A method and system for direct molding of optical lenses based on fluid forming

Abstract

The present invention provides a method and system for direct molding of optical lenses based on fluid molding. The molding method is as follows: first, a container, a fluid molding mold, a density matching liquid, and an optical polymer liquid are prepared; then, the fluid molding mold is fixed in the center of the container, and the optical polymer liquid is injected into the fluid molding mold. The fluid molding mold filled with the optical polymer liquid divides the inner cavity of the container into an upper and a lower sealed cavity; then, the density matching liquid is injected into the upper and lower sealed cavities so that the fluid molding mold is completely immersed in the density matching liquid. The optical lens is formed and solidified in the fluid molding mold. The molding system includes a container and a fluid molding mold. The present invention solves the problem that the complexity of the manufacturing process and the required professional equipment hinder the rapid molding of optical lenses. The rapid molding of optical lenses can be achieved without grinding and surface polishing, and the mirror surface shape of the optical lens can be adjusted in real time.

Description

Technical Field

[0001] The present invention relates to the technical field of fluid forming, and in particular to a method and system for directly forming an optical lens based on fluid forming. Background Art

[0002] Lenses are fundamental components of any optical system, from microscopes to telescopes, holograms, glasses, data storage devices, lasers, and more. The manufacture of lenses or lens molds relies on mechanical processes such as grinding and machining, followed by polishing of the optical surfaces. The demand for high-quality surfaces requires specialized and expensive equipment, and the fabrication of non-standard optical surfaces remains challenging. The complexity of these manufacturing processes and the specialized equipment required have hindered the rapid prototyping of optical components.

[0003] It is natural that three-dimensional (3-D) printing technology is considered as a potential platform for optical lens fabrication, but so far the quality of the printed parts is not sufficient for optical applications and requires complex post-processing.

[0004] In order to solve the problem of rapidly manufacturing various optical lenses with high surface quality, it is necessary to propose a lens system that can produce high surface quality by utilizing the smooth liquid-liquid interface of polymer liquid and density matching liquid. Summary of the Invention

[0005] In response to the technical problems existing in the above-mentioned background technology, the present invention proposes a direct forming method and system for optical lenses based on fluid forming. The concept is reasonable and ingenious, and solves the problem that the complexity of the manufacturing process and the required professional equipment hinder the rapid forming of optical lenses. The lens can be quickly formed without grinding and surface polishing. The mirror surface shape presented by the optical liquid can be changed by the size of the fluid forming mold, the volume of the optical polymer liquid and the pressure of the density matching liquid in the upper and lower sealed cavities.

[0006] To solve the above technical problems, the present invention provides a direct forming method for an optical lens based on fluid forming, which first prepares a container, a fluid forming mold, a density matching liquid and an optical polymer liquid; then fixes the fluid forming mold in the center of the container, and then injects the optical polymer liquid into the fluid forming mold. At this time, the fluid forming mold filled with the optical polymer liquid divides the inner cavity of the container into an upper sealed cavity and a lower sealed cavity; then, the density matching liquid is injected into the upper sealed cavity and the lower sealed cavity so that the fluid forming mold is completely immersed in the density matching liquid, and utilizes the smooth liquid-liquid interface between the optical polymer liquid and the density matching liquid to quickly form and solidify in the fluid forming mold to form an optical lens with high surface quality.

[0007] The method for directly molding an optical lens based on fluid forming, wherein: an upper density matching liquid is injected into the upper sealed cavity, and a lower density matching liquid is injected into the lower sealed cavity; the surface shape of the optical lens is formed by forming different pressure differences between the upper sealed cavity and the lower sealed cavity by respectively adjusting the amount of the upper density matching liquid injected into the upper sealed cavity and the density matching liquid injected into the lower sealed cavity, thereby controlling the upper and lower surface shapes of the optical lens.

[0008] In the method for directly forming an optical lens based on fluid forming, the density matching liquid has the same density as the optical polymer liquid, and no chemical reaction occurs between the density matching liquid and the optical polymer liquid.

[0009] The optical lens direct molding method based on fluid forming, wherein: the optical polymer liquid is injected into the fluid forming mold immersed in the density matching liquid to form a lens shape with a diameter of 50-100 mm.

[0010] The optical lens direct molding method based on fluid molding, wherein: the optical polymer liquid after molding is solidified by a solidification device; and the optical polymer liquid forms an optical lens with a refractive index of 1.5-1.8 after solidification.

[0011] The direct forming method of an optical lens based on fluid forming, wherein: the curing device adopts a water bath heating pot, and the container containing the fluid forming mold, the density matching liquid, and the optical polymer liquid is immersed in the water bath heating pot for heating to solidify the optical polymer liquid.

[0012] The optical lens direct molding method based on fluid molding, wherein: the optical polymer liquid after molding can also be cured by heating or UV curing; and when UV curing the optical polymer liquid, a UV curing lamp is used to uniformly irradiate the optical polymer liquid to solidify it;

[0013] The fluid forming-based direct forming method for an optical lens, wherein: the container is a closed can-shaped container, the upper end of which is provided with an upper pressure joint connected to the upper sealed cavity, and the lower end is provided with a lower pressure joint connected to the lower sealed cavity; at the same time, the side wall of the container is a sandwich structure, and the upper end side wall and the lower end side wall of the container are also respectively matched with an upper circulating water inlet and outlet joint and a lower circulating water inlet and outlet joint connected to the sandwich structure.

[0014] A fluid forming-based optical lens direct molding system comprises a container and a fluid forming mold; the container is a closed canned container, and its side wall is a sandwich structure; the upper and lower side walls of the container are respectively matched with an upper circulating water inlet and outlet joint and a lower circulating water inlet and outlet joint connected to the sandwich structure; the fluid forming mold is matched and installed in the center of the container; when the fluid forming mold is filled with an optical polymer liquid, it can divide the inner cavity of the container into an upper sealed cavity and a lower sealed cavity; the upper end of the container is provided with an upper layer pressurizing joint connected to the upper sealed cavity, and the lower end is provided with a lower layer pressurizing joint connected to the lower sealed cavity.

[0015] The optical lens direct molding system based on fluid forming, wherein: the container includes a fluid forming tank body, a tank body upper cover and a tank body lower cover; the top and bottom of the fluid forming tank body are both open, and the side wall is the sandwich structure; the upper circulating water inlet and outlet joint is matched and arranged on one side of the upper end of the fluid forming tank body; the lower circulating water inlet and outlet joint is matched and arranged on one side of the lower end of the fluid forming tank body; the lower layer pressurizing joint is matched and arranged on the other side of the lower end of the fluid forming tank body; the tank body upper cover and the tank body lower cover are respectively matched and installed at the openings at the top and bottom of the fluid forming tank body to close the fluid forming tank body.

[0016] The optical lens direct molding system based on fluid forming, wherein: the central area of ​​the upper cover of the tank body is matched with an upper perspective window installed; the central area of ​​the lower cover of the tank body is matched with a lower perspective window installed; the upper layer pressurized joint is matched with the upper cover of the tank body.

[0017] The optical lens direct molding system based on fluid molding, wherein: the molding system also includes a curing device; the curing device is used to solidify the optical polymer liquid injected into the fluid molding mold.

[0018] The optical lens direct molding system based on fluid forming, wherein: the curing device uses a water bath heating pot to cure the optical polymer liquid injected into the fluid forming mold.

[0019] By adopting the above technical solution, the present invention has the following beneficial effects:

[0020] The direct optical lens forming method based on fluid forming of the present invention is rationally and ingeniously conceived, and solves the problem that the complexity of the manufacturing process and the required specialized equipment hinder the rapid forming of optical lenses. The rapid forming and production of lenses can be achieved without the need for grinding and surface polishing. The mirror-like surface shape presented by the optical liquid can be changed by adjusting the size of the fluid forming mold, the volume of the optical polymer liquid, and the pressure of the density-matching liquid in the upper and lower sealed cavities. The optical polymer liquid shrinks and its density changes during the curing process. By adjusting the pressure of the upper and lower sealed cavities, it can be ensured that the shape of the polymer liquid after curing remains consistent with that before curing.

[0021] Compared to traditional lens injection molding, the manufacturing time required for this method is disproportionate to the volume produced, enabling rapid production of parts of any size. Furthermore, the molding method is compatible with a wide range of curable liquids with varying optical and mechanical properties. Importantly, this method requires no specialized equipment and naturally achieves nanoscale surface quality.

[0022] The optical lens direct molding system based on fluid forming of the present invention has a simple and reasonable structural design and can produce lenses without any mechanical processing. Its simplicity and affordability make it a natural candidate for the production of economical and affordable glasses. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0024] Figure 1 Schematic diagram of the direct forming method of an optical lens based on fluid forming according to the present invention;

[0025] Figure 2 Schematic diagram of the structure of the optical lens direct molding system based on fluid forming of the present invention;

[0026] Figure 3 It is a cross-sectional view of the optical lens direct molding system based on fluid molding of the present invention. DETAILED DESCRIPTION

[0027] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0028] The present invention will be further explained below with reference to specific embodiments.

[0029] like Figure 1 As shown, the present embodiment provides a method for direct molding of an optical lens based on fluid molding, which is implemented by utilizing a direct molding system of an optical lens based on fluid molding.

[0030] like Figure 1-3 As shown, the optical lens direct molding system based on fluid molding of the present invention includes a container 1, a fluid molding mold 2 and a curing device 3.

[0031] The container 1 is a closed canned container, which includes a fluid-formed can body 11, a can body upper cover 12 and a can body lower cover 13.

[0032] The top and bottom of the fluid forming tank body 11 are both open, and the side walls are a sandwich structure. One side of the upper end is matched with an upper circulating water inlet and outlet joint 111 protruding outward thereof, and one side of the lower end is matched with a lower circulating water inlet and outlet joint 112 protruding outward thereof; the upper circulating water inlet and outlet joint 111 is connected to the inner cavity of the side wall sandwich structure 110 at the upper end of the fluid forming tank body 11, and the lower circulating water inlet and outlet joint 112 is connected to the inner cavity of the side wall sandwich structure 110 at the lower end of the fluid forming tank body 11; at the same time, one side of the lower end of the fluid forming tank body 11 is also provided with a lower layer pressurizing joint 113 protruding outward thereof; the lower layer pressurizing joint 113 is connected to the inner cavity of the fluid forming tank body 11.

[0033] The tank upper cover 12 and the tank lower cover 13 are respectively matched and installed at the openings at the top and bottom of the fluid forming tank body 11 to close the fluid forming tank body 11; the central area of ​​the tank upper cover 12 is matched and installed with an upper perspective window 121; the central area of ​​the tank lower cover 13 is matched and installed with a lower perspective window 131; at the same time, the tank upper cover 12 is also matched and installed with an upper layer pressurized joint 122 protruding upward and connected to the inner cavity of the fluid forming tank body 11.

[0034] The fluid forming mold 2 is matched and fixedly installed in the middle inner cavity of the fluid forming tank body 11. By injecting the optical polymer liquid C into the fluid forming mold 2 (before the upper cover of the fluid forming tank body is sealed, the density matching liquid A is injected into the fluid forming tank body 11 to immerse the fluid forming mold 2, and the optical polymer liquid C is injected into the fluid forming mold 2 from the tank body opening), an annular surrounding surface with a diameter of 50-100 mm is formed inside the fluid forming mold 2, which is located in the center of the fluid forming tank body 11 and is fixed inside the fluid forming tank body 11. At this time, the fluid forming mold 2 filled with the optical polymer liquid C divides the inner cavity of the container 1 into an upper sealed cavity 101 and a lower sealed cavity 102, and the upper sealed cavity 101 and the lower sealed cavity 102 both form sealed cavities; the upper layer pressure joint 122 is connected to the upper sealed cavity 101, and the lower layer pressure joint 113 is connected to the lower sealed cavity 102.

[0035] During operation, upper density-matching liquid A is injected into the upper sealed cavity 101 through the upper pressure joint 122, and lower density-matching liquid B is injected into the lower sealed cavity 102 through the lower pressure joint 113, so that the fluid forming mold 2 is completely immersed in the upper density-matching liquid A and the lower density-matching liquid B. Optical polymer liquid C is formed into a lens shape with a diameter of 50-100 mm in the fluid forming mold 2. After forming, the optical polymer liquid C is cured by heat or UV light to form an optical lens with a refractive index of 1.5-1.8, which is used as an eyeglass blank. Curing device 3 is selected based on the curing conditions of optical polymer liquid C to cure the optical polymer liquid C in the fluid forming mold 2. The upper density-matching liquid A and the lower density-matching liquid B have the same density as the optical polymer liquid C and do not chemically react with the optical polymer liquid C, thus not affecting the normal curing of the optical polymer liquid C.

[0036] The upper perspective window 121 and the lower perspective window 131 are both made of highly transparent glass. When using ultraviolet light to cure the optical polymer liquid C, the ultraviolet lamp irradiates the optical polymer liquid C in the fluid forming mold 2 through the upper perspective window 121 and the lower perspective window 131. When using heat to cure the optical polymer liquid C, the hot water in the side wall sandwich structure 110 of the fluid forming tank body 11 is used to heat and cure the optical polymer liquid C.

[0037] The present invention adjusts the upper and lower curved surfaces of the optical lens formed after the optical polymer liquid C is cured by regulating the pressure of the upper density matching liquid A and the lower density matching liquid B in the upper sealed cavity 101 and the lower sealed cavity 102. By adjusting the amount of the upper density matching liquid A and the lower density matching liquid B injected into the upper sealed cavity 101 and the lower sealed cavity 102, different pressure differences are formed in the upper sealed cavity 101 and the lower sealed cavity 102, thereby controlling the upper and lower shapes of the optical lens. The upper density matching liquid A and the lower density matching liquid B have the same density as the optical polymer liquid C, do not undergo any chemical reaction with the optical polymer liquid C, and do not affect the normal curing of the optical polymer liquid C.

[0038] The present invention uses heat to cure the optical polymer liquid C. The curing device 3 is a water bath heating pot. The container 1 containing the fluid forming mold 2, the upper density matching liquid A and the lower density matching liquid B, and the optical polymer liquid C is immersed in the water bath heating pot for heating. Circulating hot water is injected into the side wall sandwich structure 110 of the fluid forming tank body 11 through the upper circulating water inlet and outlet joints 111 and the lower circulating water inlet and outlet joints 112. When heat is used to cure the optical polymer liquid C, the hot water in the side wall sandwich structure 110 of the fluid forming tank body 11 is used to heat and cure the optical polymer liquid C. Ultraviolet light is used to cure the optical polymer liquid C. During curing, an ultraviolet curing lamp is used to uniformly irradiate the optical polymer liquid C to cure it.

[0039] The present invention will be further described below with reference to specific embodiments.

[0040] like Figure 1 Optical polymer liquid C uses PDMS (polydimethylsiloxane), with the chemical formula (C2H6OSi)n. After mixing the main components of PDMS with a curing agent, it cures at 60°C for 4 hours. Water and varying concentrations of glycerol are mixed to create upper density-matching liquid A and lower density-matching liquid B. This combination can achieve any density between 0.997 g / mL for water and 1.263 g / mL for pure glycerol.

[0041] The optical polymer liquid C is injected into the fluid forming mold 2. At this time, the fluid forming mold 2 filled with liquid divides the inner cavity of the container 1 into an upper sealed cavity 101 and a lower sealed cavity 102. The upper sealed cavity 101 and the lower sealed cavity 102 form a sealed cavity.

[0042] An annular fluid forming mold 2 with a diameter of 70 mm and a height of 10 mm is selected. An annular surrounding surface with a diameter of 70 mm is formed inside the fluid forming mold 2 , which is located in the center of the container 1 and fixed inside the container 1 .

[0043] The optical polymer liquid with a density of ρ is injected into the fluid forming mold 2 with a radius of R0 and a vertical thickness of d. The optical polymer liquid C is pinned to the edge of the fluid forming mold 2, axially symmetrical, and the liquid interface at the top and bottom is represented by h t and h b , under microgravity conditions, the potential energy term disappears and the surface is symmetrical (h t =h b ).

[0044] Then the energy of the system can be expressed as:

[0045]

[0046] Volume constraints:

[0047]

[0048] In the above formula, γ is the interfacial energy between the two liquids, λ is the Lagrange multiplier, and Δρ=|ρ lens -ρ im The left side of the expression represents the mean curvature of the surface, a constant that is determined by the volume of the injected liquid. For a circular boundary, the interface is a spherical cap. As shown above, the target shape can be achieved by varying the injected volume.

[0049] And the shape of each interface can be described as:

[0050]

[0051] The upper density matching liquid A and the lower density matching liquid B are respectively injected into the upper sealed cavity 101 and the lower sealed cavity 102, and the amount of the upper density matching liquid A and the lower density matching liquid B injected is adjusted. The pressure of the upper density matching liquid A and the lower density matching liquid B in the upper sealed cavity 101 and the lower sealed cavity 102 is regulated to adjust the upper and lower curved surfaces of the optical lens formed after the optical polymer liquid C is cured.

[0052] The optical polymer liquid C is heated and solidified to form a smooth lens with a smooth surface.

[0053] In some embodiments, the optical polymer liquid C is cured using light. In this case, the curing device 3 uses an ultraviolet curing lamp, which evenly irradiates the optical polymer liquid C to uniformly cure it.

[0054] In some embodiments, the pressure difference between the upper density matching liquid A and the lower density matching liquid B can be controlled by adjusting the liquid level heights of the upper density matching liquid A and the lower density matching liquid B in the upper sealed cavity 101 and the lower sealed cavity 102 .

[0055] like Figure 2In the use of the fluid forming mold 2, the optical polymer liquid C is also selected to use PDMS.

[0056] The optical polymer liquid C is injected into the fluid forming mold 2. At this time, the fluid forming mold 2 filled with liquid divides the inner cavity of the fluid forming tank body 11 into an upper sealed cavity 101 and a lower sealed cavity 102. The upper sealed cavity 101 and the lower sealed cavity 102 form a sealed cavity.

[0057] An annular fluid forming mold 2 with a diameter of 70 mm and a height of 10 mm is selected, and an annular surrounding surface with a diameter of 70 mm is formed inside the fluid forming mold 2 .

[0058] The upper density matching liquid A and the lower density matching liquid B are respectively injected into the upper sealed cavity 101 and the lower sealed cavity 102 through the upper pressure joint 122 and the lower pressure joint 113, and the amount of the upper density matching liquid A and the lower density matching liquid B injected is adjusted to regulate the pressure of the upper density matching liquid A and the lower density matching liquid B in the upper sealed cavity 101 and the lower sealed cavity 102, and adjust the upper and lower curved surfaces of the optical lens formed after the optical polymer liquid C is cured.

[0059] Hot water at 60°C is continuously circulated in the sandwich structure of the side wall of the fluid forming tank 11 through the upper circulating water inlet and outlet joints 111 and the lower circulating water inlet and outlet joints 112 to heat the temperature of the upper density matching liquid A, the lower density matching liquid B in the fluid forming tank 11 and the optical polymer liquid C in the fluid forming mold 2.

[0060] After heating for a period of time, the optical polymer liquid C solidifies to form a smooth lens with a smooth surface.

[0061] In some embodiments, the optical polymer liquid C is cured using light, and an ultraviolet curing lamp is used to uniformly irradiate the optical polymer liquid C through the upper perspective window 121 and the lower perspective window 131 to uniformly cure the optical polymer liquid C.

[0062] The present invention solves the problem that the complexity of the manufacturing process and the required professional equipment hinder the rapid prototyping of optical lenses. The rapid prototyping of lenses can be achieved without grinding and surface polishing. The mirror surface shape presented by the optical liquid can be changed by the size of the fluid forming mold, the volume of the optical polymer liquid and the pressure of the density matching liquid in the upper and lower sealed cavities.

[0063] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for direct molding of an optical lens based on fluid forming, characterized in that: First, a container (1), a fluid forming mold (2), a density matching liquid and an optical polymer liquid (C) are prepared; then, the fluid forming mold (2) is fixed at the center of the container (1), and the optical polymer liquid (C) is injected into the fluid forming mold (2). At this time, the fluid forming mold (2) filled with the optical polymer liquid (C) divides the inner cavity of the container (1) into an upper sealed cavity (101) and a lower sealed cavity (102); then, the density matching liquid is injected into the upper sealed cavity (101) and the lower sealed cavity (102) so that the fluid forming mold (2) is completely immersed in the density matching liquid, and the optical polymer liquid (C) and the density matching liquid are used to form an optical lens by quickly forming and curing in the fluid forming mold (2).

2. The method for direct forming of an optical lens based on fluid forming according to claim 1, wherein: An upper density matching liquid (A) is injected into the upper sealed cavity (101), and a lower density matching liquid (B) is injected into the lower sealed cavity (102); the surface shape of the optical lens is controlled by respectively adjusting the amount of the upper density matching liquid (A) injected into the upper sealed cavity (101) and the amount of the density matching liquid (B) injected into the lower sealed cavity (102) to form different pressure differences between the upper sealed cavity (101) and the lower sealed cavity (102), thereby controlling the upper and lower surface shapes of the optical lens.

3. The method for direct forming of an optical lens based on fluid forming according to claim 1, wherein: The density matching liquid has the same density as the optical polymer liquid (C); and no chemical reaction occurs between the density matching liquid and the optical polymer liquid (C).

4. The method for directly forming an optical lens based on fluid forming according to claim 1, wherein: The optical polymer liquid (C) is injected into the fluid forming mold (2) immersed in the density matching liquid to form a lens shape with a diameter of 50-100 mm.

5. The method for direct forming of an optical lens based on fluid forming according to claim 1, wherein: The formed optical polymer liquid (C) is solidified by a solidification device (3); and the optical polymer liquid (C) forms an optical lens with a refractive index of 1.5-1.8 after solidification.

6. The method for directly forming an optical lens based on fluid forming according to claim 5, wherein: The curing device (3) uses a water bath heating pot to immerse the container (1) containing the fluid forming mold (2), the density matching liquid, and the optical polymer liquid (C) in the water bath heating pot for heating, so as to cure the optical polymer liquid (C).

7. The method for direct forming of an optical lens based on fluid forming according to claim 1, wherein: The formed optical polymer liquid (C) can also be cured by heating or UV curing. When UV curing the optical polymer liquid (C), a UV curing lamp is used to uniformly irradiate the optical polymer liquid (C) to cure it.

8. The method for directly molding an optical lens based on fluid forming according to claim 1, wherein: The container (1) is a closed can-shaped container, the upper end of which is provided with an upper pressure joint (122) communicating with the upper sealed cavity (101), and the lower end of which is provided with a lower pressure joint (113) communicating with the lower sealed cavity (102); at the same time, the side wall of the container (1) is a sandwich structure (110), and the upper end side wall and the lower end side wall of the container (1) are also respectively matched with an upper circulating water inlet and outlet joint (111) and a lower circulating water inlet and outlet joint (112) communicating with the sandwich structure (110).

9. The method for directly molding an optical lens based on fluid forming according to claim 8, wherein: The container (1) comprises a fluid-formed tank body (11), a tank body upper cover (12) and a tank body lower cover (13); The top and bottom of the fluid-formed tank (11) are both open, and the sidewalls are the sandwich structure (110); The upper circulating water inlet and outlet joint (111) is matched and arranged on one side of the upper end of the fluid forming tank body (11); the lower circulating water inlet and outlet joint (112) is matched and arranged on one side of the lower end of the fluid forming tank body (11); and the lower layer pressurizing joint (113) is matched and arranged on the other side of the lower end of the fluid forming tank body (11); The tank body upper cover (12) and the tank body lower cover (13) are respectively matched and installed at the openings of the top and bottom of the fluid forming tank body (11) to close the fluid forming tank body (11).

10. The method for directly forming an optical lens based on fluid forming according to claim 9, wherein: An upper perspective window (121) is mounted in the central area of ​​the tank upper cover (12); A lower perspective window (131) is mounted in the central area of ​​the tank body lower cover (13); The upper layer pressurizing joint (122) is matched and arranged on the tank upper cover (12).

Images