DISTRIBUTOR, PARTICULARLY FOR AN AIRCRAFT TURBINE

Abstract

The invention relates to a distributor (34), particularly for an aircraft turbomachine turbine, comprising a plurality of sectors (40) arranged circumferentially side by side around a principal axis, each sector (40) having an outer annular platform sector (52) and an inner annular platform sector (54) and at least one blade (42) having an upper surface wall and an lower surface wall connected by a leading edge (BA) and a trailing edge (BF) extending respectively between the outer annular platform sector (52) and the inner annular platform sector (54), the trailing edge (BF) having at least one notch (60b) having a bottom (62) offset with respect to a plane (M) passing through the trailing edge (BF) of the blade (42) and perpendicular to the principal axis (Z). Figure 10

Description

Title of the invention: DISTRIBUTOR, IN PARTICULAR FOR A TURBINE OF AN AIRCRAFT TURBOMACHINE Technical field of the invention

[0001] The present invention relates to a distributor for an aircraft turbomachine turbine. The invention also relates to an aircraft turbomachine turbine equipped with such a distributor and to an aircraft turbomachine comprising such a turbine or such a distributor. Technological background

[0002] The [Fig.1] is an axial (or longitudinal) cross-sectional view of an aircraft turbomachine 10 comprising, generally, from upstream to downstream, a fan 12 and several modules, such as a low-pressure compressor 14 followed by a high-pressure compressor 16, a combustion chamber 18, a high-pressure turbine 20 followed by a low-pressure turbine 22, which drive the corresponding low-pressure compressor 14 or high-pressure compressor 16, and a gas ejection system 24.

[0003] The terms "upstream" and "downstream" are defined with respect to the normal direction of gas flow in a flow channel of the turbomachine 10, i.e. from the blower 12 upstream to the gas ejection system 24 downstream.

[0004] A high-pressure body and a low-pressure body are traversed by a primary airflow P and the blower 12 produces a secondary airflow S which circulates in the turbomachine 10, between a casing 11 and an outer jacket 13 of the turbomachine 10, in a cold flow channel 15.

[0005] At the outlet of the gas ejection system 24, the gases from the primary flow P are mixed with the secondary flow S to produce a propulsion force, the secondary flow S here providing the majority of the thrust.

[0006] Figure 2 shows a detailed view of the turbines of turbomachine 10. [Fig. 1]. More specifically, the high-pressure turbine 20 and the low-pressure turbine 22 of the turbomachine 10 typically comprise one or more stages respectively

[0007] - an annular row 30, or crown, of blades or fixed blades carried by the turbine casing 11 and

[0008] - an annular row 32 of blades or blades mounted to rotate around an axis rotation center.

[0009] The fixed blade rings of a turbine are commonly called distributors 34. A distributor 34 diverts and accelerates a gas flow from the chamber of combustion 18 towards the moving turbine blades at an appropriate angle and speed, in order to rotate the moving blades and the turbine rotor.

[0010] In order to facilitate assembly and reduce manufacturing costs, the fixed blade rings are often made in the form of an assembly of angular sectors which are juxtaposed side by side to form a complete ring of fixed blades.

[0011] The distributors 34 of the high-pressure turbine 20 of the turbomachine 10, and consequently the blades that constitute them, are components exposed to very high thermal stresses. They are located at the outlet of the combustion chamber 18 and are therefore traversed by extremely hot gases, which subject them to very high thermal stresses. The distributors 34, particularly the blades, therefore require cooling.

[0012] In order to ensure effective cooling of a distributor blade, it is desirable to have a cooling device which is thermally efficient in order to dissipate a high thermal power by using a moderate air flow.

[0013] One of the most widespread solutions currently used involves employing one or more liners or inserts placed inside the distributor blades. The liners are cooling devices made from multi-perforated sheet metal to cool the inner surface of the blade by means of cooling air impacts. The inner surface of the blade is thus cooled by jet impacts and a forced convection phenomenon between the insert and the inner surface of the blade.

[0014] The terms "cooling air" or "cold air" refer to air whose temperature is lower than the temperature of the gas circulating in the flow path of the turbomachine and which allows the temperature of the elements located in the flow path to be lowered.

[0015] Document FR-A1-2 899 271 describes such a blade cooling device.

[0016] The blades comprise an intrados wall and an extrados wall connected between They are defined by a leading edge BA directed upstream and a trailing edge BF directed downstream.

[0017] However, such high-pressure distributor blades have thin surfaces of significant dimensions, particularly on one half of the extrados wall and at the trailing edge. These are subjected to high compression which can cause damage by buckling or sagging.

[0018] Indeed, when a structure is compressed lengthwise, it tends to bend perpendicularly to the axis of the applied force, due to a phenomenon of elastic instability. Thus, such areas behave like plates undergoing significant deformation perpendicular to the direction of stress.

[0019] Here, one direction of stress is in a plane of the plate, the resulting deformation is therefore out of plane. Such out-of-plane deformation can lead to bulging of the center of the plate, surrounded by cracks.

[0020] Such damage leads to premature ruin of the distribution sector concerned, which must then be replaced.

[0021] Figure 3 represents a sector 40 of a high-pressure distributor having two vanes. 42 of which at least one of the blades 42 has a swelling zone 44 of the extrados wall of the blade 42.

[0022] In addition, another buckling mode was observed on the blades of a high-pressure distributor sector at the trailing edge BF.

[0023] Figure 4 represents such another buckling mode at the trailing edge BF from one of the 42 dawns of sector 40 of distributor 34.

[0024] More specifically, [Fig.4] illustrates such a phenomenon occurring in an area 46 of the trailing edge BF of one of the blades 42 of a sector 40 of the high-pressure distributor.

[0025] Since the trailing edge BF of the high-pressure distributor blades 42 is straight, it can be considered as a plate subjected to compression, stiffened on its three edges, the fourth edge being free in the flow. Being in a very hot zone, it is also subjected to expansion stresses.

[0026] The cooler remainder of the blade 42 prevents such expansion. Furthermore, since the remainder of the blade 42 is more massive, the trailing edge BF absorbs a large part of the expansion stresses up to a certain threshold beyond which such stress becomes sufficient to deform the trailing edge BF by buckling.

[0027] Thus, when the trailing edge BF is in a state of intense compression, it seeks to release the energy related to the compression by deformation leading to an irreversible ultimate deformation state.

[0028] Also, an objective of the present invention is to provide a solution limiting the buckling phenomenon of high-pressure distributors at the trailing edge. Summary of the invention

[0029] A distributor is therefore proposed, particularly for a turbine of an aircraft turbomachine, comprising a plurality of sectors arranged circumferentially next to each other around a main axis. Each sector comprises an outer annular platform sector and an inner annular platform sector and at least one blade having an upper surface wall and an lower surface wall connected to each other by a leading edge and a trailing edge extending respectively between the outer annular platform sector and the inner annular platform sector.

[0030] More particularly, the trailing edge of the blade has at least one notch having a bottom offset from a plane passing through the trailing edge of the distributor blade and perpendicular to the main axis.

[0031] Thus, thanks to the distributor according to the invention, a reduction in the deformation of the trailing edges of the distributor sector blades is ensured. Indeed, the presence of one or more notches makes it possible to reduce the stiffness of the trailing edge, in other words, this makes it possible to reduce the load of the forces experienced by the blade.

[0032] Thus, the invention makes it possible to improve the resistance of the distributor sector blades to the thermomechanical and mechanical stresses suffered by the blades and platforms of the distributor.

[0033] In the present application, the depth of a notch is a dimension measured in a direction perpendicular to the aforementioned plane, which may be parallel to the principal axis. Furthermore, the height of a notch is a dimension measured in the aforementioned plane, preferably oriented radially with respect to the principal axis.

[0034] The distributor, according to the invention, may comprise one or more of the following features, taken individually or in combination with each other:

[0035] - the notch has a substantially straight profile, particularly with the bottom roughly parallel to the plane;

[0036] - the notch has a triangular profile;

[0037] - the notch has a concave profile;

[0038] - the bottom of the notch is defined by a depth whose dimension is greater than a certain height of the notch;

[0039] - the bottom of the notch is defined by a depth whose dimension is less than the height of the notch;

[0040] - the trailing edge has several notches arranged along the trailing edge;

[0041] - the trailing edge has a single notch along the trailing edge;

[0042] - the single notch represents between 50% and 97%, in particular between 75% and 95%, of a radial dimension of the trailing edge extending between the outer annular platform sector and the inner annular platform sector, particularly considered in a trailing edge area downstream of blade slots;

[0043] - the notch has a depth of between 0.6 mm and 6 mm, in particular between 3 mm and 6 mm, in particular between 4.5 mm and 5.7 mm;

[0044] - the bottom of the notch has a depth between 10% and 100%, in particularly between 50% and 95%, in particular between 75% and 95%, of a trailing edge area located downstream of blade slots;

[0045] — the blade slots are cooling slots and have the function of allow a flow of cooling air, in particular from the inside to the outside of the blade.

[0046] The invention also relates to a turbine of an aircraft turbomachine comprising at least one distributor as described above.

[0047] The invention also relates to an aircraft turbomachine comprising at least one distributor as described above and / or a turbine as described above.

[0048] Of course, the different features, variants and / or embodiments of the present invention can be combined with each other in various ways insofar as they are not incompatible or mutually exclusive. Brief description of the figures

[0049] The invention will be better understood and other features and advantages will become apparent from the following detailed description, including embodiments given solely by way of illustration with reference to the accompanying figures, which may serve to complete the understanding of the present invention and the explanation of its implementation and, where appropriate, contribute to its definition, on which:

[0050] Fig. 1 is an axial (or longitudinal) cross-sectional view of a turbomachine to which the invention can be applied;

[0051] [Fig.2] is a detailed view of the turbines of the turbomachine of [Fig.1];

[0052] Figure 3 represents a distributor sector with a swelling area of an extrados wall;

[0053] Fig. 4 represents another buckling mode at the trailing edge of a blade of a distributor sector;

[0054] Fig. 5 represents a schematic perspective view of a distributor sector according to the prior art;

[0055] Fig. 6 represents a schematic cross-sectional view of a blade of the distributor sector of Fig. 5;

[0056] Fig. 7 represents a schematic view of the trailing edge of a vane of the distributor sector of Fig. 5;

[0057] Fig. 8 represents a schematic perspective view of a distributor sector according to a first embodiment of the invention;

[0058] Fig. 9 represents a schematic view of a trailing edge of a vane of the distributor sector of Fig. 8;

[0059] Fig. 10 represents a schematic perspective view of a distributor sector according to a second embodiment of the invention;

[0060] Fig. 11 represents a schematic view of a trailing edge of a blade of the distributor sector of Fig. 10;

[0061] Figure 12 represents a schematic perspective view of a distributor sector according to a third embodiment of the invention; and

[0062] Fig. 13 represents a schematic view of a trailing edge of a blade of the distributor sector of Fig. 12. Detailed description of the invention

[0063] The invention relates to a turbomachine 10 of the type shown in [Fig. 1] and to a turbine thereof. Such a turbine is, for example, a high-pressure turbine 20 as illustrated in [Fig. 2].

[0064] As already indicated, a turbine distributor 34 is conventionally sectorized and formed of several distributor sectors juxtaposed to one another on a circumference centered on an axis of the turbine, i.e. an axis Z of the turbomachine 10 as illustrated in [Fig. 1]. The axis Z is also called the main axis of the distributor 34.

[0065] For convenience, the description and figures that follow relate to a sector 40 of the distributor 34. What is described in relation to sector 40 can thus be applied to all sectors of the distributor 34.

[0066] Fig. 5 represents, by way of example, a schematic perspective view of sector 40 of distributor 34, as generally used.

[0067] Conventionally, such a sector 40 comprises, with respect to the Z axis, an external annular platform sector 52 and an internal annular platform sector 54. The external annular platform sector 52 and the internal annular platform sector 54 delimit between them an annular gas flow channel in the turbine.

[0068] By the terms "lower", "inner" or "internal", it is designated any element whose positioning is close to the Z axis in the radial direction, while by the terms "upper", "outer" or "external", it is designated any element whose positioning is further from the Z axis, in the radial direction, than the lower positioning.

[0069] Thus, the external annular platform sector 52 is radially external to the internal annular platform sector 54. The external annular platform sector 52 and the internal annular platform sector 54 are coaxial.

[0070] It is understood that the external annular platform sector 52 and the internal annular platform sector 54 are configured to form respectively an external annular platform and an internal annular platform within the distributor 34.

[0071] The sector 40 of the distributor 34 further comprises at least one blade 42 which extends between the external annular platform sector 52 and the internal annular platform sector 54.

[0072] The blade 42 extends longitudinally in a first direction, substantially in a radial direction R.

[0073] The blade 42 can, in addition, be defined by a chord 48 which corresponds to the length of the profile, that is to say the distance separating the leading edge BA and the trailing edge BF.

[0074] The blade 42 can be connected to the inner annular platform sector 52 and to the outer annular platform sector 54 by a connecting fillet 43a, 43b or connection all around the blade 42 from the leading edge BA to the trailing edge BF on the lower surface 56 and the upper surface 58.

[0075] The blade 42 is hollow through a height from which cooling air circulates. The cooling air comes from a supply chamber (not shown) and is, for example, the air taken from the outlet of the high-pressure compressor 16.

[0076] [Fig.6] illustrates a schematic cross-sectional view of the blade 42 of sector 40 of [Fig.5]. The blade 42 comprises an intrados wall 56 and an extrados wall 58 connected to each other by a leading edge BA directed upstream and a trailing edge BF directed downstream.

[0077] Fig. 7 represents a schematic view of the trailing edge BF of the blade 42 of Fig. 5 as commonly used.

[0078] Figures 8 to 13 represent different embodiments according to the invention.

[0079] In the embodiments according to the invention shown in figures 8 to 13, the trailing edge BF has at least one notch 60a, 60b, 60c.

[0080] In this description, "notch" means a cutout in the trailing edge BF.

[0081] The notch 60a, 60b, 60c further includes a bottom 62 offset with respect to a plane M passing through the trailing edge BF of the blade 42 of the distributor 34 and perpendicular to the main axis Z of the distributor 34, i.e. the axis of the turbomachine 10.

[0082] The blade 42 may include blade cooling means communicating with the outside of the blade 42 by means of slots 50 arranged in the vicinity of the trailing edge BF. These slots 50 are cooling slots and their function is to allow a flow of cooling air to pass through, in particular from the inside to the outside of the blade.

[0083] Alternatively or in addition, the notch 60a, 60b, 60c of the trailing edge BF may have a depth between 10% and 100%, in particular between 50% and 95%, in particular between 75% and 95%, of a zone A of the trailing edge BF located downstream of the slots 50 of the distributor 34 of the blade 42.

[0084] In particular, the notch 60a, 60b, 60c of the trailing edge BF can therefore be offset from the plane M by a distance whose value is between 10% and 100%, in particular between 50% and 95%, in particular between 75% and 95%, of a zone A of the trailing edge BF located downstream of the ejection slots 50 of the blade 42.

[0085] More specifically, the notch 60a, 60b, 60c of the trailing edge BF can have a depth of between 0.6 mm and 6 mm, in particular between 3 mm and 6 mm, in particular between 4.5 mm and 5.7 mm.

[0086] Advantageously, the notch 60a, 60b, 60c can have a different shape and / or profile. The choice of shape and / or profile depends on the stress distribution in the trailing edge BF and is determined beforehand during the design phase of the distributor 34.

[0087] Indeed, the shape and / or profile can influence the aerodynamics and / or the integration of the desired part. For example, several consecutive notches along the trailing edge BF help to maintain a distribution of the airflow in the duct.

[0088] Furthermore, the notch 60a, 60b, 60c increases the threshold of the first buckling mode. In other words, this provides better thermomechanical resistance to the trailing edge BF.

[0089] Figures 8 and 9 represent schematic perspective views of sector 40 of distributor 34 and trailing edge BF of blade 42 of sector 40 of distributor 34 of [Fig.8] according to a first embodiment of the invention.

[0090] In particular, Figures 8 and 9 illustrate the first embodiment of the invention in which the trailing edge BF comprises at least one notch 60a having a substantially straight profile. Alternatively, the notch 60a with a substantially straight profile is unique. According to the first embodiment of the invention, the bottom 62 of the notch 60a may be substantially parallel to the plane M.

[0091] The single notch can represent between 50% and 97%, in particular between 75% and 95%, of a trailing edge height BF, in particular considered downstream of the slots of the distributor 34, corresponding to a radial dimension, with respect to the principal axis Z, of the trailing edge BF extending between the external annular platform sector 52 and the internal annular platform sector 54.

[0092] Figures 10 and 11 represent schematic perspective views of sector 40 of distributor 34 and trailing edge BF of blade 42 of sector 40 of distributor 34 of [Fig. 10] according to a second embodiment according to the invention.

[0093] More particularly, figures 10 and 11 illustrate the second embodiment according to the invention in which the trailing edge BF comprises at least one notch 60b having a triangular profile.

[0094] The trailing edge BF may have several notches 60b with a consecutive triangular profile along the trailing edge BF.

[0095] In the example shown in Figures 10 and 11, the trailing edge BF has two notches 60b with a triangular profile. Alternatively, and not shown, the trailing edge BF may have more than two notches 60b with a triangular profile. In general, the number of notches 60b can vary according to the desired mechanical properties, as described above.

[0096] Alternatively, the trailing edge BF may have at least two notches 60b having different triangular profiles. Thus, a first notch 60b may have a different triangular profile than a second notch 60b. In other words, the shape of the triangular profile may differ from one notch 60b to another.

[0097] In the case of the notch 60b with a triangular profile according to the second embodiment, the bottom 62 of the notch 60b can be defined by a depth p whose dimension is less than or equal to a height h of the notch 60b.

[0098] The height h designates an opening of the notch 60b. The height h is preferably oriented radially with respect to the principal axis Z. Furthermore, the depth p is a dimension that extends perpendicularly to the height h.

[0099] In an alternative, not shown, the depth pa has a dimension which is greater than or equal to the height h of the notch 60b with a triangular profile according to the second embodiment.

[0100] In the particular case where the trailing edge BF has several consecutive notches 60b, the triangular profile has hollows 64 and at least one apex 66. The hollows 64 can be considered as the bottom 62. The apex 66 can be located in the plane M.

[0101] Alternatively, the vertex 66 can be offset from the plane M. It is understood that, in this case, the vertex 66 is located, with respect to the plane M, at a distance whose non-zero value is strictly less than the value of the depth p of the bottom 62.

[0102] In such an embodiment, the triangular profile notches 60b may be contiguous, so that the apex 66 may form a point. Alternatively, the triangular profile notches 60b may be spaced apart, so that the apex 66 may form a flat surface.

[0103] Figures 12 and 13 represent schematic perspective views of sector 40 of distributor 34 and trailing edge BF of blade 42 of sector 40 of distributor 34 of [Fig. 10] a third embodiment according to the invention.

[0104] More particularly, figures 12 and 13 illustrate the third embodiment according to the invention in which the trailing edge BF has at least one notch 60c having a concave profile.

[0105] The term “concave” refers to a rounded shape, for example in the form of an arc of a circle or an elliptical shape.

[0106] The profile of the 60c notch with a concave profile can also take the form of a "spline", an Anglo-Saxon term designating the shape of a function defined piecewise by polynomials.

[0107] The trailing edge BF may have several 60c notches with a consecutive concave profile along the trailing edge BF.

[0108] In the example shown in Figures 12 and 13, the trailing edge BF has three 60c notches with a concave profile. Alternatively, and not shown, the trailing edge BF may have fewer or more than three 60c notches with a concave profile. Generally, the number of 60c notches can vary according to the desired mechanical properties, as described above.

[0109] Alternatively, the trailing edge BF may have at least two notches 60c having different concave profiles. Thus, a first notch 60c may have a different concave profile than a second notch 60c. In other words, the shape of the concave profile may differ from one notch 60c to another.

[0110] In the case of the notch 60c with a concave profile according to the third embodiment, the bottom 62 of the notch 60c can be defined by a depth p whose dimension is greater than or equal to a height h of the notch 60c.

[0111] The height h designates an opening of the notch 60c. The height h is preferably oriented radially with respect to the principal axis Z. Furthermore, the depth p is a dimension that extends perpendicularly to the height h.

[0112] In an alternative, not shown, the depth pa a dimension which is less than or equal to the height h of the notch 60c with a concave profile according to the third embodiment.

[0113] In the particular case where the trailing edge BF has several consecutive notches 60c, the concave profile has hollows 64 and at least one apex 66. The hollows 64 can be considered as the bottom 62. The apex 66 can be located in the plane M.

[0114] Alternatively, the vertex 66 can be offset from the plane M. It is understood that, in this case, the vertex 66 is located, with respect to the plane M, at a distance whose non-zero value is strictly less than the value of the depth p of the bottom 62.

[0115] In such an embodiment, the notches 60c with concave profile may be spaced apart, so that the apex 66 may form a flat surface. Alternatively, the notches 60c with concave profile may be contiguous, so that the apex 66 may form a point.

[0116] The distributor 34, as described above, allows a reduction of the deformation of the trailing edges BF of the blades 42 of the sectors 40 of the distributor 34. Indeed, the presence of one or more notches 60a, 60b, 60c makes it possible to reduce the stiffness of the trailing edge BF, in other words it makes it possible to reduce the load of the forces suffered by the blade 42.

[0117] Another advantage of the invention is to allow an improvement in the resistance of the vanes 42 of the distributor 34 to the thermomechanical and mechanical stresses suffered by the vanes 42 and the platforms of the distributor 34.

[0118] Another advantage of the invention is that it allows for simplified design. Indeed, the distributor 34 according to the invention does not require modification of the aerodynamic profile of the vanes 42, which ensures the performance of the part while diverting its load to limit the load on the upper surface. Thus, the cooling efficiency, which impacts both engine performance and the durability of the part by maintaining it at an acceptable temperature, is preserved.

Claims

Demands

1. Distributor (34), in particular for a turbine (20) of an aircraft turbomachine (10), comprising a plurality of sectors (40) arranged circumferentially next to each other around a principal axis (Z), each sector (40) comprising - an outer annular platform sector (52), - an inner annular platform sector (54) and - at least one hollow blade (42) having an upper surface wall (58) and an lower surface wall (56) connected to each other by a leading edge (BA) and a trailing edge (BF) extending respectively between the outer annular platform sector (52) and the inner annular platform sector (54), said at least one blade comprising cooling slots (50) disposed in the vicinity of the trailing edge, said cooling slots allowing a flow of cooling air from the inside to the outside of the blade,characterized in that the trailing edge (BF) of the blade (42) comprises at least one notch (60a, 60b, 60c) having a bottom (62) offset with respect to a plane (M) passing through the trailing edge (BF) of the blade (42) of the distributor (34) and perpendicular to the main axis (Z), said bottom (62) of the notch having a depth between 10% and 100% of an area (A) of the trailing edge (BF) located downstream of said slots (50) of the blade (42).

2. Distributor (34) according to claim 1, wherein the notch (60a) has a substantially straight profile, in particular with the bottom (62) substantially parallel to the plane (M).

3. Distributor (34) according to claim 1, wherein the notch (60b) has a triangular profile.

4. Distributor (34) according to claim 1, wherein the notch (60c) has a concave profile.

5. Distributor (34) according to any one of the preceding claims, wherein the bottom (62) of the notch (60b, 60c) is defined by a depth (p) whose dimension is greater than a height (h) of the notch (60b, 60c).

6. Distributor (34) according to any one of claims 1 to 4, wherein the bottom (62) of the notch (60b, 60c) is defined by a depth (p) whose dimension is less than a height (h) of the notch (60b, 60c).

7. Distributor (34) according to any one of the preceding claims, wherein the trailing edge (BF) has several notches (60a, 60b, 60c) arranged along the trailing edge (BF).

8. Distributor (34) according to any one of claims 1 to 6, wherein the trailing edge (BF) has a single notch (60a, 60b, 60c) along the trailing edge (BF).

9. Distributor (34) according to claim 8, wherein the single notch (60a) represents between 50% and 97%, in particular between 75% and 95%, of a radial dimension of the trailing edge (BF) extending between the outer annular platform sector (52) and the inner annular platform sector (54).

10. Distributor (34) according to any one of the preceding claims, wherein the notch (60a, 60b, 60c) has a depth between 0.6 mm and 6 mm, in particular between 3 mm and 6 mm, in particular between 4.5 mm and 5.7 mm.

11. Distributor (34) according to any one of claims 1 to 8, wherein the bottom (62) of the notch has a depth of between 50% and 95%, in particular between 75% and 95%, of an area (A) of the trailing edge (BF) located downstream of blade slots (42).

12. Turbine (20) of an aircraft turbomachine, characterized in that it comprises at least one distributor according to any one of the preceding claims.

13. Aircraft turbomachine (10), characterized in that it comprises at least one turbine distributor (34) according to any one of claims 1 to 11 and / or a turbine (20) according to claim 12.

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