Field of the Invention
[0001] 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
[0002] 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.
[0003] 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.
[0004] 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
[0005] 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.
[0006] 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.
[0007] 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.
[0008] 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.
[0009] 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
[0010]
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
[0011] Exemplary embodiments of the present invention are demonstrated hereinafter with
reference to the accompanying drawings.
Exemplary Embodiment 1
[0012] 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.
[0013] 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.
[0014] 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.
[0015] 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.
[0016] 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.
[0017] 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.
[0018] 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.
[0019] 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.
[0020] 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.
[0021] 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.
[0022] 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.
[0023] 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".
[0024] 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.
[0025] 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
[0026] 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.
[0027] 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.
[0028] 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
[0029] 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.
[0030] 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.
[0031] 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.
[0032] 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
[0033] 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.
[0034] 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.
[0035] 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
[0036] 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.
[0037] 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
[0038] 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.
[0039] 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
[0040] 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.
[0041] 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.
[0042] 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.
[0043] 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.
[0044] 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.
[0045] 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.
1. 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.
2. The electric dust collector of claim 1, wherein the discharge electrode is a needle-like
electrode.
3. The electric dust collector of claim 2, wherein a tip of the discharge electrode faces
the first grounding electrode.
4. The electric dust collector of claim 1, wherein a shielding section is provided around
the discharge electrode for restraining discharge from diffusing.
5. 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.
6. 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.
7. 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.
8. 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.
9. 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.
10. 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.
11. 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
12. 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.
13. 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.
14. The electric dust collector of claim 5, wherein said dust collecting section is detachable
from said dust collecting unit.
15. 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.