GB2587640A

GB2587640A - Coupling liquid housing

Info

Publication number: GB2587640A
Application number: GB1914237.1A
Authority: GB
Inventors: Collison Ian; Sims Brett; Stone Paul; Johnson Stephen
Original assignee: Rolls Royce PLC
Current assignee: Rolls Royce PLC
Priority date: 2019-10-02
Filing date: 2019-10-02
Publication date: 2021-04-07
Also published as: GB201914237D0

Abstract

A coupling liquid housing for use with an ultrasonic transducer to inspect a surface (34, fig 3) of a component (e.g. a blade (13, fig 1) of a gas turbine engine (10, fig 1)) by local immersion ultrasonic testing includes a sleeve 23 with a first end 24 for receiving the ultrasonic transducer and a second end 25 with a flange 27 extending radially outwards from the sleeve 23. The flange 27 includes a first planar surface 271 which is held in a sealed arrangement against the inspected surface (34, fig 3). The interior of the sleeve 23 forms a reservoir for holding ultrasonic coupling liquid. The flange 27 may be flexible and contour against the shape of the surface 34. The housing may also include a compressive collar 28 which deforms under a force to hold the sealing surface 271 in place and a rigid jacket 32 to apply a force to the compressive collar 28. The flange 27 acts to prevent leakage of ultrasonic coupling liquid.

Description

COUPLING LIQUID HOUSING

Field of the disclosure

The present disclosure concerns a device to be used with an ultrasonic transducer to inspect a surface of a component by local immersion ultrasonic testing, in particular a housing for retaining an ultrasonic coupling liquid against the surface of the component in a sealed manner. The present disclosure is also concerned with a corresponding method of using the device to perform local immersion ultrasonic testing.

Background

In the field of aeronautical engineering, it is important to maintain the structural integrity of components of a gas turbine engine, such as the fan blades, in order to avoid structural failure of those components and to ensure their safe and efficient operation. Accordingly, a number of inspection techniques have been developed to identify structural defects in the material of the components, so that corrective action may be taken.

One such inspection technique is known in the art as "ultrasonic testing", where the structural integrity of a component is inspected by subjecting its surface to ultrasonic wave energy and analysing the ultrasonic wave energy after interaction with the surface of the component. In reflection based systems, an ultrasonic transducer transmits ultrasonic wave energy towards the component and detects the ultrasonic wave energy following reflection off the surface of the component. In attenuation based systems, however, an ultrasonic transducer transmits ultrasonic wave energy towards the component and a separate receiver detects the amount of ultrasonic wave energy that has travelled through the component. In both cases, the detected signal carries information regarding imperfections on at least the surface of the component, which can be used by a computer processor to diagnose the structural integrity of the component.

In order to provide effective transfer of the ultrasonic wave energy from the transducer to the component under inspection, the transducer is usually coupled to the component by an ultrasonic coupling liquid (such as water or an ultrasonic gel) through which the ultrasonic wave energy is to be transmitted in a consistent, predictable manner. While the component may be submerged in a bath of coupling fluid for this purpose, it is known to couple the transducer to the surface of the component in a manner known as "local immersion", wherein only a localised region on the surface of the component is in contact with a coupling fluid that couples the ultrasonic transducer. This is achieved, typically, by providing an open ended tube that is filled with a coupling liquid when it is placed on the surface to be inspected. An ultrasonic transducer is connected to an end of the tube that is remote from the end which is in contact with the surface to be investigated. In use, the ultrasonic wave energy is transmitted from the transducer through the coupling liquid along a fluid path defined by the tube towards the surface of the component. In order to perform a full scan of the surface, the tube is typically scanned across the entire surface of the component.

A disadvantage of the conventional local immersion arrangement is that the 20 coupling liquid may leak from the open end of the tube that is in contact with the surface, particularly when the tube is passed across a curved surface of the component under inspection.

It is therefore desired to provide a housing for retaining an ultrasonic coupling 25 liquid against a local region on the surface of the component in a sealed manner.

Summary of the disclosure

According to a first aspect there is provided a coupling liquid housing for use with an ultrasonic transducer to inspect a surface of a component by local immersion ultrasonic testing. The coupling liquid housing comprises: a sleeve extending about a central longitudinal axis and having a first longitudinal end for receiving the ultrasonic transducer; and a flange extending radially outwards from a second longitudinal end of the sleeve. The flange has a first planar surface which is suitable for being held in a sealed arrangement against the surface of the component, such that an interior of the sleeve defines a reservoir for retaining an ultrasonic coupling liquid against the surface of the component.

The flange may be formed of a resiliently flexible material that is contourable to conform to the shape of the surface of the component to be inspected.

The flange may be in the form of an annular ring.

The coupling liquid housing may further comprise a compressive collar that surrounds the sleeve. The compressive collar may be configured to resiliently deform under an applied force, so as to hold the first planar surface in the sealed arrangement against the surface of the component.

The compressive collar may be in contact with a second planar surface of the flange on an opposite side of the flange to the first planar surface. The compressive collar may be configured to engage the second planar surface by resiliently deforming under a force applied by a user, so as to hold the first planar surface in the sealed arrangement against the surface of the component.

The compressive collar may comprise a protruding member extending longitudinally from the second planar surface. The protruding member may be in the shape of a curved surface of revolution about the central longitudinal axis.

The protruding member may have a plurality of slots arranged in a uniform manner in an arc about the central longitudinal axis.

The compressive collar may comprise an annular ring extending in a circumferential arc about the central longitudinal axis. The annular ring may be 30 spaced from the flange in the longitudinal direction by a plurality of resiliently flexible arms that are arranged along an arc about the central longitudinal axis.

The compressive collar may comprise an annular ring extending in a circumferential arc about the central longitudinal axis. The annular ring may be spaced from the flange in the longitudinal direction by a single, resiliently flexible arm that extends along an arc about the central longitudinal axis substantially entirely.

A rigid jacket may surround the sleeve and may be slideable along the sleeve in the longitudinal direction. The compressive collar may be configured to be compressed by movement of the rigid jacket under an applied force.

According to another aspect, there is provided a method of inspecting a surface of a component by local immersion ultrasonic testing, the method comprising: placing the coupling liquid housing of any preceding statement onto a portion of the surface of the component to be inspected; applying a force on the flange in order to form a seal at the interface between the first planar surface of the flange and the surface of the component, such that an interior of the sleeve defines a reservoir for retaining an ultrasonic coupling liquid against the surface of the component; inserting an ultrasonic transducer into the sleeve through the first end of the sleeve; adding a coupling liquid into the sleeve so as to immerse the ultrasonic transducer in the coupling liquid; activating the ultrasonic transducer so as to insonate the surface of the component via the coupling liquid; and detecting ultrasonic wave energy following interaction with the surface of the component.

The skilled person will appreciate that except where mutually exclusive, a feature described in relation to any one of the above aspects may be applied mutatis mutandis to any other aspect. Furthermore except where mutually exclusive any feature described herein may be applied to any aspect and/or combined with any other feature described herein.

Brief description of the drawings

Embodiments will now be described by way of example only, with reference to the Figures, in which: Figure 1 is a sectional side view of a gas turbine engine; Figure 2 shows two images of a coupling liquid housing, in accordance with a first embodiment of the technology described herein; Figure 3 is an image of the coupling liquid housing of Figure 2 being used 5 together with an ultrasonic transducer assembly; Figure 4 is a flow chart schematically illustrating a method of using the coupling liquid housing and ultrasonic transducer assembly of Figure 3 to perform a local immersion ultrasonic test; Figure 5 is an image of a coupling liquid housing according to a second embodiment of the technology described herein; and Figure 6 is an image of a coupling liquid housing according to a third 15 embodiment of the technology described herein.

It will be appreciated that like reference numerals are used in the drawings to label like features of the technology described herein.

Detailed description

With reference to Figure 1, a gas turbine engine is generally indicated at 10, having a principal and rotational axis 11. The engine 10 comprises, in axial flow series, an air intake 12, a propulsive fan 13, an intermediate pressure compressor 14, a high-pressure compressor 15, combustion equipment 16, a high-pressure turbine 17, an intermediate pressure turbine 18, a low-pressure turbine 19 and an exhaust nozzle 20. A nacelle 21 generally surrounds the engine 10 and defines both the intake 12 and the exhaust nozzle 20.

The gas turbine engine 10 works in the conventional manner so that air entering the intake 12 is accelerated by the fan 13 to produce two air flows: a first air flow into the intermediate pressure compressor 14 and a second air flow which passes through a bypass duct 22 to provide propulsive thrust. The intermediate pressure compressor 14 compresses the air flow directed into it before delivering that air to the high pressure compressor 15 where further compression takes place.

The compressed air exhausted from the high-pressure compressor 15 is 5 directed into the combustion equipment 16 where it is mixed with fuel and the mixture combusted. The resultant hot combustion products then expand through, and thereby drive the high, intermediate and low-pressure turbines 17, 18, 19 before being exhausted through the nozzle 20 to provide additional propulsive thrust. The high 17, intermediate 18 and low 19 pressure turbines 10 drive respectively the high pressure compressor 15, intermediate pressure compressor 14 and fan 13, each by suitable interconnecting shaft.

Other gas turbine engines to which the present disclosure may be applied may have alternative configurations. By way of example such engines may have an alternative number of interconnecting shafts (e.g. two) and/or an alternative number of compressors and/or turbines. Further the engine may comprise a gearbox provided in the drive train from a turbine to a compressor and/or fan.

It is known in the art that cracking may form on the surfaces of various components of gas turbine engines, such as the blades of the propulsive fan 13 of the engine 10 described above with respect to Figure 1. Accordingly, such components of a gas turbine engine are often subjected to local immersion ultrasonic testing to ensure that the structural integrity of the components are maintained at safe levels. According to previously considered arrangements, this is achieved by providing a coupling liquid housing which is in the form of a tube having a first end, which is connected to an ultrasonic transducer, and a second, open end, which is to be closed when the tube is brought into abutment with the surface of a component to be inspected. However, conventional coupling liquid housings are prone to leakage of the coupling liquid from the tube, especially when held against curved surfaces, which can reduce the extent of coupling between the ultrasonic transducer and the component surface and thus the accuracy of the detected signals and resulting analysis.

The present disclosure provides a coupling liquid housing which is capable of forming a stronger seal against both planar and curved surfaces of a component to be inspected, as will now be described with respect to Figures 2 to 4.

Figure 2 shows two images of a coupling liquid housing, in accordance with a first embodiment of the technology described herein.

The coupling liquid housing includes an open ended sleeve 23 which is elongate about a central longitudinal axis 26. The sleeve 23 is in the form of a wall that is shaped to define a substantially tubular structure, i.e. a hollow cylinder of circular cross-section, where the tubular wall surrounds the central longitudinal axis 26 in a circumferential arc direction. The sleeve 23, particularly the tubular wall thereof, has a longitudinal extent between a first longitudinal end 24 and a second longitudinal end 25 of the sleeve 23, which are at opposite sides (distal from the centre) of the sleeve 23 in the longitudinal axis 26.

It will be appreciated that the sleeve need not be tubular in structure, and may instead have a substantially square shape in transverse cross-section, for example.

An interior of the sleeve 23 is hollow to define a space within the sleeve 23 that is suitable for receiving an ultrasonic transducer (not shown), which may be inserted through the first end 24 of the sleeve 23. The sleeve 23 has an internal diameter and a longitudinal extent that is of a suitable size to enable the ultrasonic transducer to be entirely contained within space inside the sleeve 23, when received therein.

At the second longitudinal end 25 of the sleeve 23, there is a flange portion 27 that extends radially outwards from the sleeve 23, perpendicularly to the longitudinal axis 26. The flange portion 27 has an annular profile formed by two circular (or disc shaped) planar surfaces: a first planar surface 271 which faces away from the longitudinal centre of the sleeve 23; and a second planar surface 272 which faces towards the longitudinal centre of the sleeve 23. The planar surfaces 271 and 272 of the flange portion 27 extend along an arc that surrounds the sleeve 23 entirely.

In use, the first planar surface 271 of the flange portion 27 is brought into contact 5 with, and held against, a surface of the component to be inspected (not shown), such that the second end 25 of the sleeve is closed and substantially sealed from leakage by the surface of the component. In this manner, the interior of the sleeve 23 (i.e. the internal surfaces of the tubular wall) and the surface of the component together form a reservoir for retaining a coupling liquid against the 10 surface of the component. In particular, a coupling liquid, such as water, will be pumped into the reservoir from the first end 24 of the coupling liquid housing and retained therein by the seal that is formed at the interface between the first planar surface 271 and the surface of the component.

By providing a flange portion 27, the second end 25 of the sleeve 23 can be brought into abutment with the surface of a component in a manner that increases the contact area and thus the extent of sealing at the interface between the surface and the coupling liquid housing. This is particularly true as compared to previously considered arrangements in which the housing is in the form of a tubular structure only, i.e. without a flange portion. Accordingly, the coupling fluid housing of the technology described herein may be advantageous in that it reduces the amount of leakage of coupling fluid from the reservoir within the housing, thereby enhancing the coupling between the ultrasonic transducer and component surface.

In embodiments, the flange portion 27 is formed of a resiliently flexible material, such as thermoplastic polyurethane, e.g. commercially available TPU 95A, which is contourable to the shape of the surface of the component under an applied force, but capable of regaining its original shape after the applied force is removed. In particular, the application of a force on the second planar surface 272 of the flange portion 27 will cause the first and second planar surfaces 271 and 272 to deform from a planar shape to a shape that instead conforms to the shape of the surface to be inspected. This may be advantageous in that it can increase the extent of sealing between the coupling liquid housing (the first planar surface 271) and the surface of the component to be inspected, even in circumstances where the surface is curved.

Although the flange portion 27 may adequately seal the coupling liquid housing 5 to the surface to be inspected, in some cases the extent of sealing may be improved if the force is applied to the flange portion 27 in a more uniformly distributed manner in the circumferential direction. This is achieved, in embodiments, by providing the coupling liquid housing with a compressive collar 28 that is configured to resiliently deform under an applied force so as to transfer 10 the applied force uniformly across the second planar surface 272 of the flange 27 in order to hold the first planar surface 271 in the sealed arrangement against the surface of the component. The compressive collar 28 may be connected as an integral part of the housing or may be a separate element for use with the housing.

In the illustrated embodiment of Figure 2, the compressive collar 28 is in the form of a protruding member 29 that extends from the second planar surface 272 of the flange portion 27 towards the longitudinal centre of the sleeve 23. The protruding member 29 extends along a circumferential arc that surrounds the sleeve 23 entirely. The protruding member 29 is spaced radially outwards of the sleeve 23 such that a gap 30 is formed therebetween, to allow movement of the protruding member 29 relative to the sleeve 23.

The protruding member 29 is in the form of a curved surface of revolution about the longitudinal axis 26. In that regard, the protruding member 29 has a concave surface on a side that faces the sleeve 23 and a convex surface on a side of the protruding member 29 that faces away from the sleeve 23. However, in other embodiment the concave surface may be on a side that faces away from the sleeve 23 and the convex surface may be on a side that faces towards the sleeve 23. The curves surfaces serve to increase the flexibility of the protruding member 29 and act as a spring that would provide resilience that causes the member 29 to return to its original shape after deformation. In that regard, the compressive collar 28 is also formed of resiliently flexible material, such as thermoplastic polyurethane, e.g. TPU 95A.

The curved surface has a plurality of holes or slots 31 that extend radially through the protruding member 29, where each slot 31 is elongate in the longitudinal direction. The slots may provide the protruding member 29 with sufficient flexibility to allow for deformation of the protruding member 29 in the longitudinal direction, while resisting deformation in the radial direction. Further, the plurality of slots 31 are arranged in a uniform manner along a circumferential arc about the central longitudinal axis 26, in that neighbouring slots 31 are separated by an equidistant pitch (measured as an arc length), to allow for a uniform distribution of stress about the protruding portion 28 and the flange 27 in the circumferential direction. The slots 32 may allow at least some local deformation of the collar to force the flange 27 to conform to the shape of the surface to be inspected.

It will be appreciated that although the sleeve 23, flange portion 27 and compressive collar 28 (or rather the protruding member 29) have been described above as separate elements of the overall coupling fluid housing, one or more or all of those elements may be connected as an integral part. For example, the sleeve 23, flange portion 27 and compressive collar 28 may be formed as a single, one-piece unit, e.g. by using additive manufacturing (e.g. 3D printing) techniques known in the art. In particular, the sleeve 23, flange portion 27 and compressive collar 28 may be formed as a single piece of thermoplastic polyurethane material, e.g. commercially available TPU 95A.

The coupling liquid housing may be provided with a rigid jacket 32 which is supported on the compressive collar 28, as shown in Figure 2. The rigid jacket 32 of the illustrated embodiment is in the form of a disc having an inner diameter that is larger than the outer diameter of the sleeve 23, but less than the outer diameter of the flange portion 27, such that it is slidingly received by the sleeve 23 and moveable along the sleeve 23 in the longitudinal direction. The rigid disc 32 has two circumferentially extending regions, each of which includes an ergonomic grip 33 for allowing a user to apply a force to the disc 32 in the longitudinal direction.

In use, the rigid jacket 32 is moveable to compress the compressive collar 28, where the rigidity of the jacket 32 enables the force to be applied more uniformly across the compression collar in the circumferential direction. This may further increase the extent of sealing at the interface between the first planar surface 271 of the flange portion 27 and the surface of the component to be investigated.

Figure 3 is an image of the coupling liquid housing of Figure 2 together with an ultrasonic transducer assembly. Figure 4 is a flow chart schematically illustrating a method of using the coupling liquid housing and ultrasonic transducer assembly of Figure 3 to perform a local immersion ultrasonic test. Accordingly, the method of performing a local immersion ultrasonic test in line with the technology described herein will now be described with respect to both of those Figures in combination.

The method begins at step 100 of Figure 4, at which the coupling liquid housing described above with respect to Figure 2 is placed into a position on a local portion of a surface 34 of the component to be inspected. In the illustrated example of Figure 3, the component is in the form of a fan blade of a gas turbine engine.

The coupling liquid housing is placed on the surface 34 of the fan blade so that the first planar surface (see reference 271 of Figure 2) of the flange portion 27 engages and is in contact with (abuts) the blade surface 34 such that the blade surface 34 closes the second end (25) of the sleeve 23. In this position, the internal profile of the sleeve and the portion of the surface 34 on which the housing is mounted together define a reservoir for retaining a coupling liquid against the blade surface 34.

At step 200, when the coupling housing is in position on the surface 34, an ultrasonic transducer assembly 35 is inserted into a space defined by the interior profile of the sleeve 23, such that it sits within the reservoir that is suitable for retaining a coupling fluid. As shown in Figure 3, the assembly 35 is received through the first end 24 of the sleeve, opposite a second end which is closed by the surface 24.

The ultrasonic transducer assembly 35 includes an ultrasonic transducer (not shown), which may be a single transducer element or an array of plural transducer elements, which is freely manoeuvrable within the sleeve by the use of a handle 36 which can be manipulated by the hand 37 of a user. The ultrasonic transducer or array is coupled to a signal generator (not shown) via suitable cabling 38. The ultrasonic transducer itself may be supported at a suitable working angle with respect to the blade surface 34 by a wedge or block, which sits on the surface 34 of the fan blade.

At step 300, while the ultrasonic transducer assembly 36 is located in place on a portion of the surface 34, the user applies a force on the second planar surface (see reference 272 of Figure 2) of the flange portion 27. The force may be applied manually by the hand 39 of the user 45. In particular, and as described above, the user applies a force on the rigid jacket 32 of the coupling liquid housing in a direction towards the surface 34 of the fan blade, where the force is then transferred uniformly across the second planar surface (272) of the flange portion 27 by the compressive collar (see reference 28 of Figure 2). In this manner, a seal is formed at the interface between the first planar surface (271) of the flange 27 and the surface 34 of the fan blade. Further, under the applied force the flange portion 37 deforms from a substantially planar surface so as to conform to the shape of the surface 34 of the fan blade, which will be curved.

At step 400, and at the same time as a force is applied to seal the first planar surface of the flange portion 27 to the surface 34 of the fan blade, a coupling liquid (not shown) is introduced into the sleeve 23 in the space within which the ultrasonic transducer assembly 35 is housed, so as to immerse the ultrasonic transducer in the coupling liquid. This is done by pumping the coupling fluid from a source or reservoir of coupling liquid via a liquid supply line 40. By immersing the ultrasonic transducer in the coupling liquid, the ultrasonic transducer will be ultrasonically coupled to the surface 34 of the blade, to facilitate an efficient and consistent transfer of ultrasonic wave energy therebetween. The coupling liquid may be continuously pumped into the water housing, and the rate at which this is done may vary on a case-by-case basis. In an embodiment, the coupling fluid is pumped at a constant flow of 2 litres per minute.

It will be appreciated here that by applying pressure to the flange portion 27 via the rigid jacket 32 to form a seal, the coupling liquid is prevented from leaking from the space within the sleeve 23 at the interface between the first planar surface of the flange portion 27 and the surface 34 of the fan blade. In some arrangements, however, excess coupling liquid may be allowed to exit the sleeve through the first end 24 thereof.

At step 500, the ultrasonic transducer is activated to insonate the surface 34 of the fan blade. In particular, the signal generator operates to generate ultrasonic wave energy that is supplied via cabling 38 to the transducer, which then transmits the ultrasonic wave energy to the surface 34 of the fan blade via the coupling liquid. The ultrasonic wave signal that is generated by the signal generator and transmitted by the transducer may have any frequency within the ultrasonic range that is known in the art to be suitable for performing ultrasonic testing. In this particular example, the frequency of the ultrasonic signal is 10MHz.

At step 600, the ultrasonic wave energy is detected following its interaction with the surface 34 of the component, and this may be done using conventional methods known in the art. The coupling liquid housing is then scanned or moved by the user across the surface 34 of the fan blade, in order to ultrasonically test other local portions of the surface 34. Under the application of a constant force on the rigid jacket 32 during the scanning motion, the seal between the flange portion 27 and the surface 34 of the fan blade will be maintained, as the flange portion 27 will continue to conform to the shape of the other portions on the surface 34 of the fan blade. After step 600 has been completed, the detected signal may be subjected to a post-detection analysis to determine the structural integrity of the fan blade, as is known in the art.

Although the compressive collar 28 has been described above as being in the form of a curved surface of revolution about the longitudinal axis, other forms are equally possible and desirable.

Figure 5 is an image of a coupling liquid housing according to a second embodiment in which the compressive collar 28 has a different structure, as will now be described.

In the embodiment illustrated in Figure 5, the coupling liquid housing is substantially the same as that described above with respect to Figures 2 to 4 (and for that reason like features are given like reference numerals in the drawings). For example, the housing comprises the sleeve 23 and flange portion 27 described above. The coupling liquid housing of the Figure 5 embodiment differs from that of Figures 3 to 4, however, in that the compressive collar 28 is in the form of an annular ring 41 that is centred on the central longitudinal axis (not shown) of the sleeve 23 and extends in a circumferential arc about the axis. The inner diameter of the ring 41 is larger than the outer diameter of the sleeve 23 such that the ring 41 is positioned to define a radial gap 43 between the ring 41 and the sleeve 23, to allow movement of the ring 41 relative to the sleeve 23.

The annular ring 41 is connected to the second planar surface 272 of the flange portion 27 by a plurality of arms 42 that extend longitudinally such that the annular ring 41 is spaced from the second planar surface 272 in the longitudinal direction. The arms 42 are resiliently flexible (and in that regard may be formed of a thermoplastic polyurethane material), such that they are resilient enough to transfer forces substantially evenly, but still allow some local deformation to force the flange portion 27 to conform to the shape of the surface. The plurality of arms 42 are disposed at oblique angles to the second planar surface 272 of the flange portion.

The plurality of arms 42 are arranged along an arc about the central axis 26 on the second planar surface 272 with an equidistant pitch between neighbouring arms 42. In this way, a force applied to the annular ring 41 may be distributed more evenly about the second planar surface 27 of the flange portion 27. The pitch between neighbouring arms 42 may have an arc length that extends by an angle of 15 degrees or less about the longitudinal axis, to facilitate a more uniform force transfer.

Figure 6 is an image of a coupling liquid housing according to an embodiment in which the compressive collar 28 has a different structure, as will now be described. The compressive collar 28, in this embodiment, is substantially the same as that described above with respect to Figure 5 (and for that reason like features are given like reference numerals in the drawings). For example, the compressive collar 28 that includes an annular ring 41 that is connected to the second planar surface 272 of the flange portion and is spaced radially outwards of the sleeve 23 to allow movement of the ring 41 relative to the sleeve 23.

However, the compressive collar 28 of the Figure 6 embodiment differs from that of Figure 5 in that the annular ring 41 is connected to and spaced from the second planar surface 272 in the longitudinal direction by a single arm 44 that extends along a circumferential arc that surrounds the central axis 26 substantially entirely. The single arm 44 is formed of resiliently flexible material that allows for the force to be transferred evenly about the second planar surface 272 of the flange 27. The arm 44 may be shaped so that is extends radially inwards at an oblique angle to the second planar surface 272.

It will be appreciated here that although the compressive collar has been described above as a protruding member that extends from the second planar surface of the flange portion, the compressive collar may be a separate element to the flange portion (and indeed the housing itself) which is only supported by the flange. Further, the compressive collar may have a toroidal structure, such as a torus, which is compressible under an applied force.

It will be understood that the invention is not limited to the embodiments above-described and various modifications and improvements can be made without departing from the concepts described herein. Except where mutually exclusive, any of the features may be employed separately or in combination with any other features and the disclosure extends to and includes all combinations and sub-combinations of one or more features described herein.

Claims

CLAIMS1. A coupling liquid housing for use with an ultrasonic transducer to inspect a surface of a component by local immersion ultrasonic testing, the coupling 5 liquid housing comprising: a sleeve (23) extending about a central longitudinal axis (26) and having a first longitudinal end (24) for receiving the ultrasonic transducer; and a flange (27) extending radially outwards from a second longitudinal end (25) of the sleeve (23); wherein the flange (27) has a first planar surface (271) which is suitable for being held in a sealed arrangement against the surface of the component, such that an interior of the sleeve (23) defines a reservoir for retaining an ultrasonic coupling liquid against the surface of the component.
2. The coupling liquid housing of claim 1, wherein the flange (27) is formed of a resiliently flexible material that is contourable to conform to the shape of the surface of the component to be inspected.
3. The coupling liquid housing of claim 1 or 2, wherein the flange (27) is in 20 the form of an annular ring.
4. The coupling liquid housing of claim 1, 2 or 3, further comprising a compressive collar (28) that surrounds the sleeve (23) and is in contact with a second planar surface (272) of the flange (27) on an opposite side of the flange 25 (27) to the first planar surface (271); wherein the compressive collar (28) is configured to engage the second planar surface (272) by resiliently deforming under a force applied by a user, so as to hold the first planar surface (271) in the sealed arrangement against the surface of the component.
5. The coupling liquid housing of claim 4, wherein: the compressive collar (28) comprises a protruding member (29) extending longitudinally from the second planar surface (272); and the protruding member (29) is in the shape of a curved surface of revolution (29) about the central longitudinal axis (26).
6. The coupling liquid housing of claim 5, wherein the protruding member 5 (29) has a plurality of slots (31) arranged in a uniform manner in an arc about the central longitudinal axis (26).
7. The coupling liquid housing of claim 4, wherein: the compressive collar (28) comprises an annular ring (41) extending in a 10 circumferential arc about the central longitudinal axis (26); the annular ring (41) is spaced from the flange (27) in the longitudinal direction by a plurality of resiliently flexible arms (42) that are arranged along an arc about the central longitudinal axis (26).
8. The coupling liquid housing of claim 4, wherein: the compressive collar (28) comprises an annular ring (41) extending in a circumferential arc about the central longitudinal axis (26); the annular ring (41) is spaced from the flange (27) in the longitudinal direction by a single, resiliently flexible arm (44) that extends along an arc about the central longitudinal axis (26) substantially entirely.
9 The coupling liquid housing of any one of claims 4 to 8, wherein: a rigid jacket (32) surrounds the sleeve (23) and is slideable along the sleeve (23) in the longitudinal direction; and the compressive collar (28) is configured to be compressed by movement of the rigid jacket (32) under an applied force.
10. A method of inspecting a surface (34) of a component by local immersion ultrasonic testing, the method comprising: placing the coupling liquid housing of any preceding claim onto a portion of the surface (34) of the component to be inspected; applying a force on the flange (27) in order to form a seal at the interface between the first planar surface (271) of the flange (27) and the surface (34) of the component, such that an interior of the sleeve (23) defines a reservoir for retaining an ultrasonic coupling liquid against the surface (34) of the component; inserting an ultrasonic transducer (35) into the sleeve (23) through the first end (24) of the sleeve (23); adding a coupling liquid into the sleeve (23) so as to immerse the ultrasonic transducer (35) in the coupling liquid; activating the ultrasonic transducer (35) so as to insonate the surface (34) of the component via the coupling liquid; and detecting ultrasonic wave energy following interaction with the surface 10 (34) of the component.