CZ292361B6 - Armored ring for rotating pneumatic dust extractor - Google Patents

Abstract

The invented armored ring (6) is made of shaped parts (1) of soft ceramic material and the shaped parts (1) are adapted to the armored ring (6) bearing (2), whereby bottom region of the bearing (2) comprises a removable snap-in part (3).

Description

Technical field

The invention relates to an annular armor for a rotary pneumatic dust conveyor, in particular for a fan coal mill, located in the gap between the rotary system and the housing of the dust conveyor and fixed in a housing provided on the mill housing.

BACKGROUND OF THE INVENTION

The annular armor provides wear protection and is located between the rotary system and the housing of the rotary conveyor for conveying dust and other particulate matter. After a relatively short operating time of 15 hours, the annular armor and also the armor chamber door armor wear off the abrasive particles of the treated solid fuel, so that repairs or replacement of damaged parts are necessary quite often. In addition, inaccurately manufactured annular armor elements, due to their welding with internal bias, cause the weld seams to tear off, causing the elements to fall out.

After extensive and time-consuming tests, it has been found that, due to the peripheral speed of the impeller wheel of the fan coal mill, a pressure differential is created between the grinding chamber and the grinding chamber door area by the rotating impactor. This pressure difference results in a transverse flow of solid particles towards the grinding chamber door and an annular flow of solid particles in the annular gap between the impact wheel and the annular gap occurring in the annular armor. This transverse flow gradually creates crushed depressions in the annular armor.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an annular armor of a fan coal mill 30 that will reduce wear and tear, whose loose annular armor segments would not constitute a source of mill failure, and that would limit transverse and annular flow.

SUMMARY OF THE INVENTION

This object is achieved by an annular armor according to the invention, characterized in that the annular armor is formed from profiled moldings of soft ceramic material and the moldings are adapted to the annular armor receiving, wherein the lower bearing region comprises a removable snap-fit part. Shaped parts and annular armor bearings are provided with a profiled guide.

According to a preferred embodiment of the invention, the annular armor is provided with grooves extending perpendicular to the direction of rotation of the rotation system. The grooves are spaced at uniform and / or 45 non-uniform spacing and have a depth and width formed depending on the spacing of the annular armor from the rotation system. In particular, the grooves are formed with a depth equal to the spacing and a width equal to at least five times the distance of the annular armor from the rotation system.

-1 CZ 292361 B6

Overview of the drawings

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front view of an annular body armor body; FIG. 2 is a schematic cross-sectional view of an annular armor and annular support with a dovetail guide; FIG. Fig. 4 is a schematic illustration of the mutual arrangement of annular armor and armored door of a grinding chamber at a fan coal mill; and Fig. 5 is a schematic side view and plan view of an advanced annular armor element.

DETAILED DESCRIPTION OF THE INVENTION

The grinding chamber housing 7 of the fan coal mill is provided with a grinding chamber opening 8, an annular armor 6, a pressure ring 9. receiving 2 annular armor 25 and a group of annular armor segments 10. The pressure ring 9 for sealing the grinding chamber door 12 and 3. The annular armor segments 10 are formed in the form of profiled shaped parts 1 (FIGS. 2 and 3) and are made of a soft ceramic material. The annular support 2 and the annular armor segments 10 are provided with a dovetail guide 4 (FIG. 2).

The annular support 2 and the molded parts 1 can also be provided with other profiling to form a guide 4 (FIG. 3). The annular armor 6 consists of individual annular armor segments 10.

Armor 11 of the grinding chamber door 35 and housing 2 of the annular armor 6 are formed on the grinding chamber housing 7 of the fan coal mill (FIG. 4).

The grinding chamber door 12 is provided with a door armor 11 and is connected via a sealing system 13 to the grinding chamber housing 7. An impact wheel 14 is disposed in the grinding chamber housing 7, and an annular 40 gap 15 is formed between the annular armor 6 and the impact wheel 14. The annular armor 6 consists of individual annular armor segments (FIG. 5) and is mounted in an annular armor housing 2. The annular armor segments are provided with grooves 5 and elevations 16 extending perpendicular to the conveying direction of the powder / air mixture. To increase the flow resistance in the annular gap 15, the grooves 5 and ridges 16 are spaced at regular and / or non-visible spacing relative to each other. The depths and widths of the grooves 5 should be selected depending on the annular gap 15, i.e. the spacing of the annular armor 6 from the impeller 14. For fan mills for coal milling with an impeller speed of about 80m / s, the following dimensions are proposed:

groove depth = distance (annular gap) groove width = at least five times the distance

-2GB 292361 B6

The effect of annular armor is as follows:

The annular support 2 is welded to the grinding chamber housing 7 and is provided with a guide 4 for the molded part L The guide 4 formed in the annular support 6 is interrupted in the region of the removable snap-fit part 3 or is also formed on the snap-fit part 3 The molding 1 is inserted into the guide 4. When removing the impeller 14 of the fan coal mill, only the lower half of the annular armor segments 10 of the molding 1 is removed by the gap after the snap-in part 3 has been removed and the upper half is locked. The assembly of the impactor 14 proceeds in the reverse order. In the event that the molded parts 1 enter the grinding chamber as a result of wear, they would be ground or ground without interrupting the mill operation, but the molded parts 1 can be replaced by new ones at the next planned mill stop.

Due to the depth and width of the grooves 5 arranged in succession, the transverse and annular flow tears as a result of the continuous flow resistance thus created and small swirls are formed inside the grooves 5. The reduced flows result in a substantially reduced transport of solid particles in the annular gap 15 to reduce wear on the annular armor 6 and the armor door armor 11. As a result, even with the use of GST grade steel, the service life of the annular armor 6 as well as the armor chamber 11 is increased. This can extend the wear cycle of components and reduce operating costs.

The solution according to the invention achieves the following advantages: Prefabrication of the annular armor segments and their low net weight results in a reduction of assembly costs and also in a reduction in the time intervals at which the mill is decommissioned. The molded parts 1 which extend into the interior of the mill are ground and thus no additional mill failures can occur.

Claims (5)

PATENT CLAIMS Annular armor for a rotary pneumatic dust conveying apparatus, in particular for: A fan coal mill located in the gap between the rotation system and the particle conveyor housing and mounted in a housing provided on the mill housing, characterized in that the annular armor (6) is formed from moldings (1) of soft ceramic material and moldings. (1) are adapted to fit (2) annular armor (6), wherein the lower area of the bearing (2) comprises a removable snap-fit part (3). Annular armor according to claim 1, characterized in that the shaped parts (1) and the annular armor (6) support (2) are provided with a profiled guide (4). Annular armor according to claims 1 and 2, characterized in that the annular armor (6) is provided with grooves (5) running perpendicular to the direction of rotation of the rotary system. Annular armor according to claims 1 to 3, characterized in that the grooves (5) are spaced at uniform and / or uneven spacing. Annular armor according to Claims 1 to 4, characterized in that the grooves (5) have a depth and a width formed in dependence on the distance of the annular armor (6) from the rotation system. Annular armor according to claims 1 to 5, characterized in that the grooves (5) are formed with a depth equal to the spacing and a width equal to at least five times the distance of the annular armor (6) from the rotation system.