as well as fragments of material from zone 26, are reflected by the inner surfaces of the cones 8. In this case, large particles fall into the high-speed two-phase stream flowing from the booster pipes and are additionally crushed in it, while smaller ones are carried away by the return stream 27 in the zone its turns are broken, interacting with obstacles 10. Next, the jets of gas with the material are directed by the protrusions 11 along the outer surfaces of the cones 8 and secondarily interact with each other in the zone 28. After this interaction, the flow and drains from the grinding chamber 4 through the nozzles 14.

In the separators 17, larger particles are separated from the stream and returned through pipelines 18 to the hoppers 3 for a second grinding cycle. The powder obtained as a result of grinding is separated from the gas in the precipitators 16 and discharged from their storage bins 29, and the gas enters the filter 20, where fine dust is separated from it. The purified gas leaves the nozzle 30, and the dust is discharged through the nozzle 31.

In this case, the gas coming from the nozzles 22 of the secondary ejectors contributes, on the one hand, to the return of large particles to the main stream flowing from the pipes 6, and to the acceleration of particles in this stream, a, with

on the other hand, the removal of small particles from the reflection and their acceleration along the outer surfaces of the cones 8 into the interaction region 28. The separation of the outlet pipes 14 to the side ends of the chamber 4 contributes to a longer interaction and, accordingly, grinding of material particles in a disturbed gas return flow.

Due to the connection of the cones of the reflector with each other, the supply of the reflector with barriers that cover its truncated cones, as well as the spacing of the outlet pipes to the side ends of the grinding chamber, multiple interaction of particles of the crushed material between themselves and the solid surfaces of the reflector is ensured. As a result, the energy of compressed gas is used more fully and, thereby, the grinding efficiency is increased.

Claims (2)

1. A counter-current jet mill containing a grinding chamber with outlet pipes, including booster tubes opposite and coaxial to each other, accelerating tubes and a coaxial accelerating tube reflector in the form of two hollow truncated cones, with their truncated vertices facing the booster tubes, characterized the fact that the reflector is equipped with barriers in the form of bushings installed at the ends of the booster tubes with guiding protrusions covering the truncated cones of the reflector with a gap. 2. The mill according to claim 1, characterized in that the outlet pipes are located at the side ends of the grinding chamber.