Integral Vacuum Fan Housing
A filter box for a surface maintenance machine incorporating aspects of a fan housing. In one example, a filter box for a sweeping machine is provided with an impeller fan housing beneath a cylindrical filter. Operation of the impeller fan draws air from a debris hopper, through the cylindrical filter, and through an expansion chamber defined by a scroll conduit prior to outlet to atmosphere.
1 . A filter system for a mobile surface maintenance machine comprising:
a hopper adapted to receive debris from a sweeping brush; and
a filter box carrying at least one filter and a vacuum fan impeller and being externally provided relative to the hopper, said filter box being in air communication with the hopper so as to support a vacuum-based airflow through the hopper and said at least one filter.
2 . The system of claim 1 wherein the vacuum fan impeller is a closed impeller.
3 . The system of claim 1 wherein the filter box defines a portion of an expansion chamber which receives air from the closed impeller during machine operation.
4 . The system of claim 3 wherein the expansion chamber is defined by an axially expanding scroll.
5 . The system of claim 4 wherein the expansion chamber is center by an open conduit between the filter interior and the fan impeller center.
6 . The system of claim 2 further comprising a filter shaking mechanism to dislodge dust and debris from a surface of the filter, said dust and debris accumulating on a bottom of the filter box.
7 . The system of claim 3 wherein the dust and debris of the filter box are selectively passed through a conduit into the hopper.
8 . The system of claim 4 wherein a movable flap, biased by operation of the vacuum fan, controls the flow of dust and debris through the conduit and into the hopper.
9 . A filter housing comprising:
a molded plastic housing having an interior volume into which a filter is disposed and defining at least a portion of a vacuum expansion chamber.
10 . A filter comprising:
an integrated filter box containing a filter, said filter box being external to a hopper of a sweeping machine;
a filter shaking mechanism attached to the filter box; and
an impeller attached to the filter box.
11 . The filter of claim 10 wherein the filter box defines a portion of an expansion chamber surrounding at least a portion of the impeller.
12 . The filter of claim 11 wherein the expansion chamber maintains a generally constant radial distance from a center.
13 . The filter of claim 11 wherein the expansion chamber expands axially around the impeller blade.
14 . The filter of claim 10 wherein the filter box includes a conduit between the interior of the filter and the impeller.
15 . The filter of claim 10 further comprising a selectively operable duct for passing dislodged debris from the filter box into the hopper.
16 . A filter comprising:
a housing having an air inlet and a filtered air outlet;
a filter within the housing;
a vacuum fan connected to the housing and drawing air from the inlet toward the outlet;
an expansion chamber at least partially molded into the housing, said expansion chamber surrounding at least a part of the vacuum fan.
17 . A surface maintenance machine comprising:
a mobile chassis having a sweeping brush;
a hopper receiving debris thrown by the sweeping brush;
a filter box external to the hopper and being in selective air communication therewith, said filter box carrying a filter, a shaking mechanism and a vacuum impeller.
18 . The machine of claim 17 wherein the impeller is driven by a hydraulic motor.
19 . A surface maintenance machine comprising:
an integrated molded filter box external to a main debris hopper and carrying a filter and defining at least a portion of a curved expansion chamber proximate to a driven air impeller.
20 . The machine of claim 19 wherein the expansion chamber is generally circular.