A rotary device comprising a rotor encasement comprising a central opening; a primary rotor rotatably disposed within the central opening, the primary rotor comprising a main body and plurality of vanes extending radially from the main body, each of the plurality of vanes comprising a leading edge and trailing edge and a tip; and one or more scavenging rotors rotatably disposed at an edge of the central opening so that at least a portion of each of the one or more scavenging rotors extends radially into the central opening, each of the one or more scavenging rotors comprising a first curved surface extending from a second curved surface to a third curved surface, and a vane- receiving groove disposed between the second curved surface and the third curved surface such that the first curved surface, second curved surface, third curved surface, and vane receiving groove define an enclosed shape; in the first curved surface is configured to maintain a predetermined tolerance with the main body of the primary rotor and the plurality of vanes as the primary rotor and scavenging rotor rotate relative to one another; the vane-receiving groove extends into the scavenging rotor and is configured to receive a distal end of each of the plurality of vanes therein so that the distal end maintains the predetermined tolerance with the vane receiving groove as the primary rotor and scavenging rotor rotate relative to one another; and the rotary device being characterised in that: the second curved surface and the third curved surface are configured to maintain the predetermined tolerance with the leading edge and trailing edge of each of the plurality of vanes, respectively, as the primary rotor and scavenging rotor rotate relative to one another, wherein a curve of the tip and the leading edge and trailing edge of the plurality of vanes is shifted outward by 0.0005 inches (1.27×10 -5 m) and the second curved surface and the third curved surface are shifted inward by 0.0005 inches (1.27 ×10 -5 m), such that a tolerance between the primary rotor and scavenging rotor is 0.001 inches (2.54 ×10 -5 m) as the primary rotor and scavenging rotor rotate relative to one another. the first curved surface is configured to maintain a predetermined tolerance with the main body of the primary rotor and the plurality of vanes as the primary rotor and scavenging rotor rotate relative to one another; the vane-receiving groove extends into the scavenging rotor and is configured to receive a distal end of each of the plurality of vanes therein so that the distal end maintains the predetermined tolerance with the vane receiving groove as the primary rotor and scavenging rotor rotate relative to one another; and the rotary device being characterised in that: the second curved surface and the third curved surface are configured to maintain the predetermined tolerance with the leading edge and trailing edge of each of the plurality of vanes, respectively, as the primary rotor and scavenging rotor rotate relative to one another, wherein a curve of the tip and the leading edge and trailing edge of the plurality of vanes is shifted outward by 0.0005 inches (1.27×10 -5 m) and the second curved surface and the third curved surface are shifted inward by 0.0005 inches (1.27 ×10 -5 m), such that a tolerance between the primary rotor and scavenging rotor is 0.001 inches (2.54 ×10 -5 m) as the primary rotor and scavenging rotor rotate relative to one another.