1. Field of the Invention
This application relates generally to a vacuum cleaner and, more particularly, to a cyclone-type dust-collecting apparatus for a vacuum cleaner that generates an air vortex of dust-laden air drawn into the cyclone-type dust-collecting apparatus and utilizes the centrifugal force of the air vortex to separate the dust and dirt in the dust-laden air.
2. Description of the Prior Art
FIGS. 1–3 schematically illustrate the structure of a conventional cyclone-type dust-collecting apparatus for a vacuum cleaner as disclosed in U.S. Pat. No. 6,195,835 (assigned to the same assignee as the present application).
Now referring to FIG. 1, the conventional cyclone-type dust-collecting apparatus for a vacuum cleaner is generally made up of a cyclone body 20, a dust-collecting receptacle 30, and a grill assembly 40.
The cyclone body 20 is divided into an upper body 21 and a lower body 22 that are secured by a plurality of screws 23. The opening of a first connection pipe 24 of the lower body 22 is connected to one end of an extension pipe 1a. The other end of the extension pipe 1a is connected to a suction port (not shown) of the vacuum cleaner. The dust-laden air flows into the suction port (not shown) of the vacuum cleaner, flows through the extension pipe 1a and the first connection pipe 24, and enters into an air inflow port 25 of the lower body 22. The air then travels through the dust-collecting receptacle 30 and the grill assembly 40, flows into the upper body 21 of the conventional cyclone-type dust-collecting apparatus 10. The air from the dust-collecting receptacle 30 and the grill assembly 40 flows through an air outflow port 27 encased by a second connection pipe 26 of the upper body 21. The opening of the second connection pipe 26 is connected to one end of the extension pipe 1b, and the other end of the extension pipe 1b is connected to a cleaner body (not shown) of the vacuum cleaner. The air flowing out of the upper body 21 then ends up in the cleaner body (not shown) of the vacuum cleaner.
The first connection pipe 24 (and thus the air inflow port 25) of the cyclone body 20 is shaped in such a way so that the dust-laden air flows into the air inflow port 25 at an oblique angle or direction with reference to the direction of the first connection pipe 24 and the air inflow port 25, accordingly, to start and maintain the air vortex (shown by the arrows in FIG. 1) in the cyclone body 20 and also in the dust-collecting receptacle 30. The centrifugal force generated by the air vortex is then utilized to separate the dirt and dust in the dust-laden air. The dust-collecting receptacle 30 is removably connected to the cyclone body 20.
Now referring to FIG. 2, the grill assembly 40 includes a grill body 41 and an air backflow prevention plate 43. The grill assembly 40 is disposed at the air outflow port 27 of the cyclone body 20 (FIG. 1), for preventing the dust in the dust-collecting receptacle 30 from flowing back into the air outflow port 27. The grill body 41 of the grill assembly 40 is generally shaped as an elongated cylindrical tube that has a plurality of fine passage holes 42 throughout the outer circumferential surface of the cylindrically shaped grill body 41. The opening at one end of the grill body 41 is connected to the air outflow port 27 of the cyclone body 20. Generally, the opening of the grill body 41 includes at one end a circumferential edge 41a that is shaped to mate with the upper body 21 of the cyclone body 20. The other end of the grill body 41 is connected to the air backflow prevention plate 43, which is disposed at the other, lower end of the grill body 41. The air backflow prevention plate 43 preferably has a frusto-conical shape.
As described above, the air vortex is created in the dust-collecting receptacle 30 (solid-line arrows in FIG. 1). In the conventional cyclone-type dust collecting apparatus for the vacuum cleaner as described above, dust-laden air is drawn in by a suction force generated at a suction port of the cleaner, and into the cyclone body 20 in the oblique direction via the first connection pipe 24 and the air inflow port 25. Then, the air descends into the dust collecting receptacle 30, forming the air vortex (Solid-lined arrows in FIG. 1). During this process, the dust and dirt are separated from the air by the centrifugal force and collected in the dust collecting receptacle 30.
The dust-laden air in the dust-collecting receptacle 30, which is shown by air currents ascending upwardly from the bottom of the dirt-collecting receptacle 30 (shown as dotted-line arrows in FIG. 1), flows sequentially through the fine passage holes 42 of the grill assembly 40, the air outflow port 27, the second connection pipe 26 toward the cleaner body (not shown) of the vacuum cleaner. Some of the dust in the ascending air currents (dotted-line arrows in FIG. 1) in the dust-collecting receptacle 30 is blocked by the air backflow prevention plate 43 and is returned to the air vortex (solid line arrows in FIG. 1). The dust not blocked by the air backflow prevention plate 43 still remains in the ascending air currents after the air backflow prevention plate 43 returns the dust to the air current flow while the air is passed through the fine passage holes 42 of the grill assembly 40. Dust having a size larger than the size of the fine passage holes 42 is filtered by the fine passage holes 42 and is thereby returned to the air vortex. The dust that is not separated from the air vortex is discharged toward the air outflow port 27 through the fine passage holes 42 of the grill assembly 40, and is then filtered out by a paper filter (not shown) in the cleaner body (not shown) of the vacuum cleaner. The clean air is eventually discharged from the vacuum cleaner by a motor.
The conventional cyclone-type dust-collecting apparatus for a vacuum cleaner as described above, however, is difficult to maintain, mainly due to the difficulty associated with the removal of the dust gathered in and around the fine passage holes 42 of the grill assembly 40. During the discharging process, as the air is passed through the fine passage holes 42 of the grill assembly 40, the dust and dirt entrained the air is gathered in the fine passage holes 42, and clogs the openings. When the fine passage holes 42 are clogged with the dirt and dust, deterioration of the suction force may overload the motor of the vacuum cleaner. The overall cleaning efficiency of the vacuum cleaner is thereby lowered.
A user of the conventional type vacuum cleaner therefore is required to periodically remove the dust and dirt accumulated in and around the fine passage holes 42 of the grill assembly 40. However, removing the accumulated dust and dirt may not be an easy task to a user due to the way the grill assembly 40 is connected to the cyclone body 20 in a conventional cyclone-type dust-collecting apparatus. Therefore, it would be desirable to achieve a better dust and dirt removal feature that allows a user to more easily remove the dust and dirt accumulated on the grill assembly 40. In order to remove the dust and dirt from the grill assembly 40 in the conventional cyclone-type dust-collecting apparatus, the user must separate the cyclone-type dust-collecting apparatus from the extension pipe of the cleaner and directly remove the dust and dirt with a brush or his/her hand. Therefore, inevitably a sanitary problem results.
Further, the cleaning efficiency is positively influenced by more stable air vortex created in the cyclone body 20. The stability of the air vortex in the cyclone body 20 is affected by the air currents moving in different directions. For example, as shown in FIG. 3, the air vortex created in the cyclone body 20 of the conventional cyclone-type dust-collecting apparatus generally contains three air currents A, B, and C, each moving in a different direction. As the air is drawn in through the air inflow port 25, the air currents B and C mix with the air current A swirling along an inner circumference 22a of the lower body 22 of the cyclone body 20. The direction of the air currents B and C is not aligned with the direction of the air current A. For example, the air current C joins with the air current A at an angle θ as shown in FIG. 3. Therefore, a more stable air vortex and the cleaning efficiency can be achieved by controlling the flow directions of these air currents.