Blade deicing device

Abstract

According to one aspect, the invention relates to a device for de-icing a blade of a turbomachine (1) having an axis Y, comprising a blade (2) capable of rotational movement about a pivot shaft (20) having a radial axis X, and comprising a resistor (60), a power source (6) connected to the resistor (60), and a control rod (3) for the blade (2) connected to a control ring (11), the device being characterized in that the blade (2) is deiced by the power source (6). The control rod (3) comprises a pair of electrically conductive strips (32) connected to the rod for common rotation and located on the opposite side of the control ring (11) with respect to the radial axis X, and each of the pair of electrically conductive strips (32) comprises a first end in contact with a circular electrically conductive track (4) connected to a power source (6), and includes a second end connected to the resistor (60).

Description

Technical Field

[0001] The technical field of the invention is that of active blade systems requiring an electrical power source for electrical de-icing or anti-icing of the blades, in particular blades of turbomachines (e.g. turboprops or turbojets) for aviation. In the following, the term "de-icing" includes de-icing systems or anti-icing systems.

[0002] More particularly, the present invention relates to a system for supplying power to a de-icing device. Background Art

[0003] Under certain flight conditions, some blades or vanes of a turbine may become iced. This ice is usually removed by means of electric heaters mounted on the blades. This heating is done by resistors that must be powered in a limited space. This power supply is particularly complex for active blades.

[0004] Traditionally, a harness of two power cables is attached to the blade pivot lever by means of a clip to enter the pivot axis and connect to a connection node, which is connected to the heating element by wiring. As a result, the cables in the harness are mechanically stressed when the lever is rotated. A large number of cables and their supports and connectors are required to be able to connect multiple heating elements in parallel to the same power supply, which is unsatisfactory.

[0005] From US application 2009060720A1 a device is known in which each pivoting blade is provided with a pivot on which a bushing is mounted, on the outside of which two electrical collector contacts in the form of partly annular conductor tracks are arranged. The two contacts are connected to an electrical heating element mounted in the blade via conductors. The bushing is rotatably integrated with the blade and is mounted in a fixed cylindrical power supply box comprising two electrical distributor contacts supplied by two cables. The two electrical distributor contacts are in permanent contact with the two electrical collector contacts so as to be able to supply power to the electrical heating element in all possible rotational positions of the blade.

[0006] However, this solution is not satisfactory because it takes up some space around the blade pivot to mount the bushing and the box, and because a rod for controlling the rotation of the blades must be mounted on this pivot, the pivot must be lengthened, which reduces the overall size of the blade rotation device (i.e. all the blades) in the radial direction of the engine.

[0007] On the other hand, from an electrical point of view, in case it is desired to supply power to the heating elements of a plurality of consecutive blades from the same power source, this requires a large number of fixed cables and their connectors to electrically connect the power supply boxes in parallel. Summary of the invention

[0008] The present invention provides a solution to the above-mentioned problems, enabling reliable power supply to be achieved for heating elements of small overall size in moving blades.

[0009] One aspect of the invention relates to a device for deicing blades of a turbine having an axis Y, the device comprising a blade capable of pivoting movement about a pivot having a radial axis X, and comprising a resistor, an electric power source connected to the resistor, a lever for controlling the blade, the lever being connected to a control ring, the device being characterized in that the control lever is associated with a pair of conductive strips rotatably integrated with the lever and situated on the side opposite to the control ring with respect to the radial axis X, and in that each conductive strip of the pair comprises a first end in contact with a circular conductor track connected to the electric power source, and comprises a second end connected to the resistor.

[0010] In this way, there are no cables that are subject to mechanical stress when the blades rotate, which reduces the overall size and ensures contact regardless of the position of the blades. The conductor tracks are placed on the insulating material, forming a printed circuit.

[0011] Advantageously, the conductive strip is flexible and is supported on each circular conductor track by means of a spring action. The spring action of the strip ensures permanent contact with the conductor track.

[0012] Advantageously, each conductor track is covered by a protective cover. This cover not only protects the track but also keeps said track in contact with the conductive strip. This cover is made of non-conductive material and is placed on the track and integrated into the distribution ring; it can be made up of several parts if it is necessary to cover all tracks, regardless of their position. Another purpose of this cover is to protect the electric tracks, in particular during maintenance operations, in order to avoid accidents involving maintenance personnel.

[0013] According to a first embodiment, two conductor tracks are each provided on two opposite radial faces of a printed circuit of a distribution ring having axis Y. On each radial face of the printed circuit of the distribution ring is placed a conductive strip which "sandwiches" the printed circuit.

[0014] According to a second embodiment, the two conductor tracks are arranged in parallel on a common axial face of the printed circuit of the distribution ring having the axis Y. In this case, a plurality of conductive strips are arranged axially one above the other.

[0015] According to a third embodiment, the two conductor tracks are arranged in parallel on the same radial face of the printed circuit of the distribution ring having the axis Y. The two strips then have different lengths so that each strip is in contact with one of the two conductor tracks arranged at different distances from the blade pivot axis.

[0016] According to an alternative, the printed circuit of the distribution ring has planar portions. The printed circuit of the distribution ring, whose overall shape is annular, can have planar portions on which circular electrical tracks are arranged. In cross-section, the printed circuit can have a regular polygonal shape with at least the same number of faces as the number of blades, each face being perpendicular to the radial direction of the pivot axis of the corresponding blade.

[0017] Advantageously, the second end of each pair of conductive strips is connected to a resistor via a first conductive pad, which contacts a second conductive pad arranged on the pivot of the blade. The first pads may be arranged side by side along the circumference or axial direction, and the second pad is placed facing the first pad.

[0018] Another aspect of the invention relates to a turbomachine comprising a device for de-icing each blade having at least one of the above-mentioned characteristics.

[0019] Advantageously, the power supply is common to at least two blades. The turbine may comprise more than four blades, and the greater the number of blades, the more complex it becomes to connect each blade individually. Therefore, it is desirable to reduce the number of connections.

[0020] Advantageously, when the at least two de-icing devices are powered by a common power source, the conductor tracks are arranged in parallel.

[0021] The invention and its various applications will be better understood by reading the following description and reviewing the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] These drawings are presented for the purpose of illustrating and not limiting the invention in any way.

[0023] [ Figure 1 ] is a partial view of the turbine.

[0024] [ Figure 2 ] are details of a de-icing device according to the present invention applied to a plurality of blades.

[0025] [ Figure 3 ] is an exploded cross-sectional view of the device according to the present invention at the blade.

[0026] [ Figure 4 ] is a stereoscopic diagram of the device according to the present invention.

[0027] [ Figure 5 ] is a radial view of the second embodiment.

[0028] [ Figure 6 ] is an axial view of the second embodiment.

[0029] [ Figure 7] is a radial view of an alternative embodiment of the present invention.

[0030] [ Figure 8 ] is a radial view of the third embodiment.

[0031] [ Fig. 9 ] is an axial view of the third embodiment.

[0032] [ Fig.10 ] is from Figure 4 A stereoscopic view of the dispensing ring viewed from the rear of the device. DETAILED DESCRIPTION

[0033] Unless stated otherwise, identical elements appearing in different drawings have unique reference numerals.

[0034] exist Figure 1 In it, a turbine 1 with an axis Y can be seen, which has rotatably movable blades 2 fixed to a housing 10 and driven by control rods 3 .

[0035] Each control rod 3 has a radial axis of rotation X identical to the axis of rotation of the blade 2 and an arm 30 connected to the control ring 11. The control ring 11 drives the arm 3 and causes the rotation of each blade 2 to be controlled.

[0036] Each blade 2 comprises a pivot 20 with axis X cooperating with the lever 3. In this example, the pivot 20 has a circular shape with two flat sides 201 nesting in corresponding grooves 31 of the lever 3, other shapes being possible, such as square, rectangular or triangular.

[0037] The control rod 3 is associated with two strips 32 arranged on the side opposite to the arm 30 with respect to the radial axis X.

[0038] The two strips 32 are respectively in contact with a circular conductor track 4 connected to the power supply 6 . The conductor track 4 is circular so as to follow the trajectory of the end of each strip 32 during the movement of the control rod 3 .

[0039] The two strips 32 are respectively connected to a first conductive pad 33 which opens into the groove 31 of the control rod 3 .

[0040] The pivot 20 comprises two second conductive pads 200 placed facing the first conductive pads 33 and enabling the power source 6 to be connected to the resistor 60 for heating the blade 2 .

[0041] In such Figure 2 and Figure 3In the first embodiment shown, the two strips 32 are placed facing respectively the two radial surfaces 50 and 51 of the printed circuit 55 of the distribution ring 5. The first conductive pad 33 and the second conductive pad 200 are superposed along the axis X.

[0042] In this example, the conductor tracks 4 are arranged on the insulating material of the printed circuit 55 and form separate segments inserted radially into the distribution ring 5 from the outside of the ring. The ring has the structural function of supporting one or more printed circuits 55 and is not necessarily made of insulating material, since the ring does not come into contact with the conductor tracks of the one or more printed circuits 55.

[0043] According to another embodiment, the printed circuit 55 can be made into a single annular printed circuit, compared to individual segments, comprising conductor tracks 4 for deicing a plurality of blades, to which the conductive strips 32 are also intended to be connected. This annular printed circuit can be intended to be inserted axially into the distribution ring 5 (for example from the rear) when the control rod 3 and the associated pairs of conductive strips 32 have been installed. The conductor tracks 4 are in contact with the flexible strips 32 by inserting the printed circuit into an adapter support constituted by the distribution ring 5. In the case of a common power supply for all blades, the connection between the different conductor tracks 4 is electrically parallel. If only some of the blades are connected, the connection can be made by specific conductor tracks arranged on the annular track.

[0044] Alternatively, the annular printed circuit board can have a structural function, thereby forming a distribution ring without requiring a specific structural ring.

[0045] In this example of the first embodiment, as in Figure 4 As can be seen in FIG. 5 , two protective covers 52 cover the conductor tracks 4 and the strips 32 on both sides of the printed circuit 55 of the distribution ring 5 .

[0046] for Figure 5 and Figure 6 In the second embodiment shown in , the two tracks 40 and 41 and the two strips 320 and 321 are placed on the same radial surface 50 or 51 of the printed circuit 55 of the distribution ring 5. In this embodiment, the two tracks 40 and 41 are parallel and arranged in a circular arc, and the two strips 320 and 321 have different lengths and are offset relative to each other. Here, the first strip 320 is shorter to follow the first track 40, while the second strip 321 is longer to follow the second track 41. Figure 6 It can be seen in FIG. 3 that the second strip 321 passes over the first track 40 without contacting the first track 40. The connections 44 between the different conductor tracks 4 can be electrically connected in parallel to a power supply common to several blades.

[0047] exist Figure 7In the alternative shown in , the printed circuits of the distribution ring 5 do not form a perfectly circular shape, but rather have collectively a regular polygonal shape having as many straight portions as blades 2 .

[0048] In all examples, the strip 32 has an elastic function in order to maintain contact with the electric track. On one side, the end of the strip 32 clamps the electric track 4 via the third conductive pads 324 by its elastic function. These pads follow the circular movement of the control rod 3 and maintain contact with the track 4 by the elastic function of the strip 32.

[0049] exist Figure 8 and Fig. 9 In the third embodiment shown, the two tracks 42 and 43 are placed in parallel on the axial surface 53 of the distribution ring 5, which at this point has a surface 530 in the form of an arc of a circle. The strips 322 and 323 are superimposed along the axis X and are each in contact with one of the two tracks 42, 43. The two strips 322 and 323 are S-shaped and have an elastic action in the radial direction relative to the axis X of the blade 2 (i.e. the axis of the rod 3 associated with the two strips), so that the two strips always remain in contact with their respective tracks.

[0050] With regard to the first embodiment and possible solutions for supplying power to the conductor rail 4, Fig.10 5 , the printed circuits 55 are inserted radially into openings 56 in the distribution ring 5, these openings 56 being complementary in shape to said printed circuits 55. The supply of electricity to each printed circuit is carried out by connecting the openings 56 of the distribution ring 5 and the ports 57 of the rear axial face 58. Contacts 550 in the form of solder pads are provided on the printed circuits 55 facing each port 27 and enable the electrical tracks 4 to be connected to the power source 6.

[0051] The power delivered to the blades may be between 0.2 kilowatts (kW) and 500 kW.

[0052] The number of blades per stage of the turbine may be between 4 and 160. The total rotation angle of the moving blades is between 10° and 90°.

[0053] By removing the first connection pad 33 and the second connection pad 200, the conductive strip 32 can be directly connected to the pivot 20 of the blade 2. This alternative requires placing the conductive element on the pivot. Any other electrical connection solution known to those skilled in the art can be used without departing from the scope of the present invention.

Claims

1. A device for deicing a blade of a turbine (1) having an axis Y, the device comprising a blade (2) capable of rotating about a pivot (20) having a radial axis X, and comprising a resistor (60), a power source (6) connected to the resistor (60), and a control rod (3) for controlling the blade (2), the control rod (3) being connected to a control ring (11), the device being characterized in that the control rod (3) is connected to a pair of conductive strips (32, 320, 321, 322, 323), the pair of conductive strips (32, 320, 321, 322, 323) being rotatably integrated with the rod and being located on the opposite side of the control ring (11) relative to the radial axis X, and each conductive strip (32, 320, 321, 322, 323) of the pair of conductive strips comprising a first end in contact with a circular conductor track (4, 40, 41, 42, 43) connected to the power source (6), and comprising a second end connected to the resistor (60).

2. The deicing device according to claim 1, characterized in that: The conductive strips (32, 320, 321, 322, 323) are flexible and supported on each circular conductor track (4, 40, 41, 42, 43) by elastic action.

3. A de-icing device according to any one of the preceding claims, characterised in that Each conductor track (4, 40, 41, 42, 43) is covered by a protective cover (52).

4. A de-icing device according to any one of the preceding claims, characterised in that The two conductor tracks (4) are arranged on two opposite radial faces (50, 51) of a printed circuit (55) of a distribution ring (5) having an axis Y, respectively.

5. The deicing device according to any one of claims 1 to 3, characterized in that: The two conductor tracks (4, 42, 43) are arranged in parallel in the form of circular arcs on a common axial plane (53) of a printed circuit (55) of a distribution ring (5) having an axis Y.

6. The deicing device according to any one of claims 1 to 3, characterized in that: The two conductor tracks (4, 40, 41) are arranged in parallel on the same radial plane (51, 52) of a printed circuit (55) of a distribution ring (5) having an axis Y.

7. The deicing device according to any one of claims 4 to 6, characterized in that: The printed circuit (55) of the distribution ring (5) has a planar portion.

8. A de-icing device according to any one of the preceding claims, characterised in that The second end of each pair of conductive strips (32, 320, 321, 322, 323) is connected to the resistor (60) via a first conductive pad (33), which is in contact with a second conductive pad (200) disposed on the pivot (20) of the blade (2).

9. A turbomachine (1) comprising a device for de-icing each blade (2) according to any one of the preceding claims.

10. Turbine (1) according to the preceding claim, characterized in that The power source (6) is shared by at least two blades (2).

11. The turbine (1) according to claim 9, characterized in that The conductor tracks (40, 41; 42, 43) are arranged in parallel.

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