Sealing structure and method suitable for high-temperature and high-pressure vacuum equipment

Abstract

The invention discloses a sealing structure and method suitable for high-temperature and high-pressure vacuum equipment, and belongs to the technical field of hypersonic wind tunnel design. The problem that an existing sealing part cannot achieve a good sealing effect or causes destructive damage in the high-temperature, high-pressure and vacuum state, and consequently the sealing part cannot be used is solved. The device comprises a front-end pipeline, an outer side soft seal, an inner side hard seal, a rear-end pipeline, a first inner sleeve and a second inner sleeve, the first inner sleeve is sleeved with the front-end pipeline, the second inner sleeve is sleeved with the rear-end pipeline, the front-end pipeline is connected with the rear-end pipeline, and the outer side soft seal and the inner side hard seal are arranged between the front-end pipeline and the rear-end pipeline. The sealing structure and method suitable for the high-temperature and high-pressure vacuum equipment can be applied to pipe sections with relative movement, and long-term repeated application of sealing under the high-temperature, high-pressure and vacuum working conditions is achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of hypersonic wind tunnel design, and in particular relates to a sealing structure and method suitable for high-temperature and high-pressure vacuum equipment. Background Art

[0002] As a large-scale ground wind tunnel test facility aimed at research and technical verification of hypersonic aircraft power and related issues, the main structure of the wind tunnel consists of an air inlet pipeline and pressure regulating system, a heater, a high-temperature pressure regulating stop valve, a stabilization section, a nozzle, a test cabin, an ejection system, a sub-expansion section and a vacuum branch.

[0003] When the wind tunnel is in operation, the pipeline from the rear end of the heater to the front end of the test chamber must withstand the erosion of high-temperature and high-pressure airflow. When vacuum injection is used, this section of the pipeline needs to withstand vacuum conditions.

[0004] Octagonal gaskets are often used to seal pipeline flanges that are subjected to high temperature and high pressure. When the pressure of the medium in the pipeline increases, the plastic deformation caused by the axial compression of the octagonal gasket makes the gasket itself closer to the outside of the groove, achieving a sealing effect. However, this type of sealing will cause the flange and the connecting bolts to deform, resulting in relative separation of the sealing surface. Therefore, the octagonal gasket cannot be reused multiple times on sections with relative movement; at the same time, the octagonal gasket cannot produce a good sealing effect when the internal high vacuum state is in place.

[0005] Pipe flanges that are subjected to high pressure / vacuum cycle conditions usually use flexible gaskets, such as rubber, to achieve sealing. However, rubber cannot withstand high temperature conditions and will be destructively damaged under high temperature conditions, making it unusable.

[0006] Therefore, the present application proposes a sealing structure and method suitable for high temperature and high pressure vacuum equipment to solve the above problems. Summary of the invention

[0007] The purpose of the present invention is to solve the problem that the existing sealing components cannot achieve a good sealing effect or cause destructive damage under high temperature, high pressure and vacuum conditions, resulting in the seal being unusable. A brief overview of the present invention is given below to provide a basic understanding of certain aspects of the present invention. It should be understood that this overview is not an exhaustive overview of the present invention. It is not intended to identify the key or important parts of the present invention, nor is it intended to limit the scope of the present invention.

[0008] The technical solution of the present invention:

[0009] Solution 1: A sealing structure suitable for high-temperature and high-pressure vacuum equipment, including a front-end pipeline, an outer soft seal, an inner hard seal, a rear-end pipeline, a first inner sleeve and a second inner sleeve, the first inner sleeve is sleeved in the front-end pipeline, the second inner sleeve is sleeved in the rear-end pipeline, the front-end pipeline is connected to the rear-end pipeline, and an outer soft seal and an inner hard seal are arranged between the front-end pipeline and the rear-end pipeline.

[0010] Furthermore, the front-end pipeline is connected to the rear-end pipeline by a screw, and threaded connectors are respectively threadedly connected to both ends of the screw, the inner side of one threaded connector contacts the front-end pipeline, and the inner side of the other threaded connector contacts the rear-end pipeline.

[0011] Furthermore, the outer soft seal is a rubber seal, and the inner hard seal is a metal seal.

[0012] Furthermore, the outer soft seal is a fluororubber sealing gasket, and the inner hard seal is a copper sealing gasket.

[0013] Furthermore, the first inner sleeve is connected to the front-end pipeline via a connecting piece, and the second inner sleeve is connected to the rear-end pipeline via a connecting piece.

[0014] Furthermore, the front-end pipeline and the rear-end pipeline are connected in an overlapping manner, and the overlapping parts of the front-end pipeline and the rear-end pipeline are staggered to form a labyrinth seal.

[0015] Solution 2: A sealing method applicable to high temperature and high pressure vacuum equipment, which is implemented based on the sealing structure applicable to high temperature and high pressure vacuum equipment described in Solution 1, and includes the following steps:

[0016] Step 1: Determine the relevant parameters of the first inner sleeve and the second inner sleeve. For different temperatures, the first inner sleeve and the second inner sleeve are made of alloy structural steel, stainless steel or high-temperature alloy. A gap is left at the connection between the first inner sleeve and the second inner sleeve. The gap is larger than the thermal expansion of the structural deformation, and the gap range is 0.1mm to 1mm.

[0017] Step 2: Determine the spatial parameters of the overlap between the first inner sleeve and the second inner sleeve, set the overlap between the first inner sleeve and the second inner sleeve as the radiation zone, and according to the flow temperature of the medium, the range of the radiation zone is between 5mm and 15mm;

[0018] Step 3: Determine the parameters of the inner hard seal, and select a metal material as the material of the inner hard seal according to the temperature radiated to the inner hard seal;

[0019] Step 4: Determine the parameters of the outer soft seal. The outer soft seal needs to have a deformation amount greater than 1mm. Select rubber sealing material as the sealing material of the outer soft seal.

[0020] The present invention has the following beneficial effects:

[0021] 1. A sealing structure suitable for high-temperature and high-pressure vacuum equipment of the present invention can be applied to a pipe section with relative motion to achieve long-term repeated application of the seal under high-temperature, high-pressure and vacuum conditions. The outer soft seal and the inner hard seal at the connection between the front-end pipeline and the rear-end pipeline are not on the same plane, forming a labyrinth seal to achieve a better sealing effect, while also facilitating the processing control of different gaps.

[0022] 2. The present invention is a sealing structure suitable for high-temperature and high-pressure vacuum equipment. The outer soft seal adopts rubber seal, and the elasticity of rubber is used to achieve the effect of secondary sealing and vacuum sealing. The inner hard seal adopts metal seal so that the first inner sleeve and the second inner sleeve can expand due to heat without affecting the effect of metal sealing. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a cross-sectional view of a sealing structure suitable for high temperature and high pressure vacuum equipment;

[0024] Figure 2 It is a cross-sectional view of the inner hard seal structure;

[0025] Figure 3 It is a cross-sectional view of the outer soft seal structure.

[0026] In the figure: 1-front end pipeline, 2-threaded connector, 3-outer soft seal, 4-inner hard seal, 5-rear end pipeline, 6-first inner sleeve, 7-connector, 8-screw, 9-second inner sleeve. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is described below by the specific embodiments shown in the accompanying drawings. However, it should be understood that these descriptions are only exemplary and are not intended to limit the scope of the present invention. In addition, in the following description, the description of well-known structures and technologies is omitted to avoid unnecessary confusion of the concept of the present invention.

[0028] The connection mentioned in the present invention is divided into fixed connection and detachable connection. The fixed connection (i.e., non-detachable connection) includes but is not limited to conventional fixed connection methods such as folding connection, rivet connection, bonding connection and welding connection. The detachable connection includes but is not limited to conventional detachable methods such as threaded connection, snap connection, pin connection and hinge connection. When the specific connection method is not clearly defined, it is assumed that at least one connection method can always be found in the existing connection methods to achieve the function. Those skilled in the art can choose according to their needs. For example: welding connection is selected for fixed connection, and hinge connection is selected for detachable connection.

[0029] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0030] Embodiment 1, combination Figure 1-Figure 3 To illustrate the present embodiment, a sealing structure suitable for high-temperature and high-pressure vacuum equipment is provided in the present embodiment, including a front-end pipeline 1, an outer soft seal 3, an inner hard seal 4, a rear-end pipeline 5, a first inner sleeve 6 and a second inner sleeve 9. The first inner sleeve 6 is sleeved inside the front-end pipeline 1, and the second inner sleeve 9 is sleeved inside the rear-end pipeline 5. The front-end pipeline 1 is connected to the rear-end pipeline 5, and an outer soft seal 3 and an inner hard seal 4 are arranged between the front-end pipeline 1 and the rear-end pipeline 5.

[0031] In order to avoid the common seals not being able to be applied to high temperature, high pressure and vacuum conditions at the same time, a double-layer design is designed in which an outer soft seal 3 and an inner hard seal 4 are used together. The inner hard seal 4 is subjected to high temperature and high pressure, and the outer soft seal 3 is subjected to vacuum. The first inner sleeve 6 and the second inner sleeve 9 are connected in an overlapping manner, and a labyrinth seal is formed by structural interlacing at the overlapping position, and the influence of temperature is reduced by the design of the cavity.

[0032] The front-end pipeline 1 and the rear-end pipeline 5 are processed with through holes of the same aperture. The through holes on the front-end pipeline 1 and the rear-end pipeline 5 are aligned, and the screw 8 is passed through the through holes of the front-end pipeline 1 and the rear-end pipeline 5, so that the screw 8 establishes a connection relationship between the front-end pipeline 1 and the rear-end pipeline 5. The two ends of the screw 8 are respectively arranged beyond the front-end pipeline 1 and the rear-end pipeline 5, and then the threaded connectors 2 are respectively screwed into the two ends of the screw 8. The threaded connector 2 is a nut. The two ends of the screw 8 are locked by the threaded connector 2 to complete the connection and fixation of the front-end pipeline 1 and the rear-end pipeline 5.

[0033] The inner hard seal 4 adopts metal sealing. Different metal materials are selected according to the different maximum temperatures of the internal circulating airflow. Using this design structure, the airflow temperature is within 650°C, and the sealing effect under high pressure can be achieved through metal extrusion deformation. In this embodiment, the inner hard seal 4 adopts a copper sealing gasket made of copper material. After the front end pipeline 1 and the rear end pipeline 5 are connected, the size of the inner hard seal groove for installing the inner hard seal 4 is smaller than the metal size of the inner hard seal 4, ensuring that the metal is squeezed before contacting the pipe body. At the same time, the thermal expansion of the first inner sleeve 6 and the second inner sleeve 9 does not affect the metal sealing effect.

[0034] The outer soft seal 3 adopts a rubber seal, and uses the elasticity of rubber to achieve the effects of secondary sealing and vacuum sealing. In this embodiment, the outer soft seal 3 adopts a fluororubber sealing gasket made of fluororubber material. The gap left between the front end pipeline 1 and the rear end pipeline 5 at the outer soft seal 3 is larger than the sealing groove of the inner hard seal 4, avoiding contact of the sealing surface caused by thermal expansion, and also avoiding simultaneous contact between this place and the inner hard seal 4, which would cause the seal at this place to fail.

[0035] The outer soft seal 3 is at the outer circle of the inner hard seal 4, and the outer soft seal 3 and the inner hard seal 4 are not in the same plane, forming a labyrinth seal to achieve a better sealing effect and facilitate processing control of different gaps.

[0036] Embodiment 2, combined Figure 1-Figure 3 This embodiment is described. A sealing method for high-temperature and high-pressure vacuum equipment in this embodiment includes the following steps:

[0037] Step 1: Determine the relevant parameters of the first inner sleeve 6 and the second inner sleeve 9. For different temperatures, the first inner sleeve 6 and the second inner sleeve 9 are made of alloy structural steel, stainless steel or high-temperature alloy. A gap is left at the connection between the first inner sleeve 6 and the second inner sleeve 9. The gap is larger than the thermal expansion of the structural deformation, and the gap range is 0.1mm to 1mm.

[0038] Step 2: Determine the spatial parameters of the overlap between the first inner sleeve 6 and the second inner sleeve 9, set the overlap between the first inner sleeve 6 and the second inner sleeve 9 as the radiation zone, and according to the flow temperature of the medium, the range of the radiation zone is between 5mm and 15mm;

[0039] Step 3: Determine the parameters of the inner hard seal 4. According to the temperature radiated to the inner hard seal 4, select a metal material as the material of the inner hard seal 4. In this embodiment, the inner hard seal 4 uses a copper sealing gasket with a compression amount greater than 0.5 mm.

[0040] Step 4: Determine the parameters of the outer soft seal 3. The outer soft seal 3 needs to have a deformation amount greater than 1 mm. Select a rubber sealing material as the sealing material of the outer soft seal 3. In this embodiment, a fluororubber sealing pad made of fluororubber is selected as the sealing material of the outer soft seal 3.

[0041] When the internal gas is of high temperature and high pressure, the copper sealing gasket used in the inner hard seal 4 will produce thermal expansion, which will increase the original extrusion deformation. The internal gas can basically not reach the outer soft seal 3. After a very small amount of gas overflows, the fluororubber sealing gasket of the outer soft seal 3 will deform to isolate the internal and external gases.

[0042] When the internal gas is vacuum, the internal pressure is low, and the external normal temperature gas will enter the interior, and the external soft seal 3 will achieve the effect of isolating the internal and external gases.

[0043] This embodiment is only an exemplary description of the present invention and does not limit its protection scope. Those skilled in the art may also make partial changes thereto. As long as they do not exceed the spirit of the present invention, they are within the protection scope of the present invention.

Claims

1. A sealing structure suitable for high temperature and high pressure vacuum equipment, characterized in that: The invention comprises a front-end pipeline (1), an outer soft seal (3), an inner hard seal (4), a rear-end pipeline (5), a first inner sleeve (6) and a second inner sleeve (9); the first inner sleeve (6) is sleeved inside the front-end pipeline (1), the second inner sleeve (9) is sleeved inside the rear-end pipeline (5), the front-end pipeline (1) is connected to the rear-end pipeline (5), and an outer soft seal (3) and an inner hard seal (4) are arranged between the front-end pipeline (1) and the rear-end pipeline (5).

2. A sealing structure suitable for high temperature and high pressure vacuum equipment according to claim 1, characterized in that: The front-end pipeline (1) and the rear-end pipeline (5) are connected via a screw (8), and threaded connectors (2) are respectively threadedly connected at both ends of the screw (8), the inner side surface of one threaded connector (2) contacts the front-end pipeline (1), and the inner side surface of the other threaded connector (2) contacts the rear-end pipeline (5).

3. A sealing structure suitable for high temperature and high pressure vacuum equipment according to claim 2, characterized in that: The outer soft seal (3) is a rubber seal, and the inner hard seal (4) is a metal seal.

4. A sealing structure suitable for high temperature and high pressure vacuum equipment according to claim 3, characterized in that: The outer soft seal (3) is a fluororubber seal pad, and the inner hard seal (4) is a copper seal pad.

5. A sealing structure suitable for high temperature and high pressure vacuum equipment according to claim 4, characterized in that: The first inner sleeve (6) is connected to the front-end pipeline (1) via a connecting piece (7), and the second inner sleeve (9) is connected to the rear-end pipeline (5) via a connecting piece (7).

6. The sealing structure suitable for high temperature and high pressure vacuum equipment according to claim 5, characterized in that: The front-end pipeline (1) and the rear-end pipeline (5) are connected in an overlapping manner, and the overlapping parts of the front-end pipeline (1) and the rear-end pipeline (5) are staggered to form a labyrinth seal.

7. A sealing method applicable to high temperature and high pressure vacuum equipment, the method is implemented by relying on the sealing structure applicable to high temperature and high pressure vacuum equipment as claimed in claim 6, characterized in that: The following steps are involved: Step 1: Determine the relevant parameters of the first inner sleeve (6) and the second inner sleeve (9). For different temperatures, the first inner sleeve (6) and the second inner sleeve (9) are made of alloy structural steel, stainless steel or high-temperature alloy. A gap is left at the connection between the first inner sleeve (6) and the second inner sleeve (9). The gap is larger than the thermal expansion of the structural deformation, and the gap range is 0.1 mm to 1 mm. Step 2: Determine the spatial parameters of the overlap between the first inner sleeve (6) and the second inner sleeve (9), set the overlap between the first inner sleeve (6) and the second inner sleeve (9) as a radiation zone, and according to the flow temperature of the medium, the range of the radiation zone is between 5 mm and 15 mm; Step 3: Determine the parameters of the inner hard seal (4), and select a metal material as the material of the inner hard seal (4) according to the temperature radiated to the inner hard seal (4); Step 4: Determine the parameters of the outer soft seal (3). The outer soft seal (3) needs to have a deformation amount greater than 1 mm. Select a rubber sealing material as the sealing material of the outer soft seal (3).

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