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By a News Reporter-Staff News Editor at Energy Business Daily -- According to news reporting originating from Alexandria, Virginia, by NewsRx journalists, a patent by the inventors Hansen, Jesper Hermann (Varde, DK), Petersen, Henrik (Horens, DK), Torborg, Jens (Arre, DK), filed on December 13, 2017, was published online on February 1, 2022.
The assignee for this patent, patent number 11235956, is Vestas Wind Systems A/S (Aarhus N., Denmark).
Reporters obtained the following quote from the background information supplied by the inventors: “Wind turbines are used to produce electrical energy using a renewable resource and without combusting a fossil fuel. Generally, a wind turbine converts kinetic energy from the wind into electrical power. A horizontal-axis wind turbine includes a tower, a nacelle located at the apex of the tower, and a rotor having a plurality of blades extending from a hub and supported in the nacelle by means of a shaft. The shaft couples the rotor either directly or indirectly with a generator, which is housed inside the nacelle. Consequently, as wind forces the blades to rotate, electrical energy is produced by the generator.
“Blades may be attached to a wind turbine in a variety of ways. One such way is to first mount a rotor hub to the nacelle, and then to attach blades one by one to the installed hub. In other words, the rotor may be assembled on the nacelle by first installing the hub to the nacelle and subsequently hoisting each individual blade, such as by a crane, toward the nacelle and attaching each blade to the hub. However, this process is expensive and time-consuming, as it requires separately hoisting the hub and each individual blade, and requires personnel to couple each blade to the hub above ground level.
“Another way, commonly referred to as a “full rotor lift,” involves preassembling the blades and hub at ground level and subsequently lifting the whole rotor as a single unit and mounting it to the nacelle. In this method, the rotor is typically lifted from a horizontal orientation (e.g., flat on the ground), and is turned while suspended into a generally vertical orientation for nacelle attachment. The initial rotor lift from the horizontal orientation is usually performed using a primary crane, which grips the rotor at a dedicated lifting point on the hub. The lifting point may be provided via a hub yoke, for example, which may be positioned on a flank of the hub between two adjacent blades. Examples of such yokes are disclosed by WO2008089763 and U.S. Patent Publication No. 2014/0319091. When the rotor is suspended in this manner by the primary crane, the blade which extends in the opposite direction from the lifting point may extend downward toward the ground. Thus, the downward pointing blade must usually be supported off the ground by a secondary crane to prevent the blade from impacting the ground. The rotor may then be turned into a generally vertical orientation by the combined, coordinated action of the primary and secondary cranes. This process may be reversed in order to remove the rotor from the wind turbine, such as for maintenance or replacement purposes.
“As such, a conventional full rotor lift process is undesirably complicated. For example, the need for multiple cranes to install a single rotor is undesirable. Likewise, the need for a dedicated interface between the rotor and the primary crane, such as a hub yoke, is undesirable. Moreover, the concerted actions of the primary and secondary cranes may be difficult to properly execute in order to suitably install the rotor.
“Manufacturers of wind turbines and wind turbine components continually strive to improve systems and methods associated with the assembly of wind turbines. It would therefore be desirable to provide an improved full rotor lift system and method for a wind turbine.”
In addition to obtaining background information on this patent, NewsRx editors also obtained the inventors’ summary information for this patent: “In one embodiment, a method of lifting a rotor of a wind turbine, the rotor having a center of gravity and including a hub and first, second, and third blades projecting outwardly from the hub at locations circumferentially distributed thereabout, includes positioning first and second slings around the first and second blades, respectively, to define first and second lifting zones delineating a lifting envelope, wherein the lifting envelope encompasses the center of gravity. The method also includes lifting the rotor above a surface via the first and second slings wherein the rotor is in one of a substantially horizontal or substantially vertical orientation, with the aid of at least one of the first and second slings while continuing to fully support the rotor by the first and second slings. Reorienting the rotor may include activating at least one sling actuator. For example, activating the at least one sling actuator may adjust a length of at least one of the first and second slings, or may apply a friction drive to at least one of the first and second slings. In one embodiment, the at least one sling actuator includes at least one of a hydraulic actuator, a jack, a winch, or a friction drive.
“In one embodiment, reorienting the rotor includes adjusting a pitch of at least one of the first and second blades. For example, reorienting the rotor may include activating at least one pitching system of the rotor to adjust the pitch of at least one of the first and second blades. In one embodiment, activating the at least one pitching system of the rotor causes the first blade to rotate in a clockwise direction while causing the second blade to rotate in a counterclockwise direction.
“In one embodiment, the method further includes positioning at least one wedge between at least one of the first and second blades and the respective sling to expand the lifting envelope.
“In another embodiment, a full rotor lift system for lifting a rotor of a wind turbine, the rotor having a center of gravity and including a hub and first, second, and third blades projecting outwardly from the hub at locations circumferentially distributed thereabout in equal intervals, includes first and second slings for attaching to the first and second blades, respectively, to define first and second lifting zones delineating a lifting envelope. The lifting envelope includes the center of gravity such that the first and second slings are capable of fully supporting the rotor above a surface in a horizontal orientation. The system further includes at least one actuator for reorienting the rotor between a horizontal and a vertical orientation with the aid of at least one of the first and second slings. The at least one actuator may include at least one sling actuator. For example, the at least one sling actuator may be operable to adjust a length of at least one of the first and second slings. In one embodiment, the at least one sling actuator includes at least one of a hydraulic actuator, a jack, a winch, or a friction drive.
“In one embodiment, the at least one actuator includes at least one pitching system of the rotor. For example, the at least one pitching system may be operable to rotate the first blade in a clockwise direction while rotating the second blade in a counterclockwise direction.”
The claims supplied by the inventors are:
“1. A method of lifting a rotor of a wind turbine, the rotor having a center of gravity and including a hub and first, second, and third blades projecting outwardly from the hub at locations circumferentially distributed thereabout, the method comprising: positioning first and second slings around the first and second blades, respectively, to define first and second lifting zones delineating a lifting envelope, wherein the lifting envelope encompasses the center of gravity; lifting the rotor above a surface via the first and second slings wherein the rotor is in one of a substantially horizontal or substantially vertical orientation while being fully supported via the first and second slings; and reorienting the rotor toward the other of a substantially horizontal or substantially vertical orientation, with the aid of at least one of the first and second slings while continuing to fully support the rotor by the first and second slings.
“2. The method of claim 1, wherein reorienting the rotor includes activating at least one sling actuator.
“3. The method of claim 2, wherein activating the at least one sling actuator adjusts a length of at least one of the first and second slings.
“4. The method of claim 2, wherein activating the at least one sling actuator applies a friction drive to at least one of the first and second slings.
“5. The method of claim 2, wherein the at least one sling actuator includes at least one of a hydraulic actuator, a jack, a winch, or a friction drive.
“6. The method of claim 1, wherein reorienting the rotor includes adjusting a pitch of at least one of the first and second blades.
“7. The method of claim 6, wherein reorienting the rotor includes activating at least one pitching system of the rotor to adjust the pitch of at least one of the first and second blades.
“8. The method of claim 7, wherein activating the at least one pitching system of the rotor causes the first blade to rotate in a clockwise direction while causing the second blade to rotate in a counterclockwise direction.
“9. The method of claim 1, further comprising positioning at least one wedge between at least one of the first and second blades and the respective sling to expand the lifting envelope.
“10. A full rotor lift system for lifting a rotor of a wind turbine, the rotor having a center of gravity and including a hub and first, second, and third blades projecting outwardly from the hub at locations circumferentially distributed thereabout in equal intervals, the system comprising: first and second slings for attaching to the first and second blades, respectively, to define first and second lifting zones delineating a lifting envelope, wherein the lifting envelope includes the center of gravity such that the first and second slings are capable of fully supporting the rotor above a surface in a horizontal orientation; and at least one actuator for reorienting the rotor between a horizontal orientation and a vertical orientation with the aid of at least one of the first and second slings.
“11. The system of claim 10, wherein the at least one actuator includes at least one sling actuator.
“12. The system of claim 11, wherein the at least one sling actuator is operable to adjust a length of at least one of the first and second slings.
“13. The system of claim 11, wherein the at least one sling actuator includes at least one of a hydraulic actuator, a jack, a winch, or a friction drive.
“14. The system of claim 10, wherein the at least one actuator includes at least one pitching system of the rotor.
“15. The system of claim 14, wherein the at least one pitching system is operable to rotate the first blade in a clockwise direction while rotating the second blade in a counterclockwise direction.
“16. The system of claim 10, further comprising at least one wedge operable to expand the lifting envelope when positioned between at least one of the first and second blades and the respective sling.”
For more information, see this patent: Hansen, Jesper Hermann. Method and system for lifting a wind turbine rotor. U.S. Patent Number 11235956, filed December 13, 2017, and published online on February 1, 2022. Patent URL: http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=11235956.PN.&OS=PN/11235956RS=PN/11235956
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