Electrical dust collector and indoor unit for air conditioner

Abstract

To provide an electrical dust collector capable of suppressing draft resistance and improving dust collection performance and an indoor unit for an air conditioner provided with the electrical dust collector.SOLUTION: This electrical dust collector comprises: a discharge electrode; a counter electrode; and a wall. The discharge electrode is disposed on the upstream side of an air flow to generate corona discharge. The counter electrode is disposed to face the discharge electrode on the downstream side of the air flow, and collects dust contained in air. The wall guides the air from the discharge electrode toward the counter electrode between the discharge electrode and the counter electrode. The discharge electrode has a plurality of protrusions arrayed along the wall to protrude toward the wall. A relationship of D1<D2<1.5×D1 is satisfied, in which D1 denotes a counter distance between the discharge electrode and the protrusions, and D2 denotes a counter distance between the protrusions of the discharge electrode and the wall.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] An embodiment of the present invention relates to an electrostatic precipitator and an indoor unit of an air conditioner equipped with the electrostatic precipitator. [Background technology]

[0002] An electric precipitator may be installed in the indoor unit of an air conditioner (hereinafter simply referred to as the indoor unit). An electric precipitator is a device that applies an electric charge to dust in the air passing through the ventilation duct, capturing and collecting the dust using electrostatic force. The electric precipitator installed in the indoor unit, for example, collects dust contained in the air when the indoor unit draws in indoor air, thereby purifying the air. The electric precipitator is placed at the intake port through which the indoor unit draws in indoor air. As a result, the air drawn in from the intake port passes through the electric precipitator.

[0003] Therefore, in an electrostatic precipitator mounted in an indoor unit, it is required to suppress the ventilation resistance of the ventilation passage and to improve the dust collection performance. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 11-249382 [Patent Document 2] Japanese Patent Application Publication No. 2019-171334 Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention has been made based on this, and its object is to provide an electric dust collector that can reduce ventilation resistance and improve dust collection performance, and an indoor unit of an air conditioner that is equipped with such an electric dust collector. [Means for solving the problem]

[0006] According to an embodiment, an electrostatic precipitator includes a discharge electrode, a counter electrode, and a wall portion. The discharge electrode is disposed on the upstream side of the air flow to generate corona discharge. The counter electrode is disposed opposite to the discharge electrode on the downstream side of the air flow to collect dust contained in the air. The wall portion guides the air from the discharge electrode toward the counter electrode between the discharge electrode and the counter electrode. The discharge electrode has a plurality of protrusions arranged side by side along the wall portion and protruding toward the wall portion. When the facing distance between the discharge electrode and the counter electrode is D1 and the facing distance between the plurality of protrusions of the discharge electrode and the wall portion is D2, a relationship of D1 < D2 < 1.5×D1 is satisfied.

Brief Description of the Drawings

[0007] [Figure 1] It is a perspective view of an indoor unit of a ceiling-embedded air conditioner according to this embodiment. [Figure 2] It is a plan view schematically showing the electrostatic precipitator according to this embodiment from the indoor side (the upstream side of the air flow passing through the electrostatic precipitator). [Figure 3] It is a cross-sectional view schematically showing the electrostatic precipitator according to this embodiment from the arrow direction at the position indicated by arrow A2 in FIG. 2. [Figure 4] It is a perspective view schematically showing the electrostatic precipitator according to this embodiment including the cross-section shown in FIG. 3. [Figure 5] It is a diagram schematically showing the positional relationship among the discharge electrode, the counter electrode, and the wall portion in the electrostatic precipitator according to this embodiment. [Figure 6] It is a plan view schematically showing the counter electrode of the electrostatic precipitator according to this embodiment from the downstream side of the air flow passing through the counter electrode. [Figure 7] It is a diagram showing a comparison of the ventilation resistance, discharge area, and dust collection performance of the counter electrode of the electrostatic precipitator according to this embodiment according to the cell size of the honeycomb structure. [Figure 8]1 is a diagram schematically illustrating the relative positional relationship between a discharge electrode, a counter electrode, and a wall portion of an electric dust collector according to an embodiment of the present invention, as viewed from the upstream side of the flow of air passing through the electric dust collector. FIG. [Figure 9] 1 is a diagram schematically illustrating the relative positional relationship between a discharge electrode, a counter electrode, and a wall portion of an electric dust collector according to an embodiment of the present invention, viewed from a direction perpendicular to the flow of air passing through the electric dust collector. FIG. [Figure 10] FIG. 10 is a diagram showing the relationship between the opposing distance (D2) between the plurality of protrusions of the discharge electrode of the electric dust collector according to the present embodiment and the side wall of the wall portion, and the dust collection performance of the opposing electrode. [Figure 11] 1 is a diagram showing the relationship between the number (N) of protrusions of the discharge electrode of the electric dust collector according to the present embodiment and the ratio (D1 / P) of the facing distance (D1) to the distance (P) between the protrusions. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a perspective view of the indoor unit of a ceiling-embedded air conditioner according to this embodiment. As shown in Fig. 1, the indoor unit 1 of the air conditioner mainly comprises a unit main body 2 that is installed above the ceiling, and a panel (hereinafter referred to as a decorative panel) 3 attached to the lower end of the unit main body 2. The unit main body 2 comprises a housing 4. The housing 4 is configured in a box shape that opens toward the room, and is suspended from a beam above the ceiling via a plurality of suspension bolts (not shown), for example.

[0009] A blower 10 is housed inside the housing 4. The blower 10 draws in air from the space to be air-conditioned, i.e., the room, and blows the air into the room after heat exchange in a heat exchanger (not shown). In the illustrated example, a so-called centrifugal fan that draws in air in the axial direction and blows it out in the circumferential direction is used as the blower 10. The heat exchanger exchanges heat between the air in the space to be air-conditioned, i.e., the room, and the refrigerant, thereby conditioning the room. The heat exchanger stands inside the housing 4 so as to surround the blowing side of the blower 10.

[0010] The decorative panel 3 is placed along the ceiling (not shown) of the space to be air-conditioned, and covers the opening at the lower end of the housing 4 from the inside of the room. The decorative panel 3 includes a grill (hereinafter referred to as an intake grill) 80 and a frame 81.

[0011] Intake grille 80 is located in the center of decorative panel 3, rotatably supported by frame body 81, and is an element that shields intake port 87 that draws indoor air into housing 4. Intake grille 80 has a substantially square outer frame portion 82 and a lattice portion 83 surrounded by outer frame portion 82. Lattice portion 83 is located directly below blower 10.

[0012] The frame 81 of the decorative panel 3 is, for example, a substantially square-shaped element that surrounds the intake grille 80 and has first to fourth sides 85a, 85b, 85c, and 85d and four corners 86a, 86b, 86c, and 86d. The square area surrounded by the inner peripheral edges of the first to fourth sides 85a, 85b, 85c, and 85d defines the intake port 87. The decorative panel 3 is detachably connected to the housing 4 at the four corners 86a, 86b, 86c, and 86d of the frame 81. As a result, the lower end of the unit main body 2 is covered by the decorative panel 3.

[0013] The decorative panel 3 has four air outlets 88 that blow out the air that has undergone heat exchange in the heat exchanger into the room. The air outlets 88 are formed on the first to fourth side portions 85a, 85b, 85c, and 85d of the frame body 81.

[0014] Four louvers 89 are rotatably supported on the frame 81 of the decorative panel 3. The louvers 89 are elements that change the blowing direction of air blown into the room from the air outlet 88, and are formed in the shape of flat, elongated plates. The louvers 89 are rotatable between a closed position that closes the air outlet 88 and an open position that tilts to open the air outlet 88. When the louvers 89 are rotated to the closed position, the four louvers 89 are horizontal and completely cover the first to fourth sides 85a, 85b, 85c, and 85d of the frame 81, respectively.

[0015] In the illustrated example, one side of the outer frame portion 82 of the intake grille 80 of the decorative panel 3 is rotatably connected to the third side portion 85c of the frame body 81. Therefore, the intake grille 80 is rotatable between a first position where the intake port 87 is closed and a second position where the intake port 87 is opened.

[0016] The unit body 2 is equipped with an electrostatic precipitator 60. In this embodiment, as an example, the electrostatic precipitator 60 is attached to the housing 4 so as to be disposed at the suction port 87. In the illustrated example, two electrostatic precipitators 60 are attached to the housing 4, but the number is not limited to this. The electrostatic precipitator 60 thus arranged is positioned upstream of the blower 10 housed in the housing 4 in the flow of air that the blower 10 draws from the room into the housing 4.

[0017] Therefore, air drawn into housing 4 from the indoors by blower 10 passes through suction port 87 and electrostatic precipitator 60. As a result, when blower 10 draws air from the indoors into housing 4, electrostatic precipitator 60 collects dust contained in the drawn air and purifies the air. In the illustrated example, electrostatic precipitator 60 is disposed at suction port 87, but electrostatic precipitator 60 may also be disposed at air outlet 88.

[0018] 2 to 4 schematically show the configuration of an electrostatic precipitator 60 according to this embodiment. Fig. 2 is a plan view schematically showing the electrostatic precipitator 60 from the indoor side, in other words, from the upstream side of the flow of air passing through the electrostatic precipitator 60. Fig. 3 is a cross-sectional view schematically showing the electrostatic precipitator 60 at the location indicated by arrow A2 in Fig. 2, viewed from the direction of the arrow. Fig. 4 is a perspective view schematically showing the electrostatic precipitator 60 including the cross section shown in Fig. 3.

[0019] As shown in Figures 2 to 4, the electrostatic precipitator 60 has two electrode parts: a discharge electrode 62 and a counter electrode 64, which are arranged substantially parallel and facing each other. The discharge electrode 62 is an electrode that is arranged upstream of the air flow passing through the electrostatic precipitator 60 and generates a corona discharge. The upstream side of the air flow passing through the electrostatic precipitator 60 is the upwind side of the air flow, i.e., the wind generated by the air current, and corresponds to the front side in Figure 2. The counter electrode 64 is arranged downstream of the air flow passing through the electrostatic precipitator 60 and is an electrode (dust collection electrode) that collects dust contained in the air. The downstream side of the air flow passing through the electrostatic precipitator 60 is the downwind side of the air flow, i.e., the wind generated by the air current, and corresponds to the back side in Figure 2.

[0020] The electrostatic precipitator 60 includes a wall 66 that defines an air passage 601 through which air passing through the electrostatic precipitator 60 flows. The wall 66 guides the air flowing through the air passage 601 from the discharge electrode 62 to the counter electrode 64 between the discharge electrode 62 and the counter electrode 64. That is, in the air passage 601 defined by the wall 66, the discharge electrode 62 is disposed at the upstream end of the air flow in the air passage 601, and the counter electrode 64 is disposed at the downstream end. This causes the air flowing through the air passage 601 at the ends of the air passage 601 to pass through the discharge electrode 62 and the counter electrode 64. In other words, the air passage 601 is substantially cylindrical and open at both ends where the discharge electrode 62 and the counter electrode 64 are located.

[0021] The discharge electrode 62 is, for example, a plate-shaped or foil-shaped electrode and includes a main body 62a and protrusions 62b. The main body 62a extends linearly on a plane perpendicular to the flow direction of air passing through the discharge electrode 62. The protrusions 62b protrude from the main body 62a in a direction perpendicular to the extension direction of the main body 62a on the plane. In FIGS. 2 to 4, the first direction X is the direction along the flow direction of air passing through the electrostatic precipitator 60 (the discharge electrode 62 and the counter electrode 64), the second direction Y is the direction along the extension direction of the main body 62a, and the third direction Z is the direction along which the protrusions 62b protrude from the main body 62a. These three directions X, Y, and Z are perpendicular to one another.

[0022] 2 to 4, the discharge electrode 62 is disposed at the upstream end of an air passage 601 defined by the wall portion 66 in the direction of air flow in the air passage 601, with the main body portion 62a supported by a support portion 66e of the wall portion 66, which will be described later. In the illustrated example, the support portion 66e is configured in a lattice shape and extends along a plane defined by the second direction Y and the third direction Z. The main body portion 62a extends along the second direction Y while being placed on a pedestal 66f of the support portion 66e. The pedestal 66f extends a predetermined length from the support portion 66e in the first direction X and is provided on the support portion 66e so as to correspond to the main body portion 62a and extend along the second direction Y.

[0023] The main body 62a is linear and extends longitudinally in the second direction Y, along the side walls 66a, 66b of the wall 66. In other words, the longitudinal direction of the main body 62a and the direction in which the side walls 66a, 66b of the wall 66 extend both coincide with the second direction Y.

[0024] Fig. 5 is a diagram schematically showing the positional relationship between a discharge electrode 62, a counter electrode 64, and a wall portion 66 in an electrostatic precipitator 60. In Fig. 5, three directions X, Y, and Z correspond to the three directions X, Y, and Z shown in Figs. 2 to 4, respectively.

[0025] As shown in Fig. 5, the wall portion 66 has a pair of side walls 66a, 66b and a pair of side walls 66c, 66d connecting the pair of side walls 66a, 66b. The pair of side walls 66a, 66b and the pair of side walls 66c, 66d stand substantially perpendicular to each other. The pair of side walls 66a, 66b are surface portions along a plane defined by the first direction X and the second direction Y, and form a pair in the longitudinal direction of the wall portion 66. In contrast, the pair of side walls 66c, 66d are surface portions along a plane defined by the first direction X and the third direction Z, and form a pair in the lateral direction of the wall portion 66.

[0026] The protrusions 62b are arranged in a line along the wall 66. Each of the protrusions 62b protrudes toward the wall 66. In the illustrated example, half of the protrusions 62b are arranged at approximately equal intervals on each of a pair of sides 63a, 63b along the longitudinal direction (second direction Y) of the main body 62a. Each of the protrusions 62b arranged on one side 63a protrudes from the side 63a toward the side wall 66a. In contrast, each of the protrusions 62b arranged on the other side 63b protrudes from the side 63b toward the side wall 66b.

[0027] Each of the protrusions 62b has a shape that protrudes at an acute angle when viewed from the opposing direction of the discharge electrode 62 and the counter electrode 64. In the illustrated example, each of the protrusions 62b protrudes in a substantially triangular shape when viewed from the first direction X, and an apex 62p of the triangle is disposed at a distance from the side walls 66a, 66b without coming into contact with the side walls 66a, 66b.

[0028] Fig. 6 is a plan view schematically showing the counter electrode 64 from the upstream side of the air flow passing through the electrostatic precipitator 60. In Fig. 6, three directions X, Y, and Z correspond to the three directions X, Y, and Z shown in Figs. 2 to 4, respectively.

[0029] As shown in FIG. 6 , the counter electrode 64 has a honeycomb structure in cross section in a plane perpendicular to the flow of air passing through the electrostatic precipitator 60, specifically, the air passing through the counter electrode 64. This plane perpendicular to the air flow corresponds to the plane defined by the second direction Y and the third direction Z. In the illustrated example, the counter electrode 64 has a main body 64a and a frame 64b. The main body 64a is an electrode portion having a honeycomb structure and is a portion that captures and collects dust contained in the air passing through the electrostatic precipitator 60. In order to capture the dust, the main body 64a has a predetermined length (thickness) in the flow direction of the air passing through the electrostatic precipitator 60 (first direction X). The frame 64b is a lattice-shaped frame that holds the main body 64a and is integrated with the wall 66.

[0030] In the main body portion 64a, it is desirable that the cell size (S) of the honeycomb structure is larger than 1 / 25 inch and smaller than 1 / 4 inch (1 / 25 < S < 1 / 4). As shown enlarged in FIG. 6, the cell size (S) is the distance (shortest distance) between two parallel sides 641 and 642 of the regular hexagon of the honeycomb structure, and is a value indicating the density of the honeycomb structure.

[0031] By forming the main body portion 64a into a honeycomb structure, the resistance of the air passing through the counter electrode 64 (ventilation resistance) can be suppressed. By setting the cell size (S) [inch] of the honeycomb structure of the main body portion 64a so as to satisfy the relational expression 1 / 25 < S < 1 / 4, it is possible to appropriately suppress an increase in the ventilation resistance of the counter electrode 64, and more specifically, of the ventilation path 601, and to secure a dust collection area and appropriately maintain the dust collection performance.

[0032] FIG. 7 is a diagram showing a comparison of the ventilation resistance of the counter electrode 64, the discharge area of the counter electrode 64, and the dust collection performance of the counter electrode 64 when the cell size (S) is 1 / 25 [inch], 1 / 8 [inch], and 1 / 4 [inch]. In FIG. 7, a comparison is shown as an example when the dust collection performance when the cell size (S) is 1 / 8 [inch] is taken as 100 [%]. The ventilation resistance of the counter electrode 64 is the resistance of the air passing through the counter electrode 64. The discharge area of the counter electrode 64 is the area where the counter electrode 64 receives the corona discharge generated from the discharge electrode 62, and corresponds to the dust collection area of the counter electrode 64.

[0033] As shown in Fig. 7, for the counter electrode 64 having a honeycomb structure, as the cell size (S) becomes smaller, such as 1 / 4 [inch], 1 / 8 [inch], and 1 / 25 [inch], the density of the honeycomb structure becomes larger. Therefore, as shown by the arrow in Fig. 7, the ventilation resistance in such a counter electrode 64 is smaller for 1 / 4 [inch] than for 1 / 8 [inch], and larger for 1 / 25 [inch]. Similarly, as shown by the arrow in Fig. 7, the discharge area in such a counter electrode 64 is smaller for 1 / 4 [inch] than for 1 / 8 [inch], and larger for 1 / 25 [inch].

[0034] Also, when the dust collection performance when the cell size (S) is 1 / 8 [inch] is taken as 100 [%], the dust collection performance when the cell size (S) is 1 / 4 [inch] is 96.8 [%], and the dust collection performance when the cell size (S) is 1 / 25 [inch] is 93.2 [%]. Therefore, the dust collection performance decreases in both cases where the cell size (S) is 1 / 4 [inch] and 1 / 25 [inch] compared to the case where the cell size (S) is 1 / 8 [inch].

[0035] Therefore, as shown in Fig. 7, by setting the cell size (S) [inch] of the honeycomb structure of the main body 64a so as to satisfy the relational expression 1 / 25 < S < 1 / 4, it is possible to secure the dust collection area while keeping the ventilation resistance in the counter electrode 64 within an appropriate range. Furthermore, the dust collection performance can also be appropriately maintained.

[0036] Here, the relative positional relationship among the discharge electrode 62, the counter electrode 64, and the wall portion 66 in the present embodiment will be further described.

[0037] Figures 8 and 9 schematically show the positional relationship between the protrusions 62b of the discharge electrode 62 and the side walls 66a and 66b of the wall portion 66. FIG. 8 is a diagram schematically showing such a positional relationship among the three elements from the upstream side of the air flow passing through the electrostatic precipitator 60. FIG. 9 is a diagram schematically showing such a positional relationship among the three elements from a direction orthogonal to the air flow passing through the electrostatic precipitator 60. In FIGS. 8 and 9, the three directions X, Y, and Z respectively correspond to the three directions X, Y, and Z shown in FIGS. 2 to 4.

[0038] As shown in FIGS. 8 and 9, let the facing distance between the discharge electrode 62 and the counter electrode 64 be D1, and let the facing distance between the plurality of protrusions 62b of the discharge electrode 62 and the side walls 66a and 66b of the wall portion 66 be D2. The facing distance D1 is the distance between the surface portion 62t of the discharge electrode 62 facing the counter electrode 64 and the surface portion 64s of the counter electrode 64 facing the discharge electrode 62. The facing distance D2 is the maximum value of the distances at which each of the plurality of protrusions 62b faces the corresponding side walls 66a and 66b of the wall portion 66. In this case, the facing distance D2 is larger than the facing distance D1 and smaller than 1.5 times the facing distance D1 (D1 < D2 < 1.5×D1). In this embodiment, as an example, the facing distances between each of the plurality of protrusions 62b and the side walls 66a and 66b facing the protrusion 62b are all the same or have a slight difference that can be regarded as the same. That is, the facing distance D2 can be regarded as the same among all the protrusions 62b and the side walls 66a and 66b.

[0039] Setting these opposing distances D1 and D2 to satisfy this relationship can improve the dust collection efficiency per unit area of ​​the counter electrode 64. As a result, even when the area of ​​the counter electrode 64 is reduced, it is easier to ensure appropriate dust collection efficiency, and the electrostatic precipitator 60 can be made more compact. The area of ​​the counter electrode 64 is the area of ​​the surface portion of the counter electrode 64 through which air passes, which is located on the upstream side (upwind side) of the air flow. In the example shown in FIG. 5, of the surfaces 64s and 64t of the counter electrode 64 that are parallel to the plane defined by the second direction Y and the third direction Z, this is the area of ​​the lower surface portion 64s. Note that in the illustrated example, the area of ​​the lower surface portion 64s and the area of ​​the upper surface portion 64t are approximately the same.

[0040] FIG. 10 shows the relationship between the facing distance (D2) between the multiple protrusions 62b of the discharge electrode 62 and the side walls 66a, 66b of the wall portion 66, and the dust collection performance of the counter electrode 64. In FIG. 10, the horizontal axis represents the facing distance D2 as the "distance between the discharge electrode and the side wall," and the vertical axis represents the dust collection performance of the electrostatic precipitator 60, or more simply, the counter electrode 64, as "performance." The bar graph shows the dust collection performance of the entire counter electrode 64, compared with the overall performance of the counter electrode 64 when the facing distance D2 is 21 mm, which is set to 100%. The line graph shows the dust collection performance per unit area of ​​the counter electrode 64, compared with the performance per unit area of ​​the counter electrode 64 when the facing distance D2 is 21 mm, which is set to 100%.

[0041] As shown by the bar graph in Fig. 10, the dust collection performance of the entire counter electrode 64 improves as the facing distance D2 increases from 15 mm to 16 mm, 21 mm, and 39 mm. On the other hand, as shown by the line graph in Fig. 10, when the facing distance D2 is 15 mm and 16 mm, the dust collection performance per unit area of ​​the counter electrode 64 is slightly higher than when the facing distance D2 is 21 mm (100%). In contrast, when the facing distance D2 is increased from 21 mm to 39 mm, the dust collection performance per unit area of ​​the counter electrode 64 decreases to about 60%.

[0042] Therefore, as shown in Figure 10, by setting the opposing distance (D2) between the multiple protrusions 62b of the discharge electrode 62 and the side walls 66a, 66b of the wall portion 66 to approximately 21 mm, it is possible to improve both the overall dust collection performance of the opposing electrode 64 and the dust collection performance per unit area of ​​the opposing electrode 64.

[0043] 8 and 9, the maximum distance between adjacently arranged projections 62b of the discharge electrode 62 is defined as P, and the number of projections 62b that the discharge electrode 62 has is defined as N. In the illustrated example, the distance P is the distance between the vertices 62p of adjacently arranged projections 62b of the multiple projections 62b. Note that, as an example, in the illustrated example, the distance P is approximately the same for all distances between the vertices 62p of adjacently arranged projections 62b. Also, FIG. 2 illustrates an example where the number (N) of projections 62b is 46.

[0044] In this case, the ratio (D1 / P) of the opposing distance D1 to the distance P is greater than the value obtained by multiplying the number N of protrusions 62b by 0.0121 and adding 0.5367, and is less than the value obtained by multiplying the number N of protrusions 62b by 0.0133 and adding 0.5932 ((0.0121×N+0.5367)<(D1 / P)<(0.0133×N+0.5932)).

[0045] Furthermore, the ratio (D1 / P) of the facing distance D1 to the distance P is greater than 0.86 ((D1 / P)>0.86).

[0046] By setting the number N of these protrusions 62b, the distance P, and the opposing distance D1 to satisfy this relational expression, when a constant voltage is applied to the discharge electrode 62 having N protrusions 62b, it is possible to appropriately set the opposing distance D1 between the discharge electrode 62 and the counter electrode 64. This makes it possible to improve the dust collection performance of the electrostatic precipitator 60.

[0047] Fig. 11 shows the relationship between the number (N) of protrusions 62b of the discharge electrode 62 and the ratio (D1 / P) of the facing distance D1 to the distance P between the protrusions 62b. In Fig. 11, the horizontal axis shows the number N of the protrusions 62b of the discharge electrode 62 as "number of discharge electrodes N", and the vertical axis shows the ratio D1 / P of the facing distance D1 to the distance P as "distance between electrodes / distance between protrusions D1 / P".

[0048] A solid line L in FIG. 11 indicates a standard value of the ratio D1 / P of the opposing distance D1 to the distance P, as a function of the number of electrodes (the number of protrusions 62b) N. A dashed line L1 in FIG. 11 indicates a lower threshold value of the ratio D1 / P as a function of the number of electrodes N ((D1 / P)=(0.0121×N+0.5367)). The lower threshold value here is set to -5% of the standard value of the ratio D1 / P indicated by the solid line L. A dashed line L2 in FIG. 11 indicates an upper threshold value of the ratio D1 / P as a function of the number of electrodes N ((D1 / P)=(0.0133×N+0.5932)). The upper threshold value here is set to +5% of the standard value of the ratio D1 / P indicated by the solid line L.

[0049] 11, in order to make the value of D1 / P greater than 0.86, it is preferable that the number of electrodes (the number of protrusions 62b) N is equal to or greater than 21. For example, when a plurality of protrusions 62b are arranged at approximately equal intervals, half on each of a pair of sides 63a, 63b along the longitudinal direction (second direction Y) of the main body 62a as shown in FIG. 5, it is sufficient to arrange 11 or more protrusions 62b on each of the pair of sides 63a, 63b.

[0050] As described above, the electrostatic precipitator 60 according to this embodiment can suppress the ventilation resistance in the ventilation passage 601 and improve the dust collection performance at the counter electrode 64. That is, it is possible to appropriately suppress the ventilation resistance of the electrostatic precipitator 60 and improve the dust collection performance. As a result, by providing such an electrostatic precipitator 60 in the indoor unit 1 of an air conditioner, for example, when the blower 10 draws indoor air through the suction port 87, the suction resistance can be suppressed, and dust can be appropriately collected from the drawn air, thereby purifying the air.

[0051] Although the embodiments of the present invention have been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention. Such novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the inventions and their equivalents as defined in the claims. [Explanation of symbols]

[0052] 1...indoor unit of air conditioner, 2...unit body, 3...panel (decorative panel), 4...casing, 10...blower, 60...electrostatic precipitator, 62...discharge electrode, 62a...main body, 62b...projection, 62p...vertex, 62t...surface, 63a, 63b...side of main body, 64...counter electrode, 64a...main body, 64b...frame, 64s, 64t...surface, 66...wall, 66a, 66b, 66c, 66d...side wall, 66e...support, 66f...base, 80...grill (intake grill), 81...frame, 82...outer frame, 83...lattice, 85a...first side, 85b...second side, 85c...third side, 85d...fourth side, 86 a, 86b, 86c, 86d...corner portion, 87...intake port, 88...outlet port, 89...louver, 601...ventilation channel, 641, 642...two sides that determine the honeycomb size, D1...opposing distance between the discharge electrode and the counter electrode, D2...opposing distance between the multiple protrusions of the discharge electrode and the side wall of the wall portion, N...number of protrusions on the discharge electrode, P...maximum distance between adjacently arranged protrusions of the discharge electrode (distance between the vertices of adjacently arranged protrusions among the multiple protrusions), S...distance between two parallel sides of the regular hexagon of the honeycomb structure (shortest distance), X...first direction, Y...second direction, Z...third direction.

Claims

1. a discharge electrode disposed upstream of the air flow to generate a corona discharge; a counter electrode disposed downstream of the air flow opposite the discharge electrode to collect dust contained in the air; a wall portion between the discharge electrode and the counter electrode that guides the air from the discharge electrode toward the counter electrode, the discharge electrode has a plurality of protrusions arranged along the wall portion and protruding toward the wall portion, When the opposing distance between the discharge electrode and the counter electrode is D1 and the opposing distance between the plurality of protrusions of the discharge electrode and the wall portion is D2, D1<D2<1.5×D1 Fulfilling the relationship Electrostatic precipitator.

2. The number of the protrusions of the discharge electrode is set to N, When the maximum distance between adjacent protrusions among the plurality of protrusions is P, (0.0121 × N + 0.5367) < (D1 / P) < (0.0133 × N + 0.5932), and (D1 / P)>0.86 satisfy the following relation:

2. The electrostatic precipitator according to claim 1.

3. the counter electrode has a honeycomb structure in cross section in a plane perpendicular to the air flow, When the distance between two parallel sides of the regular hexagon of the honeycomb structure is S, 1 / 25<S<1 / 4 The following relation is satisfied:

3. The electric dust collector according to claim 1 or 2.

4. a heat exchanger that exchanges heat between the air and the refrigerant; a blower that draws in the air from inside the room and blows the air that has been heat exchanged in the heat exchanger into the room; a box-shaped housing that opens toward the room and houses the heat exchanger and the fan; a panel that covers the opening of the housing from the inside of the room, the panel having an inlet that draws in air from the room and an outlet that blows out air that has been heat exchanged in the heat exchanger; The electric dust collector according to claim 3 is disposed at the inlet or the outlet. Air conditioner indoor unit.

Images