Dust collector and vacuum cleaner having the same

A vacuum cleaner comprising a dust collector;

• wherein the dust collector comprising:
• a first cyclone body formed by an outer case having a hollow shape and an inner case provided inside the outer case, the first cyclone body forming a first cyclone to separate contaminants from air received from outside the dust collector;
• and
• a second cyclone body forming a set of second cyclones to separate contaminants from air that has passed through the first cyclone body,
• wherein the second cyclone body includes:
• a shell casing mounted on the inner case, the shell casing including casings of the second cyclones that are positioned around a hollow region;
• and
• vortex finders provided inside the casings, the vortex finders including hollow bodies and guide vanes extending in a spiral direction around the hollow bodies, and
• wherein:
• the shell casing further includes inlet flow paths extending from the hollow region to the casings, and each of the inlet flow paths is formed in an eccentric direction relative to a center of a corresponding one of the vortex finders positioned in the casings;
• each of the second cyclones includes a first region and a second region that are formed between an inner circumferential surface of a corresponding one of the casings and an outer circumferential surface of a corresponding one of the vortex finders;
• the first region is positioned in the eccentric direction;
• the second region is positioned opposite to the first region with respect to the center of the vortex finder;
• the guide vanes for each of the vortex finders includes a first guide vane provided in the first region that gradually shortens in a spiral direction away from a corresponding one of the inlet flow paths, and a second guide vane provided in the second region that gradually shortens in a spiral direction toward the corresponding one of the inlet flow paths;
• the second cyclones are positioned in contact with and around the hollow region;
• the shell casing further includes boundary walls extending from outer circumferences of each of the second cyclones toward the hollow region to form a boundary between the second cyclones, and inlet flow path forming extensions protruding from one or more surfaces of the boundary walls to form the inlet flow paths in the eccentric direction;
• for each of the flow paths, the inlet flow path forming extensions include a first forming extension protruding from a leading one the boundary walls, and a second forming extension protruding from a trailing one of the boundary walls;
• each of the first forming extensions and the second forming extensions includes a first surface adjacent to a portion of a corresponding one of the vortex finders and the associated casing, and a second surface extending from a start position of the inlet flow path and meeting the first surface at an edge;
• the hollow region of the shell casing is formed at a center of the shell casing;
• the inlet flow path starts from a circumference of the hollow region;
• the second surface of the first forming extension forms an acute angle with a first line tangential to the circumference of the hollow region at the start position of the inlet flow path;
• and
• the second surface of the second forming extension forms an obtuse angle with a second line tangential to the circumference of the hollow region at the start position of the inlet flow path.