Body fluid component separating device

A body fluid component separating device, comprising:

• a housing comprising a container and a lid defining a sealed space against the outside, wherein the container comprises a central portion defined as an area including a central axis of the container, and a peripheral portion defined as an area surrounding the central portion;
• a piston configured to divide the sealed space of the housing into a first space and a second space, to fluidly connect the first space and the second space, and to move in a longitudinal direction of the container along an inner surface of the container, wherein the piston comprises:
• an outer body configured to move along the inner surface of the container;
• and
• an inner body located inside the outer body and connected to the outer body;
• a piston guide extending from the lid in the longitudinal direction and configured to guide a movement of the piston, wherein the inner body is configured to move along the piston guide, and wherein the piston guide and the inner body are located in the peripheral portion;
• a shaft located within the inner body, having a longitudinal axis, and configured to rotate about the longitudinal axis
• a male engagement element formed on the shaft;
• and
• a female engagement element configured to be engaged with the male engagement element and fixedly installed to the inner body,
• wherein the shaft, the male engagement element, and the female engagement element are configured to adjust a movement of the piston between a first location in which the first space has a first volume and a second location in which the first space has a second volume different from the first volume, and to fix the piston at an arbitrary location between the first location and the second location.