outer surface 36 to a third outer surface 40 having a diameter that is preferably smaller than second outer surface 36 when aspirating member 22 is received in intake port 20 sealing member 38 in second annular cavity 37 sealingly engages a corresponding wall in intake port 20 additionally a first annular void 41 is created between conical surface 39 and a corresponding conical surface 42 in intake port 20 similarly a second annular void 43 is created between third outer surface 40 and a corresponding surface 44 in intake port 20 voids 41 and 43 permit the free flow of fluid between aspirating member 22 and intake port 20 as the fluid enters intake 20 through first duct 24 referring to fig2 and 5 aspirating member 22 is preferably secured in intake port 20 by inserting locking member 35 into the area formed between cavities 34 and 44 an inlet tube 50 is secured to manifold 12 proximate aspirating member 22 to provide communication between aspirating member 22 and a remote fluid reservoir inlet tube 50 is preferably attached to manifold 12 via a plurality of threaded fasteners not illustrated however it is recognized that other methods of attachment known in the art such as.