dirt collection chambers 54 a 54 b and that supports a vacuum pump assembly 58 and a filter 72 mounting bracket 56 has a body that is preferably a single integral structure that is molded from plastic or some other suitable material mounting bracket 56 may however be made as more than one component without departing from the scope of this invention mounting bracket 56 may be generally circular in shape so as to be configured to fit within housing 32 however if the housing is manufactured with some other cross sectional shape such as square or rectangular a mounting bracket of similar cross sectional shape may be used without departing from the spirit of the present invention while the following description refers to the circular version of the mounting bracket 56 it will be understood by those skilled in the art that similar structures would be desirable on mounting brackets of other shapes referring to fig3 a 4 u2013 8 it may be seen that mounting bracket 56 has an upper surface 56 a and a lower surface 56 b and defines both a centrally located bore 68 and an aperture 70 mounting bracket 56 has a radially ribbed central portion 130 having a plurality of ribs 132 radiating outwardly from an area a spaced distance from bore 68 towards the outer perimeter 300 of mounting bracket 56 ribs 132 provide strength and rigidity to mounting bracket 56 both bore 68 and aperture 70 connect clean chamber 54 a to dirt collection chamber 54 b mounting bracket 56 is of a slightly smaller diameter than the internal diameter of housing 32 an inwardly disposed annular ledge 60 is provided on housing wall 34.