Ventilation opening cowl

Abstract

A ventilation opening cowl (1, fig. 1) comprises a base 2 and a canopy 3 protruding from a front surface of the base and covering an opening 8 in the base. The base has a raised portion 4 at an edge o

Description

FIELD The present invention relates to a ventilation opening cowl, in particular for providing cover to airbricks. BACKGROUND Cowls over ventilation openings are commonplace in many industries. They are used to reduce draughts, prevent wind driven air ingress, prevent vents from being blocked by items resting against the wall and reduce noise. However, recent times have seen an increase in the use of Air Source Heat Pumps (ASHP) to heat domestic buildings. These heat pumps use propane as a refrigerant gas. In the unfortunate circumstances of a leak, propane poses explosion risks and can lead to asphyxiation. Since propane is heavier than air, it has a tendency to settle towards the ground and could enter a property through a ventilation opening provided for an underfloor void. It is suggested that a ventilation cowl can prevent or reduce such heavier-than-air gasses from entering the property through airbrick vents. Traditionally, cowls for airbrick vents are available in three sizes to suit commonly available airbrick ventilator size which are normally made in multiples of brick course size. A single course airbrick is commonly referred to as 9” x 3”; a double course airbrick 9” x 6”; and a triple course airbrick 9” x 9” (imperial inch dimensions). These are equivalent to 229mm x 76mm, 229mm x 152mm and 229mm x 229mm. Typically, these products are made by an injection mould process. To produce the range of different product sizes, three different mould tools would be required. Also, a supplier of the product would need to stock three products to meet the requirement of the marketplace. The present invention aims to mitigate at least one problem with existing ventilation opening cowls. SUMMARY OF INVENTION The present invention provides a ventilation opening cowl comprising, a base portion; a canopy portion protruding from a front surface of the base portion and covering an opening in the base portion; wherein, the base portion has a raised portion at an edge of the cowl in which a rear surface of the base portion is raised in the direction in which the canopy protrudes from the base portion, and wherein the rear surface of the raised portion is raised to at least the level of the front surface of another portion of the base portion which is at an opposite edge of the cowl. The raised portion means that when two cowls are overlapped, with the base portion of one (first) cowl between the wall and the raised portion of the other (second) cowl, the second cowl can sit flush with the wall and is not pushed away from the wall by the first cowl. The raised portion may be referred to as the overlapping portion, and the other portion at the opposite edge may be referred to as the underlapping portion. The raise portion is particularly advantageous. The raised portion acts as a step feature and the other portion of the base portion is configured to be received under the step feature. This enables a plurality of ventilation opening cowls to overlap so that they can be arranged to suit different ventilation opening sizes. Further advantageously, the step feature ensures that the plurality of ventilation openings is arranged to sit flush on the wall and prevent seepage of fluids into the ventilation opening from the sides. Preferably, the rear surface of the raised portion is raised to about the level of the front surface of the other portion of the base portion. Preferably, the canopy has an opening on one side of the cowl, and the raised portion is on the same side of the cowl. The canopy opening is typically at the bottom of the cowl in use, and so the raised portion is also typically at the bottom of the cowl in use. This is more effective at prevent water ingress than if the raised portion were at the top of the cowl. The raised portion may be positioned at a corner of the cowl. Two raised portions may be provided, each of which is at a respective corner of the cowl. When the cowl is fixed to a wall the rear surface of the base portion is configured to contact the wall. The ventilation opening cowl is configured to cover a ventilation opening. The ventilation opening may be in the form of an airbrick. The ventilation cowl may be installed at a ventilation opening for an underfloor void of a building. The ventilation opening for an underfloor void may be below an Air Source Heat Pump. In the unfortunate event of a propane gas leak from the Air Source Heat Pump, the heavier than air gas will tend to settle towards the ground. The canopy portion of the cowl is designed to direct the flow of these gasses away from the ventilation opening and towards the ground. This helps to reduce the ingress of these harmful gasses into the underfloor void. The raised portion of the base portion of the cowl may be raised by an amount substantially equal to a thickness of another portion of the base portion which is at an opposite edge of the cowl, the raised amount being measured from the rearmost portion of the base portion. The height of this step feature ensures that when two ventilation opening cowls are arranged by overlapping each other, the overlapped area of the overlapping cowl sits flush with the underlapping cowl. Such an arrangement ensures structural rigidity of an arrangement comprising a plurality of ventilation opening cowls. Preferably, the front surface of the other or another portion of the base portion has an opening or protrusion, and the rear surface of the raised portion of the base portion has a corresponding protrusion or opening, respectively, and the protrusion is small enough to be received in the opening. This means that when two cowls are overlapped, the protrusion of one can be received in the opening of another, which may hold the cowls in place relative to each other in the overlapped position. For any arrangement of the ventilation opening cowls as described above, the maximum protrusion away from the wall is the length of the extension of the canopy portion of the ventilation opening cowl. This not only enhances the aesthetics of the cowl installation but also ensures minimal protrusion compared to a ventilation cowl that has a longer canopy to meet certain ventilation opening dimensions. In particular, a conventional 9” x 6” cowl has a single canopy that protrudes further from the wall than the canopies of two cowls of the present invention which are overlapped. This is because the single cowl needs to provide the same airflow as the two overlapped cowls of the present invention. Similar to the raised portion of the base portion of the cowl, a portion of the canopy portion of the cowl may also be raised. The raised portion of the canopy portion of the cowl may be along a perimeter of the canopy portion that is furthest away from the base portion. The raised portion of the canopy portion may be adjacent to the raised portion of the base portion. Having the raised portion of the canopy portion may reduce the complexity of manufacturing the cowl. The dimensions of the ventilation opening cowls correspond to a single brick course size which is considered to be a ‘unit’ size. A single brick or ‘unit’ size is 9” x 3”. The different sizes of airbricks to which the ventilation opening cowl may be used would correspond to a multiple of this ‘unit’ size and therefore a plurality of ventilation opening cowls can be arranged to suit the size of the airbricks. For example, a 9”x6” airbrick or a double brick arrangement would require the arrangement of two ventilation opening cowls. Similarly, a 9”x9” airbrick or a triple brick arrangement would require an arrangement of three ventilation opening cowls. In a preferred embodiment of the present invention, the base portion includes a peripheral flange that extends in a direction opposite to the direction in which the canopy portion extends. The flange may provide the rear surface of the base portion. This flange is advantageous for two purposes. First, when the ventilation opening cowl is installed as a single unit, the flange ensures a flush fit to the wall and prevents fluids from entering from the sides. Secondly, when the ventilation opening cowl is installed in an arrangement with a plurality ofcowls, the flange encapsulates the interface where the two adjacent cowls join and further prevents fluid or other debris from entering the ventilation opening. Preferably, a section of the flange adjacent to the raised portion has an inner surface that is further from the opening in the base portion than (i.e. peripherally outward from) the outer surface of a section of flange which is adjacent to the other portion of the base portion at the opposite edge of the cowl. Preferably, the base portion comprises fastening means, which may comprise at least one fixing hole. The at least one fixing hole may be provided on a corner of the base portion. Preferably, a fixing hole is provided on the raised portion of the base portion. Preferably, a fixing hole is provided on the other portion of the base portion at the opposite edge of the cowl. The fixing hole on the raised portion may include a cylindrical protrusion which protrudes rearwards to provide a rear surface of the raised portion of the base portion. The length of the cylindrical protrusion may be substantially equal to the thickness of the other portion of the base portion. Preferably, a fixing hole is provided on a portion of the base portion other than the raised portion, and has a fixing hole having a diameter that is larger than a diameter of the fixing hole provided on the raised portion of the base portion. Fastening means such as fixing holes may be provided at at least one corner and preferably on two respective corners of the base portion of the cowl. The fixing holes are configured to receive fasteners such as nails, bolts, screws, etc. to affix the ventilation opening cowl to a wall firmly. Fixing holes may be provided respectively at all four corners of the cowl. The following features are preferred. The fixing hole provided on the raised portion of the base portion of the cowl is designed to mate with the other fixing hole provided on the other portion of the base portion. This is achieved by the cylindrical protrusion which protrudes rearwards. This cylindrical protrusion acts as a guide. The fixing hole on the other portion of the base portion is large enough to receive the cylindrical protrusion guide. The diameter of the fixing hole on the other portion of the base portion matches the outer diameter of the cylindrical protrusion. Further, the cylindrical protrusion has a length that is substantially equal to the thickness of the other portion of the base portion. The cylindrical protrusion may extend till it reaches a plane which includes the rearmost portion of the other portion of the base portion. This ensures that when the cylindrical protrusion mates with the other fixing hole provided on the other portion of the base portion and when this arrangement is installed on to a wall, structural integrity of the arrangement is maintained and the arrangement sits flush on the wall. Another advantage of the cylindrical protrusion is for when the ventilation cowl is used as a singular unit and not as part of an arrangement. The cylindrical protrusion encloses the fastener and along with the presence of a flange, reduces deterioration of the fastener. For example, a nail is less likely to corrode, as it is enclosed within the cylindrical protrusion it is not exposed to air or liquid and hence does not deteriorate. A distance between two adjacent fixing holes provided on the raised portion of the base portion and on the portion of the base portion other than the raised portion may be about 75mm. This helps to ensure that the fastener goes into the mortar joint of the brickwork and not directly into the brick. The structural integrity of the bricks (especially airbricks) is maintained during the installation of the ventilation opening cowl thereby. Preferably, the canopy portion and the base portion are integrally formed. The ventilation opening cowl may be made as a single part for easy installation without requiring further sub-assembly. This also simplifies and eases manufacturing. Preferably, the present invention relates to a method of manufacturing the ventilation opening cowl described herein via additive manufacturing. The method may comprise obtaining an electronic file representing a geometry of a product. The product may be the ventilation opening cowl described herein. The method may further comprise controlling an additive manufacturing apparatus to manufacture, over one or more additive manufacturing steps, the product according to the geometry specified in the electronic file. These and other preferred features of the present invention will now be described in further detail with reference to the accompanying drawings. DESCRIPTION OF DRAWINGS Figure 1 is a front perspective view of a ventilation opening cowl according to an embodiment of the present invention. Figure 2 is a cross-sectional view of two ventilation opening cowls according to an embodiment of the present invention. Figure 3 is a rear perspective view of the ventilation opening cowl of Figure 1. Figure 4 is a front perspective view of the two ventilation opening cowls of Figure 2. Figure 5 is a rear perspective view of the two ventilation opening cowls of Figure 2. Figure 6 is a front perspective view of three ventilation opening cowls according to an embodiment of the present invention. The present embodiment primarily relates to airbrick vents; however, it will be understood that such a cowl may equally be applied to other types of ventilation openings and other similar items. As such, any reference to airbricks, or an airbrick ventilation cowl is understood to cover uses with airbricks and other vent openings which may be covered in a similar manner. Figure 1 shows the ventilation opening cowl 1 according to an embodiment of the present invention. The cowl structure is formed of a base portion 2 and a canopy portion 3. The base portion is shaped like an inverted ‘U’. The base portion 2 is formed of three rectangular sub-portions, namely a (horizontal) base top sub-portion 2a, which is also the longest side; and two (vertical) base side sub-portions 2b and 2c, that run substantially perpendicular to the base top sub-portion 2a and extend in a direction from the base top sub-portion 2a. No part of the base portion 2 is provided in the area enclosed by the three sub-portions, thereby creating an opening 8 (see Figure 3). The design ensures that there exists an unobstructed path for ventilation. For example, the opening 8 may be placed over the ventilation openings in an airbrick. The base portion 2 has a front surface and a rear surface. The rear surface is configured to contact a wall when the cowl is fixed to the wall. The canopy portion 3 protrudes from the front surface of the base portion 2 and covers the opening 8 in the base portion 2. The canopy portion 3 is shaped like a right-angled prism and has softened or rounded edges to eliminate any sharpness. The canopy portion 3 is formed of three sub-portions - a canopy main plate 3a and two canopy side plates 3b and 3c. The canopy main plate 3a is a rectangular plate. The two canopy side plates 3b and 3c are right angle triangular plates. The canopy main plate 3a extends away from the front portion of the base top sub-portion 2a. Further, the canopy main plate 3a protrudes in an angle away from the base portion 2. A hypotenuse edge of the canopy side triangular plates is aligned with an edge of canopy main rectangular plate 3a. A first edge of the canopy side triangular plates is aligned with the edge of vertical base side sub-portions 2a, 2b. The resulting three dimensional right-angled prismatic shape is hollow and covers the airbrick ventilation opening to ensure unhindered airflow whilst providing protection from external factors. For example, the canopy may prevent heavier than air gasses and other wind driven air ingress from entering the airbrick ventilation opening. The sub-portion 2a, 2b and 2c of the base portion each comprise a main plate whose major surfaces face forwards and backwards, respectively. Also shown in Figure 1 is a raised portion 4 of the base portion 2 in which a rear surface of the base portion 2 is raised in a direction in which the canopy 3 protrudes from the base portion 2. In the present embodiment, the front surface in the raised portion 4 is raised in the same direction. The raised portion 4 is positioned at a bottom edge of the cowl 1. A space is formed behind the raised portion 4 which is open to the edge (bottom edge in this case) of the cowl 1. Although not shown in Figure 1, another raised portion is provided on the other side of the cowl 1 (also at the bottom edge of the cowl 1) which is a mirror image of the raised portion 4 shown in Figure 1. Both raised portions 4 are at respective corners of the cowl 1. In addition, the base portion 2 includes a peripheral flange that extends from the peripheral edges of the main plates of the base portion 2 rearwards until it reaches an imaginary wall surface plane which represents the wall surface. The flange is provided all around the perimeter of the base portion 2. The raised portion 4 has its own section of peripheral flange 4a. This flange 4a of the raised portion 4 has an inner surface that is further outwards to the side than the outer surface of the flange of the rest of the base portion 2. This allows the flange 4a to accommodate a portion of the flange of the rest of the base portion 2 when two cowls are arranged to overlap one another. Also shown in Figure 1 is a portion 3f of the canopy portion 3 on the front side of the cowl 1 which is also raised in a direction in which the canopy protrudes from the base portion. Figure 2 shows an arrangement of two overlapping ventilation opening cowls according to an embodiment of the present invention. A (bottom or overlap) fixing hole 5 is provided respectively on each raised portion of the base portions 4. A (top or fitting) fixing hole 7 is provided at each upper corner of the base portion 2. Each bottom fixing hole 5 is designed to mate with the top fixing holes 7. The fixing holes 5 each have a cylindrical protrusion 6 that extends from the rear of the base portion which is raised. The protrusion 6 extends till it reaches the wall surface plane. The outer diameter of the cylindrical protrusion 6 that extends from the fixing holes 5 is d 1. The fixing hole 5 provided on the raised portion of the base portion 4 of the cowl 1 has a countersink 5a that has a slightly larger diameter and allows the head of a nail or screw to sit flush with or below the front surface of the base portion 2 of the cowl 1. Also shown in Figure 2 is the other fixing holes 7 that are generally provided on the base top sub-portion 2a of the base portion 2. The fixing holes 7, similar to fixing holes 5, have a countersink 7a that has a slightly larger diameter than the countersink 5a of fixing holes 5. The fixing hole diameter d2 of the fixing holes 7 is slightly larger than the outer diameter d1 of the cylindrical protrusion 6 of the fixing holes 5. Therefore, the protrusion 6 can fit inside the fixing hole 7. This ensures when the protrusions 6 of an overlapping cowl 1are inserted into the fixing holes 7 of an underlapping cowl 1, the complementary features of the fixing holes 5, 7 allow the holes to be in assembly with each other. Like fixing holes 5, fixing holes 7 each have a cylindrical protrusion 9 that extends rearwards from the main plate of the base portion 2. The protrusion 6 extends till it reaches the imaginary wall surface plane. Both protrusions 6 and 9 extend that far to contact the wall and help prevent the main plates flexing rearwards when the fastener is tightened in the hole 5. In Figure 2, the left hand cowl 1 is identical to the right hand cowl 1. As can be seen in Figure 2, the raised portion 4 of the right hand cowl 1 is raised by an amount substantially equal to a thickness of the portion of the base portion 2 which is at the opposite edge of the cowl 1. This can be seen from the thickness of the base portion 2 of the left hand cowl 1 which underlaps the raised portion 4 of the right hand cowl 1. The raised amount is measured from the rearmost portion of the base portion, that is from the wall surface plane. The canopy 3 has an opening 10 on one side of the cowl 1, and the raised portion 4 is on the same side of the cowl 1. Figure 3 shows the ventilation opening cowl 1 according to an embodiment of the present invention. The length of the ventilation opening cowl I2 may be about 250mm to correspond to the length of a standard brickwork unit. The height of the ventilation opening cowl 11 may be about 90mm to correspond to the height of a standard brickwork unit. The distance between two adjacent fixing holes, one provided on the raised portion 4 of the base portion 2 and the other on the corner of the base portion 2 may be about 75mm. This helps to ensure that the fastener goes into the mortar joint of the brick work and not directly into the brick. The structural integrity of the bricks (especially airbricks) is maintained during the installation of the ventilation opening cowl. Figure 4 shows two ventilation opening cowls 1 being arranged to cover a double brick assembly. The air ventilation cowls 1 are arranged by overlapping each other as described above. The resulting arrangement is suitable for a 9” x 6” double brick unit and the canopy portion 3 does not protrude as extensively as would have been the case with a similar sized air ventilation cowl according to the prior art. Figure 5 is a rear view of the two cowls 1 of Figure 4. This shows the flange 4a of the raised portion 4 of the upper cowl 1 accommodating a portion of the flange of the base portion 2 of the lower cowl 1. Figure 6 shows three ventilation opening cowls being arranged to cover a triple brick assembly. The air ventilation cowls 1 are arranged by overlapping each other as described above. The resulting arrangement is suitable for a 9” x 9” triple brick unit and the canopy portion 3 does not protrude as extensively as would have been the case with 5 a similar sized air ventilation cowl according to the prior art. In the present embodiment the cowl 1 is formed of a plastics material, in particular polypropylene. 10 A preferred embodiment of the invention has been described purely by way of example, and various modifications, additions and / or omissions will present themselves to one skilled in the art, all of which form part of the invention.

Claims

1. A ventilation opening cowl, comprising:a base portion;a canopy portion protruding from a front surface of the base portion and covering an opening in the base portion;wherein, the base portion has a raised portion at an edge of the cowl in which a rear surface of the base portion is raised in the direction in which the canopy protrudes from the base portion, andwherein the rear surface of the raised portion is raised to at least the level of the front surface of another portion of the base portion which is at an opposite edge of the cowl.

2. A cowl according to claim 1, wherein the canopy has an opening on one side of the cowl, and the raised portion is on the same side of the cowl.

3. A cowl according to claim 1 or 2, wherein the raised portion of the base portion is positioned at a corner of the cowl.

4. A cowl according to claim 1, 2 or 3, wherein the front surface of the other or another portion of the base portion has an opening or protrusion, and the rear surface of the raised portion of the base portion has a corresponding protrusion or opening, respectively, and the protrusion is small enough to be received in the opening.

5. A cowl according to any preceding claim, wherein the base portion includes a peripheral flange that extends in a direction opposite to the direction in which the canopy portion extends.

6. A cowl according to claim 5, wherein the flange provides the rear surface of the base portion.

7. A cowl according to claim 5 or 6, wherein a section of the flange adjacent to the raised portion has an inner surface that is further from the opening in the base portion than the outer surface of a section of flange which is adjacent to the other portion of the base portion at the opposite edge of the cowl.

8. A cowl according to any preceding claim, wherein the base portion comprises fastening means.

9. A cowl according to claim 8, wherein the fastening means comprises at least one fixing hole.

10. A cowl according to claim 9, wherein the at least one fixing hole is provided on a corner of the base portion.

11. A cowl according to claim 9 or 10, wherein a fixing hole is provided on the raised portion of the base portion.

12. A cowl according to claim 11, wherein the fixing hole on the raised portion includes a cylindrical protrusion which protrudes rearwards to provide a rear surface of the raised portion of the base portion.

13. A cowl according to claim 12, wherein the length of the cylindrical protrusion is substantially equal to the thickness of the other portion of the base portion.

14. The cowl according to claim 11, 12 or 13, wherein a fixing hole is provided on a portion of the base portion other than the raised portion, and has a fixing hole having a diameter that is larger than a diameter of the fixing hole provided on the raised portion of the base portion.

15. A cowl according to claim 14, wherein a distance between two adjacent fixing holes provided on the raised portion of the base portion and on the portion of the base portion other than the raised portion is about 75mm.

16. A cowl according to any preceding claim, wherein the canopy portion and the base portion are integrally formed.

17. A computer program comprising computer executable instructions that, when executed by a processor, cause the processor to control an additive manufacturing apparatus to manufacture the cowl of any of any preceding claim.

18. A method of manufacturing a device via additive manufacturing, the method comprising:obtaining an electronic file representing at least the surface configuration of5 product, wherein the product is cowl according to any one of claims 1 to 16; andcontrolling an additive manufacturing device to manufacture, over one or more additive manufacturing steps, the product according to the surface configuration specified in the electronic file.15

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