Air filtration system having a removable diffuser

Abstract

An air filtration system includes a support structure, an enclosure coupled to the support structure and including an air outlet, a filter and a fan operatively coupled to the enclosure, and a diffusion screen configured to cover the air outlet. The diffusion screen includes a screen frame configured to be removably attachable to the enclosure with at least one releasable fastener, and at least a diffusion layer substantially spanning the screen frame to cover the air outlet to provide unidirectional or laminar air flow from the air outlet.

1 - 44 . (canceled) 
     
     
         45 . A mobile air filtration system comprising:
 (a) an enclosure assembly comprising:
 (i) an enclosure including an air inlet and an air outlet; 
 (ii) a screen frame operatively coupled to the air outlet of the enclosure; and 
 (iii) a unidirectional flow screen spanning the screen frame, the unidirectional flow screen having a downstream side defined along a single plane, the unidirectional flow screen covering the air outlet of the enclosure to result in unidirectional filtered air flow; the unidirectional flow screen:
 (1) including at least a single layer of material constructed and arranged to provide unidirectional filtered air flow from the air outlet such that filtered air flows in a single direction with generally parallel air streamlines; and 
 (2) creating only unidirectional parallel air streamlines across the flow screen, to shield an area from unfiltered air surrounding the area to result in filtered air that travels further to the area with lower levels of cross-contamination from particulates present in the surrounding unfiltered air than filtered air from an air filtration system without a unidirectional flow screen; 
 
   (b) a mobile housing unit comprising:
 (i) a housing having an air inlet and an air outlet, the housing being movable relative to the enclosure; 
 (ii) an air filter positioned between the air inlet and outlet; and 
 (iii) a fan positioned within the housing; and 
   (c) an air flow conduit operatively connecting the mobile housing to the enclosure assembly.   
     
     
         46 . The mobile air filtration system of  claim 45 , wherein the unidirectional flow screen comprises two layers of material. 
     
     
         47 . The mobile air filtration system of  claim 46 , wherein the two layers of material are a fabric material. 
     
     
         48 . The mobile air filtration system of  claim 47 , wherein the fabric material has a weave pattern. 
     
     
         49 . The mobile air filtration system of  claim 48 , wherein the weave pattern is a plain weave pattern. 
     
     
         50 . The mobile air filtration system of  claim 49 , wherein the weave pattern has pore sizes of no greater than 250 micrometers. 
     
     
         51 . The mobile air filtration system of  claim 49 , wherein the weave pattern has a nominal pore size of 150 micrometers. 
     
     
         52 . The mobile air filtration system of  claim 45 , wherein the air flow conduit is flexible. 
     
     
         53 . The mobile air filtration system of  claim 45 , wherein the air flow conduit is rigid. 
     
     
         54 . The mobile air filtration system of  claim 53 , wherein the mobile housing unit is located on a floor of a space served by the air filtration system. 
     
     
         55 . The mobile air filtration system of  claim 54 , wherein the enclosure is supported by the rigid conduit. 
     
     
         56 . The mobile air filtration system of  claim 45 , further comprising a return air conduit connected to the air inlet of the mobile housing unit. 
     
     
         57 . The mobile air filtration system of  claim 45 , wherein the filter is constructed and arranged to remove particulate matter, gaseous matter, and/or contaminate matter. 
     
     
         58 . An air filtration system for providing unidirectional filtered air to a desired zone; the air filtration system comprising:
 (a) a support structure;   (b) an enclosure coupled to the support structure and including an air outlet;   (c) an air filter in communication with the air outlet;   (d) a fan operatively coupled to the enclosure;   (e) a screen frame; and   (f) a unidirectional flow screen spanning the screen frame, the unidirectional flow screen having a downstream side defined along a single plane, the unidirectional flow screen covering the air outlet to result in unidirectional filtered air flow; the unidirectional flow screen:
 (i) being spaced from and parallel to the air filter; 
 (ii) comprising multiple layers of polymeric fabric constructed and arranged to provide unidirectional filtered air flow from the air outlet such that air flows in a single direction with generally parallel air streamlines; 
 (iii) having a weave pattern having pore sizes of no more than 250 micrometers; and 
 (iv) resulting in only unidirectional parallel air streamlines across the flow screen to shield a work area from unfiltered air surrounding the work area. 
   
     
     
         59 . An air filtration system according to  claim 58 , wherein the multiple layers include two layers of identical fabrics. 
     
     
         60 . An air filtration system according to  claim 58 , wherein the multiple layers include two layers of fabrics, with each layer having a different pore size. 
     
     
         61 . An air filtration system according to  claim 58 , wherein the unidirectional flow screen has a first layer of fabric spaced ⅝th inch from the air filter. 
     
     
         62 . An air filtration system according to  claim 61  wherein the unidirectional flow screen has a second layer of fabric spaced 1⅛th inch from the first layer of fabric. 
     
     
         63 . An air filtration system according to  claim 58  wherein the multiple layers include two layers of different fabrics. 
     
     
         64 . An air filtration system according to  claim 58 , wherein the support structure is constructed and configured to be mobile. 
     
     
         65 . An air filtration system according to  claim 64 , wherein the support structure comprises a plurality of wheels. 
     
     
         66 . An air filtration system according to  claim 65 , wherein the enclosure is movable with respect to the support structure. 
     
     
         67 . An air filtration system for delivering a unidirectional filtered air flow to shield a work area from unfiltered air, the air filtration system comprising:
 (a) a unit comprising:
 (i) a support structure; 
 (ii) an enclosure coupled to the support structure and including an air outlet; 
 (iii) an air filter housed in the enclosure; 
 (iv) a fan operatively coupled to the enclosure; and 
   (b) a unidirectional flow screen having a downstream side defined along a single plane, the flow screen being positioned to cover the fan filter unit outlet and spaced away from and parallel to the filter, the unidirectional flow screen comprising:
 (v) at least one layer of polymeric fabric having a weave pattern with pore sizes of 50-250 micrometers, the at least one layer being constructed and arranged to provide only unidirectional filtered air flow from the fan filter unit across the flow screen such that the filtered air flows to the work area in a single direction with generally parallel air streamlines; 
   (c) wherein cross-contamination of the filtered air flow by particulates present in the surrounding unfiltered air is less than that of an air filtration system having a fan filter unit without a unidirectional flow screen.   
     
     
         68 . An air filtration system according to  claim 67 , wherein the filtered air flow is laminar and has a velocity of about 90 feet per minute. 
     
     
         69 . An air filtration system according to  claim 67 , wherein the unidirectional flow screen is spaced 1¾ inches from the fan filter unit filter. 
     
     
         70 . An air filtration system according to  claim 67 , wherein the support structure is constructed and configured to be mobile. 
     
     
         71 . An air filtration system according to  claim 70 , wherein the support structure comprises a plurality of wheels. 
     
     
         72 . An air filtration system according to  claim 67 , wherein the enclosure is movable with respect to the support structure.