DE202012005620U1 - Leakage detection device and an aircraft with a bleed air system and at least one leakage detection device - Google Patents

Abstract

Leak detection device (2), comprising a cuff (6) made of an elastic material for circumferentially wrapping a region of a fluid-carrying line (4), the cuff (6) having an inner surface and an outer surface (8) through which at least one recess extends (10), wherein at least one holder (16, 41) can be attached to the outer surface (8) at the edge of the recess (10), the at least one guide element (18, 20) for guiding a measuring element (22, 24) over the recess (10).

Description

TECHNICAL AREA

The invention relates to a leak detection device for a fluid-carrying line and a bleed air system for an aircraft with at least one bleed air line and at least one leakage detection device arranged thereon.

BACKGROUND OF THE INVENTION

In the prior art there are leakage detection devices that enable the detection of a leakage at a fluid line, when in the fluid line a heated compared to the environment of the fluid line fluid is guided. By enclosing a leakage-prone area and forming a defined outlet opening, a resulting leakage volume flow can be directed to a warning wire whose electrical properties are monitored. If significant changes occur in the electrical properties, leakage can be inferred.

It is known to provide bleed air ducts of aircraft with warning wires for the detection of leaks. Typically, these warning wires are in the form of a coaxial cable with center conductor and shell with thermally sensitive, eutectic salt as insulation. If there is a high level of heating due to leakage at a point along the warning wire, the eutectic salt resistance within that heated portion will decrease causing an applied voltage between the outer sheath and the center conductor to create a current flow through a control unit is measured. Such a device is approximately in DE 10 360 485 shown.

Further shows US 7,155,961 B2 a leakage detection device in which a sleeve made of a flexible material is placed around a part of a bleed air line of an aircraft, the sleeve has an opening for the passage of a leakage air mass flow and at the opening outside of the bleed air line warning wires are arranged, make the leakage of hot bleed air detectable ,

SUMMARY OF THE INVENTION

The guiding of warning wires to the outlet openings of sleeves has an optimization potential with regard to the vibrations or inertial forces occurring in a commercial aircraft.

The object of the invention is therefore to propose a leakage detection device, with the most accurate and reliable leakage detection on a bleed air line or another line leading a heated fluid can be realized, so that the probability of triggering a false alarm is particularly low.

The object is achieved by a leakage detection device having the features of independent claim 1. Advantageous embodiments and further developments can be taken from the subclaims and the following description.

The leakage detection device has a sleeve of an elastic material for circumferentially wrapping a portion of a conduit, wherein the sleeve has an inner surface and an outer surface through which extends at least one recess, wherein on the outer surface edge of the recess at least one holder is arranged, the Has at least one guide device for guiding a measuring member via the recess.

For the purposes of the invention, a conduit is to be understood as an arrangement of fluid guiding devices, which may comprise straight, curved and flexible conduits, as well as hoses, sleeves, flanges, couplings and other devices. The invention is therefore not limited to the arrangement of a leak detection device on only one of these devices.

The cuff of the leak detection device is therefore flexible and can be brought by winding on a line to be monitored. In order to allow subsequent attachment to a fluid-carrying line, the sleeve is preferably detachable and could have a Velcro fastener in an overlap region for attachment to the conduit, alternatively, bonding is contemplated, further alternatively attaching adhesive tapes over cuff edges and the fluid Piping or attaching Velcro straps to the edges of the cuff. The sleeve preferably has a bulky, air-enclosing and exemplary embodied as glass wool insulating material, which is preferably surrounded by a watertight sheath. Depending on the application, such as for monitoring bleed air lines, the cuff is temperature resistant up to about 200 ° C, is flame retardant and in particular has self-extinguishing properties.

Winding involves applying the cuff to the conduit so that the cuff circumferentially overlaps at its ends to form a closed perimeter. The cuff should therefore be dimensioned so that they are in a spatial direction a greater extent than that Has scope of the relevant line. Leakage occurring below this cuff causes the escaping air to spread between the air duct and the cuff and thus to flow outward from the next available port, this cuffed port being the cuffed bore in the cuff.

By arranged on the outside of the sleeve at least one holder at least one measuring element can be performed directly in a predetermined radial distance over the recess, so that an exiting warm fluid from the line meets directly on the at least one measuring device. A measuring element is preferably a warning wire, which is surrounded in the manner of a coaxial cable by a eutectic salt and a metallic sheath, as explained above.

The arrangement of the holder on the outer surface of the sleeve has the particular advantages that the at least one measuring element is reliably arranged at a predetermined distance above the recess, so that even with occurring vibrations or inertial forces, especially when used in an aircraft, nevertheless a safe Monitoring the line to a leakage is enabled.

In a particularly preferred embodiment, the holder is fastened exclusively to the sleeve. The avoidance of any contact of the holder with a surface of the fluid to be monitored leading line causes the recess in the cuff inevitably always lies below the measuring element. There is no need to supplement the sleeve with an opening for passing a holder. The measuring element is always guided over the recess at a defined distance. The mounting of a collar with a directly attached thereto holder is also much easier than the application of a cuff to a fluid-carrying line to which holders are already attached. The reliability of the monitoring is also significantly increased.

In an advantageous embodiment, the at least one holder is glued on the outside of the sleeve. Bonding creates a secure, cohesive bond that tolerates vibration and inertial forces. The adhesive used should be temperature-resistant, preferably up to about 200 ° C, when the leak detection device is to be used on a bleed air line of an aircraft. A temperature-resistant adhesive for temperatures up to about 135 ° C could be based on a two-component epoxy. For temperatures up to about 200 ° C, however, silicone-based adhesives would be better suited.

In an advantageous embodiment, the holder is arranged on a fastening band, which extends in at least one dimension over the outer contours of the holder and is sewn to the outer surface of the sleeve. The arrangement of a band, which is made of a cloth or other flexible, pliable material, allows a much smaller restriction of freedom of movement of the outer surface of the sleeve in a region below the holder, since about only the outer contour of the holder extending portions of the fastening band must be sewn and the space between the holder and the outer surface no connecting means such as adhesive or a seam comprises.

Preferably, the holder has a lower part and a holding part, which are fastened together enclosing the fastening tape. The holding part is a part of the holder, which takes over the technical function of holding or guiding the Messorgangs. The lower part is a part of the holder, which rests on the cuff. The fastening band between the two holder parts contributes to a sandwich-like construction.

In an advantageous embodiment, the fastening band is made of the same material as the outside of the sleeve. The cuff could include a plastic film, a plastic fabric, a fabric, an impregnated fabric, or other materials capable of tolerating a corresponding temperature range. Due to the identical material properties, the fastening tape can be very easily sewn or glued to the cuff.

In an advantageous embodiment, the holder is detachably arranged on the sleeve. This can be realized, for example, by a hook-and-loop fastener, in particular with a loop band and a hook band, for fastening the holder to the cuff, wherein the loop band is preferably arranged on the holder. The hook tape could be placed on the sleeve by an adhesive or stitched connection. The loop band can be understood in the sense of the preceding description as a fastening strap, which could be attached to the holder as the other straps. In addition to the simple attachment of a hook and loop fastener is advantageous that a loop or hook tape may have a higher strength than the wrapping material of the sleeve. There are alternative Velcro closures are known in which similar bands can be associated with each other, which are of course also used for releasably securing the holder. In addition, all known snap, click, button and latch connections can be used, in particular those which are known from the application to textiles.

In a particularly preferred embodiment, the hook and loop fastener extends over at least 50% of the circumference of the sleeve. This can be a particularly secure mechanical connection between the holder and the cuff caused, yet easy to manufacture.

In a further advantageous embodiment, the fastening tape is designed to be self-adhesive. This makes it possible to achieve particularly easy retrofitting, if cuffs are not to be removed from the line to be monitored.

In general, furthermore, the holder can be detachably arranged on the sleeve, which allows a subsequent attachment or readjustment of the position of the holder.

In an advantageous embodiment, the holder is formed from a metallic material and has at least one attachment surface, wherein the at least one guide element extends from one of the at least one attachment surface opposite side of the holder to the outside. The at least one mounting surface of the holder defining its underside serves to attach the holder to the outer surface of the sleeve. The guide element is further dimensioned such that the relevant measuring element is guided at a safe distance from the mounting surface

In an advantageous embodiment, the at least one guide element is adapted to support the measuring element. The guiding principle is only to be understood as a specification of a position and an extension direction. The holder can furthermore prevent the relevant measuring element from slipping out of the measuring element or being moved therein. The holder can be made by a positive or non-positive connection. In particular, a clamping connection is recommended, but here it is important to ensure that the clamping force is not squeezed when using a coaxial arrangement of wire, eutectic salt and metallic sheath so that there already arises a contact between the wire and the sheath ,

In an advantageous embodiment, the fastening strip extends to at least two sides over the outer contours of the holder. In this way, the holder can be arranged very securely on the outer surface of the sleeve by sewing a fastening band on both sides and allows a precise, reliable and constant alignment of a measuring element over the recess.

In an advantageous embodiment, the at least one guide element is groove-shaped, wherein the groove shape predetermines a direction of extension of a measuring element. The reliable alignment of the measuring element is thus further improved.

In an advantageous embodiment, the fastening strip extends to two sides over the outer contours of the holder, wherein the extension direction of the fastening strip is orthogonal to the extension direction of the groove-shaped guide element. The sewing of the fastening tape can therefore take place laterally from the guided measuring element, so that the lateral guidance of the measuring element is ensured even with strong vibrations over the recess.

In an advantageous embodiment of the invention, the holder has a width b, wherein the width of the fastening band exceeds the width b by at least 50%. The resulting, extending over the outer contours of the holder mounting tabs thus sufficient for secure attachment of the holder on the outer surface of the sleeve.

In a preferred embodiment, the sleeve is made thermally insulating, wherein between the inner surface and the outer surface of the sleeve, an insulating material is arranged. This can be, for example, a glass wool or another material enclosing air, which considerably limits the heat conduction or the heat transfer.

In an equally preferred embodiment, the holder is fixed by means of a positive connection to the fastening tape. The positive connection may be about a rivet connection or a sewn connection.

In an equally advantageous embodiment, the guide element on a longitudinally slotted socket made of an elastic material. This is also subsequently aufzustecken or clamp on a warning wire or the like.

Preferably, the holder has a receiving surface for receiving the bushing and a holding-down device, wherein the holding-down device can be fastened to the holder such that the bushing is clamped between the receiving surface and the holding-down device.

In a further advantageous embodiment, the holder has a metallic sheet, which allows a reliable and durable connection with a measuring device.

In a likewise advantageous embodiment, the holder has a pliable textile material, wherein the textile material may comprise a natural or synthetic fiber. The manufacture of the holder can thus be further simplified and the weight of the holder is relatively low, which makes it particularly suitable for use in an aircraft.

In a preferred embodiment, the holder on two guide elements, which allow the guiding of two parallel measuring organs on the recess of the sleeve, so that the reliability of the leakage detection is sufficiently large even if one of the measuring organs.

The invention further relates to a bleed air system for an aircraft with at least one bleed air line and at least one leakage detection device arranged thereon and described above. The bleed air line can comprise rectilinear or curved sections. It is particularly advantageous to arrange a leakage detection device on curved and flexibly designed line sections, which have a certain freedom of movement, for example in the manner of a bellows, although there the risk of possible leakage could be greater than at straight line sections.

BRIEF DESCRIPTION OF THE DRAWINGS

Other features, advantages and applications of the present invention will become apparent from the following description of the embodiments and the figures. All described and / or illustrated features alone and in any combination form the subject matter of the invention, regardless of their composition in the individual claims or their back references. In the figures, the same reference numerals for identical or similar objects.

1a and 1b show a leakage detection device according to the invention in and a detail view of a holder in plan views.

2 shows an aircraft with a bleed air system and a leakage detection device arranged thereon.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

1a shows a leakage detection device according to the invention 2 connected to a fluid-carrying pipe 4 is arranged. The leak detection device 2 has a cuff 6 on, the peripherally over the line 4 is wound and forms a closed perimeter. The cuff 6 here has an outer surface 8th and an inner surface, not visible in this illustration, which is integral with the outer surface of the conduit 4 communicates. In the cuff 6 there is also a recess 10 extending from the inner surface to the outer surface 8th extends. A leak below the cuff 6 on the line 4 Occurrence causes leakage of air, which consequently occurs between the pipe 4 and the inner surface of the cuff 6 spreads out, leaving them out of the recess 10 exit. This flow guide is particularly reliable given when the axially extending boundary edges 12 and 14 a flush contact with the line 4 However, this is not absolutely necessary and to allow thermal expansion of the line 4 possibly should be waived.

On the outside surface 8th there is a holder 16 , with the help of two guide elements 18 and 20 two warning wires 22 and 24 leads. The warning wires 22 and 24 may be made of a coaxial arrangement of a wire surrounded by a eutectic salt and a metallic cladding. A heat effect on the warning wire at a selected composition of the eutectic salt leads to a drastic reduction of the local electrical resistance, which is then detectable as a short circuit between the wire and the sheath. The prerequisite for this is the presence of a heated fluid from the recess 10 on the warning wires 22 respectively. 24 meets.

The peculiarity of the leakage detection device according to the invention 2 lies in the fact that the holder 16 directly on the outer surface 8th the cuff 6 is arranged and this the warning wires 22 and 24 directly at the edge of the recess 10 at a predetermined distance from the recess 10 leads. This can prevent the warning wires 22 and 24 above the cuff 6 by vibrations from the recess 10 be moved away or directly the cuff 6 touch, which could lead to a false alarm.

In addition to this, outside the cuff 6 another holder 26 be arranged, which is subject to the same design principles as the holder 16 , as described below by means of 1b is explained.

The holder 16 in 1b consists of an example of a metallic material, which is exemplified in the form of a sheet with several folds. Two tab-shaped attachment surfaces 28 and 30 extend laterally of the holder 16 to the outside and each have holes 32 on, for example, a riveted joint to a fastening tape 34 allow. The fastening tape 34 may comprise a limp textile material, wherein the fastening tape 34 clearly laterally over the fastening straps 28 and 30 extends beyond. The resulting tabs 36 and 38 can on the outside surface 8th the cuff with the help of sewing connections 35 sewn.

The holder further comprises two also exemplified as beveled plates guide elements 18 and 20 on, which are executed in several parts in the variant shown, so that a receiving surface 40 the putting on of a warning wire 22 or 24 allowed and an attachable hold-down 42 the clamping of the warning wire 22 respectively. 24 allowed. By way of example, a combination of a support surface 40 and a hold-down 42 in a fastened state form a circular holding cross-section, which coincides with the cross section of the warning wires 22 respectively. 24 corresponds. In the examples shown, the hold-down is 42 about a hinge 44 pivotally mounted, wherein the hold-down 42 via a screw connection 46 fixed relative to the support surface 40 is locked.

To further protect the leading warning wires 22 respectively. 24 can be between the bearing surface 40 and the hold-down 42 a one-sided slotted socket 48 be arranged from an elastic material, the subsequent postponement or clipping on a warning wire 22 respectively. 24 allowed and when fixing the hold-down 42 flush both the hold down 42 as well as the bearing surface 40 touched. By taking advantage of a residual elasticity of the socket 48 A sensitive warning wire can also be reliably supported by a force-locking connection.

As further in 1c can be represented, a holder 16 an upper holder part 39 and a lower part 37 have the fastening strap 34 by a riveted connection over the holes 32 lock in. This sandwich-like construction allows a particularly advantageous introduction of force into the fastening band 34 , as tensile forces also via a non-positive clamping connection between the holder part 39 and the lower part 37 in the fastening tape 34 be directed.

1d discloses the wrapping of a wire 4 with a cuff 6 in which there is an overlap area 7 forms, which causes the escaping fluid as safe as possible to the recess 10 the cuff 6 device.

1e discloses a variant in which a cuff 6 on a pipe 4 is arranged, the outside 8th the cuff 6 with a holder 41 equipped, the only one guide element 20 having. For fastening the holder 41 a Velcro connection is used, which consists of a loop band 43 and a hook tape 45 consists. The hook tape 45 can be on the outside 8th the cuff 6 glued or sewn on. The loop band 43 can be easily on the hook tape 45 Press to make a sufficiently secure connection.

2 shows an airplane 50 which engines 52 and an auxiliary power unit 58 which deliver bleed air from one or more compressor stages at a correspondingly high temperature. Bleed air lines 54 and 56 , which direct bleed air to bleed air consuming devices, may include straight sections and bent sections, the latter being capable of allowing thermal expansion and manufacturing tolerances in the manner of metal bellows. Due to the flexibility and the resulting possibility for changing the shape, leakages can also occur, in particular at these deflections, with the aid of leakage detection devices 2 can be detected according to the present invention. In principle, however, all sections of bleed air ducts 54 and 56 with such a leak detection device 2 monitored. In particular, the area of a hull 60 of the plane 50 , the auxiliary engine 58 should, with the help of a leak detection device 2 be monitored, because the leakage of bleed air in a pressurized area of the aircraft 50 should be prevented as completely as possible by appropriate design measures.

In addition, it should be noted that "having" does not exclude other elements or steps, and "a" or "an" does not exclude a plurality. It should also be appreciated that features described with reference to any of the above embodiments may also be used in combination with other features of other embodiments described above. Reference signs in the claims are not to be considered as limiting.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 10360485 [0003]
• US 7155961 B2 [0004]

Claims (15)

Leak detection device ( 2 ), comprising a cuff ( 6 ) made of an elastic material for circumferentially wrapping a portion of a fluid-carrying line ( 4 ), whereby the cuff ( 6 ) an inner surface and an outer surface ( 8th ), through which at least one recess ( 10 ), wherein on the outer surface ( 8th ) at the edge of the recess ( 10 ) at least one holder ( 16 . 41 ) is attachable, the at least one guide element ( 18 . 20 ) for guiding a measuring device ( 22 . 24 ) over the recess ( 10 ) having. Leak detection device ( 2 ) according to claim 1, wherein the at least one holder ( 16 . 41 ) exclusively on the cuff ( 6 ) is attached. Leak detection device ( 2 ) according to claim 1 or 2, wherein the at least one holder ( 16 . 41 ) on the outside ( 8th ) of the cuff ( 6 ) is glued. Leak detection device ( 2 ) according to one of the preceding claims, wherein the holder ( 16 . 41 ) on a fastening band ( 34 ) arranged in at least one dimension over the outer contours of the holder ( 16 . 41 ) and on the outer surface ( 8th ) of the cuff ( 6 ) is sewn. Leak detection device ( 2 ) according to claim 1, wherein the holder ( 16 . 41 ) detachable on the cuff ( 6 ) is attached. Leak detection device ( 2 ) according to one of the preceding claims, wherein the holder ( 16 . 41 ) comprises a metallic material and at least one attachment surface ( 28 . 30 ), wherein the at least one guide element ( 18 . 20 ) of one of the at least one attachment surface ( 28 . 30 ) opposite side of the holder ( 16 . 41 ) extends to the outside. Leak detection device ( 2 ) according to one of the preceding claims, wherein the cuff ( 6 ) detachable on a fluid-carrying line ( 4 ) is attachable. Leak detection device ( 2 ) according to one of the preceding claims, wherein the at least one guide element ( 18 . 20 ) is groove-shaped, wherein the groove shape a measuring element ( 22 . 24 ) specifies an extension direction. Leak detection device ( 2 ) according to claim 3, wherein the fastening band ( 34 ) to two sides over the outer contours of the holder ( 16 . 41 ) extends, wherein the extension direction of the fastening band ( 34 ) to the extending direction of the groove-shaped guide member (FIG. 18 . 20 ) is orthogonal. Leak detection device ( 2 ) according to one of the preceding claims, wherein the holder ( 16 . 41 ) a receiving surface ( 40 ) for receiving a longitudinally slotted socket ( 48 ) and a hold-down ( 42 ), wherein the hold-down ( 42 ) on the holder ( 16 . 41 ), that the bushing ( 48 ) between the receiving surface ( 40 ) and the hold-down ( 42 ) is trapped. Leak detection device ( 2 ) according to one of the preceding claims, wherein the holder ( 16 . 41 ) has a metallic sheet which provides a reliable and durable connection to a measuring device ( 18 . 20 ) allowed. Leak detection device ( 2 ) according to one of the preceding claims, wherein the holder ( 16 . 41 ) has a limp textile material. Leak detection device ( 2 ) according to one of the preceding claims, wherein the holder ( 16 . 41 ) two guide elements ( 18 . 20 ), the guiding of two parallel measuring organs ( 22 . 24 ) over the recess ( 10 ) of the cuff ( 6 ) allow. Plane ( 50 ) with a bleed air system, the at least one bleed air line and at least one leak detection device arranged thereon ( 2 ) according to any one of claims 1 to 13. Plane ( 50 ) according to claim 14, wherein at least one leak detection device ( 2 ) at one in a non-pressurized area of a fuselage ( 60 ) of the aircraft ( 50 ) is arranged.

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