Abstract: The present invention relates to an air compressor and expander including: a first rotor coupled around a driving shaft; a second rotor coupled around a driven shaft so as to operate in cooperation with the first rotor; a casing adapted to form an air compression or expansion space by the rotation of the first rotor and the second rotor; first and second end covers adapted to close the both end portions of the casing in such a manner as to have the driving shaft and the driven shaft passed therethrough in the axial direction, thereby to have the first rotor or the second rotor disposed between them; a gear part disposed on any one side of the first and second end covers in such a manner as to be coupled around the driving shaft and the driven shaft for transmitting power to the driving shaft and the driven shaft; and a clearance-preventing means disposed at the opposite side to the gear part for preventing the clearance between the end covers and the rotors.

Abstract: The present invention has been made to solve the foregoing problems and it is an object of the present invention to provide a two-layer flow air conditioning system in which a partition wall is installed on a path between an evaporator and a heater core to divide internal air and external air, and a first temperature adjusting door and a second temperature adjusting door each having a fan shape are installed at both sides of the partition wall in such a manner as to be opened at their sides to control the flow direction of the internal air and the external air which are supplied to both sides of the partition wall so as to prevent any mixture between the internal air and the external air, thereby enhancing heating and cooling effects without degrading a defrosting performance.

Abstract: The present invention has been made to solve the foregoing problems and it is an object of the present invention to provide a two-layer flow air conditioning system in which a partition wall is installed on a path between an evaporator and a heater core to divide internal air and external air, and a first temperature adjusting door and a second temperature adjusting door each having a fan shape are installed at both sides of the partition wall in such a manner as to be opened at their sides to control the flow direction of the internal air and the external air which are supplied to both sides of the partition wall so as to prevent any mixture between the internal air and the external air, thereby enhancing heating and cooling effects without degrading a defrosting performance.