Abstract:
A passive brush seal effectively to limit conditioned air such as humidity, temperature or filtered air, or contaminated air such as smoke or fumes from an area of greater pressure to one of lower pressure. The passive brush seal is in the form of a strip brush with triangular filaments that provide an improved block to the flow of gases. The shape of the filaments is such that they inter-fit or interlock and separate less readily. Important applications are as elevator seals or clean room or computer room seals.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application is a continuation-in-part application of U.S. application Ser. No. 11/820,118, filed Jun. 18, 2007. 
     
    
     DISCLOSURE  
       [0002]    This invention relates generally as indicated to an environmental brush seal, and more particularly to a strip brush passive seal or barrier shield for protecting or isolating environments such as elevator shafts, clean rooms, computer rooms, or other gaps or closures where pressure differentials may exist. 
       BACKGROUND OF THE INVENTION 
       [0003]    Air infiltration is a problem in most buildings. Not only is it costly, but for the people who live or work in a drafty environment it can be uncomfortable as well. The problem with air infiltration is that in the summer heat enters a building through small gaps around openings. Of course, air conditioned air escapes from these same openings. In the winter, this problem is compounded by a phenomenom known as “chimney” or “stack” effect. Essentially, hot air rises and escapes through openings near the top of the structure while cold air is drawn in through gaps near the bottom of the building. The chimney effect can cause air movement for example, as high as 10 m.p.h. Every cubic foot of infiltrated air will be heated or cooled at a cost. Over the course of a year, the additional energy costs are significant. 
         [0004]    Brush weatherseals have a significant environmental and energy impact and allow significantly less air leakage than vinyl seals. For instance by adding brush weatherseals around a 10′×10′ sectional door, over a six-month heating season the brush seals will keep out an additional five million cubic feet of air, which will not require heating or cooling. With high winds on large doors such as airport hangars, brush weatherseals or have a real impact. A brush weatherseal generally pays for itself in savings in about a year, and with a life expectancy of at least 10 years, brush seals afford a considerable return over time. 
         [0005]    Strip brushes have long been used as passive environmental seals for shielding and closing gaps. Applications include paint and powder booths, dark rooms, clean rooms, computer rooms, cable management, wiring and lever seals, as well as a wide variety of door seals. Other applications include garage doors, elevator doors or any gap seal such as the sides of moving escalators or walkways. An example of such brush seals are those made and sold by SEALEZE®, a unit of Jason Incorporated, of Richmond, Va. 
         [0006]    Strip brushes are normally formed by folding a layer of filaments about a wire core that is clinched by a channel folded about the bight portion of the filaments and the core. Typically the filaments are circular in section, and metal or plastic such as nylon, and the core and channel may be plastic or metal. Other strip brush constructions may also be used, such as melting or gluing or stapling one end of the filament into a retaining strip material. 
       SUMMARY OF THE INVENTION 
       [0007]    It has been discovered that a more effective environmental seal is obtained if the filaments are triangular in transverse section, and of such a shape that the filaments when not separated will nest with each other to form a barrier or wall without significant pockets or separations. The relatively sharp acute angle corners of the filaments, which inter-fit or interlock, require greater pressures to force the filaments apart. More rounded less sharp corners are more easily forced apart or twisted past one another to create openings or gaps for smoke or gases to pass through. Substantially isosceles or equilateral triangular filaments form a tighter barrier. They substantially reduce gas flow in use when compared to conventional filaments. 
         [0008]    The acute angled corners of the filaments are more effective than the typical cylindrical or round filament since the angled corners tend to create turbulence in the form of eddies or vortices as air tries to move past the filaments from an area of higher pressure to that of lower pressure reducing the force on the filaments. 
         [0009]    The improved environmental seal or shield has many applications. One of the applications is as a smoke seal in elevator shafts. Elevator shafts in buildings often experience phenomena called stack effect, which is the induction of airflow caused by a difference in temperature between the air inside and the air outside of the building. When the air outside is colder than the inside air, airflow is induced upward. When the air is warmer outside of the building than inside, airflow is induced downward into the building. In the event of a fire within the building, or the generation of toxic or noxious gases, smoke and gases can be pulled into elevator shafts and transported via the shaft to other floors of the building. Openings in closed elevator doors can permit these gases and smoke to leak beyond the confines of the elevator shaft and into lobby areas on otherwise unaffected floors. 
         [0010]    To reduce or eliminate the passing of these gasses and smoke through the openings of these closed elevator doors, several devices have been designed to restrict the openings in these doors. Examples of these devices include assemblies disclosed in U.S. Pat. No. 5,383,510 issued Jan. 24, 1995, U.S. Pat. No. 5,195,594 issued Mar. 23, 1993, and U.S. Pat. No. 5,836,424 issue dated Nov. 17, 1998. 
         [0011]    Computer rooms and other rooms which are environmentally controlled for manufacturing processes often have passages through the floors or walls to provide access for cables, or in walls between rooms for the passage of utilities or materials between rooms. These openings often permit undesired flow of air (smoke, fumes, dust, etc.) between those rooms and cause unwanted contamination, or higher load air cleaning or conditioning requirements. The triangular filaments used in the device provide easy passage of materials or cables through the filaments, and yet their triangular shape provides greater resistance to undesired air flow than the commonly used round filaments. 
         [0012]    To the accomplishment of the foregoing and related ends the invention, then, comprises the features hereinafter fully described and particularly pointed out in the claims, the following description and the annexed drawings setting forth in detail certain illustrative embodiments of the invention, these being indicative, however, of but a few of the various ways in which the principles of the invention may be employed. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]      FIG. 1  is an illustration of an environmental brush seal of the present invention mounted on an elevator door-in-sill configuration; 
           [0014]      FIG. 2  is a similar illustration with a sill guide in a sill configuration; 
           [0015]      FIG. 3  is a similar illustration of the brush seal in a double door with a sill guide in a sill configuration; 
           [0016]      FIG. 4  is an illustration of the brush seal at a sliding door and doorway header configuration; 
           [0017]      FIG. 5  shows the brush seal applied to the elevator sliding door and doorjamb or side-of-door configuration; 
           [0018]      FIG. 6  illustrates the application to a typical elevator double door seal gap; 
           [0019]      FIG. 7  shows a bottom door seal on a typical swing door; 
           [0020]      FIG. 8  illustrates the brush seals facing each other in a mail delivery letter-slot frame; 
           [0021]      FIG. 9  illustrates the brush seals in a similar frame acting as a grommet for wiring or utilities into a computer or clean room; 
           [0022]      FIG. 10  illustrates one construction of the invention; 
           [0023]      FIG. 11  is an enlarged sectional illustration of a strip brush according to the invention made by another method. 
           [0024]      FIG. 12  is a transverse enlarged section of a filament of triangular configuration; 
           [0025]      FIG. 13  is a transverse section through a group of such triangular filaments slightly separated; 
           [0026]      FIG. 14  is a section through a group of such filaments showing how they nest to form a wall; 
           [0027]      FIG. 15  is a schematic illustration somewhat enlarged showing the vortices or eddies created by the sharp corners upon flow of smoke or gases therepast; and 
           [0028]      FIG. 16  is a chart illustrating the results of tests made to compare the effectiveness of standard SEALEZE® brush seals with those of the present invention having triangular filaments. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0029]    Referring first to  FIG. 1  there is illustrated an elevator door at  20  which projects into a slot  21  in header  22  and also rides in slot  23  in sill  24 . The door slides toward and away from the viewer within the header and sill slots. The door is of course shown broken away foreshortening its vertical height. The typical roller-track structure and actuator are not shown. 
         [0030]    In  FIG. 1 , two environmental seals in accordance with the invention are shown, one at  26  within the header slot  21 , and the other at  27  within the sill slot  23 . The seals are in the form of strip brushes hereinafter described which slide into the channels of aluminum extruded holders shown at  28  and  29 , respectively, held to the structures by fasteners shown at  30  which extend through elongated slots  31  permitting the holder to be adjusted toward and away from the moving door. It is noted that the assembly of  FIG. 1  shows two different types of holders. At the top the holder has an angled flange  33  extending from the inside corner of the channel  34  while the sill seal  27  holder  29  has a straight flange  35  extending from the inside corner of the channel  36 . The strip brush seals engage the entire top of the door within the slot  21  and the entire front of the door below the sill sealing the hallway or foyer on the left from the shaft on the right when the door is closed. 
         [0031]    Referring now to  FIG. 2  an elevator door  38  is provided with a bottom sill guide  40  fastened to the interior corner of the door by fasteners  41  extending through upwardly extending flange  42 . The sill guide extends beneath the door as shown at  43  and terminates in a downwardly extending flange  44  riding in slot  45  in sill  46 . 
         [0032]    The environmental seal strip brush  48  mounted in straight flange holder  49  is fastened to the door adjacent the guide  40  as shown and rides against the sill as the door moves. 
         [0033]    In  FIG. 3 , one door  52  of a double door—sill guide configuration is shown. The door includes a sill guide  53  which includes an upper flange  54  fastened to the door  52 , a horizontal projection  55 , and a downwardly extending flange  56  riding in slot  57  in sill  58 . The other slot  59  is for the second door, not shown. In this configuration two environmental seal assemblies are employed, shown at  61  and  62  adjacent to and on each side of the sill guide  53 . 
         [0034]    In  FIG. 4  the sliding door  64  is sealed at its top  65  by environmental seal assembly  66  fastened to wall panel  67  in turn mounted on header  68 . The seal assembly includes the angled flange holder  69  fastened to the wall panel. The door moves toward and away from the viewer as in  FIG. 1 . 
         [0035]    In  FIG. 5  there is a typical sliding door and doorjamb configuration. In this figure the door  71  moves parallel to the plane of the figure while the jamb  72  at the side of the door is fixed. An environmental seal assembly shown at  73  is mounted on the end  74  of the door  71 . In the  FIG. 5  position the door is closed and the adjusted projecting edge of the seal assembly engages the face  75  of the jamb creating the seal at the side of the door. 
         [0036]    In  FIG. 6  there is illustrated a typical elevator double door seal at the gap between the sliding doors  77  and  78 . The end or edge  79  of the door  77  has mounted thereon the environmental seal assembly  80  in the same manner as in  FIG. 5 . The projecting edge of the seal assembly rides however against the face  81  of the door  78 . While the seal of  FIG. 5  closes the gap between the sliding door and jamb, the seal of  FIG. 6  closes the gap between the two sliding doors. 
         [0037]    In  FIG. 7  there is illustrated a different type of door  83 , which may be a variety of types, such as a hinged swinging door or an overhead garage door. Mounted on the lower edge of the face  84  is an environmental seal assembly  85  closing the gap  86  between the bottom of the door and the floor  88 . With a swinging door the projecting edge of the seal assembly will ride or sweep against the floor. With an overhead door the seal will close the gap only when the door is closed.  FIG. 7  more clearly shows the fastener  89  and slot  90  in the holder enabling the sill to be adjusted to close the gap existing when the door is closed. 
         [0038]    The improved environmental seal of the present invention also has application as astragal seals and two such examples are seen in  FIGS. 8 and 9 . Astragal seals are those where the projecting edges of the seals just touch, abut or confront each other, such as closing the gap between two doors. 
         [0039]      FIG. 8  illustrates what would normally be called a mail slot assembly shown generally at  92 . A typical application would be on a door  93 . The strip brush seals shown at  94  and  95  are mounted in a rectangular frame  96  secured around a slot in the door (not shown) by fasteners  97 . The frame forms an open slot  98  and an optional angled roof or shield  99  projects from the top of the slot. The filaments of the two facing brush strip seals just touch each other at  101 . This permits items such as mail to be pushed through the slot without exposing the interior to the wind or weather on the exterior. 
         [0040]    A similar assembly is shown in  FIG. 9 . The environmental seals  103  and  104  are mounted in elongated rectangular frame  105  mounted over a slot or opening in surface  106 . The tips of the seals just touch or abut each other at the line  107 . The applications of the assembly are many and varied. For example the surface  106  may be the wall, floor, ceiling or a column surface in a clean room or computer room where the interior air is cleansed and conditioned, and normally at a higher pressure than the outside air. The seal assembly then permits the introduction into the room through the seal assembly of utilities such as the illustrated wiring  108 . Piping or tubing may equally well project through the seal assembly without compromising the interior of the room. 
         [0041]    Another use for the assembly of  FIG. 9  would be as a gearbox or housing cover and the projecting item would become a gearshift handle or operating lever. The assembly permits the handle to move along the line  107  while protecting the interior of the box from dirt or debris (and the exterior from grease). 
         [0042]      FIG. 10  illustrates one form of strip brush seal in accordance with the invention, and also illustrates the components of one method of seal assembly construction. 
         [0043]    The triangular filaments are shown at  110  and they are formed as a layer folded about wire core  111  and clenched at the fold by channel  112 . The channel is provided with slightly flared edges seen at  113  which serves several purposes. It avoids biting into the filaments with a sharp edge and the flare or projection of the edges provides support when the strip brush is inserted into channel  115  of holder  116 . The channel  115  has short interned flanges or edges  117  that fit beneath or against the flared edges  113 , keeping the brush strip in the channel when telescoped in from the end. The holder is of the straight flange type with mounting flange  118  projecting from the corner of the channel. The face  120  of the folded layered filament bundle is trimmed to the desired length and face. 
         [0044]    Strip brushes may also be made as shown in  FIG. 11  by forming a flat continuous stack of triangular filaments  122  stacked to form the wall or barrier, and while held one edge may be heated to form a bead  123  which is thermally welded to a plastic backing  124  and then cooled to become permanently combined. The bead and backing may be shaped to fit or slide within a channel of a frame member. 
         [0045]    Referring now to  FIGS. 12-15  there is illustrated a triangular form of filament shown at  145  that has three sharp corners  146 . The edges or corners impede the filaments from moving past each other. As seen in  FIG. 13  the filaments slightly separate as indicated at  147  upon air pressure on one side of the seal as seen at  148 . As seen in  FIG. 14  the filaments nest to form a wall or barrier  128  with little or no interstitial spacing to permit penetration of smoke or gases. Of course the typical filament bundle will contain many more than the three layers illustrated. As seen in  FIG. 15  the sharp edges seen for example at  150  and  151  create areas of reduced pressure and reduced velocity, as shown by the turbulence seen at  153  and  154  in the form of eddies or vortices. This diminishes the ability of the smoke or flowing gases not only to penetrate the seal, but also to spread the filaments apart. 
         [0046]    Each of the corners of the triangular filament is a relatively sharp acute angle and the triangle is an isosceles triangle though not necessarily an equilateral triangle. The triangular shape of the filament is of at least two acute angle corners even if a right triangle. Those illustrated have three acute angle relatively sharp corners. 
         [0047]    As the filaments  147  inter-fit or intermesh and their shape impedes the filaments from moving past each other in response to the pressure or flow of smoke or gases as indicated by the arrows  148 . The triangular filaments nest or inter-fit with little or no interstitial spacing to form a wall or barrier and the sharper edges and create areas of reduced pressure and velocity, as indicated by the eddies or vortices  153  and  154  further diminishing the ability of smoke or gases to penetrate or spread the filaments apart. 
         [0048]    This of course is in contrast to circular filaments or filaments with more rounded shapes that have little resistance to movement past each other, and separation. 
         [0049]    The angled corner transverse configuration of the filaments also makes the filaments somewhat stiffer than circular filaments and accordingly less apt to splay or separate from pressure on one side. This coupled with the angular inter-fitting or locking of the filaments makes for an effective environmental seal. But even if they do separate or splay the corners still further hinder the transfer of gases from one side to the other making a more effective environmental seal. 
         [0050]    As a filament material a non-abrasive plastic is preferred such as nylon 6 or polypropylene. 
         [0051]    Tests demonstrate that up to a 25% better seal can be obtained with brush seals of the invention when compared with brush seals using ordinary round filaments. 
         [0052]      FIG. 16  illustrates the results of tests made to compare the effectiveness of Standard SEALEZE® brush seals with round filaments with those of the present invention having triangular filaments. As can be seen from  FIG. 16  the triangular filament brush seals of the present invention produced significant improvements. 
         [0053]    It can now be seen that there is provided a more effective energy saving environmental seal for many applications. 
         [0054]    Although the invention has been shown and described with respect to certain preferred embodiments, it is obvious that equivalent alternations and modifications will occur to others skilled in the art upon the reading and understanding of this specification. The present invention includes all such equivalent alterations and modifications, and is limited only by the scope of the claims.