Abstract:
An improved ventilation assembly for preventing fire and smoke from undermining a fire rated surface. The ventilation assembly includes a housing having at least one side wall defining an interior space, and a top wall coupled to the side wall, with an inlet adjacent the at least one side wall and an outlet coupled to the housing. A fluid, such as air, flows between the inlet and the outlet. A fire shielding material is disposed within the interior space, where the fire shielding material expands upon the application of a predetermined amount of heat such that the fire shielding material obstructs the flow of the fluid between the inlet and the outlet.

Description:
FIELD OF THE INVENTION  
         [0001]    This invention generally relates to ventilating exhaust fans, such as those typically utilized in bathrooms and other enclosed living spaces. More specifically, the present invention relates to a ventilating apparatus which includes an intumescent fire and smoke stop.  
         BACKGROUND OF THE INVENTION  
         [0002]    Ventilating exhaust fans, such as those typically included in bathrooms, draw air from within the enclosed area and pass the exhausted air out a vent in the gable or roof of the structure. Ventilation is thus provided for the enclosed living space. Typically, such exhaust fans include a rotating fan wheel having a plurality of vanes that create an outward airflow which, in turn, is directed out of an outlet opening by a curved fan scroll surrounding the fan wheel.  
           [0003]    To meet certain building codes, and to obtain approval from standards organizations, such as Underwriters Laboratories (UL), wall/ceiling exhaust fan designs now utilize a separately installed fire and smoke damper or other mechanical device which allows the exhaust fan to be installed into a fire or smoke rated ceiling or wall. Although such design may meet the codes and standards, they have drawbacks, however, in that this is a very expensive and inefficient way to achieve desired results. For instance, not only does the fan manufacturer have to provide both a specially sized and designed fire or fire and smoke stop to fit any number of fan models, but must also specially design housings which accept the standard fan assembly as well as the fire or fire &amp; smoke stop. In addition, the manufacture and distributor are now required to carry two different Stock Keeping Units (SKU&#39;s) for the same fan depending on whether the fan is to be installed into fire rated construction or not. Furthermore, it is expensive to produce a fan enclosure designed to accept current fire stop designs since the fan enclosure has to be significantly larger than a standard fan enclosure. Still further, conventional fire dampers depend upon a trigger mechanism which can fail at a critical time due to fatigue of the springs, relied upon to close the damper, or corrosion of the various parts over time.  
           [0004]    The present invention provides a standard fan housing design that can be economically manufactured and distributed in the field to be installed in both fire or fire and smoke rated ceilings and walls, or non rated walls and ceilings.  
           [0005]    Various other features, objects and advantages of the invention will become apparent from the following description taken together with the drawings.  
         SUMMARY OF THE INVENTION  
         [0006]    In view of the shortcomings of the prior art, the present invention provides an improved ventilation assembly which obstructs the flow of air, smoke and/or fire through the assembly.  
           [0007]    The ventilation assembly comprises a housing having at least one side wall defining an interior space, and a top wall coupled to the side wall; an inlet adjacent the at least one side wall; an outlet coupled to the housing, a fluid flowing between the inlet and the outlet; and a fire shielding material disposed within the interior space, the fire shielding material expanding upon the application of a predetermined amount of heat such that the fire shielding material obstructs the flow of the fluid between the inlet and the outlet.  
           [0008]    According to another aspect of the invention, the fire shielding material is an intumescent thermoplastic polymer.  
           [0009]    According to still another aspect of the invention, the fire shielding material is coupled to at least one of the side wall and the top wall.  
           [0010]    According to a further aspect of the invention, the assembly further comprising a fan motor assembly disposed within the interior space between the top wall and the inlet.  
           [0011]    According to yet a further aspect of the invention, the fire shielding material is disposed between the fan motor assembly and the inlet.  
           [0012]    According to another aspect of the invention, the fire shielding material is disposed between the fan motor assembly and the outlet.  
           [0013]    According to yet another aspect of the invention, the assembly is mounted in a fire rated surface.  
           [0014]    According to yet another aspect of the invention, a method for selectively allowing and preventing the flow of a fluid through a fire rated surface, comprises the steps of: forming a housing defining an interior space; coupling an inlet adjacent the housing means; coupling an outlet to the housing means, the fluid flowing between the inlet means and the outlet means; and disposing a fire shielding material within the interior space, the fire shielding material expanding upon the application of a predetermined amount of heat to obstruct the flow of the fluid between the inlet and the outlet.  
           [0015]    These and other aspects of the invention are set forth below with reference to the drawings and the description of exemplary embodiments of the invention.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0016]    The invention is best understood from the following detailed description when read in connection with the accompanying drawing. It is emphasized that, according to common practice, the various features of the drawing are not to scale. On the contrary, the dimensions of the various features are arbitrarily expanded or reduced for clarity. Included in the drawing are the following Figures:  
         [0017]    [0017]FIG. 1 is a cut away perspective view of an exemplary embodiment of the present invention;  
         [0018]    [0018]FIG. 2A is a side view of the exemplary embodiment of FIG. 1 illustrating the fire stop material in a pre-expanded condition;  
         [0019]    [0019]FIG. 2B is a side view of the exemplary embodiment of FIG. 1 illustrating the fire stop material in an expanded condition;  
         [0020]    [0020]FIG. 3A is a side view of a second exemplary embodiment of the present invention illustrating the fire stop material in a pre-expanded condition;  
         [0021]    [0021]FIG. 3B is a side view of the second exemplary embodiment of the present invention illustrating the fire stop material in an expanded condition;  
         [0022]    [0022]FIG. 4A is a side view of a third exemplary embodiment of the present invention illustrating the fire stop material in a pre-expanded condition;  
         [0023]    [0023]FIG. 4B is a side view of the third exemplary embodiment of the present invention illustrating the fire stop material in an expanded condition;  
         [0024]    [0024]FIG. 5A is a side view of a fourth exemplary embodiment of the present invention illustrating the fire stop material in a pre-expanded condition;  
         [0025]    [0025]FIG. 5B is a side view of the fourth exemplary embodiment of the present invention illustrating the fire stop material in an expanded condition; and  
         [0026]    [0026]FIG. 6 is a cut away perspective view of another exemplary embodiment of the present invention.  
     
    
       [0027]    It should, of course, be understood that the description and drawings herein are merely illustrative and that various modifications and changes can be made in the structures disclosed without departing from the spirit of the invention. Like numerals refer to like parts throughout the several views.  
       DETAILED DESCRIPTION  
       [0028]    When referring to the embodiments, certain terminology will be utilized for the sake of clarity. Use of such terminology is intended to encompass not only the described embodiment, but also technical equivalents which operate and function in substantially the same way to bring about the same result.  
         [0029]    Referring now more particularly to the drawings and FIG. 1 thereof, a partial cut-away view of a ventilation assembly  100  according to an exemplary embodiment of the present invention is shown. As illustrated, ventilation assembly  100  includes a housing  102  which is formed from side walls  104  and top wall  106 . Housing  102  has an interior space  112  defined by side walls  104  and top  106 . Top wall  106  may be formed form a separate piece of material from that of side walls  104 , or may be formed from a unitary piece of material. Either or both side walls  104  and top wall  106  may be formed from a metal, such a steel, and/or from a polymer, as desired. In its practical application, ventilation assembly  100  is installed in structure  125  (shown in FIG. 2A), such as a wall (horizontal mounting) or a ceiling (vertical mounting).  
         [0030]    Attached to housing  102  is inlet  108 , such as a grill assembly formed from a polymer or metal, that allows inlet air  114  to flow though lovers  109  and into interior space  112  of housing  102 . Also coupled to housing  102  is outlet  110  from which outlet air  116  passes. Within interior space  112  is motor assembly  120  (shown in FIG. 2A) to move air from the inlet  108  to the outlet  110 . Although as shown, outlet  110  has a generally circular cross section, the invention is not so limited, however, in that outlet  110  may have other cross sectional configurations, such as rectangular for example, to accommodate duct work or tubing (not shown) for exhausting outlet air  116  therethrough.  
         [0031]    In this exemplary embodiment, fire shielding material  118  is positioned on the inside surface of top  106 . In an exemplary embodiment of the present invention, fire shielding material  118  is an intumescent thermoplastic polymer, and may be provided in the form of sheets or as a liquid, for example. Fire shielding material  118  may be applied to top  106  using conventional means, such as with an adhesive having heat resistant properties or screws, for example, when provided in the form of sheets, or may be applied with a brush or sprayed on, for example, when provided in liquid form. For purposes of illustration, fire shielding material  118  is only partially shown. In the exemplary embodiment, however, fire shielding material  118  will cover a substantial portion of the inside surface of top  106  based on the expansion characteristics of fire shielding material  118 .  
         [0032]    Upon the application of a predetermined amount of heat (presumably from a fire), fire shielding material  118  expands within interior space  112  to obstruct the back flow of air into outlet  110  and out of inlet  108  to minimize the supply of air for feeding the fire. In addition, the expansion of fire shielding material  118  obstructs the flow of smoke and flame into interior space  112  and out through outlet  110 . In this way, the fire and smoke are not advanced through the fire rated structure (not shown) within which ventilation assembly  100  is installed.  
         [0033]    Referring now to FIG. 2A, a side view of the exemplary embodiment of FIG. 1 is shown. As illustrated, fan assembly  120  (which includes a motor  119  and fan blade  121 ) is mounted on venturi plate  122  within interior space  112  of ventilation assembly  100 . As shown in FIG. 2A, fire shielding material  118  is in an unexpanded (normal) condition. As such, low pressure inlet air  114  flows into inlet  108 , through venturi plate  122 , into fan blade  121 , and is ejected from outlet  110  as high pressure air  116 .  
         [0034]    Referring now to FIG. 2B, a side view of the exemplary embodiment of FIG. 1 is shown after the ventilation assembly is exposed to a source of excessive heat (not shown), such as a fire. As illustrated, fire shielding material  118 A has expanded within interior space  112  to substantially fill interior space  112 . As such, low pressure air  114  (or smoke and/or fire) is blocked by the expansion of fire shielding material  118 , as indicated by arrows  115 , and is unable to exhaust though outlet  110 . In this way the smoke and/or fire are unable to breech the fire rated structure into which ventilation assembly  100  is installed. As is known to those of skill in the art, motor assembly  120  may also include a thermal cut off to disable motor assembly  120  during a fire. It is important to note, however, that the expansion of fire shielding material  118  is not inhibited by the operation of fan assembly  120 , and may actually enhance the speed at which fire shielding material  118  expands during a fire event by spreading heat within interior space  112 .  
         [0035]    [0035]FIG. 3A illustrates a side view of a ventilation assembly  300  according to another exemplary embodiment of the present invention. This exemplary embodiment is similar to the first exemplary embodiment except that motor assembly  120  is mounted to top plate  106  and fire shielding material  318  is disposed on the upper surface of venturi plate  122 . As in the first exemplary embodiment, low pressure air  114  enters though inlet  108 , through venturi plate  122 , into fan blade  121 , and is ejected from outlet  110  as high pressure air  116 .  
         [0036]    [0036]FIG. 3B illustrates a side view of the exemplary embodiment of FIG. 3A after ventilation assembly  300  is exposed to a source of excessive heat. Similar to the first exemplary embodiment, upon the application of excessive heat fire shielding material  318 A expands in interior space  112  to obstruct the flow of air, fire and/or smoke between inlet  108  and outlet  110 .  
         [0037]    [0037]FIG. 4A illustrates a side view of ventilation assembly  400  according to yet another exemplary embodiment of the present invention. This exemplary embodiment is similar to the second exemplary embodiment except that outlet  410  is mounted to top plate  406  rather than to the side wall  404 . In addition, fire shielding material  418  may be mounted to either or both of the upper surface of venturi plate  422  and the inside of side wall  404 . As in the previous embodiments, low pressure air  114  enters though inlet  108 , through venturi plate  422 , into fan blade  121 , and is ejected from outlet  110  as high pressure air  116 .  
         [0038]    [0038]FIG. 4B illustrates a side view of the exemplary embodiment of FIG. 4A after ventilation assembly  400  is exposed to a source of excessive heat. Similar to the previous embodiments, upon the application of excessive heat, fire shielding material  418 A expands in interior space  412  to obstruct the flow of air, fire and/or smoke between inlet  108  and outlet  410 .  
         [0039]    [0039]FIG. 5A illustrates a side view of ventilation assembly  500  according to still another exemplary embodiment of the present invention. This exemplary embodiment is similar to the first exemplary embodiment except that outlet  410  is mounted to top plate  406  rather than to the side wall  404 . In addition, fire shielding material  418  may be mounted to either or both of the inner surface of top  406  and the inside of side wall  404 . As in the previous embodiments, low pressure air  114  enters though inlet  108 , through venturi plate  422 , into fan blade  121 , and is ejected from outlet  410  as high pressure air  116 .  
         [0040]    [0040]FIG. 5B illustrates a side view of the exemplary embodiment of FIG. 5A after ventilation assembly  500  is exposed to a source of excessive heat. Similar to the previous embodiments, upon the application of excessive heat, fire shielding material  418 A expands in interior space  412  to obstruct the flow of air, fire and/or smoke between inlet  108  and outlet  410 .  
         [0041]    Referring now to FIG. 6, ventilation assembly  600  is illustrated according to another exemplary embodiment of the present invention. This exemplary embodiment is similar to the previous exemplary embodiments expect that the configuration of housing  602  is generally circular having a substantially contiguous side wall  604 . Side wall  604  and top  606  define an interior space  612 . As illustrated in FIG. 6, fire shielding material  618  is partially shown disposed on the inside surface of top  606 . This embodiment is no so limited, however, in that fire stopping material  618  may be disposed on either the upper surface of venturi plate  622  and/or the inside surface of side wall  604 , in addition to or as a substitute for the placement of fire stopping material  606  as shown in FIG. 6.  
         [0042]    Upon the introduction of excessive heat, fire shielding material  618  expands into interior space  618 , similar to the previous exemplary embodiments described above, to obstruct the flow of air, smoke and/or fire through interior space  612  and out through outlet  610 .  
         [0043]    Although the invention has been described with reference to exemplary embodiments, it is not limited thereto. Rather, the appended claims should be construed to include other variants and embodiments of the invention, which may be made by those skilled in the art without departing from the true spirit and scope of the present invention.