Silencing device and electric appliance applying same

Abstract

The invention discloses a silencing device and an electric appliance applying the silencing device, the silencing device comprises a hollow shell, the cross section of the shell is rectangular, and the cross section is any cross section perpendicular to the thickness direction of the shell; a first air duct inner surface and a second air duct inner surface are arranged in the space in the shell, the first air duct inner surface is a sound absorption wall surface, the space between the first air duct inner surface and the second air duct inner surface forms an air duct, and the first air duct inner surface and the second air duct inner surface form all wall surfaces of the air duct; one edge of the shell is provided with a first port which serves as an air outlet and can allow noise sound waves to be transmitted in, and any straight line intersecting with the first port is made; when the inner surface of the second air duct is a rigid body wall surface, the straight line intersects with the inner surface of the first air duct at least once; or after being reflected on the inner surface of the second air duct, the light intersects with the inner surface of the first air duct at least once; when the second air duct inner surface is a sound absorption wall surface, the straight line intersects with the first air duct inner surface or the second air duct inner surface at least once.

Description

TECHNICAL FIELD

[0001] The present application relates to noise reduction technology, in particular to a silencing device and an electric appliance using the same. BACKGROUND

[0002] With the continuous improvement of living standards, consumers' demand for household appliances has shifted from single functional demand to diversified quality demand. For example, air conditioners not only require cooling and heating functions, but also pursue energy saving, environmental protection and quietness; range hoods need to achieve low noise operation while ensuring efficient smoke exhaust; gas water heaters need to have both stable hot water supply and quiet performance. Therefore, quiet performance has become one of the core indicators for consumers to evaluate the quality of household appliances, directly affecting the market competitiveness and user experience of products.

[0003] Among the noise sources of household appliances, the noise generated by the fan is one of the most common and prevalent noise sources. However, as the core functional module of household appliances, the performance of the fan is directly related to key indicators such as the cooling and heating efficiency, operation reliability, and smoke exhaust effect of the product, so it is not possible to simply reduce the fan power to achieve noise reduction. In addition, since the fan noise is mainly transmitted outward through the air duct, it is also not possible to reduce the fan noise by isolating or closing the air duct.

[0004] The existing noise reduction technology of household appliances, such as the gas water heater and its air duct structure disclosed in Chinese Patent No. 202110411913.2, the air duct structure of the gas water heater includes: an auxiliary plate for fixed connection with the shell of the gas water heater, and a back plate fixedly connected with the auxiliary plate and forming an air duct; wherein the auxiliary plate and the back plate are located on the same side of the shell; the air inlet of the air duct is arranged at the top of the back plate, and the air outlet of the air duct is arranged at the bottom of the auxiliary plate and is used for communication with the air inlet of the fan, or the air inlet of the air duct is arranged at the bottom of the back plate, and the air outlet of the air duct is arranged at the top of the auxiliary plate; the air duct is provided with a silencing structure. However, this silencing structure extends along the fluid flow direction and can have a certain noise reduction effect on fluid noise, but the fan noise in the water heater shell can be directly transmitted from the channel between the silencing structures, and the noise reduction effect cannot meet the expectations. Therefore, further improvement is needed. SUMMARY

[0005] The first technical problem to be solved by the present application is to provide a silencing device that can improve the noise reduction effect.

[0006] The second technical problem to be solved by the present application is to provide an electric appliance using the above-mentioned silencing device.

[0007] The application solves the first technical problem by adopting the following technical scheme: a muffling device, comprising a hollow shell, the cross section of the shell is rectangular, the cross section is any cross section perpendicular to the thickness direction of the shell, characterized in that:

[0008] The space in the shell is provided with a first air duct inner surface and a second air duct inner surface, the first air duct inner surface is a sound absorbing wall surface, the space between the first air duct inner surface and the second air duct inner surface constitutes an air duct, the first air duct inner surface and the second air duct inner surface constitute all the wall surfaces of the air duct, and the second air duct inner surface is a rigid wall surface or a sound absorbing wall surface;

[0009] In any cross section perpendicular to the thickness direction of the shell, one side of the shell is provided with a first port as an air outlet and capable of allowing noise sound waves to enter, and any straight line intersecting the first port:

[0010] When the second air duct inner surface is a rigid wall surface, the straight line intersects the first air duct inner surface at least once, or intersects the first air duct inner surface at least once after being reflected on the second air duct inner surface;

[0011] When the second air duct inner surface is a sound absorbing wall surface, the straight line intersects the first air duct inner surface or the second air duct inner surface at least once.

[0012] Therefore, the sound waves emitted from the first port in any direction will be reflected on the sound absorbing wall surface at least once before being emitted from the air inlet, and will not be directly emitted from the air inlet, and the rigid wall surface can increase the number of sound wave reflections, so that the sound waves collide with the first air duct inner surface more times, further reducing noise.

[0013] Further, the second air duct inner surface has two, which are oppositely arranged along the X-axis direction;

[0014] In any cross section perpendicular to the thickness direction of the shell, the first air duct inner surface comprises a first straight line segment, a first curved segment and a second curved segment, the first straight line segment extends from the first port to the inside of the shell along the Y-axis direction, the end points of the first curved segment and the second curved segment are respectively connected to the bottom end point of the first straight line segment away from the first port, and the first straight line segment is located between the two second air duct inner surfaces;

[0015] The two mutually perpendicular sides of the rectangular cross section of the shell correspond to the X-axis and the Y-axis respectively.

[0016] Thus, the desired noise reduction effect can be achieved with lower cost and simpler structure.

[0017] Further, the first straight section has a first vertex at the first port, and the first vertex is at the center of the first port, so that the air duct uniformly discharges air from the first port.

[0018] Further, the tangent directions of the end points of the first curved section and the second curved section respectively extend along the Y axis, so that smooth transition with the first straight section can be ensured.

[0019] Further, the angles between the tangent lines passing through the two end points of the first curved section and the connecting line between the two end points are equal, and the angles between the tangent lines passing through the two end points of the second curved section and the connecting line between the two end points are equal, so that lower flow resistance can be achieved.

[0020] Further, the second air duct inner surface includes a first wall surface and a second wall surface, and in any cross section perpendicular to the thickness direction of the shell, the first wall surface is composed of a second straight section and a third curved section, and the second wall surface is composed of a third straight section and a fourth curved section, the second straight section has a second vertex, and the third straight section has a third vertex, and the second vertex and the third vertex are respectively located at opposite edges of the second port.

[0021] Further, the dividing point of the second straight section and the third curved section is a first dividing point, and the dividing point of the third straight section and the fourth curved section is a second dividing point, and each dividing point is a tangent point where the corresponding straight section and curved section are tangent to each other.

[0022] The projection of the first dividing point on the first wall surface on the edge where the first port is located is closer to the third vertex than the second vertex, and the projection of the second dividing point on the second wall surface on the edge where the first port is located is closer to the second vertex than the third vertex, so as to ensure that noise cannot directly pass out.

[0023] Further, the first straight section has a first vertex at the first port, a first auxiliary line is made, the first auxiliary line intersects the first vertex of the first straight section and the starting point of the first curved section away from the first straight section, a second auxiliary line is made, the second auxiliary line intersects the first vertex of the first straight section and the starting point of the second curved section away from the first straight section, a slanted line is made from the second vertex, the slanted line is inclined by 8° with respect to the Y axis and intersects the first auxiliary line, and the intersection point is the first dividing point, a slanted line is made from the third vertex, the slanted line is inclined by 8° with respect to the Y axis and intersects the second auxiliary line, and the intersection point is the second dividing point, and the connecting line of the first dividing point and the second dividing point intersects the first air duct inner surface at the bottom end point of the first straight section away from the first port. 8° is the expansion angle of the air duct, so that the maximum outlet area and the lowest outlet flow rate can be achieved without separation.

[0024] Preferably, to facilitate the fluid entering the air duct, the sound attenuation device further has two second ports as air inlets, one of which is located between the starting point of the inner surface of one of the second air ducts away from the second port and the starting point of the first curved section away from the first straight section, and the other of which is located between the starting point of the inner surface of the other of the second air ducts away from the second port and the starting point of the second curved section away from the first straight section.

[0025] Further, the cross-sectional area of the air duct portion between the first curved section and the third curved section monotonously decreases first and then monotonously increases from the second port to the first port, and the minimum cross-sectional area is located at the position of the first demarcation point.

[0026] The cross-sectional area of the air duct portion between the second curved section and the fourth curved section monotonously decreases first and then monotonously increases from the second port to the first port, and the minimum cross-sectional area is located at the position of the second demarcation point.

[0027] Thus, it is ensured that the air duct does not expand when turning (corresponding to the curved section) and does not turn when expanding (corresponding to the straight section), and separation in the air duct is avoided.

[0028] Preferably, to facilitate the fluid entering the air duct, the sound attenuation device further has two second ports as air inlets, one of which is located between the starting point of the inner surface of one of the second air ducts away from the second port and the starting point of the first curved section away from the first straight section, and the other of which is located between the starting point of the inner surface of the other of the second air ducts away from the second port and the starting point of the second curved section away from the first straight section.

[0029] Further, to facilitate the air flow being discharged rapidly, in any cross section perpendicular to the thickness direction of the shell, the total length of the edge of the shell coinciding with the first port is W1, the width of the first port itself is W2, and W2≥0.5W1 is satisfied.

[0030] The application solves the second technical problem by adopting the technical scheme of an electric appliance characterized by application of the sound attenuation device as described above, the sound attenuation device being arranged between the air inlet of the electric appliance and the power component, and the first port facing the air inlet of the electric appliance.

[0031] Preferably, the electric appliance is a water heater.

[0032] Compared with the prior art, the application has the advantage that sound waves emitted from the first port in any direction will be reflected at least once on the sound-absorbing wall before being emitted from the air inlet, instead of being directly emitted from the air inlet, and the rigid wall increases the number of sound wave reflections, so that the sound waves collide with the inner surface of the first air duct more times, further reducing the noise. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 A schematic diagram of the muffling device of the first embodiment of the present application;

[0034] Figure 2 A schematic diagram of the actual processing of the muffling device of the first embodiment of the present application;

[0035] Figure 3 A schematic diagram of the muffling device of the first embodiment of the present application (showing the change in cross-sectional area);

[0036] Figure 4 A schematic diagram of the muffling device of the second embodiment of the present application. DETAILED DESCRIPTION

[0037] The present application will be further described in detail below with reference to the accompanying drawings.

[0038] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, since the disclosed embodiments of the present application can be arranged in different directions, so these directional terms are only illustrative and should not be regarded as limiting, such as "upper", "lower" do not necessarily mean opposite or consistent with the direction of gravity. In addition, the features defined as "first", "second" can be explicitly or implicitly included one or more features.

[0039] Embodiment One

[0040] Referring to Figures 1 to 3 A muffling device, generally used in electrical appliances, mainly household appliances, is arranged between the air inlet and the power component of the electrical appliance. The muffling device comprises a hollow shell 1, the cross section of the shell 1 is rectangular, two mutually perpendicular edges of the rectangular cross section correspond to the X-axis and the Y-axis respectively, such as the width direction of the rectangle is along the X-axis direction, the length direction of the rectangle is along the Y-axis direction, and the X-axis and the Y-axis are perpendicular to each other. The cross section is any parallel paper plane shown in the figure. It can be mainly used for low-resistance sound-absorbing air inlet of the back side (wall side) of a gas water heater, and can also be used universally for other scenes with a rectangular edge or part of an edge as an air outlet. Figure 1

[0041] ​Unless otherwise specified, the following describes the characteristics in any one of the above cross sections. One edge of the housing 1 is provided with the first port 12 as an air outlet, and the noise of the power unit is transmitted into the housing 1 from the first port 12. The total length of the edge of the housing 1 coinciding with the first port 12 (the dimension along the Y axis) is Wl, the width of the first port 12 itself (the dimension along the Y axis) is W2, and the following is satisfied: W2≥0.5Wl, and more preferably, W2≥0.7Wl, so that the air flow is rapidly discharged. The midpoint of the edge of the housing 1 coinciding with the first port 12 is Al, the midpoint of the first port 12 along the edge is A2, the distance between Al and A2 is W3, and W3≤0.15Wl, that is, the first port 12 is located substantially in the middle of the edge of the housing 1 without greatly deviating toward one end.

[0042] All parts of the housing 1 except the second port 12 can be freely provided with an air inlet for the air flow, and the meaning of the freedom here is the freedom of length and position.

[0043] The space in the housing 1 is provided with the first sound absorbing material 2 and the rigid wall 31, and the space in the housing 1 is also provided with the rigid wall 31, the sound absorbing effect of which can be ignored, which is usually formed of sheet metal or plastic slats, and when it is used for a water heater, it can also be formed of a sheet metal profile of the back plate of a gas water heater. The first sound absorbing material 2 and the rigid wall 31 together constitute an air duct Q, the first sound absorbing material 2 constitutes the inner wall surface of the air duct Q, which is the first air duct inner surface 21, and it is also a sound absorbing wall surface, and the rigid wall 31 constitutes the second air duct inner surface. The first air duct inner surface 21 and the second air duct inner surface constitute all the wall surfaces of the air duct Q.

[0044] In the present embodiment, the first sound absorbing material 2 is in a substantially “human” shape, and preferably two sound absorbing cotton strips of the same thickness are used to form this shape. The sound absorbing cotton strip is a standard part, and a mold does not need to be made, which can reduce the processing cost. The first air duct inner surface 21 (cross section) of the first sound absorbing material 2 includes a first straight section 211, a first curved section 212, and a second curved section 213. The first straight section 211 extends into the housing 1 along the Y axis direction (not considering processing errors and deformation, etc.) from the first port 12, and the first straight section 211 has a first vertex 2111 at the first port 12, which is located at the center A2 of the first port 12. The first curved section 212 and the second curved section 213 are circular arcs or spline curves.

[0045] The starting point 2122 of the first curved segment 212 and the starting point 2132 of the second curved segment 213 are located on the edge of the shell 1 opposite to the first port 12, and the two starting points are located on opposite ends of the edge, i.e. the corners of the rectangular space. The ending points of the first curved segment 212 and the second curved segment 213 are connected to the end of the first straight segment 211 away from the first port 12. The tangent directions of the respective ending points of the first curved segment 212 and the second curved segment 213 extend along the Y axis, so as to smoothly transition with the first straight segment 211. Preferably, the tangent lines passing through the two ending points of the first curved segment 212 are equal to the included angle between the two ending points, i.e. α21=α22; the tangent lines passing through the two ending points of the second curved segment 213 are equal to the included angle between the two ending points, i.e. α31=α32.

[0046] In actual processing, preferably, one complete sound-absorbing cotton strip is used to form the first stroke of the "person" shape, and another is used to form the second stroke of the "person" shape. The junction of the first stroke and the second stroke can have a little roughness (here, the junction is located on the concave surface of the corner of the flow channel, and the airflow is not easy to separate, so the roughness is acceptable). Therefore, the connection between the two curved segments and the first straight segment 211 allows for a rough transition, such as a gap or a cross.

[0047] The starting point of the rigid wall surface 31 is located on the edge adjacent to the edge of the shell 1 having the first port 12, and the ending point of the rigid wall surface 31 is located on the edge of the first port 12. In this embodiment, the rigid wall surface 31 includes a first wall surface 311 and a second wall surface 312, which are oppositely arranged along the X axis, and the ending points of the two rigid wall surfaces are located on the opposite edges of the first port 12, and the first straight segment 211 is located between the first wall surface 311 and the second wall surface 312. The first wall surface 311 is composed of a second straight segment 313 and a third curved segment 314; the second wall surface 312 is composed of a third straight segment 315 and a fourth curved segment 316. The ending point of the rigid wall surface 31 refers to the point where each straight segment coincides with the edge of the first port 12, i.e. the second vertex 3131 of the second straight segment 313 and the third vertex 3151 of the third straight segment 315.

[0048] The dividing point of the second straight segment 313 and the third curved segment 314 is a first dividing point 3132, and the dividing point of the third straight segment 315 and the fourth curved segment 316 is a second dividing point 3152, and each dividing point is also a tangent point where the corresponding straight segment and curved segment are tangent to each other. The third curved segment 314 and the fourth curved segment 316 can be a circular arc, a quadratic curve or a cubic spline curve.

[0049] The projection of the first dividing point 3132 on the first wall surface 311 on the edge of the first port 12 is closer to the third vertex 3151 than the second vertex 3131, Figure 1The projection of the first demarcation point 3132 on the edge where the first port 12 is located is on the right side of the second vertex 3131, as shown in FIG. 13. Similarly, the projection of the second demarcation point 3152 on the edge where the first port 12 is located is closer to the second vertex 3152 than to the third vertex 3151, as shown in FIG. 14. Figure 1 The projection of the second demarcation point 3152 on the edge where the first port 12 is located is on the left side of the third vertex 3151, as shown in FIG. 14.

[0050] In this embodiment, there are also two second ports 11 as air inlets, which are located on the two edges adjacent to the first port 12 of the rectangle and are located on the respective edges away from the end of the second port 11. As shown in FIG. 12, Figure 1 As shown in FIG. 12, the first port 12 is located at the top, and the second port 11 is located at the left and right sides close to the bottom. One of the second ports 11 is located between the starting point of one of the rigid wall surfaces 31 and the starting point of the first curved section 212, and the other first port 11 is located between the starting point of the other rigid wall surface 31 and the starting point of the second curved section 213.

[0051] As shown in FIG. 12, Figure 1 All straight lines 121 intersecting the first port 12 (representing the direction of sound wave propagation) will intersect the sound-absorbing first duct inner surface 21 of the first sound-absorbing material 2 at least once, so that the sound wave is directly absorbed by the surface of the first sound-absorbing material 2 or is reflected on the rigid wall surface 31 and then intersects the first duct inner surface 21 at least once.

[0052] A first auxiliary line 41 is drawn to intersect the first vertex 2111 of the first straight section 211 and the starting point 2122 of the first curved section 212, and a second auxiliary line 42 is also drawn to intersect the first vertex 2111 of the first straight section 211 and the starting point 2132 of the second curved section 213. A slant line is drawn from the second vertex 3131 to intersect the first auxiliary line 41 at an angle of 8° with respect to the Y axis, and the intersection point is the first demarcation point 3132. A slant line is drawn from the third vertex 3151 to intersect the second auxiliary line 42 at an angle of 8° with respect to the Y axis, and the intersection point is the second demarcation point 3152.

[0053] The intersection point of the line connecting the first demarcation point 3132 and the second demarcation point 3152 and the first duct inner surface 21 is the bottom end point 2112 of the first straight section 211 away from the first port 12.

[0054] The third curved section 314 and the fourth curved section 316 can be circular arcs, quadratic curves or cubic curves, and the specific shape is not limited.

[0055] Referring to Figure 3Arrow P indicates the direction of fluid flow. The shapes of the wall or solid sections 212, 213, 314, and 316 must ensure that... Figure 3 In the left and right channels shown, the flow cross-sectional area (a cross-section refers to any cross-section perpendicular to the thickness direction of the outer shell 1, and the cross-sectional area is measured by the diameter of the inscribed circle; only the left channel is shown, and the inscribed circles M1, M2, and M3 represent the inscribed circles of the three cross-sections of the left channel; the same applies to the right channel) first monotonically decreases and then monotonically increases (the derivative changes monotonically) from the second port 11 to the first port 12. The throats of the two flow channels (the positions with the smallest flow cross-sectional area) are located precisely at the first boundary point 3132 and the second boundary point 3152.

[0056] When the silencing device of the present invention is applied to a water heater, in order to ensure the stability of the sound-absorbing cotton and its sound absorption effect, the thickness of the first straight segment 211, the first curved segment 212 and the second curved segment 213 is ( Figure 1 The dimensions shown in the left and right directions are all recommended to be no less than 1cm.

[0057] Example 2

[0058] See Figure 4 In this embodiment, unlike the first embodiment described above, a second sound-absorbing material 5 is provided, and the inner surface of the second air duct is formed by the surface (sound-absorbing wall) of the second sound-absorbing material 5. At this time, the straight line 121 can intersect with or be intersected by the inner surface of the first air duct.

[0059] In this invention, the fan speed of the water heater can be intelligently controlled by voice. Therefore, the water heater can be equipped with an intelligent voice control module, which includes a controller, a voice receiving module, and a voice parsing module. The voice receiving module can receive user commands, and the voice parsing module can parse the commands and control the water heater to perform corresponding operations based on the parsed commands, thereby achieving intelligent regulation of the water heater and improving the user experience. Of course, the dimensions of the aforementioned air duct Q and the dimensions of the sound-absorbing material still need to meet the operating conditions under intelligent regulation.

[0060] When a sound flow control silencing device is applied to other electrical appliances, those appliances can also be intelligent control appliances.

Claims

1. A muffling device comprising a hollow shell (1), the cross section of the shell (1) being rectangular, the cross section being any cross section perpendicular to the thickness direction of the shell (1); characterized in that: the space inside the shell (1) is provided with a first duct inner surface (21) and a second duct inner surface, the first duct inner surface being an absorbing wall surface, the space between the first duct inner surface (21) and the second duct inner surface constituting a duct (Q), the first duct inner surface (21) and the second duct inner surface constituting all the walls of the duct (Q), the second duct inner surface being a rigid wall surface or an absorbing wall surface; in any cross section perpendicular to the thickness direction of the shell (1), one side of the shell (1) is provided with a first port (12) as an air outlet and capable of allowing noise sound waves to enter, any straight line (121) intersecting the first port (12) being: when the second duct inner surface is a rigid wall surface, the straight line (121) intersects the first duct inner surface (21) at least once, or intersects the first duct inner surface (21) at least once after being reflected on the second duct inner surface; when the second duct inner surface is an absorbing wall surface, the straight line (121) intersects the first duct inner surface (21) or the second duct inner surface at least once.

2. The muffling device of claim 1, wherein: The second duct inner surface has two, oppositely arranged along the X-axis direction; in any cross section perpendicular to the thickness direction of the shell (1), the first duct inner surface (21) comprises a first straight line segment (211), a first curved segment (212) and a second curved segment (213), the first straight line segment (211) extending from the first port (12) into the shell (1) along the Y-axis direction, the first curved segment (212) and the second curved segment (213) each having an end point connected to the bottom end point (2112) of the first straight line segment (211) away from the first port (12), the first straight line segment (211) being located between the two second duct inner surfaces; the two mutually perpendicular sides of the rectangular cross section of the shell (1) correspond to the X-axis and the Y-axis respectively.

3. The muffling device of claim 2, wherein: The first straight line segment (211) has a first vertex (2111) at the first port (12), the first vertex (2111) being located at the center (A2) of the first port (12).

4. The muffling device of claim 2, wherein: The tangent directions of the end points of the first curved segment (212) and the second curved segment (213) each extend along the Y-axis.

5. The muffling device of claim 4, wherein: The tangent lines passing through the two end points of the first curved segment (212) each make an equal angle with the line segment connecting the two end points, and the tangent lines passing through the two end points of the second curved segment (213) each make an equal angle with the line segment connecting the two end points.

6. The muffling device of claim 2, wherein: The second air duct inner surface comprises a first wall surface (311) and a second wall surface (312), in any section perpendicular to the thickness direction of the shell (1), the first wall surface (311) is composed of a second straight line segment (313) and a third curved segment (314), the second wall surface (312) is composed of a third straight line segment (315) and a fourth curved segment (316), the second straight line segment (313) has a second vertex (3131), the third straight line segment (315) has a third vertex (3151), and the second vertex (3131) and the third vertex (3151) are located on opposite edges of the second port (12) respectively.

7. The muffling device of claim 6, wherein: The junction point of the second straight line segment (313) and the third curved segment (314) is a first junction point (3132), and the junction point of the third straight line segment (315) and the fourth curved segment (316) is a second junction point (3152), each junction point is a tangent point where the corresponding straight line segment and the curved segment are tangent to each other. The projection of the first junction point (3132) on the edge where the first port (12) is located on the first wall surface (311) is closer to the third vertex (3151) than the second vertex (3131), and the projection of the second junction point (3152) on the edge where the first port (12) is located on the second wall surface (312) is closer to the second vertex (3152) than the third vertex (3151).

8. The muffling device of claim 7, wherein: The first straight line segment (211) has a first vertex (2111) at the first port (12), a first auxiliary line (41) is drawn, the first auxiliary line (41) intersects the first vertex (2111) of the first straight line segment (211) and the starting point (2122) of the first curved segment (212) away from the first straight line segment (211), a second auxiliary line (42) is drawn, the second auxiliary line (42) intersects the first vertex (2111) of the first straight line segment (211) and the starting point (2132) of the second curved segment (213) away from the first straight line segment (211), a slanted line is drawn from the second vertex (3131) and inclined 8° relative to the Y axis and intersects the first auxiliary line (41), and the intersection point is the first junction point (3132), a slanted line is drawn from the third vertex (3151) and inclined 8° relative to the Y axis and intersects the second auxiliary line (42), and the intersection point is the second junction point (3152), and the intersection point of the line connecting the first junction point (3132) and the second junction point (3152) and the first air duct inner surface (21) is the bottom end point (2112) of the first straight line segment (211) away from the first port (12).

9. The muffling device of claim 7, wherein: The muffling device also has two second ports (11) as air inlets, one of which is located between the starting point of the inner surface of one of the second air ducts away from the second port (12) and the starting point of the first curved section (212) away from the first straight section (211), and the other first port (11) is located between the starting point of the inner surface of the other second air duct away from the second port (12) and the starting point of the second curved section (213) away from the first straight section (211).

10. The muffling device of claim 9, wherein: The cross-sectional area of the air duct (Q) part between the first curved section (212) and the third curved section (314) decreases monotonically first and then increases monotonically from the second port (11) to the first port (12), and the minimum cross-sectional area is located at the position of the first demarcation point (3132); The cross-sectional area of the air duct (Q) part between the second curved section (213) and the fourth curved section (316) decreases monotonically first and then increases monotonically from the second port (11) to the first port (12), and the minimum cross-sectional area is located at the position of the second demarcation point (3152).

11. The muffling device of claim 6, wherein: The muffling device also has two second ports (11) as air inlets, one of which is located between the starting point of the inner surface of one of the second air ducts away from the second port (12) and the starting point of the first curved section (212) away from the first straight section (211), and the other first port (11) is located between the starting point of the inner surface of the other second air duct away from the second port (12) and the starting point of the second curved section (213) away from the first straight section (211).

12. The muffling device according to any one of claims 1 to 11, characterized in that: On any cross section perpendicular to the thickness direction of the shell (1), the total edge length of the edge of the shell (1) coinciding with the first port (12) is W1, and the width of the first port (12) itself is W2, and W2≥0.5W1 is satisfied.

13. An electrical appliance characterized by: The application has the muffling device as claimed in any one of claims 1-12, which is arranged between the air inlet of the electric appliance and the power component, and the first port (12) faces the air inlet of the electric appliance.

14. The appliance of claim 13, wherein: The electric appliance is a water heater. The electric appliance is a water heater.

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