Positive displacement rotary devices

A first rotor, the first rotor being configured to rotate adjacent to a second rotor that comprises a circular main body with a first axis of rotation and a vane extending radially from the main body, the vane having a leading edge and a trailing edge when the second rotor rotates in the clockwise direction and the first rotor comprising:

• a substantially circular first curved surface with its center at a second axis of rotation, the first curved surface having a first radius;
• a vane-receiving groove that is configured to receive the vane therein;
• and
• second and third curved surfaces disposed on opposing sides of the vane-receiving groove, the second and third curved surfaces intersecting the first curve but having a different radius than the first radius,
• wherein the substantially circular first curved surface is dimensioned to maintain substantially the same distance from the main body of the second rotor when adjacent to the main body of the second rotor to create a non-contact seal therebetween, the second curved surface is dimensioned to maintain substantially the same distance from the leading edge of the vane when adjacent to the vane to create a non-contact seal therebetween, the third curved surface is dimensioned to maintain substantially the same distance from the trailing edge of the vane when adjacent to the vane to create a non-contact seal therebetween, and the vane-receiving groove is dimensioned to maintain substantially the same distance from a distal end of the leading edge of the vane as the vane moves into the vane-receiving groove to create a non-contact seal therebetween and to maintain substantially the same distance from a distal end of the trailing edge of the vane as the vane moves out of the vane-receiving groove to create a non-contact seal therebetween, the non-contact seal being provide to prevent leakage between the first rotor and the second rotor when the first rotor and the second rotor rotate relative to one another.