GB2522079A

GB2522079A - Vent cover

Info

Publication number: GB2522079A
Application number: GB1402356.8A
Authority: GB
Inventors: Eddie Adams
Original assignee: Megger Instruments Ltd
Current assignee: Megger Instruments Ltd
Priority date: 2014-02-11
Filing date: 2014-02-11
Publication date: 2015-07-15
Anticipated expiration: 2034-02-11
Also published as: GB2522079B; GB201402356D0

Abstract

Apparatus are provided, including an electrical apparatus (100), an electrical apparatus case and a vent cover (112) for an electrical apparatus (100), which include measures for covering a ventilation opening (122) in an inclined mounting surface (110). The vent cover (112) comprises: a sealing surface (118) at least partially encircling the ventilation opening (122) and being sealed to the inclined mounting surface (110); an inclined central surface region (114), arranged substantially parallel to the inclined mounting surface (110); a ventilation surface region (120) extending between a lower edge region (118c) of the vent cover (112) and the inclined central surface region (114), the ventilation surface region (120) comprising one or more orifices (130) for permitting airflow through the vent cover (112), and an imperforate surface region (116) extending between the inclined central surface region (114) and the sealing surface (118), the imperforate surface region (116) being configured to encourage incident liquids away from the ventilation surface region (120).

Description

VENT COVER

Technical Field

The present invention relates to coverings for ventilation openings. In particular, but not exclusively, to coverings for ventilations in electrical equipment.

Background

Electrical equipment is known to dissipate energy in the form of heat during operation. For an electrical apparatus comprising an item of electrical equipment mounted in a case or other housing, it is often necessary to expel that heat from the case to maintain the operating temperature of the electrical equipment within a desired operating range. A conventional cooling method is to expel warm air from the case and/or intake cool air into the case by means of one or more ventilation openings in the walls of the case. The circulation of air is often aided through the use of fans.

However, it is sometimes also necessary to prevent the ingress of liquids or particulate matter into the case, which could otherwise cause damage to the components of the electrical equipment, jeopardise stable operation of the electrical equipment, risk fire or explosion caused by short circuits, as well as increase the risk of electric shock to a user of the electrical equipment.

Certain known kinds of electrical apparatus protect the electrical equipment with a protective lid, which, when closed, covers any ventilation openings as well as, for example, any electrical input terminals, display screens and the like. Accordingly, the electrical equipment is rendered water (and particulate) resistant but typically non-operational when the lid is closed, while being vulnerable to incident water, such as rain or splashes, and ingress of conductive particulate matter, during operation when the lid is opened and the ventilation openings are exposed.

Further, it is known that ventilation openings in electrical apparatus provide one or more paths between a user and circuitry of the electrical equipment inside the case.

Such paths typically include a path length through air, referred to as a clearance path length, and/or a path length which extends along the surfaces of internal structures of the apparatus, referred to as a creepage path length. Contamination of internal surfaces due to moisture or particulate matter can reduce one or more of these path lengths.

Especially for high voltage or high energy electrical equipment, the ventilation openings can introduce a risk of electric shock to a user of the electrical equipment, if a path length is too short. This risk is exacerbated for portable electrical equipment, where a natural desire for smaller sized apparatus results in live electrical components being closer to the ventilation openings, in order to facilitate the more compact size of the apparatus.

Balancing all of these often competing demands and requirements provides a significant design challenge for producers of electrical apparatus.

Summary

According to a first aspect of the present invention, there is provided an electrical apparatus comprising: an electrical equipment; a case, comprising a body housing the electrical equipment; a closure, coupled to the body, for sealing the electrical equipment within the body, the closure having walls upstanding from the body, one of the walls being an inclined mounting surface comprising at least one ventilation opening for enabling airflow through the closure; and a convex vent cover covering the ventilation opening, the vent cover comprising: a sealing surface at least partially encircling the opening and sealed to the mounting surface, an inclined central surface region; a ventilation surface region extending between a lower edge region of the vent cover and the inclined central surface region, the ventilation surface region comprising one or more orifices for permitting airflow through the vent cover, and an imperforate surface region extending between the inclined central surface region and the sealing surface, the imperforate surface region being configured to encourage incident liquids away from the ventilation surface region.

According to a second aspect of the present invention, there is provided an electrical apparatus substantially in accordance with any of the examples as described herein with reference to and as illustrated by the accompanying drawings.

According to a third aspect of the present invention, there is provided a case for an electrical apparatus, the case comprising: abody; a closure, coupled to the body, the closure having walls upstanding from the body, one of the walls being an inclined mounting surface comprising at least one ventilation opening for enabling airflow through the closure; and a convex vent cover covering the ventilation opening, the vent cover comprising: a sealing surface at least partially encircling the opening and sealed to the mounting surface; an inclined central surface region; a ventilation surface region extending between a lower edge region of the vent cover and the inclined central surface region, the ventilation surface region comprising one or more orifices for pennitting airflow through the vent cover; and an imperforate surface region extending between the inclined central surface region and the sealing surface, the imperforate surface region being configured to encourage incident liquids away from the ventilation surface region.

According to a fourth aspect of the present invention, there is provided a case for an electrical apparatus substantially in accordance with any of the examples as described herein with reference to and as illustrated by the accompanying drawings.

According to a fifth aspect of the present invention, there is provided a convex vent cover for covering a ventilation opening on an inclined mounting surface of an electrical apparatus, the vent cover comprising: a sealing surface for at least partially encircling the opening, the sealing surface being sealable to the mounting surface; an inclined central surface region; a ventilation surface region extending between a lower edge region of the vent cover and the inclined central surface region, the ventilation surface region comprising one or more orifices for permitting airflow through the vent cover; and an imperforate surface region extending between the inclined central surface region and the sealing surface, the imperforate surface region being configured to encourage incident liquids away from the ventilation surface region.

According to a sixth aspect of the present invention, there is provided a vent cover substantially in accordance with any of the examples as described herein with reference to and as illustrated by Figure 3, optionally as modified by figures 5 and 6.

Brief Description of the Drawings

Figure 1 is a side view of an electrical apparatus according to embodiments; Figure 2 is a perspective view of an electrical apparatus according to embodiments; Figure 3 is a front perspective view of a vent cover according to embodiments; Figure 4 is a perspective view of an electrical apparatus according to embodiments; Figure 5 is a rear perspective view of a vent cover according to embodiments; Figure 6 is a rear perspective view of a vent cover according to embodiments, and Figure 7 is a rear perspective view of an electrical apparatus according to embodiments.

Detailed Description

Figure 1 illustrates a side view of an electrical apparatus 100, and Figure 2 shows a perspective view of the electrical apparatus 100, according to an embodiment.

Apparatus 100 includes a case, comprising body 102 and lid 104. Body 102 houses the electrical components of a respective item of electrical equipment. In some embodiments the electrical equipment may be an electrical test equipment, such as an ohmmeter, ammeter, voltmeter, or suchlike. In embodiments, the electrical equipment comprises one or more of a power supply, measurement circuitry, processing circuitry, memory, a display and an input/output (I/O) interface.

Lid 104 is coupled to body 102 by means of a rotatable coupling 106. In the embodiment depicted in Figure 1, rotatable coupling 106 comprises at least one hinge.

In Figure 1, lid 104 is shown in an open configuration. When in a closed configuration, edge region 1 04a of lid 104 is brought into contact with edge region 1 02a of body 102.

Edge regions 102a and 104a cooperate to provide a seal which serves to prevent the ingress of liquids and particulate matter when lid 104 is in the closed configuration.

One or more of edge regions 102a and 104a may comprise a liquid-resistant sealant material, such as nitrile, neoprene, silicon or rubber, to aid in preventing liquid ingress when lid 104 is in the closed configuration, Body 102 and lid 04 are electrically insulated from the electrical components within the body. Body 102 and lid 104 may be formed from an electrically insulating material, such as a plastics material.

Apparatus 100 also includes a closure 108, which covers and seals the electrical components of the electrical equipment within the body portion 102, and serves to protect the electrical equipment when the lid is in an open configuration. Closure 108 also serves to prevent a user from coming into contact with the electrical components when the lid is in an open configuration, Closure 108 may comprise an interaction surface I 08a upon which a display and/or one or more input tenninals, output terminals or user input means, such as buttons, switches and the like (not shown) may be provided. In some embodiments, interaction surface 108a is substantially horizontal.

In other embodiments (as illustrated), interaction surface 108a is inclined away from rotatable coupling 106 to provide an improved viewing angle to a user of the apparatus, Closure 108 may also comprise a flange 108b for securing the closure 108 to body portion 102, for example using fixing means such as one or more screws, clasps or clips, In embodiments, the flange 108b is substantially horizontal during normal use of the apparatus 100.

Closure 08 comprises a number of walls, upstanding from body 102, extending between flange 1 08b and interaction surface 1 08a, including inclined mounting surface 110. Inclined mounting surface 110 is located in an end region of closure 108 adjacent to rotatable coupling 106. In embodiments, inclined mounting surface 110 is a rear wall of closure 108, arranged to be on an opposite side of apparatus 100 than a user during normal operation of the apparatus. Inclined mounting surface 110 of the closure 108 includes one or more ventilation openings, or vents, for facilitating airflow between the inside of body 102, where the electrical components of the electrical equipment are situated, and the outside of the case. In embodiments, inclined mounting surface 110 is inclined towards rotatable coupling 106, that is, the internal angle of the inclined mounting surface with respect to the horizontal is an acute angle. In some embodiments, inclined mounting surface t tO is configured with an internal angle of between 45° and 75° to the horizontal. In some embodiments, inclined mounting surface 110 is configured with an internal angle of between 55° and 65° to the horizontal. In some embodiments, inclined mounting surface 110 is configured with an internal angle of at between 45° and 60° to the horizontal, In some embodiments, inclined mounting surface 110 is configured with an internal angle of substantially 60° to the horizontal. In the embodiments described above, the horizontal is referenced during normal operation of the apparatus 100 as being parallel to a surface on which the apparatus is positioned, In embodiments, plane of flange lO8b is substantially equal to the horizontal during normal operation of apparatus 100.

Apparatus 100 further includes one or more vent covers 112, configured to restrict the ingress of water and/or particulate matter via the ventilation openings in inclined mounting surface 110, In embodiments the one or more vent covers 2 are convex. In embodiments, the one or more vent covers 112 are substantially hollow.

Figure 3 shows a vent cover 112 in greater detail, according to an embodiment, separated from the remainder of apparatus 100.

As depicted in the embodiment in Figures and 2, vent cover 112 is mounted over a ventilation opening in inclined mounting surface 110. With reference also to Figure 3, it may be seen that, in general terms, the vent cover I U has an upper, closed region and a lower, ventilation region, as viewed when mounted on the inclined mounting surface 110 during normal operation of the apparatus 100. More particularly, according to the present embodiment, vent cover 112 comprises an inclined central surface region 114. Central surface region 114 is inclined towards rotatable coupling too. In some embodiments, inclined central surface region 114 is arranged to be substantially parallel to inclined mounting surface 110. In embodiments, inclined central surface region t t4 is configured at an angle of between 45° and 75° to the horizontal. In some embodiments, inclined central surface region N is configured at an angle of between 55° and 65° to the horizontal. In some embodiments, inclined central surface region 114 is configured at an angle of between 45° and 600 to the horizontal. In some embodiments, inclined central surface region 114 is configured at an angle of substantially 60° to the horizontal.

As shown, vent cover 112 additionally comprises a peripheral surface region 116 which extends between inclined central surface region 114 and a sealing surface 118 of vent cover 112. Sealing surface 118 is configured to abut or otherwise contact with inclined mounting surface 110 to provide a liquid resistant seal between vent cover 112 and inclined mounting surface 110. Hence, when vent cover 112 is coupled to inclined mounting surface 110, sealing surface 118 may be considered to be sealed to inclined mounting surface 110. In embodiments, the peripheral surface region 116 is an imperforate surface region, which acts to encourage incident liquid around and/or away from the ventilation opening in inclined mounting surface 110.

Vent cover 112 further comprises a ventilation surface region 120, which is configured to permit airflow through the vent cover. In the embodiment shown, ventilation surface region 120 extends substantially vertically, that is, at an angle of substantially 90° to the horizontal during normal use of apparatus 100. In further arrangements, ventilation surface region 120 may be negatively inclined, such that the top of ventilation surface region 120 overhangs the bottom of ventilation surface region 120, in other words with an obtuse internal angle to the horizontal during normal operation of apparatus 100. The effect of arranging ventilation surface region 120 substantially vertically, or with a negative incline, is to prevent any vertically falling liquid from landing on the ventilation surface region 120. Such vertically falling liquid would instead contact another part of vent cover 112 and be encouraged away from the ventilation surface, for example, due to the contouring of imperforate surface region 116, or would contact inclined mounting surface 110 and be encouraged around vent cover 112 by the contouring of sealing surface 118. In some embodiments, when in the open configuration, lid 104 is held in a substantially vertical position, as depicted in Figure 1. In such embodiments, lid 104 serves to prevent liquids which travel at an incident angle towards ventilation surface region (that is, travelling left to right in the context of Figure 1) from contacting ventilation surface region 120. Additionally, any liquid that comes into contact with the ventilation surface region 120 will tend to flow off due to the vertical or negative inclination of the surface.

The low profile of vent cover 112, applied to a closure having an inclined mounting surface 110, advantageously enables very efficient use to be made of the available space within the case of apparatus 100, with a relatively large proportion of the volume of the case being made available for electrical components. This allows a S given size of electrical equipment to fit within a relatively smaller case, whilst providing resistance to incident liquids and/or particulate matter during operation of the apparatus when the lid is open. Further, the relative angles and orientations of the various surface regions of vent cover 112 enable inclined mounting surface 110 to be provided at a relatively steep angle, thereby frirther increasing the volume available for electrical components within the volume defined between body 102 and closure 108. Since efficient use of space within the case is important, and due to the way in which the lid according to the present embodiment can be removed (as will be described hereinafter), it is preferable not to manufacture inclined mounting surface 110 of closure 108 to be vertical in orientation. Vent cover 112 also therefore enables a vertical ventilation surface region 120 to be employed in such scenarios. The configuration of the vent covers of embodiments are discussed in further detail below.

In Figure 2, apparatus 100 is shown with two ventilation openings in inclined mounting surface 110. One ventilation opening is covered by vent cover 112. The other ventilation opening 122 is depicted without the corresponding vent cover in order to illustrate the underlying features of inclined mounting surface 110.

In the embodiment depicted in Figure 2, ventilation opening 22 has a circular shape. In alternative embodiments (not shown), ventilation opening may be provided in a different shape, such as a square or other (regular or irregular) polygon. A fan may be provided behind ventilation opening 122 to increase airflow through inclined mounting surface 110 of closure 108. At least a portion of central surface region 114 may be arranged within a projection of ventilation opening U2 in a direction perpendicular to inclined mounting surface 110. Central surface region 114 may be arranged within a projection of ventilation opening 122 in a direction perpendicular to inclined mounting surface 110. At least a part of ventilation surface region 120 may be outside of a projection of ventilation opening 122 in a direction perpendicular to inclined mounting surface 110.

As illustrated in Figures 2 and 3, apparatus 100 further comprises mounting means 124, comprising at least mounting portions 124a and 124b, for attaching a vent cover to inclined mounting surface 110 over ventilation opening 122. Inclined mounting surface 110 comprises mounting portion 124a. As depicted in Figure 2, mounting portion 124a comprises a screw boss. Vent cover 112 comprises corresponding mounting portion 124b of mounting means 124, which in the embodiments depicted in Figure 2 comprises a through-hole 124b, for receiving mounting screw 124c. In alternative embodiments, mounting portions 124a and 124b may comprise one or more clasp portions, clip portions, latch portions etc. In embodiments, the inclined central surface region 114 comprises mounting portion 124b. In the embodiment depicted in Figure 2, apparatus 100 further comprises one or more braces 126, or spokes, for supporting mounting portion 124a in ventilation opening 122. Mounting 1 24a may be affanged axially in a circular ventilation opening 122.

According to the present embodiment inclined mounting surface 110 comprises a receiving portion 128, which substantially follows the footprint of sealing surface 118 of vent cover 112. Receiving portion 128 may comprise a groove or recess configured to receive sealing surface 118 of vent cover 112. Alternatively, receiving portion 128 may comprise a ridge, configured to fit within, or otherwise be received by, sealing surface 118 of vent cover 112. One or more of receiving portion 128 and sealing surface 118 of vent cover 112 may comprise an inlay, for example a seal comprising a material such as nitrile, neoprene, silicon, rubber etc., to aid in preventing liquid and/or particulate ingress when between receiving portion 128 and sealing surface 118 of vent cover 112.

In the embodiments, as most clearly depicted in Figure 3, impeiforate surface region 116, which extends between inclined central surface region 114 and at least a part of sealing surface 118, extends along a curved proffle. In alternative embodiments, imperforate surface region 116 may extend along a flat inclined profile. In the embodiment depicted in Figure 3, sealing surface 118 of vent cover 112 extends around a curved upper edge region 118a of sealing surface 118, and down adjacent side edge regions II 8b of sealing surface 118. In alternative embodiments, upper edge region 11 8a may comprise linear, inclined edges, for example in the shape of an inverted V' arrangement, Imperforate surface region 11 6 extends between inclined central surface region 114 and upper edge region 1 18a. In some embodiments, imperforate surface region 116 further extends between inclined central surface region 114 and side edge regions 118b. In embodiments, one or more of upper edge region 118a and the side edge regions Ii 8b are configured to provide a liquid and particulate resistant seal between the vent cover and the inclined mounting surface. In such a manner, sealing surface 118 can be considered to at least partially encircle ventilation opening 122.

Ventilation surface region 120 extends between inclined central surface region 114 and a lower edge region 11 8c of sealing surface 8. As shown, lower edge region 1 18c may be a linear edge region, which is horizontal. Ventilation surface region 120 comprises one or more orifices 130 to facilitate airflow through ventilation cover 112.

In the embodiment depicted in Figure 3, one or more orifices 130 comprise a plurality of vertically aligned slots, defined by a plurality of guard portions 132, which are configured to prevent objects with a diameter greater than a predetermined size from passing through ventilation surface region 120. In this manner, vent cover 112 is configured to ensure that such objects maintain at least a minimum predetermined distance from the ventilation openings 122 in inclined mounting surface 110, and therefore from the electrically conductive components located within body 102.

The one or more guard portions 132 may be configured to restrict access via ventilation surface region 120 for objects with a diameter greater than 5mm. This serves to restrict access via vent cover 112, for example, of an operator's fingers, and thereby acts to mitigate the risk of electric shock for a user of apparatus 100 which may result from proximity to the electrically conductive components located within body 102. In some embodiments, the one or more guard portions 132 are configured to restrict access via ventilation surface region 120 for objects with a diameter greater than 3mm. The relative positioning of the various surface regions of vent cover 112, as well as the relative displacement between ventilation opening 122 in the inclined mounting surface and the one or more orifices 130 in ventilation surface region 120 serves to increase the length of the air and/or surface path between the user and any electrically conductive components within the body 102. In this manner, use of vent cover 112 assists deployment of an apparatus in a small volume case, while protecting a user of the apparatus from potentially hazardous voltages, which could otherwise give rise to an ii electric shock. In embodiments, vent cover 112 is configured to provide predetermined minimum air and/or surface path lengths between the ventilation opening in inclined mounting surface 110 and ventilation surface region 120. In some embodiments, the predetermined minimum air and/or surface path lengths have a distance of at least 20mm. In a similar fashion to the body 102, vent cover 112 is electrically insulated from the electrical components of apparatus 100. In some embodiments, vent cover 112 comprises an electrically insulating material, such as a plastics material. In some embodiments, the width of the one or more orifices 130 in ventilation surface region is less than 5mm. In some such embodiments, the width of the one or more orifices 130 in ventilation surface region 120 is less than 3mm.

Ventilation surface region 120 extends to lower edge region I 18c of vent cover 112. As shown, ventilation surface region 120, and the orifices therein, may extend around a lip portion 134 configured at lower edge region 11 8c of vent cover 112.

Configuring ventilation surface region 120 such that it extends around lip portion 134 encourages any incident liquid that falls on ventilation surface region 120 to run out of the bottom of the one or more orifices 130, rather than through the orifices 130 and into vent cover 112. According to the present embodiment, the width of vent cover 112 increases from the upper edge region I 18a towards the lower edge region 120. This conveniently facilitates provision of a larger ventilation surface region 120, thereby improving airflow through the vent cover 112.

Figure 4 illustrates a perspective view of apparatus 100, with two vent covers in place. Where two or more ventilation openings 122, and corresponding vent covers 112, are provided on inclined mounting surface 110, at least one may be used as an inlet for airflow, and at least one may be used as an exhaust for airflow. In this manner the circulation of air through the apparatus, and therefore the cooling performance, may be further improved. In alternative embodiments, both ventilation openings 22 may be used as inlets for airflow, or both ventilation openings 122 may be used as exhausts for airflow.

Figure 5 shows a perspective view of the rear of vent cover 112 according to an embodiment. In the embodiment depicted in Figure 5, a filter portion 136 is arranged within vent cover 112 to improve the resistance of ventilation surface region 120 to the ingress of liquid and/or particulate matter, such as dust. As such, the embodiment depicted in Figure 5 may be considered as an addition to, or a modification of, one or more of the previously described embodiments. Filter portion 136 may have a relatively high permeability to gasses, but a relatively low permeability to liquids and/or particulate matter. In some embodiments, filter portion 136 comprises a gas permeable membrane. In some embodiments, filter portion 136 comprises a foam. In some embodiments, filter portion 136 comprises polyether polyurethane. In embodiments in which vent cover 112 comprises a filter portion 136, incident liquid falling on ventilation surface region 120, through orifices 130 between the one or more guard portions 132, will fall onto filter portion 136, run down the surface of the filter portion, and be encouraged out of the bottom of vent cover 112 through the orifices 130 which extend around lip portion 134. In the embodiment depicted in Figure 5, vent cover 112 further comprises a filter enclosure portion 138 for securing filter portion 136 in a position adjacent to ventilation surface region 20, Filter portion 36 may be configured to substantially cover the one or more orifices 130 in ventilation surface region 120. Filter enclosure portion 138 serves to urge filter portion 136 against the one or more orifices 130 in ventilation surface region 120, thereby providing a seal to prevent liquid and/or particulate matter from passing around filter portion 136 and through ventilation opening in inclined mounting surface 110.

Fiher enclosure portion 138 may be artached to vent cover 112 via one or more catch portions 140a on filter enclosure portion 138, and corresponding catch portions 14Db on the inner surface of vent cover 112. Filter enclosure portion 138 comprises one or more orifices 142 to facilitate airflow through filter enclosure portion 138. In embodiments, filter enclosure portion 138 further comprises one or more guard portions 144 for supporting filter portion 136 against ventilation surface 120 of vent cover 112.

Guard portions 144 further aid in restricting access via vent cover 112 for objects with a diameter greater than a predetermined size, In embodiments, the orifices 142 and/or the guard portions 144 are aligned with the corresponding orifices 130 and/or guard portions 132 of ventilation surface 120. In some embodiments, filter enclosure portion 138 is removable to facilitate replacement of filter portion 136. In Figure 5, vent cover 112, filter portion 136 and filter enclosure portion 138 are shown in an exploded configuration to allow the construction of these parts to be more readily understood. In I 3

Figure 6 shows a perspective view of the rear of vent cover 112 according to embodiments in an assembled configuration. Filter enclosure portion 138 is shown attached to vent cover 112, via catch portions 140a and 140b, in order to secure filter portion 136 in a position covering the inner surface of ventilation surface region 120.

In alternative embodiments, catch portions 140a and 140b may support filter portion 136, but not secure filter portion 136 in a position. In the embodiments depicted in Figure 6, vent cover 112 further comprises one or more protrusions 146a, configured to couple with filter enclosure portion 138 via one or more protrusion holes 146b, configured to align filter enclosure portion 138 in the correct position when attached to vent cover 112. In embodiments, the one or more protrusions 146a are swaged in order to secure filter enclosure portion 138 in place and thereby secure filter portion 136 in place against ventilation surface 120, In alternative embodiments, an alternative fixing means is provided for securing filter enclosure portion 138 in place, such as a catch, latch or separable friction fitting.

Figure 7 illustrates another side view of an apparatus 100 according to embodiments. In the embodiments depicted in Figure 7, the rotatable coupling 106 is arranged so that lid 04 can be removed from body 102. In order to remove lid 104 from body 102, lid 104 must be orientated at a predetermined, non-upright angle in relation to body 102, as shown in Figure 7. In this way, the lid 104 cannot be removed when it is either at rest in an open or a closed configuration, In embodiments, the removal configuration comprises lid 04 being arranged with an internal angle of between 45° and 75° to the horizontal. In some embodiments, the removal configuration comprises lid 104 being arranged with an internal angle of between 55° and 65° to the horizontal. In embodiments, the removal configuration comprises lid 104 being arranged with an internal angle of between 45° and 60° to the horizontal. In some embodiments, the removal configuration comprises lid 104 being arranged with an internal angle of substantially 60° to the horizontal. In the embodiments described above, the horizontal is referenced during normal operation of the apparatus 100. In embodiments, the plane of flange 108b is substantially equal to the horizontal during normal operation of apparatus 100.

In embodiments, the removal configuration comprises edge portion I 04a of lid 104 being arranged at an angle of between 45° and 75° to edge portion 102a of body 102. In embodiments, the removal configuration comprises edge portion 104a of lid 104 being arranged at an angle of between 55° and 65° to edge portion 102a of body 102. In embodiments, the removal configuration comprises edge portion 104a of lid 104 being arranged at an angle of between 45° and 60° to edge portion 1 02a of body 102. In embodiments, the removal configuration comprises edge portion 104a of lid 104 being arranged at an angle of substantially 60° to edge portion 102a of body 102.

When in the removal configuration, lid 104 may be decoupled from body 102 by displacing lid 104 relative to the body 102 along the axis of rotatable coupling 106, that is, in a direction into the page in the context of Figure 7. Accordingly, when at the appropriate angle for removal, the lid must pass over and clear the closure 108 and vent cover 112 in order that it call be displaced sideways and removed without obstmction. In embodiments, vent cover 112 is configured such that the inclined central surface region 114 is arranged at an angle substantially the same as the angle of lid portion 104 when in the removal configuration. In embodiments, inclined central surface region 114 is substantially parallel to the plane of edge portion 104a, when lid 104 is in the removal configuration. In this manner, the low profile of vent cover 112 enables efficient use to be made of the available space within the case of apparatus 100, thereby allowing the electrical equipment of apparatus 100 to be provided in a small volume case, whilst still facilitating removal of lid 104 from body portion 102, without requiring the removal of closure 108 or vent covers 112.

The above embodiments are to be understood as illustrative examples of the invention. Further embodiments of the invention are envisaged. For example, apparatus 100 may be provided without an electrical equipment, for the purpose of replacement parts, or to enable later inclusion of the electrical equipment. Similarly, closure 108 may be provided without the case, for the purpose of replacement parts, or to enable installation into a standard case model, Further, fan vents 112 may be provided in isolation, for the purpose of replacement parts, or for installation on an existing electrical apparatus or case. Similarly, any of the previously described subcomponents, such as filter portion 136 and filter cover portion 138 may be provided in isolation for the purpose of replacement parts. It is to be understood that any feature described in relation to any one embodiment may be used alone, or in combination with other features described, and may also be used in combination with one or more features of any other of the embodiments, or any combination of any other of the embodiments.

Furthermore, equivalents and modifications not described above may also be employed without departing from the scope of the invention, which is defined in the accompanying claims.

Claims

Claims 1. An electrical apparatus comprising: an electrical equipment; a case, comprising a body housing the electrical equipment; a closure, coupled to the body, for sealing the electrical equipment within the body, the closure having walls upstanding from the body, one of the walls being an inclined mounting surface comprising at least one ventilation opening for enabling airflow through the closure; and a convex vent cover covering the ventilation opening, the vent cover comprising: a sealing surface at least partially encircling the opening and sealed to the inclined mounting surface, an inclined central surface region; a ventilation surface region extending between a lower edge region of the vent cover and the inclined central surfkce region, the ventilation surface region comprising one or more orifices for permitting airflow through the vent cover, and an impeiforate surface region extending between the inclined central surface region and the sealing surface, the imperforate surface region being configured to encourage incident liquids away from the ventilation surface region.
2. An electrical apparatus according to claim 1, wherein the imperforate surface region further extends between the ventilation surface region and the sealing surface.
3. An electrical apparatus according claim 1 or 2, wherein the inclined central surface region comprises mounting means for coupling the vent cover to the inclined mounting surface.
4, An electrical apparatus according to claim 3, wherein the mounting means comprises a through-hole for a screw.
5. An electrical apparatus according to any preceding claim, wherein the inclined central surface region is arranged at an angle between 45 and 75 degrees to the horizontal.
6. An electrical apparatus according to any preceding claim, wherein the inclined central surface region is arranged at an angle between 55 and 65 degrees to the horizontal.
7. An electrical apparatus according to any of claims 1 to 5, wherein the inclined central surface region is arranged at an angle between 45 and 60 degrees to the horizontal.
8. An electrical apparatus according to any preceding claim, wherein the inclined central surface region is arranged at an angle of substantially 60 degrees to the horizontal.
9. An electrical apparatus according to any preceding claim, wherein the inclined central surface region is substantially parallel to the inclined mounting surface.
10. An electrical apparatus according to any preceding claim, wherein the ventilation surface region extends substantially vertically.
1]. An electrical apparatus according to any of claims I to 9, wherein the ventilation surface region extends at a negative incline.
12. An electrical apparatus according to any preceding claim, wherein the ventilation surface region comprises one or more guard portions configured to restrict access of an operator's fingers via the ventilation surface.
13. An electrical apparatus according to claim 12, wherein the one or more guard portions are configured to restrict access via the ventilation surface for objects with a diameter greater than 5mm.
14. An electrical apparatus according to claim 12 or 13, wherein the one or more guard portions are configured to restrict access via the ventilation surface for objects with a diameter greater than 2mm.
15. An electrical apparatus according to any preceding claim, wherein the sealing surface comprises a curved upper edge region, wherein the imperforate surface region extends to the curved upper edge region of the sealing surface.
16. An electrical apparatus according to claim 15, wherein a width of the lower edge region is greater than a width of the upper edge region.
17. An electrical apparatus according to claim 15 or 16, wherein the sealing surface comprises one or more side edge regions, extending between the curved upper edge region and the lower edge region, wherein the imperforate surface region extends between the inclined central surface region and the one or more side edge regions.
18. An electrical apparatus according to any preceding claim, wherein the vent cover is configured to maintain a predetermined minimum air and/or surface path length between the ventilation opening and the ventilation surface region.
19. An electrical apparatus according to claim 18, wherein the predetermined minimum air and/or surface path length comprises a distance of at least 20mm.
20. An electrical apparatus according to any preceding claim, wherein the vent cover comprises a filter portion, arranged to substantially cover the one or more orifices in the ventilation surface region.
2] An electrical apparatus according to claim 20, wherein the filter portion comprises a foam.
22. An electrical apparatus according to claim 20 or 21, wherein the filter portion comprises a material with a relatively high permeability to gasses and a relatively low permeability to liquids.
23. An electrical apparatus according to any of claims 20 to 22, wherein the filter portion comprises polyether polyurethane.
24. An electrical apparatus according to any of claims 20 to 23, wherein the filter portion is replaceable.
25. An electrical apparatus according to any preceding claim, wherein the fan vent comprises a lip portion, adjacent to the lower edge region.
26. An electrical apparatus according to claim 25, wherein the one or more orifices in the ventilation region extend around the lip portion.
27. An electrical apparatus according to any preceding claim, wherein at least a portion of the inclined central surface region is arranged within the projection of the ventilation opening in a direction perpendicular to the inclined mounting surface, 28. An electrical apparatus according to any preceding claim, wherein at least a portion of the ventilation surface region is arranged outside of a projection of the ventilation opening in a direction perpendicular to the inclined mounting surface.29. An electrical apparatus according to any preceding claim, comprising a lid, pivotally coupled to the inclined mounting surface, the lid being configurable into a closed configuration in which the inclined mounting surface is covered by the lid, and an open configuration in which the inclined mounting surface is exposed.30. An electrical apparatus according to claim 29, wherein the lid is further configurable into a removal configuration, the inclined central surface region being arranged at an angle substantially equal to the angle of the lid when in the removal configuration.31. An electrical apparatus according to any preceding claim, wherein the closure comprises a flange for fixing the closure to the casing.32. An electrical apparatus substantially in accordance with any of the examples as described herein with reference to and as illustrated by the accompanying drawings.33. An electrical apparatus according to claim 32, comprising a vent cover substantially in accordance with any of the examples as described herein with reference to and as illustrated by Figure 3, optionally as modified in accordance with Figures 5 or 6.34. A case for an electrical apparatus, the case comprising: a body; a closure, coupled to the body, the closure having walls upstanding from the body, one of the walls being an inclined mounting surface comprising at least one ventilation opening for enabling airflow through the closure; and a convex vent cover coveting the ventilation opening, the vent cover comprising: a sealing surface at least partially encircling the opening and sealed to the mounting surface; an inclined central surface region; a ventilation surface region extending between a lower edge region of the vent cover and the inclined central surface region, the ventilation surface region comprising one or more orifices for pennitting airflow through the vent coveç and an imperforate surface region extending between the inclined central surface region and the sealing surface, the imperforate surface region being configured to encourage incident liquids away from the ventilation surface region.35. A case for an electrical apparatus substantially in accordance with any of the examples as described herein with reference to and as illustrated by the accompanying drawings.36. A case for an electrical apparatus according to claim 35, comprising a vent cover substantially in accordance with any of the examples as described herein with reference to and as illustrated by Figure 3, optionally as modified in accordance with Figures 5 or 6.37. A convex vent cover for covering a ventilation opening on an inclined mounting surface of an electrical apparatus, the vent cover comprising: a sealing surface for at least partially encircling the opening, the sealing surface being sealable to the mounting surface; an inclined central surface region; a ventilation surface region extending between a lower edge region of the vent cover and the inclined central surface region, the ventilation surface region comprising one or more orifices for permitting airflow through the vent coveç and an imperforate surface region extending between the inclined central surface region and the sealing surface, the imperforate surface region being configured to encourage incident liquids away from the ventilation surface region.38. A vent cover substantially in accordance with any of the examples as described herein with reference to and as illustrated by Figure 3, optionally as modified by figures 5 and 6.AMENDMENTS TO THE CLAIMS HAVE BEEN FILED AS FOLLOWS: Claims 1. An electrical apparatus comprising: an electrical equipment; S a case, comprising a body housing the electrical equipment; a closure, coupled to the body, for sealing the electrical equipment within the body, the closure having walls upstanding from the body, one of the walls being an inclined mounting surface inclined at an acute internal angle with respect to the horizontal during normal operation of the electrical apparatus, the inclined mounting surface comprising at least one ventilation opening for enabling airflow through the closure; and a convex vent cover covering the ventilation opening, the vent cover comprising: a sealing surface at least partially encircling the opening and sealed to the inclined mounting surface, (3 an inclined central surface region, arranged substantially parallel to the 0 inclined mounting surface; 0 a ventilation surface region extending between a lower edge region of C") the vent cover and the inclined central surface region, the ventilation surface region comprising one or more orifices for permifting airflow through the vent cover, and an imperforate surface region extending between the inclined central surface region and the sealing surface, the imperforate surface region being configured to encourage incident liquids away from the ventilation surface region.2. An electrical apparatus according to claim 1, wherein the imperforate surface region further extends between the ventilation surface region and the sealing surface.3, An electrical apparatus according claim 1 or 2, wherein the inclined central surface region comprises mounting means for coupling the vent cover to the inclined mounting surface.4. An electrical apparatus according to claim 3, wherein the mounting means comprises a through-hole for a screw.5. An electrical apparatus according to any preceding claim, wherein the inclined central surface region is arranged at an angle between 45 and 75 degrees to the horizontal.6. An electrical apparatus according to any preceding claim, wherein the inclined central surface region is arranged at an angle between 55 and 65 degrees to the horizontal.(3 7. An electrical apparatus according to any of claims 1 to 5, wherein the 0 inclined central surface region is arranged at an angle between 45 and 60 degrees to the 0 horizontal.8. An electrical apparatus according to any preceding claim, wherein the inclined central surface region is arranged at an angle of substantially 60 degrees to the horizontal.9. An electrical apparatus according to any preceding claim, wherein the ventilation surface region extends substantially vertically.10. An electrical apparatus according to any of claims I to 8, wherein the ventilation surface region extends at a negative incline.11. An electrical apparatus according to any preceding claim, wherein the ventilation surface region comprises one or more guard portions configured to restrict access of an operator's fingers via the ventilation surface.12. An electrical apparatus according to claim 11, wherein the one or more guard portions are configured to restrict access via the ventilation surface for objects with a diameter greater than 5mm.13. An electrical apparatus according to claim 11 or 12, wherein the one or more guard portions are configured to restrict access via the ventilation surface for objects with a diameter greater than 2mm, 14. An electrical apparatus according to any preceding claim, wherein the sealing surface comprises a curved upper edge region, wherein the imperforate surface region extends to the curved upper edge region of the sealing surface.15. An electrical apparatus according to claim 14, wherein a width of the lower edge region is greater than a width of the upper edge region. (0O 16, An electrical apparatus according to daim 14 or 15, wherein the sealing C surface comprises one or more side edge regions, extending between the curved upper C") edge region and the lower edge region, wherein the imperforate surface region extends between the inclined central surface region and the one or more side edge regions.17. An electrical apparatus according to any preceding claim, wherein the vent cover is configured to maintain a predetermined minimum air and/or surface path length between the ventilation opening and the ventilation surface region.18. An electrica' apparatus according to claim 17, wherein the predetermined minimum air and/or surface path length comprises a distance of at least 20mm, 19. An electrical apparatus according to any preceding claim, wherein the vent cover comprises a filter portion, arranged to substantially cover the one or more orifices in the ventilation surface region.20. An electrical apparatus according to claim 19, wherein the filter portion comprises a foam.21. An electrical apparatus according to claim 19 or 20, wherein the filter portion comprises a material with a relatively high permeability to gasses and a relatively low permeability to liquids.22. An electrical apparatus according to any of claims 19 to 2], wherein the filter portion comprises polyether polyurethane.23. An electrical apparatus according to any of claims 19 to 22, wherein the filter portion is replaceable.24. An electrical apparatus according to any preceding claim, wherein the (0 fan vent comprises a lip portion, adjacent to the lower edge region.0 25. An electrical apparatus according to claim 24, wherein the one or more C") orifices in the ventilation region extend around the lip portion.26. An electrical apparatus according to any preceding claim, wherein at least a portion of the inclined central surface region is arranged within the projection of the ventilation opening in a direction perpendicular to the inclined mounting surface, 27. An electrical apparatus according to any preceding claim, wherein at least a portion of the ventilation surface region is arranged outside of a projection of the ventilation opening in a direction perpendicular to the inclined mounting surface.
28. An electrical apparatus according to any preceding claim, comprising a lid, pivotally coupled to the inclined mounting surface, the lid being configurable into a closed configuration in which the inclined mounting surface is covered by the lid, and an open configuration in which the inclined mounting surface is exposed.
29. An electrical apparatus according to claim 28, wherein the lid is frirther configurable into a removal configuration, the inclined central surface region being arranged at an angle substantially equal to the angle of the lid when in the removal configuration.
30. An electrical apparatus according to any preceding claim, wherein the closure comprises a flange for fixing the closure to the casing.
31. An electrical apparatus substantially in accordance with any of the examples as described herein with reference to and as illustrated by the accompanying drawings.
32. An electrical apparatus according to claim 31, comprising a vent cover substantially in accordance with any of the examples as described herein with reference (3 to and as illustrated by Figure 3, optionally as modified in accordance with Figures 5 O or6.CC) 33, A case for an electrical apparatus, the case comprising: a body; a closure, coupled to the body, the closure having walls upstanding from the body, one of the walls being an inclined mounting surface inclined at an acute internal angle with respect to the horizontal during normal operation of the electrical apparatus, the inclined mounting surface comprising at least one ventilation opening for enabling airflow through the closure; and a convex vent cover covering the ventilation opening, the vent cover comprising: a sealing surface at least partially encircling the opening and sealed to the mounting surface; an inclined central surface region arranged substantially parallel to the inclined mounting surface; a ventilation surface region extending between a lower edge region of the vent cover and the inclined central surface region, the ventilation surface region comprising one or more orifices for permitting airflow through the vent cover; and an imperforate surface region extending between the inclined central surface region and the sealing surface, the imperforate surface region being configured to encourage incident liquids away from the ventilation surface region.34. A case for an electrical apparatus substantially in accordance with any of the examples as described herein with reference to and as illustrated by the accompanying drawings.35. A case for an electrical apparatus according to claim 34, comprising a vent cover substantially in accordance with any of the examples as described herein (3 with reference to and as illustrated by Figure 3, optionally as modified in accordance O with Figures5or 6.CC1) 36, A convex vent cover for covering a ventilation opening on an inclined mounting surface of an electrical apparatus, the inclined mounting surface being inclined at an acute internal angle with respect to the horizontal during normal operation of the electrical apparatus, the vent cover comprising: a sealing surface for at least partially encircling the opening, the sealing surface being sealable to the mounting surface; an inclined central surface region, arranged to be substantially parallel to the inclined mounting surface when covering the ventilation opening; a ventilation surface region extending between a lower edge region of the vent cover and the inclined central surface region, the ventilation surface region comprising one or more orifices for permitting airflow through the vent cover; and an imperforate surface region extending between the inclined central surface region and the sealing surface, the imperforate surface region being configured to encourage incident liquids away from the ventilation surface region.37. A vent cover substantially in accordance with any of the examples as described herein with reference to and as illustrated by Figure 3, optionally as modified by figures 5 and 6.SCD