EP3613695A1

EP3613695A1 - Elevator systems

Info

Publication number: EP3613695A1
Application number: EP18382622.1A
Authority: EP
Inventors: Marta Pastor García
Original assignee: Alimak Group Management AB
Current assignee: Alimak Group Management AB
Priority date: 2018-08-21
Filing date: 2018-08-21
Publication date: 2020-02-26

Abstract

An elevator system for a wind turbine tower is provided. The elevator system comprises an elevator cabin configured to perform an up and down movement along an elevator path. The elevator path comprises a wall and an evacuation structure is attached to the wall. The elevator system further comprises a security structure pivotally mounted to the elevator cabin between a rest position in which the security structure is stowed with the elevator cabin and the elevator cabin is able to perform the up and down movement along the elevator path and an operational position in which the security structure is arranged so as to span over a distance between the elevator cabin and the evacuation structure.

Description

The present disclosure relates to elevator systems, for example, service elevator systems configured for use in wind turbine towers. The present disclosure further relates to wind turbines comprising such elevator systems.

BACKGROUND

Modern wind turbines are commonly used to supply electricity into the electrical grid. Wind turbines generally comprise a rotor with a rotor hub and a plurality of blades. The rotor is set into rotation under the influence of the wind on the blades. The rotation of the rotor shaft drives the generator rotor either directly ("directly driven") or through the use of a gearbox. The operation of the generator produces the electricity to be supplied into the electrical grid.
When maintenance works are required inside wind turbines, hoists are often used in the form of elevator-like structures where a lift platform or a cabin for the transportation of people and/or equipment is hoisted up and down within the wind turbine tower. Wind turbines are often provided with working platforms arranged at various altitudes along the height of the tower with the purpose of allowing workers to leave the cabin and inspect or repair equipment where intended or needed. These sorts of elevator systems are also known in other applications, such as e.g. factories, construction sites, and all sorts of towers.
Elevator systems in general include an elevator car or cabin that is suspended within a hoistway or elevator shaft by wire ropes or any other relatively thick cable. The elevator cabin may be suspended by a traction wire rope. Service lifts can be hoisted up and down along the traction wire rope by means of a traction device. In other examples, an elevator cabin may have a rack-and-pinion driving mechanism. To facilitate maintenance and inspection works inside the elevator system, the elevator paths are usually provided with a ladder fixed to its inner walls.
In use, there may be circumstances in which the elevator cabin needs to be evacuated. The ladder fixed to the inner walls of the elevator path may serve for cabin evacuation purposes. For example, to help the personnel travelling in the cabin to leave the cabin in case of a sudden stop or any other mishap that does not allow the cabin to move to e.g. a working platform. In these situations, the personnel may use personnel protective equipment (PPE) in order to ensure a relatively safe climb when leaving the cabin and moving along the ladder. However, this type of equipment merely serves to reduce exposure to hazards and/or reduce risks to acceptable levels, but they do not eliminate the hazard.
Similarly, if an elevator cabin is stopped somewhere between platforms, personnel may need to recover the elevator cabin by going up the ladder and accessing the elevator cabin from the ladder. Personnel protective equipment may be used in this case as well to reduce the risk of falling or personal injury during this sort of operation.
Wind turbines are high slender structures that are usually supported by a closed tower. Wind turbine towers sometimes involve curved elevator paths, e.g. because at the base there may be an electronic compartment on one side or because the available space for housing the elevator requires a change in the orientation. Also very usual in wind turbine towers is to provide major or minor tapering of the tower e.g. due to a change of the material from which the tower is built. For example, a bottom portion of a tower may be made e.g. from concrete and an upper portion of the tower may be made e.g. from steel. In these situations a distance from the elevator cabin to the inner walls of the tower (elevator path) may also vary from one section to the other.
An average walking stride length for men is approximately 78 - 80 cm long whereas for women the average walking stride length is approximately 70 cm. This means that a single stride of up to about 70 or 80 cm could be done in a relatively easy and safe manner by somebody of average height needing to reach e.g. a ladder fixed to the inner wall of an elevator path from the elevator cabin. For this reason, some wind turbine manufacturers require a maximum distance between the elevator cabin and the evacuation structure of 70 centimetres. This however is not always possible depending on the shape of the tower and the elevator path. International safety standards in some cases also define a maximum distance. For example a US safety standard for wind turbines defines a maximum distance of 1,1 metres.
Depending on the elevator path, it is possible that along stretches of the elevator path, a distance between the elevator cabin and the ladder is more than 70 or 80 cm, or more than 1 meter, and sometimes more than 1,20 metres. An increased distance between the elevator cabin and the ladder means an increased risk during the procedures for accessing or evacuating the elevator cabin.
As such there is a need for reliable and effective elevator systems that are able to reduce or eliminate at least some of the afore-mentioned drawbacks, even when abrupt changes are present in the elevator path.

SUMMARY

In accordance with a first aspect, an elevator system is provided. The elevator system comprises an elevator cabin configured to perform an up and down movement along an elevator path. The elevator path comprises a wall and an evacuation structure. The elevator system further comprises a security structure mounted to the elevator cabin configured to assume a rest position in which the security structure is stowed with the elevator cabin and the elevator cabin is able to perform the up and down movement along the elevator path and to assume an operational position in which the security structure is arranged so as to span over a distance between the elevator cabin and the evacuation structure.
Throughout the present description and claims, an elevator path is to be understood as a space or passage through which the elevator can travel upwards and downwards. For example, in a wind turbine tower, the elevator path is defined inside the wind turbine tower, i.e. a closed space inside the tower along which the elevator cabin travels.
According to this aspect, a security structure is provided at the elevator cabin. The security structure is able to adopt two different positions. A first position is the rest position in which the elevator cabin is able to perform its up and down movement, i.e. in which the security structure does not hinder such an up and down movement of the elevator cabin. In the rest position, the security structure does not significantly affect the outer dimensions or perimeter of the elevator cabin such that the cabin does not enter into contact with platforms, tower flanges, or other components.
In addition, the security structure is able to adopt the operational position in which the security structure spans over a distance between the elevator cabin and the inner wall of the elevator path. In the operational position, the security structure thus provides for a distance reducing element/structure on which a person willing to reach the inner wall of the elevator path can step on. The security structure, when in the operational position, may act as e.g. a platform on which personnel trying to leave the elevator cabin can step on in its way to e.g. an evacuation ladder that may be provided at the inner wall of the elevator path.
Elevator systems substantially as hereinbefore described may be adapted or configured for a particular application, such as e.g. a wind turbine tower. As explained above, wind turbine towers sometimes involve curved elevator paths. Elevators substantially as hereinbefore described are particularly suitable for such curved elevator paths as on one hand the security structure does not hinder the up and down movement of the elevator cabin, and on the second hand, if needed a structure may be deployed (rotated) to provide a structure covering the distance from the cabin to the inner wall of the elevator path.
In some examples, the distance between the elevator cabin and the evacuation structure along at least a portion of the up and down movement of the elevator cabin may be at least approximately 80 cm, particularly at least 1 meter long.
However strides over 70 or 80 cm or over 1 meter long may encompass a reasonable vertigo and/or risk of falling for personnel needing evacuation from the elevator cabin. Such risks may be avoided or at least reduced by providing a structure able to cover or reduce such a distance substantially as hereinbefore described.
A security structure substantially as hereinbefore described is relatively simple to implement and can be retrofitted in existing elevator systems having an elevator cabin configured to perform an up and down movement along an elevator path, the elevator path comprising an inner wall. Security structures as herein described are particularly suitable for elevator systems running along curved elevator paths in which the distance between the elevator cabin and the inner wall of the elevator path may vary substantially from one section of the elevator path to another section of the elevator path.
A further aspect provides for a wind turbine comprising an elevator system substantially as hereinbefore described arranged within a wind turbine tower.

BRIEF DESCRIPTION OF THE DRAWINGS

Non-limiting examples of the present disclosure will be described in the following, with reference to the appended drawings, in which:

Figure 1 and 2 show perspective views of an elevator system according to an example in two different operational positions of the security structure; and
Figures 3 and 4 show plan views respectively of the examples shown in figures 1 and 2.

DETAILED DESCRIPTION OF EXAMPLES

In these figures the same reference signs have been used to designate matching elements.
Figure 1 and 2 show perspective views of an elevator system according to an example in two different operational positions of its security structure. Figure 1 shows the security structure in a resting position and figure 2 shows the security structure in an operational position. Figures 3 and 4 show schematic plan views of the examples shown in figures 1 and 2, particularly shown from above a working platform 20.
The elevator system comprises an elevator cabin 1 which may be moved up and down along an elevator path (see arrow A) e.g. by a traction wire rope 2. The elevator cabin can be hoisted up and down along the traction wire rope by means of a traction device (not shown) mounted on or attached to the elevator cabin. The traction device may comprise a housing including a traction mechanism, e.g. a motor driven traction sheave. The motor typically may be an electrical motor, although in principle other motors could be used.
A safety wire rope may further be provided. A fall-arrest device may be mounted on the safety wire rope and the fall-arrest device can automatically block the elevator cabin and inhibit any further movement if the elevator cabin moves too fast, i.e. when the elevator cabin might be falling.
In alternatives, more than one traction wire ropes and/or security wire ropes may be foreseen. In more examples, the elevator cabin may be driven by other driving means such as e.g. a rack and pinion engagement.
The elevator path may be defined inside a substantially slender tower, particularly a wind turbine tower that in some examples may comprise different tower sections having different diameters thereby rendering a substantially curved elevator path. As further shown in these figures, an inner wall 10 of the wind turbine tower comprises a maintenance or evacuation ladder 11. In other examples, the maintenance or evacuation ladder may be removably attached to the inner wall, e.g. only when needed. Any suitable evacuation structure may be used. A suitable evacuation structure may typically include a plurality of steps or rungs. Such an evacuation structure or ladder may be used for climbing up and down and may thus be used in case the elevator cabin needs to be abandoned and personnel inside the cabin needs to climb down. But the same structure may also be used by personnel to climb up and recover the elevator cabin.
In this example, a security ladder 3 is pivotally mounted to a side 101 of the elevator cabin 1 that in use faces the evacuation ladder 11 that may be provided at the inner wall 10 of the elevator path. The security ladder 3 may thus operate varying between two well-defined positions or "states": a) a rest position (see figures 1 or 3) in which the security ladder 3 lays adjacent or "is stowed" or just pivoted towards the side 101 of the elevator cabin 1 thereby allowing the elevator cabin 1 to perform its up and down movement along the elevator path (see arrow A); and b) an operational position (see figures 2 and 4) in which the security ladder 3 is unfolded/deployed or pivoted away from the cabin's side and spans a distance between the elevator cabin 1 and the evacuation ladder 11.
According to the example shown in figures 1 and 2, the security ladder 3 comprises six transverse elements 31 or rungs arranged between two vertical rods 32 or side pieces. Around one of these two vertical rods, the security ladder may pivot, particularly the vertical rod arranged proximally to the elevator cabin.
In this particular example, the hinge point or hinge axis is arranged in proximity of the front access of the elevator cabin. When the security ladder is pivoted towards the operational position, the security ladder is thus arranged so that it can be reached and accessed from the elevator cabin.
In alternative examples other numbers of rungs or transverse elements including a single rung may be foreseen. In those examples comprising a single rung, the rung may be provided between a vertical rod provided at the rungs' proximal end (i.e. closer the elevator cabin) and around which the security structure pivots, and an angled link or tensioner extending between a rung's distal end (i.e. further away from the elevator cabin) and the proximal vertical rod. This provides for a rather simple construction.
As schematically shown in figure 3, the security ladder 3 (or other type of security structure) may be designed such that it does not hinder other additional equipment or elements that may be present at the side of the elevator cabin. For example, in case of an elevator cabin being guided by a pair of taut cables running laterally from the elevator cabin, the security structure is configured such that it does not hinder these cables or its guide wires when it lays adjacent or folded over the side of the elevator cabin.
Figures 3 and 4 further show two tower sections 41, 42 having different diameters. This represents at least one abrupt change in the curvature of the inner wall thereby in the elevator path. In alternatives, other numbers and other shapes of tower sections may be foreseen.
In some examples a transverse element or rung may be aligned with a floor of the elevator cabin. This reduces vertigo and/or risk of falling for personnel needing evacuation.
In examples, end portions of the transverse elements, particularly distal ends thereof, may be provided with extensions. The extensions may be foldable, removable, telescopic or retractable according to circumstances. The extensions provides for more versatile security structures. This implies that in circumstances the transverse elements may be extended or may cover even longer distances, e.g., in a specific case of an abrupt change in curved path of the elevator cabin.
In examples, elevator systems substantially as hereinbefore described may further comprise a security switch configured to prevent the up and down movement of the elevator cabin when the security structure is in the operational position. This way, when the security structure is deployed (i.e. it is in the operational position), the security switch automatically cuts off e.g. the motor power. For example, such a switch may interrupt the power circuit of the elevator system at the moment that the security structure is deployed from the rest position towards the operational position.
In more examples, the security structure may further comprise a (e.g. mechanical) locking system configured to lock the security structure in the operational position and/or in the rest position thereby enhancing safety of the evacuation structure. Only a conscious action undertaken by personnel can therefore serve to change between the operational position and the rest position. Vibrations that might occur in the elevator cabin as it moves up and down cannot cause the security structure to inadvertently deploy. In some examples, the security structure may be prevented from deploying unless the power for driving the elevator cabin up or down is cut off.
Although in the specific example described herein, the security structure is a ladder and the mechanism for changing between an operational position and a rest position is a pivoting mechanism, other security structures and mechanisms might be used.
In yet further examples, a security structure instead of being pivoted may be unfolded. E.g. a security ladder with foldable rungs and/or foldable guardrails might be envisaged.
In yet further examples, a security structure might be pivoted away from the stowed position and unfolded to reach an operational position. In further examples, a security structure might undergo two pivoting actions (e.g. about perpendicular pivoting axes) to change between an operational position and a rest position. A substantially flat support, plate or platform might in a rest position be arranged vertically and substantially flush with the sidewall of the elevator cabin similar to what is shown in figure 1. Such a security structure might be pivoted around a vertical axis to reach an intermediate position closer to the front of the elevator cabin and pivoted around a horizontal axis to that the security structure reaches a substantially horizontal operational position. Personnel might easily step on the platform in this operational position and the distance to the evacuation structure is reduced. It should be clear that the order of pivoting about the different axes might be changed as well.
Furthermore, a security structure substantially as hereinbefore described is relatively simple to implement. It can therefore be easily retrofitted into existing elevator systems having an elevator cabin configured to perform an up and down movement along an elevator path. Particularly in those elevator systems comprising an evacuation ladder attached to an inner wall of the elevator path.
In that sense, a method for retrofitting an elevator system comprising an elevator cabin configured to perform an up and down movement along an elevator path comprising an inner wall may be provided. The method comprises (pivotally) mounting a security structure substantially as hereinbefore described to a side of the elevator cabin such that the security structure is able to adopt two positions: a rest position in which the security structure lays adjacent the side of the elevator cabin (or "flush" with a sidewall of the elevator cabin) and the elevator cabin is able to perform the up and down movement along the elevator path; and an operating or deployed position in which the security structure is rotated so as to span over a distance between the elevator cabin and the inner wall of the elevator path.
According to these methods, existing elevator systems may be retrofitted to add the additional functionalities substantially as hereinbefore described.
Although the examples disclosed herein to an elevator system inside a wind turbine tower, it should be clear that similar elevator systems have different applications in buildings, construction sites and other.
Although only a number of examples have been disclosed herein, other alternatives, modifications, uses and/or equivalents thereof are possible. Furthermore, all possible combinations of the described examples are also covered. Thus, the scope of the present disclosure should not be limited by particular examples, but should be determined only by a fair reading of the claims that follow.

Claims

An elevator system comprising:
an elevator cabin configured to perform an up and down movement along an elevator path, the elevator path comprising a wall and an evacuation structure, wherein the elevator system further comprises

a security structure configured to assume a rest position and an operational position,

wherein in the rest position, the security structure is stowed with the elevator cabin and the elevator cabin is able to perform the up and down movement along the elevator path and

in the operational position, the security structure is arranged so as to span over a distance between the elevator cabin and the evacuation structure.
The elevator system of claim 1, wherein the distance between the elevator cabin and the evacuation structure along at least a portion of the up and down movement of the elevator cabin is at least 1 meter, specifically over 1,2 meters.
The elevator system of claim 1 or 2, wherein the security structure is pivotally mounted to the elevator cabin and is configured to pivot between the rest position and the operational piston.
The elevator system according to any of claims 1 - 3, wherein the structure is foldable and is configured to fold and unfold between the rest position and the operational position.
The elevator system of any of claims 1 - 4, wherein the security structure comprises one or more transverse elements transversally arranged with respect to the up and down movement of the elevator cabin.
The elevator system of claim 5, wherein in the rest position the transverse elements lay flush with a sidewall of the elevator cabin and in the operational position the transverse elements extend away from the elevator cabin, particularly substantially aligned with a door of the elevator cabin.
The elevator system of claim 5 or 6, wherein one of the transverse elements is arranged substantially aligned with a floor of the elevator cabin.
The elevator system of any of claims 5 - 7, wherein the transverse elements are arranged between two vertical rods, and optionally wherein the security structure is a security ladder.
The elevator system of any of claims 5 - 7, wherein the transverse element is arranged between a vertical rod provided at a proximal end of the transverse element and an link/tensioner extending between a distal end of the transverse element and the vertical rod.
The elevator system of any of claims -5 - 7, wherein the transverse element is a platform, the platform being configured to pivot around two perpendicular axes.
The elevator system of any of claims 1 - 10, wherein the elevator system further comprises a security switch configured to prevent the up and down movement of the elevator cabin when the security structure is in the operational position.
The elevator system of any of claims 1 - 11, wherein the security structure is mounted to a side of the elevator cabin.
The elevator system of any of claims 1 - 12, wherein the evacuation structure is an evacuation ladder.
The elevator system of any of claims 1 - 13, wherein the security structure further comprises a locking system configured to lock the security structure in the operational position, and optionally wherein the security structure comprises a locking system configured to lock the security structure in the rest position.
A wind turbine comprising an elevator system according to any of claims 1 - 14 arranged within a wind turbine tower.