Portable modular vacuum system

A portable modular duct cleaning apparatus for cleaning heating, ventilating and air conditioning systems comprising;

• a modular vacuum generator unit comprising a housing, a vertical wall in said housing defining the housing interior into a fan chamber and a motor chamber and having an inlet and an outlet, a fan in said fan chamber and a variable frequency drive motor in said motor chamber operatively connected to said fan for driving said fan to cause air to flow into the inlet in the fan housing and through said outlet, castor wheels supporting said vacuum generator unit for movement along a surface,
• a modular Hepa filter unit including a housing having an inlet and outlet, said filter housing having a plenum chamber and a filter chamber, a Hepa filter positioned in said filter chamber, said filter housing positioned upon the vacuum generator housing, means releasably securing the Hepa filter unit to said vacuum generator unit, the inlet of said Hepa filter housing being disposed in communicating relation with the outlet of said vacuum generator housing so that air will flow through the inlet of the Hepa filter housing from the outlet of the vacuum generator housing,
• a modular prefilter unit including a housing having an inlet and outlet, means releasably securing said modular prefilter unit to said vacuum generator unit, said prefilter housing having a pair of vertically spaced apart apertured transverse walls traversing the interior thereof and forming the interior of said prefilter housing into an upper plenum chamber, an intermediate filter chamber and a lower collection chamber, said inlet of the prefilter housing communicating directly with the upper plenum chamber, said outlet of the prefilter housing communicating directly with the intermediate filter chamber, a plurality of similar vertically disposed open ended flexible tubular filter members positioned within said filter chamber, means securing the upper and lower end portions of the tubular filter members in the apertures of transverse walls, said transverse walls whereby said tubular members directly intercommunicate the plenum chamber, filter chamber, and collection chamber, said prefilter housing having a fitting secured to said inlet for connection to a conduit extending into a duct system to be cleaned whereby when said motor is energized a stream of entraining debris, dust and contaminants is directed into the upper plemum chamber and then into the intermediate filter chamber through the prefilter housing filters and then into the fan housing and thereafter through the Hepa filter for removing impurities and debris from the air stream.