The present invention provides a fluid transfer apparatus comprising: a rotating shaft comprising a rotation unit extending along an axial direction and a first eccentric unit and a second eccentric unit disposed to be spaced apart from each other along the axial direction; a first rotor housing forming a first fluid compression space in the shape of an epitrochoid curved surface; a second rotor housing forming a second fluid compression space in the shape of an epitrochoid curved surface, and positioned to be spaced apart from the first rotor housing along the axial direction; a first rotor disposed in the first fluid compression space so as to delimit the first fluid compression space into multiple variable-displacement spaces, and coupled to the first eccentric unit while surrounding the first eccentric unit in the radial direction of the first eccentric unit; and a second rotor disposed in the second fluid compression space so as to delimit the second fluid compression space into multiple variable-displacement spaces, and coupled to the second eccentric unit while surrounding the second eccentric unit in the radial direction of the second eccentric unit.

A pump includes: a rotor and a stator; the rotor having at least one liquid opening configured for fluid communication with a liquid source. The liquid opening is configured such that a stream of liquid is output to form a liquid blade between the rotor and the stator, and gas confined by the stator, the rotor and the liquid blade is driven through the pump . The pump is configured such that a pumping channel has side walls that slope towards each other from the rotor that comprises the liquid opening towards a further wall of the pumping channel remote from the rotor, such that a distance between the side walls decreases with increasing distance from the liquid opening, a tangent to a midpoint of the side walls having an angle of between 5° and 40° with respect to a line perpendicular to an axis of rotation of the rotor.

The present invention provides a fluid transfer apparatus comprising: a rotating shaft comprising a rotation unit extending along an axial direction and a first eccentric unit and a second eccentric unit disposed to be spaced apart from each other along the axial direction; a first rotor housing forming a first fluid compression space in the shape of an epitrochoid curved surface; a second rotor housing forming a second fluid compression space in the shape of an epitrochoid curved surface, and positioned to be spaced apart from the first rotor housing along the axial direction; a first rotor disposed in the first fluid compression space so as to delimit the first fluid compression space into multiple variable-displacement spaces, and coupled to the first eccentric unit while surrounding the first eccentric unit in the radial direction of the first eccentric unit; and a second rotor disposed in the second fluid compression space so as to delimit the second fluid compression space into multiple variable-displacement spaces, and coupled to the second eccentric unit while surrounding the second eccentric unit in the radial direction of the second eccentric unit.