Patent Description:
Wind turbine generators are used to produce electrical energy using a renewable resource and without combusting a fossil fuel. A wind turbine generator converts kinetic energy from the wind into electrical energy, and includes a tower, a nacelle mounted atop the tower, a rotor hub rotatably supported by the nacelle, and a plurality of rotor blades attached to the hub. The hub is coupled to a generator housed inside the nacelle. Consequently, as wind forces the blades to rotate, electrical energy is produced by the generator.

One method of transporting the nacelle to a desired installation site involves the use of a so-called "world adapter transport solution". Such a transport solution is the subject of the assignee's <CIT>. This transport solution mounts a removable transport interface frame to each of the forward and aft ends of the nacelle. The nacelle is supported between a first forward trailer and a second aft trailer. The first trailer includes a transport frame at its aft end which engages with the transport interface frame on the forward end of the nacelle, and the second trailer includes a transport frame on its forward end which engages with the transport interface frame on the aft end of the nacelle. The first trailer is towed by a towing vehicle. Once the transport frames are engaged with the transport interface frames, lifting elements associated with the transport frames lift the nacelle up off the ground for transport. Upon delivery to the installation site the lifting elements then lower the nacelle to the ground. Alternatively, the nacelle can be lifted and lowered by lifting and lowering the suspension systems of the two trailers.

One method of positioning the generator and associated equipment such as the gearbox, as well as personnel, into the nacelle involves the use of an air ship to lower the payload through a hatch in the top of the nacelle. Such a method is disclosed in the assignee's <CIT>. Personnel or service equipment may be lowered to the nacelle using e.g. an airship or helicopter or drone or other aerial means.

<CIT> relates to a wind turbine which has a nacelle frame and a first hoist substantially permanently mounted on the frame. A method comprises the processes of hoisting a second, more powerful hoist and crane on the frame with the first hoist; removably mounting the second hoist and the crane on the nacelle frame; hoisting a winch using the second hoist and the crane on the frame, and removably mounting the winch on said frame; performing operations involving handling heavy parts employing said winch; and removing and lowering said winch, crane, and second hoist from the frame.

Further improvements in the delivery of equipment and personnel to the nacelle mounted atop the tower are desired.

In an exemplary embodiment, a wind turbine generator nacelle includes a nacelle frame having a first forward hub end and a second aft end, dedicated transport fittings at each of the ends of the nacelle frame, the fittings adapted to be engaged by transport frames on first and second transport trailers for supporting the nacelle frame for transport by the trailers, and a service platform mounted to the transport fittings on the aft end of the nacelle frame such that the service platform is cantilevered off of the aft end of the nacelle frame.

The nacelle has an internal service floor and the service platform is substantially coplanar with the internal service floor, thereby facilitating movement of equipment from the service platform to the interior of the nacelle. The service platform floor may be generally L-shaped having a leg portion and a foot portion, the leg portion abutting a rear wall of the nacelle and the foot portion spaced away from the rear wall of the nacelle. The rear wall of the nacelle can have an access door therein positioned to communicate between the leg portion of the service platform and the internal service floor of the nacelle. In a further aspect of the present invention, the nacelle can further include a hoist configured to extend through the access door out of the nacelle and configured to be slewed so as to be capable of transferring loads horizontally from the service platform to the nacelle and vertically from a support surface (e.g., the ground, deck of a ship, or a service platform adjacent a lower end of the tower) upwardly between the foot portion of the service platform and the rear wall of the nacelle. In an alternative embodiment, the rear wall of the nacelle can have an access door therein positioned to communicate between the service platform and the internal service floor of the nacelle and wherein the service platform functions as an emergency evacuation platform. Moreover, the rear wall of the nacelle can also have an electrical outlet accessible from the service platform. In this way, lights and other elements requiring electrical power may be used with the service platform.

In another exemplary embodiment, a method of transporting a wind turbine generator nacelle to an installation site and configuring it for use at the installation site includes providing a nacelle frame having a first forward hub end and a second aft end, providing dedicated transport fittings at each of the ends of the nacelle frame, engaging the transport fittings on the forward end of the nacelle frame with a first transport frame on a first transport trailer and engaging the transport fittings on the aft end of the nacelle frame with a second transport frame on a second transport trailer, supporting the nacelle frame above the ground with the first and second transport trailers, transporting the nacelle frame to the installation site with the first and second transport trailers, removing the nacelle frame from the first and second transport trailers, and mounting a service platform to the transport fittings on the aft end of the nacelle frame such that the service platform is cantilevered off of the aft end of the nacelle frame.

In yet another embodiment, a wind turbine generator includes a tower, a nacelle mounted atop the tower, the nacelle having a first forward hub end and a second aft end, a rotor hub rotatably supported by the nacelle on the forward end, a plurality of rotor blades mounted to the hub, dedicated transport fittings at each of the ends of the nacelle, the fittings adapted to be engaged by transport frames on first and second transport trailers for supporting the nacelle for transport by the trailers, and a service platform mounted to the transport fittings on the aft end of the nacelle such that the service platform is cantilevered off of the aft end of the nacelle.

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with a general description of the invention given above, and the detailed description given below, serve to explain the invention.

Referring to <FIG>, a wind turbine generator <NUM> includes a tower <NUM>, a nacelle <NUM> mounted atop the tower <NUM>, a rotor hub <NUM> rotatably supported by the nacelle <NUM>, and a plurality of rotor blades <NUM> mounted to the hub <NUM>. The hub <NUM> is operatively coupled to a generator (not shown) housed inside the nacelle <NUM>. In addition to the generator, the nacelle <NUM> also houses other components required for converting wind energy into electrical energy such as a gearbox, a transformer, a main shaft, a main shaft bearing, etc. (not shown).

Referring to <FIG>, <FIG>, <FIG>, and <FIG>, a service platform <NUM>, sometimes referred to as a "helihoist", is cantilevered off the aft end of the nacelle <NUM>. The floor <NUM> of the service platform <NUM> may be generally L-shaped, when seen from above, having a leg portion <NUM> and a foot portion <NUM>. The service platform <NUM> may have a mesh floor <NUM>. It may have a mesh railing <NUM> extending around the periphery of the service platform <NUM>, preferably, around its entire periphery. A gate <NUM> may be included in the mesh railing <NUM>, preferably adjacent a rear wall <NUM> of the nacelle <NUM>. The gate <NUM> may face an open area <NUM> between the foot portion <NUM> of the service platform <NUM> and the rear wall <NUM> of the nacelle <NUM>. The gate may serve one or more purpose to be described below. The rear wall <NUM> of the nacelle <NUM> preferably has an access door <NUM> providing a means of ingress and egress to the nacelle <NUM> for workers and equipment, especially between the nacelle <NUM> and the platform <NUM>. The nacelle <NUM> has an internal service floor <NUM> (e.g., see <FIG> and <FIG>) that is preferably approximately coplanar with the floor <NUM> of the service platform <NUM>, to facilitate such ingress and egress.

The nacelle <NUM> has a frame <NUM> (either an exoskeleton frame or an endoskeleton frame) that includes dedicated transport fittings <NUM>, for example tangs, ears, or lugs, on the aft end of the nacelle <NUM>. The transport fittings <NUM> shown in the drawings are shown by way of example in the form tangs <NUM>. The service platform <NUM> has a pair of trusses <NUM>, one on each lateral side of the forward end of the service platform <NUM>. Each truss <NUM> may comprise a generally upright post <NUM> and a lateral arm <NUM>. Preferably, the trusses <NUM> may have a generally upright L-shape when seen from the side. The trusses <NUM> connect the platform <NUM> to the nacelle <NUM>. The trusses <NUM> thereby support the platform <NUM>. When connected to the nacelle <NUM>, the arms <NUM> of the L-shaped trusses <NUM> protrude in a direction away from the nacelle <NUM>. The platform <NUM> is thereby supported aft of the nacelle <NUM> in such a way that it forms an extension of the nacelle <NUM> in a direction of the length of the nacelle <NUM>, i.e. in what corresponds to the wind direction. Each truss <NUM> preferably has an upright post <NUM> and a transverse arm <NUM> which may comprise one or more generally lateral struts <NUM>, <NUM>, <NUM>. An upright post <NUM> may be a vertical post <NUM>. An arm <NUM> may be a generally horizontal arm <NUM> although one or more struts <NUM>, <NUM>, <NUM> may extend in a direction which defines an elevation angle to the arm <NUM>. Alternatively or additionally, one or more struts <NUM>, <NUM>, <NUM> may extend in a direction which defines an declination angle to the arm <NUM>. As illustrated, one strut <NUM> defines an elevation angle to the arm <NUM> while another strut <NUM> defines a declination angle to the arm <NUM>. Still another strut <NUM> defines a generally horizontal direction of the arm <NUM>. The floor <NUM> of the service platform <NUM> is predominantly supported on the arm, i.e. on said one or more lateral struts <NUM>, <NUM>, <NUM>. The lateral arm of each truss <NUM> in turn is supported on an upright post <NUM>. As illustrated, the struts <NUM>, <NUM>, <NUM> of a lateral arm of each truss <NUM> are supported on an upright post <NUM>. Preferably, the platform floor <NUM> is thereby supported between a pair of trusses <NUM>. Optionally, a support beam (not shown) may extend between two trusses <NUM>. For example, a support beam may extend between the respective lateral arms of two trusses <NUM>. Such a support beam may extend between one or more of the respective lateral struts <NUM>, <NUM>, <NUM> of two trusses <NUM>. Such a support beam may extend between the respective lateral arms of two trusses <NUM> and beneath the platform floor <NUM>. A support beam between two lateral arms of respective trusses <NUM> may thereby provide additional support or rigidity to the platform <NUM> construction. The tangs <NUM> and posts <NUM> may have respective holes <NUM>, <NUM> through which pins or bolts <NUM> can be inserted to mount the service platform <NUM> to the nacelle <NUM>. In embodiments, the tangs <NUM> may be in the form of so-called corner castings, e.g. ISO type corner castings. The posts <NUM> may also be provided with corresponding corner castings or the posts <NUM> may be provided such that they are connectable to corner castings. For example, holes <NUM> may be corner casting holes, and the posts <NUM> may be connected to corner casting type tangs <NUM> using connectors <NUM> in the form of e.g. ISO type twistlock elements. Accordingly, the connection between the platform <NUM> and the nacelle <NUM> could be via corner castings on the nacelle <NUM>, and using twistlock connectors <NUM> between the nacelle <NUM> and the platform <NUM>.

An electrical outlet <NUM> may be provided, e.g. mounted on the rear wall <NUM> of the nacelle <NUM>, to provide a source of electrical power accessible to the service platform <NUM>.

<FIG> illustrates an example of a service platform <NUM> prior to assembly onto the nacelle <NUM>. <FIG> illustrates a service platform <NUM> after assembly onto the nacelle <NUM>. As illustrated, the service platform <NUM> is preferably assembled onto the nacelle <NUM> after the nacelle <NUM> is installed on the tower <NUM> at the installation site. However, it will be appreciated that the service platform <NUM> could just as well be assembled onto the nacelle <NUM> on the ground, first, and then the assembly of nacelle <NUM> and service platform <NUM> could be lifted up and installed, as a single unit, on the tower <NUM> at the installation site. Techniques for lifting the various wind turbine generator components, to include nacelle <NUM>, rotor hub <NUM>, rotor blades <NUM>, gearbox, transformer, main shaft, main shaft bearing, etc., for assembly onto the tower <NUM> are well known to those skilled in the art and include the use of air ships, cranes (including self-hoisting cranes), helicopters, and the like.

Referring now to <FIG> and <FIG>, and in conjunction with the prior description of <FIG>, <FIG>, <FIG>, and <FIG>, it will be seen that the dedicated fittings, for example tangs, ears, or lugs <NUM> on the nacelle <NUM> serve a dual purpose: one, to attach the nacelle <NUM> (utilizing the tangs <NUM> on the forward and aft ends of the nacelle <NUM>) to first and second transport trailers <NUM> towed by tow vehicle <NUM>, and two, to attach the service platform <NUM> to the nacelle <NUM> (utilizing the tangs <NUM> on the aft end of the nacelle <NUM>). The fittings <NUM> or tangs <NUM> may thus be referred to as nacelle transport tangs <NUM>. More particularly, each transport trailer <NUM> includes a transport frame <NUM> raiseable and lowerable via a lifter, for example hydraulic cylinder <NUM>, operable between the transport frame <NUM> and a bed <NUM> of the transport trailer <NUM>. Each transport frame <NUM> includes fittings, for example tangs, ears, or lugs <NUM> each with a hole <NUM> therethrough that, when aligned with holes <NUM> in tangs <NUM> on a respective end of the nacelle <NUM>, can accept connectors <NUM> e.g. in the form of pins or bolts to secure the nacelle <NUM> to the transport trailers <NUM>. Once so secured (<FIG>), the lifters <NUM> can be energized to lift the nacelle <NUM> up off the ground or up off a supporting structure, for transport to the installation site (<FIG>). Additional details of a similar transport solution can be seen with reference to the assignee's <CIT>, hereby incorporated by reference herein as if fully set forth in its entirety. In contrast to previously suggested transport methods or nacelles, the present disclosure envisages dual-purpose transport tangs <NUM> which, after transportation and delivery of a nacelle <NUM>, e.g. to a construction site, using the transport tangs <NUM>, are subsequently used as connection and support tangs <NUM> for a service platform <NUM> of the nacelle <NUM>. Therefore, according to method aspects of the present disclosure, it is envisaged to transport a nacelle <NUM> between two trailers <NUM> each equipped with a transport frame <NUM> on which the nacelle <NUM> is supported by its transport tangs <NUM>. Thereafter, - e.g. following delivery of the nacelle <NUM> to a delivery site, which may preferably or optionally be a wind turbine construction site - the nacelle <NUM> is disconnected from the transport trailers <NUM> and transport frames <NUM>. Following this, the support trusses <NUM> of a service platform <NUM> are connected to the transport tangs <NUM> which are aft of the nacelle <NUM>. The trusses <NUM> form a cantilever arrangement by which the platform <NUM> is supported. When in position at a nacelle <NUM>, the service platform <NUM> is thereby supported primarily on the transport fittings <NUM> of the nacelle <NUM>.

Referring now to <FIG> and <FIG>, the nacelle <NUM> can include a hoist <NUM>. The hoist <NUM> may be configured to extend through the access door <NUM> in the rear wall <NUM> of the nacelle <NUM>. The hoist <NUM> can thereby be used to transfer a load <NUM> horizontally from the service platform <NUM> into the nacelle <NUM> (<FIG>). The hoist <NUM> can also be configured to be slewed such that a load <NUM> can be transferred vertically upwardly from the ground. The load <NUM> can for example be brought up through the open area <NUM> between the foot portion of the service platform <NUM> and the rear wall <NUM> of the nacelle. Once the load <NUM> has cleared the level of the floor <NUM>, the load <NUM> can be transferred horizontally, e.g. through the gate <NUM> in the mesh railing <NUM>, onto the floor <NUM>. To accomplish these manoeuvres, the hoist <NUM> can have a hoist arm <NUM> pivotally connected to a hoist base <NUM>, and a lifter, for example a hydraulic cylinder <NUM>, operable between the hoist arm <NUM> and the hoist base <NUM>. The base <NUM> can be pivotable about a generally vertical axis to provide the slewing motion. Various means <NUM> known to those skilled in the art can be utilized to provide movement of the hoist <NUM> out of the nacelle <NUM> onto the service platform <NUM>, such as rails, tracks, sliding or rolling floor sections, and the like.

In another aspect of the present invention, the service platform <NUM> can also function as a convenient emergency evacuation platform in the event that workers need to rapidly egress from the nacelle <NUM> for rescue by air ship, crane, helicopter, or the like. For example, should a fire or other event occur in the nacelle <NUM> that requires a quick evacuation of personnel, the access door <NUM> in the rear wall <NUM> may be opened such that personnel can escape to the service platform <NUM>. In addition to being evacuated from the service platform by air, the service platform <NUM> may contain other equipment, such as various chutes or escape pods (not shown), that allow personnel to evacuate from the nacelle <NUM> to the ground or platform adjacent the base of the tower <NUM>.

The nacelle and service platform of the present invention thus conveniently permit personnel and equipment to be either vertically lifted or lowered onto the service platform and then transferred horizontally from the service platform into the nacelle via the door in the rear wall of the nacelle. Personnel and equipment can be placed on the service platform with air ships, cranes (including self-hoisting cranes), helicopters, etc. The equipment can then be transferred horizontally from the service platform through the door in the rear wall of the nacelle and into the nacelle via the nacelle hoist. Personnel can simply walk from the service platform through the door in the rear wall of the nacelle and into the nacelle. Personnel and equipment are thus not required to be lowered down into the nacelle through a hatch in the top of the nacelle. And, the dedicated fittings of the nacelle or nacelle frame provide a convenient means of both transporting the nacelle as well as mounting the service platform on the nacelle.

Claim 1:
A wind turbine generator nacelle (<NUM>), comprising:
a nacelle frame (<NUM>) having a first forward hub end and a second aft end;
dedicated transport fittings (<NUM>) at each of said ends of said nacelle frame (<NUM>), said fittings (<NUM>) adapted to be engaged by transport frames (<NUM>) on first and second transport trailers (<NUM>) for supporting said nacelle frame (<NUM>) for transport by the trailers (<NUM>); and
a service platform (<NUM>) mounted to said transport fittings (<NUM>) on said aft end of said nacelle frame (<NUM>) such that said service platform (<NUM>) is cantilevered off of said aft end of said nacelle frame (<NUM>), wherein said nacelle (<NUM>) has an internal service floor (<NUM>) and wherein a floor (<NUM>) of said service platform (<NUM>) is substantially coplanar with said internal service floor (<NUM>).