Tilting rotating sail

Abstract

The invention relates to a rotary sail (100) extending in a vertical direction around an axis of rotation (110) comprising: a lower section (101) comprising a lower aerodynamic surface (121) linked to a rotational drive means; an upper section (102) comprising an upper aerodynamic surface (122) linked continuously to the lower aerodynamic surface (121) by disconnectable connecting means (125, 321, 322); and tilting means (250) comprising a pivot connection (150) along an axis of a direction secant to the vertical direction, between the lower section (101) and the upper section (102) at a height h (15) measured from the base (30), configured so that when the disconnectable connection means (125, 321, 322) are disconnected, the upper section (102) is able to pivot around the pivot connection (150) relative to the lower section (101).

Description

Title of the invention: Tilting rotary sail Technical field

[0001] The invention belongs to the field of sail propulsion, more particularly the invention relates to a Flettner type rotary sail, suitable for the propulsion of a ship, in main propulsion mode or in assistance of another propulsion mode. Prior art

[0002] Sail propulsion, whether as primary propulsion or as assistance, is a way of reducing the carbon footprint of maritime transport.

[0003] Among the means of sail propulsion envisaged for this type of application, Flettner type rotary sails, using the Magnus effect, are interesting because they make it possible to generate a sail thrust force in a wider range of wind conditions, without the need to orient the sail and with reduced bulk compared to a flexible sail.

[0004] However, the addition of these riggings, the height of which can exceed 50 m from the deck of the ship, is not without posing difficulties, particularly for crossing bridges when passing through estuaries, or with regard to port installations. The windage of the rotary sail and therefore its impact on the consumption of the ship when sailing in a headwind or on the stability of the ship when sailing in strong winds are also factors limiting the acceptable size of rotary sails.

[0005] While flexible sails can be lowered and the masts carrying these sails inclined so as to limit their height, in the case of a Flettner type rotary sail such an operation is significantly more complex due to the weight of the sail and the presence of the devices for driving and guiding the rotary sail in rotation.

[0006] Document US 4,401,284 describes an inflatable rotary rigging, this type of device is difficult to adapt to rotary sails whose dimensions are related to the propulsion needs of the ships covered by the invention.

[0007] Document US 4,602,584 describes a ship provided with a Flettner type rotary sail, comprising at its base, substantially at the level of the ship's deck, a hinge mechanism for lowering the rotary sail by tilting it onto the deck. This type of mechanism is also difficult to adapt to large rotary sails whose weight reaches several tens of tons; it also requires shrouds to hold the rotary sail in its position, which clutter up the deck. Summary of the invention

[0008] The invention aims to resolve the drawbacks of the prior art and relates to this end to a rotating sail extending in a vertical direction over a height H measured from a base, around an axis of rotation, configured to rotate around this axis of rotation, comprising:

[0009] a lower section comprising a lower aerodynamic surface linked to a rotational drive means;

[0010] an upper section comprising an upper aerodynamic surface continuously connected to the lower aerodynamic surface by disconnectable connecting means; and

[0011] tilting means comprising a pivot connection along an axis of a direction secant to the vertical direction, between the lower section and the upper section at a height h measured from the base, configured so that when the disconnectable connection means are disconnected, the upper section is able to pivot around the pivot connection relative to the lower section (101).

[0012] Thus, the upper section of the rotating sail can be tilted around the pivot connection at height h so as to reduce the height of the sail.

[0013] The invention is implemented according to the embodiments and variants set out below which are to be considered individually or according to any technically operative combination.

[0014] The height h is preferably greater than or equal to a height H / 2., which makes it possible to tilt the upper section by a tilt angle of the order of 180° relative to the lower section.

[0015] Advantageously, the lower section comprises an inner tower extending from the base over a height less than or equal to the height h. This configuration makes it possible to concentrate the weight of the rotating sail mainly in the lower section and to reduce the weight of the upper section to facilitate tilting maneuvers.

[0016] According to alternative embodiments, the tower is fixed and the lower aerodynamic surface is guided in rotation around the tower or the rotation drive means is configured to drive the tower in rotation and the lower aerodynamic surface is rotationally linked to the tower.

[0017] Advantageously, the tower is mainly made of a material chosen from wood and a composite comprising wood fibers, likewise, the aerodynamic surfaces comprise an assembly of panels made of a material chosen from wood, a composite material and a canvas. These embodiments make it possible to reduce the weight of the rotating sail while giving it great rigidity, in particular in bending perpendicular to the axis of rotation.

[0018] Advantageously, the tilting means comprise a tilting device configured so that the upper section is moved in the vertical direction. before its pivoting around the axis of the pivot connection. This embodiment makes it possible to disconnect the centering and connection means between the lower section and the upper section via the tilting kinematics imposed by the tilting device.

[0019] According to one embodiment, the tilting device is configured such that the axis of the pivot connection moves from inside an envelope diameter of the lower section to outside the envelope diameter of the lower section during tilting of the upper section relative to the lower section.

[0020] Advantageously, the tilting device is configured to tilt the upper section relative to the lower section by a tilting angle of at least 90° and preferably the maximum tilting angle of the upper section relative to the lower section is greater than 160°.

[0021] Advantageously, the rotating sail comprises a device for balancing the rotation of the upper section.

[0022] According to one embodiment, the rotational balancing device comprises a plurality of masses and means for controlling the radial position of each net of the plurality.

[0023] According to another embodiment, which can be combined with the previous one, the rotation balancing device comprises a plurality of weights and means for moving each weight along an inner circumference of the upper section. Brief description of the drawings

[0024] The invention is implemented according to the preferred embodiments, which are in no way limiting, set out below with reference to [Fig.1] to [Fig.7] in which: Fig.l

[0025] [Fig.l] shows in a front view in partial section an example of the principle of a rotary sail provided with a tilting mechanism; Fig.2

[0026] [Fig.2] is a partial sectional view of an exemplary embodiment of a rotary sail whose two sections are aligned Fig. 3

[0027] [Fig.3] shows in partial view, the rotating sail of [Fig.2] in which the section upper section is tilted at a tilt angle of around 90° relative to the lower section; Fig.4

[0028] [Fig.4] shows in partial view, the rotating sail of [Fig.2] in which the section upper is tilted by a tilt angle of the order of 170° relative to the lower section; Fig.5

[0029] [Fig.5] shows in a perspective view from above a first example of a sheave use of a rotation balancing device for the upper section of the rotating sail; Fig.6

[0030] [Fig.6] shows a second example of the embodiment of a balancing device in rotation of the upper section of the rotary sail. Fig.7

[0031] [Fig.7] shows a schematic front view of an example of an embodiment of the rotating sail including a balance control device. Description of the embodiments

[0032] [Fig.l] according to an exemplary embodiment, a rotary sail (100) adapted to the propulsion of a ship, extends according to a height H (10), commonly greater than 50 meters relative to a deck (30) of the ship, according to an external aerodynamic surface (121, 122) substantially cylindrical included in an envelope diameter D (20), greater than 3 meters, commonly greater than 5 meters and greater than or equal to 7 meters. So that a slenderness coefficient defined by a ratio H / D is between 5 and 10, commonly between 5 and 8.

[0033] The term "cylindrical" is not limited to a straight cylinder of constant diameter over its height.

[0034] The weight of such a rotating sail is a few dozen tons, commonly 30 to 50 tons. Consequently, tilting and then returning the entire rotating sail to a vertical position would require significant means, especially since during the tilting movement it would be subject to its own weight, which would require the installation of auxiliary support means such as shrouds and controlled winches.

[0035] In use, that is to say to provide a propulsion force capable of moving the ship forward, the sail is rotated about a vertical axis (110) at a rotation speed such that the tangential speed to the external aerodynamic surface (121, 122) is of the order of or greater than 2 times the speed of a wind to which the sail is subjected, which leads to rotation speeds commonly between 100 and 300 revolutions / minute, commonly between 100 and 200 revolutions / minute and most often between 100 and 150 revolutions / minute.

[0036] The sail comprises inside the aerodynamic surface a tower (131, 132) which ensures its vertical rigidity and the transmission of the sail thrust force to the ship.

[0037] The aerodynamic surface (121) is, at least on a section called the lower section (101), connected by ferrules (140) to the tower (131, 132). According to an exemplary embodiment, the tower (131, 132) is made of wood or a material comprising wood fibers.

[0038] On a second section of the rotating sail, called the upper section (102), the aerodynamic surface (122) is linked in rotation to the lower section, for example via an appropriate interface (125) implementing complementary shapes, without being connected to the tower (131, 132).

[0039] According to one embodiment, the tower (131, 132) is fixed and the aerodynamic surface (121, 122) is driven in rotation around the vertical axis (110) by appropriate means and guided in rotation around the tower. In this case the ferrules (140) are bearings implementing means for guiding rotation around the tower, for example bearings (not shown).

[0040] According to another embodiment, the tower is driven in rotation around the vertical axis (110), the ferrules (140) are then means of complete connection between the tower (131, 132) and the aerodynamic surface (121) of the lower section (101).

[0041] The aerodynamic surface (121, 122) is made up, according to exemplary embodiments, of an assembly of lightweight panels made from wood, a composite material with fiber reinforcement, or even stretched canvas. This assembly comprises reinforcement means (not shown), for example in the form of metal hoops or made from composite material at the level of the connections with the tower and at the level of the interface (125) connecting the two sections (101, 102).

[0042] The rotating sail comprises at a height h (15) a pivot connection (150) whose pivot axis extends along an axis other than vertical, and preferably horizontal, linking the upper section (102) to the lower section (101) so that the upper section (102) can tilt relative to the lower section (101) by rotation around this pivot axis.

[0043] Those skilled in the art understand that the tilting around the connection can be achieved by more complex kinematics than simple pivoting and can comprise, for example, a vertical translation of the second section (102) to retract the rotating connection (125) around the vertical axis (110) between the sections before performing the pivoting around the pivot connection (150).

[0044] Since the upper section (102) does not include a rotational connection with the tower and this section is significantly lighter than the lower section, the means necessary for this tilting are significantly simplified compared to tilting the entire rotating sail.

[0045] Thus the weight of the second section (102) is of the order of a few tonnes, typically 5 to 10 tonnes depending on the height h, compared to several tens of tonnes for the entire rotating sail.

[0046] [Fig.2], thus, according to an exemplary embodiment, the tilting mechanism is placed inside the rotating sail.

[0047] For this purpose, the lower section (101) comprises at its top a lower platform (211) and the upper section (102) comprises at its proximal end with the lower section, an upper platform (212). The lower platform (211) is connected in complete connection to the lower aerodynamic surface (121) and the upper platform (212) is connected, in complete connection, to the upper aerodynamic surface (122).

[0048] According to this embodiment, when the lower section and the upper section are coupled with their aerodynamic surfaces (121, 122) in continuity with each other, the tilting device (250) as well as the pivot axis are located inside the envelopes of the upper and lower sections and are not visible from the outside of the rotating sail and thus do not disturb the aerodynamic flows on the surfaces of the sail.

[0049] According to this exemplary embodiment, the tilting device (250) comprises a plurality of connecting rods and is controlled by one or more hydraulic, electric or pneumatic cylinders (251), so that the tilting kinematics produces a vertical translation of the upper section before pivoting around a pivot axis outside the envelope diameter of the lower section.

[0050] Such kinematics makes it possible to decouple and couple centering and rotational drive means between the lower aerodynamic surface (121) and the upper aerodynamic surface (122).

[0051] Thus, according to an exemplary embodiment [Fig. 3] the ends of the upper and lower sections comprise complementary surfaces (321, 322), for example conical, which ensure the centering of the two sections relative to each other and participate in the transmission of the rotational drive other than the vertical axis (110) of the upper section by the lower section.

[0052] As indicated previously, the kinematics imposed by the tilting device (250) allows, during the extension of the jack(s) (251) and by means of the connecting rods, to lift the upper section so as to separate the respective centering surfaces (321, 322) of the lower and upper sections before carrying out the pivoting around a pivot axis external to the external envelope of the lower section.

[0053] A rotation angle of the rotary sail around the vertical axis (110) prior to tilting, while the two sections (101, 102) are still coupled, makes it possible to define the angular position around the vertical axis (110) of the pivot axis of the upper section (102) relative to the lower section and thus to position, for example, the upper section (102) relative to the deck of the ship and around the vertical axis (110).

[0054] [Fig.3] shows a tilting of the order of 90° of the upper section (102) relative to the vertical axis (110) of the lower section (101). In certain circumstances, for example for the passage of a point, such a tilting angle (300), or even lower, may be sufficient.

[0055] [Fig-4] advantageously, the final tilting angle (400) of the upper section, defined relative to the vertical axis (110) of the lower section, is greater than 160°, preferably greater than 170° and close to 180°.

[0056] According to this exemplary embodiment, the tilting angle depends on the displacement imposed by the cylinder (251) of the tilting device (250) and can be controlled by the extension distance of this cylinder.

[0057] Advantageously, this tilting angle can also be measured remotely by any optical means, in particular of the Laser Tracker type. To this end, according to an exemplary embodiment, the lower section and the upper section comprise optical targets (not shown) making it possible to measure the relative position and orientation of the upper section with respect to the lower section. This information is advantageously used to control the cylinder (251) of the tilting device in a servo-controlled manner.

[0058] According to an exemplary embodiment, the upper section comprises one or more rotation balancing devices (422).

[0059] [Fig.5] according to an exemplary embodiment such a balancing device (422i) comprises a plurality of masses (510) and means such as a worm screw (520) driven by a stepping motor (530) for radially and individually moving each mass (510) of the plurality.

[0060] [Fig.6] according to another exemplary embodiment the balancing device (4222) comprises a plurality of weights (610) each movable individually on a toothed crown (620) along an inner circumference of the upper section, by means of a stepping motor (630).

[0061] According to another embodiment (not shown) the balancing device comprises a hollow torus with a diameter equivalent to an internal diameter of the upper section, which hollow torus is filled with a powdery material such as sand.

[0062] These embodiments of the rotation balancing device can be combined on the same section.

[0063] [Fig.7] To this end, the rotary sail comprises a plurality of accelerometers (751, 752, 753, 754) installed, for example, on the envelopes constituting the aerodynamic surfaces (121, 122) of the lower section and the upper section, preferably on the internal face of this envelope so that the accelerometers are relatively protected from the environment.

[0064] Said accelerometers provide a signal proportional to a vibration level, this signal is transmitted, for example via a WiFi® type connection to a computing center (790) with an identifier specific to each accelerometer.

[0065] Said computing center (790) comprises a file defining for each identifier a position of the accelerometer on the rotating sail and a computer program making it possible to determine, from the acquired signals, a balance defect of the rotating sail according to one or more planes.

[0066] Thus, after a tilting and re-alignment maneuver of the upper section of the rotary sail, a balancing cycle is launched consisting of making the rotary sail perform at least one turn, acquiring the signals from the accelerometers, deducing an imbalance and a correction from the computer program of the computing center (190) and applying this correction by acting on the rotating balancing devices.

[0067] Alternatively or in addition to accelerometers, a non-contact measurement, for example by laser interferometry, can also be carried out during the balancing procedure in order to determine the rotational unbalance of the sail.

[0068] The above description and the exemplary embodiments show that the invention achieves the objectives sought, in particular it makes it possible to reduce the height of a large rotary sail by tilting a lightened upper part of this rotary sail, facilitating and accelerating such a maneuver compared to the solutions of the prior art.

Claims

Claims

1. Rotary sail (100) extending in a vertical direction over a height H (10) measured from a base (30), around an axis of rotation (110), configured to rotate around this axis of rotation, comprising: a lower section (101) comprising a lower aerodynamic surface (121) linked to a rotation drive means; an upper section (102) comprising an upper aerodynamic surface (122) linked in continuity to the lower aerodynamic surface (121) by disconnectable connecting means (125, 321, 322);and tilting means (250) comprising a pivot connection (150) along an axis of a direction secant to the vertical direction, between the lower section (101) and the upper section (102) at a height h (15) measured from the base (30), configured so that when the disconnectable connection means (125, 321, 322) are disconnected, the upper section (102) is able to pivot around the pivot connection (150) relative to the lower section (101).;

2. A rotary sail according to claim 1, wherein the height h (15) is greater than or equal to a height H / 2.

3. A rotary sail according to claim 1, wherein the lower section (101) comprises an inner tower (131, 132) extending from the base over a height less than or equal to the height h (15).

4. A rotary sail according to claim 3, wherein the tower (131, 132) is fixed and the lower aerodynamic surface (121) is guided in rotation around the tower.

5. A sail according to claim 3, wherein the rotational drive means is configured to rotate the tower and wherein the lower aerodynamic surface (121) is rotationally linked to the tower.

6. A rotary sail according to claim 3, wherein the tower is predominantly made of a material selected from wood and a composite comprising wood fibers.

7. A rotary sail according to claim 3, wherein the aerodynamic surfaces (121, 122) comprise an assembly of panels made of a material selected from wood, a composite material and a canvas.

8. A rotary sail according to claim 1, wherein the bas-

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14. The assembly comprises a tilting device (250) configured so that the upper section (102) is moved in the vertical direction before pivoting about the axis of the pivot connection. A rotary sail according to claim 8, wherein the tilting device (250) is configured such that the axis of the pivot link moves from inside an envelope diameter (20) of the lower section (101) to outside the envelope diameter of the lower section during tilting of the upper section (102) relative to the lower section (101). A rotary table according to claim 8, wherein the tilting device (250) is configured to tilt the upper section (102) relative to the lower section (101) by a tilting angle (300, 400) of at least 90°. A rotary sail according to claim 10, wherein a maximum tilt angle (400) of the upper section (102), relative to the lower section (101), is greater than 160°. Rotary sail according to claim 1, comprising a balancing device (422) in rotation of the upper section (102). A rotary sail according to claim 12, wherein the rotational balancing device comprises a plurality of masses (510) and means (520, 530) for controlling the radial position of each of the plurality. A rotary sail according to claim 12, wherein the rotational balancing device comprises a plurality of weights (610) and means (630) for moving each weight along an inner circumference of the upper section.

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