Rotary drive apparatus

A rotary drive apparatus comprising:

• a housing, within which is located
• a first rotor and
• second rotor,
• the first rotor being rotatable about a first axis, having a rotor element projecting radially therefrom and
• the second rotor being rotatable about a second axis parallel to the first axis and in a direction opposite to the first rotor,
• the second rotor comprising a recess able to receive the rotor element,
• wherein the first rotor and the second rotor and housing define a chamber around the first rotor through which the rotor element passes, the chamber having an inlet and an outlet through which a fluid can enter and exit the chamber, wherein when the rotor element is engaged in the recess, the rotor element substantially occludes both the inlet and the outlet at the same time.

A rotary drive apparatus comprising a housing within which is located

• a first rotor and
• second rotor,
• the first rotor being rotatable about a first axis, having a rotor element projecting radially therefrom and
• the second rotor being rotatable about a second axis parallel to the first axis and in a direction opposite to the first rotor,
• the second rotor comprising a recess able to receive the rotor element,
• wherein the first rotor and the second rotor and housing define a chamber around the first rotor through which the rotor element passes, the chamber having an inlet and an outlet through which a fluid can enter and exit the chamber,
• wherein when the rotor element is engaged in the recess, the rotor element substantially occludes both the inlet and the outlet at the same time and wherein the rotor element is defined by:
• a leading face which during rotation of the first rotor precedes the other parts of the rotor element, a trailing face opposed to the leading face, and an outer face which during the rotation of the first rotor, contacts or nearly contacts a wall of the chamber;
• an outer leading junction between the leading face and the outer face of the rotor element;
• an outer trailing junction between the trailing face and the outer face of the rotor element;
• an inner leading junction between an outer wall of the first rotor and the leading face of the rotor element;
• an outer trailing junction between the outer wall of the first rotor and the trailing face of the rotor element;
• and wherein the recess is defined by:
• walls spaced apart to accommodate the leading face and the trailing face of the rotor element, and a floor which contacts or nearly contacts the outer face of the rotor element when the rotor element is received in the recess;
• an inner leading junction between the floor and the leading wall of the recess;
• an inner trailing junction between the floor and the trailing wall of the recess;
• an outer leading junction between the leading wall of the recess, and an outer wall of the second rotor;
• and
• an outer trailing junction between the trailing wall of the recess, and the outer wall of the second rotor wherein, at an engaged position where the outer junctions of the rotor element are equidistant from a line X connecting the axes of the rotors,
• (a) the inner junctions of the rotor element are located by lines extending from the axis of the first rotor and making angles of about +37°, −37° with said line X;
• the outer junctions of the rotor element are located by a line extending from the axis of the first rotor and making angles of about +30°, −30° with said line X;
• the inner junctions of the recess are located by a line extending from the axis of the second rotor and making angles of about +38°, −38° with said line X;
• and the inlet and outlet are located in a zone through which the rotor element travels, but they avoid a zone through which the second rotor travels;
• (b) the inner and outer junctions of the rotor element are located by lines extending from the axis of the first rotor and making angles of about +40°, −40° with said line X;
• the inner junctions of the recess are located by a line extending from the axis of the second rotor and making angles of about +43°, −43° with said line X;
• the outer junctions of the recess are located by a line extending from the axis of the second rotor and making angles of about +46°, −46° with said line X;
• and the inlet and outlet are located in the zone through which the rotor element travels, but they avoid the zone through which the second rotor travels;
• (c) the inner and outer junctions of the rotor element are located by lines extending from the axis of the first rotor and making angles of about +40°, −40° with said line X;
• the inlet is located in the zone through which the rotor element travels and within a line extending from the axis of the first rotor and making an angle of about +38° with said line X, and avoids the zone through which the second rotor travels,
• the outlet is located in the zone through which the rotor element travels and within a line extending from the axis of the first rotor and making an angle of about −39° with said line X, and avoids the zone through which the second rotor travels,
• the inner junctions of the recess are located by a line extending from the axis of the second rotor and making angles of about +45°, −45° with said line X;
• the outer junctions of the recess are located by a line extending from the axis of the second rotor and making angles of about +53°, −53° with said line X;
• or
• (d) the inner and outer junctions of the rotor element are located by lines extending from the axis of the first rotor and making angles of about +40°, −40° with said line X;
• the inlet is located in the zone through which the rotor element travels and within a line extending from the axis of the first rotor and making an angle of about +38° with said line X, and avoids the zone through which the second rotor travels,
• the outlet is located in the zone through which the rotor element travels and within a line extending from the axis of the first rotor and making an angle of about −39° with said line X, and avoids the zone through which the second rotor travels,
• the inner junctions of the recess are located by a line extending from the axis of the second rotor and making angles of about +46°, −46° with said line X;
• and
• the outer junctions of the recess are located by a line extending from the axis of the second rotor and making angles of about +53°, −53° with said line X.