Abstract:
A modular direct flow clean air delivery apparatus is disclosed that is particularly adapted for use in restaurants, banquet halls, meeting rooms, offices etc., where cigarette smoke and other pollutants need to be efficiently removed from the air in the room. The filtering and air moving apparatus may be mounted above a false ceiling in a whole room, or any part of a room, and includes remotely located air intakes and supplies, high capacity minipleat V-bank filters, and backwards curved impeller blowers mounted in the duct work between the intakes, supplies and the filtering apparatus for utmost efficiency and uncompromised air movement in a room. The modular apparatus may also be suspended from high ceilings with the use of rigid ductwork.

Description:
This invention relates generally to a modular air filtering apparatus, and more particularly, to stand alone air filtering apparatus for use in restaurants, banquet halls, meeting rooms, offices and the like that pick up, filter and exhaust air at remote locations across the false ceiling in a room. 
     BACKGROUND OF THE DISCLOSURE 
     Heretofore, several methods have been used to filter the air in meeting rooms, banquet halls, restaurants, offices and the like. One comprehensive apparatus for cleaning the air is to install filters, electrostatic precipitators, or the like in line in the duct work of an existing, heating, ventilating and air conditioning system shortly after the air leaves the furnace portion of the system. While this filtering apparatus treats all of the air going through the entire HVAC system, if a whole room in one building like a restaurant, only needs a portion of the total serviced by the heating, ventilating and air conditioning system, treated by filtration, that apparatus may be an expensive over-kill. 
     Another apparatus for filtering air in a room is a self-contained air filtering apparatus such as shown in U.S. Pat. No. 5,733,348. This patent discloses a filter, blower and air inlet and outlet all in one rectangular package suitable for positioning in a false ceiling in a room. Such an apparatus may prove to be inefficient in cleaning air at locations remote from the apparatus. In order to somewhat correct that problem, multiple self-contained units may have to be used in a single room, thereby driving up the cost and the expense of running and maintaining multiple units. Other apparatus, such as found in U.S. Pat. No. 4,905,578, may be utilized in clean rooms or the like. Other filtering apparatus may have a “room” that is made smaller and positioned within the ventilating apparatus such as shown in U.S. Pat. 4,108,051. This type of mechanism is inconvenient for use in large meeting rooms, restaurants, offices and the like. Another apparatus similarly used in a controlled material handling space is described in U.S. Pat. No. 5,487,768. This system has the same limitations with respect to transferring the use of a controlled space to the use of a room utilized such as a restaurant, banquet hall or the like. Another U.S. Pat. No. 4,726,824 discloses an air purification system suitable for use in a room. However, that system has ductwork not only in the ceiling of the room but outside the walls of the room, and would need to be implemented during the actual construction of the building or room. Such a system would be too expensive and require too much modification to be retrofitted into a room that already exists. 
     A need has developed for an improved modular air filtration system that may be expanded or contracted physically to be mounted on or above the false ceiling of a restaurant, banquet room, meeting room, office or the like to provide for filtration of the air in a room, or a specific portion of a room. 
     It is, therefore, an object of the present invention, generally stated, to provide a new and improved air filtration apparatus for use in restaurants, banquet halls, meeting rooms, offices and the like. It is a further object of the invention to provide a modular air filtration apparatus that exists separately from any heating and ventilating and air conditioning system therein and that may be mounted on or above the false ceiling of a room. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The features of the present invention which are believed to be novel are set forth with particularity in the appended claims. The invention may best be understood from the following detailed description of currently preferred embodiments thereof taken in conjunction with the accompanying drawings wherein like numerals refer to like parts, and in which: 
     FIG. 1 is a cross-sectional view of the single inlet backward curved centrifugal fan, constructed in accordance with the present invention; 
     FIG. 1 a  is a side elevational view of the housing for the fan shown in FIG.  1 . 
     FIG. 2 is a perspective view of a mini-pleat V-bank particle filter cartridge constructed in accordance with the present invention; 
     FIG. 2 a  is a perspective view of an activated carbon odor filter cartridge; 
     FIG. 3 is a perspective view of a first embodiment of an air supply/diffuser mounted on a false ceiling; 
     FIG. 3 a  is a perspective view of a second embodiment of an air supply/diffuser mounted on a false ceiling; 
     FIG. 3 b  is a side elevational view of the air supply/diffuser shown in FIG. 3; 
     FIG. 4 is a perspective view of an air filter box utilized in a “slimline” unit showing particle and odor filters mounted therein; 
     FIG. 4 a  is a perspective view of a combined air filter/return unit mountable on a false ceiling gridwork; 
     FIG. 5 is a diagrammatic view of a clean air delivery apparatus utilizing a single return, single supply flow pattern; 
     FIG. 6 is a diagrammatic view of a clean air delivery apparatus having single supply single return flow pattern utilizing a filter box in between; 
     FIG. 7 is a diagrammatic view of a clean air delivery apparatus utilizing a dual supply and single central return/filter; 
     FIG. 8 is a diagrammatic view of a dual supply and dual return clean air delivery system utilizing a horizontal flow filter box therebetween; 
     FIG. 9 is a diagrammatic view of a quad supply clean air delivery system utilizing a single return and combination filter box; 
     FIG. 10 is a perspective view showing the quad supply clean air delivery system shown in FIG.  9 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to FIGS. 1 and 1 a , the stand alone modular clean air filtering and delivery apparatus of the present invention moves air through the entire apparatus by means of a fan unit, generally indicated at  10  including an external housing or baffle  11 - 12  having a circular outlet  13  and a circular inlet  14  in connection therewith. Control circuitry for the fan motor is positioned in the electrical box  15 . 
     Referring to FIG. 1, the motor for the fan is an external rotor motor, generally indicated at  16 , and it includes a stator with windings  17 , and a rotor  18  which rotates on a shaft  19 . In this embodiment, the rotor  18  has mounted externally thereon a single inlet backward curved centrifugal fan, generally indicated at  20 . The fan  20  includes a plurality of backwardly curved blades  21 — 21  that direct the air through the fan in a direction parallel to the shaft  19 . Generally, in the preferred embodiment, the backward curved impellers are made with either plastic impellers on a disk of galvanized sheet steel, or are made entirely of galvanized sheet steel. The impellers are press fitted directly onto the rotor of the external rotor motor  18 . Maximum power consumption of backward curved impellers is reached in the low back pressure area as the back pressure increases. The use of backward curved impellers provides more efficient and less costly movement of air through the clean air delivery apparatus constructed in accordance with the present invention than that provided by prior known fans. The use of the single inlet backward curved centrifugal fan  20  in the fan unit  10  provides a more efficient enclosed fan unit which is constructed for air-tight use with flexible round duct work or spiral round ductwork (to be discussed in more detail below) than that heretofore known, which is an important aspect of the stand alone clean air delivery system of the present invention. 
     Referring to FIG. 2, a mini-pleat particle filter core or cartridge, generally indicated at 25, and sold under the trademark V-BANK, by Filtration Group of Joliet, Ill., includes a frame defined by end panels  26 — 26  (one shown) and connecting frame posts  27 — 27 . These filters are offered in two sizes, 24″×24″×12″ and 12″×24″×12″. The frame posts are typically 1″×11″×12″ the importance of which will be discussed in further detail below. The filtering media  28  is wound from one of the frame posts  27  through the ends of the various fingers  26   a ,  26   b ,  26   c ,  26   d  respectively, between end panels  26 — 26  in a V-shape or a pleat type arrangement and may also be layered with an outside portion and one or more inside media portions to increase the square footage of filtering media that may be enclosed in a single mini-pleat filter cartridge  25 . In operation, a single filter cartridge sized 2 feet by 2 feet by 1 foot may include up to 193 square feet of filtering media, and a cartridge sized 1 foot by 2 feet by 1 foot may include up to 97 square feet of filtering media. The extended media surface provides a very low resistance to air flow. A low pressure drop of air running through the filter cartridge results in lower energy costs and longer filter life. A minimum standard for such an air cleaning system would by 95% ASHRAE or better. The rigid frame and stable mini-pleat filter cartridge design not only distributes air substantially completely across the filter but also allows for a large variation in air flow and pressure drop without affecting the filter performance and efficiency. The performance is also not affected by repeated fan shut downs or changes in air flow velocities. Such a filter is rated a continuous air flow rates of up to 3,000 cubic feet per minute. 
     Referring to FIG. 2 a , an activated carbon filter panel, indicated generally at  30 , includes a thin, generally square frame  31  of 12×24×1, having a plurality of activated carbon particles  32  sandwiched between the one inch frame rails  31 — 31  and maintained therein by a mesh covering (not shown). 
     Referring to FIG. 3, a first embodiment of a ceiling mounted directional air supply diffuser, generally indicated at  33  is a square  2 ′ by  2 ′ metal structure that mounts on a false ceiling framework  34 , protrudes below the false ceiling frame and includes multi-directional dampers/louvers  36 — 36  that provide the air supply with eight-way adjustable dampers that direct the air both horizontally and vertically to insure proper air circulation. The adjustable louvers  36 - 34  provide for targeting the airflow around obstructions, if necessary, in desired directions and can control the air-volume by closing the louvers, if necessary. This embodiment is intended for better air control when used in rooms with higher ceilings. 
     Referring to FIG. 3 a , a second embodiment of an air supply diffuser, generally indicated at  40 , includes a flat bottom sheet  41  that mounts on a false ceiling grid work, and includes in this embodiment, permanent air directional louvers  41   41   a ,  41   b  and  41   c  that direct air in four differing directions. It should be noted that alternative bottom sheets (not shown) may have permanent louvers positioned for one-way flow, two-way, three-way, five-way, 6-way and 8-way flow, depending on a user&#39;s desires. FIG. 3 b  shows the plenum which can be permanently attached to the diffuser of FIG. 3 or  3   a  (FIG. 3 b  shows attachment to the diffuser in  3 ) that the air supply  33   a  includes a wedge shape body having opposed sloping sides  42 ,  42   a  (not shown), a flat angled top  44 , a relatively large flat rectangular rear wall  45  having a round duct receiving flange  46  thereon, and a small front door  47  hingedly attached to a framework (not shown) adjacent the bottom louvered panel  33 . Inside the air supply  33   a  a pair of 1″ by 24″ rails are adjacently fastened to the interior surfaces of the opposing side walls  42 ,  42   a  to provide for slidably mounting a pair of activated carbon filter panels  30 — 30  (FIG. 2 a ) therein above the bottom louvered panel  33 . This second embodiment air supply is used in connection with a “slimline” unit where space above the false ceiling is at a minimum. Referring to FIGS. 4 and 4 a , filter boxes used in the “slimline” system, generally shown at  50 , and in the regular installation, shown generally at  51 , are both rectangular boxes that have a filter cartridge  25  mounted therein for efficient air flow therethrough. As will be shown in more detail below, the separation of the fan unit from the filter box and its placement along the duct work is an important aspect of the present invention. 
     Filter box  51  is made of a rigid material, such as sheet metal, fiberglass, etc. so as to be air tight when installed. It includes a flat rectangular bottom  52  and top  53 , flat opposing sides  54  and  55 , each including one or more duct receiving flanges, such as  54   a , a closed end  56  (not shown) and an open end having an access door  57  thereon. Box  51  would typically be about 20″×12 ″×24″ or 20″×12″×47″ for a dual filter installation as shown. 
     On the inside of the filter box  51  are opposing pairs of 1″×1″×47″ rails  58 — 58  and  60 — 60  mounted about 13″ apart on the inside of the bottom and top panels  52 ,  53 , respectively, so as to face each other and allow a filter cartridge  25  and activated carbon panel  30  to be mounted therein about one inch apart with air flow being through the duct flange  54   a  and filter cartridge  25  first, to remove particles then through the activated carbon panel  30  to remove odors, then out through a duct flange (not shown) on rear panel  55 . Door  57  provides an opening for cleaning and replacing the particle filter cartridge  25  and odor filter panel  30 . 
     Referring to FIG. 4 a , a combination air return/filter box  50 , like air return  51 , is made of rigid sheet metal, fiberglass or the like. Air return/filter box  50  includes rectangular opposed side panels  65 - 66  a top panel  67  having at least one duct flange  68  therein for drawing air up through filter cartridge  25  and through an open mesh bottom screen  70 . A back panel  71  and an opposed door  72  is removably connected to side panel  66  by over-center type clamps  72   c ,  72   d , retained by hooks  66   a-d  (only one shown) on side panel  66  to provide an access door for removing and cleaning filter cartridge  25 . Along the interior sides of panels  65 - 66  adjacent the bottom thereof are mounted an opposed pair of 1″×1″×14″ rails  72 - 73  to provide a mounting for the frame of filter cartridge  25  to be slidably mountable thereon. The bottom mesh panel  70  (not shown) is sized to mount on a false ceiling grid, typically 24″×24″, with two filter cartridges  25  in line, but may be doubled in size to 24″×48″ with four filter cartridges thereon. 
     Referring to FIGS. 5,  6 , and  7 , various modular clean air filter and delivery apparatus configurations and air flow patterns are shown. In FIG. 5, an inline modular clean air delivery apparatus, constructed in accordance with the present invention, generally indicated at  85 , is utilized for cleaning or purifying the air in a rectangular room as shown by the outline. In-line clean air delivery apparatus  85  includes an air supply or diffuser  84 . In connection with the air supply  84  shown in FIG. 5, dampers or louvers in the supply are chosen to be directional as shown at  40  in FIG. 3 b  or adjustable as shown at  33  in FIG. 3 to direct air toward the return  87  on the opposing side of the room to obtain a direct flow pattern. These supplies also contain carbon odor filter(s)  30 . As mentioned previously, the air return  87  positioned on the opposing side of the room is a combination air return/particle filter box (FIG. 4 a ) that is mounted with the return to be flush with the false ceiling in the room. 
     Air is then directed upwardly through a grating or mesh screen  70  mounted in the bottom of the return  50  in FIG. 4 a , through the mini-pleat V-bank cartridge  25  and out the top of the return where an elbow (not shown) joins the return to the flexible ducting  88  that runs between the return and the remote supply  84  that includes an activated carbon panel  30 . Mediate the combination return filter  87  and the supply  84  is positioned the fan unit  10  consisting of the single inlet backward curved centrifugal fan  20  (FIG.  1 ). As indicated previously, the fan housing  11 - 12  makes up an efficient shroud for the centrifugal fan  20  and provides circular outlet  13  and inlet  14  for mounting the flexible duct work  88  in an air tight relation thereto. The combination of the flexible duct work and the completely shrouded fan unit  10  provides for very efficient cost-effective flow of air from the filter box/return  87  to the supply or diffuser  84 . 
     Also, it should be noted that fan  10  is pumping particle free air from the return/filter box  87  to and through the odor removing activated carbon panel  30 . 
     Referring to FIG. 6, a second configuration of an in-line clean air delivery apparatus, generally indicated at  90 , constructed in accordance with the present invention, not only includes a supply  91  positioned at one end of a room and a return  92  positioned at the opposing end of the room, but also includes a separate air tight filter box  93  positioned mediate the supply  91  and the return  92  above any false ceiling in the room. This configuration has been designated a “slimline” unit. In this embodiment  90 , the supply includes the flexible round duct work  88   a  extending therefrom and has the fan unit  10   a  positioned mediate the supply and the filter box  93  with an additional flexible duct work positioned between the inlet of the filter box and the return duct work  95  between the inlet of the filter box and the return. In operation, the air flow through the filter box  93  is horizontal and the V-pleat filter cartridges  25  and activated carbon filter cartridge  30  are positioned vertically (as shown in FIG.  4 ). 
     In one important aspect of the present invention, it has been found that in the preferred embodiments of the modular clean air delivery apparatus works more efficiently with the minipleat filter cartridges  25  (FIG. 2) positioned on the inlet or low pressure side of the fan unit  10 — 10   a . In this configuration, air is drawn through the filter medias  25 . As configured, the fan unit  10   a  is also kept cleaner by passing filtered air therethrough. In another important aspect of the present invention, the separation of the fan unit  10   a  from the filter box  93  allows the “slim line” filter box to be made smaller than heretofore known. The “slim line” system may be installed in rooms where the space between a false ceiling and a real ceiling is at a minimum, about 18 inches or less. Prior known filter boxes including a fan unit mounted integrally therein will not fit in such a confined area. 
     Referring to FIG. 7, a third configuration of clean air delivery apparatus, generally indicated at  100 , constructed in accordance with the present invention, is of the type that might be used in a long narrow rectangular room. While the apparatus shown in FIGS. 5 and 6 both feature one circular air flow path from one end of the room to the opposing end of the room, the apparatus  100  shown in FIG. 7 is intended to have two circular paths, each occupying one-half of the room shown in outline. The first circular path runs from the supply  101  across one-half of the room to the central return/filter box  102 . After the air is filtered it travels through flexible air duct  103  and the fan unit  10   b  back to the supply  51 . A second circular flow of air extends from the opposing supply  104  positioned at an opposing end of a room from supply  101 . Clean air travels out of the supply toward the middle of the room to the opposing side of the return/filter box  102  where it moves upwardly through the box and through the filters therein and thereafter through flexible ducting  105  and fan  10   c  back to the supply  104 . It should be noted that while the various configurations in-line apparatus shown in FIGS. 5,  6  and  7  disclose straight line air ducting, the flexible air ducting utilized in the present apparatus may be positioned to move around obstructions above the false ceiling of any room in which the clean air delivery apparatus is mounted. The use of the in-line in ducting fans  10   a-c  in connection with the ducting provides for efficient flow of air even when the ducting is curved or bent to flow around obstructions. As noted previously, each fan unit  10   a-c  is positioned downstream of the return/ filter unit  52  (low pressure side) to move filtered air therethrough. 
     Referring to FIG. 8, a second embodiment of a clean air delivery apparatus similar to that utilized in connection with FIG. 6 is shown with increased ducting for providing a single circular flow of air across a wider room than is shown in FIG.  6 . In the dual apparatus  60  shown in FIG. 8, a pair of supply diffusers  111 ,  111  supply air adjacent opposing corners of one end of a room toward the returns  112 — 112  positioned in the opposing end of the room. When the air enters the return  112 — 112 , it passed through flexible ducting  113 — 113  into a central enclosed filter box  114  containing both filter cartridges  25  and activated carbon panels  30  mounted vertically in the filter box for horizontal flow therethrough. After flowing through the filters  25 - 30 , the air is passed through flexible ducting  115 — 115  and fans  10   d — 10   d  back to the supply  111 — 111 . Notice again that the fan units  10   d  are positioned downstream of the filter box  114 . Again, the dual filter apparatus  110  shown in FIG. 8 is similar to the apparatus  80  shown in FIG. 6 for use in a narrower or smaller room than that shown at  60 . Both of these designs (FIGS. 6 and 8) use the “slimline filter” units. 
     Referring to FIGS. 9 and 10, a third embodiment of a clean air delivery apparatus, generally indicated at  120 , provides what might be termed a “donut” shaped air flow pattern that includes four supply plenums  121 — 121 , one located adjacent each corner of the room in which the air is to be filtered. The supplies  121 — 121  push clean filtered air across the activated carbon filter  30  before it is outwardly moved toward a central return  122 , which is a combination return and filter box. The filter box return  122  has an intake opening (FIG. 4 a ) and air travels upwardly through the filter box and then at right angles outwardly thereof at four locations around the periphery of the filter box  122  to flexible ducting  123 ,  124 ,  125  and  126 , each of which is connected via a backward curved centrifugal fan  10   e   10   e , to one of the external supplies  121 — 121 . Again, each fan unit  10   e  is positioned upstream of the return/filter box  122 . As shown most clearly in FIG. 9, the clean air delivery system  120  may be utilized in a room that has both smoking and non-smoking sections, with at least some of the supplies  121 — 121  positioned in a non-smoking section, the flow of air is from the non-smoking section to the smoking section rather than the reverse as long as the return is positioned over a part of the smoking section of the room. As shown most clearly in FIG. 10, the air flow from each of the supplies  121 — 121  flows downward and toward the center of the room where the return-filter box  122  is positioned. 
     A fourth embodiment of the present invention looks identical to the first three embodiments with the exception that the flexible ductwork is replaced with spirally formed rigid ductwork. While the first three embodiments included modules that mounted on false ceiling grid work, a need has developed for an alternative modular clean air delivery apparatus that can be suspended from a ceiling in a restaurant or the like. These modules are suspended from a  20  ceiling by wires similar to those used to suspend a false ceiling grid work itself As shown, in FIGS. 3 b  and  4   a , eye type flanges or ears,  123 — 123  in FIG. 3 b  and  124 — 124  in FIG. 4 a  allow suspension wires  125 - 126 , respectively, to be retained thereon. In restaurants, theatres, etc., the entire ceiling area, including utilities, is usually painted all black to become substantially invisible to a patron. The rigid spiral ductwork maintains the integrity of the complete apparatus in its suspended position. 
     Thus, a new and improved modular clean air filtering delivery apparatus including state of the art components to remove particles and odors from air in a room and deliver clean air to that room have been shown and described in what may be considered a “keep it simple” system (KISS) that provides superior air quality at low cost. Also, the apparatus provides for ease of installation above false ceilings, a flexible system design that allows for avoiding obstructions and other discontinuities in the false ceiling of a room and provides consistent very efficient performance with maximum air flow management. It may also be suspended from ceilings when used with rigid ductwork. 
     While four differing embodiments of the present invention have been shown and described, it will be apparent to those skilled in the art that many changes and modifications may be made without departing from the true spirit and scope of the present invention. It is the intent of the appended claims to cover all such changes and modifications which fall within the true spirit and scope of the invention.