Patent ID: 8529512

Claim:
A cylinder pump comprising: a cylindrical upper casing inside which an upper rotator is rotatably inserted; and a cylindrical lower casing which is engaged with the upper casing and inside which a lower rotator that is in rotation sliding contact with the upper rotator is rotatably inserted, wherein an inner wall of the upper casing, a lower outer circumference of the upper rotator, an inner wall of the lower casing, and an upper outer circumference of the rotator form a single tubular cylinder, the upper rotator and the lower rotator include first and second plungers mounted thereon respectively, which make rotation in the tubular cylinder which is closed by the first and second plungers, the tubular cylinder is provided with an inlet tube for a liquid medication to be flowed in and an outlet tube for the liquid medication to be flowed out, wherein the inlet and outlet tubes are protruded from outer circumferences of the upper and the lower casings, the inlet tube and the outlet tube are placed in such a way that a central angle with respect to a center of rotation becomes more than one and less than two times a central angle (θ) of one of the first and second plungers, and the upper rotator and the lower rotator are connected to a driving device to be able to rotate independently.