Abstract:
A portable air filtration and purification system with a portable housing having three sides and an open area. The open area facilitates filter replacement. A pre-filter is positioned within the housing. A fan assembly having a fan housing and fan blades is also positioned within the housing and is adjacent the pre-filter. A post-filter is adjacent the fan assembly and is positioned within the housing such that the pre-filer and the post-filter sandwich the fan assembly. The pre-filter intercepts the air flow into the portable air filtration and purification system before the air flows through the fan. The post-filter intercepts the air after it flows through the fan.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application takes priority from U.S. Provisional Patent Application 62/261,415, filed Dec. 1, 2015, the entirety of which is incorporated by reference herein. 
     
    
     FIELD OF INVENTION 
       [0002]    The invention relates in general to portable air filtration and purification units. 
       BACKGROUND OF INVENTION 
       [0003]    Chronic allergy and asthma sufferers appreciate the need for clean air and understand that many harmful particulates may be suspended in air. Pollen, pet dander, smoke, dust, mold, and viruses are examples of pollutants that cause symptoms of allergies and asthma that are found in air. To combat these and other pollutants companies and individuals in general have been seeking the aid of air filtration devices as stand-alone units or units that attach to HVAC systems. The problem with these units of the past is that, like HVAC, they focus on volume of air movement in cubic feet per minute (cfm), which does not allow the filtration portion of the device to properly or efficiently clean the air going through it. A slower, constant air movement across the filtration portion may significantly increase the efficiency of the device and drastically reduce the number of pollutants to which people are being exposed. There exists a need to develop an air filtration and purification unit that does not focus on volume of air movement but instead focusses on constant air movement and that would clean the air better than prior devices. The unit should be quiet, portable, light weight, and easy to maintain. 
       BRIEF SUMMARY OF INVENTION 
       [0004]    A stand-alone, portable air filtration and purification unit that requires standard 110V electricity to operate and can easily be moved from room to room in a household, office, or industrial setting. The unit may include a sheet metal shroud which houses an internal fan and two M11 or better filters. One of the filters—a pre-filter—is positioned such that the air enters the pre-filter before the air passes through the fan. The second filter—a post filter—is positioned such that the air passes through the second filter after the air passes through the fan. A dial switch may be used for selecting the fan speed. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0005]      FIG. 1  is a perspective view of the air filtration and purification unit according to an embodiment. 
           [0006]      FIG. 2  is an exploded view of the air filtration and purification unit of  FIG. 1 . 
           [0007]      FIG. 3  is a cross-sectional view of the air filtration and purification unit of the  FIG. 1  taken along line  3 , 4 - 3 , 4 . 
           [0008]      FIG. 4  is a cross-sectional view of the air filtration and purification unit of  FIG. 1  showing the path of the air through the unit taken along line  3 , 4 - 3 , 4 . 
           [0009]      FIG. 5  is a perspective view of the air filtration and purification unit according to a second embodiment. 
           [0010]      FIG. 6  is an exploded view of the air filtration and purification unit of  FIG. 5 . 
           [0011]      FIG. 7  is a cross-sectional view of the air filtration and purification unit of  FIG. 5  taken along line  7 - 7 . 
           [0012]      FIG. 8  is a cross-sectional view of the air filtration and purification unit according to a third embodiment. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0013]    Embodiments will now be described in detail with respect to an apparatus and method for assessing skilled professional qualities reflecting the inventors&#39; present preferred embodiments and the best means for practicing the invention. Those skilled in the art will recognize that the embodiments described herein are subject to modification and alteration without departing from the teaching herein. Therefore, the present discussion should not be considered limiting but an exemplification of the features of the invention. 
         [0014]    In the illustrated embodiment in  FIGS. 1-2 , an air filtration and purification unit  1  is shown. The air filtration and purification unit  1  has a shroud or housing  100 , a pre-filter  101 , a box fan assembly  102 , and a post-filter  103 . The pre-filter and post filters  101 ,  103  sandwich the fan assembly  102 , and are held in place by clips, clamps, or crimping  111 . In the illustrated embodiment, filters  101 ,  103  are identical. 
         [0015]    The shroud  100  surrounds the pre-filter  101 , the fan assembly  102 , and the post-filter  103  on at least three sides and further includes lips  107  on all three sides which act as stops so the filter does not fall out of place. At least one side may be open to allow for easy replacement of filters  101 ,  103 . The shroud  100  may be made from metals such as stainless steel, galvanized steel, aluminum, plastics, such as polycarbonate, or any appropriate materials known in the art, whether now known or later developed. On the exterior of the shroud  100 , located on top of the unit is a fan speed selection switch  104  which may have high, medium, low, and off positions. Also on top of the shroud  100  is a handle  112  for easy movement and portability of the air purification and filtration system. It is understood that the thickness of the filters will alter the dimensions of the shroud  100  and does not limit the invention, i.e. 20×20×2 inch filters, 20×20×4 inch filters. It is understood that an X-pattern grid filter holder may also be used herein with the invention. 
         [0016]      FIG. 3  shows a cross-sectional view of an air filtration and purification unit  1 . Air will flow in direction A. The filters  101 ,  103  may be made from fibrous material, paper, or other known or yet to be known materials in the art. The filters  101 ,  103  are pleated with individual pleats  110 . These pleats  110  are folded such that they create a 45 degree isosceles triangular pattern in a uniform pattern. A standard efficient filter is made from a MERV rated material as is known in the art, and then is folded a pre-set number of times (creating pleats) for a given standard dimension, thereby having a set surface area and length of material used that is known in the art that will create a MERV rated filter. The pleated design of the filters  101 ,  103  have less pleats  110  than a standard efficient filter and therein use less surface area, but still are efficient to be rated to a Minimum Efficiency Reporting Value (MERV) rating of 11 or better, which goes against the logic that the more pleats (or surface area) the better the filtration of the created filter. 
         [0017]      FIG. 4  shows the flow of air  200  through the air filtration and purification unit  1 . The air flows through the pre-filter  101 , then through the fan assembly  102 , and thereafter through the post filter  103 . By placing the pleats  110  at angles with respect to one another, the air flow  200  splits to create a Venturi effect at this first constriction. The fan assembly  102  controls the speed of the air flow  200 , and at slower fan blade speeds, the filters  101 ,  103  can clean without harming the filters  101 ,  103 . The filters  101 , 103  are placed at opposite ends of the fan assembly  102 . The split air flow  200  has the added advantage of reducing the noise of the air flow  200  through the filtration and purification system. In the addition, the filters  101 , 103  may by pleated in a variety of ways and will be further discussed below, and the number of pleats may be varied to slow the air flow  200 . 
         [0018]    By using the post filter  103  after the air passes through the fan  102 , the air is defused and again goes through a Venturi effect as it passes through the post filter  103 , which cleans as much as 40% more than using the pre-filter  101  only. As a result, the filters  101 ,  103  last much longer and clean better. 
         [0019]    Current air handling and heating, ventilation, and air conditioning (HVAC) systems are designed for high air speed and air volume (i.e between 2.5 m/s to 30 m/s dependent upon the size of the system). The use of the pre-filter  101  and the post-filter  103  in such HVAC systems would create too much drag or resistance to the air flow, and such systems would not operate correctly. Accordingly, the fan assembly  102  should be selected so that it has a lower, slower air speed and volume (e.g., 0.2 m/s to 0.666 m/s), which allows the system to clean the air more thoroughly and more efficiently, and preserves and prolongs the life of the filters  101 ,  103 . Slower air speed/volume fans are also generally less expensive and quieter, so their use in this application may well impart an economic advantage to this air filtration and purification system, as well as a quieter, more pleasant environment. Moreover, slower speed fans  102  are typically smaller and weigh less than high speed, high volume fans, making the portable air filtration and purification system easier to move and position. Indeed, testing has shown that use of the fan  102  to cause the air to slow down and circulate within the unit  1  allows for more particulates in the air to be captured, such that the air  200  ultimately exiting the post-filter  103  is substantially cleaner as compared to the air exiting prior art filtration systems. 
         [0020]    It is foreseen that the filters  101 ,  103  may be replaced with standard high efficiency pleated filters with a MERV rating of 8 or better as known in the art and this would be within the scope of the invention. It is also foreseen that they may be any combination of the filters disclosed herein and standard high efficiency pleated filters may be used. 
         [0021]    In the illustrated embodiment in  FIGS. 5-7 , an air filtration and purification unit  2  is shown. The air filtration and purification unit  2  has a shroud or housing  300 , a pre-filter  301 , a box fan assembly  302 , and a post-filter  303 . The air filtration and purification unit  2  is substantially similar to the air filtration and purification unit  1 , with the exception of the filters  301 ,  303  utilized in the embodiment. The pre-filter and post filters  301 ,  303  sandwich the fan assembly  302 . 
         [0022]    The pre-filter  301  may be made from fibrous material, paper, or other known or yet to be known materials in the art. The pre-filter  301  may be dimensioned to be 20×30×2 inches or a standard filter size known in the art. The pre-filter  301  has five individual pleats  320 ,  322 ,  323 ,  325 ,  327  ( FIG. 7 ) with the pleats facing towards the fan in the direction of the air A. The outer pleats  320 ,  327  are angled from a top  329  to a bottom  330  of the shroud  300  at an angle C with respect to the horizontal between 50 and 60 degrees, preferably at 55 degrees and then folded back at an angle D with respect to the horizontal between 55 and 65 degrees, preferably at 59.7 degrees. The inner pleats  322 ,  325  adjacent the outer pleats  320 ,  327  are angled from the outer pleats  320 ,  327  at an angle E with respect to the horizontal between 35 to 45 degrees, preferably at 40.6 degrees and then folded back at an angle F with respect to the horizontal between 45 and 55 degrees, preferably at 48.8 degrees. The center pleat  323  is angled from the inner pleats  322 ,  325  at an angle G with respect to the horizontal between 25 and 30 degrees, preferably at 28.6 degrees. The non-uniform folding pleated design of the pre-filter  301  and post-filter  303  in unison outperform current known in the art standard uniform pleating designs having multitudes of pleats in the same dimension. The pleated design of the pre-filter  301  filters uses less material (in comparison to a same dimensioned standard pleated filter) due to the nature of the curves and also filters in the 0.3 μm range to be rated to a MERV rating of 11 or better. The pre filter  301  is better rated than currently known in the art standard pleated using material with a MERV rating of 13-15 that have more uniform horizontal pleats or folds (not shown) and use a greater surface area having the same dimensions, i.e. 20×20×2 inches. 
         [0023]    It is foreseen that the pre-filter  301  may be utilized to test different filtrations efficiencies by observing the filtration efficiency of a single pleat design at the above noted angle ranges through the air filtration and purification unit  2 . This efficiency can then be compared to a standard pleated filter having the same dimensional size. It is foreseen that the pre-filter  301  may be oriented on either side of the fan or utilized as both the pre-filter  301  and the post-filter  303 . 
         [0024]    The post-filter  303 , likewise may be made from fibrous material, paper, or other known or yet to be known materials in the art. The post-filter  303  may be dimensioned to be 20×20×2 inches or any standard filter size known in the art. The post-filter  303  has several individual pleats  310  pointed in the direction of the airflow A, and each pleat  310  is angled downwardly with respect to a horizontal, at an angle A between 25 to 35 degrees ( FIG. 7 ) preferably at 29.7 degrees and then folded over itself at an angle B between 10 to 20 degrees with respect to the horizontal, preferably at 14.2 degrees. The pleated design of the post-filter  303  filters uses less material and therefore less surface area (in comparison to a same dimensioned standard pleated filter) due to the natural of the downward curves and also filters in the 0.3 μm range to be rated to a MERV rating of 11 or better. The post filter  303  is better rated than currently known in the art standard pleated filters using materials with a MERV rating of 13-15 that have more uniform horizontal pleats (not shown) and use a greater surface area. The non-uniform angular design may not be made using standard pleating machinery. The post-filter  303  may be oriented on either side of the fan or utilized as both the pre-filter  301  and the post-filter  303 . 
         [0025]      FIG. 8  shows a cross-sectional view of another embodiment of an air filtration and purification unit  3 . The filters  401 ,  403  may be made from fibrous material, paper, or other known or yet to be known materials in the art. The filters  401 ,  403  may be dimensioned to be 20×20×2 inches or a standard filter size known in the art. The pre-filter  401  and the post filter  403  are identical in the illustrated embodiment. The filters  401 ,  403  have several individual pleats  410  oriented in the direction of air A, and each pleat  410  is angled downwardly with respect to a horizontal H, at an angle H between 55 to 65 degrees, preferably at 60 degrees and then folded over itself at an angle J between 50 to 55 degrees with respect to the horizontal H, preferably at 52 degrees. From there the material is wrapped about rod or conduit  420  that is held in place by a bearing (not shown). 
         [0026]    The pleated design of the filters  401 ,  403  were tested at several downwardly sloping angles that approached 90 degrees or vertical (which will not allow any air through), and these angles H, J were determined to filter out the most microbial particles at the 0.3 μm range, thereby making a MERV 15 though utilizing material with MERV rating of 11. One result of such a test given by Assuredbio is given below. 
         [0000]    
       
         
               
             
               
               
               
               
             
               
               
               
               
             
           
               
                 TABLE 1 
               
             
             
               
                   
               
               
                 Test Results for Standard Filter MERV rating 11 
               
             
          
           
               
                 Species indentification 
                 Spore/m 3  of Air Inside 
                 Spore/m 3  of Air Outside 
                 (%) of Detected Species 
               
               
                   
               
             
          
           
               
                 
                   Acremonium strictum 
                 
                 ND 
                 ND 
                 0.00 
               
               
                 
                   Alternaria alternata 
                 
                 2,065 
                 2,503 
                 12.52 
               
               
                 
                   Aspergillus niger/awamori/foetidus/phoenicis 
                 
                 ND 
                 ND 
                 0.00 
               
               
                 
                   Aspergillus flavus/oryzae 
                 
                 ND 
                 ND 
                 0.00 
               
               
                 
                   Aspergillus fumigatus, Neosartorya fischeri 
                 
                 ND 
                 3,517 
                 0.00 
               
               
                 
                   Aspergillus ochraceus/ostianus 
                 
                 ND 
                 ND 
                 0.00 
               
               
                 
                   Aspergillus penicillioides 
                 
                 ND 
                 ND 
                 0.00 
               
               
                 
                   Aspergillus restrictus/caesillus/conicus 
                 
                 51 
                 51 
                 0.31 
               
               
                 
                   Aspergillus sclerotiorum 
                 
                 ND 
                 ND 
                 0.00 
               
               
                 
                   Aspergillus sydowii 
                 
                 ND 
                 ND 
                 0.00 
               
               
                 
                   Aspergillus unguis 
                 
                 ND 
                 ND 
                 0.00 
               
               
                 
                   Aspergillus ustus 
                 
                 ND 
                 ND 
                 0.00 
               
               
                 
                   Aspergillus versicolor 
                 
                 ND 
                 ND 
                 0.00 
               
               
                 
                   Aureobasidium pullulans 
                 
                 ND 
                 183 
                 0.00 
               
               
                 
                   Chaetomium globosum 
                 
                 ND 
                 ND 
                 0.00 
               
               
                   Cladosporium cladosporioides  svar. 1 
                 85 
                 40 
                 0.52 
               
               
                   Cladosporium cladosporioides  svar. 2 
                 ND 
                 ND 
                 0.00 
               
               
                 
                   Cladosporium herbarum 
                 
                 13,759 
                 8,342 
                 83.42 
               
               
                 
                   Cladosporium sphaerosperrnum 
                 
                 157 
                 ND 
                 0.95 
               
               
                 
                   Eurotium (Aspergillus) amstelodami/ 
                 
                 ND 
                 ND 
                 0.00 
               
               
                 
                   chevalleri/herbariorum/rubrum/repens 
                 
                   
                   
                   
               
               
                 
                   Epicoccum nigrum 
                 
                 ND 
                 ND 
                 50.00 
               
               
                 
                   Mucor amphibiorum/circinelloides/hiematis/ 
                 
                 ND 
                 ND 
                 0.00 
               
               
                   indicus/mucedo/racemosus/ramoissimus  and 
                   
                   
                   
               
               
                 
                   Rhizopus azygosporus/homothalicus/ 
                 
                   
                   
                   
               
               
                 
                   microsporus/oligoporus/oryzae 
                 
                   
                   
                   
               
               
                 
                   Paecilomyces variotii 
                 
                 ND 
                 ND 
                 0.00 
               
               
                 
                   Penicillium crustosum/camemberti/commune/ 
                 
                 ND 
                 ND 
                 0.00 
               
               
                 
                   echinulatum/solitum 
                 
                   
                   
                   
               
               
                 
                   Penicillium brevicompactum | stoloniferum 
                 
                 ND 
                 ND 
                 0.00 
               
               
                 
                   Penicillium chrysogenum 
                 
                 ND 
                 ND 
                 0.00 
               
               
                 
                   Penicillium corylophilum 
                 
                 ND 
                 ND 
                 0.00 
               
               
                 
                   Penicillium purpurogenum 
                 
                 ND 
                 ND 
                 0.00 
               
               
                 
                   Penicillium variabile 
                 
                 ND 
                 ND 
                 0.00 
               
               
                 
                   Penicillium glabrum/lividum/purpurescens/ 
                 
                 ND 
                 ND 
                 0.00 
               
               
                 
                   spinulosum/thomii 
                 
                   
                   
                   
               
               
                 
                   Rhizopus stolonifer 
                 
                 ND 
                 ND 
                 0.00 
               
               
                 
                   Scopulariopsis brevicaulis | 
                   fusca 
                 
                 216 
                 198 
                 1.31 
               
               
                 
                   Scopulariopsis chartarum 
                 
                 7 
                 7 
                 0.04 
               
               
                 
                   Stachybotrys chartarum  
                 
                 153 
                 ND 
                 0.93 
               
               
                 
                   Trichoderma viride/atroviride/koningii 
                 
                 ND 
                 ND 
                 0.00 
               
               
                 
                   Wallemia sebi 
                 
                 ND 
                 154 
                 0.00 
               
               
                 Total Spores 
                 16,493 
                 14,841 
                   
               
               
                   
               
             
          
         
       
     
         [0000]    
       
         
               
             
               
               
               
               
             
               
               
               
               
             
           
               
                 TABLE 2 
               
             
             
               
                   
               
               
                 Test Results for Filter 401/403 
               
             
          
           
               
                 Species indentification 
                 Spore/m 3  of Air Inside 
                 Spore/m 3  of Air Outside 
                 (%) of Detected Species 
               
               
                   
               
             
          
           
               
                 
                   Acremonium strictum 
                 
                 ND 
                 ND 
                 0.00 
               
               
                 
                   Alternaria alternata 
                 
                 ND 
                 ND 
                 0.00 
               
               
                 
                   Aspergillus niger/awamori/foetidus/phoenicis 
                 
                 ND 
                 ND 
                 0.00 
               
               
                 
                   Aspergillus flavus/oryzae 
                 
                 ND 
                 ND 
                 0.00 
               
               
                 
                   Aspergillus fumigatus, Neosartorya fischeri 
                 
                 ND 
                 ND 
                 0.00 
               
               
                 
                   Aspergillus ochraceus/ostianus 
                 
                 ND 
                 ND 
                 0.00 
               
               
                 
                   Aspergillus penicillioides 
                 
                 ND 
                 ND 
                 0.00 
               
               
                 
                   Aspergillus restrictus/caesillus/conicus 
                 
                 ND 
                 ND 
                 0.00 
               
               
                 
                   Aspergillus sclerotiorum 
                 
                 ND 
                 ND 
                 0.00 
               
               
                 
                   Aspergillus sydowii 
                 
                 ND 
                 ND 
                 0.00 
               
               
                 
                   Aspergillus unguis 
                 
                 ND 
                 ND 
                 0.00 
               
               
                 
                   Aspergillus ustus 
                 
                 ND 
                 ND 
                 0.00 
               
               
                 
                   Aspergillus versicolor 
                 
                 ND 
                 ND 
                 0.00 
               
               
                 
                   Aureobasidium pullulans 
                 
                 ND 
                 ND 
                 0.00 
               
               
                 
                   Chaetomium globosum 
                 
                 ND 
                 ND 
                 0.00 
               
               
                   Cladosporium cladosporioides  svar. 1 
                 7 
                 9 
                 50.00 
               
               
                   Cladosporium cladosporioides  svar. 2 
                 ND 
                 ND 
                 0.00 
               
               
                 
                   Cladosporium herbarum 
                 
                 ND 
                 ND 
                 0.00 
               
               
                 
                   Cladosporium sphaerosperrnum 
                 
                 ND 
                 ND 
                 0.00 
               
               
                 
                   Eurotium (Aspergillus) amstelodami/ 
                 
                 ND 
                 ND 
                 0.00 
               
               
                 
                   chevalleri/herbariorum/rubrum/repens 
                 
                 ND 
                 ND 
                 0.00 
               
               
                 
                   Epicoccum nigrum 
                 
                 7 
                 ND 
                 50.00 
               
               
                 
                   Mucor amphibiorum/circinelloides/hiematis/ 
                 
                 ND 
                 ND 
                 0.00 
               
               
                   indicus/mucedo/racemosus/ramoissimus  and 
                   
                   
                   
               
               
                 
                   Rhizopus azygosporus/homothalicus/ 
                 
                   
                   
                   
               
               
                 
                   microsporus/oligoporus/oryzae 
                 
                   
                   
                   
               
               
                 
                   Paecilomyces variotii 
                 
                 ND 
                 ND 
                 0.00 
               
               
                 
                   Penicillium crustosum/camemberti/commune/ 
                 
                 ND 
                 ND 
                 0.00 
               
               
                 
                   echinulatum/solitum 
                 
                   
                   
                   
               
               
                 
                   Penicillium brevicompactum | stoloniferum 
                 
                 ND 
                 ND 
                 0.00 
               
               
                 
                   Penicillium chrysogenum 
                 
                 ND 
                 ND 
                 0.00 
               
               
                 
                   Penicillium corylophilum 
                 
                 ND 
                 ND 
                 0.00 
               
               
                 
                   Penicillium purpurogenum 
                 
                 ND 
                 ND 
                 0.00 
               
               
                 
                   Penicillium variabile 
                 
                 ND 
                 ND 
                 0.00 
               
               
                 
                   Penicillium glabrum/lividum/purpurescens/ 
                 
                 ND 
                 ND 
                 0.00 
               
               
                 
                   spinulosum/thomii 
                 
                   
                   
                   
               
               
                 
                   Rhizopus stolonifer 
                 
                 ND 
                 ND 
                 0.00 
               
               
                 
                   Scopulariopsis brevicaulis | 
                   fusca 
                 
                 ND 
                 ND 
                 0.00 
               
               
                 
                   Scopulariopsis chartarum 
                 
                 ND 
                 ND 
                 0.00 
               
               
                 
                   Stachybotrys chartarum  
                 
                 ND 
                 ND 
                 0.00 
               
               
                 
                   Trichoderma viride/atroviride/koningii 
                 
                 ND 
                 ND 
                 0.00 
               
               
                 
                   Wallemia sebi 
                 
                 ND 
                 154 
                 0.00 
               
               
                 Total Spores 
                 13 
                 164 
                   
               
               
                   
               
             
          
         
       
     
         [0027]    The standard filter with a MERV rating of 11, there were 16,493 spores/m 3  detected inside and 14,841 spores/m 3  detected outside, whereas with the non-uniform angled downward pleat design filters  401 ,  403 , 13 spores spores/m 3  were detected inside and 164 spores/m 3  were detected outside. The results being a magnitude difference between the two filters tested, each being the same dimension and using the same MERV 11 rated material. 
         [0028]    The filters  401 ,  403  use less material (in comparison to a same dimensioned standard pleated filter) due to the natural of the downward curves and also filter in the 0.3 μm range. In a 20×20×2 inch filter size, 92 inches of material is used for a conventional known in the art pleated filter and in the filters  401 ,  403  at those dimensions, 82 inches of material is utilized. The filter  401 ,  403  is better rated than currently known in the art standard pleated designs made of the same material that have more uniform horizontal pleats (not shown) and use a greater surface area. It is foreseen that the air filtration and purification system  3  may be utilize any versions of filters previously discussed or a standard conventional filter. 
         [0029]    The portable air filtration and purification system disclosed herein may be used in areas where it is most needed or desired. It thoroughly cleans the air in the area in which it is placed, is easy to move, economical, is quiet, and prolongs the life of the filters. It may also be used with or in addition to current HVAC systems wherein each filter may be placed at beginning and ends of ventilation systems. It is also understood that the filters discussed herein may be utilized outside the air filtration and purification unit, in the realms of automotive engines, includes cars, boats, aircraft, as well as ventilation systems and human made environments (satellites, space shuttles, etc.). 
         [0030]    Thus, the present inventions have been described in detail with the understanding that the present detailed description is subject to modification and alterations without departing from the teaching herein. Therefore, the present invention should not be limited to the precise details presented herein but should encompass the subject matter of the claims and their equivalents, which follow.