STUD SYSTEM FOR CONNECTING FLANGES

Abstract

Provided is a stud system for connecting a first flange to a second flange of a tower, the flanges including arrangements of openings in the first flange corresponding to arrangements of threaded blind openings in the second flange, with a predefined opening-length and a predefined opening-diameter of the openings in the first flange and a predefined non-threaded length and a predefined threaded length of the threaded blind openings in the second flange, the stud system including: a stud bolt with a head end, a threaded end and an intermediate portion, and a spacer tube partly encompassing the stud bolt with an outer diameter bigger than the predefined opening-diameter, wherein the stud bolt includes stopping means at the head end, preventing the spacer tube from slipping over the head end. The spacer tube) constructed such that it can be removed laterally from the stud bolt.

Claims

1. A stud system for connecting a first flange to a second flange of a tower, the first flange comprising annular arrangements of openings corresponding to annular arrangements of threaded blind openings in the second flange, with a predefined opening-length and a predefined opening-diameter of the openings in the first flange and a predefined non-threaded length and a predefined threaded length of the threaded blind openings in the second flange, the stud system comprising: a stud bolt with a head end, a threaded end, and an intermediate portion between the head end) and the threaded end; and a spacer tube partly encompassing the stud bolt with an outer diameter bigger than the predefined opening-diameter; wherein the stud bolt comprises a stopping means at the head end, preventing the spacer tube from slipping over the head end; wherein the spacer tube is constructed such that the spacer tube can be removed laterally from the stud bolt.

2. The stud system according to claim 1, wherein the head end is threaded and the stud bolt comprises a nut on the threaded head end as the stopping means, further wherein the stud bolt comprises a washer arranged around the stud bolt between the nut and the spacer tube; and/or the stud bolt comprises a bolt extender arranged around the stud bolt at a far side of the spacer tube seen from the nut; and/or the stud bolt comprises an extender-washer which is a combination of a washer and a bolt extender arranged around the stud bolt at the far side of the spacer tube seen from the nut.

3. The stud system according to claim 2, wherein the nut is arranged such that a remaining connecting-length between the nut or the washer, and a tip of the threaded end is shorter than the predefined opening-length plus the predefined non-threaded length, Further wherein a thread of the head end is designed such that the nut can be turned in order to increase the connecting length.

4. The stud system according to claim 1, wherein the spacer tube is formed by at least two spacer segments including a first spacer segment and a second spacer segment, arranged adjacent to another, further wherein the first spacer segment and the second spacer segment are movably connected with each other, such that after removing the first spacer segment the first spacer segment still clings to the second spacer segment, further wherein a connection is achieved by connection loops made of wire or string.

5. The stud system according to claim 1, wherein a length of the spacer tube is such that when arranged at the stopping means a remaining length of the intermediate portion that is not covered by the spacer tube together with a length of the threaded end is shorter than the predefined opening-length.

6. The stud system according to claim 1, wherein the spacer tube is made from metal, cardboard, wood , or a dense polymer of polyethylene or polyprophylene.

7. The stud system according to claim 1, wherein the spacer tube has a cylindrical shape with part of a circumference removed, creating an open C-section, wherein a width of the opening is less than a diameter of the intermediate portion of the stud bolt so that the spacer tube does not fall from the stud bolt , but can be removed by pulling sideways from the stud bolt, further wherein the width of the opening is bigger than 90% of a diameter of the intermediate portion.

8. A flange with an annular arrangement of openings, the flange comprising a plurality of stud systems according to claim 1 arranged in the openings.

9. A method of assembling a tower comprising tower sections, each equipped with a flange on each face, the flange comprising annular arrangements of threaded blind openings, the method comprising: arranging a tower section on top of a further tower section so that annular arrangements of openings of the flange accord to each other to receive a set of fasteners for connecting the flange; arranging a number of stud systems in a corresponding number of openings of the flange from above prior or after the arrangement of the tower segments; removing of a number of spacer tubes from the stud bolt of at least one arranged stud system so that the stud bolt is able to fall in the corresponding opening; and forming a permanent connection between the tower section and the further tower section by the stud bolts.

10. The method according to claim 9, wherein the number of stud systems are arranged in a corresponding number of openings of the flange, the method further comprising: after removing of the number of spacer tubes, increasing the connecting length of the stud bolt by turning a nut along the threaded part of the head end until the connecting length is longer than the predefined opening-length plus the predefined non-threaded length.

11. The method according to claim 9, wherein the number of stud systems are arranged in a corresponding number of openings of a flange, the method further comprising: after removing a first spacer segment from a stud bolt and falling of the stud bolt in the corresponding opening, removing a second spacer segment from the stud bolt to bring the stud bolt in connection with a thread of the opening.

12. The method according to claim 11, wherein the first spacer segment and the second spacer segment are movably connected with each other and the removing procedure of the first spacer segment is performed such that the removed first spacer segment still clings to the non-removed second spacer segment.

13. The method according to claim 9, wherein the openings of the flange are inclined relative to a vertical direction by at least 5° and less than 45°, and wherein the number of stud systems are arranged in a corresponding number of the openings of the flange from above.

14. The method according to claim 9, wherein the spacer tubes of the number of stud systems comprise connection loops, wherein the connection loops are connected with another by a connection element, wherein the spacer tubes are removed by moving the connection element such that the spacer tubes are laterally removed from the respective stud bolts, further wherein the connection element is flexible.

15. A tower comprising a plurality of essentially cylindrical tower sections equipped with flanges and permanently connected by stud bolts inserted through inclined openings of the flanges by the method according to claim 9.

Description

BRIEF DESCRIPTION

[0045] Some of the embodiments will be described in detail, with references to the following Figures, wherein like designations denote like members, wherein:

[0046] FIG. 1 shows a cross section of a flange connection with a stud bolt according to the prior art;

[0047] FIG. 2 shows a perspective view on a preferred stud system according to embodiments of the invention;

[0048] FIG. 3 shows a perspective view on a flange equipped with stud systems according to the invention;

[0049] FIG. 4 shows a cross section of a flange connection with a preferred stud system according to the invention;

[0050] FIG. 5 shows the procedure of forming a flange connection with a stud system according to FIG. 4;

[0051] FIG. 6 shows a cross section of a flange connection with a preferred stud system according to the invention;

[0052] FIG. 7 shows the procedure of forming a flange connection with a stud system according to FIG. 6;

[0053] FIG. 8 shows a cross section of a flange connection with a preferred stud system according to the invention;

[0054] FIG. 9 shows the procedure of forming a flange connection with a stud system according to FIG. 8;

[0055] FIG. 10 shows a perspective view on a spacer tube comprising two spacer segments; and

[0056] FIG. 11 shows a tower comprising stacked tower sections connected by flanges according to the invention.

DETAILED DESCRIPTION

[0057] FIG. 1 shows a cross section of a flange connection with a stud bolt 2 according to the prior art. Each flange has a primary bolt circle comprising an annular arrangement of inclined openings 1_thru, 1_part to receive a set of fasteners (the stud bolts 2) for connecting the flange 1 to the complementary flange 1. An inclined opening 1_thru, 1_part of the primary bolt circle is characterized by the angle of inclination θ subtended between its longitudinal axis (dash dotted line) and a surface normal N of the flange connection face. The flange 1 also comprises a body section (L-part) with a secondary bolt circle comprising an annular arrangement of openings (vertical hole at the right side of the flange) to receive a set of fasteners for connecting the flange 1 to an interim structure or to the complementary flange 1.

[0058] The stud bolt 2 can theoretically be divided into three parts: the head end 2a, that is threaded here and provided with a nut 2b, the threaded end 2d, with which the stud bolt 2 is screwed into the thread of the threaded blind opening 1_part, and an intermediate portion 2c that may be (partly) threaded or (partly) a shank. The length of the hole in the upper flange segment is predefined and the predefined “opening-length” LO. The length of the non-threaded part of the blind opening 1_part in the lower flange 1 is the predefined non-threaded length LN, and the length of the threaded part of the blind opening 1_part in the lower flange 1 is the predefined threaded length LT. Both openings 1_thru, 1_part have a predefined opening diameter OD at least concerning the non-threaded part.

[0059] FIG. 2 shows a perspective view on a preferred stud system 4 according to embodiments of the invention. It comprises a stud bolt 2 like shown in FIG. 1 and a spacer tube 3. In difference to the stud bolt 2 of FIG. 1, the preferred stud bolt 2 shown here additionally comprises a washer 2e and an bolt extender 2f.

[0060] The stud system is arranged in an opening 1_thru of a flange 1. This is possible because of the spacer tube 3 that prevents the stud bolt 2 from falling into the opening 1_thru, but only sticking in it with a fraction of its length (see e.g., FIG. 4). The spacer tube 3 partly encompasses the stud bolt 2 with an outer diameter bigger than the predefined opening-diameter OD (see FIG. 1) and is prevented from slipping over the head end 2a of the stud bolt 2 by the nut 2b acting as stopping means 2b. The spacer tube 3 is constructed such that it can be removed laterally from the stud bolt 2 due to a slit that can be seen over the whole length of the spacer tube 3.

[0061] FIG. 3 shows a perspective view on a flange 1 equipped with stud systems 4 according to embodiments of the invention. The stud systems are mainly the same as shown in FIG. 2 with the differences that the bolt extender 2f is arranged between flange 1 and spacer tube 3 and that the spacer tubes comprise filament loops 3c as connection loops 3c, wherein the filament loops 3c of all spacer tubes 3 are connected with each other by a rope serving as connection element 2d. By pulling this rope, the spacer tubes 3 could be quickly removed from the stud bolts 2 of the stud system 4.

[0062] FIG. 4 shows a cross section of a flange connection with a preferred stud system 4 according to embodiments of the invention, similar to the stud system 4 shown in FIG. 2 (only without a bolt extender 2f). It can be seen that the spacer tube 3 prevents the tip of the stud bolt 2 from protruding out of the bottom of the flange 1. The distance between the washer 2e and the tip of the threaded end 2d is the connecting-length LC. This is the length with that the stud bolt would extend into the opening 1_thru, 1_part if there were no spacer tube 3.

[0063] FIG. 5 shows the procedure of forming a flange connection with a stud system 4 according to FIG. 4.

[0064] In the left picture A, the flanges 1 are arranged upon another. Since the stud system 4 does not protrude from the bottom of the upper flange, an easy adjustment is possible.

[0065] In the next picture B, the spacer tube 3 is removed and the stud bolt glides down in the opening 1_thru, 1_part of the flange.

[0066] In the next picture C, the threaded end 2d of the stud bolt 2 hits the thread of the blind opening 1_part.

[0067] Now, in picture D, the stud bolt 2 can be screwed into the thread and the nut 2b can be fastened to connect the flanges 1 with each other.

[0068] FIG. 6 shows a cross section of a flange connection with a stud system 4 according to embodiments of the invention. This stud system 4 is similar to the stud system shown in FIG. 4 with the difference that the spacer tube 3 is segmented into a first spacer segment 3a and a second spacer segment 3b. These two spacer segments 3a, 3b can be removed separately from the stud bolt 2.

[0069] FIG. 7 shows the procedure of forming a flange connection with a stud system 4 according to FIG. 6.

[0070] In the left picture A, the flanges 1 are arranged upon another and the first spacer tube 3a is removed. The stud bolt glides down in the opening 1_thru, 1_part of the flange, but stops shortly before the thread of the blind opening 1_part due to the second spacer segment. Thus, the thread is not damaged by the impact of the movement of the stud bolt 2.

[0071] In the next picture B, the second spacer tube 3b is removed. Since the tip of the stud bolt 2 is not far from the thread of the blind opening 1_part, the stud bolt 2 touches the thread of the blind opening 1_part very smoothly without damaging the thread.

[0072] Now, in picture C, the stud bolt 2 can be screwed into the thread and the nut 2b can be fastened to connect the flanges 1 with each other.

[0073] FIG. 8 shows a cross section of a flange connection with a stud system 4 according to embodiments of the invention. This stud system 4 is similar to the stud system shown in FIG. 4 with the difference that the nut 2b has been positioned nearer to the threaded end 2d. The head end 2a is threaded so that the nut 2b can be screwed up and down the head end 2a.

[0074] FIG. 9 shows the procedure of forming a flange connection with a stud system 4 according to FIG. 8.

[0075] In the left picture A, the flanges 1 are arranged upon another. Since the stud system 4 does not protrude from the bottom of the upper flange, an easy adjustment is possible.

[0076] In the next picture B, the spacer tube 3 is removed and the stud bolt glides down in the opening 1_thru, 1_part of the flange.

[0077] In the next picture C, the threaded end 2d of the stud bolt 2 does not hit the thread of the blind opening 1_part like in FIG. 5, but stops near the thread of the blind opening 1_part as in FIG. 7. The star at the washer indicates that the impact occurs there. A damage to the surface of the flange may be prevented by positioning the washer 2e under the spacer tube 3 (between spacer tube 3 and flange 1). Also a bolt extender 2f arranged as shown in FIG. 3 may prevent possible damage.

[0078] In picture D, the nut is unscrewed in the direction of the head end 2a so that the tip of the stud bolt 2 smoothly touches the thread of the blind opening 1_part. Now (after unscrewing the nut 2b a little bit more), the stud bolt 2 can be screwed into the thread and the nut 2b can be fastened to connect the flanges 1 with each other.

[0079] FIG. 10 shows a perspective view on a spacer tube 3 that is formed by two spacer segments 3a, 3b, a first spacer segment 3a and a second spacer segment 3b, that are arranged upon another. Here the first spacer segment 3a and the second spacer segment 3b are movably connected with each other by a connection string 3e. For removing the spacer segments 3a, 3b, each spacer segment 3a, 3b comprises a filament loop 3c, especially made of wire or string. Due to the special connection of the spacer segments 3a, 3b, after removing the first spacer segment 3a, it still clings to the second spacer segment 3b. The filament loops 3c are used to connect several spacer segments 3a, 3b with spacer segments 3a, 3b of different stud systems (see e.g., FIG. 3).

[0080] FIG. 11 shows a tower 5, such as a wind turbine tower, comprising tower sections 50 “stacked” on top of each other and connected by flanges 1 according to embodiments of the invention. The flanges are outlined without further details. The way of equipping and fastening the flanges is described more accurately in the preceding figures.

[0081] Although the present invention has been disclosed in the form of preferred embodiments and variations thereon, it will be understood that numerous additional modifications and variations could be made thereto without departing from the scope of the invention.

[0082] For the sake of clarity, it is to be understood that the use of “a” or “an” throughout this application does not exclude a plurality, and “comprising” does not exclude other steps or elements.