Abstract:
A portable HEPA filter chamber is provided with a pair of wheels and a handle whereby it can be moved by a person in the manner of a two-wheeled hand-truck. One or more inlet openings receive air from an area to be cleaned, dried, or decontaminated. An air outlet is adaptable to the air inlet height of standard, widely-used carpet dryer blowers. Pre-filters are provided in the portable chamber upstream of the HEPA filter. Strapping holds the blower unit to the outlet of the filter chamber. Support wheels and a handle enable convenient hand-truck type operation to facilitate movement of the combination when and as needed in the area being dried. An upstanding perimeter flange, and the handle, when retracted, serve as a fence to stabilize multiple chambers, when stacked for storage or transportation in a truck. The exterior wall of the chamber is shaped for inter-fitting with others to minimize floor space for storage and transporting. Hook-on adjustable air flow inlet valves are usable for mold remediation operations.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    This invention relates generally to structural drying work such as, for example, the drying of flooded areas of houses, offices, and other spaces.  
         BRIEF DESCRIPTION OF PRIOR ART  
         [0002]    For restoration of interior spaces which have been flooded, widely used procedures include portable dehumidifiers and portable carpet-dryer blowers. These machines are powered by electric motors which can be plugged into readily available electric outlets in the structure. For many years, contractors in the field of building demolition have been concerned about dust in general, particularly asbestos. Similarly, contractors in the field of flood damage control and remediation, have been concerned with drying areas and the contents therein. These contractors and workers in healthcare fields and in the insurance industry have been particularly concerned with addressing mold problems.  
           [0003]    In the course of flood damage control and remediation activity, there has been increasing usage of high efficiency particulate air (HEPA) filters. Several systems suggesting the use of such filters have been made the subject of U.S. patents. Those known to me include a U.S. Pat. No. 5,417,729 to Greenleaf and which discloses a portable blower unit with a separable HEPA filter assembly and removable pre-filter. U.S. Pat. No. 4,968,333 to Ellis et al. discloses a portable primary filter unit and a portable blower and final filter unit containing HEPA filter units. U.S. Pat. No. 4,838,910 to Stollenwerk et al. discloses a portable blower unit with a separate HEPA filter unit. The Natale U.S. Pat. No. 4,613,348 discloses a HEPA filter-containing canister with a vacuum motor assembly mounted to the top of the canister, or a separate vacuum cleaner device with a suction hose connected to the canister. Other patented devices which have been brought to my attention are known and will be identified in an Information Disclosure Statement to be filed with or following the filing of this application. It is an object of my invention to provide a HEPA filter system that can be conveniently and effectively used by those working in the field of structural interior drying and/or mold remediation work.  
         SUMMARY OF THE INVENTION  
         [0004]    Described briefly, according to a typical embodiment of the present invention, a portable HEPA filter chamber is provided with wheels and a handle whereby it can be moved easily by a person from place-to-place in the way that a two-wheeled hand-truck can be moved. It includes one or more inlet openings for entry of air from an area to be cleaned, dried, or decontaminated. It has an air outlet adapted to connection to a standard, widely used carpet-dryer blower. Pre-filtering is provided in the portable chamber, upstream of the HEPA filter. Means are provided to conveniently anchor and seal the air intake of a separate and conventional carpet-dryer blower to the air outlet of the filter chamber. Means are provided to conveniently adapt the chamber outlet to different size blower inlets. Means are also provided on the chamber to facilitate convenient stacking and storing multiple chambers, when not in use. Means are provided on the chamber inlets to enable the user to easily attach a hose to an inlet, or to connect an inlet to a mold containment room without the use of a hose. Means are provided to adjust air flow into the chamber if, and as, desired.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0005]    [0005]FIG. 1 is a side elevational view of the HEPA filtration chamber connected to a conventional carpet-dryer blower, the latter being shown in broken lines.  
         [0006]    [0006]FIG. 2 is a top plan view of the combination.  
         [0007]    [0007]FIG. 3 is a front view thereof.  
         [0008]    [0008]FIG. 4 is a fragmentary front view, but omitting the showing of the blower, to better show the height adjustment capability of the outlet snout.  
         [0009]    [0009]FIG. 5 is a rear elevational view of the chamber without the blower.  
         [0010]    [0010]FIG. 6A is a front view of the adjustable air flow ring valve assembly for mounting to the inlet openings on the back of the chamber.  
         [0011]    [0011]FIG. 6B is a section through the ring assembly taken at line  6 B- 6 B in FIG. 6A and viewed in the direction of the arrows.  
         [0012]    [0012]FIG. 7A is a front view of the outlet cap assembly.  
         [0013]    [0013]FIG. 7B is a section through the cap assembly taken at line  7 B- 7 B in FIG. 7A and viewed in the direction of the arrows.  
         [0014]    [0014]FIG. 8 is a top view of a group of three units demonstrating the interfitting feature of the side walls for storage.  
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0015]    For the purposes of promoting an understanding of the principles of the invention, reference will now be made to the embodiment illustrated in the drawings, and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended, such alterations and further modifications in the illustrated device, and such further applications of the principles of the invention as illustrated therein being contemplated as would normally occur to one skilled in the art to which the invention relates.  
         [0016]    Referring now to FIG. 1, the illustrated filter chamber  11  includes a box fabricated preferably from stainless steel. It has two wheels  12  at the lower back corners, and a support leg  13  at the center of the front. It might be found preferable to have two support legs, one at each comer of the front. The leg and wheels have non-marring bottom and resilient tread material, respectively. As shown in the top plan view of FIG. 2, the side walls  14  are notched at  14 N, providing offset rear side wall portions  14 R and front side wall portions  14 F. The notch  14 N is half-way between the front wall  16  and rear wall  17 . This construction enables the units to be placed side-by-side in interfitting relationship, by alternate units facing in opposite directions as shown in FIG. 8 for units  17 A,  17 B and  17 C. This can be advantageous in a warehouse, a van, a “high cube” truck, or other vehicle, during storage or transportation, by minimizing the overall floor space requirement for storage of these chambers while not in use.  
         [0017]    The chamber has a top  18  (FIGS. 2 and 5) and which is indicated by the dotted line in FIGS. 1 and 3 below the top edge  19  of the side and front walls. Therefore, there is an upstanding flange  21  around the sides and front of the chamber. This defines a “footprint” of fencing around an area that would be occupied by the leg  13  and wheels  12  of another identical chamber. As such, it enables the chambers to be stacked vertically, three units high, when not in use, to further conserve horizontal space in a warehouse, shop, or van-type vehicle.  
         [0018]    A handle  22  is provided immediately inside the rear wall  17  and has horizontal bight portion  22 G and downturned arms  22 L received in tubes (not shown) formed on the inside of the rear wall portions  17 S near the side wall portions  14 R. Each of these arms has holes in the rear and receiving lock pins  23  that are secured by lanyards  23 A, whereby the handle can be pulled upward from the recessed position shown by the solid lines in the figures, to the extended position shown by the broken lines in FIG. 3. When locked in the extended position, the handle is useful for moving the chamber across a floor in the manner of use of a conventional two-wheeled hand truck, by tipping it upward about the wheels and pushing or pulling it with hands gripping the bight portion  22 G of the handle. As shown best in FIGS. 1 and 2, the upper portions of the handle arms are angled rearwardly at  22 A. This feature enables the wheels  12  of another like chamber to neatly fit and be retained in place when the other chamber is stacked on the one chamber. In the above mentioned two-legged alternate embodiment, the legs can be in canted orientation to fit in the front comers of the canted portion  21 F of the flange at the top front on each side of the chamber.  
         [0019]    The front wall  16  of the chamber has a circular opening  16 H therein receiving a snout  26  which is a fabricated unit including a cylinder  27  with a radially extending flange  28  welded to it and abutting the front wall  16 . The cylinder  27  extends from flange  28  through the chamber front wall opening  16 H to an inner (relative to the chamber) edge  29  of the cylinder inside the chamber. The cylinder  27  extends from flange  28  outward from the chamber to an outer edge  30 . A bulb-type seal  31  is mounted and fixed to the outer edge of the snout cylinder  27 . Typically the diameter of the snout cylinder is 10 inches.  
         [0020]    A conventional carpet dryer blower assembly  32  is shown by the broken lines. It has a motor cooling inlet opening at  33  and air mover inlet opening  34  and discharge opening  36 . This dryer is strapped to the outlet opening snout  26  of the filter chamber by a strap  37 . In order for the blower to pull air only through the filter chamber, and not discharge unfiltered air from the blower outlet  36 , the motor air inlet  33  is closed by a block-off plate and seal assembly  38  (FIGS.  1 - 3  and  7 A and  7 B). This plate has two loops  39  receiving the strap  37  through them. The lower end of the strap is anchored to the bottom front of the chamber at  39 , being sandwiched between the bottom  46  of the chamber and the top of leg  13  which is bolted to the bottom  46  of the chamber. The strap is passed from this anchorage forward under the blower and up through the loops  39  in the block-off plate and up through a loop  41  on the chamber front wall  16 , and back upon itself at  42 , where it is snugged and anchored as by a clamp or, preferably, a hook-and-loop fastening system such as known by the brand name Velcro.  
         [0021]    For passageway adaptation to different heights of inlet openings  34  of different brands of carpet dryer blowers, the snout assembly  26  can be moved up and down to a limited extent. In an example for the ten inch diameter snout, the front opening  16 H in the wall  16  is large enough for vertical movement of the snout a total of 1.5 inches (dimension A in FIG. 4). This is accommodated by vertical slots in the front panel which receive two screws such as  44  received in two elastic lock nuts inside the wall and by which the flange  28  is secured to the front wall  16 . FIG. 4 illustrates a total range of positions of the snout, the right-hand side of the illustration being the upper limit of the range, and the left-hand side of the illustration representing the lower limit. Of course, other ranges can be provided for by longer slots in either the front wall  16  or in the flange  28 .  
         [0022]    Referring now to FIGS.  5  and following, the back of the chamber comprises a central panel  17 C which is readily removable, being confined at the sides by stiles  17 S and at the top and bottom by rails  17 T at the top and  17 B at the bottom. The rail  17 T at the top is a down-turned flange from the top panel  18 . The rail  17 B at the bottom is an upturned flange from the bottom panel  46  of the chamber. Panel  17 C can be removed from the chamber by simply lifting it slightly, pulling the bottom edge out from confinement by the bottom rail  17 B, and lowering it and pulling the panel out from the confinement by the top rail  17 T. Upon removal of the back panel  17 C, there is immediate and easy access to the filters. These may include a first pre-filter  47 , a second two-stage carbon/poly pre-filter  48 , a third two-stage activated carbon pre-filter  48 A, and a rack containing the 99.97% HEPA filter  49 . This arrangement can be most readily seen by viewing the breakout portion of the side wall of the chamber as shown in FIG. 1. The first pre-filter can easily be seen through the side breakout in FIG. 1 and through the two openings  17 U and  17 L in the removable panel  17 C in FIG. 5. When the chamber is used in a room in a normal air scrubbing and drying application, these openings  17 U and  17 L may be exposed directly to the room environment. But for some applications, the present invention is quite useful for removing air and contaminants for a mold containment room. For example, if there is an area in a structure and which has been highly contaminated with mold, it is a typical practice to isolate the area where the mold is evident, by building a “containment room” of polyethylene film on some kind of framework. An opening is provided in a wall of the containment room to expose the area of mold to the interior of the containment room, having already taped all the way around the area to avoid any escape into the rest of the larger room in which the containment room is built. Then the user hooks-up a filter and blower combination of some sort to suck any mold spores and other contaminants through a filter for discharge from the blower. Governmental requirements are strict with regard to the amount of vacuum or negative air pressure permitted within the containment room during this process. The limit is five to seven Pascals of negative air pressure. With conventional equipment, it sometimes becomes necessary to cut a slot or slots in the plastic wall of the containment room to prevent conventional blower/filter combinations from pulling an excess vacuum. If, during a long period of treatment, there is a power loss due to a storm or a maintenance person unplugging the blower, there is no longer a vacuum in the chamber, with the resultant possibility of spores exiting through the slots in the containment room wall that were cut by the technician. In the case of the present invention, with the adjustable valves according to the present invention, and to be described now, there is no necessity for compromising the integrity of the containment room by cutting or punching slots or holes in it.  
         [0023]    Referring now to FIG. 6A, this is a front view of one of the adjustable air flow valve assemblies, showing the face of the assembly which faces the interior of the chamber  11 . As shown in this view and in FIG. 6B, the illustrated air flow ring  51  which may be a steel cylinder, has a web rail  52  across it and secured to the inner wall of the ring. This rail has an upturned portion at each end as at  53  and which has a downwardly opening notch  54  so that portion  53  can serve as a hook. A plate  56  is received on the back side of this rail and is fastened to it by a bolt  57  through the center of the plate and rail, and is prevented from turning inside the ring by a forwardly turned flange  58  engaging the upper edge  59  of the rail  52 .  
         [0024]    A plate  61 , identical to plate  56 , is mounted to bolt  57  behind plate  56  and can freely turn on bolt  57 . It too has a flange such as  58  but it is turned backward and can be used as a handle or sort of knob to enable a technician to turn the plate  61  relative to  56  to any extent desired. Thus, the edge  63  of the rearwardly turned flange can be located anywhere from a position where it is precisely parallel to the flange  58 , thus closing the ring entirely, to a position where it is again parallel to flange  58  but creates an opening which is fifty percent that of the hole in the panel in which the ring is mounted. The position shown in FIG. 6A is approximately sixty degrees open. When the desired adjustment has been made to reduce flow sufficiently to obtain the Pascal number usually between 5 and 7 desired for the containment room, the ring can be hooked onto the back panel  17 C of the chamber by inserting the hooks  53  in the slots  66 U provided at each side of the opening, such as  17 U, whereupon the downwardly opening notch  54  of the hook engages the bottom of the slot  66 U beside the opening to retain the air flow ring and valve assembly on the back panel of the chamber. The same construction with slots  66 L is provided for the valve assembly for the lower opening  17 L. Only one or both of these assemblies can be used and adjusted as desired for the particular size and requirements of the containment room to which they are attached, either directly or through flexible hose.  
         [0025]    So it can be seen that, instead of cutting the wall of the containment room to get the desired negative pressure when coupled to a conventional blower, the throttle plates according to the present invention can be adjusted by the technician at the outset to provide the desired level of negative air pressure by simply closing the plates to the extent needed. If, after making an adjustment, it is found to be necessary to make a further adjustment, the valve assembly can be simply lifted off the back panel, adjustment made to the plates, and the valve assembly put back on the chamber. It is not necessary to provide a special seal or taping of the valve assembly to the chamber back panel because, any time that the containment chamber is hooked up to the operating filter/blower combination, the blower will be running and pulling air into the filter, whether the air comes from the area in which the blower/filter combination is located, or from the containment room.  
         [0026]    The construction and mounting of the valve assemblies and their sizing makes it possible to readily connect standard, non-insulated flexible tubing snuggly fitting or taped to the outer surface of the valve assembly, with the other end of the tube sealed by tape to the wall of the containment room. Alternatively, the tubing can be eliminated and the plastic wall film of the containment room can be cut with two ten-inch diameter holes, and the valve assemblies taped tight to the film around the holes. Then the filter chamber can be backed up to the wall of the containment room and the valve assembly simply hooked in place on the back panel of the chamber.  
         [0027]    Referring now to FIGS. 7A and 7B, the cover plate  38  mentioned briefly above, includes the metal plate itself  71 , to which loops  39  are affixed at diametrically opposed locations. It also includes a seal ring  72  of resilient closed-cell foam adhesively adhered to the back side of the plate at  73 . The foam is typically three inches deep from the plate to the rear edge  74  of the foam and is of a diameter and shape compatible with the ten inch diameter opening  16 H in the front wall  16  of the chamber to seal closed the chamber when the unit is not in use. It also appropriately fits the blower motor cooling air intake opening  33  of the blower assembly to plug that opening when the blower assembly and the chamber are strapped together for use in a drying job. The foam is a custom, die-cut non-permeable foam and, being flexible, will fit the contour of the motor and air intake without leakage. Regarding cover plate  38 , once the blower has been removed, this cover plate with three inch seal can be strapped onto the front end of adapter  27  or directly onto front panel  16  and covers the clean side of the HEPA filter. This will prevent the clean side of the HEPA filter from contamination during removal from the job site and storage.  
         [0028]    The illustrated HEPA filter assembly itself comprises a standard molded plastic filter rack stacked with 24×12×12, 99.97 percent HEPA filtering media as provided by the Air Handler Organization. It has a “mini-pleat, V-bank” configuration. HEPA-type filters of other manufacturers and configurations might be useful alternatives.  
         [0029]    To conveniently carry the blower assembly from job-to-job along with the HEPA filter chamber at the same time, slots are provided at  21 F and  21 R (FIG. 1) in the upstanding flange or fence  21  of the chamber. Straps, preferably with hook-and-loop end portions are passed through these slots and over the blower when placed on top of the chamber for traveling. One of the straps passes through the slots  21 R and is typically passed through the handle opening on the blower. The other strap is passed through the slots  21 F and is strapped over the discharge snout of the blower. Thus, the top of the chamber serves as a transport and storage tray for the blower. In this way, the person handling the apparatus can easily transport both the chamber and the blower from place to place by rolling the combination along in the manner of a conventional hand-truck operation.  
         [0030]    Finally, although not mentioned above, a ⅛ th  inch thick soft rubber seal is typically glued or otherwise secured to the rear face of the front snout flange  28  to seal against the front face  16  of the chamber. An example of the bulb-type seal  31  is a push-on trim weather strip SKU#132X2565N as sold by J. C. Whitney, Inc. As mentioned above, to facilitate adaptation of this snout to different heights of blower intakes, the screws or bolts  44  are installed with their heads on the outside of the flange  28  and shafts passed through the slots  16 S in the front of the chamber, and are held in place by suitable locknuts engaging the inside face of wall  16  and sufficiently snugged so as to enable moving the snout up or down as needed to adapt to the blower intake. Being locknuts, preferably of the elastic or plastic-insert type, they will not back off from vibration or otherwise during the passage of time. Also, the banding or strapping or belting can be of a variety of flexible materials, referred to herein as straps. The hook-and-loop features are most convenient.  
         [0031]    Additional provisions can be provided such as a vacuum gauge at  76  and recessed lifting handles in the side walls as at  77  in FIG. 1. The assembly without the separate blower is about  32  inches high,  22  inches wide, and  20  inches deep. Its weight is between 30 and 40 pounds. Conventional carpet dryer blowers, “Tempest” brand or “Drieaz” brand or other brands having a housing with a carrying handle and having a blower fan or wheel and drive motor inside, can be used. The chamber will flow 900 to 1100 cubic feet of air per minute, depending on the blower strapped to it.  
         [0032]    While the invention has been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character, it being understood that only the preferred embodiment has been shown and described and that all changes and modifications that come within the spirit of the invention are desired to be protected.