GB2428210A

GB2428210A - Dust collecting apparatus for a cyclonic vacuum cleaner

Info

Publication number: GB2428210A
Application number: GB0605869A
Authority: GB
Inventors: Dong-Hun Yoo; Myoung-Sun Choung; Jae-Sun You
Original assignee: Samsung Gwangju Electronics Co Ltd
Current assignee: Samsung Electronics Co Ltd
Priority date: 2005-07-12
Filing date: 2006-03-23
Publication date: 2007-01-24
Anticipated expiration: 2026-03-23
Also published as: AU2006201030B2; GB0605869D0; AU2006201030A1; CA2539374C; GB2428210B; CA2539374A1

Abstract

A dust-collecting apparatus 100 for a vacuum cleaner 10 includes a cyclone body 130 containing a cyclone chamber 110 and a dust-collecting chamber 120. A cyclone case 111 is provided in the cyclone body 130 to separate the cyclone chamber 110 and the dust-collecting chamber 120. An air inflow tube 170 penetrates an outer wall of the cyclone body 130 such that a suction passage provided at the outside of the cyclone body fluidly communicates with the lower end of the cyclone chamber 110. An air outlet tube 118 penetrates sequentially the bottom of the cyclone case 111 and the bottom of the cyclone body 130 to guide the air discharged from the cyclone chamber to a discharge passage at the outside of the cyclone body. The dust-collecting chamber 120 is connected to the cyclone chamber 110 by a dust discharge port 117 formed at a side surface of upper end of the cyclone chamber.

Description

Dust-Collecting Apparatus for a Vacuum Cleaner This invention relates to a

vacuum cleaner, and in particular to a dust-collecting apparatus for a vacuum cleaner for separating dust and other contaminants (hereinafter referred to as "dust") from drawn-in air.

In general, a vacuum cleaner is an apparatus for cleaning a surface by drawing in dust from a surface to be cleaned along with ambient air, and separating the dust from the drawn-in air. Such a vacuum cleaner comprises a dust-collecting apparatus for collecting the dust separated from the drawn-in air. Recently, a cyclonic dust-collecting apparatus for separating dust from the drawn-in air using a centrifugal force has been developed.

Compared to a conventional dust bag, a cyclonic dust-collecting apparatus is relatively permanent and clean, so it is more widely used.

Generally, in a conventional cyclonic dust-collecting apparatus, a cyclone chamber and a dust-collecting chamber are co-located, drawn-in air being whirled in the cyclone chamber, and dust separated from the drawn-in air by centrifugal force being collected in the chamber. In this case, dust collected in the dust-collecting chamber is scattered by the air flow, and the dust is then discharged along with the air discharged from the dust-collecting apparatus. In addition, when the position of the vacuum cleaner is changed, dust collected in the dust-collecting chamber may escape from the dust-collecting apparatus. Thus, the conventional dust-collecting apparatus has a problem: deteriorating dust collection efficiency due to this outflow of dust.

An aim of the invention is to provide a dust-collecting apparatus for a vacuum cleaner, which apparatus can prevent dust separated in a cyclone chamber from being discharged to the outside of the dust-collecting apparatus.

The present invention provides a dust-collecting apparatus for a vacuum cleaner, the apparatus comprising: a cyclone body provided with a cyclone chamber and a dust-collecting chamber, the cyclone chamber being a space in which air entering from the exterior of the cyclone body ascends in a whirling manner, and in which dust is separated from the air by a centrifugal force generated by the whirling air, and the dust-collecting chamber being a space in which the dust separated from the air accumulates; a cyclone case provided in the cyclone body and disposed above the dust-collecting chamber, the cyclone case being such that the cyclone chamber and the dust-collecting chamber are separate; an air inflow tube penetrating an outer wall of the cyclone body such that a suction passage provided at the outside of the cyclone body fluidly communicates with the lower end of the cyclone chamber; and an air outlet tube penetrating sequentially the lower end of the cyclone case and the lower end of the cyclone body to guide the air discharged from the cyclone chamber to a discharge passage provided outside of the cyclone body, wherein the dust-collecting chamber is connected to the cyclone chamber by a dust discharge port formed at the side surface of the upper end of the cyclone chamber.

Accordingly, since the cyclone chamber and the dust-collecting chamber are formed independently, it is possible to prevent dust collected in the dust-collecting chamber from being re-scattered by air flow and from entering the cyclone chamber.

According to a preferred embodiment, the air inflow tube has one side fixed to the cyclone body to support the cyclone case.

Advantageously, the cyclone body comprises an upper case which contains the cyclone case, and a dust-collecting receptacle having the dustcollecting chamber formed therein, the dust-collecting chamber being detachably connected to an open lower end of the upper case, and the air inflow tube passes between the upper case and the dust-collecting receptacle.

Preferably, the air outlet tube is provided with an air discharge port formed at an upper end thereof for allowing the air discharged from the cyclone chamber to enter therein, a portion of the upper end of the air outlet tube protruding to the inside of the cyclone chamber, thereby to dispose the air discharge port between the bottom surface of the cyclone case and the dust discharge port.

The air outlet tube may comprise first and second air outlet tube portions, the first air outlet tube portion extending upwards from the bottom surface of the cyclone body, and the second air outlet tube portion extending upwards from the bottom surface of the cyclone case and being connected to an upper end of the first air outlet tube portion, the air outlet tube supporting the cyclone case when the first and second air outlet tube portions are connected together. Preferably, the air outlet tube is formed such that its inner diameter gradually increases towards the bottom of the cyclone body.

The cyclone body may comprise an upper case surrounding the cyclone with a predetermined gap therebetween, the upper case having an open lower end; the dust- collecting receptacle being detachably connected to a lower end of the upper case and having the dust-collecting chamber formed therein; a support body provided to join the upper case and the dust-collecting receptacle; and at least one support rib connecting the support body and the cyclone case to support the cyclone case on the upper end of the dustcollecting receptacle. The dust discharged through the dust discharge port falls due to its own weight, passes sequentially between the cyclone case and the upper case and between the at least one support rib, and is then collected in the dust-collecting chamber. Further, the air inflow tube, the support rib(s) and the cyclone case are formed integrally with each other.

The support body is of annular shape, and is disposed between the upper case and the dust- collecting receptacle, the support rib(s) being provided radially about the cyclone case.

Preferably, a portion of the support body protrudes to the inside of the cyclone body, whereby the support body and the support rib(s) prevent the dust in the dust-collecting chamber from flowing to the upper case when the cyclone body is inclined.

Advantageously, an upper end of the cyclone case and an upper sidewall of the cyclone body are spaced apart from each other by a predetermined distance to form the dust discharge port. Conveniently, the dustcollecting apparatus further comprises a grille covering the dust discharge port for filtering the air drawn into the dust discharge port.

Preferably, the cyclone body is provided with a backflow preventing protrusion which protrudes downwardly from the upper sidewall for preventing dust in the dust-collecting chamber from re-entering to the cyclone chamber. Advantageously, the backflow preventing protrusion is cylindrical, and has an open lower end disposed at the upper end of the cyclone case, and the backflow preventing protrusion has an inner diameter larger than that of the cyclone case.

The cyclone body may be provided with a lower cover provided with a penetrating hole for communicating the outlet of the air outlet tube with the discharge passage, the lower cover being mounted at the lower end of the cyclone body for opening and closing said lower end, a filter being provided detachably between the lower cover and the outlet of the air outlet tube.

Conveniently, the cyclone case is provided with a spirally-shaped guide member for guiding the air drawn in through the air inflow tube, whereby the air ascends and whirls in the cyclone chamber.

The invention will now be described in greater detail, by way of example, with reference to the drawings, in which:- Figure 1 is an exploded perspective view illustrating a dust-collecting apparatus and a vacuum cleaner constructed according to the invention; Figure 2 is an exploded perspective view of the dust-collecting apparatus of Figure 1; Figure 3 is a sectional view showing an operating state of the dust-collecting apparatus of Figures 1 and 2; and Figure 4 is a sectional view showing another operating state of the dust-collecting apparatus of Figures 1 and 2.

In the following description, the same reference numerals are used to identify the same or similar elements in the different figures. The matters set forth in the description below, such as the detailed construction and method of operation, are only provided to assist in a comprehensive understanding of the invention, and should not be considered as limiting.

The present invention can be carried out without using some or all of those defined elements. Well-known functions or constructions are not described in detail to avoid obscuring the invention in unnecessary detail.

Referring to the drawings, Figures 1 to 4 show a dust-collecting apparatus 100, adapted for use in a vacuum cleaner 10, the dust- collecting apparatus comprising a cyclone body 130, an air inflow tube 170, and an air outlet tube 118. The cyclone body 130 is provided with an upper case 150, a dust-collecting receptacle 140 and a cyclone case 111.

The upper case 150 has a cylindrical shape with an open lower end, and includes a cut-out 151 to accomodate the air inflow tube 170. The dust-collecting receptacle 140 has a cylindrical shape with an open upper end. The dust-collecting receptacle 140 is detachably connected to the lower end of the upper case 150 to form an outer wall of the cyclone body 130. The inside of the cyclone body 130 is divided into a cyclone chamber 110 (for separating the dust from the air entering through the air inflow tube 170) and a dust- collecting chamber 120 for collecting the dust separated in the cyclone chamber.

The cyclone case 111 has a cylindrical shape, and is positioned in the upper case 150. The upper end of the cyclone chamber 110 is surrounded by an upper sidewall 156 of the upper case 150. The upper end surface of the cyclone case 111 is spaced from the upper sidewall 156 of the upper case 150 by a predetermined interval, and so a side of upper end portion of the cyclone chamber 110 is open. This open side functions as a dust discharge port 117 through which the dust is discharged by a centrifugal force generated by an ascending vortex current of air in the cyclone chamber 110. Once the air drawn into the cyclone chamber 110 ascends in a whirling manner and reaches the dust discharge port 117, the dust is separated from the drawn-in air by a centrifugal force, and is then discharged through the dust discharge port in the direction of the arrow "A" in Figure 3. A guide member 114 guides the air drawn in through an air inlet port 112, which is an exit of the air inflow tube 170, to form an ascending vortex air current in the cyclone chamber 110.

The cyclone case 111 has a closed lower end, and is positioned at the upper side of the dust-collecting chamber 120, whereby the cyclone chamber 110 defines a space separate from the dust-collecting chamber 120. The outer side surface of the cyclone chamber 110 is spaced from the inner wall surface of the upper case 150 by a predetermined interval.

The cyclone chamber 110 and the dust-collecting chamber 120 are connected to each other only through a dust discharge passage 121 and the dust discharge port 117 formed between the cyclone case 111 and the upper case 150. To this end, the cyclone case 111 is supported in the upper case 150 by a support body 160 and a support rib 165. The support body 160 is of annular shape, and is disposed between the upper case 150 and the dustcollecting receptacle 140, so that the support body is fixed to the cyclone body 130 when the upper case 150 and the dust-collecting receptacle 140 are connected to each other. In order to maintain airtightness inside the cyclone body 130 when the upper case 150 is connected to the dust-collecting receptacle 140, the support body 160 is provided with grooves 161 and 162 for receiving the lower end of the upper case and the upper end of the dust-collecting receptacle 140.

A screw-threaded member S is used securely to connect the support body 160 to the upper case 150, the screw-threaded member passing through the support body and then being connected to a coupling boss 159 of the upper case. The support body 160 is provided with a protrusion 164 which constitutes part of the cyclone body 130 when the support body is mounted in the cyclone body. Owing to this structure, the dust collected in the dust-collecting chamber 120 can be prevented from re-ascending, thereby preventing the dust collected in the dust-collecting chamber from flowing towards the upper case 150 when the cyclonic dust-collecting apparatus 100 is inclined as shown in Figure 4.

The support rib 165 is installed to couple the support body 160 with the cyclone case Ill.

The cyclone case 111 is supported by the support body 160 and by the support rib 165 thereby enabling the dust discharge passage 121 and the dust discharge port 117 to be formed. The support rib 165 preferably has a thickness of less than a predetermined value for minimising contact between the support rib and the dust D discharged from the cyclone chamber 110. In this case, in order to support more effectively the cyclone case 111, a plurality of support ribs 165 is provided radially about the cyclone case 111. In addition, at least one of the support ribs 165 is disposed above a passage P (see Figure 4). When the cyclonic dustcollecting apparatus 100 is inclined during use, the dust D flows to the upper case 150 along the passage P. Owing to the support ribs 165, when the cyclonic dust- collecting apparatus 100 is inclined, the dust D is prevented from entering the upper case 150.

As described previously, the dust-collecting chamber 120 is formed in the dust-collecting receptacle 140. The dust-collecting chamber 120 is positioned at the lower side of the cyclone chamber 110, while the upper case 150 and the dust-collecting receptacle 140 are coupled, thereby connecting the dust-collecting chamber 120 and the cyclone chamber 110 only through the dust discharge port 117 and the dust discharge passage 121. In other words, the dust-collecting chamber 120 and the cyclone chamber 110 are formed as substantially independent spaces. Accordingly, the air flowing into the cyclone chamber cannot move the dust D received in the dust-collecting chamber 120, and so backflow of the dust can be prevented. In addition, since the dust discharge passage 121 is formed between the cyclone chamber 110 and the upper case 150, even when the cyclonic dust- collecting apparatus 100 is inclined during use, the dust D which moves to the upper case does not flow into the cyclone chamber 110. Also, because the dust-collecting capacity of the dust-collecting chamber 120 does not depend on the size of the cyclone chamber 110, but depends on the size of the dust-collecting receptacle 140, the dust- collecting capacity of the dust-collecting chamber can be flexible by varying the size of the dust-collecting receptacle.

Any unstable air flow in the cyclonic dust-collecting apparatus 100 is most unstable at a position adjacent to the dust discharge port 117. Accordingly, owing to the unstable air flow, the dust discharged to the dust discharge port 117 may flow back into the cyclone chamber 110. In order to prevent this, the cyclone body 130 is provided with a cylindrically-shaped backflow preventing protrusion 155, this backflow preventing protrusion protruding downwards from the upper sidewall 156 of the upper case 150.

Owing to the backflow preventing protrusion 155, it is possible to prevent the dust discharged through the dust discharge port 117 from re- entering the cyclone chamber 110.

Preferably, the inner diameter of the lower end of the backflow preventing protrusion 155 is larger than that of the cyclone case 111. Accordingly, when ascending and whirling air enters the backflow preventing protrusion 155, the radius of the whirling air is increased, and so the whirling speed of the air is decreased. Accordingly, fine dust contained in the air that is not discharged through the dust discharge port 117, drops due to its weight in the direction of the arrow "B" in Figure 3, and then falls into the dust-collecting chamber 120.

The air inflow tube 170 penetrates a sidewall of the cyclone body 130, and connects with the cyclone case 111, so that the air inflow tube mates with a suction passage 30 of the vacuum cleaner 10 fluidly to communicate with the inside of the cyclone case 111. The suction passage 30 of the vacuum cleaner 10 is connected to a nozzle unit 20 (see Figure 1), and functions as the passage through which air drawn in from a surface to be cleaned is passed. The air inflow tube 170 is formed integrally with the cyclone case 111, the support ribs 165 and the support body 160. Accordingly, since the air inflow tube 170 can be installed at the upper case 150 together with the cyclone case 111 when mounting the cyclone case, the structure of the cyclonic dust-collecting apparatus 100 can be simplified.

In this case, additionally, the air inflow tube 170 can support the cyclone case 111.

The air outlet tube 118 is provided for guiding the air discharged from the cyclone chamber to a discharge passage (not shown) of the vacuum cleaner. The dust-collecting apparatus is constituted such that the air discharged from the cyclone chamber 110 does not pass through the upper case 150, but penetrates the bottom wall of the dust-collecting receptacle 140, and is then discharged. Accordingly, as shown in Figure 1, the air discharged from the dust-collecting apparatus 100 is guided to the outside of the vacuum cleaner 10 through an air discharge opening 45 formed in the bottom surface 41 of a chamber 40 which is a space provided for mounting the dust-collecting apparatus. Thus, as shown in Figure 1, the air discharge opening 45 is formed in the base of the chamber to connect to a motor 15. Accordingly, the inner structure of the vacuum cleaner 10 and the outer structure of the dust-collecting apparatus can be simplified. To this end, the air outlet tube 118 comprises a first portion 148 and a second portion 168. The first air outlet tube portion 148 protrudes upwards from the bottom surface of the dust-collecting receptacle 140, and an outlet 149 formed at the lower end of the first air outlet tube portion covers an open, lower end surface of the dust-collecting receptacle 140. The first air outlet tube portion 148 is formed such that its inner diameter gradually increases towards its lower end.

Accordingly, the dust D in the dust-collecting chamber 120 accumulates on the upper surface 148a of the lower end of the first air outlet tube portion 148.

The second air outlet tube portion 168 protrudes upwards from the bottom surface of the cyclone case 111. An air discharge port 113 is formed at the upper end of the second air outlet tube portion 168, the air discharge port being an entrance to the air outlet tube 118 through which air discharged from the cyclone chamber 110 enters.

A grille 119 is provided at the air discharge port 113, the grille preventing the dust in the cyclone chamber 110 from being drawn directly into the air outlet tube 118. The first and second air outlet tube portions 148 and 168 are connected together when the cyclone case 111 is mounted, and the second air outlet tube portion is formed integrally with the cyclone case 111. Accordingly, the air outlet tube 118 can support the cyclone case 111 when the first and second air outlet tube portions 148 and 168 are connected together.

The cyclonic dust-collecting apparatus 100 includes a filter 190 for filtering the air discharged from the cyclone chamber 110, which enhances the dust separation efficiency.

To this end, the open end of the dust-collecting receptacle 140 can be opened and closed by a lower cover 141, the filter 190 being provided in a space between the dust-collecting receptacle 140 and the lower cover. The lower cover 141 is provided with a penetrating hole 143 fluidly communicating with the outlet 149 of the air outlet tube 118 and with a support rib 144 for supporting the filter 190. The lower cover 141 is also provided with a slide protrusion 142 which is engageable with a slide groove 132 formed on a side surface of the lower end of the dustcollecting receptacle 140. Accordingly, since the filter 190 can be mounted detachably, its management is easy.

Operation of the cyclonic dust-collecting apparatus will now be described with reference to Figures 2 and 3.

Firstly, once the vacuum cleaner 10 is driven, dust-carrying air enters the cyclone chamber through the air inflow tube 170. The air drawn in ascends and whirls towards the upper sidewall 156 of the upper case 150 under the action of the guide member 114 which is formed as a spiral. The ascending and whirling air generates a centrifugal force which is applied to the dust contained in the whirling air. Owing to this centrifugal force, the dust contained in the air is whirled along the outermost diameter of the whirling air. Once the whirling dust D reaches the dust discharge port 117, which is provided at the upper end portion of the cyclone chamber 110, the dust is discharged to the outside of the cyclone case ill via the dust discharge port 117 by the centrifugal force. The radius of whirling air that reaches the upper sidewall 156 is increased by the backflow preventing protrusion 155, and so the whirling speed of the air decreases. Once the whirling speed decreases even fine dust which is not discharged through the dust discharge port 117, but is contained in the air, falls due to its own weight. The dust D discharged as described above goes between the cyclone case 111 and the upper case 150, and then accumulates in the dust- collecting chamber 120 disposed at the lower end of the cyclone case 111. After fine dust is separated from the air at the upper sidewall 156, the air descends again and enters the air outlet tube 118 through the air discharge port 113. The air outlet tube 118 is formed such that its inner diameter gradually increases towards the lower end thereof. Accordingly, the flow rate of air in the air outlet tube 118 is gradually reduced towards the lower end of air outlet tube 118. Hence, fine dust particles not removed in the cyclone chamber 110 are filtered when the air with a slow flow rate passes through the filter 190. Then, the air from which the fine dust is removed is discharged to the outside of the cyclonic dust-collecting apparatus 100 via the through holes 143 of the lower cover 141.

With this cyclonic dust-collecting apparatus, since the cyclone chamber 110 and the dust- collecting chamber 120 are defined independent spaces, dust collected in the dust- collecting chamber is prevented from re-scattering by the air flow, and from entering the cyclone chamber.

Also, since the air discharge port 113 is formed at a location which is spaced from the upper wall of the cyclone body 130, and the backflow preventing protrusion 155 protrudes from the upper wall of the cyclone body, although the dust may flow to the upper wall of the cyclone body due to a change in position of the cyclonic dust-collecting apparatus 100, the dust cannot enter the cyclone chamber. Accordingly, the apparatus of the invention has the advantage in that it is possible to prevent the dust from escaping to the outside through the air discharge port.

Since the dust-collecting chamber 120 is formed at the lower end of the cyclone chamber 110, the dust-collecting capacity of the dust-collecting apparatus 100 can be determined freely regardless of the size of the cyclone chamber.

Also, because the dust is separated from the air drawn into the cyclone chamber 110 through multiple stages including in the cyclone chamber, by the grille 119 and by the filter 190, the dust separation efficiency of this cyclonic dust-collecting apparatus can be enhanced.

While the invention has been shown and described with reference to a certain embodiment, it will be understood by those skilled in the art that various changes in form and details may be made without departing from the scope of the invention as defined by the claims.

Claims

I. A dust-collecting apparatus for a vacuum cleaner, the apparatus comprising a cyclone body provided with a cyclone chamber and a dustcollecting chamber, the cyclone chamber being a space in which air entering from the exterior of the cyclone body ascends in a whirling manner, and in which dust is separated from the air by a centrifugal force generated by the whirling air, and the dust-collecting chamber being a space in which the dust separated from the air accumulates; a cyclone case provided in the cyclone body and disposed above the dust- collecting chamber, the cyclone case being such that the cyclone chamber and the dust-collecting chamber are separate; an air inflow tube penetrating an outer wall of the cyclone body such that a suction passage provided at the outside of the cyclone body fluidly communicates with the lower end of the cyclone chamber; and an air outlet tube penetrating sequentially the lower end of the cyclone case and the lower end of the cyclone body to guide the air discharged from the cyclone chamber to a discharge passage provided outside of the cyclone body, wherein the dust- collecting chamber is connected to the cyclone chamber by a dust discharge port formed at the side surface of the upper end of the cyclone chamber.
2. Apparatus as claimed in claim 1, wherein the air inflow tube has one side fixed to the cyclone body to support the cyclone case.
3. Apparatus as claimed in claim 1 or claim 2, wherein the cyclone body comprises an upper case which contains the cyclone case, and a dustcollecting receptacle having the dust-collecting chamber formed therein, the dust-collecting chamber being detachably connected to an open lower end of the upper case, and wherein the air inflow tube passes between the upper case and the dust-collecting receptacle.
4. Apparatus as claimed in any one of claims I to 3, wherein the air outlet tube is provided with an air discharge port formed at an upper end thereof for allowing the air discharged from the cyclone chamber to enter therein, a portion of the upper end of the air outlet tube protruding to the inside of the cyclone chamber, thereby to dispose the air discharge port between the bottom surface of the cyclone case and the dust discharge port.
5. Apparatus as claimed in claim 4, wherein the air outlet tube comprises first and second air outlet tube portions, the first air outlet tube portion extending upwards from the bottom surface of the cyclone body, and the second air outlet tube portion extending upwards from the bottom surface of the cyclone case and being connected to an upper end of the first air outlet tube portion, the air outlet tube supporting the cyclone case when the first and second air outlet tube portions are connected together.
6. Apparatus as claimed in claim 4 or claim 5, wherein the air outlet tube is formed such that its inner diameter gradually increases towards the bottom of the cyclone body.
7. Apparatus as claimed in claim 1, wherein the cyclone body comprises an upper case surrounding the cyclone case with a predetermined gap therebetween, the upper case having an open lower end; a dust-collecting receptacle detachably connected to a lower end of the upper case and having the dust-collecting chamber formed therein; a support body provided to join the upper case and the dust-collecting receptacle; and at least one support rib connecting the support body and the cyclone case to support the cyclone case on the upper end of the dust-collecting receptacle, whereby the dust discharged through the dust discharge port falls due to its own weight, passes sequentially between the cyclone case and the upper case and between the at least one support rib and then collected in the dust-collecting chamber.
8. Apparatus as claimed in claim 7, wherein the support body, the air inflow tube, the at least one support rib and the cyclone case are formed integrally with each other.
9. Apparatus as claimed in claim 8, wherein the support body is of annular shape, and is disposed between the upper case and the dust- collecting receptacle, the at least one support rib being provided radially about the cyclone case.
10. Apparatus as claimed in any one of claims 7 to 9, wherein a portion of the support body protrudes to the inside of the cyclone body, whereby the support body and the at least one support rib prevent dust in the dust-collecting chamber from flowing to the upper case when the cyclone body is inclined.
11. Apparatus as claimed in any one of claims I to 10, wherein an upper end of the cyclone case and an upper sidewall of the cyclone body are spaced apart from each other by a predetermined distance to form the dust discharge port.
12. Apparatus as claimed in claim 11, further comprising a grille covering the dust discharge port for filtering the air drawn into the dust discharge port.
13. Apparatus as claimed in claim 11 or claim 12, wherein the cyclone body is provided with a backflow preventing protrusion which protrudes downwardly from the upper sidewall for preventing the dust in the dustcollecting chamber from re-entering the cyclone chamber.
14. Apparatus as claimed in claim 13, wherein the backflow preventing protrusion is cylindrical, and has an open lower end disposed at the upper end of the cyclone case, and the backflow preventing protrusion has an inner diameter larger than that of the cyclone case.
15. Apparatus as claimed in any one of claims 1 to 14, wherein the cyclone body is provided with a lower cover provided with a penetrating hole for communicating the outlet of the air outlet tube with the discharge passage, the lower cover being mounted at the lower end of the cyclone body for opening and closing said lower end, a filter being provided detachably between the lower cover 4nd the outlet of the air outlet tube.
16. Apparatus as claimed in any one of claims 1 to 15, wherein the cyclone case is provided with a spirally-shaped guide member for guiding the air drawn in through the air inflow tube, whereby the air ascends and whirls in the cyclone chamber.
17. Dust-collecting apparatus substantially as hereinbefore described with reference to, and as illustrated by, the drawings.
18. A vacuum cleaner substantially as hereinbefore described with reference to, and as illustrated by, the drawings.