CN115929904A - An open sealing structure for ultra-high pressure sealing of large-diameter shells - Google Patents

Abstract

The invention relates to an open sealing structure for ultra-high pressure sealing of a large-diameter shell, belonging to the field of static strength assessment and testing of aerospace products; the sealing flange is coaxially arranged on the top of the external aerospace product; thickened retaining ring and O-shaped rubber The ring is set at the joint between the sealing flange and the external aerospace product; after the sealing flange and the external aerospace product are docked, the fastener passes through the sealing flange and the external aerospace product from top to bottom in turn, and is screwed and fixed; the sealing method There is a nozzle on the top of the flange, which communicates with the inner cavity of the external aerospace product, and is used for filling and discharging liquid during the hydraulic strength test; a handle is provided on the top of the sealing flange, which is used for lifting the sealing flange; , The thickened retaining ring can effectively reduce the shear damage force of the O-shaped rubber ring under ultra-high pressure conditions, improve the service life of the O-shaped rubber ring, and at the same time, avoid the phenomenon of "cold flow" itself.

Description

An open sealing structure for ultra-high pressure sealing of large-diameter shells

technical field

The invention belongs to the field of static strength assessment and testing of aerospace products, and relates to an open sealing structure used for ultra-high pressure sealing of large-diameter shells.

Background technique

In order to ensure the high performance of the rocket engine and the safety and reliability of the operation process, the pump casing and valve casing for aerospace products need to undergo a static strength assessment test after the manufacturing is completed to verify the static strength of the structure and the welding quality of the weld. The test pressure of the static strength assessment test is generally 1.2 to 1.5 times the working pressure of aerospace products, which puts more stringent requirements on the design of the ultra-high pressure sealing structure of the tooling. The existing large-scale pump casing sealing structure can basically be divided into end face seal and radial seal structure. The end face seal structure is generally used for sealing conditions below 30MPa; The polytetrafluoroethylene retaining ring prevents the O-ring from being extruded and damaged by the ultra-high pressure test medium, but the installation of the retaining ring with this structure is more difficult, and the polytetrafluoroethylene is often cut and installed, which reduces the structural strength of the retaining ring At the same time, if the thickness and size of the retaining ring are too large, it is often impossible to install. Therefore, under the large-diameter ultra-high pressure sealing condition of this sealing structure, the retaining ring is prone to "cold flow" phenomenon, resulting in the failure of the sealing structure. At the same time, this structure generally requires the seal assembly gap to be between 0.02mm and 0.1mm, which makes it difficult to disassemble and assemble, and the labor intensity of the test workers is high, which affects the test efficiency. Therefore, how to provide a new type of sealing structure with excellent machining processability, high assembly and disassembly efficiency, and strong ultra-high pressure sealing ability is a technical problem to be solved urgently by those skilled in the art.

Contents of the invention

The technical problem solved by the present invention is: to overcome the deficiencies of the prior art, and to propose an open sealing structure for ultra-high pressure sealing of large-caliber shells. During the test, the thickened retaining ring can effectively reduce the O The shearing destructive force of the O-shaped rubber ring can improve the service life of the O-shaped rubber ring, and at the same time, avoid the phenomenon of "cold flow" itself.

The technical solution of the present invention is:

An open sealing structure for ultra-high pressure sealing of large-diameter shells, including sealing flanges, thickened retaining rings, O-shaped rubber rings and fasteners; wherein, the external aerospace products are placed vertically upward; and the external aerospace products There are through holes in the axial direction; the sealing flange is coaxially arranged on the top of the external aerospace product; the thickened retaining ring and O-shaped rubber ring are arranged at the joint between the sealing flange and the external aerospace product; the connection between the sealing flange and the external aerospace product is completed Finally, the fastener passes through the sealing flange and the external aerospace product from top to bottom in turn, and is screwed and fixed.

In the above-mentioned open sealing structure for ultra-high pressure sealing of large-diameter shells, a nozzle is provided on the top of the sealing flange, and the nozzle is connected to the inner cavity of the external aerospace product, and is used for filling and discharging liquid during hydraulic strength tests ; There is a handle on the top of the sealing flange for lifting the sealing flange.

In the above-mentioned open sealing structure for ultra-high pressure sealing of large-diameter shells, the bottom of the sealing flange extends into the opening of the external aerospace product; the side wall of the sealing flange is provided with a sealing groove, thickened retaining ring, O The type rubber ring is embedded in the sealing groove.

In the above-mentioned open sealing structure for ultra-high pressure sealing of large-diameter housings, the section of the sealing groove is an L-shaped structure; the length of the short side of the L-shaped sealing groove is 75% of the diameter of the O-shaped rubber ring; The length of the long side of the L-shaped sealing groove is the sum of the thickness of the thickened retaining ring and 1.3 times the diameter of the O-shaped rubber ring.

In the above-mentioned open sealing structure for ultra-high pressure sealing of large-diameter casings, the diameter of the small end of the L-shaped sealing groove is matched with the inner diameter of the thickened retaining ring; when assembling, the entire ring of the thickened retaining ring Inserted into the L-shaped sealing groove, the thickness of the thickened retaining ring is equal to the length of the short side of the L-shaped sealing groove; the material of the thickened retaining ring is polytetrafluoroethylene.

In the above-mentioned open sealing structure for ultra-high pressure sealing of large-diameter housings, the inner diameter of the O-shaped rubber ring is smaller than the diameter of the small end of the L-shaped sealing groove, and the pre-stretching rate of the O-shaped rubber ring is GB/T3452 .3-2005 between 80% and 120% of the maximum pre-stretch ratio specified in Table 1A.

In the above-mentioned open sealing structure for ultra-high pressure sealing of large-diameter shells, the thickness of the thickened retaining ring is determined according to the static calculation results of the retaining ring. When the test pressure is less than 70 MPa, the thickness of the thickened retaining ring is 5mm; when the test pressure increases by 20MPa, the thickness of the thickened retaining ring increases by 1mm to ensure that the thickened retaining ring does not experience cold flow during the test.

In the above-mentioned open sealing structure for ultra-high pressure sealing of large-diameter shells, the thickened retaining ring is completely inserted into the sealing groove in the free-fitting state; Produce uniform plastic deformation to compensate for seal leakage gaps.

In the above-mentioned open sealing structure for ultra-high pressure sealing of large-diameter shells, the thickened retaining ring has a strong ability to compensate for the leakage gap of the seal under ultra-high pressure test conditions; therefore, the sealing flange and the external aerospace The assembly clearance of the product is controlled at 0.3mm on one side.

In the above-mentioned open sealing structure for ultra-high pressure sealing of large-caliber housings, the small end at the entrance of the L-shaped sealing groove is an open structure, and there is no need to stretch the O-shaped rubber ring too much when installing it.

The beneficial effect of the present invention compared with prior art is:

(1) Through the structural design of the present invention, the entire ring of the thickened retaining ring is inserted into the sealing groove, which improves the structural strength of the thickened retaining ring itself, avoids the phenomenon of "cold flow" under ultra-high pressure conditions, and improves The installation efficiency of the sealing structure reduces the labor intensity of workers;

(2) The present invention quantifies the thickness design criterion of the thickened retaining ring, reduces the difficulty of sealing structure design, and improves design efficiency;

(3) The small end of the "L" sealing groove of the present invention is an open structure. When installing the O-shaped rubber ring, it is not necessary to stretch it too much, which reduces the phenomenon of twisting and misalignment during installation of the O-shaped rubber ring; Ensure that the O-shaped rubber ring is reliably tightened on the inner diameter of the L-shaped sealing groove of the sealing flange to prevent the O-shaped rubber ring from falling off or deviation during installation;

(4) The present invention rationally sets the thickness of the thickened retaining ring (2), which can compensate for the assembly gap under ultra-high pressure conditions, and can avoid self-generating "cold flow" phenomenon; increasing the seal assembly gap can The difficulty for workers to install the sealing structure is effectively reduced, and the efficiency of disassembly and assembly of the sealing structure is improved.

Description of drawings

Fig. 1 is a schematic diagram of the open sealing structure of the present invention.

in the picture

1-Sealing flange; 2-Thickened retaining ring; 3-O-type rubber ring; 4-Fasteners.

Detailed ways

The present invention will be further elaborated below in conjunction with embodiment.

The present invention provides an open sealing structure for ultra-high pressure sealing of large-diameter shells. The sealing structure cancels the step at the entrance of the closed sealing groove of the traditional radial sealing structure, so the thickened retaining ring 2 can be completely ring-wrapped During the test, the ultra-high pressure fluid test medium acts on the O-ring 3, and the O-ring 3 tends to be squeezed out and damaged. Thickening the back-up ring 2 can effectively reduce the shear of the O-ring 3. Cut the destructive power, and avoid the "cold flow" phenomenon.

The open sealing structure, as shown in Figure 1, specifically includes a sealing flange 1, a thickened retaining ring 2, an O-shaped rubber ring 3 and a fastener 4; wherein, the external aerospace product is placed vertically upward; and the shaft of the external aerospace product There are through holes in the direction; the sealing flange 1 is coaxially arranged on the top of the external aerospace product; the thickened retaining ring 2 and the O-shaped rubber ring 3 are arranged at the joint between the sealing flange 1 and the external aerospace product; the sealing flange 1 and the external aerospace product After the docking of the aerospace product is completed, the fastener 4 passes through the sealing flange 1 and the external aerospace product sequentially from top to bottom, and is screwed and fixed. The top of the sealing flange 1 is provided with a nozzle, which communicates with the inner cavity of the external aerospace product, and is used for filling and discharging liquid during the hydraulic strength test; the top of the sealing flange 1 is provided with a handle for lifting the sealing flange 1.

When installing the structure, first check whether the thickened retaining ring 2 and the O-shaped rubber ring 3 are cracked, aged, etc., and whether the fastener 4 is deformed, cracked, damaged, etc., and if so, replace it. When installing this structure, first put the whole ring of the thickened retaining ring into the sealing groove, pass the upper end surface of the sealing groove to limit the position, then put the O-shaped rubber ring 3 on the shaft of the sealing groove, pass the end surface of the thickened retaining ring Carry out the limit, and finally, install the sealing flange and tighten all fasteners.

The bottom of the sealing flange 1 extends into the opening of the external aerospace product; the side wall of the sealing flange 1 is provided with a sealing groove, and the thickened retaining ring 2 and the O-shaped rubber ring 3 are embedded in the sealing groove. The section of the sealing groove is L-shaped structure; the length of the short side of the L-shaped sealing groove is 75% of the diameter of the O-shaped rubber ring 3; the length of the long side of the L-shaped sealing groove is 1.3 times the thickness of the thickened retaining ring 2 The sum of the rubber ring 3 wire diameters. The advantages of this sealing groove are: good machining processability and compact structure.

The diameter of the small end of the L-shaped sealing groove and the inner diameter of the thickened retaining ring 2 are matching dimensions; when assembling, the entire ring of the thickened retaining ring 2 is inserted into the L-shaped sealing groove, and the thickness of the thickened retaining ring 2 is consistent with the L-shaped seal The lengths of the short sides of the grooves are equal; the material of the thickened retaining ring 2 is polytetrafluoroethylene. The advantage of this sealing structure is that the entire circle of the thickened retaining ring 2 can be inserted into the sealing groove without cutting, and the structural strength of the thickened retaining ring 2 is improved.

The inner diameter of the O-shaped rubber ring 3 is smaller than the diameter of the small end of the L-shaped sealing groove, and the pre-stretching rate of the O-shaped rubber ring 3 is between 80% and 120% of the maximum pre-stretching rate specified in Table 1A of GB/T3452.3-2005 between. The advantage of this design is: to ensure that the O-shaped rubber ring 3 is reliably tightened on the inner diameter of the sealing flange 1L-type sealing groove, so as to prevent the O-shaped rubber ring 3 from falling off or wandering during installation.

The thickness of the thickened retaining ring 2 is determined according to the static calculation results of the retaining ring. When the test pressure is less than 70MPa, the thickness of the thickened retaining ring 2 is 5mm; when the test pressure increases by 20MPa, the thickness of the thickened retaining ring 2 increases by 1mm to ensure The thick retaining ring 2 does not experience cold flow during the test. The advantage of this structure is that it reduces the difficulty of sealing design and improves the reliability of ultra-high pressure sealing.

The thickened retaining ring 2 is fully inserted into the sealing groove in the free-fitting state; during the ultra-high pressure test, the thickened retaining ring 2 produces uniform plastic deformation along the circumferential direction to compensate for the seal leakage gap. The advantage of this structure is that it reduces the shearing force on the O-shaped rubber ring 3 under ultra-high pressure conditions, and improves the service life of the O-shaped rubber ring.

Since the thickened retaining ring 2 has a strong ability to compensate the sealing leakage gap under the ultra-high pressure test condition; therefore, the assembly gap between the sealing flange 1 and the external aerospace product is controlled at 0.3mm on one side. The advantage of this structure is that it improves the disassembly efficiency of the tooling and reduces the labor intensity of the test workers.

The small end at the entrance of the L-shaped sealing groove is an open structure, so there is no need to stretch it too much when installing the O-shaped rubber ring 3 . The advantage of this design is that when the O-shaped rubber ring 3 is installed, the possibility of twisting and misalignment occurs.

One of the technical solutions of the present invention is: the section of the sealing groove of the sealing flange 1 is approximately "L" shaped.

The advantages of the above technical solution are: the "L" shaped sealing groove has better machining processability;

The second technical solution of the present invention is: the material of the thickened retaining ring 2 is polytetrafluoroethylene, and the entire ring is inserted into the shaft of the sealing groove during assembly. When the test pressure is lower than 70MPa, the thickness of the retaining ring is 5mm. When the test pressure increases by 20Mpa, the thickness of the retaining ring increases by 1mm;

One of the advantages of the above-mentioned technical solution is: through the structural design, the entire ring of the thickened retaining ring 2 is inserted into the sealing groove, which improves the structural strength of the thickened retaining ring 2 itself, and avoids "cold cold" under ultra-high pressure conditions. The phenomenon of "flow" improves the installation efficiency of the sealing structure and reduces the labor intensity of workers.

The second advantage of the above-mentioned technical solution is: the thickness design criterion of the thickened retaining ring 2 is quantified, the difficulty of sealing structure design is reduced, and the design efficiency is improved

The third technical solution of the present invention is: the inner diameter of the O-shaped rubber ring 3 is smaller than the diameter of the small end of the L-shaped sealing groove, and its pre-stretching ratio should be the maximum pre-stretching ratio specified in Table 1A of GB/T3452.3-2005 Between 80%-120%.

The principle of the above technical solution is: the duration of the static strength assessment test at the component level is generally 5min-10min, therefore, increasing the pre-stretching rate to 120% of the maximum value specified in the national standard will not cause O-shaped rubber Circle 3 produces relaxation, distortion and other phenomena.

One of the advantages of the above technical solution is: the small end of the "L" sealing groove is an open structure, when installing the O-shaped rubber ring 3, it does not need to be stretched too much, which reduces the distortion of the O-shaped rubber ring 3 during installation , the phenomenon of installation deviation;

The second advantage of the above technical solution is to ensure that the O-shaped rubber ring 3 is reliably tightened on the inner diameter of the sealing flange 1L-shaped sealing groove, so as to prevent the O-shaped rubber ring 3 from falling off or deviation during installation;

The fourth technical solution of the present invention is: the assembly gap between the sealing flange 1, the thickened retaining ring 2 and aerospace products is controlled at about 0.3 mm on one side;

The principle of the above technical solution is: under the overpressure condition, the static pressure on the surface of the thickened retaining ring 2 is basically the same, so uniform plastic deformation will occur along the assembly sealing gap to compensate the gap. According to the above, setting the thickness of the thickened retaining ring 2 reasonably can not only make up for the assembly gap under ultra-high pressure conditions, but also avoid the phenomenon of "cold flow" itself.

Although the present invention has been disclosed as above with preferred embodiments, it is not intended to limit the present invention, and any person skilled in the art can use the methods disclosed above and technical content to analyze the present invention without departing from the spirit and scope of the present invention. Possible changes and modifications are made in the technical solution. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention, which do not depart from the content of the technical solution of the present invention, all belong to the technical solution of the present invention. protected range.

Claims (10)

1. The utility model provides an open seal structure that is used for sealed of heavy-calibre casing superhigh pressure which characterized in that: comprises a sealing flange (1), a thickening retainer ring (2), an O-shaped rubber ring (3) and a fastener (4); wherein the external space products are vertically placed upwards; and the external space product is axially provided with a through hole; the sealing flange (1) is coaxially arranged at the top end of an external aerospace product; the thickened retainer ring (2) and the O-shaped rubber ring (3) are arranged at the butt joint of the sealing flange (1) and an external aerospace product; after the sealing flange (1) is butted with an external aerospace product, the sealing flange (1) and the external aerospace product sequentially penetrate through the fastening piece (4) from top to bottom and are fixed in a threaded connection mode.

2. The open seal structure for ultra-high pressure sealing of a large diameter casing of claim 1, wherein: the top of the sealing flange (1) is provided with a filler neck which is communicated with an inner cavity of an external aerospace product and is used for filling and discharging liquid during a hydraulic strength test; the top of the sealing flange (1) is provided with a handle for hoisting the sealing flange (1).

3. The open seal structure for ultra-high pressure sealing of a large diameter casing according to claim 2, wherein: the bottom of the sealing flange (1) extends into an opening of an external aerospace product; the side wall of the sealing flange (1) is provided with a sealing groove, and a thickening retainer ring (2) and an O-shaped rubber ring (3) are embedded in the sealing groove.

4. The open seal structure for ultra-high pressure sealing of a large diameter casing according to claim 3, wherein: the section of the sealing groove is of an L-shaped structure; the length of the short side of the L-shaped sealing groove is 75% of the wire diameter of the O-shaped rubber ring (3); the length of the long edge of the L-shaped sealing groove is the sum of the thickness of the thickened retainer ring (2) and the wire diameter of the O-shaped rubber ring (3) which is 1.3 times of the wire diameter of the thickened retainer ring.

5. The open seal structure for ultra-high pressure sealing of a large diameter casing of claim 4, wherein: the diameter of the small end of the L-shaped sealing groove and the inner diameter of the thickened retainer ring (2) are matched in size; during assembly, the thickened retainer ring (2) is sleeved into the L-shaped sealing groove in a whole ring mode, and the thickness of the thickened retainer ring (2) is equal to the length of the short edge of the L-shaped sealing groove; the thickened retainer ring (2) is made of polytetrafluoroethylene.

6. The open seal structure for ultra-high pressure sealing of a large diameter casing according to claim 1, wherein: the inner diameter of the O-shaped rubber ring (3) is smaller than the diameter of the small end of the L-shaped sealing groove, and the pre-stretching rate of the O-shaped rubber ring (3) is 80% -120% of the maximum pre-stretching rate specified in GB/T3452.3-2005 Table 1A.

7. The open seal structure for ultra-high pressure sealing of a large diameter casing according to claim 1, wherein: the thickness of the thickened retainer ring (2) is determined according to the statics calculation result of the retainer ring, and when the test pressure is less than 70MPa, the thickness of the thickened retainer ring (2) is 5mm; every time the test pressure is increased by 20MPa, the thickness of the thickening check ring (2) is increased by 1mm, and the thickening check ring (2) is guaranteed not to have cold flow phenomenon in the test process.

8. The open seal structure for ultra-high pressure sealing of a large diameter casing of claim 7, wherein: the thickened retainer ring (2) is sleeved into the sealing groove in a whole ring under the freely assembled sleeve; during the ultrahigh pressure test, the thickening check ring (2) generates uniform plastic deformation along the circumferential direction to compensate the sealing leakage gap.

9. The open seal structure for ultra-high pressure sealing of a large diameter casing of claim 8, wherein: the assembly clearance between the sealing flange (1) and an external aerospace product is controlled to be 0.3mm on a single side.

10. The open seal structure for ultra-high pressure sealing of a large diameter casing of claim 5, wherein: the small end at the inlet of the L-shaped sealing groove is of an open structure.

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