EP1291086A2

EP1291086A2 - Electric dust collector and blower using the same

Info

Publication number: EP1291086A2
Application number: EP02015541A
Authority: EP
Inventors: Ikuo Akamine; Tsugio Kubo; Toshiyuki Imasaka; Yoshiaki Uchida; Yasuaki Matsumoto; Hirofumi Noma; Makiko Tokura
Original assignee: Matsushita Electric Industrial Co Ltd
Current assignee: Panasonic Corp
Priority date: 2001-08-31
Filing date: 2002-07-11
Publication date: 2003-03-12
Anticipated expiration: 2022-07-11
Also published as: ES2350682T3; CN2613317Y; KR20080098567A; KR100869628B1; CN1406671A; MY168533A; KR20030019252A; JP3818101B2; KR100914364B1; EP1291086B1; JP2003071321A; CN1257775C; EP1291086A3

Abstract

An electric dust collector of a high dust collection rate is disclosed. A charging section of the electric dust collector includes a first grounding electrode brought into contact with a dust filter, and second grounding electrodes surrounding needle-like discharge electrodes and electrically connected to the first grounding electrode. This structure generates corona discharge between the discharge electrodes and the first grounding electrode as well as between the discharge electrodes and the second grounding electrodes. Thus a discharging area is expanded, and charged dust particles can be collected with a high degree of efficiency.

Description

Field of the Invention

The present invention relates to an electric dust collector that collects dust in air, more particularly relates to a highly efficient electric dust collector that makes use of corona discharge and is to be employed in air conditioners or air purifiers. The present invention also relates to a method of collecting dust using the same dust collector.

Background of the Invention

An electric dust collector comprises mainly a charging section that generates corona discharge for charging dust and a dust collecting section that collects the charged dust. Those two elements are integrated into one unit and disposed at an air sucking port of air conditioners or air purifiers.
One of conventional electric dust collectors is disclosed in Japanese Patent Application Non-Examined Publication No. H11-151452. Fig. 7 shows this dust collector, which collects dust in the following manner: A voltage is applied between discharge electrode 503 and counter electrode 504, both the electrodes forming charging section 501, thereby generating corona discharge. This corona discharge charges dust in air blown there. Then dust collecting section 502, formed of grounding electrode 505 disposed downstream of air-flow path and high-voltage electrode 506, collects electrically the charged dust. Discharge electrode 503 is formed of linear wires or needles, and spaced away at a given distance from counter electrode 504. Dust collecting section 502 is constructed to collect dust using electricity; however, there is another instance, i.e., a charged filter is disposed for collecting dust.
However, the structure discussed above employs "two-step charging method", in other words, the charging section is formed of the discharge electrode and the counter electrode, and the dust collecting section is formed of the grounding electrode and the high voltage electrode. Thus the power should be supplied to the discharge electrode, counter electrode, grounding electrode and high voltage electrode, thereby complicating the structure.

Summary of the Invention

The present invention addresses the problem discussed above, and aims to provide an electric dust collector which comprises the following elements:
(a) a charging section including:
(a-1) needle-like discharge electrodes;
(a-2) a first grounding electrode;
(a-3) second grounding electrodes surrounding the needle-like discharge electrodes and coupled with the first grounding electrode; and
(b) a dust collecting section including:
(b-1) a dust filter to be brought into contact with the first grounding electrode.
Another structure of the electric dust collector of the present invention has a shielding plate for suppressing the discharge diffusion from the needle-like discharge electrode to the surrounding area.
Still another structure of the electric dust controller of the present invention allows a tip of the needle-like discharge electrode to be bent toward the first grounding electrode.
In the structures discussed above, a high voltage is applied to the needle-like discharge electrodes, and a grounding voltage is applied to the first and second grounding electrodes, whereby corona discharge is generated between the discharge electrodes and the grounding electrodes. When air passes through this corona discharging area, fine particles contained in air are charged, and the charged particles are efficiently collected by the dust filter disposed on the downstream side of the air-flow. As a result, an electric dust collector of a high dust collection rate is obtainable, and at the same time, charging to unnecessary parts can be suppressed, so that a stable operation of the dust collector can be expected.
The present invention thus overcomes the problem of conventional electric dust collectors and provides an electric dust collector that employs a simply structured one-step charging method which can charge dust particles efficiently. The dust collector of the present invention also can suppress charging phenomenon due to the discharge to the outer space from a dust collecting unit.

Brief Description of the Drawings

Fig. 1 is an exploded perspective view illustrating an electric dust collector in accordance with a first exemplary embodiment of the present invention.
Fig. 2 is a perspective view illustrating a structure of a dust collecting unit in accordance with a second exemplary embodiment of the present invention.
Fig. 3 is a perspective view illustrating a structure of a dust collecting unit in accordance with a third exemplary embodiment of the present invention.
Fig. 4 is a perspective view illustrating another structure of a dust collecting unit in accordance with the third exemplary embodiment of the present invention.
Fig. 5 is a perspective view illustrating a structure of a dust collecting unit in accordance with a fourth exemplary embodiment of the present invention.
Fig. 6 is a perspective view illustrating another structure of a dust collecting unit in accordance with a fourth exemplary embodiment of the present invention.
Fig. 7 is a perspective view illustrating a structure of a dust collecting unit in accordance with a fifth exemplary embodiment of the present invention.
Fig. 8 is a perspective view illustrating another structure of a dust collecting unit in accordance with the fifth exemplary embodiment of the present invention.
Fig. 9 is a perspective view illustrating a structure of a dust collecting unit in accordance with a sixth exemplary embodiment of the present invention.
Fig. 10 is a perspective view illustrating a structure of a dust collecting unit in accordance with a seventh exemplary embodiment of the present invention.
Fig. 11 is a perspective view illustrating a structure of an essential part of a conventional electric dust collector.

Detailed Description of the Preferred Embodiments

Exemplary embodiments of the present invention are demonstrated hereinafter with reference to the accompanying drawings.

Exemplary Embodiment 1

Fig. 1 is an exploded perspective view illustrating an electric dust collector in accordance with the first exemplary embodiment of the present invention. As shown in Fig. 1, electric dust collector 1 includes dust collecting unit 2 and main unit 3, in which dust collecting unit 2 is accommodated. Dust collector 1 is disposed, e.g., in an indoor unit of air conditioners. When interior air 4 passes through dust collecting unit 2, dust particles included in interior air 4 are collected, and air 4 undergoes a heat exchanger of the indoor unit, then blown out into the room again.
Main unit 3 includes power supply 5 for powering dust collecting unit 2, which is detachable from main unit 3 with handle 6. Power supply 5 applies a high voltage to main unit 3 at high-voltage contact 8A through high-voltage wire 7, while a grounding voltage is applied to main unit 3 at grounding contact 10A through grounding wire 9. With dust-collecting unit 2 mounted to main unit 3, high-voltage contact 8B electrically coupled with high-voltage contact 8A of main unit 3 and grounding contact 10B coupled with grounding contact 10A are provided to dust collecting unit 2.
Dust collecting unit 2 comprises the following elements:
(a) outer frame 11 made of molded resin material;
(b) a plurality of needle-like discharge electrodes 12 made of, e.g., stainless steel;
(c) meshed first grounding electrode 13 made of metal such as stainless steel having a small resistance against airflow for passing sucked air through and disposed on the downstream side of needle-like discharge electrodes 12; and
(d) second grounding electrodes 14 made of metal such as stainless steel and surrounding respective needle-like discharge electrodes 12.
The plurality of needle-like discharge electrodes 12 are electrically connected to supporter 17 which is mounted to frame 11. Further, electrodes 12 are electrically connected to high-voltage contact 8B, and first and second grounding electrodes 13, 14 are electrically connected to each other and coupled with grounding contact 10B. Discharge electrodes 12, first and second grounding electrodes 13, 14 constitute the charging section, and the corona discharge is generated in the space among these elements.
Honeycomb dust filter 15 is employed to form the dust collecting section because the honeycomb shape allows the sucked air to pass through with ease and realizes a high dust collection rate. Dust filter 15 is brought into contact with first grounding electrode 13. Partitions 16 are provided between respective blocks of the charging section so that the corona discharge from each one of needle-like discharge electrodes 12 cannot interfere with each other.
Outer frame 11 integrates the charging section and the dust collecting section into one boy, and handle 6 is mounted to frame 11, so that these elements form dust-collecting unit 2. Further, dust filter 15 in the dust collecting section is detachable from other elements of dust-collecting unit 2. Thus filter 15 can be cleaned or replaced with ease when it becomes dirty due to collecting fine particles in air. If the use of the dust collector extends over a long period, simple maintainability, such as cleaning or replacement of the dust filter, is thus prepared.
In the foregoing structure, when power supply 5 of main unit 3 applies a high voltage to the high voltage side, the corona discharge is generated in the charging section between discharge electrodes 12 and first grounding electrode 13 as well as between discharge electrodes 12 and second grounding electrode 14. When interior air 4 flowing from a sucking side passes through the corona discharging area, fine particles in air are charged. The charged particles are collected by dust filter 15 efficiently when they pass through filter 15.
In this embodiment, the high voltage side is negatively applied with a voltage so that the fine particles can be charged negatively; however, the high voltage side can be positively applied with a voltage so that the fine particles can be charged positively. When the high voltage side is negatively applied with a voltage, air-ions can be negatively charged, thereby generating minusions that can relax human bodies.
In this embodiment, first grounding electrode 13 uses a mesh-like shape; however, any shape is usable as far as electrode 13 passes the inflow air through and the corona discharge is generated between electrode 13 and needle-like discharge electrodes 12. For instance, a plate having plural openings shaping in circles or rectangles, a slit-like shape, or a cross-striped pattern is acceptable.
In this embodiment, a filter of honeycomb shape is used as dust filter 15; however, any shape is usable as far as filter 15 can pass the inflow air through and can be brought into contact with first grounding electrode 13. For instance, a pleated dust filter is acceptable.
In this first embodiment, as shown in Fig. 1, the charging section includes needle-like discharge electrodes 12 to which a high voltage is applied, first grounding electrode 13 and second grounding electrodes 14. The dust collecting section includes dust filter 15. Dust collecting unit 2 includes outer frame 11 that accommodates the charging section and the dust collecting section and integrates the two sections into one body. The grounding electrodes include first grounding electrode 13 brought into contact with dust filter 15 and second grounding electrodes 14 electrically connected to the first grounding electrode 13.
As shown in Fig. 1, dust collecting unit 2 is divided into a plurality of blocks by partitions 16, and second grounding electrodes 14 are arranged substantially parallel to needle-like discharge electrodes 12. Each one of second grounding electrodes 14 substantially shapes in letter "M".
This structure allows the corona discharge to be generated in spaces between needle-like discharge electrodes 12 and first grounding electrode 13 as well as between needle-like discharge electrodes 12 and second grounding electrodes 14. A greater discharging area can be thus created.
Dust collecting unit 2 is partitioned into plural blocks responsive to a number of needle-like discharge electrodes 12, and second grounding electrodes 14, each of them forming an approx. letter "M", are disposed on both sides of each one of those blocks. Adjacent electrodes 12 thus do not interfere with each other, and the discharge from each electrode 12 can diffuse outward of dust collecting unit 2 easily with assist from second grounding electrodes 14. This mechanism charges fine particles in air efficiently when sucked air passes through the dust collecting unit, and the dust filter placed on the downstream side can collect the charged particles at a high dust collection rate.

Exemplary Embodiment 2

The second exemplary embodiment is demonstrated with reference to Fig. 2. Similar elements to those in the first embodiment have the same reference marks, and the descriptions thereof are thus omitted here. Fig. 2 is a perspective view illustrating a dust collecting unit in accordance with the second embodiment.
A grounding electrode of a charging section includes first grounding electrode 13 and third grounding electrodes 19 disposed outside of tips 18 of respective needle-like discharge electrodes 12. First electrode 13 is electrically connected to third grounding electrodes 19. In other words, as shown in Fig. 2, third grounding electrodes 19 are disposed outside of both tips 18 of electrode 12 that is placed in one of blocks and along a shorter side of unit 2. The blocks are divided along a longer side of collecting unit 2.
When power supply 5 of main unit 3 applies a voltage to dust collecting unit 2, corona discharge is generated in spaces between needle-like discharge electrodes 12 and first grounding electrode 13 as well as between electrodes 12 and third grounding electrodes 19. The corona discharge thus prevails in entire dust collecting unit 2, so that the overall area of unit 2 can be effectively used. When air passes through this corona discharging area, dust collecting unit 2 charges fine particles in air efficiently, and dust filter 5 can collect the charged particles with a high degree of efficiency.

Exemplary Embodiment 3

The third exemplary embodiment is demonstrated with reference to Fig. 3 and Fig. 4. Similar elements to those in the embodiments previously demonstrated have the same reference marks, and the descriptions thereof are thus omitted here. Fig. 3 and Fig. 4 are perspective views illustrating dust collecting units in accordance with the third embodiment.
In Fig. 3, a grounding electrode of a charging section includes first grounding electrode 13 and second grounding electrodes 20 that are made of conductive resin. Electrode 13 is electrically connected to electrodes 20. In Fig. 4, in the same manner as described about Fig. 3, a grounding electrode of a charging section includes first grounding electrode 13 and third grounding electrodes 21 that are made of conductive resin. Second grounding electrodes 20 and third ones 21 both made of conductive resin are disposed on a surface of outer frame 11 of dust collecting unit 2 or integrated into outer frame 11.
When power supply 5 of main unit 3 applies a voltage to dust collecting unit 2, in the case of Fig. 3, corona discharge is generated in spaces between needle-like discharge electrodes 12 and first grounding electrode 13 as well as between electrodes 12 and second grounding electrodes 20. In the case of Fig. 4, the corona discharge is generated in spaces between electrodes 12 and first grounding electrode 13 as well as between electrodes 12 and third grounding electrodes 21. When air passes through this corona discharging area, dust collecting unit 2 charges fine particles in air efficiently, and dust filter 15 can collect the charged particles with a high degree of efficiency.
Since second and third grounding electrodes 20 and 21 are made of conductive resin, they are more flexible in shapes than the electrodes made of metal. Electrodes 20 and 21 can be thus disposed on the surface of outer frame 11 or integrated into outer frame 11. Further, resin is easier to handle in manufacturing. When they are integrated with frame 11, the corona discharge can prevail in entire dust collecting unit 2. As a result, an electric dust collector of a high dust collection rate is obtainable.

Exemplary Embodiment 4

The fourth exemplary embodiment is demonstrated with reference to Fig. 5 and Fig. 6. Similar elements to those in the embodiments previously demonstrated have the same reference marks, and the descriptions thereof are thus omitted here. Fig. 5 is a perspective view illustrating a dust collecting unit in accordance with the fourth embodiment, and Fig. 6 shows a sectional view taken along line A ― A of Fig. 5.
As shown in Fig. 5 and Fig. 6, first shielding plates 22 that cover needle-like discharge electrodes 12 are provided above electrodes 12 and to outer frame 11, i.e., on the upstream side of interior air 4 flowing into dust collecting unit 2. Other elements of dust collecting unit 2 stay the same as described in the first embodiment. In the charging section, corona discharge is generated in spaces between needle-like discharge electrodes 12 and first grounding electrode 13 as well as between electrodes 12 and second grounding electrodes 14. The discharge from electrodes 12 occurs all around each electrode 12, thus parts of the discharge exist in a space on the upstream side of electrodes 12. This existence of the discharge incurs electrical noises to components placed in the space on the upstream side.
In this fourth embodiment, first shielding plates 22 are provided to outer frame 11, so that the discharge from electrodes 12 to the space on the up-stream side where interior air 4 flows is suppressed. As a result, the components placed in the space on the upstream side are prevented from being charged, and a stable operation of the dust collector can be expected.

Exemplary Embodiment 5

The fifth exemplary embodiment is demonstrated with reference to Fig. 7 and Fig. 8. Similar elements to those in the embodiments previously demonstrated have the same reference marks, and the descriptions thereof are thus omitted here. Fig. 7 is a perspective view illustrating a dust collecting unit in accordance with the fifth embodiment, and Fig. 8 shows a sectional view taken along line A―A of Fig. 7.
As shown in Fig. 7 and Fig. 8, in this fifth embodiment, shielding walls 23 are provided to both sides of each shielding plate 22 which is described in the fourth embodiment. Other elements of dust collecting unit 2 stay the same as described in the first embodiment. In the charging section, corona discharge is generated in spaces between needle-like discharge electrodes 12 and first grounding electrode 13 as well as between electrodes 12 and second grounding electrodes 14. Parts of the discharge exist also in spaces on the upstream side and lateral sides of discharge electrodes 12. Shielding walls 23 are provided to both sides of each electrode 12 in addition to first shielding plate 22, so that the discharge from electrodes 12 to the space on the upper stream side, where interior air 4 flows, is suppressed by those shielding plates and walls. As a result, the components placed in the space on the upstream side are prevented from being charged, and a stable operation of the dust collector can be expected.

Exemplary Embodiment 6

The sixth exemplary embodiment is demonstrated with reference to Fig. 9. Similar elements to those in the embodiments previously demonstrated have the same reference marks, and the descriptions thereof are thus omitted here. Fig. 9 is a sectional view of a dust collecting unit in accordance with the sixth embodiment.
In this sixth embodiment, tips of needle-like discharge electrodes 12 are bent toward first grounding electrode 13, and these bent tips work as needle-like discharge electrodes 24. Other elements of dust collecting unit 2 stay the same as demonstrated in the first embodiment. Corona discharge is generated in spaces between bent needle-like discharge electrodes 24 and first grounding electrode 13 as well as between electrodes 24 and second grounding electrodes 14. The discharge from electrodes 24 to spaces on the upstream side is suppressed because the tips of needle-like electrodes are bent toward a reversal side to the air-sucking side. As a result, other members disposed in a space on the upstream side are restrained from being charged.

Exemplary Embodiment 7

The seventh exemplary embodiment is demonstrated with reference to Fig. 10. Similar elements to those in the embodiments previously demonstrated have the same reference marks, and the descriptions thereof are thus omitted here. Fig. 10 is a sectional view of a dust collecting unit in accordance with the seventh embodiment.
In this seventh embodiment, tips of needle-like discharge electrodes 12 are bent toward first grounding electrode 13, and these bent tips work as needle-like discharge electrodes 24. Hitherto is the same as the sixth embodiment. Second shielding plates 25 are additionally provided to vicinities of tip-ends of electrodes 24. Shielding plates 25 are bonded to electrodes 24. Other elements of dust collecting unit 2 stay the same as demonstrated in the first embodiment.
Corona discharge is generated between electrodes 24 and first grounding electrode 13 as well as between electrodes 24 and second grounding electrodes 14. The discharge from electrodes 24 to the space on the upstream side is suppressed by second shielding plates 25. As a result, other members disposed in a space on the upstream side of the air sucking side are restrained from being charged.
The present invention uses those dust collectors demonstrated in the previous embodiments in blowers. Electric dust collector 1 comprising dust collecting unit 2 and main unit 3 is disposed in an air-flow path of a blower that comprises a blowing fan and the air-flow pass, so that an air conditioner or an air purifier is formed. The electric dust collector of the present invention can diffuse the discharge into the entire dust collector, therefore, the use of this dust collector realizes a simply constructed air conditioner or air purifier having a substantially small draft loss therethrough and no adversely influence to other electronic devices. The air conditioner or air purifier that employs the electric dust collector of the present invention also features a high dust collection rate.
As discussed above, according to the present invention, a charging section is formed of (1) needle-like discharge electrodes, to which a high voltage is applied, and (2) a grounding electrode. A dust collecting section is formed of (3) a dust collector, and (4) an outer frame accommodates and integrates the charging section and the dust collecting section into a dust collecting unit. The grounding electrode is formed of (5) first grounding electrode brought into contact with the dust filter and (6) second grounding electrodes surrounding the needle-like discharge electrodes and being electrically connected to the first grounding electrode.
This structure generates corona discharge in the charging section between the needle-like discharge electrodes and the first grounding electrode as well as between the needle-like discharge electrodes and the second grounding electrodes. Thus the corona discharge is generated in a greater area, so that when sucked air passes through the dust collecting unit, fine particles in air are charged efficiently. The dust filter disposed on the downstream side can collect the charged particles at a high dust collection rate.

Claims

An electric dust collector comprising:

a charging section including a discharge electrode and a counter electrode; and

a dust collecting section,

wherein the counter electrode has a first grounding electrode brought into contact with said dust collecting section, and
wherein the discharge electrode is surrounded by a second grounding electrode electrically coupled with the first grounding electrode.
The electric dust collector of claim 1, wherein the discharge electrode is a needle-like electrode.
The electric dust collector of claim 2, wherein a tip of the discharge electrode faces the first grounding electrode.
The electric dust collector of claim 1, wherein a shielding section is provided around the discharge electrode for restraining discharge from diffusing.
An electric dust collector comprising:

a charging section;

a dust collecting section including a dust filter; and

a dust collecting unit including an outer frame that integrates said charging section with said dust collecting section,

wherein said charging section is formed of a needle-like discharge electrode and a grounding electrode both disposed in said dust collecting unit, and
wherein the grounding electrode is formed of a first grounding electrode brought into contact with the dust filter and a second grounding electrode surrounding the discharge electrode.
The electric dust collector of claim 5, wherein said dust collecting unit includes a plurality of discharge electrodes and a partition member which divides said dust collecting unit responsive to a number of the discharge electrodes.
The electric dust collector of claim 5, wherein the second grounding electrode is disposed in a space closer to the discharge electrodes than the first grounding electrode.
The electric dust collector of claim 5, wherein the second grounding electrode is disposed further outer side of said dust collecting unit than tips of the discharge electrodes.
The electric dust collector of claim 5, wherein the second grounding electrode is made of conductive resin, and forms at least a part of the outer frame of said dust collecting unit.
The electric dust collector of claim 5, wherein said dust collecting unit is disposed in an air-flow path,
wherein the discharge electrodes are disposed on an upstream side of the air-flow path,
wherein said dust collecting section is disposed on a down stream side of the air-flow path, and
wherein a shielding plate is disposed on an upstream side of the discharge electrodes for covering at least tips of the discharge electrodes.
The electric dust collector of claim 10, wherein the shielding plate has a recess opened toward a down stream side of the air-flow path
The electric dust collector of any one of claim 5 through claim 11, wherein tips of the discharge electrodes are bent toward the first grounding electrode.
The electric dust collector of claim 12, wherein second shielding plates are provided to the bent discharge electrodes at their end and on the upstream side of the air-flow path.
The electric dust collector of claim 5, wherein said dust collecting section is detachable from said dust collecting unit.
A blower comprising a blowing fan, an air-flow path, and an electric dust collector disposed in the air-flow path,
wherein the electric dust collector is defined in any one of claim 5 through claim 14.