Abstract
A screw bolt for connecting a lower casing part of a turbine and an upper casing part of a turbine, has a bolt body with a lower end and an upper end, an external thread being arranged on both the lower end and the upper end. A casing for a turbine has a lower casing part, an upper casing part, a screw bolt and two attachment nuts screwed onto ends of the screw bolt, wherein the upper casing part has an upper receiving section and the lower casing part has a lower receiving section of a continuous screw bolt receiving portion for receiving the screw bolt. A turbine has such a casing and a method for assembling such a casing of a turbine.
Claims
1. A screw bolt for connecting a lower casing part of a turbine and an upper casing part of a turbine, comprising: a bolt body with a lower end and an upper end, wherein in each case one external thread is arranged on the lower end and on the upper end, and a support device for support on the lower casing part is arranged on the bolt body between the lower end and the upper end.
2. The screw bolt as claimed in claim 1, wherein the support device is arranged in circumferentially encircling fashion on the bolt body.
3. The screw bolt as claimed in claim 1, wherein the support device is designed to engage into a support receptacle of the lower casing part.
4. The screw bolt as claimed in claim 1, wherein the support device has a rotation-preventing section, wherein the rotation-preventing section is designed to make contact, in form-fitting fashion, with at least one rotation-preventing region in one of the two casing parts.
5. The screw bolt as claimed in claim 1, wherein the bolt body has an opening which extends in continuous fashion between the lower end and the upper end.
6. A casing for a turbine, comprising: a lower casing part, an upper casing part, a screw bolt and two fixing nuts screwed onto ends of the screw bolt, wherein the upper casing part has an upper receptacle section and the lower casing part has a lower receptacle section of a continuous screw bolt receptacle for receiving the screw bolt, wherein the screw bolt has a support device, wherein the support device is supported on the lower casing part.
7. The casing as claimed in claim 6, wherein the screw bolt comprises a bolt body with a lower end and an upper end, wherein in each case one external thread is arranged on the lower end and on the upper end, and wherein the support device for support on the lower casing part is arranged on the bolt body between the lower end and the upper end.
8. The casing as claimed in claim 6, wherein the lower casing part has a support receptacle, wherein the support receptacle at least partially receives the support device of the screw bolt.
9. The casing as claimed in claim 6, wherein the support device has a rotation-preventing section and at least one of the two casing parts has a rotation-preventing region, wherein the rotation-preventing section is designed to make contact, in form-fitting fashion, with the rotation-preventing region.
10. The casing as claimed in claim 9, wherein the rotation-preventing region is formed as part of the support receptacle.
11. The casing as claimed in claim 6, wherein at least one of the fixing nuts is in the form of a capped nut.
12. A turbine, comprising: a casing, wherein the casing is designed as claimed in claim 6.
13. A method for assembling a casing of a turbine, wherein the casing is as claimed in claim 6 the method comprising: a) inserting a screw bolt into an end position in a lower receptacle section of a screw bolt receptacle in the lower casing part, wherein, in the end position, a support device of the screw bolt is supported on the lower casing part, b) attaching a fixing nut to a lower end of the screw bolt, c) mounting an upper casing part onto the lower casing part, wherein, in the process, the screw bolt is inserted into an upper receptacle section of the screw bolt receptacle in the upper casing part, and d) attaching a fixing nut to an upper end of the screw bolt.
14. The method as claimed in claim 13, wherein the screw bolt is heated before step d).
15. The method as claimed in claim 14, wherein a length of the screw bolt is measured before the heating and after step d).
16. The screw bolt as claimed in claim 4, wherein the at least one rotation-preventing region in one of the two casing parts, is the support receptacle of the lower casing part.
17. The method of claim 14, wherein the screw bolt is inductively heated before step d).
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0033] The present invention will be described below on the basis of the appended drawings, in which, schematically in each case:
[0034] FIG. 1 shows a screw bolt according to the invention,
[0035] FIG. 2 shows a lower casing part with an inserted screw bolt according to the invention, and
[0036] FIG. 3 shows a sectional drawing of a casing according to the invention of a turbine.
DETAILED DESCRIPTION OF INVENTION
[0037] Elements of identical function and mode of operation are denoted in each case by the same reference designations in FIGS. 1, 2 and 3.
[0038] FIG. 1 shows a screw bolt 10 according to the invention. A screw bolt 10 according to the invention has, in particular, a bolt body 11. The bolt body 11 has in each case one external thread 14 on a lower end 12 and on an upper end 13. In particular, a fixing nut 22 (not shown) can be screwed onto said external threads 14. In particular, a screw bolt 10 according to the invention has a support device 17. In the illustrated embodiment of a screw bolt 10 according to the invention, said support device 17 is arranged in the middle between the two ends 12, 13 of the screw bolt 10. The bolt body 11 of the screw bolt 10 is of substantially cylindrical form, wherein a radial extent of the screw bolt 10 is increased by way of the support device 17. In particular, it is thereby possible for a screw bolt 10 to be supported on a lower casing part 20 (not shown) by way of a form fit of the support device 17 with the lower casing part 30 when the screw bolt 10 is inserted into a receptacle of the lower casing part 30. The screw bolt 10 is thus reliably prevented from falling through the receptacle in the lower casing part 30. In particular, the illustrated support device 17 is of circumferentially encircling form, whereby tilting of the screw bolt 10 in the receptacle of the lower casing part 30 can also be prevented. Furthermore, in the embodiment shown, the screw bolt 10 according to the invention has rotation-preventing sections 18 on its support device 17. Said rotation-preventing sections 18 are in this case in particular designed such that, as shown, the support device 17 is not radially symmetrical. In particular by way of a form fit with a rotation-preventing region 33 in a casing part 30, 40 (not shown), it is thus possible for the screw bolt 10 to be reliably prevented from rotating, in particular during the attachment of fixing nuts 22 (not shown) to the external threads 14. There is thus no need for additional fixing or holding of the screw bolt 10, for example by way of an additional tool. Furthermore, the screw bolt 10 has an opening 15 which extends in continuous fashion in particular between the two ends 12, 13 of the screw bolt 10. For example, measurement tools for measuring a length of the screw bolt, or a heating device, may be inserted into such an opening 15. By measuring the length of the screw bolt, it can be ensured that the screw bolt has, even after the assembly of the casing 20 (not shown), a length which is ideal for the casing 20. By heating the screw bolt 10, it is furthermore possible to realize greater strength in the attachment of fixing nuts 22. Heating causes the screw bolt 10 to expand. Then, during the assembly of the casing, fixing nuts 22 are screwed onto the external thread 14, in particular so as to bear in form-fitting fashion against the casing 20. After the screw bolt 10 cools, it contracts again, whereby particularly good fixing of the fixing nuts 22 on the casing 20 can be realized. Assembly of a casing 20, in particular of an inner casing, of a turbine 50 (not shown) can thereby be simplified.
[0039] FIG. 2 shows a screw bolt 10 according to the invention which is arranged in a receptacle in a lower casing part 30. This corresponds to the state, during the assembly of a casing 20 (not shown), after the step a) of a method according to the invention. Here, the screw bolt 10 is situated in its end position 16. The upper end 13 with the external thread 14 projects out of the lower casing part 30, with the opening 15 in the screw bolt 10 also being accessible. The illustrated lower casing part 30 has, in particular, a support receptacle 32. The support device 17 is in particular positioned in said support receptacle 32, wherein the support device 17 also does not project beyond the support receptacle 32. Attachment of an upper casing part 40 (not shown) to the surface of the lower casing part 30 is thus possible without parts of the screw bolt 10 becoming clamped between the casing parts 30, 40. Furthermore, the support device 17 forms an axial partial form fit with the support receptacle 32, whereby the screw bolt 10 is prevented from advancing further from its end position 16 into the lower casing part 30. Furthermore, the support device 17 has a rotation-preventing section 18 which likewise forms a form fit with a rotation-preventing region 33 of the support receptacle 32. Rotation of the screw bolt 10 is thus reliably prevented. When fixing nuts 22 (not shown) are attached for example to the upper end 13 of the screw bolt 10, there is thus no need for an additional tool to prevent the screw bolt 10 from also turning. This, too, simplifies the assembly of a casing 20 (not shown).
[0040] FIG. 3 shows a sectional illustration of a casing 20 of a turbine 50. The casing 20 in this case has a lower casing part 30 and an upper casing part 40. The two casing parts 30, 40 form a continuously extending screw bolt receptacle 21 which is divided into a lower receptacle section 31 in the lower casing part 30 and an upper receptacle section 41 in the upper casing part 40. A screw bolt 10 according to the invention is inserted into said continuously extending screw bolt receptacle 21. It is possible to clearly see that the lower end 12 and the upper end 13, each equipped with external threads 14, project out of the respective casing part 30, 40. Here, fixing nuts 22 in the form of capped nuts 23 are arranged on the external threads 14. It is also possible to clearly see the small radial space requirement of such capped nuts 23. The screw bolt 10 is in its end position 16. Here, in a manner which is essential to the invention, the screw bolt 10 has a support device 17. Said support device 17, by way of an axial partial form fit with the lower casing part 30, prevents the screw bolt 10 from falling through when the screw bolt 10 is inserted into the continuously extending screw bolt receptacle 21. In particular, in the embodiment shown, there is provided in the lower casing part 30 a support receptacle 32 into which the support device 17 engages. In the embodiment illustrated, the support receptacle 32 is furthermore designed to completely receive the support device 17. The two casing parts 30, 40 can thus bear flat against one another, whereby particularly good sealing of the casing 20 can be achieved. Furthermore, in the embodiment shown, there is provided on the support device 17 a rotation-preventing section 18 which is designed to form a form fit with a rotation-preventing region 33 of the support receptacle 32. Said form fit can reliably prevent rotation of the screw bolt 10, whereby, in particular, attachment of the fixing nuts 22 to the external thread 14 on the lower end 12 and on the upper end 13 of the screw bolt 10 is possible more easily. Additional fixing of the screw bolt 10 to prevent it from rotating, for example by way of an external tool, can thereby be avoided. Furthermore, the screw bolt 10 has a central opening 15 which extends in continuous fashion through the screw bolt 10 from the lower end 12 to the upper end 13. Here, it is for example possible, firstly, for a measurement instrument, for example for measuring the length of the screw bolt, to be inserted into such an opening 15. In this way, it can be established whether the screw bolt has a length ideal for the operation of the turbine 50 and/or for example for the sealing action of the casing 20. Furthermore, a heating device, in particular an induction heating device, for heating the screw bolt 10 may be inserted into the opening 15. This has advantages for example in the attachment and retroactive fixing of the fixing nuts 22. When heated, the screw bolt 10 expands in particular along its longitudinal extent. Fixing nuts 22 are then screwed onto the still-hot screw bolt 10, in particular until they come to bear against the respective casing part 30, 40. As it cools, the screw bolt 10 contracts again, whereby the fixing nuts 22 are pressed against the respective casing part 30, 40. Particularly good fixing of the two casing parts 30, 40 to form a casing 20 of a turbine 50 can thereby be achieved.
