WO2021077208A1 - System and method for separating a rotor blade from a blade bearing of a wind turbine - Google Patents

Abstract

A system for separating a rotor blade from a rotor hub of a wind turbine has a jacking assembly mountable between a blade root of the rotor blade and a blade bearing of the rotor hub in at least one open unthreaded aperture in the blade bearing and in at least one corresponding open threaded aperture in the blade root. The jacking assembly is operable to separate the blade root from the blade bearing when mounted, and when the rotor blade is not otherwise secured to the blade bearing. The system can be used in a method for separating a rotor blade from a rotor hub of a wind turbine.

Description

SYSTEM AND METHOD FOR SEPARATING A ROTOR BLADE FROM A BLADE BEARING

OF A WIND TURBINE

Cross-reference to Related Applications

This application claims the benefit of United States Provisional Patent Application USSN 62/923,693 filed October 21, 2019, the entire contents of which is herein incorporated by reference.

Field

This application relates to wind turbines, more specifically to systems and methods for separating a rotor blade from a wind turbine.

Background

Wind turbines occasionally need repair or replacement of one or more of the rotor blades or of blade bearing of the rotor hub. To accomplish such repair or replacement, the one or more rotor blades must be separated from the blade bearing on the rotor hub, and then the one or more rotor blades rejoined or one or more new rotor blades joined to the blade bearing. Separating a rotor blade on a rotor hub is difficult and dangerous given the size and weight of the rotor blade, the fact that root studs need to be removed or provided at a root of the rotor blade and the blade bearing on the rotor hub during the process, under the often windy conditions at a top of the wind turbine.

There remains a need for a system and method for separating a rotor blade from a blade bearing of a rotor hub of a wind turbine.

Summary

A system for separating a rotor blade from a rotor hub of a wind turbine is provided. The system comprises a jacking assembly mountable between a blade root of the rotor blade and a blade bearing of the rotor hub, the jacking assembly mountable in at least one open unthreaded aperture in the blade bearing and in at least one corresponding open threaded aperture in the blade root, the jacking assembly capable of supporting a weight of the rotor blade when the rotor blade is not otherwise joined to the blade bearing, the jacking assembly operable to separate the blade root from the blade bearing when the jacking assembly is mounted in the at least one open unthreaded aperture and the at least one corresponding open threaded aperture, and when the rotor blade is not otherwise joined to the blade bearing.

There is also provided a method for separating a rotor blade from a rotor hub of a wind turbine, the rotor blade joined to the rotor hub by a plurality of threaded root studs threadingly secured in threaded apertures in a blade root of the rotor blade, the plurality of threaded root studs extending through a corresponding plurality of unthreaded apertures in a blade bearing of the rotor blade and secured in the plurality of unthreaded apertures with a corresponding plurality of threaded nuts, the method comprising: removing a first sufficient number of the root studs and corresponding nuts to provide a plurality of open threaded apertures and a corresponding plurality of open non-threaded apertures while retaining a second sufficient number of nuts to keep the rotor blade joined to the rotor hub; mounting at least one jacking assembly in at least one of the plurality of open threaded apertures and corresponding plurality of open non-threaded apertures, the at least one jacking assembly connecting the blade root to the blade bearing and capable of bearing a weight of the rotor blade; removing all of the second sufficient number of nuts; and, operating the at least one jacking assembly to separate the blade root from the blade bearing.

The system preferably comprises and the method preferably employs a plurality of the jacking assembly, for example two, three, four or more jacking assemblies. The jacking assembly or assemblies may be mounted on the blade bearing and blade root at annular positions that lead to a balanced application of forces across the blade root so that the blade root can be separated evenly from the blade bearing.

In some embodiments, the at least one jacking assembly comprises at least one threaded jack stud insertable through the at least one open unthreaded aperture in the blade bearing, and threadable into the at least one corresponding open threaded aperture in the blade root, the at least one threaded jack stud movable within the at least one open unthreaded aperture and threadingly secured in the at least one corresponding open threaded aperture.

In some embodiments, the at least one open unthreaded aperture may comprise a first open unthreaded aperture and a second open unthreaded aperture, and the at least one corresponding open threaded aperture comprises a first open threaded aperture corresponding to the first open unthreaded aperture and a second open threaded aperture corresponding to the second open unthreaded aperture. In some embodiments, the jacking assembly may comprise an upper mounting plate and a lower mounting plate. The upper and lower mounting plates may be longitudinally separated. The upper mounting plate may comprise two first through-apertures aligned longitudinally with two corresponding second through-apertures in the lower mounting plate. The lower mounting plate may have a surface engaged with an upper surface of the blade bearing when the jacking assembly is mounted on the blade bearing.

In some embodiments, the jacking assembly may comprise a first threaded jack stud and a second threaded jack stud. The first threaded jack stud may be insertable through one of the first through-apertures, one of the corresponding second through-apertures and the first open unthreaded aperture. The first threaded jack stud may be further threadable into the first open threaded aperture to secure the first threaded jack stud in the first open threaded aperture thereby securing the jacking assembly to the blade root. The second threaded jack stud may be insertable through the other of the first through-apertures, the other of the corresponding second through-apertures and the second open unthreaded aperture. The second threaded jack stud may be further threadable into the second open threaded aperture to secure the second threaded jack stud in the second open threaded aperture thereby securing the jacking assembly to the blade root.

In some embodiments, the jacking assembly may comprise securing elements for preventing the upper mounting plate from translating upwardly along the first and second threaded jack studs when the first and second threaded jack studs are inserted through the first through-apertures. The securing elements may be nuts threaded on to the threaded jack studs, clips on the threaded jack studs, pins inserted through the threaded jack studs, or the like.

In some embodiments, the actuator may be connected to longitudinally spaced apart locations on the at least one threaded jack stud. The actuator may be operable to translate the blade root relative to the blade bearing. For example, the actuator may connect the upper mounting plate and the lower mounting plate, the actuator operable to translate the upper mounting plate in relation to the lower mounting plate thereby translating the blade root relative to the blade bearing. The actuator may be any sufficiently strong device for lifting the rotor blade. Some examples include a hydraulic cylinder, a pneumatic cylinder, a linear actuator or a mechanical spring-based actuator. The actuator is preferably a hydraulic cylinder. In some embodiments, the system or method may further comprise a blade root guide. The blade root guide is preferably mountable in one of the open unthreaded apertures of the blade bearing. The blade root guide may be engageable with the blade root and the blade bearing to prevent or reduce relative lateral movement of the blade root relative to the blade bearing. In one embodiment, the blade root guide may comprise: a vertically oriented strut; a horizontally oriented arm connected to the strut; a vertically oriented, vertically adjustable pin laterally offset from the strut, the vertically oriented pin mounted on the arm, the vertically oriented pin insertable through the other open unthreaded aperture of the blade bearing; and a horizontally oriented, horizontally adjustable upper abutment element and a horizontally oriented, horizontally adjustable lower abutment element, the upper abutment element having an abutment surface for engagement with the rotor hub and lower abutment element having an abutment surface for engagement with the rotor blade. In one embodiment, the upper abutment element may comprise a horizontally oriented, horizontally adjustable upper pin. In one embodiment, the lower abutment element may comprise an abutment plate pivotally connected to two horizontally oriented, horizontally adjustable lower pins.

In some embodiments of the method, the blade root may be connected to a lifting system after the blade root is separated from the blade bearing, and the at least one jacking assembly is disconnected from the blade root.

In some embodiments, the method may further comprise preventing or reducing lateral movement of the blade root relative to the blade bearing once the second sufficient number of nuts is removed, preferably by using one or more of the blade root guides. In one embodiment, four blade root guides are utilized. The blade root guides may be mounted on the blade bearing at annular positions that provide uniform stabilizing forces around circumferences of the blade bearing and the blade root.

In some embodiments, the method may further comprise attaching a plurality of lifting eyes in some of the plurality of open threaded apertures after the blade root has been separated from the blade bearing, connecting the plurality of lifting to a lifting system and disconnecting the at least one jacking assembly from the blade root.

Further features will be described or will become apparent in the course of the following detailed description. It should be understood that each feature described herein may be utilized in any combination with any one or more of the other described features, and that each feature does not necessarily rely on the presence of another feature except where evident to one of skill in the art.

Brief Description of the Drawings

For clearer understanding, preferred embodiments will now be described in detail by way of example, with reference to the accompanying drawings, in which:

Fig. 1 depicts a wind turbine having a rotor blade in a 6 o’clock position to be separated;

Fig. 2 depicts a top view of a blade bearing of a rotor hub showing the root studs and nuts that secure a blade root of the rotor blade to the blade bearing;

Fig. 3 depicts the blade bearing of Fig. 2 having some of the root studs and nuts removed;

Fig. 4 depicts a top perspective view of the blade bearing and the blade root after blade separation tooling comprising jacking assemblies and blade root guides have been installed and the blade root has not yet been separated from the blade bearing;

Fig. 5 depicts a side perspective view of the blade bearing and a blade root after jacking assemblies and blade root guides have been installed and the blade root has not yet been separated from the blade bearing;

Fig. 6 depicts a front view of one of the jacking assemblies seen in Fig. 4 and Fig. 5;

Fig. 7A depicts a perspective view of one of the blade root guides seen in Fig. 4 and

Fig. 5;

Fig. 7B depicts a side view of the blade root guide of Fig. 7A;

Fig. 8 depicts a top perspective view of the blade bearing and the blade root after blade separation tooling comprising jacking assemblies and blade root guides have been installed and the blade root has been separated from the blade bearing;

Fig. 9 depicts a side perspective view of the blade bearing and a blade root after jacking assemblies and blade root guides have been installed and the blade root has been separated from the blade bearing; Fig. 10A depicts a side perspective view of the blade root separated from the blade bearing in context with the rotor hub with lifting eyes installed on the blade root;

Fig. 10B depicts Fig. 10A with the rotor hub removed showing the blade separation tooling mounted on the blade bearing and blade root;

Fig. 10C depicts a top view of the blade root seen in Fig. 10A with the blade separation tooling removed but showing locations of the lifting eyes;

Fig. 11A depicts a front top perspective view of the wind turbine showing a crane mounted atop thereof and lifting lines connecting the blade root to the crane;

Fig. 11 B depicts a magnified front view of Fig. 11A showing where the lifting lines connect to the blade root; and,

Fig. 11 C depicts a magnified side view of Fig. 11 B.

Detailed Description

With reference to the Figures, to separate a single rotor blade 110 from a rotor hub 105 of a rotor 103 atop a tower 102 of a wind turbine 100, the rotor 103 is yawed to a suitable direction depending on wind direction and the rotor blade 110 is moved to the 6 o’clock position as shown in Fig. 1 where the rotor blade 110 points vertically downward from the rotor hub 105. Moving the rotor blade 110 can be accomplished using a turning gear on a highspeed side of a gearbox of the wind turbine 100. A highspeed brake is applied to stop the rotor 103 from turning and then a high-speed rotor lock is engaged to prevent the rotor 103 from turning during the separation procedure.

The rotor hub 105 comprises a blade bearing 107 to which a blade root 111 of the rotor blade 110 is connected during normal operation of the wind turbine 100. Connection of the blade root 111 to the blade bearing 107 is accomplished with a plurality of threaded root studs

112 (only one labeled) which are threaded into a corresponding plurality of threaded apertures

113 (only one labeled) in the blade root 111 and secured in a corresponding plurality of non- threaded apertures 116 (only one labeled) in the blade bearing 107 by a plurality of nuts 114 (only one labeled). With the rotor blade 110 pitched to -90° (trailing edge forward), locations of each of the root studs 112, nuts 114, threaded aperture 113 and non-threaded apertures 116 are assigned identity numbers, as shown in Fig. 2 and Fig. 3 which illustrates an embodiment where there are fifty-four annularly arranged root studs 112, nuts 114, threaded apertures 113 and non- threaded apertures 116. Locations are numbered sequentially as 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35,

36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53 and 54, with locations 1 and 54 located as far to the front of the rotor 103 as possible, as indicated by arrow A, the front being defined as a rotor side of a nacelle 101 of the wind turbine 100. The corresponding root stud 112, nut 114, threaded aperture 113 and non-threaded aperture 116 at one location are identified by the same identity number. For example, the root stud 112 at location 23, is threaded into the threaded aperture 113 at location 23 and secured in the non-threaded aperture 116 at location 23 by the nut 114 at location 23. The numbering of locations is arbitrary provided the numbering is consistently adhered in order to correctly identify root studs, nuts, threaded apertures and non-threaded apertures during the separation procedure.

Once the identity numbers have been assigned to locations, the rotor blade 110 is pitched to a position that allows the removal of nuts 114 and root studs 112, which are inaccessible to a nut and/or root stud removal tool (e.g. a torque wrench) when the rotor blade 110 is pitched to -90° (trailing edge forward), for example the nuts 114 at locations 5, 6, 7, 12, 13, 14, 15, 16, 17, 22, 23, 24, 32, 33, 34, 48, 49 and 50. The nuts 114 at these locations are removed. The root studs 112 at locations 6 and 49 are also removed if the rotor blade 110 is to be eventually lowered all the way to the ground using the simplified procedure described below. The rotor blade 110 is then pitched back to -90° (trailing edge forward), and the pitch system is completely locked to prevent any further pitching of the rotor blade 110. The exact nuts to be removed at this stage depends on the type of rotor blade and the accessibility of the nuts when the rotor blade is pitched to -90° (trailing edge forward). Inaccessible nuts and root studs are thus removed prior to completely locking the pitch system.

After locking the pitch system, a sufficient number of the root studs 112 and nuts 114 are further removed to be able to install blade separation tooling at suitable locations on the blade bearing 107 and blade root 111. In one embodiment, the nuts 114 and root studs 112 at locations 4, 8, 9, 10, 19, 20, 36, 37, 46, 47, 48 and 52 are removed, and the nuts 114 at locations 3, 11, 18, 21, 25, 31, 35, 38, 39, 45 and 51 are removed to provide an arrangement of remaining nuts 114 as shown in Fig. 3. The root studs 112 at locations 20 and 36 may be removed only if the rotor blade 110 is to be eventually lowered all the way to the ground using the simplified procedure described below.

The blade separation tooling comprises at least one jacking assembly, for example a plurality of jacking assemblies, for example two jacking assemblies 120, as shown in Fig. 4 and Fig. 5. The blade separation tooling further comprises at least one blade root guide, for example a plurality of blade root guides, for example four blade root guides 140, as shown in Fig. 4 and Fig. 5. The jacking assemblies 120 provide an adjustable connection between the blade bearing 107 and the blade root 111 so that when all of threaded root studs 112 are eventually removed, the jacking assemblies can be employed to separate the blade root 111 from the blade bearing 107, or conversely bring the blade root 111 back to the blade bearing 107 in proper alignment to reinsert the threaded root studs 112. The blade root guides 140 deter or prevent lateral relative movement between the blade bearing 107 and the blade root 111 when all of the threaded root studs 112 are removed in order to stabilize the blade root 111 during separation or rejoining of the blade root 111 to the blade bearing 107.

As shown in Fig. 6, each of the jacking assemblies 120 comprises an actuator 121, a top jacking plate 122, a bottom plate 123 and two threaded long jack studs 124. In use, the actuator 121 is pivotally linked to the top jacking plate 122 and the bottom plate 123 such that actuation of the actuator 121 can cause the top jacking plate 122 and the bottom plate 123 to move toward or away from each other. The top jacking plate 122 and the bottom plate 123 comprise plate apertures therein proximate the respective ends thereof to permit insertion of the long jack studs 124 therethrough. Upward movement of the top jacking plate 122 on the long jack studs 124 is prevented by securing elements on the long jack stud 124, for example stop nuts 125 threaded on to tops of the threaded long jack studs 124. In use, the bottom plate 123 moves along the long jack studs 124 in response to actuation of the actuator 121. The long jack studs 124 are threaded to be matingly engageable with the threaded apertures 113 in the blade root 111. The actuator may be any suitable actuator for linearly displacing the top and bottom plates with respect to each other, for example a hydraulic cylinder, a pneumatic cylinder, a linear actuator or a mechanical spring-based actuator.

To install the jacking assemblies 120 on the blade bearing 107 and blade root 111, the long jack studs 124 are inserted through open non-threaded apertures 116 in the blade bearing 107 and threaded into corresponding open threaded apertures 113 in the blade root 111. The corresponding open apertures 116, 113 are apertures which have had the nuts 114 and root studs 112 removed. The corresponding open apertures are close enough together to match a lateral distance between the plate apertures in the top jacking plate 122 and a lateral distance between the plate apertures in the bottom plate 123 to permit installation of the plates 122, 123 on the long jack studs 124. For example, when two jacking assemblies 120 are used as illustrated in Fig. 8, four long jack studs 124 (two pairs) may be installed by threading the long jack studs 124 into the threaded aperture 113 at locations 8, 10, 48 and 46. The actuator 121 of each jacking assembly 120 may then be pivotally pinned to a bottom plate clevis 128 on the respective bottom plate 123 using a bottom pin 126, and the bottom plate 123 slid onto the respective pair of long jack studs 124 to rest on the blade bearing 107. The top jacking plate 122 of each jacking assembly 120 may then be slid onto one of the pairs of long jack studs 124 and pivotally pinned to the actuator 121 using a top pin 127 inserted through a top plate clevis 129 on the top jacking plate 122. The stop nuts 125 are threaded on to the threaded long jack studs 124 above the top jacking plate 122 to prevent the top jacking plate 122 from sliding upward. In this way, a connection between the blade bearing 107 and the blade root 111 is formed using the jacking assemblies 120.

As shown in Fig. 7 A and Fig. 7B, each of the blade root guides 140 comprises a vertically oriented strut 141 having a top end 142 and a bottom end 143, a horizontally extending arm 144, a vertically oriented holding pin 145 comprising a tapered tip 149 inserted though and threadingly mated with a vertically oriented aperture in the arm 144, a horizontally oriented top spacing pin 146 inserted through and threadingly mated with a horizontally oriented threaded aperture in the top end 142 of the strut 141, two horizontally oriented bottom spacing pins 147 inserted through and threadingly mated with corresponding horizontally oriented threaded apertures in the bottom end 143 of the strut 141 and a bottom abutment plate 148 pivotally attached to the bottom spacing pins 147 at a same side of the strut 141 from which the arm 144 extends.

The blade root guides 140 are installed on the blade bearing 107 by inserting the holding pin 145 through one of the open non-threaded apertures 116 so that a bottom surface 151 of the arm 144 rests on a top surface of the blade bearing 107 and the tapered tip 149 of the holding pin 145 is a sufficient distance below the top surface of the blade bearing 107 to keep the holding pin 145 in the open unthreaded aperture 116 of the blade bearing 107 while lowering the rotor blade 110 away from the rotor hub 105. The holding pin 145 also acts as a stabbing pin during the final stage of raising the rotor blade 110 to the rotor hub 105 to help ensure that the blade root 111 is properly aligned with the blade bearing 107 during joining of the blade root 111 to the blade bearing 107. The holding pin 145 is threadingly engaged with the aperture in the arm 144 to permit vertical adjustment of the holding pin 145. With the blade root guide 140 so installed on the blade bearing 107, the top spacing pin 146 is horizontally adjusted so that a tip 152 of the top spacing pin 146 abuts an inner wall of the rotor hub 105 and the two horizontally oriented bottom spacing pins 147 are adjusted so that the bottom abutment plate 148 abuts an inner wall of the rotor blade 110 in a slidingly engaged manner. As the rotor blade 110 is raised or lowered, the top spacing pin 146 and the bottom abutment plate 148 prevent or reduce lateral movement of the blade root 111 with respect to the blade bearing 107, while the bottom abutment plate 148 can slide along the inner wall of the rotor blade 110. A sufficient number of blade root guides 140 should be installed to prevent or reduce relative lateral movement in all lateral directions. In the embodiment shown in Fig. 4 and Fig. 5, there are four blade root guides 140 installed at locations 4, 19, 37 and 52.

With the jacking assemblies 120 and blade root guides 140 installed, actuators 121 of the jacking assemblies 120 are actuated until the weight of the rotor blade 110. In the embodiment of the jacking assembly illustrated in Fig. 6, extension of the hydraulic cylinder 121 draws the long jack studs 124 upward, provides an upward force on the blade root 111 thereby clamping the blade root 111 to the blade bearing 107. A differing construction of the jacking assembly may dictate a different actuation procedure. The remaining nuts 114 (see Fig. 3) are then removed so that only the jacking assemblies 120 are preventing the blade root

111 from vertically separating from the blade bearing 107. For added stability and safety, a tailing crane may be connected to a tip 119 of the rotor blade 110 and used to help ensure that the remaining root studs 112 on the blade root 111 remain in line with the non-threaded apertures 116 in the blade bearing 107. Instead of a tailing crane, a blade clamp may be clamped to the rotor blade and used to provide similar added stability and safety. The tailing crane (or blade clamp) assists the blade root guides 140 in preventing or reducing lateral movement of the blade root 111 with respect to the blade bearing 107. Further, the top spacing pin 146 and the bottom spacing pins 147 may be adjusted to position the remaining root studs

112 in the centres of the non-threaded apertures 116.

In the embodiment of the jacking assembly illustrated in Fig. 6, retraction of the hydraulic cylinder 121 pushes the long jack studs 124 downward, which pushes the blade root 111 away from the blade bearing 107 thereby separating the blade root 111 from the blade bearing 107, as seen in Fig. 8 and Fig. 9. The blade root guides 140 remain installed on the blade bearing 107 and operate as described above. The jacking assemblies 120 are used to lower the blade root 111 a desired distance (e.g. 300 mm) below the blade bearing 107. If a tailing crane or blade clamp is also being used, the tailing crane or blade clamp may be continuously adjusted to ensure that the tip 119 of the rotor blade 110 is lowered at the same rate as the blade root 111.

At this stage, the blade bearing 107 is accessible for maintenance work. If the rotor blade 110 does not require repair or replacement, the rotor blade 110 can remain suspended. In this eventuality, for further safety, the rotor blade 110 can be further stabilized using a blade sock or a blade clamp connected to a lifting system. In one embodiment, a blade clamp as described in co-pending United States patent application USSN 62/882,298 filed August 2, 2019, the entire contents of which is herein incorporated by reference, may be used to further stabilize the rotor blade. Typically, the blade sock or blade clamp is installed on the rotor blade prior to separating the blade root from the blade bearing. The lifting system connected to the blade sock or blade clamp may be ground-based or mounted atop the wind tower. In one embodiment, the lifting system comprises a lifting crane.

If repair or replacement of the rotor blade 110 is required, or if the maintenance work on the blade bearing 107 requires a bearing rotation, then the blade root 111 will need to be further disconnected from the blade bearing 107 by removing the jacking assemblies 120 and the blade root guides 140. If repair or replacement of the rotor blade 110 is required, the rotor blade 110 will also need to be lowered to the ground.

In these eventualities, a blade sock or a blade clamp connected to a lifting system could be used to help support the rotor blade, and help lower the rotor blade all the way to the ground, if required. However, in a simplified procedure, a blade sock or a blade clamp is not used. Instead, with the blade root 111 separated from the blade bearing 107, one or more lifting attachments are installed in one or more available open threaded apertures 113 in the blade root 111. As seen in Fig. 10A, Fig. 10B and Fig. 10C, in one embodiment, the one or more lifting attachments may be four lifting eyes 160 installed in the open threaded apertures 113 of the blade root 111 at locations 6, 20 36 and 49, which previously had the root studs 112 removed. Rearward lifting eyes 160a are connected to taglines 173, which lead to ground- based winches. Forward lifting eyes 160b are connected to first slings 171 extending from a spreader bar 172 connected by second slings 174 to a connector 175 (e.g. a hook) of a heavy- duty lifting system 170 mounted atop the tower 102 in the nacelle 101 of the wind turbine 100 (see Fig. 11 A, Fig. 11B and Fig. 11C). While any sufficiently robust lifting system may be used, in one embodiment, the heavy-duty lifting system 170 may be a nacelle-mounted lift system as described in United States Patent Application USSN 16/552,072 filed August 27, 2019, the entire contents of which is herein incorporated by reference.

The spreader bar 172 is positioned over and in front of the rotor hub 105, and the taglines 173 and the first slings 171 are connected to the respective lifting eyes 160a and 160b. The first slings 171 extend down from the spreader bar 172 on either side of a nose 105a of the rotor hub 105. Once the taglines 173 and first slings 171 are connected, the lifting system 170 is operated to lift the rotor blade 110 until the jacking assemblies 120 have no load. The jacking assemblies 120 are then uninstalled from the blade root 111 including removing the long jack studs 124 from the respective threaded apertures 113 of the blade root 111 so that the blade bearing 107 is free to move independently of the rotor blade 110. The ability of the blade bearing 107 to be free move independently of the rotor blade 110 is especially important where the maintenance work involves a bearing rotation. The blade root guides 140 are also uninstalled to not interfere while rotating the blade bearing 107. The heavy-duty lifting system 170 supports the rotor blade 110 while the maintenance work is performed, and the tailing crane may be used to assist in keeping the rotor blade 110 aligned properly during the maintenance work on the blade bearing 107.

To rejoin the rotor blade 110 to the rotor hub 105, the procedure is essentially reversed. The blade root guides 140 are reinstalled in the same unthreaded apertures 116 in the blade bearing 107 and clamped in place using temporary bridge clamps. The taglines 173, the blade root guides 140 and the tailing crane are adjusted, if necessary, until the long jack studs 124 of the jacking assemblies 120 are reinstalled through the unthreaded apertures 116 of the blade bearing 107 into the threaded apertures 113 in the blade root 111 below. The holding pins 145 of the blade root guides 140 can be used as stabbing pins, each holding pin 145 independently threadable up and down. The hydraulic cylinders 121 of the jacking assemblies 120 are actuated, in this case extended, to lift the blade root 111 up toward the blade bearing 107 to take the weight of the rotor blade 110 off the lifting system 170. The rigging (taglines 174 and first slings 171) are removed from the lifting eyes 160, and the lifting eyes 160 removed from the blade root 111. The hydraulic cylinders 121 of the jacking assemblies 120 are actuated again, in this case extended, to further lift the blade root 111 up to the blade bearing 107 as far as possible while ensuring that the bridge clamps can be removed. The bridge clamps are then removed to permit the jacking assemblies 120 to raise the blade root 111 all the way up to the blade bearing 107. Throughout the lifting, the tailing crane (if used) and blade root guides 140 can be adjusted to keep the root studs 112 aligned with the unthreaded apertures 116 in the blade bearing 107. Accessible nuts 114 are then reinstalled on corresponding root studs 112. The jacking assemblies 120 and blade root guides 140 are uninstalled. All remaining nuts 114 are then reinstalled on corresponding root studs 112. Finally, all locks are disengaged to permit free rotation of the rotor 103.

The novel features will become apparent to those of skill in the art upon examination of the description. It should be understood, however, that the scope of the claims should not be limited by the embodiments, but should be given the broadest interpretation consistent with the wording of the claims and the specification as a whole.

Claims

Claims:

1. A system for separating a rotor blade from a rotor hub of a wind turbine, the system comprising a jacking assembly mountable between a blade root of the rotor blade and a blade bearing of the rotor hub, the jacking assembly mountable in at least one open unthreaded aperture in the blade bearing and in at least one corresponding open threaded aperture in the blade root, the jacking assembly capable of supporting a weight of the rotor blade when the rotor blade is not otherwise joined to the blade bearing, the jacking assembly operable to separate the blade root from the blade bearing when the jacking assembly is mounted in the at least one open unthreaded aperture and the at least one corresponding open threaded aperture, and when the rotor blade is not otherwise joined to the blade bearing.

2. The system of claim 1 , wherein the at least one jacking assembly comprises: at least one threaded jack stud insertable through the at least one open unthreaded aperture in the blade bearing, and threadable into the at least one corresponding open threaded aperture in the blade root, the at least one threaded jack stud movable within the at least one open unthreaded aperture and threadingly secured in the at least one corresponding open threaded aperture; and, an actuator connected to longitudinally spaced apart locations on the at least one threaded jack stud, the actuator operable to translate the blade root relative to the blade bearing.

3. The system of claim 1, wherein the at least one open unthreaded aperture comprises a first open unthreaded aperture and a second open unthreaded aperture, and the at least one corresponding open threaded aperture comprises a first open threaded aperture corresponding to the first open unthreaded aperture and a second open threaded aperture corresponding to the second open unthreaded aperture, wherein the jacking assembly comprises: an upper mounting plate and a lower mounting plate, the upper and lower mounting plates longitudinally separated, the upper mounting plate comprising two first through- apertures aligned longitudinally with two corresponding second through-apertures in the lower mounting plate, the lower mounting plate having a surface engaged with an upper surface of the blade bearing when the jacking assembly is mounted on the blade bearing; a first threaded jack stud insertable through one of the first through-apertures, one of the corresponding second through-apertures and the first open unthreaded aperture, the first threaded jack stud further threadable into the first open threaded aperture to secure the first threaded jack stud in the first open threaded aperture thereby securing the jacking assembly to the blade root; a second threaded jack stud insertable through the other of the first through-apertures, the other of the corresponding second through-apertures and the second open unthreaded aperture, the second threaded jack stud further threadable into the second open threaded aperture to secure the second threaded jack stud in the second open threaded aperture thereby securing the jacking assembly to the blade root; securing elements for preventing the upper mounting plate from translating upwardly along the first and second threaded jack studs when the first and second threaded jack studs are inserted through the first through-apertures; an actuator connecting the upper mounting plate and the lower mounting plate, the actuator operable to translate the upper mounting plate in relation to the lower mounting plate thereby translating the blade root relative to the blade bearing.

4. The system of claim 2 or claim 3, wherein the actuator is a hydraulic cylinder.

5. The system of any one of claims 1 to 4, comprising a plurality of the jacking assembly.

6. The system of any one of claims 1 to 5, further comprising a blade root guide mountable in another open unthreaded aperture of the blade bearing, the blade root guide engageable with the blade root and the blade bearing to prevent or reduce relative lateral movement of the blade root relative to the blade bearing.

7. The system of claim 6, wherein the blade root guide comprises: a vertically oriented strut; a horizontally oriented arm connected to the strut; and, a vertically oriented, vertically adjustable pin laterally offset from the strut, the vertically oriented pin mounted on the arm, the vertically oriented pin insertable through the other open unthreaded aperture of the blade bearing; a horizontally oriented, horizontally adjustable upper abutment element and a horizontally oriented, horizontally adjustable lower abutment element, the upper abutment element having an abutment surface for engagement with the rotor hub and lower abutment element having an abutment surface for engagement with the rotor blade.

8. The system of claim 7, wherein the upper abutment element comprises a horizontally oriented, horizontally adjustable upper pin and the lower abutment element comprises an abutment plate pivotally connected to two horizontally oriented, horizontally adjustable lower pins.

9. A method for separating a rotor blade from a rotor hub of a wind turbine, the rotor blade joined to the rotor hub by a plurality of threaded root studs threadingly secured in threaded apertures in a blade root of the rotor blade, the plurality of threaded root studs extending through a corresponding plurality of unthreaded apertures in a blade bearing of the rotor blade and secured in the plurality of unthreaded apertures with a corresponding plurality of threaded nuts, the method comprising: removing a first sufficient number of the root studs and corresponding nuts to provide a plurality of open threaded apertures and a corresponding plurality of open non-threaded apertures while retaining a second sufficient number of nuts to keep the rotor blade joined to the rotor hub; mounting at least one jacking assembly in at least one of the plurality of open threaded apertures and corresponding plurality of open non-threaded apertures, the at least one jacking assembly connecting the blade root to the blade bearing and capable of bearing a weight of the rotor blade; removing all of the second sufficient number of nuts; and, operating the at least one jacking assembly to separate the blade root from the blade bearing.

10. The method of claim 9, wherein the blade root is connected to a lifting system after the blade root is separated from the blade bearing, and the at least one jacking assembly is disconnected from the blade root.

11. The method of claim 9 or claim 10, wherein the at least one jacking assembly comprises a jacking assembly comprising: at least one threaded jack stud threadable into at least one of the open threaded apertures in the blade root and insertable through at least one of the corresponding open unthreaded apertures in the blade bearing, the at least one threaded jack stud movable within the at least one corresponding open unthreaded aperture and threadingly secured in the at least one open threaded aperture; and, an actuator connected to longitudinally spaced apart locations on the at least one threaded jack stud, the actuator operable to translate the blade root relative to the blade bearing.

12. The method of claim 11, wherein: the at least one threaded jack stud comprises a first threaded jack stud and a second threaded jack stud; the at least one of the open threaded apertures comprises a first open threaded aperture and a second open threaded aperture; the at least one of the corresponding open unthreaded apertures comprises a first corresponding open unthreaded aperture and a second corresponding open unthreaded aperture, and wherein the jacking assembly further comprises an upper mounting plate and a lower mounting plate, the upper and lower mounting plates longitudinally separated, the upper mounting plate comprising two first through-apertures aligned longitudinally with two corresponding second through-apertures in the lower mounting plate, the lower mounting plate having a surface engaged with an upper surface of the blade bearing when the jacking assembly is mounted on the blade bearing, wherein the first threaded jack stud is insertable through one of the first through-apertures, one of the corresponding second through-apertures and the first corresponding open unthreaded aperture, the first threaded jack stud further threadable into the first open threaded aperture to secure the first threaded jack stud in the first open threaded aperture thereby securing the jacking assembly to the blade root, and wherein the second threaded jack stud is insertable through the other of the first through- apertures, the other of the corresponding second through-apertures and the second corresponding open unthreaded aperture, the second threaded jack stud further threadable into the second open threaded aperture to secure the second threaded jack stud in the second open threaded aperture thereby securing the jacking assembly to the blade root, wherein the jacking assembly further comprises securing elements for preventing the upper mounting plate from translating upwardly along the first and second threaded jack studs when the first and second threaded jack studs are inserted through the first through-apertures, and wherein the actuator connects the upper mounting plate and the lower mounting plate, the actuator operable to translate the upper mounting plate in relation to the lower mounting plate thereby translating the blade root relative to the blade bearing.

13. The method of any one of claims 9 to 12, wherein the at least one jacking assembly comprises two jacking assemblies.

14. The method of any one of claims 9 to 13, further comprising preventing or reducing lateral movement of the blade root relative to the blade bearing once the second sufficient number of nuts is removed.

15. The method of claim 14, wherein the preventing or reducing lateral movement of the blade root is accomplished with at least one blade root guide mounted on the blade bearing, the at least one blade root guide comprises a blade root guide comprising: a vertically oriented strut; a horizontally oriented arm connected to the strut; a vertically oriented, vertically adjustable pin laterally offset from the strut, the vertically oriented pin mounted on the arm, the vertically oriented pin insertable through a designated open unthreaded aperture of the blade bearing; a horizontally oriented, horizontally adjustable upper abutment element and a horizontally oriented, horizontally adjustable lower abutment element, the upper abutment element having an abutment surface for engagement with the rotor hub and lower abutment element having an abutment surface for engagement with the rotor blade.

16. The method of claim 15, wherein the at least one blade root guide comprises four blade root guides.

17. The method of any one of claims 9 to 16, further comprising: attaching a plurality of lifting eyes in some of the plurality of open threaded apertures after the blade root has been separated from the blade bearing; connecting the plurality of lifting to a lifting system; and, disconnecting the at least one jacking assembly from the blade root.