the invention summarized above and defined by the enumerated claims may be better understood by referring to the following description , which should be read in conjunction with the accompanying drawings . this description of an embodiment , set out below to enable one to build and use an implementation of the invention , is not intended to limit the invention , but to serve as a particular example thereof . those skilled in the art should appreciate that they may readily use the conception and specific embodiments disclosed as a basis for modifying or designing other methods and systems for carrying out the same purposes of the present invention . those skilled in the art should also realize that such equivalent assemblies do not depart from the spirit and scope of the invention in its broadest form . in an effort to avoid the above - described disadvantages , a portable , modular air purification unit is provided . as shown in fig1 , the modular air purification unit according to a first preferred embodiment is shown generally at 100 , and comprises an inlet section 110 , a filter section 120 , and a blower section 130 . inlet section 110 is provided an inlet coupling 111 configured to receive a flexible hose or other conduit , or alternately to simply serve as an open inlet to the filter assembly . inlet coupling 111 may be integrally formed with , embedded in , or otherwise rigidly and sealingly attached to the body of inlet section 110 , which preferably is formed of plastic or other lightweight , inexpensive material . one or more clamp members 112 are preferably provided that , when tightened , pull inlet section 110 towards filter section 120 along seam 115 . preferably , a free end of inlet section 110 intended for mating with filter section 120 is configured with an interface to tightly fit with the inlet end of filter section 120 . thus , when inlet section 110 is so connected to filter section 120 , a tight seal exists that will prevent most contaminants from entering the air purification unit 100 through seam 115 . nonetheless , as the seam 115 is positioned upstream of the filter assembly , and because a lower pressure condition exists inside of inlet section 110 and filter section 120 than outside of unit 100 , any leakage would occur in the form of outside air flowing into the unit 100 before the filter section 120 , ensuring that any such leakage air is filtered before being exhausted from blower section 130 . in an alternate embodiment , the filter section 120 can be constructed of a single unit with the inlet section 110 and inlet coupling 111 fully integrated in a single shell . filter section 120 comprises a rigid outer shell 122 , preferably formed of plastic or other inexpensive , lightweight material . inside of the rigid outer shell 122 is a rigid filter assembly 200 ( fig2 ) of standard construction , selected for the threat / contagion environment in which the unit 100 is intended to be used . such filter assembly 200 may be configured to filter dust , chemicals , gases , biological agents , etc ., as is known in the art . the interior of filter section 120 is preferably provided a ledge at a first end 123 , such as the end adjacent inlet section 110 , configured to support the base of such filter assembly 200 . when positioned vertically , filter assembly 200 may be dropped into filter section 120 , and when so positioned ( with minimal clearance between the filter frame and the interior edges of the end walls of filter section 120 ), a bead of urethane ( or other flexible sealing material ) is applied to the seam between the interior edges of filter section 120 and the end walls of the filter assembly , such that the only available flow path through filter section 120 is through the filter assembly 200 . as the filter is intended as a disposable unit , and the outer shell 122 of filter section 120 is formed of an inexpensive , generally lightweight material such as plastic , the entire filter section 120 may simply be disposed of and replaced when it comes time to replace the filter . in this way , a new filter assembly 200 having the factory seal between the frame of the filter and the shell 122 can be assured with each new filter application . blower section 130 likewise comprises a rigid outer shell 134 formed of lightweight , inexpensive material , and is connected to filter section 120 along seam 125 . seam 125 is preferably formed with the same construction as seam 115 to ensure a tight seal between filter section 120 and blower section 130 . the exhaust end of blower section 130 comprises an outlet coupling 135 configured to receive a flexible hose or other conduit , or alternately to simply serve as an open outlet from the air purification unit 100 . outlet coupling 135 may be integrally formed with , embedded in , or otherwise rigidly and sealingly attached to the body of blower section 130 . internal to blower section 130 is preferably a motor driving a blower unit , comprising at least a fan that is positioned with respect to a fan coupling 210 ( fig2 ), such that the plane of differential pressure on either side of the fan is no further downstream than the free end 213 of the fan coupling 210 . as shown in fig2 , the filter assembly 200 ( shown in phantom ) is provided inside of filter section 120 . filter assembly 200 is preferably provided a fan coupling 210 extending away from the second end 124 of filter section 120 and into blower section 130 when the unit 100 is fully assembled . fan coupling 210 is preferably configured such that when filter section 120 is joined to blower section 130 the plane of the pressure differential at the fan is no further downstream than the free end 213 of the fan coupling 210 . in this manner , the air surrounding the fan coupling 210 is at the higher pressure of the differential pressures on either side of the fan , which higher pressure is at least greater than the pressure outside of the blower unit . given this assembly , even in the event of an imperfect seal between the fan coupling 210 and the blower section 130 , the risk of leakage of contaminated air through the seam 125 between the filter section 120 and the blower section 130 is eliminated , as the pressure differential between the inside of the modular blower unit 100 and outside of the blower unit will cause any leakage to flow from inside the unit 100 ( which air has already passed through and been cleaned by filter section 120 ) to outside the unit . referring to fig3 , a control panel 132 accessible from the exterior of blower section 130 allows monitoring and adjustment of the fan housed inside of blower section 130 . an on / off switch 310 may be provided . the control panel may also optionally provide a pressure indicator 315 for the airflow through filter section 120 . control 320 enables manual adjustment of the speed of the fan . operating indicating lights 325 provide a visual indication of the system condition . optionally , the control panel 132 may enable monitoring of the pressure in an attached room or shelter by connecting an appropriate detector to a monitor input 330 . such remote pressure monitoring also enables logging of data as selected by the user . data logging can be accomplished based upon specific time intervals or upon specific events , such as an alarm condition , such events to be determined by the user . an alarm condition may be revealed by visual indication 325 or by an audible alarm 335 . in some embodiments , the data logger may be internal to the unit or may be connected to a remote recorder , such as a personal computer or other external device . additionally , the user may adjust the alarm settings , as conditions require . the invention has been described with references to a preferred embodiment . while specific values , relationships , materials and steps have been set forth for purposes of describing concepts of the invention , it will be appreciated by persons skilled in the art that numerous variations and / or modifications may be made to the invention as shown in the specific embodiments without departing from the spirit or scope of the basic concepts and operating principles of the invention as broadly described . it should be recognized that , in the light of the above teachings , those skilled in the art can modify those specifics without departing from the invention taught herein . having now fully set forth the preferred embodiments and certain modifications of the concept underlying the present invention , various other embodiments as well as certain variations and modifications of the embodiments herein shown and described will obviously occur to those skilled in the art upon becoming familiar with such underlying concept . it is intended to include all such modifications , alternatives and other embodiments insofar as they come within the scope of the appended claims or equivalents thereof . it should be understood , therefore , that the invention may be practiced otherwise than as specifically set forth herein . consequently , the present embodiments are to be considered in all respects as illustrative and not restrictive .
a modular air filtration unit having a disposable filter section separable from an inlet cap and a blower section . the modular air filtration unit is of rugged , lightweight construction and eases the interchange of used filter assemblies without jeopardizing leakage that might cause contamination of the intended clean environment .