A traditional vacuum cleaner is provided with a filter, so as to filter the inhaled dirty air and leave the dust grain in a dust collector. Therefore, the filter of such a vacuum cleaner should be cleaned or replaced after being used for a period of time. Otherwise, resistance of the vacuum motor will be increased after the filtering hole of the filter is blocked by thin dust, and even worse the motor will be burnt, which will not only bring trouble to the customer, but also affect performance and life of the vacuum cleaner.
In recent years, the manufacturers substitute a cyclone dust remover for the filter according to the principle of cyclone separation, and obtain a better dust removal result, the cyclone dust remover having therefore been widely applied to the vacuum cleaners. As shown in FIG. 1, this cyclone dust remover is provided inside a dust cup with a conical cyclone cylinder, which is provided at the upper end with an outlet pipe in the longitudinal direction, which is communicated with an air outlet of the dust cup; the cyclone cylinder is provided at the lower end with an opening, such that dust can fall into a dust-collecting box at bottom of the dust cup; an inlet pipe enters along the upper sidewall of the cyclone cylinder in the tangential direction, making gas stream included with dust produce cyclone in the cyclone cylinder; the dust grains fall to bottom of the dust-collecting box along the sidewall of the cyclone cylinder under the centrifugal force, and the gas stream after dust removal is discharged upwards out of the dust cup via the outlet pipe.
However, some shortcomings have also been found with this cyclone device in practical application: First, the outlet pipe may produce a high-frequency noise while working; second, because the height of the cyclone inlet is equivalent to that of the outlet pipe, the air entering from the cyclone inlet collides on the side of the outlet pipe, and may collide with the air lately entering from the cyclone inlet before revolving down to the conical tube body, which thus produces a noise.