DE20019276U1 - Rotary drum with rolling element arrangement - Google Patents

Description

KUNIG ■ PALGEN · SCHUMACHER •-•K-liLIIN··· *··*

DÜSSELDORF · FOOD

PATENT ATTORNEYS

our reference: 100 221 Il HS/mb essen, 10 November 2000

VEBA OEL Technology and Automation GmbH

Johannastr 2 - 8 D - 45899 Gelsenkirchen

Rotating drum with rolling element arrangement

The invention relates to a rotary drum with a rolling element arrangement according to the preamble of claim 1.

Such rotary drums are primarily used for chemical processes that take place at elevated temperatures, such as carbonization processes, whereby operating temperatures inside the rotary drum, which is usually heated externally, can be in the range of between 600 ⁰ C and 850 ⁰ C and of course also higher or lower. For the constant cleaning of the rotary drum interior from caking, encrustations or the like, so-called rolling elements are used, which roll along the inside of the rotary drum shell due to the rotary drum rotation and, with their external cleaning strips or the like, completely or partially remove the caking or encrustations on the rotary drum wall or prevent them from forming extensively at all.

In the rotary drum with internal cleaning by rolling elements known from WO 9839611, it is provided that the non-cylindrical and cylindrical inner wall areas typical for the feed end of a rotary drum

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by a combination of rolling elements with cleaning surfaces arranged at an angle to one another, preferably by several rolling elements coupled one behind the other, each of which is equipped with a ball joint on its input-side end to allow rolling movement. Practical tests have shown that such ball joints do not have a satisfactory service life.

Based on this, the invention is based on the object of ensuring low-maintenance operation of the cleaning devices in rotary drums of the generic type and, in particular, of improving the service life of the motion bearings for the cleaning bodies.

To solve this problem, a rotary drum with the features of claim 1 is proposed. The invention is based on the knowledge that a separation of axially and radially loaded bearing surface areas significantly improves the mobility of rolling and/or scraping cleaning bodies.

In order to achieve the desired low-maintenance condition of the cleaning body bearing for chemical processes carried out in rotating drums that take place at elevated temperatures, such as the carbonization of various feedstocks such as oil residues, tar pitch, chemical and other waste materials and residues, it is proposed that the linings inserted between the axial and radial bearing surfaces be made of self-lubricating, high-temperature-resistant and/or corrosion-resistant material.

The invention achieves a significantly improved mobility of the cleaning bodies and thus a better cleaning effect as well as a significantly increased service life of the cleaning body bearings - even at high temperatures, such as those that occur during carbonization in rotating drums, e.g. between 600 ⁰ C and 850 ⁰ C. In addition to graphite as a bearing coating,

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In particular, metal-impregnated graphite bearings, special graphite bearings or ceramic bearings come into consideration, as specified in particular in claim 2. The swivel and rotary bearings according to the invention can be designed so that sliding speeds of up to about 10 m/s and specific surface loads of up to about 3 N/mm ² can be accommodated, whereby an excellent rotating, sliding and/or swivel or pendulum movement of the cleaning bodies is permanently guaranteed. The consistent separation of rotary and swivel bearings is of particular advantage. The invention can also handle process temperatures of up to 1150 ⁰ C.

The aforementioned components to be used according to the invention, as well as those claimed and described in the embodiments, are not subject to any special exceptional conditions in terms of their size, shape, choice of material and technical conception, so that the selection criteria known in the field of application can be applied without restriction.

Further details, features and advantages of the subject matter of the invention emerge from the subclaims and from the following description of the associated drawing, in which - by way of example - a preferred embodiment of the rotary drum according to the invention with cleaning bodies is shown.

In the drawing show:

Fig. 1 a rotary drum in longitudinal section;

Fig. 2 for the rotary drum 2 according to Fig. 1 a combined rolling element and scraping element arrangement in a view from above in three working positions (0°, 10° and 20°) - in detail;

Fig. 3 the scraping device according to Fig. 1 and Fig. 2 in perspective - in a simplified representation;

Fig. 4 of the rolling element/scraping element combination according to Figures 1 to 3, an enlarged detailed view in axial section - broken away;

Fig. 5 of the scraping device according to Figures 1 and 2, a detailed representation of a universal joint in axial section through one of the two bearing journals and
10

Fig. 6 of the rolling element/scraper body combination according to Fig. 1 an enlarged detailed view of the fastening device in axial section - broken open.

Fig. 1 shows a rotary drum 10 for chemical processes at elevated temperatures, such as carbonization processes, with a cylindrical rotary drum region 1OA and a conical rotary drum region 1OB at the input-side front end.

A rolling element arrangement 12 for cleaning the interior of the drum consists of a slightly conical rolling element 12A with external cleaning elements 12B. The fixed front entry end 14 of the rotary drum 10 has a fastening device 16 which is connected to the entry end 14 in a rotationally fixed manner and serves to hold the rolling element arrangement 12 at a distance from the entry end 14. The rolling of the rolling element 12A along the inner circumference S of the rotary drum 10 rotating about its longitudinal axis, i.e. on the rotary drum wall 10C, is made possible by a rotary bearing 18 which is connected at one end to the fastening device 16 and at the other end to the rolling element arrangement 12.

An elongated scraping device 20 is interposed between the fastening device 16 and the pivot bearing 18. This consists of the

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The embodiment shown and in this respect preferred comprises a cylindrical scraping body 20A with two scraping strips 20B, 20C distributed asymmetrically over the circumference and aligned essentially parallel to the scraping body. The scraping device 20 is attached to the fastening device 16 in a pendulum-like manner but not rotatable about itself. A first universal joint 22A with offset cross heads is used for this pivot bearing, which is described in more detail below in connection with Fig. 5. At its end on the pivot bearing side, the scraping device 20 is connected to the pivot bearing 18 in a pendulum-like manner in at least one direction.

A universal joint 22B comparable to the universal joint 22A is used for this purpose. These two universal joints each ensure a pivoting connection of the scraping device 20 with the fastening device 16 or the pivot bearing 18 in the horizontal and vertical direction in the manner of a cardan joint. This makes it possible for the rolling element arrangement 12 to be carried along a little in the direction of rotation when the rotary drum is rotating due to friction between the rolling element 12A and the inner rotary drum wall 10C and then to move in a rolling manner in the direction of the rotary drum base against the rotary drum movement due to the gradient towards the rotary drum base. However, this movement is only rarely axially parallel to the rotary drum - and not only because of the one-sided connection of the rolling element to the input end 14; Because the rolling element 12A is designed to be slightly conically widened towards the input end, its input-side end runs in the opposite direction to the direction of rotation of the rotary drum 10 and its other end runs in the same direction (by being dragged along). Because the rolling element is easily carried along by the rotary drum, the input-side rolling element end with the pivot bearing 18 arranged there moves laterally in the opposite direction to the direction of rotation of the rotary drum with respect to its rest position in the drum base.

Because of this migration, the rolling element-side end of the scraping device 20 and the universal joint 22B arranged therein carry out a potentially quite considerable pivoting movement with respect to the

supporting end 14 and the fastening device 16. By using the two universal joints, the scraping body 2OA and the scraping strips 2OB and 2OC carry out a pure pivoting movement along the inner wall surface of the conical rotary drum area 10B, ie without rotating about the longitudinal axis of the scraping body 2OA. These relationships are shown in Fig. 2 by straight and circular directional arrows 24A and 24B. In this illustration, in addition to the O ⁰ -, the 10° and 20° positions of the scraping device 20 and the rolling element arrangement 12 are also shown in relation to the extended rest position (O° position) in the rotary drum base.

In order to best separate the pendulum or swivel movement of the scraping device 20 from the rolling movement of the rolling element arrangement 12, the pivot bearing 18 consists of a cantilever pin 26, which has axial bearing surfaces 26A and radial bearing surfaces 26B. For this purpose, the cantilever pin 26 is cylindrical and has a circumferential flange-like collar 26C in a central area with flat circular ring surfaces on both sides. The cantilever pin 26 is surrounded by a bearing cage 28, which in turn has axial bearing surfaces 28A and radial bearing surfaces 28B corresponding to the bearing surfaces 26A and 26B of the cantilever pin 26. Simple assembly of the bearing cage and cantilever pin is ensured by a segmented design of the bearing cage and connecting screws 30 for the cage segments.

In order to ensure that the rotary bearing can be maintained for a sufficiently long period even at the high working temperatures typical for many carbonization processes, high-temperature-resistant and self-lubricating linings 32A and 32B are inserted between the interacting bearing surfaces 26A/28A and 26B/28B. They therefore preferably have the shape of ring disks or pipe sections. However, they can also be provided in segment form, in particular with a mutual distance between the bearing surfaces on both sides. Bushings 34 and

Fitting pieces 36 make it possible to compensate for dimensional tolerances of the pads in relation to the bearing surfaces.

The cantilever pin 26, which can be screwed directly centrally into the end wall 12C of the rolling element arrangement 12 in a rotationally fixed manner, is preferably surrounded and supported by a frame or, particularly preferably and as shown in the drawing in Fig. 4, by a housing 38. This also surrounds the bearing cage 28 and protects the pivot bearing 18 from contamination via labyrinth seals 38A. At the free end of the cantilever pin 26, the housing-like pivot bearing cage 28 is closed and directly connected to the universal joint 22B.

The two universal joints 22A and 22B are constructed in the same way as shown in Fig. 5 for one universal joint half: The pivot pins 4OA and 4OB, which are orthogonal to one another and connected to one another, protrude on both sides from their connecting arm 4OC in an aligned arrangement. They form cylindrical radial bearing surfaces on their outer circumference, which are surrounded by linings 42 made of self-lubricating, high-temperature-resistant material in a similar way to the radial bearings of the pivot bearing 18. Housing caps 44 and bushings 46 promote a precise assembly and long maintenance-free operating periods of the pivot bearings (universal joints 22A and 22B).

8 List of reference symbols

10 Rotating drum 10A cylindrical rotating drum area 10B conical rotary drum area 10C Rotary drum inner wall 12 Rolling element arrangement 12A cylindrical rolling element 12B Cleaning element 12C Front wall 14 End of entry 16 Fastening device 18 Pivot bearing 20 Cockroach device 2OA Scraper body 2OB Scraper bar 2OC Scraper bar 22A universal joint 22B universal joint 24A Direction arrow 24B Direction arrow 26 Cantilever tenon 26A axial bearing surfaces 26B radial bearing surfaces 26C Federation 28 Bearing cage 28A axial bearing surfaces 28B radial bearing surfaces 30 Connecting screws 32A Coverings 32B Coverings 34
a Cans a

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·· · Fitting • * ·· *· •♦ ·
" · 4»· · · · Housing • > . .. . Labyrinth seal * * · «· « Pivot pin 9 36 Pivot pin 38 Connecting arm 38A Coverings 4OA Housing caps 4OB Cans 4OC 42 44 46

Claims (5)

1. Rotary drum ( 10 ) for chemical processes at elevated temperatures, such as carbonisation processes, a) with a rolling element arrangement ( 12 ) for cleaning the drum interior b) with a fixed frontal entry end ( 14 ) for material to be treated, c) with a fastening device ( 16 ) for the rolling element arrangement ( 12 ) at the entry end ( 14 ) of the rotary drum ( 10 ) and d) with a rotary bearing ( 18 ) allowing the rolling element ( 12A ) to roll on the inside of the rotary drum wall ( 10C ) and connecting the fastening device ( 16 ) and the rolling element ( 12A ), characterized ,
that the pivot bearing ( 18 ) and any existing pivot bearings, such as universal joints ( 22A ; 22B ), have linings ( 32A ; 32B ; 42 ) made of self-lubricating, high-temperature-resistant and/or corrosion-resistant material, which are inserted between annular disk-shaped and/or cylindrical, interacting bearing surfaces (26A; 28A; 26B; 28B; 40A/B; 44) of the pivot bearing ( 18 ) and any existing pivot bearing: 2. Rotary drum according to claim 1, characterized in that the coatings ( 32 A; 32 B; 42 ) consist of pure graphite, of carbon-impregnated graphite, of metal-impregnated graphite (such as with antimony, copper, bronze, nickel, silver, etc.) or of ceramic, such as silicon carbide, etc. 3. Rotary drum according to claim 1 or 2, characterized in that the rotary bearing ( 18 ) has a cantilever pin ( 26 ) with axial and radial bearing surfaces ( 26 A; 26 B) and a bearing cage ( 28 ) surrounding the cantilever pin ( 26 ) with corresponding axial and radial bearing surfaces ( 28 A, 28 B) for the cantilever pin ( 26 ). 4. Rotary drum according to claim 3, characterized in that the cantilever pin ( 26 ) is carried by a frame or housing ( 38 ) surrounding the cantilever pin and the bearing cage ( 28 ). 5. Rotary drum according to one of claims 1 to 4, characterized in that the rotary bearing ( 18 ) is assigned at least one pivot bearing designed as a universal joint ( 22 A; 22 B).