Apparatus for measuring pitch angle and associated method for measuring pitch angle

Abstract

One aspect of the invention relates to a device for measuring the blade pitch angle of a turbine engine having a first axis X, comprising:-a running wheel centered on the first axis X and provided with a plurality of blades arranged radially about the first axis X, each blade having a root, the blades are mounted at the root so as to pivot around a radial pivot second axis Y; -a fixed frame having an axis X, comprising at least one set of fixed magnetic sensors perpendicular to the first axis X; -a running wheel comprising a first magnetic target attached to the running wheel, each blade having a profile oriented along a third axis Z; -a first magnetic needle attached to the first blade and forming a first angle alpha with a third axis of the first blade, the first magnetic target serving as a marker for the first blade, the measuring device comprising a second magnetic needle attached to the second blade and forming a second angle beta with a third axis of the second blade, the first magnetic target serving as a marker for the first blade, the second angle beta is different from the first angle alpha.

Description

Technical Field

[0001] The technical field of the invention is variable pitch blades in turbomachines. The invention is particularly applicable to the aviation field, in particular to blades of turbojets or turboprops of aircraft.

[0002] The present invention relates to measuring the pitch angle of a blade, and in particular to a pitch angle measuring device and a pitch angle measuring method using the device. Background Art

[0003] Figure 1 A turbine 1 with a first axis X is shown, which has, from upstream to downstream, a fan module 2 and a twin spool gas generator formed by a first compressor 3, a second compressor 4, a combustion chamber 5 and two turbines 6 and 7 in series. The fan module 2 is mounted to a fixed frame 80 with a first axis X and comprises a movable wheel 21 centered on the first axis X. During operation of the turbine 1, the movable wheel rotates around the first axis X. The movable wheel is provided with a plurality of blades 22 arranged radially around the first axis X. As shown in FIG. Figure 2 As shown, each blade 22 comprises a root 22a at which the blade 22 is pivotally mounted about a radial pivot second axis Y. Therefore, each blade 22, in addition to rotating integrally with the mobile wheel 21 about the axis X, also pivots about the radial pivot second axis Y. This pivoting movement corresponds to a variation of the pitch angle of each blade 22. The pivoting is controlled according to flight requirements.

[0004] The pitch angle of the blade 22 corresponds to the orientation of the blade 22 relative to the axis X of the turbine 1. Figure 3 As shown, the first axis X of the turbine 1 corresponds to the flow direction of the gas circulating in the turbine, indicated by the arrow F. When the blade 22 is in the "mark" position indicated by the line Pd, it allows the gas to flow and its pitch angle relative to the tangential straight line Δ is 90°. When the blade 22 is in the "reverse" position indicated by the line Pr, its pitch is reversed and the flow direction of the gas around the blade 22 is reversed. The pitch angle is then in an angular range of negative angles of approximately 0 degrees to -20 degrees. Between these two positions, the blade is in the so-called flight pitch position Pv. In a system with a variable blade angle, measuring the blade angle makes it possible to control and adjust the blade angle accordingly according to flight requirements.

[0005] There are devices that use a needle made of ferromagnetic material coupled to a magnetic sensor to measure the pitch angle. An example of this type of solution is Figure 4 and Figure 5As shown. A magnetic needle 110 attached to the root 22a of the blade 22 whose pitch angle is to be measured passes in front of a fixed sensor 120, which then detects a change in the magnetic field. By analyzing the signal detected by the fixed sensor 120, the blade pitch angle can be determined by using a reference signal corresponding to the detection of the absolute reference target 13 and the relative reference target 14.

[0006] However, the angular measurement range of this type of device is usually limited by the turbine structure. Figure 6 As shown, due to the physical limitations of the detection field of the fixed sensor 120 and the limitations on the length of the magnetic needle 110 imposed by the positioning of other components of the turbine, there is a measurement blind angle θ M For example, in Figure 6 For the blade 22 and the magnetic needle position 110 d and 110 V0 The corresponding position P d With P V0 At positions between 1 and 2, the magnetic needle 110 no longer enters the detection field of the fixed sensor 120. Typically, the pitch angle range between 60 and 90 degrees is not measurable.

[0007] Generally speaking, for some turbojet engine structures, it is not possible to measure the entire angular range of the pitch angle covering the "mark" position and the "reverse" position. However, it is advantageous to measure all blade pitch positions. For example, when the turbojet engine is started, the blades are usually in the "mark" position. However, this position may not be measurable when the position of the corresponding magnetic needle 110 is in the dead angle of the fixed sensor 120. Summary of the invention

[0008] The present invention provides a solution to the problems discussed above, by enabling the measurement range of the pitch angle to be widened in order to improve the control of this parameter.

[0009] A first aspect of the invention relates to a device for measuring the pitch angle of a blade of a turbine having a first axis X, the device comprising:

[0010] a mobile wheel centered on a first axis X, provided with a plurality of blades arranged radially about the first axis X, each blade having a root at which the blade is pivotally mounted about a radially pivoting second axis Y;

[0011] a fixed frame having an axis X, comprising at least one set of fixed magnetic sensors perpendicular to the first axis X,

[0012] - the movable wheel comprises a first magnetic target, the first magnetic target being fixed on the movable wheel,

[0013] Each blade has a profile oriented along a third axis Z;

[0014] - a first magnetic needle, which is attached to the first blade and forms a first angle α with the third axis of the first blade, the first magnetic target is used as a marker for the first blade, the measuring device includes a second magnetic needle, which is attached to the second blade and forms a second angle β with the third axis of the second blade, the second angle β is different from the first angle α.

[0015] By means of the invention, the angular range of pitch angle measurement is widened.Due to the offset between the first magnetic needle and the second magnetic needle, pitch angles corresponding to extreme blade pitch positions such as the "mark" position and the "reverse" position can be measured.

[0016] Advantageously, the second angle β is between α+20 degrees and α+50 degrees. Thus, a pitch angle measurement range of up to 110 degrees can be achieved.

[0017] Advantageously, the first angle α is between 70 and 130 degrees. The value of the first angle α depends on the angular range of the pitch angle measurement. d , the pitch angle can be equal to 85 degrees or 90 degrees relative to the tangent line Δ. r , the pitch angle may be -5 degrees or -15 degrees. This value range enables the first magnetic needle and the second magnetic needle to be arranged so that they can enter the detection field of the magnetic sensor.

[0018] In a first embodiment, the movable wheel includes a second magnetic target that serves as a marker for the second blade, the first blade and the second blade are continuous, and the at least one set of fixed magnetic sensors includes a single set of magnetic sensors. This configuration reduces the number of needles mounted on at least some of the plurality of turbine blades.

[0019] In a second embodiment, the first blade and the second blade are the same blade, and the fixed frame comprises a first set of fixed magnetic sensors and a second set of fixed magnetic sensors perpendicular to the first axis X. This configuration enables the pitch angle of each turbine blade to be measured regardless of whether the value of the pitch angle is within the angle measurement range.

[0020] In the second embodiment, the first magnetic needle and the second magnetic needle have the same length. This configuration makes it possible to enhance the redundancy of the measurement system and improve the accuracy of the pitch angle measurement.

[0021] In an alternative to the second embodiment, the first magnetic needle and the second magnetic needle have different lengths. This configuration enables balancing the redundancy of the measurement system while maintaining an extended angular range of pitch angle measurement.

[0022] Advantageously, the first magnetic needle and the second magnetic needle have different shapes. This configuration facilitates signal processing by the processing unit.

[0023] A second aspect of the present invention relates to a method for measuring a blade pitch angle of a turbine, the method using the measuring device according to the first embodiment, the measuring device further comprising a processing unit, the method comprising:

[0024] - Single detection step (E1a): a single magnetic field change is detected by a single set of magnetic sensors, or

[0025] - Multiple detection steps (E1b): detecting the first magnetic field change and the second magnetic field change by a single set of magnetic sensors, wherein:

[0026] if the method comprises a single detection step (E1a), a single magnetic field variation corresponds to the passage of a first magnetic needle or a second magnetic needle in the vicinity of a single row of sensors,

[0027] - If the method comprises a plurality of detection steps (E1b), the first magnetic field variation corresponds to the passage of the first magnetic needle near a single set of sensors and the second magnetic field variation corresponds to the passage of the second magnetic needle near a single set of sensors; and wherein, after a single detection step (E1a) or a plurality of detection steps (E1b), the method comprises a step (E4) of calculating, by a processing unit, the pitch angle based on the electrical signal representing the magnetic field variation.

[0028] A third aspect of the present invention relates to a method for measuring a blade pitch angle of a turbine, the method being performed by a measuring device according to the second embodiment or an alternative thereof, the measuring device further comprising a processing unit, the method comprising:

[0029] - a single detection step (E2a): detecting a single magnetic field change by the first set of magnetic sensors or by the second set of magnetic sensors, or

[0030] - Multiple detection steps (E2b): a first group of magnetic sensors detects a first magnetic field change, and a second group of magnetic sensors detects a second magnetic field change.

[0031] 2. Magnetic field changes,

[0032] in:

[0033] if the method comprises a single detection step (E2a), a single magnetic field variation corresponds to the passage of a first magnetic needle in the vicinity of the first set of magnetic sensors or the passage of a second magnetic needle in the vicinity of the second set of sensors,

[0034] -If the method comprises a plurality of detection steps (E2b), the first magnetic field variation corresponds to the passage of a first magnetic needle near a first set of sensors, and the second magnetic field variation corresponds to the passage of a second magnetic needle near a second set of sensors; and wherein, after a single detection step (E2a) or a plurality of detection steps (E2b), the method comprises a step (E5) of calculating, by a processing unit, the pitch angle based on an electrical signal representing the magnetic field variation.

[0035] The present invention and its various applications will be better understood by reading the following description and examining the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] These drawings are set forth by way of illustration of the invention and are not intended to limit the invention in any way.

[0037] - Figure 1 A schematic representation of a turbine according to the prior art is shown.

[0038] - Figure 2 A blade root of a variable pitch turbine according to the prior art is shown.

[0039] - Figure 3 Represents different pitch positions of the turbine blades.

[0040] - Figure 4 A three-dimensional view showing a turbine blade angle measuring device according to the prior art.

[0041] - Figure 5 yes Figure 4 Cross section of a turbine blade angle measurement device.

[0042] - Figure 6 2 is a diagram showing a measurement blind spot of a turbine blade angle measurement device according to the prior art.

[0043] - Figure 7 Denotes the direction of a third axis along which each turbine blade of the plurality of turbine blades according to the present invention is oriented.

[0044] - Figure 8a and Figure 8b The positioning of the first magnetic needle and the second magnetic needle according to the present invention is schematically shown.

[0045] - Figure 9a and Figure 9b FIG. 4 shows a device for measuring a pitch angle according to an embodiment of the present invention.

[0046] - Fig.10a , Fig.10b , Fig.10c and Fig.10dA pitch angle measuring device according to a second embodiment of the present invention is shown for different blade pitch angles.

[0047] - Fig.11a , Fig.11b , Fig.11c and Fig.11d A pitch angle measuring device according to an alternative of the second embodiment of the present invention is shown for different blade pitch angles.

[0048] - Fig.12 Examples of signals received by the processing unit of the pitch angle measurement device according to the first embodiment of the invention are schematically represented for different blade pitch angles.

[0049] - Fig.13 Examples of signals received by a processing unit of a pitch angle measurement device according to a second embodiment of the invention are schematically represented for different blade pitch angles.

[0050] - Fig.14 Examples of signals received by a processing unit of a pitch angle measuring device according to an alternative to the second embodiment of the invention are schematically represented for different blade pitch angles. DETAILED DESCRIPTION

[0051] These drawings are set forth by way of illustration of the invention and are not intended to limit the invention in any way.

[0052] Unless otherwise stated, identical elements appearing in different drawings have a single reference number.

[0053] The present invention proposes to use a combination of magnetic needles attached to the blades to widen the measurement range of the pitch angle of variable pitch blades of a turbine. As described below, this widening will be performed by an angular offset of the magnetic needles.

[0054] Considered herein is a turbojet-type turbine 1 comprising Figure 1 Components in the turbine, in particular the fan module 2, which includes a movable wheel 21 and blades 22. The first compressor 3 is connected to the turbine 7 via a turbine shaft 71 with an axis X to form a low-pressure spool. The second compressor 4 is connected to the turbine 6 via a shaft 61 with an axis X to form a high-pressure spool. The fixed structural components of the turbine include an intake casing 8 between the fan module 2 and the compressor 3 upstream of the gas generator, and a compressor inter-casing 9 between the compressor 3 and the compressor 4. Downstream, the force transmission from the engine to the suspension is ensured by the exhaust casing 10. The movable wheel 21 is integrated with the rotor of the compressor 3 rotatably mounted in the intake casing 8.

[0055] like Figure 7 As shown, each blade 22 defines a direction of a third axis Z.

[0056] The magnetic needle 11 is attached to the root of at least a part of the blades 22 of the movable wheel 21. In other words, the blade 22 of the movable wheel 21 includes one magnetic needle 11 or two magnetic needles 11, or no magnetic needle at all. There are at least two magnetic needles 11, which are carried by the same blade 22 of the movable wheel 21 or by two different blades of the movable wheel 21. The magnetic needles 11 may be present on some blades 22 of the movable wheel 21 or even on all blades 22 of the movable wheel 21. The magnetic needles 11 are divided into a first subset including at least one magnetic needle 11A (hereinafter referred to as an A-type needle) and a second subset including at least one magnetic needle 11B (hereinafter referred to as a B-type needle).

[0057] A processing unit is provided to receive and process the electrical signal from the magnetic sensor, as will be described below.

[0058] like Figure 8a As shown, each A-type needle 11A forms a first angle α with the third axis Z of the blade to which it is attached at the root. Figure 8b As shown, each B-type needle 11B forms a second angle β with the third axis Z of the blade to which it is attached. The second angle β is different from the first angle α. For example, the value of the first angle α is between 70 degrees and 130 degrees. For example, the second angle β is between α+20 degrees and α+50 degrees.

[0059] The mobile wheel 21 comprises a magnetic reference target 13 which is attached to the mobile wheel 21 and serves as an absolute orientation reference. The magnetic reference target has a typical shape (comprising, for example, three claws) so that, when the mobile wheel 21 rotates about the axis X, a recognizable magnetic field change is generated when the magnetic reference target passes in front of the magnetic sensor mentioned above and described below. The magnetic reference target is particularly useful for counting the number of revolutions.

[0060] In addition, the movable wheel 21 includes a relative magnetic target 14, which is fixed to the movable wheel 21 and serves as a relative orientation mark, so that some blades 22 of the movable wheel 21 can be identified on the electrical signal received by the processing unit (as will be seen later). The relative magnetic target 14 also has a typical shape (for example, it includes two claws), so that when the movable wheel 21 rotates around the first axis X, when the relative magnetic target passes in front of the aforementioned magnetic sensor, an identifiable magnetic field change is generated.

[0061] like Figure 9a and Figure 9bAs shown, in the first embodiment of the blade angle measuring device according to the present invention, the fixed frame 80 includes a single row of magnetic sensors 12. For example, the row of magnetic sensors includes 4 magnetic sensors. The row of magnetic sensors 12 is perpendicular to the first axis X.

[0062] When the magnetic needles 11A, 11B enter the detection field of the row of magnetic sensors 12, each magnetic sensor in the row of magnetic sensors 12 detects the same signal. This same signal represents the change in the magnetic field induced by the magnetic needles 11A, 11B entering the detection field of the row of magnetic sensors 12. Therefore, these multiple magnetic sensors ensure the redundancy of the received signal and ensure the reception of the signal in the event that, for example, one of the sensors in the row of magnetic sensors 12 is defective. The signal received by the row of magnetic sensors 12 is transmitted to the processing unit. Typically, the signal is a voltage peak. Preferably, the needles 11A, 11B are identical. This configuration avoids the need for different needles.

[0063] In this embodiment, the A-type needle 11A is attached to the root of at least one blade 22 of the movable wheel 21, and the B-type needle 11B is attached to the root 22a of a blade continuous with the at least one blade on the movable wheel 21. In this embodiment, the blade carrying the A-type needle is called the A-type blade, and the blade carrying the B-type needle is called the B-type blade.

[0064] exist Figure 9a and Figure 9b In FIG. 1 , it is observed that the blades of type A and type B enter the detection field of a row of magnetic sensors 12. The pitch angle of the blades of type A is the same as the pitch angle of the blades of type B. For example, in Figure 9a In FIG. 1 , it can be observed that the needle 11A attached to the first blade passes at the boundary of the detection field of a row of magnetic sensors 12. In addition, as Figure 9b As can be seen in FIG. 1 , due to the offset between the first angle α and the second angle β, the needle 11B attached to the continuous blade enters the detection field of the row of magnetic sensors 12, but Figure 9a The comparison is no longer in the center of the detection field.

[0065] In the blade angle measuring device according to the present invention, Fig.10a , Fig.10b , Fig.10c and Fig.10d In the second embodiment shown, the fixed frame 21 includes a first row of magnetic sensors 12A and a second row of magnetic sensors 12B different from the first row of magnetic sensors 12A. For example, each of the first row of magnetic sensors 12A and the second row of magnetic sensors 12B includes four magnetic sensors.

[0066] The first row 12A and the second row 12B of magnetic sensors are perpendicular to the first axis X. The first row 12A and the second row 12B of magnetic sensors are axially offset along the first axis X. Fig.10a , Fig.10b , Fig.10c and Fig.10d Different blade 22 pitch positions are shown.

[0067] Furthermore, the processing unit includes a first module and a second module.

[0068] When the magnetic needles 11A and 11B enter Fig.10a , Fig.10b , Fig.10c and Fig.10d When the detection field of the first row of magnetic sensors 12A in the first row of magnetic sensors 12A is entered, the magnetic sensors of the first row of magnetic sensors 12A detect a first signal, which is the same for each sensor. Therefore, these multiple magnetic sensors ensure the redundancy of the received signal and ensure the reception of the signal in the case where, for example, one of the sensors in the first row of magnetic sensors 12A is defective or the magnetic needles 11A, 11B are not in the detection field of a sensor. The first signal represents the change in the magnetic field caused by the magnetic needles 11A, 11B entering the detection field of the first row of magnetic sensors 12A. The first signal is sent and received by the first module of the processing unit. Usually, the first signal is a voltage peak.

[0069] When the magnetic needles 11A and 11B enter Fig.10a , Fig.10b , Fig.10c and Fig.10d When the magnetic sensors of the second row of magnetic sensors 12B enter the detection field of the second row of magnetic sensors 12B, the magnetic sensors of the second row of magnetic sensors 12B detect a second signal, which is the same for each sensor. Therefore, these multiple magnetic sensors ensure the redundancy of the received signal and ensure the reception of the signal in the case where, for example, one of the sensors in the second row of magnetic sensors 12B is defective or the magnetic needles 11A, 11B are not in the detection field of a sensor. The second signal represents the change in the magnetic field caused by the magnetic needles 11A, 11B entering the detection field. The second signal is sent and received by the second module of the processing unit. Usually, the second signal is a voltage peak.

[0070] In this embodiment, at least one blade 22 of the movable wheel 21 includes an A-type needle 11A and a B-type needle 11B. The lengths of the A-type needle 11A and the B-type needle 11B are the same.

[0071] exist Fig.10a In the embodiment, only the needle 11B enters the field of the first row of magnetic sensors 12A and the field of the second row of magnetic sensors 12B.

[0072] exist Fig.10b In the embodiment, both the needle 11A and the needle 11B enter the field of the first row of magnetic sensors 12A and the field of the second row of magnetic sensors 12B.

[0073] exist Fig.10c In the embodiment, only the needle 11A enters the field of the first row of magnetic sensors 12A and the second row of magnetic sensors 12B.

[0074] exist Fig.10d In the embodiment, only the needle 11A enters the field of the first row of magnetic sensors 12A.

[0075] In the blade angle measuring device according to the present invention, Fig.11a , Fig.11b , Fig.11c and Fig.11d In an alternative to the second embodiment shown, the A-type needle 11A has a first length l1, and the B-type needle 11B has a second length l2 greater than the first length l1. Therefore, the A-type needle 11A only enters the detection field of the first row of sensors 12A. In addition, the B-type needle 11B enters the detection field of both the first row of sensors 12A and the second row of magnetic sensors 12B. Fig.10a , Fig.10b , Fig.10c and Fig.10d Different blade 22 pitch positions are shown.

[0076] exist Fig.11a In the embodiment, only the needle 11B enters the field of the second row of magnetic sensors 12B.

[0077] exist Fig.11b In the above example, the needle 11A is not detected. The needle 11B enters both the detection field of the first row of magnetic sensors 12A and the detection field of the second row of magnetic sensors 12B.

[0078] exist Fig.11c In FIG. 1 , the needle 11A does not enter the field of the second row of magnetic sensors 12B, but enters the field of the first row of magnetic sensors 12A.

[0079] exist Fig.11d In the embodiment, only the needle 11A enters the field of the first row of magnetic sensors 12A.

[0080] Therefore, due to the offset between the first angle α and the second angle β, the pitch angle measuring device according to the present invention is able to measure the pitch angle in a wider angle range than the prior art (usually in an angle range between 100 degrees and 110 degrees). In fact, this offset makes it possible to define three angle measurement sub-ranges, the limits of which can reach values ​​corresponding to the extreme pitch positions of the blade 22 (i.e. the "mark" position and the "reverse" position).

[0081] In the following, a method for measuring the pitch angle of blades with variable pitch angle according to the invention will be described.In flight, when a change in the pitch angle of a blade 22 is actuated, all blades 22 pivot about their radial second axis Y by the same angle.

[0082] In operation, the pitch angle of the blades 22 of the fan module 2 is in the "reverse" position (corresponding to the blade angle θ 1 ) and the "mark" position (corresponding to the pitch angle θ 2 ) in the angle range [θ 1 θ 2 ] within the changes.

[0083] Angle range [θ 1 θ 2 ] is divided into three sub-ranges: the first angle range [θ 1 ; δ]; the so-called "multi-range" [δ; γ] in which the A-type needle 11A and the B-type needle 11B are detected; and the second angular range [γ; θ in which only the B-type needle 11B is detected 2 ].

[0084] For example, the range [θ1; θ2] is [-20 degrees; 90 degrees]. For example, if the first angle range [θ1; δ] is [-20 degrees; 30 degrees], the offset between the first angle α and the second angle β can be selected to be equal to 50 degrees. Therefore, the second angle range [δ; θ2] is [40 degrees; 90 degrees].

[0085] The common blade pitch angle is recorded as

[0086] Furthermore, assuming that the reference magnetic target 13 has a shape with three claws, the opposing magnetic target 14 has a shape with two claws.

[0087] The following describes a first embodiment of the method performed by the first embodiment of the blade angle measuring device according to the present invention. Two consecutive blades of the movable wheel 21 are respectively an A-type blade and a B-type blade.

[0088] If the common pitch angle to be measured is Included in the first angle range [θ 1 ; δ], when the corresponding blade passes in front of the row of magnetic sensors 12, the A-type needle 11A is detected by the row of magnetic sensors 12.

[0089] If the common pitch angle to be measured is Included in the multi-range [δ; γ], when the corresponding blade passes in front of the row of magnetic sensors 12, the A-type needle 11A and the B-type needle are detected by the row of magnetic sensors 12.

[0090] If the common pitch angle to be measured is Included in the second angle range [γ; θ2], when the corresponding blade passes in front of the row of magnetic sensors 12, the B-type needle 11B is detected by the row of magnetic sensors 12.

[0091] In operation, the mobile wheel 21 rotates about the axis X. The row of magnetic sensors 12 detects in real time the reference magnetic target 13 , the relative magnetic target 14 and at least one type A needle 11A or type B needle 11B entering its detection field.

[0092] When the magnetic reference target enters the detection field of the row of magnetic sensors 12, the three claws of the magnetic reference target continuously generate three magnetic field changes, so the processing unit receives three consecutive peak values ​​P ABS1 , P ABS2 and P ABS3 The absolute reference signal is formed.

[0093] When the relative magnetic target 14 enters the detection field of the row of magnetic sensors 12, the two claws of the secondary target continuously generate two magnetic field changes, so the processing unit receives two consecutive peak values ​​P REL1 and P REL2 The relative reference signal is formed.

[0094] When the current blade 22 including the pins 11A, 11B and in particular the root 22a thereof passes in front of a row of sensors 12, according to the common pitch angle For values ​​of , both configurations are possible.

[0095] If the current blade 22 is an A-type blade, the processing unit will receive signals from the row of magnetic sensors 12 only if the A-type needle 11A attached to the root of the blade enters the detection field of the row of magnetic sensors 12. In other words, at a common pitch angle Included in the first angle range [θ 1 ; γ] or in the multi-range [δ; γ], the processing unit will receive the signal. Otherwise, that is, if the common pitch angle Included in the angle range [γ; θ 2 ], the processing unit will not receive any signal.

[0096] However, as the active wheel 21 continues to rotate about the axis X, the successive blades (i.e. the blades following the current blade 22 on the active wheel 21) are type B blades. Therefore, as the successive blades pass, if the common pitch angle Included in the angle range [γ; θ 2 ], since the B-type needle 11B is detected in the detection field of the row of magnetic sensors, the processing unit will receive the signal from the row of magnetic sensors 12.

[0097] Fig.12 For the common pitch angle Schematic diagram of different types of signals received by the processing unit for different values ​​of .

[0098] When the common pitch angle to be measured Included in the range [γ; θ 2 ] (indicated by a value equal to 90 degrees), that is, when the blade 22 of the movable wheel 21 is in the "mark" position, the processing unit receives between the two relative reference signals a peak value P corresponding to the passage of the B-type needle 11B B . By the peak value P REL1 and P REL2 The relative reference signal formed is compared with the peak value P B The time offset between the two enables the calculation of the common pitch angle from the geometric and kinematic parameters of the turbine

[0099] The geometrical and kinematic parameters of the turbine are, for example, the distance from the axis X to the outer diameter of the active wheel 21 (this distance corresponds to the support area of ​​the blade root 22a), the angle between the reference magnetic target and the secondary target (this angle corresponds to the angle between the peak P REL1 and P REL2 The relative reference signal formed), the position of the row of magnetic sensors 12 relative to the blade root 22a entering its magnetic field, and the rotation speed of the active wheel 21.

[0100] When the common pitch angle to be measured Included in multiple ranges [δ; γ] (in Fig.12 When the processing unit receives a first peak value P between the two secondary reference signals, A , then receive the second peak value P B The first peak value P A Corresponding to the A-type blade entering the detection area of ​​a row of sensors 12, the second peak value P B This corresponds to the B-type blade following the A-type blade on the movable wheel 21 entering the detection area of ​​a row of sensors 12. The time offset between the first peak and the second peak corresponds to the angular offset between the A-type blade and the subsequent B-type blade.

[0101] When the common pitch angle to be measured Included in the range [θ 1 ;γ] in (in Fig.12 =0 degrees), i.e. when the blade 22 of the movable wheel 21 approaches the "reverse" position, the processing unit receives between the two relative reference signals a peak value P corresponding to the passage of the A-type needle 11A. A . By the peak value P REL1 and PREL2 The relative reference signal formed is compared with the peak value P B The time offset between makes it possible to calculate the common pitch angle from the geometric and kinematic parameters of the turbine 1

[0102] By the peak value P REL1 and P REL2 The position of the relative reference signal is formed by the peak value P received previously by the processing unit. ABS1 , P ABS2 and P ABS3 The same absolute reference signal counts are formed to identify the peak value P A and P B The blades 22 of the movable wheel 21 are provided.

[0103] A second embodiment of the method performed by the second embodiment of the blade angle measuring device according to the present invention is described below.

[0104] At least one blade 22 of the movable wheel 21 includes an A-type needle 11A and a B-type needle 11B. The lengths of the A-type needle 11A and the B-type needle 11B are the same.

[0105] If the common pitch angle Included in the first angle range [θ 1 δ], when the corresponding blade 22 enters the detection field of the first row of magnetic sensors 12A and the second row of magnetic sensors 12B, the first row of magnetic sensors 12A and the second row of magnetic sensors 12B only detect the A-type needle 11A.

[0106] If the common pitch angle Included in the multi-range [δ; γ], when the corresponding blade 22 enters the detection field of the first row of magnetic sensors 12A and the second row of magnetic sensors 12B, the first row of magnetic sensors 12A and the second row of magnetic sensors 12B detect the A-type needles 11A and the B-type needles 11B.

[0107] If the common pitch angle Included in the second angle range [γ; θ 2 ], when the corresponding blade 22 enters the detection field of the first row of magnetic sensors and the second row of magnetic sensors 12B, the first row of magnetic sensors and the second row of magnetic sensors 12B only detect the B-type needle 11B.

[0108] Fig.13 For common pitch angle Schematic diagram of different types of signals received by the processing unit for different values ​​of .

[0109] For the common pitch angles shown Each value of represents a first signal a and a second signal b. The first signal a corresponds to the signal received by the first row of magnetic sensors 12a. The second signal b corresponds to the signal received by the second row of magnetic sensors 12b.

[0110] When the common pitch angle to be measured Included in the second angle range [γ; θ2] (in Fig.13 ), that is, when the blades of the movable wheel 21 are in the "mark" position, the first module of the processing unit receives a first signal a which comprises, between the two relative reference signals, a primary peak P corresponding to the passage of the B-type needle 11B B1 The second module of the processing unit receives a second signal b which comprises, between the two relative reference signals, a secondary peak P corresponding to the passage of the needle 11B. B2 .

[0111] like Fig.13 As shown, the primary peak P B1 With the secondary peak P B2 There is a time offset Δt between the first row of magnetic sensors 12A and the second row of magnetic sensors 12B. This time offset Δt is due to the axial offset along the axis X between the first row of magnetic sensors 12A and the root 22a of the blade 22 entering its detection field. Therefore, the distance between the first row of magnetic sensors 12A and the root 22a of the blade 22 entering its detection field is different from the distance between the second row of magnetic sensors 12B and the root 22a of the blade 22. In other words, the first row of magnetic sensors 12A and the second row of magnetic sensors 12B do not simultaneously detect the change in the magnetic field caused by the needle 11B entering their respective detection fields.

[0112] As in the first embodiment, on the one hand, the peak value P REL1 and P REL2 The relative reference signal formed is compared with the primary peak value P in the first signal a B1 There is a time offset between them. On the other hand, the peak value P REL1 and P REL2 The relative reference signal formed is compared with the secondary peak value P in the second signal b B2 There is a time offset between them, which enables the calculation of two common pitch angles according to the geometric and kinematic parameters of the turbine 1 Therefore, the common pitch angle is increased The calculation accuracy.

[0113] When the common pitch angle to be measured Included in the multi-range [δ; γ] (in Fig.13 When the first module of the processing unit receives the first signal a, the first signal a includes a first primary peak value P between the two relative reference signals. A1, followed by the second primary peak P B1 The first primary peak value P A1 The A-type needle 11A corresponding to the blade 22 facing the first row of sensors 12A enters the detection field of the first row of sensors 12A. B1 The B-type needle 11B corresponding to the blade 22 enters the detection field of the first row of sensors 12A. A1 With the second peak P B1 The time offset between them corresponds to the angular offset between the A-type needle 11A and the B-type needle 11B of the blade 22 .

[0114] The second module of the processing unit receives the second signal b. The second signal b includes a first secondary peak value P between two relative reference signals. A2 , followed by the second secondary peak P B2 The first secondary peak value P A2 The A-type needle 11A corresponding to the blade 22 facing the second row of sensors 12B enters the detection field of the second row of sensors 12B. B2 The B-type needle 11B corresponding to the blade enters the detection field of the second row of sensors 12B. A2 With the second peak P B2 The time offset between them corresponds to the angular offset between the A-type needle 11A and the B-type needle 11B of the blade.

[0115] The common pitch angle is thus obtained The four measured values ​​are: the magnetic field changes caused by the A-type needle 11A of the current blade 22 detected by the first row of magnetic sensors 12A and the second row of magnetic sensors 12B, and the magnetic field changes caused by the B-type needle 11B of the current blade 22 detected by the first row of magnetic sensors 12A and the second row of magnetic sensors 12B. Therefore, the common pitch angle is improved The calculation accuracy.

[0116] When the common pitch angle to be measured Included in the first angle range [θ 1 ;γ] in (in Fig.13 , that is, when the blade 22 of the movable wheel 21 approaches the "reverse" position, the first module of the processing unit receives the first signal a. The first signal a comprises, between the two relative reference signals, a primary peak P corresponding to the passage of the A-type needle 11A A1 The second module of the processing unit receives a second signal b which comprises, between two relative reference signals, a secondary peak P corresponding to the passage of the needle 11A. A2 .

[0117] exist Fig.13The primary peak P observed in A1 With the secondary peak P A2 The time offset between 1 and 2 is due to the axial offset of the first row of magnetic sensors 12A and the second row of magnetic sensors 12B along the axis X. Therefore, the distance between the first row of magnetic sensors 12A and the root 22a of the blade 22 entering its detection field is different from the distance between the second row of magnetic sensors 12B and the root 22a of the blade 22. In other words, the first row of magnetic sensors 12A and the second row of magnetic sensors 12B do not simultaneously detect the change in the magnetic field caused by the needle 11A entering their respective detection fields.

[0118] On the one hand, the peak value P REL1 and P REL2 The relative reference signal formed is compared with the solid line primary peak value P in the first signal a A1 There is a time offset between them. On the other hand, the peak value P REL1 and P REL2 The relative reference signal formed is compared with the secondary peak value P in the second signal b A2 There is a time offset between the two, so that the two common pitch angles can be calculated based on the geometric and kinematic parameters of the turbine 1 Therefore, the common pitch angle is increased The calculation accuracy.

[0119] An alternative to the second embodiment of the method according to the invention will now be described, which alternative is formed by an alternative to the second embodiment of the device according to the invention for measuring the pitch angle.

[0120] At least one blade 22 of the movable wheel 21 includes an A-type needle 11A and a B-type needle 11B. In this alternative, the A-type needle 11A has a first length l1 and the B-type needle has a second length l2 greater than the first length l1, so that the A-type needle 11A is detected only by the first row of sensors 12A, while the B-type needle 11B is detected by the first row of magnetic sensors 12A and the second row of magnetic sensors 12B. An opposite configuration is also possible, in which the A-type needle 11A is detected only by the second row of sensors 12B, while the B-type needle 11B is detected by the first row of magnetic sensors 12A and the second row of magnetic sensors 12B. The following description will be converted to this reverse configuration by interchanging the first row of magnetic sensors and the second row of magnetic sensors.

[0121] If the common pitch angle to be measured is Included in the first angle range [θ 1 δ], when the corresponding blade 22 enters the detection field of the first row of magnetic sensors 12A, only one A-type needle 11A is detected and is only detected by the first row of magnetic sensors 12A.

[0122] If the common pitch angle to be measured is Included in the multi-range [δ; γ], the type A needle 11A is detected by the first row of magnetic sensors 12A; when the corresponding blade 22 enters the corresponding detection fields of the first row of magnetic sensors 12A and the second row of magnetic sensors 12B, the type B needle 11B is detected by the first row of magnetic sensors 12A and the second row of magnetic sensors 12B.

[0123] If the common pitch angle to be measured is Included in the second angle range [γ; θ 2 ], when the corresponding blade 22 enters the detection field of the first row of magnetic sensors 12A and the second row of magnetic sensors 12B, only the B-type needle 11B is detected.

[0124] Fig.14 For the common pitch angle Schematic diagram of different types of signals received by the processing unit for different values ​​of .

[0125] For the common pitch angles shown Each value of represents a first signal a and a second signal b. The first signal a corresponds to the signal received by the first row of magnetic sensors 12a. The second signal b corresponds to the signal received by the second row of magnetic sensors 12b.

[0126] When the common pitch angle to be measured Included in the second angle range [γ; θ 2 ] Fig.14 , that is, when the blade 22 of the movable wheel 21 is in the "mark" position, the A-type needle 11A of the blade 22, which includes the A-type needle 11A and the B-type needle 11B facing the first row of sensors 12A and the second row of sensors 12B, is not detected. However, the B-type needle 11B is detected by the first row of sensors 12A. Therefore, the first module of the processing unit receives the first signal a, which includes the primary peak value P between the two relative reference signals. B1 The second module of the processing unit receives a second signal b. The second signal b includes a second peak value P between two relative reference signals. B2 , the second peak corresponds to the B-type needle 11B of the blade 22 passing through the field of the second row of sensors 12B. In the first signal a, the peak P REL1 and P REL2 The relative reference signal formed is compared with the primary peak value P B1 There is a time offset between them, and in the second signal b, the peak P REL1 and P REL2 The relative reference signal formed is compared with the secondary peak value P B2There is a time offset between them, which enables the calculation of a common pitch angle from the geometric and kinematic parameters of the turbine 1

[0127] When the common pitch angle to be measured Included in the multi-range [δ; γ] (in Fig.14 When the first module of the processing unit receives the first peak value P between the two relative reference signals, A1 and the second peak P B1 , the first peak P A1 The A-type needle 11A corresponding to the blade 22 facing the first row of magnetic sensors 12A and the second row of magnetic sensors 12B enters the detection field of the first row of magnetic sensors 12A, and the second peak value P B1 The second module of the processing unit receives a single peak value P corresponding to the B-type needle 11B of the blade 22 entering the detection field of the second row of sensors 12B between the two relative reference signals. B2 .

[0128] When the common pitch angle to be measured Included in the range [θ1; γ] (in Fig.14 , that is, when the blade 22 of the movable wheel 21 approaches the "reverse" position, the B-type needle 11B of the blade 22 facing the first row of sensors 12A and the second row of sensors 12B is not detected. Therefore, the second module of the processing unit receives the second signal b consisting only of the relative reference signal and the absolute reference signal. The first module of the processing unit receives the first signal a. The first signal a includes between the two relative reference signals a peak value P corresponding to the passage of the A-type needle of the current blade A1 . By the peak value P REL1 and P REL2 The relative reference signal formed is compared with the peak value P A1 The time offset between enables the calculation of the common pitch angle from the geometric and kinematic parameters of the turbine

[0129] This alternative of the measuring method according to the invention makes it possible to measure the electrical signal over the entire range [θ 1 θ 2 ] to measure the common pitch angle

[0130] Thus, by combining magnetic needles, the invention makes it possible to extend the measurement range of the pitch angle of the blades 22 in a variable pitch angle system. According to different embodiments of the invention and their alternatives, it is possible, for example, to limit the number of needles, improve the measurement accuracy by increasing the measurement values, or optimize the device according to the invention by limiting its redundancy.

[0131] Alternative embodiments of the invention are possible.

[0132] Thus, in a first alternative, the A-type needle 11A has a first shape and the B-type needle 11B has a second shape different from the first shape. This enables the peak value P corresponding to the detection of the A-type needle 11A to be A1 , P A2 and the peak value P corresponding to the detection of the B-type needle 11B B1 , P B2 This shaping makes it easier to identify these peaks.

[0133] Furthermore, in the various embodiments and alternatives described, it has been described that the detection of the type A needle 11A precedes the detection of the type B needle 11B. In other words, the type A needle 11A is detected first after the relative reference magnetic target (or absolute reference magnetic target) is detected. The second alternative includes the opposite configuration, that is, the type B needle 11B is detected first after the relative reference magnetic target (or absolute reference magnetic target) can be detected by changing the geometry of the device.

Claims

1. A device for measuring the pitch angle of a blade of a turbine having a first axis X, the device comprising: a movable wheel (21) centered on said first axis X and provided with a plurality of blades (22) arranged radially about said axis X, each blade (22) having a root (22a) at which said blade (22) is pivotally mounted about a radially pivoted second axis Y, - a fixed frame (80) having an axis X, said fixed frame comprising at least one set of fixed magnetic sensors (12, 12A, 12B), The at least one set of fixed magnetic sensors is perpendicular to the first axis X, - the movable wheel (21) comprises a first magnetic target (13), the first magnetic target being fixed on the movable wheel (21), - each blade (22) has a profile oriented along a third axis Z, a first magnetic needle (11A) attached to the first blade and forming a first angle α with the third axis Z of the first blade, - the first magnetic target (13) serves as a marker for the first blade, - Characterized in that the measuring device comprises a second magnetic needle (11B) attached to a second blade different from the first blade and forming a second angle β with the third axis Z of the second blade, the second angle β being different from the first angle α.

2. The measuring device according to claim 1, characterized in that The second angle β is between α+20 degrees and α+50 degrees.

3. The device according to any one of claims 1 or 2, characterized in that The first angle α is between 70 degrees and 130 degrees.

4. The measuring device according to any one of claims 1 to 3, characterized in that: - the movable wheel (21) comprises a second magnetic target (14) which serves as a marker for the second blade, - the first blade and the second blade are continuous, - the at least one set of fixed magnetic sensors comprises a single set of magnetic sensors (12).

5. A method for measuring the pitch angle of a blade of a turbine, the method being performed by a measuring device according to claim 4, the measuring device further comprising a processing unit, characterized in that: - The method comprises: o Single detection step (E1a): detecting a single magnetic field change by the single set of magnetic sensors (12), or o Multiple detection steps (E1b): detecting a first magnetic field change and a second magnetic field change by the single set of magnetic sensors (12), if the method comprises said single detection step (E1a), said single magnetic field variation corresponds to the passage of said first magnetic needle (11A) or said second magnetic needle (11B) in the vicinity of said single set of sensors, - if the method comprises the plurality of detection steps (E1b), the first magnetic field variation corresponds to the first magnetic needle (11A) passing near the single set of sensors (12), and the second magnetic field variation corresponds to the second magnetic needle (11B) passing near the single set of sensors (12), After said single detection step (E1a) or said plurality of detection steps (E1b), said method comprises a step (E4) of calculating, by said processing unit, the pitch angle on the basis of the electrical signal representative of the variation of the magnetic field.

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