Protective device for observation window

Abstract

The utility model discloses a protective device for an observation window, which relates to the technical field of thermal protection and comprises an upper panel and a lower supporting plate which are stacked up and down and fixedly connected through fixing bolts, openings are formed in the middle of the upper panel and the middle of the lower supporting plate in a penetrating manner, glass sheets are arranged in the openings, and brackets are arranged outside the glass sheets. An opening is formed in the upper portion of the bracket, the bracket supports a glass sheet and cools the glass sheet, a pressing plate frame is arranged above the bracket and presses the glass sheet, and the pressing plate frame is located in the opening. According to the utility model, gas with lower temperature is conveyed to the surface of the glass sheet through a gap on one side of the surface of the glass sheet needing thermal protection, a gas film is formed along the direction of high-temperature airflow, and the gas film isolates the surface of the glass sheet from the high-temperature airflow, so that the heat insulation effect is achieved, and meanwhile, particulate matters are not attached to the glass sheet of the observation window, so that the cleanliness of the glass is ensured.

Description

Technical Field

[0001] This utility model relates to the field of thermal protection technology, specifically a protective device for observation windows. Background Technology

[0002] Thermal protection is primarily used to protect product structural components from ablation in high-temperature environments. Currently, the main measures for thermal protection include thermal insulation materials and heat-resistant structures. Protective devices used for observation windows fall under the category of heat-resistant structural measures.

[0003] Heat protection structures mainly include heat absorption (heat sink) heat protection, radiation heat protection, ablation heat protection, surface insulation heat protection, and heat pipes. However, these structures do not meet the protection requirements for the observation window and are also relatively complex.

[0004] Film cooling has attracted widespread attention due to its advantages such as simple structure, reusability, and good cooling performance, and is considered one of the most promising active thermal protection technologies for the future. Therefore, this solution provides a protective device for an observation window, which uses film cooling in the throat of a Laval nozzle for thermal protection. Utility Model Content

[0005] The purpose of this invention is to provide a protective device for observation windows to address the shortcomings of existing technologies.

[0006] A protective device for an observation window includes an upper panel and a lower support plate stacked on top of each other and fixedly connected by fixing bolts. An opening is opened through the middle of both the upper panel and the lower support plate. A glass plate is placed inside the opening. A bracket is placed outside the glass plate. The bracket supports the glass plate and cools the glass plate. A pressure plate frame is placed above the bracket to press down the glass plate. The pressure plate frame is located inside the opening.

[0007] The bracket has a narrow slit along the lower plane of the glass sheet, from which cooling air is blown out to form an air film along the lower surface of the glass sheet to cool it. An air inlet pipe is installed above the bracket, and the air inlet pipe passes through the lower support plate and the upper panel in sequence from below and extends to the outside.

[0008] Furthermore, the bracket includes a cooling plate, a support plate, and an L-shaped bracket plate. The cooling plate and the three support plates surround the glass sheet to form a square frame structure to protect the glass sheet from all sides. The L-shaped bracket plate is located below the square frame structure to support the glass sheet.

[0009] Furthermore, the L-shaped bracket plate consists of a horizontal strip and two L-shaped strips. The two L-shaped strips are respectively connected to the two ends of the horizontal strip to form a U-shaped structure. The short plates of the two L-shaped strips are respectively fixed to the two end sides of the cooling plate. The long plates of the L-shaped strips and the horizontal strip support three support plates. The top width of the support plates is smaller than the surface width of the long plates of the L-shaped strips and the horizontal strips.

[0010] Furthermore, the cooling plate includes an L-shaped plate, an air collection chamber, an air duct, an air inlet, a support side plate, and a guide strip. The air collection chamber is formed through the bottom of the L-shaped plate. An air duct is formed at the bottom of the L-shaped plate on one side of the air collection chamber. The air duct is connected to the air collection chamber. A support side plate for supporting the glass sheet is formed at the bottom of the L-shaped plate above the air duct. An air inlet is formed at the position of the L-shaped plate corresponding to the position of the air inlet pipe. One end of the air inlet is connected to the air collection chamber, and the other end of the air inlet is connected to the air inlet pipe.

[0011] Furthermore, the top wall of the supporting side plate and the bottom wall of the glass sheet end are attached together, the air duct faces the lower surface of the corresponding end of the glass sheet, and the cooling air ejected from the air duct forms an air film on the lower surface of the glass sheet to cool the glass sheet.

[0012] Furthermore, the upper and lower surfaces of the glass sheet are sealed to the pressure plate frame and the bracket respectively by a first sealing strip and a second sealing strip. Four first sealing strips are installed at the position where the upper surface of the glass sheet contacts the bottom of the pressure plate frame, and the four first sealing strips form a rectangle. Four second sealing strips are installed at the position where the lower surface of the glass sheet contacts the bottom of the bracket, and the four second sealing strips form a rectangle.

[0013] Furthermore, the four second sealing strips are respectively attached to the supporting side plate, the long plate portion of the two L-shaped strips, and the upper surface of the horizontal strip.

[0014] Furthermore, both the first sealing strip and the second sealing strip are made of silicone rubber, with the first sealing strip having a thickness of 2-3 mm and the second sealing strip having a thickness of 2-3 mm.

[0015] Furthermore, the width of the airway opening near the air collection chamber gradually decreases from far to near, the bottom surface of the air collection chamber is inclined, and the width of the air collection chamber opening near the airway opening gradually decreases from far to near and connects with the opening of the air collection chamber at the narrowest gap.

[0016] Furthermore, the inner cavity of the air collecting chamber protrudes and extends away from the supporting side plate to form a guide strip. The upper surface of the guide strip is inclined to facilitate the guidance of the cooling air flowing into the air inlet and to guide the cooling air to one side of the air collecting chamber.

[0017] The advantages of this utility model compared with the prior art are as follows:

[0018] 1. This solution uses a bracket. By opening a gas collection chamber and gas duct in the bracket, cooling gas is blown towards the bottom of the glass plate, forming a gas film on the lower surface of the glass plate, thereby insulating and cooling the glass plate. At the same time, it can isolate solid carbon particles in the gas and prevent carbon particles from adhering to the surface of the observation window.

[0019] 2. This solution seals the glass sheet around its perimeter by setting a first sealing strip and a second sealing strip on the upper and lower surfaces of the glass sheet, respectively, to prevent high-temperature airflow from escaping through the gaps in the glass sheet.

[0020] 3. This solution adopts the Laval nozzle throat air film cooling method, which delivers low-temperature gas to the surface of the glass sheet that needs heat protection through the gap on one side of the glass sheet. The gas film forms along the direction of the high-temperature airflow, which isolates the glass sheet surface from the high-temperature airflow, thereby achieving the heat insulation effect. At the same time, the observation window glass sheet is not subject to the adhesion of particles, ensuring the cleanliness of the glass. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the protective device for the observation window proposed in this scheme from a first-view perspective.

[0022] Figure 2 This is a schematic diagram of the protective device for the observation window proposed in this scheme from a second-view perspective.

[0023] Figure 3 This is a schematic diagram of the protective device for the observation window proposed in this scheme from a first-view perspective.

[0024] Figure 4 This is a schematic diagram of the structure on the bracket proposed in this scheme;

[0025] Figure 5 This is a structural schematic diagram of the L-shaped bracket plate proposed in this solution;

[0026] Figure 6 This is a schematic diagram of the cooling plate proposed in this solution;

[0027] Figure 7 For this plan Figure 1 Sectional view at point AA;

[0028] Figure 8 For this plan Figure 7Enlarged view of the structure at point B in the middle.

[0029] Reference numerals: 1. Top panel; 2. Lower support plate; 3. Glass plate; 4. Pressure plate frame; 5. Bracket; 6. Air inlet pipe; 7. First sealing strip; 8. Second sealing strip; 9. Fixing bolt;

[0030] 51. Cooling plate; 52. Support plate; 53. L-shaped bracket plate;

[0031] 511. L-shaped plate; 512. Air collection chamber; 513. Air inlet; 514. Air inlet; 515. Supporting side plate; 516. Guide strip;

[0032] 531. L-shaped slats; 532. Horizontal slats. Detailed Implementation

[0033] This embodiment provides a protective device for the observation window, as shown in the instruction manual. Figure 1-8 As shown, it includes an upper panel 1 and a lower support plate 2 stacked on top of each other and fixedly connected by fixing bolts 9. The upper panel 1 and the lower support plate 2 are installed on the outside of a circular structure that generates heat. Since there is gas flow on the downward-facing surface of the observation window glass, the glass plate 3 in the observation window structure is designed with thermal protection. An opening is opened through the middle of both the upper panel 1 and the lower support plate 2. The glass plate 3 is placed inside the opening, thus forming an observation window structure installed outside the gas passage, which facilitates observation of the structure inside the gas passage. A bracket 5 is set on the outside of the glass plate 3. The bracket 5 supports the glass plate 3 and cools the glass plate 3. A pressure plate frame 4 is set above the bracket 5 to press down the glass plate 3. The pressure plate frame 4 is located inside the opening, thus fixing the glass plate 3 between the pressure plate frame 4 and the bracket 5. This facilitates observation and also cools the bracket 5, preventing the glass from deforming or even cracking due to high temperature.

[0034] The bracket 5 has a narrow slit along the lower plane of the glass plate 3. Cooling air is blown out from the slit and forms an air film along the lower surface of the glass plate 3 to cool the glass plate 3. An air inlet pipe 6 is installed above the bracket 5. The air inlet pipe 6 passes through the lower support plate 2 and the upper panel 1 from below and extends to the outside. After the cooling air enters the interior of the bracket 5 through the air inlet pipe 6, it is blown out from the slit. Since the slit faces the glass plate 3, the blown cooling air will blow over the lower surface of the glass plate 3, thereby forming an air film. This serves two purposes: first, to cool the glass surface, and second, to isolate solid carbon particles in the combustion gas and prevent carbon particles from adhering to the surface of the observation window.

[0035] Please refer to the instruction manual attached. Figure 4-6The bracket 5 in this embodiment will be described in detail. The bracket 5 includes a cooling plate 51, a support plate 52, and an L-shaped bracket plate 53. The cooling plate 51 and the three support plates 52 surround the glass sheet 3 to form a square frame structure to protect the glass sheet 3 from all sides. The L-shaped bracket plate 53 is located below the square frame structure to support the glass sheet 3, thereby fixing the glass sheet 3 above the bracket 5. While fixing the glass sheet 3, the bracket 5 can also protect and seal the glass sheet 3 from all sides. At the same time, the cooling air blown out of the bracket 5 can cool the glass sheet 3.

[0036] Please refer to the instruction manual attached. Figure 5 The L-shaped bracket plate 53 in this embodiment is described in detail. The L-shaped bracket plate 53 consists of a horizontal strip 532 and two L-shaped strips 531. The two L-shaped strips 531 are respectively connected to both ends of the horizontal strip 532, forming a U-shaped structure. The shorter portions of the two L-shaped strips 531 are fixed to the two ends of the cooling plate 51. The longer portions of the L-shaped strips 531 and the horizontal strip 532 support three supporting pressure plates 52. The top width of each supporting pressure plate 52 is smaller than that of the L-shaped strip 532. The surface width of the long plate section 31 and the horizontal strip 532 is such that when the support plate 52 is above the L-shaped strip 531 and the horizontal strip 532, there is still extra space on the upper surface of the L-shaped strip 531 and the horizontal strip 532, which can be used to assemble the glass sheet 3. During assembly, the support plate 52 is located above the outer side of the long strip of the L-shaped strip 531, and the inner side is used to support the end edge of the glass sheet 3, thereby assembling the glass sheet 3 above the bracket 5 and using the bracket 5 to support the glass sheet 3.

[0037] Please refer to the instruction manual attached. Figure 6 The cooling plate 51 in this embodiment is described in detail below. The cooling plate 51 includes an L-shaped plate 511, a gas collecting cavity 512, an air duct 513, an air inlet 514, a supporting side plate 515, and a guide strip 516. The bottom of the L-shaped plate 511 has a through-hole opening for the gas collecting cavity 512. The air duct 513 is located on one side of the bottom of the L-shaped plate 511, and the air duct 513 is connected to the gas collecting cavity 512. The supporting side plate 515 for supporting the glass sheet 3 is formed at the bottom of the L-shaped plate 511 above the air duct 513. An air inlet 514 is provided at the position of the air inlet pipe 6 on the plate 511. One end of the air inlet 514 is connected to the air collection chamber 512, and the other end of the air inlet 514 is connected to the air inlet pipe 6. Cooling gas enters the air inlet 514 through the air inlet pipe 6 and further enters the air collection chamber 512. After the cooling gas is evenly distributed throughout the air collection chamber 512, it flows out from the gap of the air collection chamber 512 toward the air passage 513 and is further blown onto the lower surface of the glass plate 3 through the air passage 513, thereby forming an air film, which cools down the gas and isolates solid carbon particles in the combustion gas.

[0038] Please refer to the instruction manual attached. Figure 7-8 The cooling process of the cooling plate 51 for cooling the glass sheet 3 in this embodiment is further explained as follows: the top wall of the supporting side plate 515 is attached to the bottom wall of the end of the glass sheet 3, the air duct 513 faces the lower surface of the corresponding end of the glass sheet 3, and the cooling air ejected from the air duct 513 forms an air film on the lower surface of the glass sheet 3 to cool the glass sheet 3. Furthermore, the width of the opening of the air duct 513 near the air collection chamber 512 gradually decreases from far to near. Please refer to the appendix of the instruction manual. Figure 8 The gap between the air inlet 513 and the air collecting chamber 512 is 0.1mm-0.8mm, with 0.5mm being optimal. The expansion angle at the gap, i.e. the throat, is 10°-20°, with 15° being optimal. This allows the cooling gas to enter the throat relatively evenly and form an air film. Then, the throat gradually expands outward to match the flow rate of the cooling gas delivered from the air collecting chamber 512, forming an air film that covers the throat wall well, thereby achieving effective cooling and meeting the equipment's requirements for high-speed airflow.

[0039] Continue to refer to the instruction manual appendix Figure 8 The bottom surface of the air collecting chamber 512 is inclined, and the width of the opening of the air collecting chamber 512 near the air passage 513 gradually decreases from far to near and connects with the opening of the air collecting chamber 512 at the narrowest gap.

[0040] Therefore, when the intake pipe 6 continuously supplies cooling air to the intake port 514, the cooling air enters the gas collecting chamber 512 through the intake port 514. Due to the small gap at the connection between the gas collecting chamber 512 and the air passage 513, the gas is evenly distributed in the gas collecting chamber 512 under the action of the gas pressure in the gas collecting chamber 512, and then blown towards the air passage 513 through the gap. As the air passage 513 is shaped like a trumpet, it is sprayed towards the lower surface of the glass plate 3 in a heat dissipation manner. The cooling air continuously enters the gas collecting chamber 512 from the intake pipe 6, so that the gas is continuously blown towards the bottom of the glass plate 3. Therefore, an air film is formed under the glass plate 3, which can cool the gas and isolate solid carbon particles in the combustion gas at the same time.

[0041] Continue to refer to the instruction manual appendix Figure 8To further explain the process of cooling gas entering the gas collecting cavity 512 in this embodiment, a guide strip 516 is formed by protruding from the inner cavity of the gas collecting cavity 512 near the supporting side plate 515 and extending away from the supporting side plate 515. The upper surface of the guide strip 516 is inclined to facilitate the guidance of the cooling gas flowing into the air inlet 514 and to guide the cooling gas to one side of the gas collecting cavity 512. Therefore, when the cooling gas enters the gas collecting cavity 512 from the air inlet 514, the guide strip 516 blocks the upper part of the gap. Therefore, when the gas is shot into the gas collecting cavity 512, it will not flow out directly from the gap, but will flow away from the gap under the guidance of the guide strip 516, thus producing the effect of "gas collecting". This makes the gas evenly distributed in the gas collecting cavity 512. After the gas collecting cavity 512 is filled with gas, the gas flows out from the gap to the air passage 513 and is further blown towards the lower part of the glass plate 3 to form an air film.

[0042] Please refer to the instruction manual attached. Figure 3 , 7 8. Further explanation of the glass sheet 3 in this embodiment: The upper and lower surfaces of the glass sheet 3 are sealed to the pressure plate frame 4 and the bracket 5 respectively by the first sealing strip 7 and the second sealing strip 8. Both the first sealing strip 7 and the second sealing strip 8 are made of silicone rubber. Considering the characteristics of silicone rubber, the thickness of the first sealing strip 7 is 2-3 mm, and the thickness of the second sealing strip 8 is 2-3 mm. In this embodiment, a 3 mm thick first sealing strip 7 and second sealing strip 8 are used because our experiments have shown that although a sealing effect can be achieved when the thickness of the sealing strip is greater than 3 mm, The glass sheet 3 is subjected to a strong load. After long-term use, the contact area between the glass sheet 3 and the sealing strip is prone to deformation under stress. In severe cases, cracks may appear directly. When the thickness of the sealing strip is less than 2mm, although the load on the glass sheet 3 is small, gaps may appear at the contact points between the glass sheet 3 and the pressure plate frame 4 and bracket 5, resulting in poor sealing. Therefore, a thickness of 2-3mm is better. Among them, when using a sealing strip with a thickness of 3mm, the sealing strip in the compressed state has both compression to achieve a sealing effect and will not be overloaded, thus avoiding damage to the glass, resulting in the best effect.

[0043] Four first sealing strips 7 are installed at the contact point between the upper surface of the glass plate 3 and the bottom of the pressure plate frame 4, forming a rectangular structure. Four second sealing strips 8 are installed at the contact point between the lower surface of the glass plate 3 and the bottom of the bracket 5, also forming a rectangular structure. The four second sealing strips 8 are respectively attached to the upper surfaces of the supporting side plate 515, the long sections of the two L-shaped strips 531, and the horizontal strip 532. Please refer to the above description and the accompanying instruction manual. Figure 3As shown, the four second sealing strips 8 form a rectangular structure above the bottom of the bracket 5, with one second sealing strip 8 located above the supporting side plate 515, another second sealing strip 8 located above the horizontal strip 532, and the remaining two second sealing strips 8 located above the long plate of the L-shaped strip 531.

[0044] The upper and lower surfaces of the glass slide 3 are sealed around the perimeter using the first sealing strip 7 and the second sealing strip 8 to prevent high-temperature airflow from the pipe from entering the other side of the observation window, i.e., the instrument cavity (not shown in the instrument cavity diagram, and not the focus of this application, but for illustrative purposes only). At the same time, the first sealing strip 7 and the second sealing strip 8, made of silicone rubber of a certain thickness, are used as a heat protection measure to prevent high-temperature airflow from the observation window from entering the instrument chamber.

[0045] In the description of this utility model, it should be understood that the terms "center," "longitudinal," "transverse," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential," etc., indicating the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, features defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, unless otherwise stated, "a plurality of" means two or more.

[0046] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0047] In the description of this utility model, the terms "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this utility model. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0048] Although embodiments of the present invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A protective device for an observation window, characterized in that, It includes an upper panel (1) and a lower support plate (2) stacked on top of each other and fixedly connected by fixing bolts (9). Both the upper panel (1) and the lower support plate (2) have openings through the middle. A glass sheet (3) is placed inside the opening. A bracket (5) is placed outside the glass sheet (3). The bracket (5) supports the glass sheet (3) and cools the glass sheet (3). A pressure plate frame (4) is placed above the bracket (5) to press down the glass sheet (3). The pressure plate frame (4) is located inside the opening. The bracket (5) has a narrow slit along the lower plane of the glass sheet (3). Cooling air is blown out from the slit and forms an air film along the lower surface of the glass sheet (3) to cool the glass sheet (3). An air inlet pipe (6) is installed above the bracket (5). The air inlet pipe (6) passes through the lower support plate (2) and the upper panel (1) from below and extends to the outside.

2. The protective device for an observation window according to claim 1, characterized in that: The bracket (5) includes a cooling plate (51), a support plate (52), and an L-shaped bracket plate (53). The cooling plate (51) and the three support plates (52) surround the glass sheet (3) to form a square frame structure to protect the glass sheet (3) from all sides. The L-shaped bracket plate (53) is located below the square frame structure to support the glass sheet (3).

3. The protective device for an observation window according to claim 2, characterized in that: The L-shaped bracket plate (53) consists of a horizontal strip (532) and two L-shaped strips (531). The two L-shaped strips (531) are respectively connected to the two ends of the horizontal strip (532) to form a U-shaped structure. The short plates of the two L-shaped strips (531) are respectively fixed to the two ends of the cooling plate (51). The long plates of the L-shaped strips (531) and the horizontal strips (532) support three support plates (52). The top width of the support plates (52) is smaller than the surface width of the long plates of the L-shaped strips (531) and the horizontal strips (532).

4. The protective device for an observation window according to claim 3, characterized in that: The cooling plate (51) includes an L-shaped plate (511), a gas collecting chamber (512), an air duct (513), an air inlet (514), a supporting side plate (515), and a guide strip (516). The bottom of the L-shaped plate (511) has a through-hole for the gas collecting chamber (512). The bottom of the L-shaped plate (511) has an air duct (513) located on one side of the gas collecting chamber (512). The air duct (513) and the gas collecting chamber... The cavity (512) is connected, and the bottom of the L-shaped plate (511) is located above the airway (513) to form a supporting side plate (515) for supporting the glass plate (3). The L-shaped plate (511) has an air inlet (514) at the position corresponding to the air inlet pipe (6). One end of the air inlet (514) is connected to the air collection cavity (512), and the other end of the air inlet (514) is connected to the air inlet pipe (6).

5. The protective device for an observation window according to claim 4, characterized in that: The top wall of the supporting side plate (515) and the bottom wall of the end of the glass sheet (3) are attached together. The air duct (513) faces the lower surface of the corresponding end of the glass sheet (3). The cooling gas ejected from the air duct (513) forms an air film on the lower surface of the glass sheet (3) to cool the glass sheet (3).

6. The protective device for an observation window according to claim 5, characterized in that: The upper and lower surfaces of the glass sheet (3) are sealed to the pressure plate frame (4) and the bracket (5) respectively by the first sealing strip (7) and the second sealing strip (8). Four first sealing strips (7) are installed at the position where the upper surface of the glass sheet (3) contacts the bottom of the pressure plate frame (4), and the four first sealing strips (7) form a rectangle. Four second sealing strips (8) are installed at the position where the lower surface of the glass sheet (3) contacts the bottom of the bracket (5), and the four second sealing strips (8) form a rectangle.

7. The protective device for an observation window according to claim 6, characterized in that: The four second sealing strips (8) are respectively attached to the upper surface of the supporting side plate (515), the long plate portion of the two L-shaped strips (531), and the horizontal strip (532).

8. The protective device for an observation window according to any one of claims 6-7, characterized in that: Both the first sealing strip (7) and the second sealing strip (8) are made of silicone rubber. The thickness of the first sealing strip (7) is 2-3 mm, and the thickness of the second sealing strip (8) is 2-3 mm.

9. The protective device for an observation window according to claim 5, characterized in that: The width of the airway opening (513) near the air collection chamber (512) gradually decreases from far to near. The bottom surface of the air collection chamber (512) is inclined. The width of the opening of the air collection chamber (512) near the airway opening (513) gradually decreases from far to near and connects with the opening of the air collection chamber (512) at the narrowest gap.

10. The protective device for an observation window according to claim 9, characterized in that: The inner cavity of the gas collecting chamber (512) extends outward from the side away from the supporting side plate (515) to form a guide strip (516). The upper surface of the guide strip (516) is inclined to facilitate the guidance of the cooling air flowing into the air inlet (514) and to guide the cooling air to one side of the gas collecting chamber (512).

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