Acoustic port assembly

Abstract

The present application describes an acoustic port assembly (100) for an enclosure housing electrical equipment, comprising a frame (102) defining an aperture and mountable to a wall (106) of the enclosure, and an acoustically transparent barrier member (108) located across the aperture and between the frame and the wall in use, wherein the barrier member comprises a substantially rigid mesh having a porous structure defining a plurality of non-linear passageways through a thickness of the mesh. An enclosure or part thereof including the acoustic port assembly is also described.

Description

[0001] ACOUSTIC PORT ASSEMBLY

[0002] This present invention relates to an acoustic port assembly and in particular, but not exclusively, to an inspection window for monitoring or inspecting electrical equipment using an acoustic inspection device such as an acoustic imaging camera.

[0003] It is known to regularly monitor or inspect engineering equipment, particularly including electrical components, to maintain its performance and to identify and diagnose potential problems at an early stage. To carry out such monitoring and inspection, the equipment is typically shut down and then an enclosure housing the equipment is accessed by authorised personnel who would restart the equipment and carry out the required analysis of the equipment. A problem associated with this process is the likelihood of leading to prolonged periods of downtime, as well as health and safety risks on the personnel involved. It is known to use infrared (IR) cameras to monitor / inspect electrical equipment to prevent prolonged periods of downtime and health and safety risks, wherein a window is mounted in the housing surrounding the equipment to allow an IR camera or the like to remotely ‘see’ the equipment through the window. Such windows must be provided with panes, or lenses, that are manufactured from materials which permit the transmission of electromagnetic radiation in the IR wavelength range and in turn allow the contents within the equipment to be viewed through the window by the IR camera and inspected / monitored by qualified personnel. However, IR thermography detects heat, normally caused by a high resistance joint, and other causes of failure can occur.

[0004] It is known to use acoustic inspection devices to detect and pre-empt the failure of high, medium and low voltage electrical equipment. Typically, acoustic inspection devices help detect ‘partial discharge’ which is indicative of corona, tracking and arcing as a prelude to catastrophic electrical equipment failure due to dielectric / insulation failure. The typical operating range of acoustic inspection devices is around 2-130kHz.

[0005] Both infrared and acoustic inspection devices ideally require a ‘line of sight’ to the target in order to pinpoint an actual failure point. In certain circumstances, anacoustic inspection device can ‘hear’ a problem through a relatively small hole but cannot identify where, and exactly what, component in a particular piece of equipment is about to fail.

[0006] Traditional solutions for enabling acoustic inspections of electrical equipment have focused on an open hole or port which is installed into a panel and allows sound waves to pass through the opening to the acoustic inspection device. However, the resistance of a panel or enclosure against the intrusion of solids is strictly governed by ‘ingress protection’ (IP) ratings of IPOX to IP6X which vary in terms of the level of protection the panel or enclosure provides against access to hazardous parts, e.g. electrical conductors, etc, and the ingress of solid foreign objects. For example, a rating of IP1X has to protect any large surface of the body, such as the back of a hand, and prevent a sphere of >50mm fully penetrating the panel or enclosure, whereas a rating of IP5X has to be dust protected, not dust-tight, to prevent a substantial amount of dust entering the enclosure to interfere the safe operation of the equipment inside. Open holes or ports can also allow moisture to enter the live electrical equipment which could cause corrosion, electrical failure or even an explosion.

[0007] It is an aim of certain embodiments of the present invention to provide an acoustic port assembly for a housing containing electrical equipment subject to inspection, wherein the port assembly allows sound waves to pass through it whilst providing a barrier between an authorised inspector and the electrical equipment to meet the required IP rating.

[0008] It is an aim of certain embodiments of the present invention to provide an acoustic port assembly for a housing containing electrical equipment subject to inspection, including a high density mesh configured to allow sound waves to pass therethrough whilst protecting an authorised inspector located outside the housing and also allowing for a relatively large inspection port to be provided in the housing to allow the acoustic inspection device to identify where and what component in a particular piece of equipment is about to fail.According to a first aspect of the present invention there is provided an acoustic port assembly for an enclosure housing electrical equipment, comprising:

[0009] a frame defining an aperture and mountable to a wall of the enclosure; and an acoustically transparent barrier member located across the aperture and between the frame and the wall in use, wherein the barrier member comprises a substantially rigid mesh having a porous structure defining a plurality of non-linear passageways through a thickness of the mesh.

[0010] Optionally, a porosity of the mesh is 10-70%.

[0011] Optionally, the porosity is 49-54%.

[0012] Optionally, the thickness is at least 0.5mm.

[0013] Optionally, the mesh is configured to allow sound waves having a frequency of 2-130kHz to pass therethrough whilst preventing objects having a width of at least 1mm passing therethrough.

[0014] Optionally, the frequency is around 20-30kHz.

[0015] Optionally, the frame comprises a substantially S-shaped cross section defining a first flange region, a web region and a second flange region, wherein the first flange region engages an outer surface of the wall or an outer surface of an optional first gasket located between the frame and the wall, and wherein the second flange region engages an outer surface of the barrier member or an outer surface of an optional second gasket located between the frame and the barrier member, to thereby secure the barrier member between the frame and the wall.

[0016] Optionally, the web region defines an inner dimension corresponding to an outer dimension of the barrier member to laterally retain the barrier member in the frame.

[0017] Optionally, the assembly comprises a first gasket locatable between the frame and the wall, and a second gasket locatable between the frame and the barrier member.Optionally, the barrier member comprises a circular disc having a diameter of around 12.5-150mm and a thickness of around 1 -5mm.

[0018] Optionally, the mesh is a sintered mesh.

[0019] Optionally, the assembly comprises at least one window or lens for visually and / or thermally inspecting electrical equipment located inside the housing.

[0020] Optionally, the at least one window or lens is embedded in the mesh.

[0021] Optionally, the assembly comprises a cover member removably mountable to the frame and over the aperture.

[0022] According to a second aspect of the present invention there is provided an enclosure or part thereof comprising an acoustic port assembly according to the first aspect of the present invention.

[0023] Optionally, the part comprises an inspection panel of an enclosure for housing electrical equipment.

[0024] Optionally, the enclosure comprises a case for protecting an electronic device including a microphone and / or speaker.

[0025] Optionally the electronic device is a camera, mobile phone or tablet.

[0026] According to a third aspect of the present invention there is provided use of an acoustic port assembly according to the first aspect of the present invention to acoustically monitor or inspect electrical equipment located inside an enclosure to which the assembly is mounted.

[0027] According to a fourth aspect of the present invention there is provided use of an acoustic port assembly according to the first aspect of the present invention to allow sound waves to enter or exit a case to which the assembly is mounted and in whichan electronic device including a microphone, speaker and / or ultrasonic device is located.

[0028] Description of the Drawings

[0029] Certain embodiments of the present invention will now be described with reference to the accompanying drawings in which:

[0030] Figure 1 illustrates a cross section through an acoustic port assembly according to certain embodiments of the present invention.

[0031] Detailed Description

[0032] As illustrated in Figure 1 , an acoustic port assembly 100 according to certain embodiments of the present invention includes a frame 102 defining an aperture 104 and mountable in or on a wall 106 of a housing or panel. The wall 106 defines an inner surface 105 and an outer surface 107 with respect to electrical equipment locatable inside the housing and an authorised inspector / user locatable on the outside of the housing. The frame 102 is located on the outside of the wall and an acoustically transparent barrier member 108 is located across the aperture 104 and between the frame and the wall. A first gasket or seal 110, such as an O-ring, is aptly provided between the frame and the wall to seal that interface. A second gasket or seal 112, such as an O-ring, is aptly provided between the frame and the barrier member to seal that interface. The frame, aperture and / or barrier member may be any suitable shape, such as square or circular. For example, the frame may be substantially square and define a substantially square aperture which a substantially square barrier member extends across. Alternatively, the frame may be substantially square but defines a substantially circular aperture for a substantially square or circular barrier member to extend across. Further alternatively, the frame may be substantially circular and define a substantially circular aperture for a substantially circular barrier member to extend across. The frame and barrier member may be substantially planar or may be curved to mount on a correspondingly curved wall of, for example, a tubular or cylindrical housing, e.g. the duct of a high voltage isolated phase bus.Aptly, the frame 102 has a substantially S-shaped cross section which defines a first flange region 114, a web region 116 and a second flange region 118, wherein the first flange region 114 engages the outer surface 107 of the wall 106 or an outer surface of the optional first gasket 110, and wherein the second flange region 118 engages an outer surface of the barrier member 108 or an outer surface of the optional second gasket 112 to thereby securely sandwich / clamp the barrier member between the frame and the wall. Aptly, the web region 116 defines an inner dimension, such as an inner diameter if the frame is substantially circular, which corresponds to an outer dimension of the barrier member 108 to thereby laterally retain the barrier member in the frame. Aptly, the joint length defined by the web region 116 and the second flange region 118 is at least 3mm if adhesive is disposed between the frame and the barrier member, or at least 6mm if no adhesive is present, to thereby satisfy safety standards for blast-resistant / flameproof enclosures. Aptly, the inner surface length of the web region and the second flange region are substantially equal, i.e. at least 1 ,5mm each (with adhesive) or at least 3mm each (no adhesive). The frame may be configured to engage in the aperture of the housing wall. Aptly, the frame is substantially annular, and also the optional gaskets, and the mesh barrier member is a substantially circular disc.

[0033] The barrier member 108 is acoustically transparent meaning it is configured to allow sound waves to pass therethrough whilst acting as a barrier to objects, moisture, flames, sparks, etc. The barrier member 108 comprises a substantially rigid mesh having a thickness and a porous structure defining a plurality of non-linear passageways through the mesh from one side to an opposed second side. The porosity, i.e. the percentage of open space within the mesh structure, is around 10-70%, and aptly around 49-54%, for allowing sound waves having a frequency of around 2-130kHz, and preferably around 20-30kHz, to pass in either direction through the mesh. Aptly, the barrier member 108 is a circular disc having a diameter of around 12.5-150mm and preferably around 25mm. Alternatively, the barrier member may be substantially square having length and width dimensions of around 150x150mm. Aptly, the barrier member has a thickness of at least 0.5mm and aptly around 1-5mm. Aptly, the mesh is formed from stainless steel but may be another suitable metal such as brass, or it may be formed from a polymer material, or acomposite of metal and polymer such as polymer-coated metal. Preferably, the mesh is a sintered mesh. Sintered mesh is a high-strength, multi-layered material created by stacking layers of woven wire mesh, typically stainless steel, and bonding them together through a thermal diffusion process. Unlike a standard wire mesh lattice formed from multiple woven wires to define a single layer of uniformly distributed holes between the wires, the sintering process welds each intersection of the wires together, creating a rigid, uniform, and stable structure including complex, non-linear, three-dimensional passageways through the multiple layers of pores for fluids and gases to pass through a thickness of the mesh from one side to the other. The sintered structure forces a fluid to take a winding, non-linear, or tortuous path through the multiple layers of the mesh, which acts to quench a flame and / or blast waves in the event of an explosion inside the enclosure, whilst also preventing debris, such as dust, entering the enclosure during normal operation.

[0034] Aptly, the acoustic port assembly 100 may include one or more additional ports or windows to allow different forms of inspection device to ‘see’ or ‘hear’ a problem from outside the wall housing the equipment to be monitored or inspected. For example, the barrier member 108 may include a visually transparent window or lens to allow a person to visually inspect the equipment located on the other side of the wall.

[0035] Alternatively, or additionally, the barrier member 108 may include an infrared transmissive window or lens to allow an infrared thermal camera to ‘see’ the equipment located on the other side of the wall. The same window or lens may be visually and thermally transparent. Aptly, the additional window / s are embedded in the mesh. Alternatively, the additional window / s may be provided in the frame of the assembly and communicate with an additional aperture / s provided in the wall itself. Aptly, the assembly also includes a cover member removably mountable to the frame and over the aperture to close the same when the assembly is not in use to provide additional protection from within and outside the enclosure. The cover member may be screwed, bolted or hinged, or the like, to the frame.

[0036] Certain embodiments of the present invention therefore provide an acoustic port assembly for a housing containing electrical equipment subject to inspection, wherein the port assembly allows sound waves to pass through it whilst providing a barrier between an authorised inspector and the electrical equipment. The pluralityof non-linear passageways defined across a thickness of the mesh by for example non-aligned openings in adjacent layers of the mesh allow sounds waves to travel through the mesh from one side to the opposed other side whilst preventing, or at least damping / quenching, blast waves and / or flames from an explosive event from within or outside the enclosure passing through the mesh. The non-linear passageways prevent objects passing through the mesh and the porosity of the mesh can be predetermined to meet the desired IP rating and / or frequency range of acoustic inspection. The assembly may be mounted in a wall or an inspection panel of the housing. Alternatively, the assembly may be mounted in a case for an electronic device, such as a camera, mobile phone or tablet, to allow sound waves from an external source, such as a user, to enter the case and reach the device, such as to a microphone thereof, and / or to exit the case from the device, such as from a speaker thereof, and reach an external target, such as a user. In this embodiment, the barrier member is aptly configured to allow sounds waves having a frequency of less than 20kHz through the mesh, i.e. sound waves audible to a human, whilst preventing ignitable vapours or fluids from entering the case and coming into contact with the electronic device therein and also isolating an explosion or ignition inside the case to prevent any contact with ignitable substances outside the case. The barrier member of the case may be configured to allow ultrasonic sound waves through, such as the majority of the mesh being so configured and including a second port embedded therein for allowing light and / or sound waves of different frequencies therethrough, e.g. to / from a camera, speaker or microphone, or vice versa. The acoustic port assembly according to certain embodiments of the present invention desirably allows an imminent failure of electrical equipment to be determined early and efficiently and thereby prevents the equipment operating for long periods of time in an energy inefficient and environmentally unfriendly manner.

Claims

Claims1 . An acoustic port assembly for an enclosure housing electrical equipment, comprising:a frame defining an aperture and mountable to a wall of the enclosure; andan acoustically transparent barrier member located across the aperture and between the frame and the wall in use, wherein the barrier member comprises a substantially rigid mesh having a porous structure defining a plurality of non-linear passageways through a thickness of the mesh.

2. The assembly according to claim 1 , wherein a porosity of the mesh is 10-70%.

3. The assembly according to claim 2, wherein the porosity is 49-54%.

4. The assembly according to any preceding claim, wherein the thickness is at least 0.5mm.

5. The assembly according to any preceding claim, wherein the mesh is configured to allow sound waves having a frequency of 2-130kHz to pass therethrough whilst preventing objects having a width of at least 1mm passing therethrough.

6. The assembly according to claim 5, wherein the frequency is around 20-30kHz.

7. The assembly according to any preceding claim, wherein the frame comprises a substantially S-shaped cross section defining a first flange region, a web region and a second flange region, wherein the first flange region engages an outer surface of the wall or an outer surface of an optional first gasket located between the frame and the wall, and wherein the second flange region engages an outer surface of the barrier member or an outer surface of an optional second gasket located between the frame and the barrier member, to thereby secure the barrier member between the frame and the wall.

8. The assembly according to claim 7, wherein the web region defines an inner dimension corresponding to an outer dimension of the barrier member to laterally retain the barrier member in the frame.

9. The assembly according to any preceding claim, comprising a first gasket locatable between the frame and the wall, and a second gasket locatable between the frame and the barrier member.

10. The assembly according to any preceding claim, wherein the barrier member comprises a circular disc having a diameter of around 12.5-150mm and a thickness of around 1-5mm.

11. The assembly according to any preceding claim, wherein the mesh is a sintered mesh.

12. The assembly according to any preceding claim, comprising at least one window or lens for visually and / or thermally inspecting electrical equipment located inside the housing.

13. The assembly according to claim 12, wherein the at least one window or lens is embedded in the mesh.

14. The assembly according to any preceding claim, comprising a cover member removably mountable to the frame and over the aperture.

15. An enclosure or part thereof comprising an acoustic port assembly according to any preceding claim.

16. The part according to claim 15, comprising an inspection panel of an enclosure for housing electrical equipment.

17. The enclosure according to claim 15, comprising a case for protecting an electronic device including a microphone and / or speaker.

18. The case according to claim 17, wherein the electronic device is a camera, mobile phone or tablet.

19. Use of an acoustic port assembly according to any of claims 1 to 14 to acoustically monitor or inspect electrical equipment located inside an enclosure to which the assembly is mounted.

20. Use of an acoustic port assembly according to any of claims 1 to 14 to allow sound waves to enter or exit a case to which the assembly is mounted and in which an electronic device including a microphone, speaker and / or ultrasonic device is located.

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