DE19627319C2 - Ring armor for a rotating pneumatic dust conveyor, especially a coal dust fan mill - Google Patents

Description

According to the preamble of claim 1, the invention relates to a ring armor for a rotating pneumatic Dust conveyor, in particular a coal dust fan mill.

The ring armor provides wear protection between the rotation system and Housing of a rotating dust conveyor. In the case of coal dust fan mill is the ring armor between the grinding chamber housing the front derwand and the rotating impact wheel on a ring armor mount arranges.

After a relatively short period of operation there is wear on the ring armor and the grinding chamber door armor through the abrasive parts of the to be processed Fuel, so that replacements and / or wear repairs are required become necessary.

To reduce wear, it is known to protect the solid material from the Arrange ring armor or the ring armor with a special Wear material to be provided (DE 42 33 614 C2). A major improvement However, wear behavior was not achieved, although considerable Expenses are required.

After extensive and time-consuming investigations, it was found that due to the peripheral speed of the beating wheel the coal dust fan mill a pressure difference between the rotating beater wheel Grinding chamber and grinding chamber door is built. Because of this pressure difference is caused by the ring gap between the impact wheel and the armor a solid cross flow to the grinding chamber door and a solid Ring flow formed in the annular gap.

The wear troughs on the grinding chamber are caused by the cross flow armored armor and through the ring flow the wear recesses in the Ring armor formed.

Furthermore, in the publication DD 284 345 A7 there is a corner armor for a coal Dust fan mill known. A corner armor should be used in the event of wear, the air gap between the peripheral housing and beater wheel is guaranteed.  The corner armor consists of a solid, wedge-shaped body that Has flanks, the flanks with a groove forming the flank part is provided. Through this one groove, a cross-sectional widening and thus the abrasive speed on the corner armor is reduced.

The disadvantage here is that if the depth of the groove is too great, it will accumulate Abrasive material comes and the ring armor on the groove base ver very quickly wears. If, on the other hand, the groove depth is chosen too small, the desired impact occurs effect on. Disadvantageously, this also applies if the groove length is too large ge an. Another disadvantage is that if the groove is too small there was a so-called gap bridging and therefore no effect of the desired impact effect.

Advantageously, however, in the solution according to the invention by special arrangement of the elevations on the ring armor wear contoured. This special V shape causes the abrasive material to is deflected towards the sides and thus the wear rate growing wear reduces itself, which leads to a considerable service life leads increase.

Furthermore, a ring armor is in the document DE 295 19 446 U1 Impact wheel mills are known, the ring armor composed of segments is set, which are attached to the front wall of the grinding chamber.

The disadvantage here is that because of the use of ceramic work a wear-resistant ring armor is available from the Grinding chamber door can be released quickly, but the pressure difference that arises by the beater wheel rotating at a constant speed between the Grinding chamber housing and the collapse of coal is built, leads to an ab rapid current.

A negative aspect of this solution according to the invention is that the acceleration of the Abrasive current and thus the wear that occurs as a result is not reduced becomes.

The invention has for its object the cross and ring flow and to significantly reduce the associated solids transport.

This is achieved in that according to the invention the ring armor with transverse grooves provided for the direction of rotation of the rotation system is provided.

By the invention, the wear of the ring and Armouring of the milling chamber door is significantly reduced because the cross and ring currents due to the higher current that has occurred with the arrangement of the grooves mung resistance is also significantly reduced.

Based on an embodiment, the invention he he below to be refined. It shows:

Fig. 1: The arrangement of ring and grinding chamber door armor in a schematic representation at the coal dust fan mill

Fig. 2: The schematic representation of the unwound ring armor element in side view and top view

At the grinding chamber housing 1 of the coal dust fan mill, the grinding chamber armor 2 and the ring armor receptacle 3 and the ring armor 4 are arranged ( FIG. 1).

The grinding chamber door 5 has the grinding chamber armor 6 and is connected to the grinding chamber housing via the sealing system 7 . In the Mahlkammerge housing 1 , the impact wheel 8 is arranged. The annular gap 12 is formed between the ring armor 4 and the impact wheel 8 . The ring armor 4 consists of individual ring armor elements 9 ( Fig. 2), these taking on the Ringpanzerauf 3 are fixed. The ring armor elements 9 have the grooves 10 and elevations 11 arranged transversely to the conveying direction of the dust-air mixture. To increase the flow resistance in the annular gap 12 , the grooves 10 and elevations 11 are arranged with a uniform and / or uneven conditions. The depth and width of the grooves is len depending on the annular gap, ie from the distance of the ring armor 4 from the impact wheel 8 .

The following design is intended for a coal dust fan mill with a peripheral impeller speed of 80 m / s:
Depth of the grooves = distance (annular gap)
Width of the grooves = at least 5 times the distance

The mode of action is as follows:

Due to the depth and width of grooves 10 arranged the lateral and annular flow due to flow resistance "torn" and within the reefs 10 small swirl is formed. The reduced flows lead to the reduction in wear of the ring armor 4 and the grinding chamber door 6 due to the substantially reduced solids transport in the annular gap. 6 As a result, the service life of the ring armor 4 and the grinding chamber door armor 6 is increased despite the use of steel of the RST quality. This makes it possible to stretch the rhythm of wear repairs and thus reduce costs.

List of the reference symbols used

1

Grinding chamber housing

2nd

Grinding chamber armor

3rd

Ring armor receptacle

4

Ring armor

5

Grinding chamber door

6

Armouring for the milling chamber

7

Sealing system

8th

Impact wheel

9

Ring armor elements

10th

groove

11

increase

12th

Annular gap

Claims (4)

1. Ring armor for a rotating pneumatic dust conveyor, in particular a coal dust fan mill, the ring armor being arranged in the gap between the rotation system and the housing of the dust conveyor, characterized in that the ring armor is provided with grooves introduced transversely to the direction of rotation of the rotation system. 2. Ring armor according to claim 1, characterized in that the grooves with an even and / or uneven division are arranged. 3. Ring armor according to claim 1 and 2, characterized in that the Depth and width of the grooves depending on the distance of the ring armor are formed by the rotation system. 4. ring armor according to claim 3, characterized in that the grooves with a depth equal to the distance and with a width at least equal to that 5 times the distance are formed.