Multi-cyclone dust separating apparatus

1. A multi-cyclone dust separating apparatus, comprising:

a primary cyclone for centrifugally separating impurities from the sucked air;

a plurality of secondary cyclones for centrifugally separating impurities from the air supplied from the primary cyclone;

inflow guide paths for guiding the air discharged from the primary cyclone to the plurality of secondary cyclones; and

discharge guide tubes partially inserted into the plurality of secondary cyclones, for externally discharging the air from the plurality of secondary cyclones,

wherein the discharge guide tubes comprise cylindrical portions and intercepting portions extending from bottom ends of the cylindrical portions for preventing the air supplied to the plurality of secondary cyclones from being directly discharged to the discharge guide tubes, wherein the primary cyclone comprises a cylindrical grill member installed on an air outflow hole through which the air is discharged, the cylindrical grill member preventing backflow of impurities, and wherein the grill member comprises an air guide member protruded from the bottom of the grill member, the air guide member guiding the air passing through the grill member to the air outflow hole.

2. The multi-cyclone dust separating apparatus as claimed in claim 1 , further comprising an inflow/outflow cover installed on the top ends of the secondary cyclones, wherein the plurality of secondary cyclones are disposed at an outer circumference of the primary cyclone at predetermined intervals, and the inflow guide paths and the discharge guide tubes are integrally formed on the inflow/outflow cover.

3. The multi-cyclone dust separating apparatus as claimed in claim 1 , wherein the intercepting portions are installed at the bottom ends of the cylindrical portions vertically under end points of air inflow holes of the plurality of secondary cyclones.

4. The multi-cyclone dust separating apparatus as claimed in claim 3 , wherein the intercepting portions are circular-arc-shaped.

5. The multi-cyclone dust separating apparatus as claimed in claim 4 , wherein the intercepting portions have a length of the circular arc that substantially ranges from ⅓ to ⅔ of a circular circumference of the plurality of cylindrical portions.

6. The multi-cyclone dust separating apparatus as claimed in claim 3 , wherein the intercepting portion have a height that substantially ranges from ¼ to ½ of a height of the plurality of cylindrical portions.

7. The multi-cyclone dust separating apparatus as claimed in claim 1 , wherein the air guide member divides an inside area of the grill member into a plurality of areas.

8. The multi-cyclone dust separating apparatus as claimed in claim 7 , wherein the air guide member has a cross-shaped section to divide the inside area of the grill member into four areas.

9. A cyclone dust separating apparatus, comprising:

a cyclone body having an air inflow hole through which outside air containing impurities is sucked; and

a discharge guide tube for discharging the air from the cyclone body, the discharge guide tube including a cylindrical portion and an intercepting portion, the intercepting portion extended from a bottom end of the cylindrical portion for preventing the air supplied to the cyclone body from being directly discharged to the discharge guide tube, wherein the intercepting portion has an outer diameter equal to an outer diameter of the cylindrical portion.

10. The cyclone dust separating apparatus as claimed in claim 9 , wherein the intercepting portion is installed at the bottom end of the cylindrical portion vertically under an end point of the air inflow hole of the cyclone body.

11. The cyclone dust separating apparatus as claimed in claim 10 , wherein the intercepting portion is circular-arc-shaped.