Seal arrangement of a rotary kiln

Abstract

The invention relates to a seal arrangement of a rotary kiln for sealing to a rotary tube having a first and a second seal half (10, 20) and a first and a second traction system (3, 4), wherein the two seal halves (10, 20) apply a traction force (F) by means of the two traction systems (3, 4) for sealing to the outer circumference of the rotary tube.

Description

[0001] Sealing arrangement of a rotary kiln

[0002] Description

[0003] The present invention relates to a sealing arrangement of a rotary kiln, which seals an outer circumference of a rotating part of the rotary kiln, and to a rotary kiln with a sealing arrangement according to the invention.

[0004] Rotary kilns are used extensively in the process industry, for example, in the chemical or cement industries. This presents the problem of sealing a rotating kiln from the environment. For this purpose, a sealing arrangement is located on the outer circumference of the kiln. To ensure trouble-free operation of the kiln, the sealing arrangements must meet the highest standards. However, this makes the sealing arrangements relatively complex and expensive.

[0005] It is therefore an object of the present invention to provide a sealing arrangement of a rotary kiln and a rotary kiln which, with a simple structure and simple, cost-effective manufacture, enables safe operation of the rotary kiln over a long operating period.

[0006] This object is achieved by a sealing arrangement of a rotary kiln having the features of claim 1 and a rotary kiln having the features of claim 13. The subclaims each show preferred developments of the invention.

[0007] The sealing arrangement according to the invention for a rotary kiln for sealing a rotating component of the rotary kiln, in particular a rotary tube with the features of claim 1, has the advantage that its construction is very simple and therefore cost-effective. Furthermore, it is possible to use identical parts, whereby the costs for manufacturing the sealing arrangement can be further reduced. Nevertheless, a secure seal on a rotating part of the rotary kiln can be ensured and thus a loss of energy and product to the atmosphere can be avoided. A further major advantage of the sealing arrangement according to the invention is that relative movements in both the radial and the axial direction can be absorbed. This can occur during operation of the rotary kiln due to thermal influences. This is achieved according to the invention in that the sealing arrangement has a first and a second sealing half.The first seal half comprises a first sealing cord and a first retaining structure with first and second lateral retaining ring elements, wherein a retaining ring element is arranged on each axial side of the first sealing cord. The second seal half comprises a second sealing cord and a second retaining structure with first and second lateral retaining ring elements, wherein the second sealing cord is arranged between the two retaining ring elements. Furthermore, a first and a second tension system are provided. The first tension system is designed to pretension the first seal half onto the rotating component by means of a tensile force F. The second tension system is designed to pretension the second seal half onto the rotating component by means of a tensile force F. The tensile forces of the first and second tension systems are preferably equal.Furthermore, the first and second sealing halves of the sealing arrangement are offset in the axial direction such that a first and second axial overlap region are formed. The first and second sealing cords are guided next to one another at the overlap regions. To ensure sealing in the axial direction at the overlap region as well, the sealing arrangement further comprises a first and a second fixing element, which fixes the first and second sealing halves at the overlap regions in the axial direction.

[0008] Thus, the sealing arrangement on a rotary kiln provides a radial seal on the outer circumference of the rotary kiln and an additional axial seal at the two overlapping areas. This allows the rotary kiln, which rotates during operation of the rotary kiln, to be securely sealed against stationary components of the rotary kiln. The first and second sealing cords wrap around the outer circumference of the rotary kiln, with each sealing cord preferably sealing a sealing area on the rotary kiln of 180° in the radial direction. Furthermore, the first and second tension systems are preferably of identical design. This enables a reduction in the complexity of the sealing arrangement by using a large number of identical parts.

[0009] Preferably, the overlapping areas of the two seal halves are opposite each other.

[0010] More preferably, the sealing arrangement further comprises contact sealing rings arranged axially between the sealing cords and the support structures. The contact sealing rings are thus in direct contact with the sealing cords. The contact sealing rings are preferably metallic, in particular made of bronze, brass, or PTFE. The contact sealing rings are preferably arranged such that the sealing cords protrude slightly beyond the contact sealing rings in the radially inward direction. Thus, the outer circumference of the rotary kiln is sealed by the contact between the rotary kiln and the sealing cords. Should wear occur on the sealing cords, the contact sealing rings also come into contact with the outer circumference of the rotary kiln.In this case, the sealing cords can now be replaced, or alternatively, the rotary kiln can continue to operate, causing the contact sealing rings, which are now in contact with the outer circumference of the rotary kiln together with the sealing cords, to wear out. After a certain period of operation, both the sealing cords and the contact sealing rings must be replaced.

[0011] The contact sealing rings are preferably firmly connected to the sealing cords, for example by pins which are passed through the sealing cords.

[0012] To ensure the simplest possible design, the contact sealing rings are preferably constructed from a plurality of ring segments. The ring segments are preferably of identical construction and preferably have an arcuate projection at one end in the circumferential direction and an arcuate recess formed corresponding to the arcuate projection at the other end.

[0013] Preferably, the tension systems each have a fixed bearing at one end of the sealing cords and a tensioning device at the other end. This allows for a particularly simple and cost-effective design. Alternatively, the tension systems each have tensioning devices at both ends of the sealing cords.

[0014] The tension devices preferably each comprise a compression spring, e.g., a cylindrical spring or disc spring, which is configured to exert the tensile force F on the sealing cords. The compression spring is preferably arranged between a stationary support and a nut connected to a tension rod. The tension rod preferably has a thread so that the preload can be adjusted by turning the nut on the threaded rod, which is connected to a sealing cord.

[0015] To enable the simplest possible fixation at the overlapping areas, the first and second fixing elements each comprise two plates that are detachably connected to one another. The plates can be connected to one another, for example, by screws or similar means. The plates are particularly preferably part of a housing of the sealing arrangement.

[0016] To better accommodate axial movements of the rotary tube, the sealing arrangement preferably further comprises preloading elements that exert a preload on the first and second sealing halves in the axial direction. Furthermore, support elements are preferably arranged on the outer circumference of the first and second sealing cords, preventing relative movement between the two sealing cords and the contact elements. The support elements are preferably pins, which are preferably fixed to the retaining ring elements of the support structures. Thus, the sealing cords and the contact elements jointly follow radial movements of the pressure tube if the pressure tube performs such radial movements during operation.

[0017] The sealing arrangement preferably further comprises support arms on which the tension systems are arranged. The support arms are preferably part of a housing of the sealing arrangement.

[0018] To measure wear on the sealing arrangement, the two tension systems preferably have wear indicators. These wear indicators can, for example, be measuring scales located on the tension rod of the tension systems.

[0019] Furthermore, the present invention relates to a rotary kiln with a rotary tube and a sealing arrangement according to the invention.

[0020] Preferred embodiments of the invention are described in detail below with reference to the accompanying drawings. In the drawing:

[0021] Fig. 1 is a schematic plan view in the axial direction of a sealing arrangement on a rotary tube of a rotary kiln,

[0022] Fig. 2 is a perspective view of the sealing arrangement of Fig. 1,

[0023] Fig. 3 is a perspective, enlarged partial view of the sealing arrangement of Fig. 1,

[0024] Fig. 4 is a schematic representation of sealing cords of the sealing arrangement of Fig. 1 ,

[0025] Fig. 5 is a schematic, perspective partial view of the sealing arrangement of Fig.

[0026] 1 ,

[0027] Fig. 6 is a schematic perspective view of part of the

[0028] Sealing arrangement of Fig. 1,

[0029] Fig. 7 a schematic representation of the function of the traction systems of the

[0030] Sealing arrangement of Fig. 1 , and

[0031] Fig. 8 is a schematic representation of the tension systems of an alternative sealing arrangement.

[0032] A sealing arrangement 1 according to a preferred embodiment of the invention is described in detail below with reference to Figures 1 to 7. The sealing arrangement 1 is arranged on an outer circumference of a rotating rotary tube 101 of a rotary kiln 100. Arrow A symbolizes a rotation of the rotary tube 101.

[0033] The sealing arrangement 1 is fixed in position and does not rotate with the rotary tube 101.

[0034] The sealing arrangement 1 for sealing the rotary tube 101 comprises a first sealing half 10 and a second sealing half 20. The two sealing halves 10, 20 are essentially identical in design. The two sealing halves are point-mirrored at a center point M of the sealing arrangement. A central axis XX runs through the center point M in the axial direction of the sealing arrangement.

[0035] The first sealing half 10 comprises a first sealing cord 11 and a first retaining structure 12. The first retaining structure 12 comprises a first retaining ring element 13 and a second retaining ring element 14.

[0036] The second seal half 20 is constructed in the same way as the first seal half 10 and comprises a second sealing cord 21 and a second retaining structure 22. The second retaining structure 22 also comprises a first and second retaining ring element 23, 24. One retaining ring element 23, 24 is arranged on each axial side of the second sealing cord 21.

[0037] The sealing arrangement 1 further comprises a first tension system 3 and a second tension system 4. The two tension systems 3, 4 are configured to exert a tensile force F on the first and second sealing cords 11, 21. Thus, the two tension systems 3, 4 pretension the two sealing cords 11, 21 radially onto the rotary tube 101 to provide a sealing effect on the outer circumference of the rotary tube. This sealing effect is present both when the rotary tube 101 is stationary and when it is rotating.

[0038] Furthermore, the first and second sealing halves 10, 20 are arranged offset in the axial direction of the sealing arrangement such that a first overlap region 5 and a second overlap region 6 are formed. The offset arrangement of the two sealing cords 11, 21 thus enables, on the one hand, a radial seal on the inner circumference of the sealing cords on the rotary tube and, at the two overlap regions, an axial seal between the two sealing cords 11, 21. This is illustrated in particular in Fig. 2 by way of example at the first overlap region 5, where the first and second sealing cords 11, 21 run a short distance apart.

[0039] In order to ensure the axial sealing at the two overlapping regions 5, 6, the sealing arrangement further comprises a first fixing element 901 at the first overlapping region 5 and a second fixing element 902 at the second overlapping region 6. The two fixing elements 901, 902 fix the two sealing halves 10, 20 and are U-shaped in section, so that the first and second sealing cords are held in the axial direction.

[0040] The first support structure 12 and the second support structure 22 thus form an annular frame, with the sealing cords 11, 21 arranged between the support ring elements 13, 14 and 23, 24. The support ring elements can preferably be part of a housing 9.

[0041] The fixing elements 901, 902 can also be part of the housing 9 of the sealing arrangement 1.

[0042] The sealing arrangement 1 further comprises a first and second contact sealing ring 7, 8 on each sealing half 10, 20. As can be seen particularly from Figures 3, 4, and 5, a contact sealing ring 7, 8 is arranged on each axial side of the sealing cords 11, 21. The contact sealing rings 7, 8 are formed from a plurality of ring segments 70, 80.

[0043] The ring segments 70, 80 are shown in detail in Fig. 4 and have an arcuate projection at one end and an arcuate recess corresponding to the arcuate projection at the opposite end. This allows for a close arrangement of the ring segments.

[0044] As can be seen in particular from Fig. 5, the sealing cords 11 and 21 protrude slightly radially inward from the contact sealing rings 7, 8 by a dimension B. This ensures that in the assembled (new) state, the sealing cords 11, 21 rest against the outer circumference of the rotary tube 101.

[0045] To prevent relative movement between the first and second sealing cords 11, 21 and the contact sealing rings 7, 8 in the radial direction, a plurality of support elements 51 in the form of small pins are provided. The pins are preferably arranged between the first and second contact sealing rings 7, 8 (see Fig. 5).

[0046] Furthermore, a plurality of axial preloading elements 50 are provided along the circumference, which exert an axial force on the outer contact sealing rings.

[0047] During operation of the rotary kiln, the sealing cords 11, 21 first come into direct sealing contact with the outer circumference of the rotary kiln. If, after a certain period of time, wear occurs on the inner surfaces of the sealing cords 11, 21, the edge regions of the first and second contact sealing rings 7, 8 of the two sealing halves 10, 20 also come into contact with the outer circumference of the rotary kiln. A user of the sealing arrangement according to the invention can then decide whether to replace only the sealing cords 11, 21 or to continue operating the rotary kiln, so that wear also occurs on the inner edges of the first and second contact sealing rings 7, 8. If the rotary kiln continues to be operated, in addition to the sealing on the inner circumference of the sealing cords 11, 21, a further seal is also formed on the edges of the first and second contact sealing rings 7, 8.

[0048] As the rotary kiln continues to operate, the inner surfaces of the sealing cords 11, 21 and the inner edges of the contact sealing rings 7, 8 wear together. Once a certain degree of wear is reached, the sealing cords and the contact sealing rings must be replaced together.

[0049] As can be seen from the schematic representation of Fig. 7, the sealing arrangement 1 of this exemplary embodiment comprises two tension systems 3, 4. The first tension system 3 comprises a tension device 31 and a fixed bearing 30, between which the first sealing cord 11 runs. The second tension system 4 comprises a fixed bearing 40 and a tension device 41, between which the second sealing cord 21 runs. Thus, each tension system 3, 4 comprises a fixed bearing and a tension device.

[0050] The first and second pulling devices 31, 41 have the same structure. In detail, Fig. 6 shows the second pulling device 41, which has a compression spring 42 arranged around a pull rod 43, a nut 44 and a stationary support 45. A bore for the pull rod 43 to pass through is formed in the support 45. The pull rod also has a thread onto which the nut 44 is adjustably screwed. By adjusting the position of the nut, the pretensioning force of the pulling device 41 can be adjusted. Since the compression spring is arranged between the stationary support 45 and the nut 44, it can be designed as a compression spring.

[0051] Preferably, a wear indicator 15, for example a scale (not shown in detail), is also arranged on the pulling device, with which wear of the sealing arrangement can be indicated, since in the event of wear on the components in contact with the rotary tube, the position of the pull rod 43 changes due to the compression spring 42.

[0052] The first traction device 31, which is arranged diametrically opposite the second traction device 41 (see Figures 1 and 2), is constructed identically to the second traction device 41. The first traction device 31 comprises a compression spring 32, a threaded pull rod 33, a nut 34 screwed onto the thread, and a stationary support 35.

[0053] A connecting piece 36 (see Figures 4 and 5) is provided for connecting the first tensioning device 31 and the first sealing cord 11. Similarly, a connecting piece 46 is also provided between the second tensioning device 41 and the second sealing cord 21 (see Figures 4 and 5).

[0054] As can be seen schematically in Fig. 5, four through-openings 90 are provided in the annular housing 9 for guiding the respective ends of the sealing cords 11, 21 out of the housing to the outside in the direction of support arms 93. The support arms 93 are arranged on the outside of the housing 9 and serve to fasten the first and second pulling devices 31, 41. The fixed bearings 30, 40 of the pulling systems 3, 4 are arranged on the other two support arms 93.

[0055] Fig. 8 shows an alternative embodiment of the invention, in which the tension systems 3, 4 each have additional tension devices instead of the fixed bearings. Thus, the first tension system 3 comprises two tension devices 31 at each end of the sealing cord 11, and the second tension system 4 comprises two tension devices 41 at the end of the second sealing cord 21 (see Fig. 8).

[0056] However, as a comparison of Figures 7 and 8 shows, the sealing principles are the same in both alternative embodiments if an additional pulling device is arranged instead of the fixed bearing.

[0057] Thus, the sealing arrangement 1 according to the invention can enable secure sealing on a rotating rotary tube 101 of a rotary kiln 100. In principle, sealing can also be achieved in both directions of rotation of the rotary tube 101 without resulting in additional leaks or the like. The performance of the seal is the same in both directions of rotation. To stiffen the sealing arrangement, several cross struts or flanges or the like can be provided on the housing. In the event of wear, only the sealing cords 11, 21 and, if applicable, the contact sealing rings 7, 8 need to be replaced in the sealing arrangement according to the invention. The tension systems 3, 4 and the other components of the sealing arrangement 1 can be reused.

[0058] The axially offset arrangement of the first and second sealing cords 11, 21 also enables radial sealing around the entire circumference of the rotary tube. At the two transition regions 5, 6, an additional axial seal is provided, which is maintained by the first and second fixing elements 901, 902. Furthermore, wear of the sealing arrangement can easily be read off the tension systems 3, 4 located outside the housing, for example, on a scale. In addition to the above written description of the invention, explicit reference is hereby made to the drawings of the invention in Figs. 1 to 8 for the purpose of supplementing its disclosure.

[0059] List of reference symbols

[0060] I Sealing arrangement

[0061] 3 first train system

[0062] 4 second train system

[0063] 5 first overlap area

[0064] 6 second overlap area

[0065] 7 first contact sealing ring

[0066] 8 second contact sealing ring

[0067] 9 housings

[0068] 10 first seal half

[0069] II first sealing cord

[0070] 12 first support structure

[0071] 13 first retaining ring element

[0072] 14 second retaining ring element

[0073] 15 Wear indicator

[0074] 20 second seal half

[0075] 21 second sealing cord

[0076] 22 second support structure

[0077] 23 first retaining ring elements

[0078] 24 second retaining ring element

[0079] 30 fixed bearings

[0080] 31 first pulling device

[0081] 32 compression spring

[0082] 33 Drawbar

[0083] 34 Mother

[0084] 35 Support

[0085] 36 connecting piece

[0086] 40 fixed bearings

[0087] 41 second pulling device

[0088] 42 compression spring

[0089] 43 Drawbar

[0090] 44 Mother

[0091] 45 Support

[0092] 46 connecting piece

[0093] 50 axial preload elements

[0094] 51 support elements / pins

[0095] 70 ring segments 80 ring segments

[0096] 90 passage opening

[0097] 91 first record

[0098] 92 second plate 93 support arm

[0099] 100 rotary kilns

[0100] 101 rotating rotary kiln

[0101] 901 first fixing element

[0102] 902 second fixing element A direction of rotation

[0103] B Distance between the edge of the contact sealing rings 7, 8 and the inner circumference of the sealing cords

[0104] F traction force

[0105] M center

[0106] central axis

Claims

Claims 1. Sealing arrangement of a rotary kiln for sealing at a rotating rotary tube, comprising - a first sealing half (10) with a first sealing cord (11) and a first retaining structure (12), wherein the first retaining structure (12) comprises a first retaining ring element (13) and a second retaining ring element (14) and wherein a retaining ring element (13, 14) is arranged on an axial side of the first sealing cord (11), - a second sealing half (20) with a second sealing cord (21) and a second retaining structure (22), wherein the second retaining structure (22) has a first lateral retaining ring element (23) and a second lateral retaining ring element (24) and wherein a retaining ring element (23, 24) is arranged on an axial side of the second sealing cord (21), - a first tension system (3) which is set up to pre-tension the first sealing half (10) onto the pressure pipe by means of a tensile force (F) for sealing on an outer circumference of the pressure pipe, - a second tension system (4) which is designed to pre-tension the second sealing half (20) against the outer circumference of the pressure tube by means of a tensile force (F), - wherein the first sealing half (10) and the second sealing half (20) are arranged axially offset from each other such that a first overlap area (5) and a second overlap area (6) are formed on the circumference of the sealing arrangement, wherein the first and second sealing cords (11, 21) run side by side on the first and second overlap areas (5, 6), and - a first fixing element (901) at the first overlap area (5), which fixes the areas of the first and second sealing cord (11 , 21) located at the first overlap area (5) in the axial direction and a second fixing element (902) at the second overlap area (6), which fixes the areas of the first and second sealing cord (11 , 21) located at the second overlap area in the axial direction.

2. Sealing arrangement according to claim 1, further comprising contact sealing rings (7, 8) which are arranged axially between the sealing cords (11, 21) and the retaining structures (12, 22).

3. Sealing arrangement according to claim 2, wherein each contact sealing ring (7, 8) is composed of a plurality of ring segments (70, 80).

4. Sealing arrangement according to one of the preceding claims, wherein the first and second tensioning systems (3, 4) each have a fixed bearing (30, 40) at a first end of the sealing cords (11, 21) and a tensioning device (31, 41) at the other second end of the sealing cords (11, 21), or - wherein the tension systems (3, 4) have tension devices (31, 41) at both ends of the sealing cords (11, 21).

5. Sealing arrangement according to claim 4, wherein the tension devices (31 , 41) each have a compression spring (32, 42) which is configured to exert the tensile force (F) on the sealing cords (11 , 21).

6. Sealing arrangement according to claim 5, wherein the pulling device (31, 41) further comprises a threaded pull rod (33, 43), a nut (34, 44) and a stationary support (35, 45), wherein the compression spring (32, 42) is arranged around the pull rod (33, 43) and is located between the nut (34, 44) and the support (35, 45).

7. Sealing arrangement according to one of the preceding claims, wherein the first and second fixing element (901 , 902) each comprise a first plate (91) and a second plate (92) which are detachably connected to each other.

8. Sealing arrangement according to claim 7, wherein the first and second fixing element (901 , 902) is part of an annular housing (9) of the sealing arrangement.

9. Sealing arrangement according to one of the preceding claims, further comprising pretensioning elements (50) which are arranged to exert a pretension in the axial direction on the sealing cords (11 , 21).

10. Sealing arrangement according to one of the preceding claims, further comprising support elements (51) which are arranged on the outer circumference of the first sealing cord (11) and the second sealing cord (21) to prevent a relative movement between the sealing cords (11 , 21) and the contact sealing rings (7, 8).

11. Sealing arrangement according to claim 10, wherein the support elements (51) are pins which are fixed between the contact sealing rings (7, 8).

12. Sealing arrangement according to one of the preceding claims, further comprising support arms (93) on which the tension systems (3, 4) are arranged. Sealing arrangement according to one of the preceding claims, wherein the tension systems (3, 4) have wear indicators for indicating wear sealing cords (11, 21). Rotary kiln (100) with a rotary tube (101) and a sealing arrangement (1) according to one of the preceding claims, which seals on an outer circumference of the rotary tube (101).

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