Defoaming structure of separation device

A defoaming structure of a separation device, comprising:

• a cyclone extending along a center axis, including an introduction portion which includes an introduction port to introduce a liquid containing foreign matters into an inner part, and a drain portion including a discharge port provided at a lower end to discharge the liquid and the foreign matters, and swirling the liquid in the inner part;
• and
• a cylindrical member surrounding the discharge port at an interval in a radial direction of separating from the center axis, and extending downward from the discharge port in a direction of extension of the cyclone, wherein
• the drain portion includes a first member connected to the introduction portion, a second member connected to the first member and having the discharge port provided thereon, and a first inner peripheral surface formed from the first member toward the second member and having an inner diameter decreasing downward in the direction of extension,
• the discharge port includes a second inner peripheral surface connected to the first inner peripheral surface and having an inner diameter increasing downward from the first inner peripheral surface in the direction of extension,
• the cylindrical member includes a third inner peripheral surface surrounding the discharge port, and an opening portion which is provided at an end and through which the foreign matters pass,
• a virtual surface on which the second inner peripheral surface extends toward the third inner peripheral surface along the direction of extension, intersects the third inner peripheral surface,
• a position where the virtual surface and the third inner peripheral surface intersect is located at a position spaced upward by a predetermined distance along the direction of extension from an end portion of the cylindrical member at which the opening portion is provided, and is configured such that at least a part of the liquid discharged from the discharge port collides with the third inner peripheral surface before reaching the opening portion,
• a radial spread of the liquid discharged from the discharge port is limited by an inner diameter of the third inner peripheral surface, and
• the liquid and the foreign matters colliding with the third inner peripheral surface flow toward the opening portion along the third inner peripheral surface and are discharged downward through the opening portion.