A green building roof heat insulation plate

Abstract

The application provides a green building roof heat insulation plate and relates to the technical field of roof heat insulation plates.The green building roof heat insulation plate comprises a heat insulation block body, a heat insulation circulating channel in a continuous curved structure is arranged in the heat insulation block body, and a heat insulation circulating pipeline matched with the structure size of the heat insulation circulating channel is arranged in the heat insulation circulating channel.The heat insulation block body has basic heat insulation and heat resistance, the continuous curved structure heat insulation circulating channel arranged in the heat insulation block body is matched with the heat insulation circulating pipeline, a main heat insulation core structure is formed, sufficient heat exchange can be formed between the heat insulation block body and the heat insulation circulating pipeline after cooling medium is introduced, the solar radiation heat and the environmental heat absorbed by the roof are continuously absorbed and led to the outdoor, the heat transfer to the indoor is reduced from the source, the heat insulation efficiency is greatly improved compared with the traditional passive heat insulation plate, and the problem that the heat insulation effect is attenuated due to easy heat accumulation under high temperature because the building roof heat insulation plates on the market only have single passive heat insulation function and no active heat exhaust structure.

Description

Technical Field

[0001] This invention relates to the field of roof insulation technology, and more particularly to a green building roof insulation panel. Background Technology

[0002] With the rapid development of the green building industry, building energy conservation and living environment comfort have become core requirements for building design and construction. As the main part of the building for heat exchange and noise transmission with the outside environment, the roof's heat insulation, sound insulation and waterproofing performance directly affect the building's energy efficiency and indoor living experience. Therefore, the comprehensive performance requirements for roof insulation components are constantly increasing.

[0003] Currently, most building roof insulation panels on the market mainly have a single passive insulation function. Their insulation principle relies solely on the heat-insulating properties of the insulation material itself to block heat transfer, without an active heat dissipation structure design. In the high-temperature and strong radiation environment of summer, the insulation panel easily absorbs and accumulates a large amount of heat, and the insulation effect decays rapidly as the temperature rises. It is difficult to effectively prevent heat from being conducted into the room, resulting in a significant increase in the energy consumption of indoor air conditioning, which does not conform to the energy-saving concept of green building.

[0004] Meanwhile, existing roof insulation panels generally suffer from limited functionality. Most products lack professional sound insulation and sound absorption structures, failing to effectively block external wind and rain noise, high-altitude traffic noise, and ambient noise from the building's surroundings. They also cannot reduce the transmission of indoor noise through the roof, easily leading to a poor indoor acoustic environment. A few insulation panels that also offer sound insulation have flawed sound absorption structure designs. The sound absorption components are often directly attached to the inner wall of the sound absorption groove, easily resulting in solid-borne sound transmission. Furthermore, the sound absorption cavity structure is simple, only achieving simple sound wave reflection and failing to effectively attenuate sound wave energy, significantly reducing the sound insulation and sound absorption effect. Summary of the Invention

[0005] This invention relates to a green building roof insulation board, which solves the problems of current building roof insulation boards on the market that mostly have only a single passive heat insulation function, lack an active heat dissipation structure, are prone to heat accumulation at high temperatures leading to a decrease in heat insulation effect, generally have single function, lack professional sound insulation and sound absorption design, and the few that also have sound insulation have structural defects and poor sound insulation and sound absorption effects.

[0006] This invention provides a green building roof insulation panel, specifically comprising: an insulation block, the insulation block having a square block structure, a U-shaped groove for receiving the insulation block at the junction of its front and right ends, and a groove for receiving the insulation block at the junction of its rear and left ends; an insulation circulation channel with a continuously curved structure inside the insulation block, the two opening ends of the insulation circulation channel being connected to the two grooves respectively, and the opening ends corresponding to the axial center of the semi-circular structure of the grooves; an insulation circulation pipe matching its structural dimensions installed inside the insulation circulation channel, with a connector fixedly installed at both ends of the insulation circulation pipe via a corrugated flexible hose, the connector and the corrugated flexible hose being received inside the groove.

[0007] Furthermore, a vapor barrier layer is fixedly bonded to the top surface of the heat insulation block, and a waterproof layer is fixedly bonded to the top surface of the vapor barrier layer.

[0008] Furthermore, an upper sound insulation block is fixedly bonded to the bottom end face of the heat insulation block. The upper sound insulation block has a square block structure, and its side length is consistent with that of the heat insulation block. A buckle is fixedly installed on each of the four side end faces adjacent to the bottom end face of the upper sound insulation block.

[0009] Furthermore, a lower sound insulation block is provided below the upper sound insulation block, and the structural dimensions of the lower sound insulation block are consistent with those of the upper sound insulation block; a snap-fit ​​groove is provided on the top surface of the lower sound insulation block adjacent to the four side end faces; when the four snap-fits are engaged with the four snap-fit ​​grooves respectively, the bottom end face of the upper sound insulation block and the top end face of the lower sound insulation block are in close contact.

[0010] Furthermore, the bottom surface of the upper sound insulation block has several upper sound-absorbing grooves evenly distributed, and the upper sound-absorbing grooves have a hemispherical groove structure; the top surface of the lower sound insulation block has several lower sound-absorbing grooves evenly distributed, and the structural dimensions of the lower sound-absorbing grooves are consistent with the structural dimensions of the upper sound-absorbing grooves.

[0011] Furthermore, when the four buckles are engaged with the four buckle slots respectively, the upper sound-absorbing groove and the lower sound-absorbing groove are positioned accordingly, together forming a complete spherical cavity.

[0012] Furthermore, each of the lower sound-absorbing grooves has four support rods fixedly installed in a ring array on its inner circumference, and the support rods do not extend beyond the interior of the lower sound-absorbing groove.

[0013] Furthermore, each of the lower sound-absorbing grooves contains a sound-absorbing component, which is a cotton ball. The diameter of the sound-absorbing component is smaller than the diameter of the lower sound-absorbing groove. The sound-absorbing component is inserted into the support rod. When the four buckles are engaged with the four buckle slots respectively, the sound-absorbing component does not contact the inner circumferential surface of the lower sound-absorbing groove or the inner circumferential surface of the upper sound-absorbing groove.

[0014] This invention provides a green building roof insulation panel with the following beneficial effects: The thermal insulation block of this invention possesses basic thermal insulation and heat-resistant properties. Its internally formed continuous curved thermal insulation circulation channel, combined with thermal insulation circulation pipes, constitutes an active thermal insulation core structure. The curved structure significantly increases the contact area between the pipes and the thermal insulation block. After the cooling medium is introduced, it can form a sufficient heat exchange with the thermal insulation block, continuously absorbing solar radiation heat and ambient heat absorbed by the roof and expelling it outdoors, reducing heat transfer to the interior from the source. Compared with traditional passive thermal insulation panels, the thermal insulation efficiency is greatly improved. At the same time, adjacent thermal insulation panels can be connected by connectors to form an integrated roof circulation pipeline, adapting to roofs of different areas and achieving uniform thermal insulation throughout the entire area.

[0015] The present invention forms an integrated solid sound insulation layer by snapping together upper and lower sound insulation blocks below the heat insulation block, effectively cutting off the solid transmission path of wind and rain noise, traffic noise, etc. through the roof, and achieving basic sound insulation. After the upper and lower sound insulation blocks are snapped together, the complete spherical cavity formed by the hemispherical sound absorption groove can cause the incoming noise sound waves to be reflected multiple times, achieving initial energy attenuation. In conjunction with the cotton ball sound absorption component suspended and fixed in the cavity, the porous structure of the cotton ball is used to absorb the sound waves at a secondary depth. Moreover, the sound absorption component is suspended by the support rod and does not contact the groove, avoiding solid-borne sound transmission. The dual sound absorption design greatly improves the noise attenuation effect, taking into account the sound insulation and sound absorption needs of the roof.

[0016] The present invention features a vapor barrier layer and a waterproof layer sequentially arranged on the top of the insulation block, forming a closed-loop waterproof and vapor barrier protection system: the waterproof layer, as the first layer of protection on the outside, effectively blocks the penetration of liquid water such as rainwater and dew, preventing corrosion of the insulation circulation pipe and deformation of the insulation block due to moisture; the vapor barrier layer prevents indoor and outdoor water vapor from penetrating into the interior of the insulation block, avoiding the condensation of water vapor into liquid water in the insulation circulation channel, and preventing the reduction of the insulation effect due to additional heat conduction caused by water vapor condensation. The double-layer structure fundamentally solves the problem that traditional insulation boards are prone to heat insulation performance degradation and structural damage due to moisture, and greatly improves the durability and heat insulation performance stability of the insulation board.

[0017] The thermal insulation panel of this invention adopts a square modular structure, which can meet the seamless splicing and laying requirements of various building roofs. The corrugated hose of the thermal insulation circulation pipe is flexible and can accommodate slight positional deviations during splicing, ensuring the sealing and flexibility of the pipeline connection. Moreover, the connector and the corrugated hose are stored in the storage notch, which does not affect the splicing and bonding of adjacent thermal insulation panels. The upper and lower sound insulation blocks are precisely connected by snap-fit ​​and snap-fit ​​groove. The assembly process does not require additional complex fasteners, resulting in high installation efficiency and enabling rapid construction and laying of roofs.

[0018] The modular structural design of this invention makes the later maintenance of the insulation panel more convenient. When a single insulation block, sound insulation block, or insulation circulation pipe is damaged, it can be disassembled and replaced individually without the need to completely remove the roof insulation panel structure, which greatly reduces the later maintenance and replacement costs. At the same time, all components are standardized in design, which can realize mass production and recycling. The sound-absorbing components use environmentally friendly materials such as cotton balls, which release no harmful components. The overall design is in line with the core concepts of green building energy conservation, environmental protection, recyclability, and easy maintenance. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings of the embodiments will be briefly described below.

[0020] The accompanying drawings described below are only related to some embodiments of the invention and are not intended to limit the invention.

[0021] In the attached diagram: Figure 1 A schematic diagram of the isometric structure of the present invention is shown; Figure 2 A schematic diagram of the top isometric structure of the present invention in its split state is shown; Figure 3 The present invention is shown Figure 2 A magnified view of the structure at point A in the middle; Figure 4 The present invention is shown Figure 2 A magnified schematic diagram of the structure at point B in the middle; Figure 5 A schematic diagram of the bottom isometric structure of the present invention in its split state is shown. Figure 6 The present invention is shown Figure 5 A magnified schematic diagram of the structure at point C in the middle; Figure 7 A schematic diagram of the main structure of the present invention is shown; Figure 8 The present invention is shown Figure 7 Schematic diagram of the cross-sectional structure of the middle DD; Figure 9 The present invention is shown Figure 8Schematic diagram of the structure with the central insulation circulation pipe removed; Figure 10 A cross-sectional structural schematic diagram of the present invention is shown; Figure 11 The present invention is shown Figure 10 A magnified schematic diagram of the structure at point E in the middle; List of reference numerals 1. Thermal insulation block; 101. Storage notch; 102. Thermal insulation circulation channel; 2. Vapor barrier layer; 3. Waterproof layer; 4. Upper sound insulation block; 401. Clip; 402. Upper sound absorption groove; 5. Lower sound insulation block; 501. Clip groove; 502. Lower sound absorption groove; 503. Support rod; 6. Thermal insulation circulation pipe; 601. Corrugated flexible hose; 602. Connector; 7. Sound absorption assembly. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the described embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] Example: Please refer to Figures 1 to 11 : This invention proposes a green building roof insulation panel, comprising: an insulation block 1, which has a square block structure and serves as the core load-bearing foundation of the overall insulation panel, adapting to the modular installation requirements of roofs and possessing basic thermal insulation performance; a U-shaped groove 101 is provided at the junction of the front and right ends of the insulation block 1, and a similar groove 101 is provided at the junction of the rear and left ends of the insulation block 1; the grooves 101 are used to conceal and store the corrugated hose 601 and connector 602, preventing them from being exposed to environmental factors and adapting to the space requirements for pipe connections; and a continuously curved insulation layer is provided inside the insulation block 1. The circulation channel 102 has a curved structure that increases the contact area between the pipe and the insulation block 1. The two open ends of the insulation circulation channel 102 are connected to two receiving slots 101, and the positions of its open ends correspond to the central part of the semi-circular structure of the receiving slots 101. An insulation circulation pipe 6 that matches its structural dimensions is installed inside the insulation circulation channel 102. The insulation circulation pipe 6 is the core component of active insulation and can be circulated with cooling medium to achieve heat exchange and heat dissipation. Both ends of the insulation circulation pipe 6 are fixedly installed with a connector 602 through a corrugated hose 601. The connector 602 and the corrugated hose 601 are stored inside the receiving slots 101.

[0024] Among them, a vapor barrier layer 2 is fixedly bonded to the top surface of the heat insulation block 1. The vapor barrier layer 2 can effectively prevent indoor and outdoor water vapor from penetrating into the interior of the heat insulation block 1, and avoid water vapor condensation affecting the heat insulation performance. A waterproof layer 3 is fixedly bonded to the top surface of the vapor barrier layer 2. As the first layer of protection on the outside, the waterproof layer 3 can block rainwater, dew and other liquid water from penetrating and protect the internal structures from water immersion damage.

[0025] Among them, the bottom end face of the heat insulation block 1 is fixedly bonded to the upper sound insulation block 4. The upper sound insulation block 4 has a square block structure, and its side length is consistent with the side length of the heat insulation block 1, so as to ensure the overall structural regularity and splicing compatibility. A buckle 401 is fixedly installed on the bottom end face of the upper sound insulation block 4 adjacent to the four side end faces.

[0026] The upper sound insulation block 4 is provided with a lower sound insulation block 5 below it. The structural dimensions of the lower sound insulation block 5 are consistent with those of the upper sound insulation block 4. A snap-fit ​​groove 501 is provided on the top surface of the lower sound insulation block 5 adjacent to the four side end surfaces. The snap-fit ​​groove 501 and the snap-fit ​​401 are precisely matched to ensure the fastening is firm. When the four snap-fit ​​401 are fastened and engaged with the four snap-fit ​​grooves 501 respectively, the bottom end surface of the upper sound insulation block 4 and the top end surface of the lower sound insulation block 5 are in close contact.

[0027] Among them, the bottom surface of the upper sound insulation block 4 has several upper sound absorption grooves 402 evenly distributed, and the upper sound absorption grooves 402 have a hemispherical groove structure; the top surface of the lower sound insulation block 5 has several lower sound absorption grooves 502 evenly distributed, and the structural dimensions of the lower sound absorption grooves 502 are consistent with the structural dimensions of the upper sound absorption grooves 402. The upper and lower sound absorption grooves provide a structural basis for forming a spherical sound absorption cavity, and the evenly distributed design can achieve full-area sound absorption.

[0028] When the four buckles 401 are engaged with the four buckle slots 501 respectively, the upper sound-absorbing groove 402 and the lower sound-absorbing groove 502 are positioned correspondingly, and together they form a complete spherical cavity. The spherical cavity can cause the incoming noise sound waves to be reflected multiple times, thus achieving the initial attenuation of sound wave energy.

[0029] Each of the lower sound-absorbing grooves 502 has four support rods 503 fixedly installed in a ring array on its inner circumferential surface. The support rods 503 do not extend beyond the interior of the lower sound-absorbing grooves 502, thus avoiding the support rods 503 from blocking the reflection and propagation of sound waves in the cavity. The ring array distribution can achieve stable fixation of the sound-absorbing component 7.

[0030] Each of the lower sound-absorbing grooves 502 contains a sound-absorbing component 7, which is a cotton ball. The porous structure of the cotton ball absorbs sound wave energy to achieve deep sound absorption. The diameter of the sound-absorbing component 7 is smaller than the diameter of the lower sound-absorbing groove 502. The sound-absorbing component 7 is inserted into the support rod 503 to ensure the installation stability of the sound-absorbing component 7. When the four buckles 401 are engaged with the four buckle slots 501 respectively, the sound-absorbing component 7 does not contact the inner circumferential surface of the lower sound-absorbing groove 502 or the inner circumferential surface of the upper sound-absorbing groove 402.

[0031] The working principle of this embodiment: The continuous curved structure of the heat insulation circulation channel 102 inside the heat insulation block 1 provides precise installation space for the heat insulation circulation pipe 6. The curved structure greatly extends the laying path of the pipe, maximizing the contact area between the pipe and the heat insulation block 1, laying the foundation for sufficient heat exchange. The heat insulation circulation pipe 6 is sized to match the heat insulation circulation channel 102. Cooling media such as circulating cold water can be introduced into the heat insulation circulation pipe 6. The solar radiation heat received by the roof and the outdoor ambient heat will be transferred to the heat insulation block 1 through heat conduction and heat radiation, forming a temperature difference with the cooling medium in the heat insulation circulation pipe 6. When the medium flows in the heat insulation circulation pipe 6, it will continuously absorb the heat of the heat insulation block 1, complete the heat exchange process, and conduct the absorbed heat to the outside through medium circulation, realizing the active dissipation of roof heat and reducing the transfer of heat to the room from the source. The corrugated hoses 601 and connectors 602 at the beginning and end of the heat insulation circulation pipe 6 provide support for modular splicing. Adjacent heat insulation blocks 1 can be connected to each other through connectors 602, so that the heat insulation circulation pipe 6 forms an integrated roof circulation pipeline, which can adapt to roof layouts of different areas. The corrugated hoses 601 are flexible and can adapt to slight positional deviations during splicing, ensuring the sealing and flexibility of the pipeline connection. At the same time, both connectors 602 and corrugated hoses 601 are housed in the U-shaped storage notch 101 of the heat insulation block 1, which does not affect the splicing and fitting between adjacent heat insulation blocks 1.

[0032] The vapor barrier layer 2 and the waterproof layer 3 at the top of the insulation block 1 form a double-layer protection system. From the two dimensions of external waterproofing and internal vapor barrier, it prevents moisture from intruding and damaging the insulation structure, avoids the decline in insulation performance due to moisture in the structure, and ensures the durability of the overall structure. The waterproof layer 3, as the first layer of protection, effectively blocks rainwater, dew, snow water and other liquid water from penetrating into the interior of the insulation block 1, preventing moisture from entering the insulation circulation channel 102 and causing corrosion of the insulation circulation pipe 6, or soaking the insulation block 1, causing structural deformation and attenuation of insulation performance. The vapor barrier layer 2 is located between the waterproof layer 3 and the insulation block 1, as the second layer of protection. It can effectively block the penetration of indoor and outdoor water vapor, prevent water vapor from condensing into liquid water when it encounters cold in the insulation circulation channel 102 and inside the insulation block 1, and reduce the additional heat conduction caused by water vapor condensation, thus helping to improve the insulation effect. The double-layer structure forms a closed-loop protection of waterproofing and vapor barrier, ensuring the stable operation of the insulation system under various temperature and humidity environments.

[0033] The upper sound insulation block 4 is fixedly bonded to the heat insulation block 1, and the lower sound insulation block 5 is precisely fastened to the upper sound insulation block 4 through the snap fastener 401 and the snap fastener groove 501, forming an integrated solid sound insulation layer. This structure utilizes the principle of solid sound transmission to effectively block the sound of wind and rain outside the roof, high-altitude traffic noise, external building environment noise, and indoor living and equipment noise from being transmitted through the roof structure, cutting off the noise transmission path and achieving basic sound insulation effect. After the upper sound insulation block 4 and the lower sound insulation block 5 are fastened together, the upper hemispherical sound-absorbing groove 402 and the lower hemispherical sound-absorbing groove 502 are precisely aligned to form several independent complete spherical cavities. Combined with the suspended sound-absorbing components 7 inside the cavities, deep attenuation of sound waves is achieved. When noise sound waves enter the spherical cavity, they will be reflected multiple times on the inner wall of the sphere. During the reflection process, the energy of the sound waves will be continuously consumed, achieving the initial attenuation of the sound waves. The four support rods 503 inside the lower sound-absorbing groove 502 suspend and fix the sound-absorbing component 7 in the center of the spherical cavity, and the sound-absorbing component 7 does not contact the inner circumferential surface of the groove, thus avoiding solid-borne sound transmission through the groove; the porous structure of the cotton ball will further absorb the sound wave energy, realizing the secondary attenuation of the sound wave. The design of the support rod 503 ensures the stable position of the sound-absorbing component 7, preventing it from shaking or sticking to the wall of the groove, which would reduce the sound absorption effect. At the same time, it does not affect the reflection and propagation of sound waves in the spherical cavity, thus maximizing the dual sound absorption effect of multiple reflections and porous absorption.

[0034] The insulation panel adopts a square modular structure design. The splicing and cooperation of each component are based on modular laying, which can be seamlessly spliced ​​and laid on the roof. It can adapt to the layout requirements of various building roofs. The modular structure makes later maintenance more convenient. When a single insulation block 1 or the upper sound insulation block 4 and the lower sound insulation block 5 are damaged, they can be disassembled and replaced individually without the need for overall dismantling, reducing maintenance costs and conforming to the design concept of green building energy conservation, environmental protection, recyclability and easy maintenance.

Claims

1. A green building roof insulation panel, characterized in that, include: The heat insulation block (1) has a square block structure. A U-shaped groove (101) is provided at the junction of the front and right ends of the heat insulation block (1), and a storage groove (101) is also provided at the junction of the rear and left ends of the heat insulation block (1). A heat insulation circulation channel (102) with a continuous curved structure is provided inside the heat insulation block (1). The two opening ends of the heat insulation circulation channel (102) are respectively connected to two storage grooves. The notch (101) is connected, and its opening end corresponds to the position of the axial part of the semi-circular structure that receives the notch (101); the heat insulation circulation channel (102) is equipped with a heat insulation circulation pipe (6) that matches its structural size. Both ends of the heat insulation circulation pipe (6) are fixedly installed with a connector (602) through a corrugated hose (601). The connector (602) and the corrugated hose (601) are stored inside the notch (101).

2. The green building roof insulation board according to claim 1, characterized in that, The top surface of the heat insulation block (1) is fixedly bonded with a vapor barrier layer (2), and the top surface of the vapor barrier layer (2) is fixedly bonded with a waterproof layer (3).

3. The green building roof insulation board according to claim 1, characterized in that, The heat insulation block (1) has an upper sound insulation block (4) fixedly bonded to its bottom end face. The upper sound insulation block (4) has a square block structure and its side length is consistent with that of the heat insulation block (1). A buckle (401) is fixedly installed on the bottom end face of the upper sound insulation block (4) adjacent to the four side end faces.

4. A green building roof insulation panel according to claim 3, characterized in that, Below the upper sound insulation block (4) is a lower sound insulation block (5), and the structural dimensions of the lower sound insulation block (5) are consistent with those of the upper sound insulation block (4). The top surface of the lower sound insulation block (5) is provided with a snap-fit ​​groove (501) adjacent to the four side end surfaces. When the four snap-fit ​​grooves (501) are engaged with the four snap-fit ​​grooves (501) respectively, the bottom surface of the upper sound insulation block (4) and the top surface of the lower sound insulation block (5) are in close contact.

5. A green building roof insulation panel according to claim 4, characterized in that, The bottom surface of the upper sound insulation block (4) is provided with several upper sound absorption grooves (402) evenly distributed, and the upper sound absorption grooves (402) are hemispherical groove structures; the top surface of the lower sound insulation block (5) is provided with several lower sound absorption grooves (502) evenly distributed, and the structural dimensions of the lower sound absorption grooves (502) are consistent with the structural dimensions of the upper sound absorption grooves (402).

6. A green building roof insulation panel according to claim 5, characterized in that, When the four buckles (401) are engaged with the four buckle slots (501) respectively, the upper sound-absorbing groove (402) and the lower sound-absorbing groove (502) are in corresponding positions, and together they form a complete spherical cavity.

7. A green building roof insulation panel according to claim 6, characterized in that, Each of the lower sound-absorbing grooves (502) has four support rods (503) fixedly installed in a ring array on its inner circumference. The support rods (503) do not extend beyond the interior of the lower sound-absorbing grooves (502).

8. A green building roof insulation panel according to claim 7, characterized in that, Each of the lower sound-absorbing grooves (502) contains a sound-absorbing component (7), which is a cotton ball. The diameter of the sound-absorbing component (7) is smaller than that of the lower sound-absorbing groove (502). The sound-absorbing component (7) is inserted into the support rod (503). When the four buckles (401) are engaged with the four buckle slots (501), the sound-absorbing component (7) does not contact the inner circumferential surface of the lower sound-absorbing groove (502) and the inner circumferential surface of the upper sound-absorbing groove (402).

Images