Electric dust collector and indoor unit of air conditioner

Abstract

The present invention addresses the problem of providing an electric dust collector capable of suppressing ventilation resistance and improving dust collection performance, and an indoor unit of an air conditioner provided with the electric dust collector. The electric dust collector includes a discharge electrode, a counter electrode, and a wall portion. The discharge electrode is disposed on the upstream side of the flow of air and generates corona discharge. The counter electrode is disposed on the downstream side of the flow of the air so as to face the discharge electrode, and collects dust contained in the air. The wall portion guides the air between the discharge electrode and the counter electrode from the discharge electrode toward 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 facing electrode is D1 and the facing distance between the plurality of protrusions of the discharge electrode and the wall part is D2, the relationship D1 < D2 < 1.5 * D1 is satisfied.

Description

Technical Field

[0001] Embodiments of the present invention relate to an electrostatic precipitator and an indoor unit of an air conditioner equipped with the electrostatic precipitator. Background Technology

[0002] There are cases where an electrostatic precipitator is installed in the indoor unit of an air conditioner (hereinafter referred to as the indoor unit). An electrostatic precipitator is a device that charges dust particles in the air passing through a ventilation path and uses electrostatic force to capture and collect the dust. For example, when the indoor unit draws in indoor air, the electrostatic precipitator installed in the indoor unit collects the dust contained in the drawn-in air, thereby purifying the air. The electrostatic precipitator is located at the air intake of the indoor unit, where it draws in indoor air. Thus, the air drawn in from the intake passes through the electrostatic precipitator.

[0003] Therefore, in electrostatic precipitators installed in indoor units, it is required to suppress ventilation resistance in the ventilation path and improve dust collection performance.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 11-249382

[0007] Patent Document 2: Japanese Patent Application Publication No. 2019-171334 Summary of the Invention

[0008] The problem that the invention aims to solve

[0009] The present invention was made in view of this, and its object is to provide an electrostatic precipitator capable of suppressing ventilation resistance and improving dust collection performance, and an indoor unit of an air conditioner equipped with the electrostatic precipitator.

[0010] Methods for solving problems

[0011] According to one embodiment, the electrostatic precipitator includes a discharge electrode, a counter electrode, and a wall. The discharge electrode is positioned upstream of the airflow to generate corona discharge. The counter electrode is positioned downstream of the airflow and opposite the discharge electrode to collect dust contained in the 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 arranged along the wall and protruding toward the wall. When the distance between the discharge electrode and the counter electrode is set to D1, and the distance between the plurality of protrusions of the discharge electrode and the wall is set to D2, the relationship D1 < D2 < 1.5 × D1 is satisfied. Attached Figure Description

[0012] Figure 1 This is a perspective view of the indoor unit of the ceiling-embedded air conditioner according to this embodiment.

[0013] Figure 2 This is a top view that schematically represents the electrostatic precipitator of this embodiment from the indoor side (the upstream side of the airflow through the electrostatic precipitator).

[0014] Figure 3 Is Figure 2 The portion indicated by arrow A2 is a cross-sectional view of the electrostatic precipitator of this embodiment, roughly showing the direction of the arrow.

[0015] Figure 4 It includes Figure 3 The cross-section shown is a perspective view of the electrostatic precipitator of this embodiment.

[0016] Figure 5 This diagram schematically illustrates the positional relationship between the discharge electrode, the counter electrode, and the wall portion in the electrostatic precipitator of this embodiment.

[0017] Figure 6 This is a top view of the counter electrode of the electrostatic precipitator of this embodiment, schematically shown from the downstream side of the air flow through the counter electrode.

[0018] Figure 7 The graph is a comparative representation of the ventilation resistance, discharge area, and dust collection performance of the opposing electrode of the electrostatic precipitator of this embodiment based on the compartment dimensions of the honeycomb structure.

[0019] Figure 8 This diagram schematically shows the relative positional relationship of the discharge electrode, the counter electrode, and the wall of the electrostatic precipitator in this embodiment from the upstream side of the airflow through the electrostatic precipitator.

[0020] Figure 9 This diagram schematically shows the relative positions of the discharge electrode, the counter electrode, and the wall of the electrostatic precipitator in this embodiment, from a direction orthogonal to the airflow passing through the precipitator.

[0021] Figure 10 This is a diagram showing the relationship between the opposing distance (D2) between the multiple protrusions of the discharge electrode and the side wall of the wall portion of the electrostatic precipitator in this embodiment and the dust collection performance of the opposing electrode.

[0022] Figure 11 This is a graph showing the relationship between the number (N) of the discharge electrode protrusions of the electrostatic precipitator in this embodiment and the ratio (D1 / P) of the opposing distance (D1) to the distance (P) of the protrusions. Detailed Implementation

[0023] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0024] Figure 1 This is a perspective view of the indoor unit of the ceiling-recessed air conditioner according to this embodiment. Figure 1 As shown, the indoor unit 1 of the air conditioner has a main body 2 mounted on the back of the ceiling and a panel (hereinafter referred to as decorative panel) 3 mounted on the lower end of the main body 2 as its main elements. The main body 2 has a housing 4. The housing 4 is configured as a box shape with an opening facing the room, and is suspended from a beam on the back of the ceiling, for example, by a plurality of suspension bolts (not shown).

[0025] A blower 10 is housed inside the housing 4. The blower 10 draws in air from the air-conditioned space, i.e., the room, and blows the air out of the room after heat exchange in a heat exchanger (not shown). In the example shown, a centrifugal fan that draws in air axially and blows it out circumferentially serves as the blower 10. The heat exchanger exchanges heat between the air in the air-conditioned space, i.e., the room, and the refrigerant, thus conditioning the air in the room. The heat exchanger stands upright inside the housing 4, surrounding the blowing side of the blower 10.

[0026] The decorative panel 3 is positioned along the ceiling (not shown) of the air-conditioned space, covering the opening at the lower end of the housing 4 from the indoor side. The decorative panel 3 includes a grille (hereinafter referred to as the intake grille) 80 and a frame 81.

[0027] The intake grille 80 is located in the center of the decorative panel 3 and is rotatably supported on the frame 81. It is an element that shields the intake port 87 that draws indoor air into the housing 4. The intake grille 80 has a generally square outer frame portion 82 and a grid portion 83 surrounded by the outer frame portion 82. The grid portion 83 is located directly below the blower 10.

[0028] The frame 81 of the decorative panel 3 is a generally square element surrounding the intake grille 80, having first to fourth sides 85a, 85b, 85c, 85d and four corners 86a, 86b, 86c, 86d. The quadrilateral area surrounded by the inner periphery of the first to fourth sides 85a, 85b, 85c, 85d defines the intake port 87. The decorative panel 3 is detachably connected to the housing 4 at the four corners 86a, 86b, 86c, 86d of the frame 81. Thus, the lower end of the unit body 2 is covered by the decorative panel 3.

[0029] The decorative panel 3 has four air outlets 88 that blow air after heat exchange by the heat exchanger into the room. The air outlets 88 are formed on the first to fourth sides 85a, 85b, 85c, and 85d of the frame 81.

[0030] Four louvers 89 are rotatably supported on the frame 81 of the decorative panel 3. The louvers 89 are elements that change the direction of airflow from the outlet 88 into the room, and are formed into flat, elongated plates. The louvers 89 can rotate between a closed position (closing the outlet 88) and an open position (tilted to open the outlet 88). When the louvers 89 are rotated to the closed position, the four louvers 89 are horizontal, completely covering the first to fourth sides 85a, 85b, 85c, and 85d of the frame 81.

[0031] In the example shown, one side of the outer frame 82 of the intake grille 80 of the decorative panel 3 is rotatably connected to the third side 85c of the frame 81. Therefore, the intake grille 80 can rotate between a first position with the intake port 87 closed and a second position with the intake port 87 open.

[0032] The main body 2 includes an electrostatic precipitator 60. In this embodiment, as an example, the electrostatic precipitator 60 is mounted on the housing 4 with the suction port 87 disposed thereon. In the example shown, two electrostatic precipitators 60 are mounted on the housing 4, but the number is not limited thereto. The electrostatic precipitators 60 configured in this way are located upstream of the airflow from the blower 10 housed in the housing 4, where the blower 10 draws air from the interior of the housing 4.

[0033] Therefore, the air drawn into the interior of the housing 4 by the blower 10 passes through the suction port 87 and then through the electrostatic precipitator 60. Thus, the electrostatic precipitator 60 collects dust particles contained in the air drawn in by the blower 10 from the interior into the housing 4, thereby purifying the air. Furthermore, in the example shown, the electrostatic precipitator 60 is positioned at the suction port 87, but it could also be positioned at the discharge port 88.

[0034] Figures 2 to 4 The configuration of the electrostatic precipitator 60 of this embodiment is shown in a general way. Figure 2 This is a top view of the electrostatic precipitator 60, roughly shown from the indoor side, or in other words, from the upstream side of the airflow through the electrostatic precipitator 60. Figure 3 Is Figure 2 The section indicated by arrow A2 roughly represents a cross-sectional view of the electrostatic precipitator 60 in the direction of the arrow. Figure 4 It is a general representation of inclusion. Figure 3 The cross-section shown is a perspective view of the electrostatic precipitator 60.

[0035] like Figures 2 to 4As shown, the electrostatic precipitator 60 has two electrode sections, a discharge electrode 62 and a counter electrode 64, arranged approximately in parallel opposite directions. The discharge electrode 62 is disposed upstream of the airflow passing through the electrostatic precipitator 60 and is used to generate corona discharge. The upstream side of the airflow passing through the electrostatic precipitator 60 is the upwind side of the airflow, i.e., the side where the airflow is blowing. Figure 2 The front side of the electrostatic precipitator 60. The opposing electrode 64 is positioned downstream of the airflow through the electrostatic precipitator 60 and is an electrode (collecting electrode) for collecting dust contained in that air. The downstream side of the airflow through the electrostatic precipitator 60 is the downwind side of the airflow, i.e., the side where the airflow is ventral. Figure 2 The back side of the middle.

[0036] The electrostatic precipitator 60 includes a wall portion 66 that forms a ventilation passage 601 through which air flows. The wall portion 66, located between the discharge electrode 62 and the counter electrode 64, guides the air flowing in the ventilation passage 601 from the discharge electrode 62 toward the counter electrode 64. Specifically, in the ventilation passage 601 formed by the wall portion 66, the discharge electrode 62 is positioned at the upstream end of the airflow in the ventilation passage 601, and the counter electrode 64 is positioned at the downstream end. Thus, at the ends of the ventilation passage 601, the air flowing in the ventilation passage 601 passes through both the discharge electrode 62 and the counter electrode 64. In other words, the ventilation passage 601 is a generally cylindrical shape with openings at both ends where the discharge electrode 62 and the counter electrode 64 are located.

[0037] The discharge electrode 62 is, for example, a plate-shaped or foil-shaped electrode, configured to have a main body 62a and a protrusion 62b. The main body 62a extends linearly in a plane perpendicular to the flow direction of air passing through the discharge electrode 62. The protrusion 62b protrudes from the main body 62a in a direction orthogonal to the direction extending from the main body 62a in this plane. Figures 2 to 4 In the diagram, the first direction X is along the direction of airflow through the electrostatic precipitator 60 (discharge electrode 62 and counter electrode 64), the second direction Y is along the direction extending from the main body 62a, and the third direction Z is along the direction protruding from the main body 62a by the protrusion 62b. These three directions X, Y, and Z are orthogonal to each other.

[0038] like Figures 2 to 4As shown, the main body 62a of the discharge electrode 62 is supported on a support portion 66e of the wall portion 66 (described later), and is positioned at the upstream end of the airflow in the ventilation passage 601 formed by the wall portion 66. In the example shown, the support portion 66e is configured as a lattice and extends along a plane defined by the second direction Y and the third direction Z. The main body 62a extends along the second direction Y while being placed on a pedestal 66f of the support portion 66e. The pedestal 66f extends from the support portion 66e in the first direction X by a predetermined length and is disposed on the support portion 66e in a manner corresponding to the main body 62a along the second direction Y.

[0039] The main body 62a is a relatively long straight line in the second direction Y, such that the long side extends along the side walls 66a and 66b of the wall portion 66. In other words, the long side of the main body 62a and the direction in which the side walls 66a and 66b of the wall portion 66 extend are both consistent with the second direction Y.

[0040] Figure 5 This diagram schematically illustrates the positional relationship between the discharge electrode 62, the opposing electrode 64, and the wall 66 in the electrostatic precipitator 60. Figure 5 In the middle, the three directions X, Y, and Z are respectively with Figures 2 to 4 The three directions shown are X, Y, and Z.

[0041] like Figure 5 As shown, the wall portion 66 has a pair of sidewalls 66a and 66b and a pair of sidewalls 66c and 66d connecting these sidewalls 66a and 66b. The pair of sidewalls 66a and 66b and the pair of sidewalls 66c and 66d stand approximately perpendicular to each other. The pair of sidewalls 66a and 66b are faces along a plane defined by a first direction X and a second direction Y, and are paired along the long side of the wall portion 66. In contrast, the pair of sidewalls 66c and 66d are faces along a plane defined by a first direction X and a third direction Z, and are paired along the short side of the wall portion 66.

[0042] Multiple protrusions 62b are arranged along the wall portion 66. These multiple protrusions 62b each protrude toward the wall portion 66. In the example shown, the multiple protrusions 62b are arranged at approximately equal intervals on each of a pair of sides 63a, 63b along the long side direction (second direction Y) of the main body portion 62a. The protrusions 62b arranged on one side 63a protrude toward the side wall 66a from that side 63a. Conversely, the protrusions 62b arranged on the other side 63b protrude toward the side wall 66b from that side 63b.

[0043] Viewed from the opposing direction of the discharge electrode 62 and the counter electrode 64, each protrusion 62b is shaped to protrude at an acute angle. In the example shown, each protrusion 62b protrudes in a generally triangular shape when viewed from the first direction X, and the vertices 62p of the triangle are arranged at intervals from the sidewalls 66a and 66b in a manner that does not connect with them.

[0044] Figure 6 This is a top view, schematically showing the opposing electrode 64, from the upstream side of the airflow through the electrostatic precipitator 60. Figure 6 In the middle, the three directions X, Y, and Z are respectively with Figures 2 to 4 The three directions shown are X, Y, and Z.

[0045] like Figure 6 As shown, the counter electrode 64 has a honeycomb structure in cross-section on a plane perpendicular to the airflow through the electrostatic precipitator 60, or more specifically, the airflow through the counter electrode 64. This plane perpendicular to the airflow corresponds to a plane defined by the second direction Y and the third direction Z. In the example shown, the counter electrode 64 has a main body portion 64a and a frame portion 64b. The main body portion 64a is the honeycomb-structured electrode portion, which captures and collects dust from the airflow through the electrostatic precipitator 60. To capture dust, the main body portion 64a has a predetermined length (thickness) in the airflow direction (first direction X) through the electrostatic precipitator 60. The frame portion 64b is a lattice-shaped frame that holds the main body portion 64a together with the wall portion 66.

[0046] In the main body 64a, the cell size (S) of the honeycomb structure is preferably greater than 1 / 25 inch and less than 1 / 4 inch (1 / 25 < S < 1 / 4). Figure 6 As shown in the magnified view, the compartment size (S) is the distance (shortest distance) between the two parallel sides 641 and 642 of the regular hexagon of the honeycomb structure, and is a value representing the density of the honeycomb structure.

[0047] By making the main body 64a into a honeycomb structure, the air resistance (ventilation resistance) passing through the counter electrode 64 can be suppressed. By setting the cell size (S) [inch] of the honeycomb structure of the main body 64a to satisfy the relationship 1 / 25 < S < 1 / 4, the increase in ventilation resistance of the counter electrode 64, or more specifically, the ventilation path 601, can be appropriately suppressed, and the dust collection area can be ensured while maintaining the dust collection performance appropriately.

[0048] Figure 7 This is a graph comparing the ventilation resistance, discharge area, and dust collection performance of the counter electrode 64 when the compartment size (S) is 1 / 25 inch, 1 / 8 inch, and 1 / 4 inch. Figure 7 The comparison shown is an example of the dust collection performance set to 100% when the compartment size (S) is 1 / 8 inch. The ventilation resistance of the counter electrode 64 is the air resistance through the counter electrode 64. The discharge area of ​​the counter electrode 64 is the area of ​​the counter electrode 64 that receives the corona discharge generated from the discharge electrode 62, and is equivalent to the dust collection area of ​​the counter electrode 64.

[0049] like Figure 7 As shown, the smaller the cell size (S) of the honeycomb-structured opposing electrode 64 (1 / 4 inch, 1 / 8 inch, 1 / 25 inch), the higher the density of the honeycomb structure. Therefore, compared to the case where the cell size (S) is 1 / 8 inch, as... Figure 7 As indicated by the middle arrow, the ventilation resistance of the opposing electrode 64 is lower at 1 / 4 inch and higher at 1 / 25 inch. Similarly, compared to the case where the compartment size (S) is 1 / 8 inch, as... Figure 7 As indicated by the middle arrow, the discharge area of ​​the counter electrode 64 is smaller at 1 / 4 inch and larger at 1 / 25 inch.

[0050] Furthermore, when the dust collection performance is set to 100% for a compartment size (S) of 1 / 8 inch, the dust collection performance is 96.8% for a compartment size (S) of 1 / 4 inch and 93.2% for a compartment size (S) of 1 / 25 inch. Therefore, the dust collection performance is lower for both the 1 / 4 inch and 1 / 25 inch compartment sizes compared to the 1 / 8 inch compartment size.

[0051] Therefore, as Figure 7 As shown, by setting the cell size (S) [inch] of the honeycomb structure of the main body 64a to satisfy the relationship 1 / 25 < S < 1 / 4, the ventilation resistance of the counter electrode 64 can be limited to an appropriate range, and the dust collection area can be ensured.

[0052] In turn, it can also maintain dust collection performance appropriately.

[0053] Here, the relative positional relationship between the discharge electrode 62, the counter electrode 64, and the wall portion 66 in this embodiment will be further explained.

[0054] Figure 8 as well as Figure 9 The schematic diagram shows the positional relationship between the protrusion 62b of the discharge electrode 62 and the sidewalls 66a and 66b of the wall portion 66. Figure 8This is a diagram schematically showing the positional relationship of the three elements from the upstream side of the airflow through the electrostatic precipitator 60. Figure 9 This diagram schematically illustrates the positional relationship of the three elements from a direction orthogonal to the airflow passing through the electrostatic precipitator 60. Figure 8 as well as Figure 9 In the middle, the three directions X, Y, and Z are respectively with Figures 2 to 4 The three directions shown are X, Y, and Z.

[0055] like Figure 8 as well as Figure 9 As shown, the opposition distance between the discharge electrode 62 and the opposing electrode 64 is defined as D1, and the opposition distance between the plurality of protrusions 62b of the discharge electrode 62 and the sidewalls 66a, 66b of the wall portion 66 is defined as D2. Opposition distance D1 is the distance between the face 62t of the discharge electrode 62 opposing the opposing electrode 64 and the face 64s of the opposing electrode 64 opposing the discharge electrode 62. Opposition distance D2 is the maximum value of the distances between each of the plurality of protrusions 62b and the corresponding sidewalls 66a, 66b of the wall portion 66. In this case, opposition distance D2 is greater than opposition distance D1 but less than 1.5 times opposition distance D1 (D1 < D2 < 1.5 × D1). Furthermore, in this embodiment, as an example, the opposition distances between each of the plurality of protrusions 62b and the sidewalls 66a, 66b opposite to the protrusion 62b are all the same or have only slight differences that can be considered to be the same. That is, the opposing distance D2 is considered to be the same between all protrusions 62b and sidewalls 66a, 66b.

[0056] By setting these opposing distances D1 and D2 to satisfy the following relationship, the dust collection efficiency per unit area of ​​the opposing electrode 64 can be improved. Therefore, even when the area of ​​the opposing electrode 64 is reduced, appropriate dust collection efficiency can be easily ensured, enabling miniaturization of the electrostatic precipitator 60. The area of ​​the opposing electrode 64 is the area of ​​the face of the opposing electrode 64 located on the upstream side (windward side) of the airflow. Figure 5 In the example shown, the area of ​​the lower face 64s is shown among the faces 64s and 64t of the opposing electrode 64, which are parallel to the plane defined by the second direction Y and the third direction Z. Furthermore, in the example shown, as an example, the area of ​​this lower face 64s is approximately the same as the area of ​​the upper face 64t.

[0057] Figure 10 This indicates the relationship between the opposing distance (D2) between the plurality of protrusions 62b of the discharge electrode 62 and the sidewalls 66a, 66b of the wall portion 66, and the dust collection performance of the opposing electrode 64. Figure 10In the graph, the horizontal axis represents the distance between the discharge electrode and the sidewall as "distance between the discharge electrode and the sidewall," and the vertical axis represents the dust collection performance of the electrostatic precipitator 60, or more simply, the discharge electrode 64 as "performance." The bar chart represents the overall dust collection performance of the discharge electrode 64 by comparing the overall performance of the discharge electrode 64 with a distance between the discharge electrode and the sidewall of 21 mm, where the distance between the discharge electrode and the sidewall is ...

[0058] like Figure 10 As shown in the bar chart, the greater the opposing distance D2 becomes to 15 mm, 16 mm, 21 mm, and 39 mm, the better the overall dust collection performance of the opposing electrode 64. On the other hand, as... Figure 10 As shown in the line graph, when the opposing distance D2 is 15 mm and 16 mm, the dust collection performance per unit area of ​​the opposing electrode 64 is slightly higher than that when the opposing distance D2 is 21 mm (100%). Conversely, if the opposing distance D2 is increased from 21 mm to 39 mm, the dust collection performance per unit area of ​​the opposing electrode 64 decreases to about 60%.

[0059] Therefore, according to Figure 10 By setting the opposing distance (D2) between the multiple protrusions 62b of the discharge electrode 62 and the sidewalls 66a and 66b of the wall portion 66 to about 21 mm, the overall dust collection performance of the opposing electrode 64 and the dust collection performance per unit area of ​​the opposing electrode 64 can be improved.

[0060] In addition, such as Figure 8 as well as Figure 9 As shown, the maximum distance between adjacent protrusions 62b of the discharge electrode 62 is defined as P, and the number of protrusions 62b of the discharge electrode 62 is defined as N. In the example shown, distance P is the distance between the vertices 62p of adjacent protrusions 62b. Furthermore, in the example shown, distance P is approximately the same as any distance between the vertices 62p of adjacent protrusions 62b. Additionally, in... Figure 2 The example shown is when the number (N) of protrusions 62b is 46.

[0061] In this case, the ratio of the opposing distance D1 to the distance P (D1 / P) is greater than the value obtained by setting the number of protrusions 62b N to 0.0121 times and adding 0.5367, and less than the value obtained by setting the number of protrusions 62b N to 0.0133 times and adding 0.5932 ((0.0121×N+0.5367)<(D1 / P)<(0.0133×N+0.5932).

[0062] In addition, the ratio of the opposing distance D1 to the distance P (D1 / P) is greater than 0.86 ((D1 / P)>0.86).

[0063] By setting the number N of these protrusions 62b, their distance P, and their opposing distance D1 to satisfy the following relationship, when a constant voltage is applied to the discharge electrode 62 with N protrusions 62b, the opposing distance D1 between the discharge electrode 62 and the opposing electrode 64 can be appropriately set. This improves the dust collection performance of the electrostatic precipitator 60.

[0064] Figure 11 This indicates the relationship between the number (N) of the protrusions 62b of the discharge electrode 62 and the ratio (D1 / P) of the opposing distance D1 of the protrusions 62b to the distance P. Figure 11 In the diagram, the horizontal axis represents the number N of the protrusions 62b of the discharge electrode 62 as "number of discharge electrodes N", and the vertical axis represents the ratio D1 / P of the opposing distance D1 to the distance P as "distance between electrodes / distance between protrusions D1 / P".

[0065] Figure 11 The solid line L shown represents the standard value of the ratio D1 / P, which is the ratio of the opposing distance D1 to the distance P, based on the number of electrodes (the number of protrusions 62b). Figure 11 The dashed line L1 shown represents the lower threshold of the ratio D1 / P based on the number of electrodes N ((D1 / P) = (0.0121 × N + 0.5367)). This lower threshold is 5% of the standard value of the ratio D1 / P shown by the solid line L. Figure 11 The dashed line L2 shown represents the upper threshold of the ratio D1 / P based on the number of electrodes N ((D1 / P) = (0.0133 × N + 0.5932)). This upper threshold is 5% of the standard value of the ratio D1 / P shown by the solid line L.

[0066] like Figure 11 As shown by the solid line L, in order to make the value of D1 / P greater than 0.86, the number of electrodes (the number of protrusions 62b) N is preferably 21 or more. For example, as Figure 5As shown, if a plurality of protrusions 62b are arranged at approximately equal intervals on each of a pair of sides 63a and 63b along the long side direction (second direction Y) of the main body 62a, then 11 or more protrusions 62b can be arranged on each pair of sides 63a and 63b.

[0067] Thus, the electrostatic precipitator 60 according to this embodiment can suppress ventilation resistance in the ventilation path 601 and improve dust collection performance in the counter electrode 64. That is, it is possible to appropriately achieve both suppression of ventilation resistance and improvement of dust collection performance of the electrostatic precipitator 60. As a result, by including this electrostatic precipitator 60 in the indoor unit 1 of the air conditioner, for example, when the blower 10 draws indoor air from the intake port 87, its suction resistance is suppressed.

[0068] Furthermore, it can properly collect dust from the inhaled air, thus purifying the air.

[0069] The embodiments of the present invention have been described above, but these embodiments are provided as examples and are not intended to limit the scope of the invention. This new embodiment can be implemented in various other ways, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included within the scope and spirit of the invention, and are encompassed by the invention as described in the claims and its equivalents.

[0070] Explanation of reference numerals in the attached figures

[0071] 1…Indoor unit of air conditioner; 2…Unit body; 3…Panel (decorative panel); 4…Housing; 10…Blower; 60…Electrostatic precipitator; 62…Discharge electrode; 62a…Main body; 62b…Protrusion; 62p…Vertex; 62t…Face; 63a, 63b…Side of main body; 64…Counter electrode; 64a…Main body; 64b…Frame; 64s, 64t…Face; 66…Wall; 66a, 66b, 66c, 66d…Side wall; 66e…Support; 66f…Base; 80…Grate (suction grille); 81…Frame; 82…Outer frame; 83…Grid; 85a…First side; 85b…Second side; 85c…Third side; 85d… Quadrilaterals; 86a, 86b, 86c, 86d… Corners; 87… Inlet; 88… Outlet; 89… Louvers; 601… Ventilation path; 641, 642… Two sides of the specified honeycomb size; D1… Opposite distance between the discharge electrode and the opposing electrode; D2… Opposite distance between the multiple protrusions of the discharge electrode and the sidewalls of the wall; N… Number of protrusions of the discharge electrode; P… Maximum distance between adjacent protrusions of the discharge electrode (distance between the vertices of adjacent 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. An electrostatic precipitator, comprising: The discharge electrode is positioned upstream of the airflow to generate corona discharge. A counter electrode, disposed opposite the discharge electrode on the downstream side of the airflow, collects dust contained in the air; and The wall portion, between the discharge electrode and the counter electrode, guides the air from the discharge electrode toward the counter electrode. The discharge electrode has a plurality of protrusions arranged along the wall and protruding toward the wall. When the opposing distance between the discharge electrode and the opposing electrode is set to D1, and the opposing distance between the plurality of protrusions of the discharge electrode and the wall portion is set to D2, the following conditions are met: The relationship is D1 < D2 < 1.5 × D1.

2. The electrostatic precipitator according to claim 1, When the number of protrusions in the discharge electrode is set to N, When the maximum distance between adjacent protrusions in a plurality of protrusions is set as P, the following condition is satisfied: The relationship is (0.0121×N+0.5367)<(D1 / P)<(0.0133×N+0.5932)and(D1 / P)>0.

86.

3. The electrostatic precipitator according to claim 1 or 2, The opposing electrode has a honeycomb structure in cross-section on a plane perpendicular to the airflow. When the distance between two parallel sides of the regular hexagon in the honeycomb structure is set as S, the following conditions are met: The relationship is 1 / 25 < S < 1 / 4.

4. An indoor unit of an air conditioner, comprising: A heat exchanger that facilitates heat exchange between the air and the refrigerant; A blower draws in air from the room and blows the air, after heat exchange by the heat exchanger, back into the room. The housing is configured as a box shape with an opening facing the interior, and houses the heat exchanger and the blower; The panel has an intake port for drawing in air from the interior and an outlet port for blowing out air that has been heat-exchanged by the heat exchanger, and covers the opening of the housing from the interior side; as well as The electrostatic precipitator according to claim 3 is disposed at the inlet or the outlet.

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