Patent Abstract:
A roof ridge ventilator with filtering device to be installed under a cap shingle includes a one piece cover member of an elongated shape including a pair of flaps, each flap having one upper surface over which cap shingles are secured and also having downwardly facing lower surfaces, a pair of vents respectively secured to the lower surface of the cover member flaps, each vent including at least one set of shielded louvers having openings for deflecting air flow while maintaining a minimum free area for air passage such that the air flowing therethrough is substantially reduced in velocity to limit the infiltration of foreign matter. Longitudinally spaced supports extend substantially vertically to permit nailing onto the roof such that the vent does not collapse during installation and such that the net free area remains intact. A band of fibrous material positioned inboard of the vent to further prevent foreign matter for entering the attic.

Full Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to roof ventilator in general, and more particularly, to a device and method for filtering foreign matter from external air passing through the roof ventilator.  
           [0003]    2. Background  
           [0004]    Roof ridge ventilators permit circulation of air through the roof of a building to decrease the temperature within the building and to allow for air circulation under the roof. Such ventilators are also desirable for the removal of moisture build-up within the enclosed cavity of the roof to prevent rotting of wooden and/or composite members. Commonly, ridged roofs will have an opening at the ridge communicating with the cavity. Ideally, the roof ridge ventilators protect the opening from the external environment while allowing air to freely circulate through the cavity.  
           [0005]    Some currently available roof ventilators have external baffles used to deflect airflow away from the vents of the roof ventilator. That is, the external baffles do not filter air as it flows through the roof ventilator and, moreover, tend to be unsightly. In addition, other currently available ventilators use adhesives to attach various parts of the ventilator. Using adhesive tends to increase the complexity and cost of fabricating the ventilator. Moreover, adhesives tend to degrade relatively quickly over time due to the temperature cycling experienced by ventilators when installed, thereby decreasing the reliability of the ventilator.  
           [0006]    One proposed ventilator to overcome these problems is set forth in U.S. Pat. No. 5,070,771, issued to Mankowski. Mankowski discloses a ventilator that includes a pair of flap covers hingedly connected by a hinge member integrally formed with each flap cover. Extending at an angle from the lower surface of each flap cover is a set of internal louvers (i.e., the louvers are under the covers when the ventilator is installed on a roof. Each louver includes openings extending there-through to permit the exchange of air. In addition, the louvers serve to filter the air as it flows through the ventilator. Although such a ventilator effectively vents the enclosed cavity of a roof, of course, further improvements are desirable.  
           [0007]    One improvement that is desirable stems from recent changes in some state building codes. In response to extremely severe weather conditions, some state building codes have been amended to require that roof ventilators prevent infiltration of foreign matter into the enclosed roof cavity to which the ventilator is attached. A ventilator as disclosed in the aforementioned Mankowski patent meets such requirements for normal and even severe weather conditions. However, in extremely severe weather conditions (e.g., hurricanes), that ventilator may undesirably experience water leakage.  
           [0008]    Thus, there exists a need for a roof ventilator that permits the free exchange of air within the roof cavity at a relatively low cost and with a high degree of performance and reliability under extreme weather conditions.  
         SUMMARY OF THE INVENTION  
         [0009]    In accordance with the present invention, a roof ventilator is provided. The roof ventilator includes a cover member having a flap with a first surface over which shingles are secured and a second surface. The roof ventilator also includes a first set of louvers for deflecting airflow and reducing airflow velocity while maintaining minimum free area for air passage. Supports and a filter device are coupled to the cover member second surface. The supports extend from the second surface of the cover member flap at a height substantially equal to that of the first set of louvers to minimize interference with the first set of louvers by the supports. The filter device filters external air passing through the first set of louvers.  
           [0010]    In accordance with other aspects of this invention, the filter device is a band of fibrous material and has a thickness that is substantially equal to the height of the supports.  
           [0011]    In accordance with additional aspects of this invention, the filter device includes slits cut so as to be aligned with the supports when the filter device is attached to the cover member. The filter device is attached over the supports by the supports fitted into slits of the filter device.  
           [0012]    In accordance with still yet other aspects of this invention, the roof ventilator further includes a second set of louvers located inboard of the supports. The second set of louvers have openings for further deflecting and reducing air flow velocity while maintaining a minimum free area for air passage.  
           [0013]    A roof ventilator formed in accordance with the present invention has several advantages over roof ventilators used in the past. First, the filter device minimizes the passage of rain, insects, and dirt particles from entering the ventilated space while retaining the compact size and low cost of the roof ventilator. Second, the louvers deflect airflow while maintaining a minimum free area for air passage, such that the air flowing through the roof ventilator is substantially reduced in velocity to further limit the infiltration of foreign matter. Finally, because of its integrated design, a roof ventilator formed in accordance with the present invention can easily be manufactured and installed. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]    [0014]FIG. 1 is a perspective view of a roof ventilator formed in accordance with one embodiment of the present invention.  
         [0015]    [0015]FIG. 2 is a partial bottom planar view of a roof ventilator formed in accordance with one embodiment of the present invention showing the filter device, louvers, and supports.  
         [0016]    [0016]FIG. 3 is a cross-sectional end view of a roof ventilator formed in accordance with one embodiment of the present invention, showing placement and attachment of a filter device.  
         [0017]    [0017]FIG. 4 is a cross-sectional end view of a roof ventilator formed in accordance with another embodiment of the present invention, showing alternative attachment of the filter device.  
         [0018]    [0018]FIG. 4A is a cross-sectional end view of a roof ventilator formed in accordance with another embodiment of the present invention, showing other alternative attachment of the filter device.  
         [0019]    [0019]FIG. 4B is a cross-sectional end view of a roof ventilator formed in accordance with another embodiment of the present invention, showing yet another alternative attachment of the filter device.  
         [0020]    [0020]FIG. 5 is a cross-sectional end view of a roof ventilator formed in accordance with another embodiment of the present invention, showing alternative placement and attachment of the filter device.  
         [0021]    [0021]FIG. 6 is a cross-sectional end view of a roof ventilator formed in accordance with another embodiment of the present invention, showing other alternative placement and attachment of the filter device.  
         [0022]    [0022]FIG. 6A is a cross-sectional end view of a roof ventilator formed in accordance with yet another embodiment of the present invention, showing another alternative placement and attachment of the filter device.  
         [0023]    [0023]FIG. 7 is a cross-sectional end view of a support of a roof ventilator formed in accordance with another embodiment of the present invention, showing sidewall serrations. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0024]    [0024]FIGS. 1 and 2 illustrate one embodiment of a roof ventilator  20  constructed in accordance with the present invention. The roof ventilator  20  includes a cover member  22 , first and second louvers  24 A and  24 B, supports  26 , and a filter device  28 . Except for filter device  28  (described further below), roof ventilator  20  is suitably formed from a thermal plastic, such as polypropylene, or other materials such as nylon, epoxy resin, polyurethane or other plastics. Alternatively, roof ventilator  20  may be formed from a suitable metal such as aluminum or sheet steel.  
         [0025]    The cover member  22  includes first and second flaps  30 A and  30 B and a hinge  32  extending longitudinally between the first and second flaps  30 A and  30 B. The hinge  32  is suitably integrally formed with the first and second flaps  30 A and  30 B to form a unitary body. The construction of the cover member  22  permits use of the roof ventilator  20  on roof ridges of varying pitches and angles. The roof typically contains an opening for venting the roof cavity. The roof ventilator  20  may be of any length, but is suitably four to five feet. In one embodiment, the roof ventilator  20  may be secured to a roof ridge by a cap shingle (not shown) by a well-known fastener (e.g., a nail, screw, tack, staple or other types of fasteners) extending through both the cap shingle and the roof ventilator  20 .  
         [0026]    The first and second set of louvers  24 A and  24 B are suitably integrally formed with the cover member  22  and include openings  34 . Each opening  34  permits air circulation through the roof ventilator  20 . Further, each opening  34  deflects airflow while maintaining a minimum free area for air passage, such that air flowing through the louvers  24 A and  24 B is substantially reduced in velocity to limit the infiltration of foreign matter. The openings  34  change the direction of airflow through the roof ventilator  20 , such that airflow velocity within the roof ventilator  20  is reduced to substantially zero under normal conditions.  
         [0027]    Still referring to FIGS. 1 and 2, the supports  26  will now be described in greater detail. Each of the supports  26  are substantially rectangular and are integrally formed with the lower surface of the cover member  22 , such that, in this embodiment, each support  26  is substantially normal to the cover member  22 . The supports  26  are spaced at predetermined locations along the length of the roof ventilator  20  to minimize their impact on air flowing through the roof ventilator  20 . In this embodiment, at least one side of the roof ventilator  20  includes two rows of aligned supports, such that an inboard and outboard row of supports are disposed in space relationship on the lower surface of the cover member  22 . As configured, filter device  28  may be disposed between the spaced inboard and outboard rows of supports. Although in this embodiment, the supports  26  are rectangular in shape and extend normally from the surface of the cover member  22 , in other embodiments, the supports can extend from the cover member at any suitable angle or shape so long as the configuration does not interfere with the roof ventilator  20  being properly mounted to the roof.  
         [0028]    The filter device  28  is suitably formed from various fibrous materials, such as fiberglass, plastic fibers, natural fibers and coated natural fibers. The fibers may be loosely woven, or may be unwoven and held together with a binding material. In one embodiment, the fibrous material is the same as that used in SPEEDVENT vent products available from Northwest Building Products, Madison Heights, Mich. The fibrous material may include a backing or mesh on one or both sides to provide additional structural support for the filter device to hold its shape. In this particular embodiment, the filter device  28  is substantially rectangular in shape and may be adhesively or mechanically fastened between the inboard and outboard rows of the supports  26 . As fastened between supports of the supports  26 , the filter device  28  extends the length of the roof ventilator  20 . The filter device  28  further minimizes infiltration of foreign matter into the roof to which the roof ventilator  20  is mounted, while still allowing ventilation. In this embodiment, the filter device  28  is advantageously placed away from the opening in the roof ridge so that the fibrous material will not sag or otherwise fall into the roof ridge opening.  
         [0029]    Operation of the roof of ventilator  20  may be best understood by referring to FIG. 3. For clarity, this description is for one half of the ventilator (i.e., the half containing louvers  24 A), with the operation for the other half (i.e., the half containing louvers  24 B) being essentially identical. In ventilation operation (i.e., when conditions tend to allow air to flow out of the ventilator), air tends to flow from the roof ridge opening toward the cover member  22 . This airflow is typically caused by convection and/or external airflow over the roof (i.e., the shape of the ventilator along with the orientation of the louvers can cause a pressure differential that facilitates airflow out of the ventilator). In normal ventilation, air flows through the filter device  28  as indicated by the arrow  52 . The air passes through the filter device  28  and then through the louvers  24 , as indicated by an arrow  50 .  
         [0030]    Because the airflows and pressure differentials involved with ventilation are relatively small compared to those experienced during extreme weather conditions, it is desirable that the filter device impedes the ventilation airflow as little as possible while still providing the desired infiltration protection. Therefore, in accordance with the present invention, filter device  28  is formed into a relatively narrow band or strip of fibrous material. In conjunction with the internal louvers (e.g., louvers  24 A), the relatively narrow width of the band is sufficient to achieve infiltration performance to meet current extreme weather building codes while minimizing obstruction of ventilation airflow out of the roof. In one embodiment, the band is about 1.25 inches wide, but the width can be smaller or larger, depending on the density of the filter material, louver performance, and building code infiltration requirements. In view of the present disclosure, those skilled in the art can determine the suitable filter parameters to meet these requirements. The filter thickness preferably matches the height of the louvers. One advantage of this embodiment is that the louvers tend to filter out solid matter so that the filter device will not become clogged. Under extreme weather conditions when water may leak past the louvers, the filter device prevents this water from leaking into the roof ridge opening.  
         [0031]    In infiltration operation (i.e., when conditions tend to cause air to flow into the roof ventilator), as air passes through the openings  34  of the louvers  24 A, this air is deflected upward, following a course in the opposite direction of the arrow  50 . As a result, the free area through which air is permitted to pass is minimized, thereby substantially reducing both the velocity and infiltration of foreign matter of air passing through the louvers  24 A.  
         [0032]    After air passes through the louvers  24 A, this air passes through the filter device  28 , following a course that is opposite that of the arrow  52 . The filter device  28  further reduces passage of airborne foreign matter through the roof ventilator  20 . As a result, airborne matter within air passing through the roof ventilator  20  is filtered out through the louvers  24 A and the filter device  28 . As previously described, the louvers  24 A and the filter device  28  operate together to meet current extreme weather building codes while minimizing obstruction of ventilation airflow out of the roof.  
         [0033]    Referring now to FIG. 4, an alternate embodiment of a roof ventilator  120  formed in accordance with the present invention is illustrated. The roof ventilator  120  of this alternate embodiment is substantially identical in materials and operation as roof ventilator  20  (FIG. 3) described above, except that roof ventilator  120  includes a retainer  136 . Except for retainer  136 , the reference numbers used in describing features and elements of roof ventilator  120  are the same as those of roof ventilator  20  (FIG. 3), but preceded by a numeral “ 1 ” so that the description of roof ventilator  20  can be easily applied to roof ventilator  120 . Attachment of the filter device  128  may be had by a retainer  136  extending normally from the free end of the inboard row of supports  126 . The retainer  136  extends outboard from the free end of the inboard row of supports  126  to further assist in retaining the filter device  128  within the roof ventilator  120 .  
         [0034]    [0034]FIG. 4A illustrates a roof ventilator  120 A that is substantially similar to roof ventilator  120  (FIG. 4), except that roof ventilator  120 A has a retainer  166  that extends to the opposite support  126  (adjacent to louver  124   a ) instead of the shorter retainer  136  (FIG. 4). Support  126 A includes a fitting  168  that fits into a slot (not shown) on retainer  166 . In this embodiment, the fitting  168  has the shape of a tapered or angled flange and is formed from a substantially rigid yet resilient material. The flange is formed so that one side is tapered toward the distal end of the fitting  168  but the other side facing cover member  122  is flat. The resilient material and tapered side of the flange allows the fitting  168  to be fitted through the slot in retainer  166 , while the flat side of the flange prevents the retainer  166  from being moved away from support  126 A. This feature further aids in retaining filter device  128  in roof ventilator  120 A. Further, this feature can advantageously eliminate the need for adhesive to bond filter device  128  to the cover member  122 . Alternatively, the fitting  168  and the slot may be formed on the retainer  166  and support  126 A, respectively.  
         [0035]    [0035]FIG. 4B shows another alternative embodiment similar to that of FIG. 4A except that the retainer  155  does not overlap the support  126 A. Instead, in this embodiment, the retainer  166  is formed as integrally with support  126  and is folded over so that the end of the retainer  166  contacts the support  126 A. In this embodiment, a lip  170  is formed on the support  126 A. In this embodiment, the lip  170 , the retainer  166 , and the supports  126  and  126 A are formed from a resilient material, such as a plastic or polymer, that allows the retainer  166  to be bent over past the lip  170  after the filter device  128  is placed between the supports  126  and  126 A. That is, the end of the retainer  166  is forced past the lip  170  to be “snapped” into place, contacting and flush with the support  126 A. The retainer  166  together with the lip  170  serve to hold the filter device  128  in place.  
         [0036]    Referring now to FIG. 5, a second alternate embodiment of a roof ventilator  220  formed in accordance with the present invention is illustrated. The roof ventilator  220  is identical in materials and operation as the embodiment described above with the following exceptions described below. Except for the second set of louvers  270 , the reference numbers used in describing features and elements of roof ventilator  220  are the same as those of roof ventilator  20  (FIG. 3), but preceded by a numeral “ 2 ” so that the description of roof ventilator  20  (FIG. 3) can be easily applied to roof ventilator  220 .  
         [0037]    In this alternate embodiment, a second set of louvers  270 , a mirror image of the first set of louvers  228   a,  is located in a V-shaped configuration, such that the second set of louvers  270  extend from the base of the outboard set of supports at a predetermined angle to intersect the inboard set of supports. In this embodiment, the angle is about 25°, but any angle up to 90° can be used depending on the height and intersection point of the outboard set of supports. In this embodiment, the band of fibrous material for the filter device  228  includes slits  248  that are cut to a depth that is substantially equal to the height of the support, or deeper, or even all the way through the filter device  228 . The slits  248  run longitudinally and are suitably cut at a distance spaced from each other equal to the distance between each support. The filter device  228  is attached over the supports, with the slits  248  fitting snugly over each support  226 . Alternatively, the filter device may be attached to the cover member adjacent to or in the second set of louvers so that airflow into the roof ventilator must pass through two sets of louvers before flowing through the filter device.  
         [0038]    [0038]FIG. 6 illustrates a roof ventilator  320  formed in accordance with another embodiment of the present invention. The roof ventilator  320  is identical in materials and operation as roof ventilator  220  (FIG. 5) described above except that the single row of supports  226  adjacent to louvers  224 A is replaced with two rows of supports  326 A and  326 B. Except for these supports, the reference numbers used in describing features and elements of roof ventilator  320  are the same as those of roof ventilator  220  (FIG. 5), but incremented by  100 , so that the description of roof ventilator  220  (FIG. 5) can be easily applied to roof ventilator  320 .  
         [0039]    In this alternate embodiment, the row of supports  326 A is formed on part of the first set of louvers  324 A while the other row of supports  326 B is formed on the second set of louvers  370 . In this embodiment, the band of fibrous material for the filter device  328  is disposed between the rows of supports  326 A and  326 B. The filter device can be attached to the roof ventilator  320  by adhesive or mechanical fasteners. In a further refinement, retainers (not shown) as described above in conjunction with FIGS. 4 and 4B can be added.  
         [0040]    [0040]FIG. 6A illustrates a refinement of the embodiment of FIG. 6, with the supports  326 A and  326 B placed closer together. In this embodiment, the supports  326 A and  326 B are about  0 . 5  inches apart, although other distances can be used in other embodiments as required to match the width of the filter device. The fibrous material of the filter device  328  is placed between the supports. It is believed that the two sets of louvers in this embodiment allow the filter device  228  to be relatively narrow while still achieving the desired infiltration protection.  
         [0041]    [0041]FIG. 7 illustrates a support  426  formed in accordance with another embodiment of the present invention. As shown in FIG. 7, support  426  includes serrations  480  along a sidewall. The serrations  480  can have a spine-like, barb-like, spike-like shape, etc., with sharp points directed generally toward the cover member  422 . When the roof filter is assembled, the filter device (omitted for clarity) is adjacent to and contacting the serrations  480  of the support  426 . The serrations  480  tend to allow the filter device to move towards cover member  422  during assembly. In addition, the serrations  480  tend to prevent the filter device from moving away from cover member  422  by becoming enmeshed in the fibrous material of the filter device, thereby helping to fasten the filter device securely to the support  426 . These serrations can be provided in one or more of the supports of the embodiments depicted in FIGS.  3 - 6 .  
         [0042]    From the foregoing descriptions, it may be seen that a roof ventilator formed in accordance with the present invention incorporates many novel features and offers significant advantages over currently available roof ventilators. While the presently preferred embodiments of the invention have been illustrated and described, it is to be understood that within the scope of the appended claims, various changes can be made therein without departing from the spirit and scope of the invention.

Technology Classification (CPC): 5