This invention discloses a multi-stage adjustable concentration separation device, comprising: a bent tube body, a
logarithmic spiral baffle, and a two-stage concentration
assembly. The bent tube body includes a separation tube section, a primary concentration tube section, a dense phase tube section, and a dilute phase tube section. The
logarithmic spiral baffle is disposed within the primary concentration tube section to define the dense phase flow channel and the dilute phase flow channel. The
logarithmic spiral baffle has multiple concentration sections, each including an exhaust port and a hinge. The hinge is rotatably disposed at the exhaust port. Filter holes are provided on the
peripheral wall of the dense phase tube section. The two-stage concentration
assembly includes a filter screen and a housing. The filter screen is disposed within the filter holes. The housing has an extraction chamber and an extraction port, the extraction chamber communicating with the filter holes. Thus, the dense phase
airflow sequentially passes through multiple concentration sections for primary concentration, improving the
powder concentration. The dense phase
airflow can also pass through the two-stage concentration
assembly for secondary concentration, further improving the
concentration effect. The logarithmic spiral baffle is used to reduce the
frictional resistance of the dense phase
airflow during the concentration process.