摘要 |
A dust collection unit (13) includes a swirl chamber (29), dust collection chambers (30, 31), a discharge pipe (57), an inlet pipe (35), a bypass inlet (41), and a bypass inlet airflow passage (28). The swirl chamber (29) swirls, along a side wall, dust-containing air having entered from a primary inlet (40) and a secondary inlet (42) having a smaller opening area than the primary inlet (40), and separates dust from the dust-containing air. The dust separated by the swirl chamber (29) is collected by the dust collection chambers (30, 31). A discharge pipe (57) has a discharge opening (54). The inlet pipe (35) allows the dust-containing air to flow from the primary inlet (40) into the swirl chamber (29). A bypass inlet (41) is formed in the inlet pipe (35). The bypass inlet airflow passage (28) allows the dust-containing air in the inlet pipe (35) having entered from the bypass inlet (41) to flow from the secondary inlet (42) into the swirl chamber (29). |