Rapid heat dissipation air ring for heating plate

Abstract

The invention provides a rapid heat dissipation air ring for a heating plate, the rapid heat dissipation air ring for the heating plate is sleeved outside the heating plate, the rapid heat dissipation air ring for the heating plate comprises an inner ring and an outer ring, the inner ring comprises a first baffle ring and a second baffle ring, the first baffle ring is provided with an air inlet and an air outlet, the second baffle ring is fixedly connected with the first baffle ring, and the outer ring is fixedly connected with the first baffle ring. The second baffle ring is arranged between the air inlet and the air outlet and divides the first baffle ring into an air inlet side and an air outlet side; the inner ring is sleeved with the outer ring, the outer ring comprises an outer wall and a third baffle ring, the third baffle ring is fixedly connected to the side, close to the heating disc, of the outer wall, the third baffle ring and the second baffle ring are matched with each other to form an air outlet channel, and the air outlet channel is communicated with the air inlet. According to the invention, the gas flow near the upper surface and the lower surface of the heating plate is improved, the cooling rate of the heating plate is improved, the wafer production efficiency is improved, the heat dissipation air ring does not occupy extra vertical space, bidirectional heat dissipation of the upper plate surface and the lower plate surface can be realized, and the heat dissipation efficiency and the economic effect are higher.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to a rapid heat dissipation air ring for a heating plate. Background Art

[0002] In the wafer production process, in order to meet different process requirements, it is often necessary to heat up or cool down the hot plate to a certain temperature. In actual production, the cooling time is much longer than the heating time. Therefore, in order to improve the wafer production efficiency, it is necessary to add an external device to the hot plate system to achieve rapid cooling of the high-temperature hot plate. The existing heating plate cooling methods mainly include natural cooling, cavity exhaust system and hot plate surface direct blowing air system. The cavity exhaust system is to exhaust the larger space outside the hot plate as a whole, and it is difficult to form a large air volume near the surface of the hot plate. The hot plate surface direct blowing air cooling system occupies additional vertical space. The existing method has a low cooling rate and low heat dissipation efficiency, which affects the wafer production efficiency. Summary of the invention

[0003] In view of the above-mentioned problems existing in the prior art, the object of the present invention is to provide a rapid heat dissipation air ring for a heating plate. By arranging mutually interlocking circular rings outside the heating plate, based on the Bernoulli aerodynamic principle, the inlet and outlet air volumes on the upper and lower surfaces of the wafer heating plate are made much larger than the air volume at the air inlet, thereby increasing the gas flow near the upper and lower surfaces of the heating plate, increasing the cooling rate of the hot plate, and improving the wafer production efficiency. The heat dissipation air ring does not occupy additional vertical space, and can realize two-way heat dissipation of the upper and lower plates, thereby achieving higher heat dissipation efficiency and economic effects.

[0004] The technical solution adopted by the present invention is to provide a rapid heat dissipation wind ring for a heating plate, wherein the rapid heat dissipation wind ring of the heating plate is sleeved on the outside of the heating plate, and the rapid heat dissipation wind ring of the heating plate comprises: The inner ring includes a first baffle ring and a second baffle ring, the first baffle ring is provided with an air inlet and an air outlet, the second baffle ring is fixedly connected to the first baffle ring, and the second baffle ring is arranged between the air inlet and the air outlet to separate the first baffle ring into an air inlet side and an air outlet side; The outer ring is sleeved on the outside of the inner ring, and the outer ring includes an outer wall and a third baffle ring. The third baffle ring is fixedly connected to a side of the outer wall close to the heating plate. The third baffle ring and the second baffle ring cooperate with each other to form an air outlet channel, and the air outlet channel is connected to the air inlet.

[0005] Compared with the prior art, the technical effect achieved by adopting this technical scheme is as follows: by arranging an outer ring and an inner ring that cooperate with each other and are sleeved on the outside of the heating plate, an air inlet is arranged on the inner ring, and an air outlet channel is formed by the outer ring and the inner ring. The high-speed airflow entering the air inlet is ejected from the air outlet channel, and a negative pressure is generated on the outer surface of the inner ring, forcing the air above the heating plate to flow along the plate surface into the heat dissipation air circle, and the air flow rate at the upper and lower inlets and outlets of the entire heat dissipation air circle is much larger than the air flow rate of the bottom air inlet, thereby achieving the effect of efficiently cooling the upper and lower surfaces of the heating plate.

[0006] In an optional embodiment, the second retaining ring includes an extension portion and a bending portion, one end of the extension portion is connected to the first retaining ring, the other end of the extension portion is connected to the bending portion, and the bending portion extends in a direction close to the outer wall.

[0007] Compared with the prior art, the technical effect achieved by adopting this technical solution is as follows: by setting an extension portion and a bending portion of the second baffle ring, the bending portion extends toward the direction close to the outer wall, and the bending portion and the extension portion form an air outlet channel with the third baffle ring.

[0008] In an optional embodiment, the extension portion extends in a direction away from the outer wall, and on a radial section of the rapid heat dissipation air ring, the extension portion forms an angle of 70°-80° between the air outlet side and the first baffle ring.

[0009] Compared with the prior art, the technical effect achieved by adopting this technical solution is as follows: an angle of 70°-80° is formed between the extension portion and the first gear ring, which is conducive to accelerating the outflowing gas, forming a greater negative pressure on the outer surface of the inner ring, and inhaling more gas.

[0010] In an optional embodiment, on a radial cross section of the rapid heat dissipation air ring, the bent portion forms an angle of 115°-125° between the air inlet side and the extension portion.

[0011] Compared with the prior art, the technical effect achieved by adopting this technical solution is as follows: an angle of 115°-125° is formed between the bending portion and the extension portion, which is beneficial to increase the flow velocity of the gas when passing through the air outlet channel; the bending portion and the outer wall and the inner wall form an air outlet channel, which can guide the gas to flow out smoothly and concentratedly.

[0012] In an optional embodiment, the diameter of the air inlet on the first baffle ring is smaller than the diameter of the air outlet.

[0013] Compared with the prior art, the technical effect achieved by adopting this technical solution is as follows: the diameter of the air inlet is smaller than the diameter of the air outlet, so that the air inlet and outlet volumes on the upper and lower surfaces of the heating plate are much larger than the air inlet volume, thereby increasing the gas flow near the upper and lower surfaces of the heating plate and accelerating the cooling rate.

[0014] In an optional embodiment, the air outlet channel formed between the second baffle ring and the third baffle ring has a width ranging from 1.10 mm to 1.30 mm.

[0015] Compared with the prior art, the technical effect achieved by adopting this technical solution is as follows: by setting the width range of the air outlet channel formed between the second baffle ring and the third baffle ring to 1.10mm-1.30mm, the airflow is compressed when passing through the narrow area, thereby obtaining a higher outlet speed.

[0016] In an optional embodiment, a ratio of the height of the third retaining ring to the height of the outer wall is 2-2.1.

[0017] Compared with the prior art, the technical effect achieved by adopting this technical solution is as follows: the ratio of the height of the third baffle ring to the height of the outer wall is 2-2.1, and the height design is reasonable. If the height of the outer wall is too high, the structure of the third baffle ring will not be light enough. If the height of the outer wall is too low, the height of the second baffle ring will also be reduced, resulting in insufficient airflow on the outer wall of the second baffle ring, which affects the heat dissipation effect.

[0018] In an optional embodiment, the air inlet is provided in plurality, and the first baffle ring is provided with a partition on the air inlet side, and the partition is used to separate the plurality of air inlets.

[0019] Compared with the prior art, the technical effect achieved by adopting this technical solution is as follows: by arranging partitions between the air inlets of the first baffle ring, the airflows between the air inlets are prevented from interfering with each other, and each air inlet forms an independent air inlet cavity, which is conducive to a smoother and more uniform inflow of airflow.

[0020] In an optional embodiment, an air inlet channel is formed between the third baffle ring and the heating plate, and the air inlet channel is connected to the air outlet.

[0021] Compared with the prior art, the technical effect achieved by adopting this technical solution is as follows: the setting of the air inlet channel is conducive to the flow of gas in and out of the upper and lower surfaces of the heating plate, improves the gas flow near the upper and lower surfaces of the heating plate, and accelerates the heat dissipation efficiency.

[0022] In an optional embodiment, a sealing groove is provided between the outer wall and the third retaining ring.

[0023] Compared with the prior art, the technical effect achieved by adopting this technical solution is that the sealing groove is used to fix the sealing ring to play a sealing role.

[0024] The rapid heat dissipation air ring of the embodiment of the present invention is arranged by arranging an outer ring and an inner ring that cooperate with each other and are arranged outside the heating plate, the inner ring is provided with an air inlet, and the outer ring and the inner ring form an air outlet channel, the high-speed airflow entering the air inlet is ejected from the air outlet channel, and the outer surface of the inner ring generates negative pressure, forcing the air above the heating plate to flow into the heat dissipation air ring along the plate surface, and the inlet and outlet air volumes of the upper and lower surfaces of the entire heating plate are much larger than the air intake flow rate of the air inlet at the bottom of the inner ring, thereby achieving the effect of efficiently cooling the upper and lower surfaces of the heating plate, improving the wafer production efficiency, and the heat dissipation air ring does not occupy additional vertical space, can realize two-way heat dissipation of the upper and lower plates, and has higher heat dissipation efficiency and economic effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 An exploded view of an accelerated heat dissipation air ring provided by an embodiment of the present invention is shown; Figure 2 A schematic diagram of the structure of an outer ring provided by an embodiment of the present invention is shown; Figure 3 A schematic diagram of the structure of the inner ring provided by an embodiment of the present invention is shown; Figure 4 A cross-sectional view of a heat dissipation fan ring provided by an embodiment of the present invention is shown; Figure 5 A partial enlarged view of position C of the cross-sectional view provided by an embodiment of the present invention is shown; Figure 6 The simulation diagram of the heat dissipation fan provided by the embodiment of the present invention is shown. Figure 1 ; Figure 7 The simulation diagram of the heat dissipation fan provided by the embodiment of the present invention is shown. Figure 2 ; Figure 8 The simulation diagram of the heat dissipation fan provided by the embodiment of the present invention is shown. Figure 3 ; Fig. 9 The simulation diagram of the heat dissipation fan provided by the embodiment of the present invention is shown. Figure 4 ; Fig.10 The simulation diagram of the heat dissipation fan provided by the embodiment of the present invention is shown. Figure 5 .

[0026] Description of reference numerals: 100, inner ring; 110, first baffle ring; 111, air inlet; 112, air outlet; 113, partition; 120, second baffle ring; 121, extension portion; 122, bending portion; 200, outer ring; 210, outer wall; 220, third baffle ring; 230, sealing groove; 300, heating plate; 400, air outlet channel; A, first angle; B, second angle. DETAILED DESCRIPTION

[0027] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative work are within the scope of protection of the present invention. It should be noted that relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements. It should be noted that, in the absence of conflict, the features in the embodiments of the present invention may be combined with each other.

[0028] See attached Figure 1 To Attachment Figure 5 As shown, the present invention provides a rapid heat dissipation air ring for a heating plate, wherein the rapid heat dissipation air ring of the heating plate 300 is sleeved on the outside of the heating plate 300, and the rapid heat dissipation air ring of the heating plate 300 comprises: The inner ring 100 includes a first baffle ring 110 and a second baffle ring 120. The first baffle ring 110 is provided with an air inlet 111 and an air outlet 112. The second baffle ring 120 is fixedly connected to the first baffle ring 110. The second baffle ring 120 is arranged between the air inlet 111 and the air outlet 112 to separate the first baffle ring 110 into an air inlet side and an air outlet side. The outer ring 200 is sleeved on the outside of the inner ring 100, and the outer ring 200 includes an outer wall 210 and a third baffle ring 220. The third baffle ring 220 is fixedly connected to the side of the outer wall 210 close to the heating plate 300. The third baffle ring 220 and the second baffle ring 120 cooperate with each other to form an air outlet channel 400, and the air outlet channel 400 is connected to the air inlet 111.

[0029] Specifically, the inner ring 100 includes a first retaining ring 110 and a second retaining ring 120 , and the first retaining ring 110 and the second retaining ring 120 are fixedly connected. Preferably, the first retaining ring 110 and the second retaining ring 120 are integrally formed to improve the structural stability of the inner ring 100 . Specifically, the first baffle ring 110 is circumferentially provided with an air inlet 111 and an air outlet 112, and the air inlet 111 and the air outlet 112 are arranged in plurality, the air inlet 111 is arranged in a direction away from the heating plate 300, and the air outlet 112 is arranged in a direction close to the heating plate 300, and the second baffle ring 120 is arranged between the air inlet 111 and the air outlet 112, separating the first baffle ring 110 into an air inlet side and an air outlet side, the air inlet side is the side away from the heating plate 300, and the air outlet side is the side close to the heating plate 300.

[0030] Specifically, the outer ring 200 is sleeved on the outside of the inner ring 100, and the outer ring 200 and the inner ring 100 are fixedly connected by a fixing part. The outer ring 200 includes an outer wall 210 and a third retaining ring 220. The third retaining ring 220 is fixed to one end of the outer ring 200, and the inner ring 100 is sleeved on the other end of the outer ring 200. The third retaining ring 220 and the second retaining ring 120 cooperate with each other to form an air outlet channel 400, and the air outlet channel 400 is connected to the air inlet 111.

[0031] Specifically, a plurality of fixing holes are provided on the first retaining ring 110 in a direction close to the heating plate 300 , and the first retaining ring 110 is fixedly connected to the heating plate 300 through a fixing member.

[0032] See attached Figure 6 To Attachment Figure 8 As shown, an outer ring 200 and an inner ring 100 that cooperate with each other are arranged on the outside of the heating plate 300, an air inlet 111 is arranged on the inner ring 100, and the outer ring 200 and the inner ring 100 form an air outlet channel 400. The airflow enters through the air inlet 111, and the airflow velocity decays after reaching the top of the cavity. The velocity is increased when passing through the air outlet channel 400, and a negative pressure is formed in the area near the air outlet channel 400 of the inner ring 100. Under the action of the heat dissipation air circle, the air above the heating plate 300 flows into the heat dissipation air circle along the plate surface, and the air flow rate of the upper and lower inlets and outlets of the entire heat dissipation air circle is much larger than the air flow rate of the bottom air inlet hole, thereby achieving the effect of efficiently cooling the upper and lower surfaces of the heating plate 300.

[0033] In an optional embodiment, the second retaining ring 120 includes an extension portion 121 and a bending portion 122 , wherein one end of the extension portion 121 is connected to the first retaining ring 110 , and the other end of the extension portion 121 is connected to the bending portion 122 , and the bending portion 122 extends toward the direction close to the outer wall 210 .

[0034] See attached Figure 4 and attached Figure 5As shown, specifically, the second baffle ring 120 includes an extension portion 121 and a bending portion 122, the extension portion 121 and the bending portion 122 are integrally formed, the extension portion 121 extends in a direction close to the heating plate 300, and the bending portion 122 extends toward the air intake side, and the extension portion 121, the bending portion 122 and the third baffle ring 220 together constitute an air outlet channel 400.

[0035] Preferably, the length of the bending portion 122 is 3.5 mm, and the thickness of the bending portion 122 is 1.5 mm.

[0036] Preferably, the thickness of the extension portion 121 is 1.5 mm.

[0037] See attached Figure 4 As shown, in an optional embodiment, the extension portion 121 extends in a direction away from the outer wall 210 , and on a radial section of the rapid heat dissipation air ring, the extension portion 121 forms an angle of 70°-80° between the first baffle ring 110 on the air outlet side.

[0038] Specifically, on the radial section of the rapid heat dissipation air ring, the extension portion 121 forms a first angle A between the air outlet side and the first baffle ring 110, and the range of the first angle A is 70°-80°. Preferably, on the radial section of the rapid heat dissipation air ring, the first angle A formed between the extension portion 121 and the first baffle ring 110 on the air outlet side is 80°, and the extension portion 121 extends toward the air outlet side, which is conducive to forming a narrow air outlet channel 400 with the third baffle ring 220, which is conducive to accelerating the outflow of the air outlet channel 400, forming a greater negative pressure on the outer surface of the inner ring 100, and sucking in more gas.

[0039] See attached Figure 4 and attached Figure 5 As shown, in an optional embodiment, on the radial section of the rapid heat dissipation air ring, the bent portion 122 forms an angle of 115°-125° between the air inlet side and the extension portion 121 .

[0040] Specifically, on the radial section of the rapid heat dissipation air ring, the bend 122 forms a second angle B between the air inlet side and the extension 121, and the range of the second angle B is 115°-125°. Preferably, on the radial section of the rapid heat dissipation air ring, the second angle B formed between the bend 122 on the air inlet side and the extension 121 is 125°, and the bend 122 extends toward the air inlet side, which is conducive to the second baffle ring 120 and the third baffle ring 220 forming an air outlet channel 400, and the air outlet channel 400 narrows from the air inlet side to the air outlet side, which is conducive to the increase of the flow rate of the gas when passing through the air outlet channel 400, and the bend 122 and the inner wall of the outer wall 210 form the air outlet channel 400, which can guide the gas to flow out smoothly and concentratedly.

[0041] See attached Figure 3 As shown, in an optional embodiment, the diameter of the air inlet 111 on the first baffle ring 110 is smaller than the diameter of the air outlet 112 .

[0042] Specifically, the diameter of the air inlet 111 is smaller than the diameter of the air outlet 112, so that the air volume in and out of the upper and lower surfaces of the heating plate 300 is much larger than the air volume of the air inlet 111, thereby increasing the gas flow near the upper and lower surfaces of the heating plate 300 and accelerating the cooling rate.

[0043] See attached Figure 4 As shown, in an optional embodiment, the width of the air outlet channel 400 formed between the second blocking ring 120 and the third blocking ring 220 is in the range of 1.10 mm to 1.30 mm.

[0044] Preferably, the width of the air outlet channel 400 formed between the second baffle ring 120 and the third baffle ring 220 is set to 1.20 mm, so that the airflow is compressed when passing through the narrow area, thereby obtaining a higher outlet velocity.

[0045] See attached Figure 4 As shown, in an optional embodiment, the ratio of the height of the third retaining ring 220 to the height of the outer wall 210 is 2-2.1.

[0046] Preferably, the height of the third baffle ring 220 is set to 10 mm, the height of the outer wall 210 is set to 20.5 mm, and the ratio of the height of the third baffle ring 220 to the outer wall 210 is 2.05. If the height of the outer wall 210 is too high, the thickness of the top of the outer ring 200 is too small, so that the structural strength of the third baffle ring 220 is insufficient. If the height of the outer wall 210 is too low, the height of the second baffle ring 120 will also be reduced, resulting in insufficient airflow on the outer wall 210 of the second baffle ring 120, which affects the heat dissipation effect.

[0047] See attached Figure 3 As shown, in an optional embodiment, the air inlet 111 is provided in plurality, and the first baffle ring 110 is provided with a partition 113 on the air inlet side, and the partition 113 is used to separate the plurality of air inlets 111 .

[0048] Specifically, the number of air inlets can be 12 and arranged along the circumference of the inner ring.

[0049] For details, see the attached Fig. 9 and attached Fig.10As shown, according to the simulation results, when there is no partition 113 between the multiple air inlets 111, the airflow in the area interferes with each other, causing inconsistent airflow directions. The airflow flowing through the air outlet channel 400 does not flow out along the outer wall 210 of the inner ring 100, resulting in the inability to inhale the airflow on the upper and lower surfaces of the heating plate 300. Therefore, by providing a partition 113 between the air inlets 111 of the first baffle ring 110, mutual interference between the air inlets 111 can be avoided, and each air inlet 111 forms an independent air inlet cavity, which is conducive to a more stable and uniform inflow of airflow.

[0050] See attached Figure 4 As shown, in an optional embodiment, an air inlet channel is formed between the third baffle ring 220 and the heating plate 300 , and the air inlet channel is connected to the air outlet 112 .

[0051] The provision of the air inlet channel is beneficial to the inflow and outflow of gas on the upper and lower surfaces of the heating plate 300, improves the gas flow near the upper and lower surfaces of the heating plate 300, and accelerates the heat dissipation efficiency.

[0052] See attached Figure 2 As shown, a sealing groove 230 is provided between the outer wall 210 and the third retaining ring 220 , and the sealing groove 230 is used to fix the sealing ring to play a sealing role.

[0053] The above description is intended to be illustrative rather than restrictive, and those skilled in the art may make changes, modifications, substitutions and variations to the above embodiments within the scope of the present disclosure. Moreover, the above examples (or one or more of them) may be used in combination with each other, and it is contemplated that these embodiments may be combined with each other in various combinations or permutations.

Claims

1. A rapid heat dissipation air ring for a heating plate, the rapid heat dissipation air ring being sleeved on the outside of the heating plate (300), characterized in that: The rapid heat dissipation air ring comprises: An inner ring (100), the inner ring (100) comprising a first baffle ring (110) and a second baffle ring (120), the first baffle ring (110) being provided with an air inlet (111) and an air outlet (112), the second baffle ring (120) being fixedly connected to the first baffle ring (110), the second baffle ring (120) being arranged between the air inlet (111) and the air outlet (112), and dividing the first baffle ring (110) into an air inlet side and an air outlet side; An outer ring (200), wherein the outer ring (200) is sleeved outside the inner ring (100), the outer ring (200) comprises an outer wall (210) and a third baffle ring (220), the third baffle ring (220) is fixedly connected to a side of the outer wall (210) close to the heating plate (300), the third baffle ring (220) and the second baffle ring (120) cooperate with each other to form an air outlet channel (400), and the air outlet channel (400) is connected to the air inlet (111).

2. The rapid heat dissipation fan for a heating plate according to claim 1, characterized in that: The second retaining ring (120) comprises an extension portion (121) and a bent portion (122), one end of the extension portion (121) being connected to the first retaining ring (110), the other end of the extension portion (121) being connected to the bent portion (122), and the bent portion (122) extending in a direction close to the outer wall (210).

3. The rapid heat dissipation fan for a heating plate according to claim 2, characterized in that: The extension portion (121) extends in a direction away from the outer wall (210), and on a radial cross section of the rapid heat dissipation air ring, the extension portion (121) forms an angle of 70°-80° between the extension portion (121) and the first baffle ring (110) on the air outlet side.

4. The rapid heat dissipation fan for a heating plate according to claim 2, characterized in that: On the radial cross-section of the rapid heat dissipation air ring, the bent portion (122) forms an angle of 115°-125° between the air inlet side and the extension portion (121).

5. The rapid heat dissipation fan for a heating plate according to claim 1, characterized in that: The diameter of the air inlet (111) on the first baffle ring (110) is smaller than the diameter of the air outlet (112).

6. The rapid heat dissipation fan for a heating plate according to claim 1, characterized in that: The air outlet channel (400) formed between the second blocking ring (120) and the third blocking ring (220) has a width ranging from 1.10 mm to 1.30 mm.

7. The rapid heat dissipation fan for a heating plate according to claim 1, characterized in that: The ratio of the height of the third retaining ring (220) to the height of the outer wall (210) is 2-2.

1.

8. The rapid heat dissipation fan for a heating plate according to any one of claims 1 to 7, characterized in that: The air inlets (111) are arranged in plurality, and the first baffle ring (110) is provided with a partition plate (113) on the air inlet side, the partition plate (113) being used to separate the plurality of air inlets (111).

9. The rapid heat dissipation fan for a heating plate according to claim 1, characterized in that: An air inlet channel is formed between the third baffle ring (220) and the heating plate (300), and the air inlet channel is in communication with the air outlet (112).

10. The rapid heat dissipation fan for a heating plate according to claim 1, characterized in that: A sealing groove (230) is provided between the outer wall (210) and the third retaining ring (220).

Images