Stack of separation disks

A stack of separation disks used in an oil separator, the oil separator including a spindle and a rotor having an inner peripheral space and rotable together with the spindle, the oil separator configured to separate mist oil from processing-target gas by rotating the rotor and introducing, into the inner peripheral space, oil for separation and the processing-target gas containing the mist oil;

• the stack of separation disks constituting the rotor by being stacked in one axial direction of the spindle, and the stack of separation disks comprising:
• a first separation disk constituted by a plate member having a circular truncated cone shape, the first separation disk having a rib formed on an inclined surface of the circular truncated cone shape, the rib of the first separation disk extending in a first direction inclined toward one direction in a rotation direction with respect to a radial direction from a center of rotation;
• and
• a second separation disk constituted by a plate member having the circular truncated cone shape, the second separation disk having a rib formed on an inclined surface of the circular truncated cone shape, the rib of the second separation disk extending in a second direction inclined toward another direction opposite the one direction in the rotation direction with respect to the radial direction from the center of rotation;
• wherein the first separation disk and the second separation disk are stacked alternately in the one axial direction of the spindle, the first separation disk and the second separation disk which are vertically stacked and adjacent to each other have the ribs arranged to cross each other in at least one position.