Patent Application
20090053990
This invention relates generally to the field of venting devices, and in particular, to venting devices for venting building enclosures.
Virtually all buildings and enclosures where human activity takes place require venting of one type or another. The type of venting device employed will depend on the kind of enclosure to be vented. For example, bathrooms containing showers typically have active vents with fans to vent steam to the outdoors. Kitchens, particularly in restaurants and hotels, similarly have powered vents for removing odours, smoke and steam to the outdoors.
Other types of enclosures, such as attics and yard sheds, do not require active venting. However, such enclosures do typically require a passive vent to allow for air flow from the enclosure to the atmosphere. Such venting is required, for example, to prevent a buildup of moisture in the enclosure. Passive vents do not include a mechanism for forcing air out of the enclosure. Rather, they simply include a vent structure, in the form of an air passageway which allows air to Flow through the vent structure.
Because passive vents simply allow air to Flow in and out through an opening in the enclosure, they typically include a screen that blocks animals or unwanted objects from entering the enclosure through the opening, but still allows air flow. The presence of the screen tends to reduce airflow area because the screen elements block some of the area through which air could flow.
Whether active or passive, the venting of an interior space of a building enclosure involves making a hole in the building envelope (e.g. the roof), and then covering the hole to prevent rain, snow and pests such as birds and animals from entering the enclosure through the hole, while at the same time permitting the passage of air into and out of the interior space of the building.
While there are many different types and designs of vents, both active and passive vents include some common elements, namely, a base for securing about the hole in the roof and a cover connected to the base, to prevent rain, snow or the like from entering the hole through the base. Typically the base has a nailing flange or flashing strip to attach the vent around the hole in the building enclosure, a grill across the hole to keep out unwanted pests while allowing air to pass through. The cover of such a vent prevents rain, snow or the like from impinging upon the grill. Typically the nailing flange of the vent is made larger than the hole formed in the building envelope, so that the vent can be fixed in place around the hole. For a sloped roof application, the flange is then underlapped and overlapped with, for example, roofing shingles, to provide for water shedding along the roof past the vent structure.
Passive vents are Well-known and have been extensively used. In the past, they have tended to be made from a metal such as galvanized steel or aluminum. Metal has certain advantages, including that it can be formed to exact shapes and according to precise specifications. Depending upon the metal, it is durable in the sense that aluminum, for example, is generally not degraded by exposure to the elements such as rain and sunlight. However, metal products can also be difficult to work with, expensive to form and fragile when formed in thin pieces. In a vent, the metal is not required to carry any significant loads. To save material and cost, therefore, thin metal is typically used. Thin sheet metal is easily bent; this feature facilitates the forming of the vent in the first place, but also means that the formed product can be damaged easily.
Thus, the thin sheet metal will be easy to bend into and then possibly out of the desired shape. Any bumps or knocks which typically occur during shipping can leave dents in the surface of the vent cover, which dents make the vent unacceptable to customers. Alternately, the base may become misshapen and twisted, making it difficult to attach the device onto a planar surface of the building enclosure, such as a roof. Sheet metal vents therefore tend to suffer from very high return rates due to delivery or other incidental damage.
More recently, plastic roof vents have been developed which are typically made by injection moulding or the like from thermoplastic resins, such as polypropylene. In this manner many units can be made quickly and for less cost than incurred in bending and forming sheet metal. Plastic roof vents are much more durable than metal ones during transportation, handling and delivery, since any bumps or blows inflicted will tend to be resiliently absorbed by the plastic without any lasting marking or damage. Unlike thin sheet metal, the plastic does not permanently deform under the range of stresses typically incurred in shipping. Therefore, the return rate for plastic vents is advantageously relatively low.
In a typical plastic vent, due to the complexity of its structure, the base and the cover need to be moulded separately. The base and cover are then attached together to form the finished vent. Accordingly, an important consideration in the design of such plastic vents is the structural connection between the cover and the base. Several known methods of attachment include screws, nails, clips, glue, sonic welding and heat staking.
A preferred mode of attachment is disclosed in U.S. Pat. No. 6,612,924, which involves using an attachment means in the form of four attachment structures, each comprising a shaft extending from a surface on the underside of the cover and a receptacle extending from the base. At its free end, the shaft has an arrowhead-shaped attachment head. At the free end of the receptacle is an aperture, which is configured to register with the corresponding attachment head. In operation, the cover is attached to the base by registering each attachment head with the corresponding aperture. The aperture of each receptacle flexes open to admit the matching attachment head. Once the head has been inserted beyond the aperture, the aperture, having a memory, returns to its pre-flexed size and closes around the head. Thus, the aperture catches the head at its upper end and is adapted to grip the head to prevent it from withdrawing from the receptacle. The result is that each shaft and receptacle lock together to form unitary pillars which hold and support the cover at a predetermined position above the base.
As shown in U.S. Pat. Nos. 6,155,008, and 6,520,852 the shafts and receptacles are integrally moulded to the base and cover in matching relation, with the shafts being attached to the underside of the top portion of the cover, and the receptacles being attached to the base. Although this means of attaching the cover to the base is quite effective, it suffers from some disadvantages. For example, it has been discovered that when several assembled vents are stacked one on top of the other for packaging and shipping to customers, the weight of the stacked vents on the lower most vents causes discolourations on the top portions of the covers of those lowermost vents at the points of attachment of the shafts.
Also, it is typical for vents like those described in the aforementioned patents to be made for use on sloped roofs. They have an upward end for facing up the roof, a downward end for facing down the roof, and two sides. Typically, the attachment structures are positioned between the vent structure and the sides. The result is that the side of the vent structure presents a complicated, jagged profile. When lapping the shingles over the flange at the sides, an installer must first cut out sections of the shingle corresponding to this jagged profile in order to install the shingles flush with the venting device. This additional step is time consuming and skipped by some installers, in which case a gap is created between the shingles and the venting device. This shortcut increases the chance that water will seep under the shingles and damage the roof.
Furthermore, passive vents may be required on a variety of different surfaces, such as level roofs or sloped roofs. In the case of steeply sloped roofs, water will flow down the slope at a high rate of speed. One problem that can arise in such a circumstance is that water flowing quickly down the sloped roof strikes the vent and splashes into the vent structure. This problem is particularly likely to occur during heavy rainfall, which would produce heavy water flow down the sloped roof. Similar heavy water flow might occur, for example, when snow and ice on the roof begin to melt. One attempt for overcoming this problem is disclosed U.S. Pat. No. 6,155,008, which discloses a passive venting device having a vent structure, which when viewed from above is generally rectangular, with three of its sides parallel to the sides of the outer attachment flange. However, the fourth side of the vent structure is slightly angled, forming a peak in the middle of the fourth side. When the passive venting device is mounted on a sloped roof, the passive venting device is positioned such that the peak is pointed up the slope. This positioning prevents water from pooling against the side of the vent structure.
Although the peak functions well in this regard, installation of a vent having this peak can be difficult, since the installer must cut the shingles at least twice in order to accommodate the jagged peak. This procedure risks overcuts, which may lead to damaging the shingle at the vicinity of the peak. If this happens, the shingles will not be flush with the upstanding side walls of the base, which is less than optimal.
A related problem is that, during times of heavy precipitation, raindrops can hit the roof and bounce under the cover and into the vent structure.
Therefore, what is desired is a passive venting device, which addresses one or more of the aforementioned problems with prior art venting devices, yet which is suitable for use at a variety of different locations on a roof. Preferably, the passive venting device provides increased airflow to and from the enclosure being vented and is simple and inexpensive to manufacture and install.
Accordingly, in one aspect of the present invention there is provided a vent for venting a building enclosure, the vent comprising:
a base comprising an attachment element for attaching the base to said building enclosure and an aperture to permit gas to pass in and out of said building enclosure through said base;
a cover for covering the aperture, the cover having a first cover portion and a second cover portion, the first and second cover portions being angled relative to one another; and
at least one attachment structure configured to attach the cover to the base, the attachment structure being carried by both the first and second cover portions.
In another aspect, there is provided a vent for venting a building enclosure, the vent comprising:
a base comprising an attachment element for attaching the base to said building enclosure and an aperture to permit gas to pass in and out of said building enclosure through said base, wherein the base includes sides configured to face sideways along a sloped roof, and at least one non-side portion;
a cover for covering the aperture; and
at least one attachment structure comprising an attachment member and a corresponding attachment receptacle for attaching the base and the cover, the attachment member being carried by one of the base and the cover, and the attachment receptacle being carried by the other of the base and the cover;
wherein one of the attachment member and the attachment receptacle that is carried by the base is positioned at said non-side portion.
Reference will now be made to the preferred embodiments of the present invention with reference, by way of example only, to the following drawings in which:
The present invention is described in more detail with reference to exemplary embodiments thereof as shown in the appended drawings. While the present invention is described below including preferred embodiments, it should be understood that the present invention is not limited thereto. Those of ordinary skill in the art having access to the teachings herein will recognize additional implementations, modifications, and embodiments which are within the scope of the present invention as disclosed and claimed herein. In the figures, like elements are given like reference numbers.
The base 12 includes a vent structure 16, including an aperture 18 (best seen in
However, particularly in conditions of heavy rain, it is preferred to prevent the rain falling onto the outer flange 20 from working its way under shingles which are lapped over the outer flange 20 along the side of the vent 10. This is accomplished in part providing the flange 20 with a rain ridge 22 along both sides, as shown in
Preferably, the base 12 comprises at least two sides 24 to face sideways along a sloped roof. The base 12 also preferably includes at least one non-side portion 26. Most preferably, the base 12 comprises a vent structure 16 including an aperture-surrounding wall 30, itself comprising vent structure walls 32, two of said vent structure walls 32 facing sideways along the sloped roof and functioning as the sides 24 of the base 12. Preferably, the at least one non-side portion 26 comprises a third vent structure wall 32 facing upward along the sloped roof, and a fourth vent structure wall 32 facing downward along the sloped roof.
In the preferred vent structure 16, the vent structure walls 32 surround the aperture 18 through the base 12 that permits gas to flow through the vent 10. A screen 38, configured to permit gas flow therethrough, is preferably associated with the vent structure 16 and aperture 18, and positioned to prevent unwanted material (e.g. rodents, refuse) to enter the aperture 18 from outside.
It is preferable that the aperture 18 be positioned within the aperture-surrounding wall 30, so that a top end 40 of the aperture-surrounding wall 30 will be spaced vertically from the roof when the vent 10 is installed thereon. As a result, the aperture-surrounding wall 30 presents a barrier to water flowing along the roof and prevents the water from entering the aperture and into the building enclosure. Instead, water flowing along the roof is simply deflected off of the aperture-surrounding wall 30, and flows away from the vent 10. It will further be appreciated that spacing the top end 40 of the aperture-surrounding wall 30 from the roof reduces the probability that rain will bounce off of the roof, under the cover 14 and through the aperture 18 into the building enclosure. This is because the top end 40 of the aperture-surrounding wall 30 presents a barrier to bouncing raindrops, reducing the risk that they will enter the aperture 18.
In the embodiment shown in
The screen 38 is preferably formed of vertical screen members 44 which provide relatively small spaces 46 between the screen members 44. These spaces 46 are sized such that unwanted objects such as birds, animals or debris are prevented from entering the aperture 18, whereas air, water vapour or gas can flow through the spaces 46 between the screen members 44. It will be appreciated by those skilled in the art that the presence of the screen members 44 has the effect of reducing the available air flow area through the aperture, as air can only flow through the spaces 46 between those screen members 44. To compensate for this, it is preferred to increase the surface area of the screen 38 to enhance air flow. One way of increasing surface area of the screen 38 is to form the screen 38 in the shape of a pyramid which extends upwardly from the top 40 of the aperture-surrounding wall 30, as best seen in the
It can now be appreciated by those skilled in the art that the aperture-surrounding wall 30 also acts as a screen spacer. That is, it spaces the screen 38 vertically away from the flange 20 and the roof. When the vent 10 is positioned on an intermediate portion of a sloped roof (i.e. between the roof ridge or apex and the roof edge), spacing the screen 38 away from the roof helps to prevent flowing water or rain from entering under the cover 14 and leaking through the aperture 18.
Preferably, the vent structure 16 also includes a liquid deflector 48 for use in situations where the vent 10 is mounted on sloped roofs. As best seen in
As shown in
Referring to
It will be appreciated that the attachment means and attachment structure(s) could take any appropriate form. What is important is that the vent 10 include one or more attachment structures to attach the cover 14 to the base 12 so that precipitation is blocked from entering the aperture 18 and gas flow through the aperture 18 is permitted.
As shown in
It will be appreciated that cover portions 58 and 60 can be angled relative to one another in a variety of ways. For example, in the embodiment of
As shown in
It will also be appreciated by those skilled in the art that the invention comprehends other attachment means not comprising the specific structure described above. What is important in this aspect of the invention is that the attachment means is carried by both the first and second cover portions 58,60, and secures the cover 14 to the base 12 while permitting the flow of gas through the aperture 18 and between the building enclosure and the outside. For example, the shafts 50 and receptacles 52 could be glued, screwed or heat-staked together. Also, other locking mechanisms besides the above-described openings 56 and arrowhead 50 shafts could be used. Similarly, it would be possible to use a different number of attachment structures, heads 54 or shafts 50. What is important is that the base 12 and the cover 14 are adequately secured to one another. Also, the attachment means should be carried by at least two cover portions 58,60 which are angled relative to one another, and should secure the cover 14 to the base 12 while permitting the free flow of gas through the aperture 18 and between the building enclosure and the outside.
Referring now to
As mentioned above, the base preferably includes four attachment receptacles 52, two of which are positioned at the upward end of the base 12 and the other two are positioned at the downward end. The attachment receptacles 52 may be formed integrally into the aperture-surrounding wall 30 of the vent structure 16, into the flange 20 apart from the vent structure 16, or any combination thereof.
Preferably, the vent structure 16 has a width W that is approximately the same width as a standard shingle tab—about 20.3 centimetres. In this way, once one shingle tab is cut out, the vent 10 will fit neatly between the remaining shingle tabs, resulting in a clean looking installation. No cutting off of portions of tabs is required.
Referring now to
While reference has been made to various preferred embodiments of the invention other variations are comprehended by the broad scope of the appended claims. Some of these have been discussed in detail in this specification and others will be apparent to those skilled in the art. All such variations and alterations are comprehended by this specification are intended to be covered, without limitation.
