Abstract:
The present invention describes an air quality containment unit for isolating a construction, renovation or maintenance project. The air quality containment unit contains dust, molds and other air-borne pollutants using a filter, such as a high-efficiency particulate air (HEPA) filter, to maintain a negative air pressure in the unit. The air quality containment unit includes at least one sealable orifice that allows workers to introduce, for example, an electrical cord into the unit without breaching containment.

Description:
[0001]    The present invention is a National Phase application of PCT/US2007/079605 and claims priority to U.S. application No. 60/850,705 filed 10 Oct. 2006. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The invention relates to a portable enclosure that contains potentially harmful substances during constructions or renovations. 
       BACKGROUND OF THE INVENTION 
       [0003]    Enclosures and partitions, collectively enclosures, are often used to separate portions of a building or room during construction, renovation or maintenance projects. An enclosure serves as a barrier to dust, noise, light, odors, molds, mildews, etc. An enclosure separates the work area from areas that need to remain clean. For example, an enclosure can protect immuno-suppressed patients in a hospital from exposure to potentially harmful molds and bacteria that are released during building repair or maintenance. More simply, an enclosure can prevent construction debris and dust from entering a living space. 
         [0004]    A simple enclosure includes a sheet of plastic or cloth that is nailed, screwed, stapled, taped or otherwise affixed floors, ceilings, and abutting walls. Alternatively, prior art teaches a spring-loaded jack system that secures the sheet in place without damage to floors, walls or ceilings. These simple enclosures can contain large particles during projects but, because of relatively large openings do little for very small particles, such as molds. 
         [0005]    Large openings can permit the release into the air during and after a project of potentially dangerous amounts of airborne particulates, mold spores, bio-aerosols, gas phase pollutants and odors. By way of example, molds and fungi are often present in dark, humid areas, such as ceiling tiles, ventilation ducts or pipes, and can cause diseases such as aspergillosis. Aspergillosis includes allergic bronchopulmonary aspergillosis, pulmonary aspergilloma and invasive aspergillosis. Colonization of the respiratory tract is also common. People in a suppressed immunologic state are particularly susceptible. In such people, aspergillosis can result in death. 
         [0006]    The Center for Disease Control and Prevention in Atlanta, Ga., USA has recognized that hospital construction and renovation projects pose particular risk to immuno-compromised patients, who may inhale airborne pollutants. Hospitals and other health care facilities have begun using portable enclosures that isolate construction, renovation and maintenance areas from patients. These units often include collapsible frames that support physical barriers. The enclosure should extend from the floor to the underside of the floor above. The unit should include gasketed doors with self-closing latching hardware and dampened walk-off mats both inside and outside of the construction area. The enclosure preferably includes a filter. The filter may include a high-efficiency particulate air (HEPA) filter maintains a negative air pressure in the enclosure relative to the rest of the area and simultaneously scrubs the air of contaminants. Alarms should signal any loss of negative pressure in the enclosure. In this manner, airborne hazards can be isolated from patients. 
         [0007]    Present commercial enclosures include rigid enclosures and collapsible enclosures, and comprise one or more plastic sheets stretched around a frame. The sheets often comprise woven polyolefin. The frame may include plastic or metal tubing. Prior art frames can be difficult to disassemble or collapse, and workers often are reluctant to disassemble the enclosure once installed. Wheels may be provided to move the enclosure, whether assembled or collapsed, from place to place. The filter may be placed inside or outside the enclosure. Because the floor of the enclosure is typically no more than about 3×5 feet, placing the unit in the enclosure limits the usable space for the workers. Despite the desire to contain the air-borne particulates, present enclosures require workers to penetrate the physical barrier provided by the enclosure for electric cords, cables or other required facilities. Such penetrations typically by-pass the security measures manufactured into the enclosure. The penetrations permit contaminants to escape from the enclosure and so compromise patient health and safety. 
         [0008]    A need exists for a portable enclosure suitable for hospital use that is easily collapsible and substantially completely isolates patients from construction, renovation or maintenance projects. 
       SUMMARY OF THE INVENTION 
       [0009]    The present invention describes an enclosure for use as an air quality containment unit. The enclosure is useful as a temporary enclosure for construction, renovation and maintenance projects. The enclosure includes walls comprising one or more sheets stretched around a frame, a filter such as a high-efficiency particulate air (HEPA) filter for maintaining a negative air pressure in the unit, and at least one sealable orifice integrated with the wall. Optionally, the enclosure includes at least one electrical outlet accessible by a worker inside the enclosure. 
         [0010]    The sealable orifice substantially prevents air from flowing into or out of the unit, but permits objects to pass through the sealable orifice. The sealable orifice includes a deformable gasket defining an opening. The gasket may comprise an elastomer, a closed-cell foam, or a gel pack. The opening may be defined, for example, by a plurality of elastomeric baffles, a plurality of gel packs circumscribed around the opening, or a throughbore. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]      FIG. 1  shows a front view an enclosure of the present invention. 
           [0012]      FIG. 2  is a rear view of the enclosure of  FIG. 1 . 
           [0013]      FIG. 3  is a perspective view of the enclosure of  FIG. 1 . 
           [0014]      FIG. 4  is a top view of the enclosure of  FIG. 1 . 
           [0015]      FIG. 5  is an exploded view of a sealable orifice of the present invention. 
           [0016]      FIG. 6  is a perspective view of the sealable orifice of  FIG. 5 . 
           [0017]      FIG. 7  is a sectional view of the sealable orifice of  FIG. 5 . 
           [0018]      FIG. 8  shows flanges for an alternative embodiment. 
           [0019]      FIG. 9  is a sectional view of another alternative embodiment. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0020]    The enclosure includes air quality containment unit including a plurality of walls formed by a frame supporting at least one sheet or film. The frame and sheet define a space having a plurality of side walls and, optionally a top wall and a bottom wall. The enclosure should contain air borne particulates that are generated during construction, renovation or maintenance projects. To this end, the sheet comprises a material that is substantially impervious to air-borne particulates, such as dust or mold. The material may be, for example, an extruded or woven plastic such as polyvinylchloride or a spun polyolefin. The space should be large enough that a worker can perform the necessary operations within the enclosure. Practically, this means the space will have a floor that is usually at least about 60×100 cm and preferably at least about 100×150 cm. The height of the space should be at least sufficiently tall for a worker to kneel. One skilled in the art would appreciate that the actual size of the enclosure can vary. 
         [0021]    One embodiment of the present invention is shown in  FIG. 1 .  FIG. 1  shows a front view of the air quality containment unit  1 . The unit  1  has a front wall  2  having a front width  5 . The front wall comprises an entrance flap  3  and a front panel  4 . The entrance flap  3  is capable of sealing engagement with the front panel  4 . Sealing engagement is facilitated by a sealing fastener  7 . The sealing fastener  7  may be continuous such as, for example, a zipper or Velcro® strips. Disengaging the entrance flap  3  from the front panel  4  defines an opening that is sufficiently large for a worker and his tools to enter and exit. Conveniently, the entrance flap  3  may have a window  6  integrated into the entrance flap. The window will typically comprise a clear vinyl. 
         [0022]      FIG. 2  shows a back wall  21  having a back width  27 , and comprising an electrical channel  22 , a sealable orifice  23 , and filter  24 . The back width  27  is often the same dimensions as the front width  5 . Optionally, a pair of wheels  25  connected by an axle  26  facilitates portability by permitting the enclosure to be tipped and rolled to a new location. The unit  1  may also have at least one handle, not shown, that facilitates tipping the unit  1  onto the wheels  25 . The electrical channel  22  provides electrical power to the enclosure space without breaching containment. The electrical channel  22  includes at least one electrical outlet in the enclosure space that is electrically connected to an electrical plug on the outside of the space. The electrical channel  22  is sealed to prevent the escape of contaminants from the enclosure. Sealing may occur by any means including, for example, a gasket, sealant, welding, laminating, or molding in place. Connecting a source of electricity to the plug supplies electrical power to the outlet. The electrical outlet preferably comprises a power strip having a plurality of outlets. 
         [0023]    The sealable orifice  23  permits a worker to pass any suitably sized object through the sealable orifice  23  without substantially breaking containment. The object could be temporarily passed through the sealable orifice  23  or placed there for the duration of the project. Prior art required a worker to unseal the entrance flap or pass the object above or below the enclosure. Prior art had even forced workers to cut the enclosure walls for electrical cords, air compressor cables, etc. Alternatively, workers had lifted the base of the enclosure from the floor. Either solution breached containment of the enclosure. 
         [0024]    The sealable orifice  23  includes a gasket defining an opening. Of course, the enclosure may include a plurality of sealing orifices, and the sealing orifices may be distributed in the enclosure walls as needed. The opening can be of any convenient size. Absent any object, the gasket substantially prevents air from passing through the sealable orifice  23 . In the presence of an object, the gasket conforms to the exterior dimensions of the object thereby reducing air flow between the enclosure and the outside. Conveniently, a worker can pass a tool, cable, etc. through the sealable orifice  23  without opening the entrance flap. The gasket can be of any suitable design and may comprise an elastomer, closed-cell foam, gel pack, or combination thereof. Elastomer means any material capable of substantially elastic deformation with 100% strain. Elastomers include, for example, natural and synthetic rubbers and copolymers, silicones, and polyurethanes. Closed-cell foams are well-known in the art and comprise polymers such as, for example, polystyrene and substituted and non-substituted polyolefins including polyethylene, polypropylene, polyvinylchloride, and polytetraflouroethylene. Gel pack means any component comprising a deformable outer shell containing a fluid. Fluid means a gas or liquid, in particularly a liquid having a substantial viscous component, such as a gel or polymeric oil. Examples of a gel pack include vinyl shells containing a silicon oil, an aqueous solution, or polymeric gel. 
         [0025]      FIG. 3  shows a side view of a unit  1  having a height  37  and a length  38 , and comprising an X-shaped frame  31 . The frame  31  includes top spars  32  and bottom spars  33  joined at a hub  34 . The hub  34  permits the spars to rotate relatively to each other so that the frame  31  collapses. Preferably, the front wall  2  collapses towards the back wall  21  so that the enclosure may be easily tipped onto the wheels  25 . The hub  34  may include a ratcheting mechanism that permits the front wall  2  and back wall  21  to be fixedly separated at various dimensions. Optionally, the frame may include a top member  35  and bottom member  36  to rigidize the frame  31  and improve stability. The members  35 ,  36  may include a telescoping mechanism for collapsing and setting up the unit  1 . 
         [0026]      FIG. 4  shows a top view of the unit  1  including side spars  41 . Side spars  41  may be rigid but may also be telescoping. Telescoping side spars  41  permit changing the widths  5 ,  27  of the unit  1 . Telescoping side spars also permit greater portability of the enclosure. One skilled in the art would appreciate the mechanisms for including a telescoping feature into the side spars  41 . In this embodiment, a filter  24  is shown on the outside of the back wall  21  of the unit  1 . The filter may be connected to the enclosure via an air duct passing through an enclosure wall. Optionally, the filter  24  may be placed inside the enclosure  1 . Typically, the filter will be a HEPA filter. The filter will maintain a negative pressure in the air quality containment unit so that contaminated air does not escape the enclosure. If the filter is outside the enclosure, a sealable orifice may be fashioned to accommodate the air duct. Alternatively, an air duct connection may be fixed to an enclosure wall in the same manner as the electrical channel. 
         [0027]      FIGS. 5-7  show one embodiment of the sealable orifice  23 . The sealable orifice  23  comprises a pair of flanges  51 ,  52  sandwiching a deformable gasket  53 . The gasket defines an opening  54  that passes completely through the gasket  53 . The opening  54  is capable of substantially conforming to objects passing through the opening  54 . In operation, a wall  71  of the enclosure will define a hole  72  for receiving the gasket  53 . The flanges  51 ,  52  are placed on either side of the wall  71 . Fasteners  73  secure the flanges  51 ,  52  together through the wall  71  thereby securing the gasket  53  in the hole  72 . As shown, the fastener includes a bolt and nut. This embodiment permits replacement of a gasket  53 , which has deteriorated, and the flanges  51 ,  52  reinforce of the hole  72 . Alternatively, the gasket may be permanently fixed to the wall such as by welding or adhesive, such that the sealable orifice consists essentially of the gasket. 
         [0028]    An alternative fastener, as shown in  FIG. 8 , includes a twist-and-lock system. The system comprises a first flange  51  with a plurality of prongs  81  and a second flange  52  defining a plurality of keyhole openings  82 . The prongs  81  include a shaft  87  that enlarges at the tip  86 . The keyhole opening  82  includes a slot  83  and an aperture  84 . The aperture  84  is larger than the slot  83 . The prongs  81  of the first flange  51  align with the apertures  84  of the second flange  52  so that the tip  86  extends beyond the aperture  84 . Extending the tip  86  beyond the aperture  84  may require a compressive force. Twisting the flanges  51 ,  52  relative to each other locks the tip  86  against the second flange  52  through the slot  83 . Optionally, the prongs  81  may be reinforced to resist breakage during twisting. This fastener permits a sealable orifice to be installed or removed without tools. Conveniently, the prongs  81  may include a sharp tip  86  that can penetrate through the wall  71  by pressing the gasket  53  against the wall  71 . 
         [0029]    The gasket  53  may define an opening  54  of any convenient size. The size of the opening  54  will depend on its intended use and the elasticity of the gasket  53 . For example, where the intended use consists of feeding small cables through the opening and the gasket comprises a relatively soft material such as 1 kg (2.2 pounds) weight polystyrene closed-cell foam, the opening may be formed by one or more slits cut through the gasket. Larger opening may be formed by a plurality of gel packs circumscribing the hole. As shown in  FIG. 9 , the gasket  53  may even comprise a plurality of elastomeric baffles  91 . The baffles extend from a perimeter  92 . Each baffle  91  defines an opening  54 . The openings  54  permit passage of cords, tubing, wiring, and the like. The openings  54  of the baffles  91  may be in-line as shown or may be staggered to further restrict air ingress/egress. 
         [0030]    Obviously, numerous modifications and variations of the present invention are possible. It is, therefore, to be understood that within the scope of the following claims, the invention may be practiced otherwise than as specifically described. While this invention has been described with respect to certain preferred embodiments, different variations, modifications, and additions to the invention will become evident to persons of ordinary skill in the art. All such modifications, variations, and additions are intended to be encompassed within the scope of this patent, which is limited only by the claims appended hereto.