Abstract:
A fireproof louver panel includes a panel frame and a plurality of longitudinally extending slats attached to the panel frame. One or more of the slats has a shell and an intumescent layer that expands under heat to form an airtight seal. A fireproof door or window may include an external frame, an internal core of a fireproof material (among other materials), and one or more such fireproof louver panels. A method of fireproofing an opening includes affixing a movable fireproof closure in the opening, and placement intumescent layers on the closure and on louvers disposed therein so that the opening is sealed when the first intumescent layer and the second intumescent layer are both subjected to heat.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application claims the benefit of U.S. Provisional Patent Application No. 60/802,171, filed May 22, 2006, the contents of which are hereby incorporated herein by reference in their entirety. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     This invention relates to building closures, such as doors and windows, in general, and relates to fireproof closures in particular.  
         [0004]     2. Related Art  
         [0005]     A fireproof door or window is a self-closing barrier designed to prevent the penetration of fire and smoke in through openings in walls for a given period of time. As used herein, the term “fireproof” refers to this ability to prevent the penetration of fire and smoke in through openings in walls for a given period of time, and not to any absolute ability to stop fires from spreading for an extended time.  
         [0006]     There are many types of fireproof doors which are currently available. These doors are entitled to a fireproof rating based on criteria established by various standards setting organizations, such as the Underwriter&#39;s Laboratories, Inc. (UL). Typically, the doors must pass a burn test that is applied to one side of a door at a specified high temperature for a certain period of time while keeping heat from the other side of the door. However, in addition to keeping out the heat, in practical applications the doors must also keep smoke from passing through the door opening. As is well known, it is usually smoke inhalation that people die from in fires. Both requirements are difficult to achieve while at the same time retaining the primary function of a door, which is to be operable to permit egress between the spaces the door divides. If the door is too tight against its frame, then it is difficult to operate. If the door is made of a nonflammable material, such as metal or concrete, then it becomes heavy and is usually not conducive to a decorative environment. Thus, as with most doors, there is always a compromise in door thickness, materials and overall weight in order to achieve a certain level of fireproofing (for example, a fire-resistance time, such as 90 minutes).  
         [0007]     Prior art fireproof doors usually include an exterior frame and covering with an internal core. Such doors can use an internal insulation layer consisting of compressed fireproof materials which practically fill out the space within the frame of the door. These known fireproof doors are relatively expensive and can be so heavy in weight that they can be opened and closed only with extreme effort. Another type of door uses an insulation layer made of an elastic, flexible, fireproof textile fabric fixed inside of a metal frame. See for example U.S. Pat. No. 4,270,326, which is incorporated herein by reference in its entirety.  
         [0008]     Some modern fire proof doors use an intumescent material, such as one made from hydrated sodium silicate, which expands with the development of foaming pressure as a reaction to heat. Other intumescent materials include foaming/expanding graphite; and poly-ammonium phosphates. When heated, such as by a fire, a fine-porous, compression-resistant, non-combustible, and heat-sealing foam is formed. This foam fills joints and gaps in the immediate vicinity, and thus prevents the penetration of fire and smoke for a certain period of time. The material can be obtained commercially in sheets, or can be “blown in” as a powder. For example, this material has been used as an edge band in regular doors and French doors, so as to seal the space between a closed door and its frame where there is a fire. Thus, where intumescent strips or sections of the material have been attached onto or inserted into the edges of wooden or steel doors, gateways, and flaps, in the event of a fire, they rapidly expand and reliably seal off joints and gaps in a short time.  
         [0009]     Most fire proof doors are solid, because the prior art teaches that the thicker the door, the greater will be the effectiveness of the door as a fire door, and consequently the greater will be the fire rating. Unfortunately, thicker doors and solid doors are often heavy, and can be expensive. Also, the artistic level of such doors is also quite limited. For example, there is a teaching away from the use of doors that have louvers and other ventilation structures, since ventilation openings are thought to make a door unusable as a fireproof door. Conventional wisdom suggests that a louvered or otherwise ventilated or vent-providing, door cannot function as an effective fire door. There is no known louvered door that can be thought of, much less labeled as, a wooden fireproof louver door. Moreover no louver itself are known to have been fire-rated and installed in a fireproof door.  
       SUMMARY OF THE INVENTION  
       [0010]     The presently disclosed apparatus, systems, and methods solve the problem of providing a door with both a ventilation function and a fireproof function. The present disclosure teaches a door that can be economically manufactured. Such a door is attractive and readily available for decorative applications, provides the expected air flow during normal times, is rugged and solid, yet is relatively light weight for a fire proof door. The present disclosure, for the first time, teaches a fireproof louvered door.  
         [0011]     The present disclosure teaches a fireproof louver panel that comprises a panel frame and a plurality of longitudinally extending slats attached to the panel frame. One or more of the slats comprises a shell and an intumescent layer that expands under heat to form an airtight seal. In some aspects, the longitudinally extending slats have a thickness, angle, and spacing sufficient to form said airtight seal when subjected to heat. As non-limiting examples, the thickness may be from 0.05 to 0.5 inches, or may be about 0.25 inches, the angle may be from about 30 degrees to 75 degrees, or may be about 60 degrees, and the spacing may be from 0.05 to 0.5 inches, or may be about 0.25 inches.  
         [0012]     In some aspects, the longitudinally extending slats are perpendicular to the plane of the door and have a thickness and spacing sufficient to form an airtight seal when subjected to heat. In some aspects, the shell comprises at least one opening through which the intumescent layer expands under heat. The opening may be shaped to cause the intumescent layer, when under heat, to expand in the plane of the door. In some aspects, the shell breaks open when the intumescent layer expands under heat. In some aspects, the intumescent layer is inside an inner cavity of the shell.  
         [0013]     In some aspects, the shell has an upper layer and a lower layer, and the slat comprises an outer skin which surrounds the upper layer, the lower layer, and the intumescent material. In some aspects, the outer skin comprises a wrapping material structurally configured to open at a chosen location during expansion of the intumescent layer.  
         [0014]     The intumescent material may, as non-limiting examples, be selected from hydrated sodium silicate; foaming graphite; expanding graphite; poly-ammonium phosphates; and combinations thereof.  
         [0015]     In some aspects, the intumescent material forms a non-combustible heat-sealing foam when heated. In some aspects, the slats are jalousie-type slats.  
         [0016]     The present disclosure also teaches a fireproof door having an external frame, an internal core of a fireproof material (among other materials), and a fireproof louver panel. In some aspects, a further intumescent layer is disposed at the outside of the external frame, and the intumescent material and the further intumescent material provide an airtight seal extending beyond the dimensions of the external frame. In some aspects, the door has a window disposed in a window opening, and a fireproof louver panel is disposed in the window opening adjacent the window.  
         [0017]     The present disclosure further teaches a fireproof window having an external frame, a flat translucent internal core of a fireproof material (among other materials), and a fireproof louver panel adjacent a flat side of the flat translucent internal core.  
         [0018]     The present disclosure teaches a method of fireproofing an opening. A movable fireproof closure is affixed in the opening. The closure has a first intumescent layer attached at the exterior of the closure and a panel frame within the closure. The panel frame has attached to it one or more longitudinally extending slats having second intumescent layer. Placement of the first and second intumescent layers is then configured so that the opening is sealed when the first intumescent layer and the second intumescent layer are both subjected to heat.  
         [0019]     The present disclosure also teaches a system for fireproofing an opening in an otherwise fireproofed door. The system has means for supporting longitudinally extending slats in the opening; and means disposed within the slats for expanding under heat to form an airtight seal. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0020]     With reference now to the drawings in which like numbers represent like elements throughout the several views:  
         [0021]      FIG. 1  is a front perspective view of a door having a louver panel in both the upper door portion and the lower door portion;  
         [0022]      FIG. 2  is front elevational view of a louver panel according to the present disclosure;  
         [0023]      FIG. 3  is a schematic side elevational view showing the spacing and details of the louver slats;  
         [0024]      FIG. 4  is an enlarged cross-sectional view of one of the louvers according to the present disclosure;  
         [0025]      FIG. 5  is an enlarged perspective view of two seated louvers; and  
         [0026]      FIG. 6  is an enlarged cross-sectional view of a second aspect of a louver panel in accordance with the present disclosure. 
     
    
     DETAILED DESCRIPTION  
       [0027]     A louvered door  10  according to the present disclosure is depicted in  FIG. 1 . Door  10  comprises a frame  12 , a door knob  14 , and upper and lower louver panels  16  and  18 , respectively, in accordance with the present disclosure. It is noted, however, that a louver panel may be placed in only the bottom of the door (as is traditionally done), in the top of the door, in both the bottom and top of the door, or any other region of the door. Door  10  can be made of any contemporary material such as wood, metal, plastic or fiber board. Further, door  10  can be of any style, such as the door depicted in  FIG. 1 , or a panel door, or any other kind of door.  
         [0028]     Louver panels  16  and  18  as shown are identical, and thus only panel  16  will be discussed further. As shown in  FIG. 2 , panel  16  is comprised of a circumferential frame  20  and a bisecting vertical mid-support member  22 . Frame  20  has an upper and a lower board  24  and  26 , and a left and a right end board  28  and  30  that are rigidly, fixedly attached at their respective ends to the adjacent boards so as to form a unitary, rigid, rectangular, hollow frame. Mid-support member  22  has a number of openings (not shown) which extend completely through it in the longitudinal direction. Through each opening there is a longitudinally extending slat  32  that is embedded at each end thereof in corresponding openings in end boards  28  and  30 . Slats are rigidly fixed in end boards  28  and  30  in a conventional way, such as one or more of an adhesive or a mechanical fastener, such as nails, pins, staples, screws, and dowels. Alternatively, they can just be force-fitted into an appropriately sized opening  34 . Although slats  32  are depicted as being flat, they could also have an inverted “V” shape with equal length arms or different length arms, or be any other slat shape known in the art, so long as room is provided for expansion of the slat in at least one dimension, as will be described below.  
         [0029]     Frame  20  is preferably made out of a good quality hardwood, such as oak, or maple, but it could also be made from High Density Fiberboard (HDF) or Medium Density Fiberboard (MDF) materials and covered with a veneer. In addition, frame  20  could be made of a metal or plastic material. An exemplary dimension of mid-support member  22  is a width of a quarter of an inch (0.25″) and a length that can vary with the design of louver  16 , but in  FIG. 2  is 11.5 inches. Exemplary dimensions of top and bottom boards  24  and  26  members are a length of twenty-four inches and a thickness of a quarter of an inch. The width of member  22  and boards  24 ,  26 ,  28  and  30  are usually the same, varying with the thickness of door  10 , but are usually one inch to two inches. In  FIG. 3 , board  30  may, as a non-limiting example, be 1.75 inches wide. Slats  32  are usually set at an angle with the horizontal so that one cannot see through door  10 . In  FIG. 3 , this angle is sixty degrees (601) and the spacing or distance along a vertical line, such as line  36 , is 0.5 inches. Another popular angle of slats  32  is forty degrees (401), in which case the vertical spacing along a vertical line would be 0.653 inches. However, they could also be parallel to upper and lower boards  24  and  26  (that is, perpendicular to the plane of the door), as in the case when louver  16  is in a window opening. Slats  32  may be given a length of exactly that of frame  16  if they extend completely through end boards  28  and  30 , or a few sixteenths of an inch less if they do not, or any other necessary length. Slats  32  have an exemplary thickness of a quarter of an inch (0.25″) and a spacing of 0.125 inches, but as explained below, the spacing can vary depending upon the constitution of slat  32  and on any intumescent material therein. For example, in  FIG. 3 , slats  32  have a spacing of a quarter of an inch (0.250″). The length of slats  32  in  FIG. 3  is 1.75 inches, but that length will vary with the angle and the thickness of frame  20 . As shown in  FIG. 4 , each slat  32  comprises a shell  40  and an inner stuffing  42 . Shell  40  completely surrounds stuffing  42  on five sides, but is open on one side. Shell  40  is preferably made of a hardwood, but could be made of a metal material, such as steel, or a plastic material. Such a plastic material, if used in a fire door, must be carefully chosen so as not to melt in a hot fire. This is also true of member  22  and boards  24 ,  26 ,  28  and  30 . Shell has an exemplary external length of 1.750 inches and an exemplary overall thickness of 0.25 inches. As shown in  FIG. 4 , slat  32  has an inner cavity  44  in which stuffing  42  is contained. Inner cavity  44  has an exemplary length of 1.5 inches and thickness of 0.1875 inches. Thus, the thickness of shell  40  along the top thereof (as depicted in  FIG. 4 ) is 0.0625 inches.  
         [0030]     Stuffing  42  is preferably made of an appropriate intumescent material. This material expands when heated above a known temperature in one direction if the other directions are confined. A relatively large expansion force and impulse may be provided, depending upon the rate of expansion, which quickly and effectively seals the spaces between (and/or around) the slats. The distance of the expansion depends upon the material and the thickness of the material, as well as the shell material.  
         [0031]     Making reference again to  FIG. 2 , when louver panel  16  is subjected to heat, the intumescent material will expand and contact the adjacent slat, thereby forming an airtight seal. The spacing between slats and the type and thickness of the intumescent material are all selected to properly provide this seal. The top slat in panel  16  is sealed with upper board  24  and thus all of the expansions between slats occur in a downward direction. This is merely one example, however, the expansion may occur upwards, or both upwards and downwards, or in any other direction necessary to form a seal.  
         [0032]      FIG. 5  depicts an aspect of an opening  34  in an end board  30  into which one or more louvers  32  may be seated. The end board  30  may be configured to allow the louvers  32  to move at an operator=s request, or when subjected to forces caused by expansion of the intumescent material. The end board  30  may alternatively hold the louvers  32  at a rigid angle, thereby helping direct any expansion of the intumescent material into place for forming a seal.  FIG. 6  depicts an alternative aspect of a slat  50 . Slat  50  comprises an outer skin or layer  52 , which may be made of a shrinkwrap or other veneer wrapping material, as is well known in the industry. Inside are upper and lower (as depicted in the figure) layers  54  and  56 , made of HDF, or another structural material such as (as non-limiting examples) wood or MDF. In between layers  54  and  56  is a layer  58  of an intumescent material, such as described above.  
         [0033]     In addition, strips of the intumescent material can be inserted in other parts of the louver door, such as on its edges so as to seal the space between the door and the door frame. Similarly, intumescent material can be used in the frame work. In either case, the material can be attached by conventional methods, such as gluing strips of the material into a solid wooden piece or may be inserted into a veneer and wrapped by HDE or MDE as described above. The presently disclosed louvers may be used in a variety of environments, including (as non-limiting examples) gratings and ventilation ducts; wooden or steel single-leaf or multi-leaf doors, with or without glazing; sliding doors, rolling gates; sound-insulation doors, functioning in the event of a fire at the same time as a fire and smoke doors, for hospitals, schools, hotels, and office buildings; doors with high mechanical stability for industrial construction; enhanced heat-insulating sliding doors for cold-storage rooms; elevator doors; doors on ships; and steel closures for fuel oil or other combustible material storerooms.  
         [0034]     The presently disclosed apparatuses, systems, and methods may be used with many different types of louver door configurations, including (as non-limiting examples): the single flat slat type; the inverted “V” type; and the type that has slats going in one direction on one door side, a central opening, and slats slanting in the other direction on the other door side. The present disclosure may be used with fixed slats or with slats of the adjustable or jalousie type. Portions of the louvers may be made from wood, metal, such as iron, steel, or aluminum, or plastic, such as those to which Ohanesian U.S. Pat. No. 5,778,598, is drawn, for example, which depicts a jalousie shutter door assembly assembled primarily from extruded plastic components.  
         [0035]     The previous description of some aspects is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these aspects will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other aspects without departing from the spirit or scope of the invention. For example, one or more elements can be rearranged and/or combined, or additional elements may be added. Thus, the present invention is not intended to be limited to the aspects shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.