Abstract: A roots-style blower (210) has a housing (214), rotors (230) and manifolds (212) for the housing (214). The housing (214) forms an inlet plenum (220), a rotor chamber (224) and a discharge plenum (228). The rotors (230) have straight lobes (232) spaced by pockets (240). The pocket (240X) that traps gas between a leading and following lobe (232) and an inside wall of the rotor chamber (224) is a temporary closed cell (240X). The manifolds (212) and the housing (214) form a pair of back-pass loops (250-251), one for each rotor (230). Each back-pass loop (250-252) comprises a back-pass chamber (250), outer channels (252) from the discharge plenum (228) to the back-pass chamber (250), and inner channels (251) to the rotor chamber (224). Wherein, the back-pass chamber (250) volume as a percentage of closed cell (240X) volume ranges between about fifty-six percent (56%) and one-hundred-seventeen percent (117%).

Abstract: Exhaust apparatus for exhausting “dirty” exhaust gases accept a core flow of such exhaust gases and combine that with an annularly-surrounding “rooftop” flow of ambient air for diluting the exhaust gases as well as expelling the diluted flow in a forcibly expelled plume in order to ensure that the “effective” expulsion distance of the expelled diluted flow is at least the physical length of the exhaust apparatus plus the gains gotten from efflux velocity and flowrate.

Abstract: A roots-style blower (210) has a housing (214), rotors (230) and manifolds (212) for the housing (214). The housing (214) forms an inlet plenum (220), a rotor chamber (224) and a discharge plenum (228). The rotors (230) have straight lobes (232) spaced by pockets (240). The pocket (240X) that traps gas between a leading and following lobe (232) and an inside wall of the rotor chamber (224) is a temporary closed cell (240X). The manifolds (212) and the housing (214) form a pair of back-pass loops (250-251), one for each rotor (230). Each back-pass loop (250-252) comprises a back-pass chamber (250), outer channels (252) from the discharge plenum (228) to the back-pass chamber (250), and inner channels (251) to the rotor chamber (224). Wherein, the back-pass chamber (250) volume as a percentage of closed cell (240X) volume ranges between about fifty-six percent (56%) and one-hundred-seventeen percent (117%).

Abstract: A mixed flow fan wheel has a convex hub, an axially-spaced away concave annular shroud, and a plurality of angularly distributed blades extending between and interconnecting the hub and shroud, all which cooperatively define a plurality of inter-blade flow channels. Each has a pressure surface and spaced suction surface extending not only between spaced inlet and discharge edges but also, crosswise thereto, spaced hub-side and shroud-side edges. Each discharge edge is convex relative a center of geometry of the blade therefor. Each inter-blade flow channel originates in a generally rectangular shape between flanking inlet edges and terminates in another generally rectangular shape between flanking discharge edges, with a procession of gradations of generally rectangular shapes forming a progressive transition therebetween. Moreover, each inter-blade flow channel twists or corkscrews from inlet thereof to the discharge.

Abstract: Exhaust apparatus for exhausting “dirty” exhaust gases accept a core flow of such exhaust gases and combine that with an annularly-surrounding “rooftop” flow of ambient air for diluting the exhaust gases as well as expelling the diluted flow in a forcibly expelled plume in order to ensure that the “effective” expulsion distance of the expelled diluted flow is at least the physical length of the exhaust apparatus plus the gains gotten from efflux velocity and flowrate.