Abstract: A quiet, inexpensive pump especially adapted for transporting fluid having particulate matter entrained therein comprises a one-piece housing having a chamber therein with an epitrochoidal planform satisfying the equation: x=(a+b)·cos(t)−c·cos((a/b+1)·t), and y=(a+b)·sin(t)−c·sin((a/b+1)·t), x and y being plotted from a center of said chamber, wherein 0≦t≦2&pgr;, a/b is an integer defining the number of lobes of said chamber, and b/c=2. A stator gear at the center of the chamber has (a/b)·n teeth, wherein n is an integer. A one-piece rotor, with a generally polygonal planform having a/b+1) curved sides, rotates eccentrically within the chamber. Apexes of said rotor are spaced from walls of said chamber to maintain a clearance between said apexes and said walls as said rotor rotates in said chamber, for permitting fluid flow through said clearance.

Abstract: A vacuum cleaner has a vacuum pump with a housing including a lobed chamber having an epitrochoidal planform satisfying the equationx=(a+b).multidot.cos (t)-c.multidot.cos ((a/b+1).multidot.t),andy=(a+b).multidot.sin (t)-c.multidot.sin ((a/b+1).multidot.t),where 0.ltoreq.t.ltoreq.2.pi., a/b=2 (thus defining the number of lobes in the chamber) and b/c=2. The chamber has outlet ports and inlet ports in each lobe of the chamber, and a central stator gear with 2n teeth. A triangular rotor with curved sides is disposed for eccentric rotation in the chamber such that an inlet port and outlet port in each lobe of the chamber are always in direct fluid communication during a portion of the rotor travel, which prevents excessive pressure build-up at the chamber inlet ports, and a central rotor gear with 3n teeth meshed with the stator gear.

Abstract: An axial flow hair dryer comprises a generally circular main housing with a transitional portion that smoothly reduces the housing diameter to an outlet. A first fan stage in the main housing generates an axial air flow through the housing. An outer duct has two axial extensions secured to the housing near the beginning of the transitional portion, and the housing air outlet introduces air exiting the housing into the outer duct. The housing and the outer duct form two additional ambient air intakes extending between the axial extensions in a smooth arc toward the main housing outlet. A second fan stage includes a second axial flow impeller in the outer duct for generating air flow through the ambient air intake. The second axial flow impeller includes inner and outer blades separated by an annular shroud that forms an extension of the main housing flow passage. A guide duct in the outer duct forms a further extension of the extended air flow passage, and the guide duct includes stator vanes at its outlet.