CN214698708U - Seal structure of screw hole under low temperature, high pressure liquefied gas environment - Google Patents
Seal structure of screw hole under low temperature, high pressure liquefied gas environment Download PDFInfo
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- CN214698708U CN214698708U CN202120083813.7U CN202120083813U CN214698708U CN 214698708 U CN214698708 U CN 214698708U CN 202120083813 U CN202120083813 U CN 202120083813U CN 214698708 U CN214698708 U CN 214698708U
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Abstract
The utility model discloses a seal structure of screw hole under low temperature, high pressure liquefied gas environment, include: the screw rod, more than one second O-shaped ring and more than one gasket; the screw rod is integrally formed by more than two threaded rod sections with different outer diameters and a circular truncated cone section and a cylindrical section between every two adjacent threaded rod sections; two adjacent threaded rod sections are respectively a primary threaded rod section and a secondary threaded rod section, the small-diameter end of the circular truncated cone section is intersected with the primary threaded rod section, and a third step surface is arranged at the intersection; a fourth step surface is arranged at the intersection of the cylindrical section and the secondary threaded rod section; more than one second O-shaped ring is arranged on the cylindrical section of the screw rod; gaskets are arranged on the step surfaces between two adjacent threaded rod sections; the utility model discloses can enough adapt to low temperature, highly compressed liquefied gas environment, can conveniently dismantle and maintain again.
Description
Technical Field
The utility model belongs to the technical field of low temperature, high pressure equipment research and development are used, concretely relates to seal structure of screw hole under low temperature, the high pressure liquefied gas environment.
Background
The low-temperature high-pressure liquefied gas is gas with the temperature below 120K and the pressure not less than 1 MPa. Gases in the form of liquefied gases include Liquefied Natural Gas (LNG), liquid oxygen, liquid nitrogen, liquid hydrogen, liquid helium, and the like.
The sealing of threaded holes in low temperature, high pressure liquefied gas environments has been a major problem in the industry, and failure of sealing elements is a major cause of leakage. Like the production of LNG, liquid hydrogen, screw hole sealing failure not only can bring the waste of the energy in the transportation, can produce huge potential safety hazard moreover.
The existing thread sealing modes mainly comprise four modes:
firstly, a sealing effect is achieved by winding a thin hemp rope or spraying lead oil on threads, which is the most traditional mode; secondly, winding threads by using a polytetrafluoroethylene raw material belt, which is one of the most common modes at present; thirdly, coating the thread with sealant (le tai 243, GD414, etc.), and sealing after the sealant is dried; welding and sealing, and directly welding the bolt and the threaded connecting piece to play a role in sealing after the bolt is screwed down.
However, the existing thread sealing mode has the defects under the environment of low-temperature and high-pressure liquefied gas:
winding a thin hemp rope or spraying lead oil on the threads. The disadvantages of the mode are that the hemp and thick paint is easy to embrittle and lose efficacy in low-temperature environment, is not high-pressure resistant and has short service life.
And secondly, winding threads by using a polytetrafluoroethylene raw material belt. The method has good economy, simple operation and convenient construction, but the pressure resistance of the method is not more than 10MPa, the sealing effect at low temperature is poor, and the disassembly is difficult.
Thirdly, coating the sealing glue (le tai 243, GD414, etc.) on the thread for sealing. The method has extremely high requirement on the sealant, poor economy, short service life and difficult disassembly.
And fourthly, mechanical sealing. This method can be used without disassembly, but is not applicable in most cases.
SUMMERY OF THE UTILITY MODEL
In view of this, the utility model provides a seal structure of screw hole under low temperature, the high pressure liquefied gas environment can enough adapt to low temperature, highly compressed liquefied gas environment (temperature more than 20K, pressure below 70 MPa), can conveniently dismantle again and maintain.
The utility model discloses a realize through following technical scheme:
a seal structure of a threaded hole in a low-temperature and high-pressure liquefied gas environment is characterized in that the threaded hole is integrally formed by more than two threaded hole sections with different inner diameters and a circular truncated cone hole and a cylindrical hole between every two adjacent threaded hole sections, the two adjacent threaded hole sections are respectively a primary threaded hole and a secondary threaded hole, the inner diameter of the primary threaded hole is smaller than that of the secondary threaded hole, the small-diameter end of the circular truncated cone hole is intersected with the primary threaded hole, and a first step surface is arranged at the intersection; a second step surface is arranged at the intersection of the cylindrical hole and the secondary threaded hole;
the seal structure includes: the screw rod, more than one second O-shaped ring and more than one gasket;
the screw rod is integrally formed by more than two threaded rod sections with different outer diameters and a circular truncated cone section and a cylindrical section between every two adjacent threaded rod sections; the number of the threaded rod sections is equal to that of the threaded hole sections; two adjacent threaded rod sections are respectively a primary threaded rod section and a secondary threaded rod section, the outer diameter of the primary threaded rod section is smaller than that of the secondary threaded rod section, the small-diameter end of the circular truncated cone section is intersected with the primary threaded rod section, and a third step surface is arranged at the intersection; a fourth step surface is arranged at the intersection of the cylindrical section and the secondary threaded rod section;
the overall connection relationship is as follows: taking the connection between two adjacent threaded rod sections of the threaded rod and two adjacent threaded hole sections of the threaded hole as an example:
more than one second O-shaped ring is arranged on the cylindrical section of the screw rod; gaskets are arranged on the step surfaces between two adjacent threaded rod sections, and the number of the gaskets is equal to that of the threaded rod sections; a gasket at the third step surface between two adjacent threaded rod sections is a first gasket, and a gasket at the fourth step surface is a second gasket;
when a screw rod provided with a second O-shaped ring and a gasket is matched with the threaded hole, the primary threaded rod section of the screw rod is in threaded fit with the primary threaded hole of the threaded hole, the secondary threaded rod section of the screw rod is in threaded fit with the secondary threaded hole of the threaded hole, and the cylindrical section of the screw rod is matched with the cylindrical hole of the threaded hole; the circular truncated cone section of the screw rod is tightly attached to the circular truncated cone hole of the threaded hole to form conical surface sealing; the first gasket is tightly pressed between the first step surface of the threaded hole and the third step surface of the screw rod, and the second gasket is tightly pressed between the second step surface of the threaded hole and the fourth step surface of the screw rod to form axial seal; the second O-shaped ring is tightly attached to the cylindrical hole of the threaded hole to form radial sealing.
Further, still include first O type circle, first O type circle is installed on the outer periphery of the big footpath end of the round platform section of screw rod, and first O type circle with the round platform hole of screw hole closely laminates, forms radial seal.
Furthermore, the included angle between the generatrix of the circular truncated cone hole and the axis thereof is b; and the value range of b is 30-60 degrees;
the included angle between the generatrix of the circular table section and the axis thereof is a, the value range of a is 30-60 degrees, and the difference between a and b is not more than 1 degree.
Furthermore, the first O-shaped ring and the second O-shaped ring are made of fluororubber.
Furthermore, the thickness of the gasket is 2-3 mm, and the thickness error is not more than 0.1 mm.
Furthermore, the gasket is made of polytetrafluoroethylene.
Has the advantages that: the utility model is a five-stage step-by-step sealing structure, which can adapt to low-temperature and high-pressure liquefied gas environment (the temperature is above 20K, the pressure is below 70 MPa), and is convenient to disassemble and maintain; meanwhile, the sealing effect, the service life of the equipment and the safety of low-temperature and high-pressure equipment are improved; the manufacturing difficulty is moderate, the manufacturing cost is controllable, and the method has application prospect.
Drawings
FIG. 1 is a structural diagram of the present embodiment 1;
FIG. 2 is a structural diagram of this embodiment 2;
the sealing structure comprises a sealing ring, a first O-shaped ring, a second O-shaped ring, a first gasket, a second gasket, a screw rod, a first-level threaded rod section, a second-level threaded rod section, a circular truncated cone section and a circular truncated cone hole, wherein the sealing ring comprises 1-the first O-shaped ring, 2-the second O-shaped ring, 3-the first gasket, 4-the second gasket, 5-the screw rod, 6-the first-level threaded rod section, 7-the second-level threaded rod section, 8-the circular truncated cone section and 9-the circular truncated cone hole.
Detailed Description
The present invention will be described in detail below with reference to the accompanying drawings by way of examples.
Example 1:
the embodiment provides a sealing structure of a threaded hole in a low-temperature and high-pressure liquefied gas environment, and referring to fig. 1, the threaded hole of the embodiment is a two-stage threaded hole, the two-stage threaded hole is integrally formed by a first-stage threaded hole, a circular truncated cone hole 9, a cylindrical hole and a second-stage threaded hole in sequence, the inner diameter of the first-stage threaded hole is smaller than that of the second-stage threaded hole, the small-diameter end of the circular truncated cone hole 9 is intersected with the first-stage threaded hole, and a first step surface is arranged at the intersection; a second step surface is arranged at the intersection of the cylindrical hole and the secondary threaded hole; the included angle between the generatrix of the circular table hole 9 and the axis thereof is b; and the value range of b is 30-60 degrees;
the seal structure includes: the device comprises a first O-shaped ring 1, a second O-shaped ring 2, a first gasket 3, a second gasket 4 and a screw rod 5;
the screw 5 is a two-stage threaded bolt and is integrally formed by a first-stage threaded rod section 6, a circular truncated cone section 8, a cylindrical section and a second-stage threaded rod section 7 in sequence, the outer diameter of the first-stage threaded rod section 6 is smaller than that of the second-stage threaded rod section 7, the small-diameter end of the circular truncated cone section 8 is intersected with the first-stage threaded rod section 6, and a third step surface is arranged at the intersection; a fourth step surface is arranged at the intersection of the cylindrical section and the secondary threaded rod section 7; the outer circumferential surface of the large-diameter end of the circular table section 8 is provided with a first annular groove, and the outer circumferential surface of the cylindrical section is provided with a second annular groove; the included angle between the generatrix of the circular table section 8 and the axis thereof is a, the value range of a is 30-60 degrees, and the difference between a and b is not more than 1 degree; the pitch errors of the first-stage threaded rod section 6 and the second-stage threaded rod section 7 are controlled within 0.1 mm;
the first O-shaped ring 1 and the second O-shaped ring 2 are made of fluororubber;
the thicknesses of the first gasket 3 and the second gasket 4 are both 2-3 mm, and the thickness error is not more than 0.1 mm; the materials are all made of polytetrafluoroethylene with the same material;
the overall connection relationship is as follows: the first O-shaped ring 1 is arranged in a first annular groove of the screw rod 5, and the second O-shaped ring 2 is arranged in a second annular groove of the screw rod 5; the first gasket 3 is sleeved on a third step surface of the screw rod 5, and the second gasket 4 is sleeved on a fourth step surface of the screw rod 5;
when a screw rod 5 provided with a first O-shaped ring 1, a second O-shaped ring 2, a first gasket 3 and a second gasket 4 is matched with the threaded hole, a first-stage threaded rod section 6 of the screw rod 5 is in threaded fit with a first-stage threaded hole of the threaded hole, a second-stage threaded rod section 7 of the screw rod is in threaded fit with a second-stage threaded hole of the threaded hole, and a cylindrical section of the screw rod 5 is matched with a cylindrical hole of the threaded hole; the circular truncated cone section 8 of the screw rod 5 is tightly attached to the circular truncated cone hole 9 of the threaded hole to form conical surface sealing; the first gasket 3 is tightly pressed between the first step surface of the threaded hole and the third step surface of the screw rod 5, and the second gasket 4 is tightly pressed between the second step surface of the threaded hole and the fourth step surface of the screw rod 5, so that two axial seals are formed; the first O-shaped ring 1 is tightly attached to the circular truncated cone hole 9 of the threaded hole, and the second O-shaped ring 2 is tightly attached to the cylindrical hole of the threaded hole to form two radial seals; therefore, the bolt sealing structure of the present embodiment is a five-stage sealing structure with double threaded holes.
The working principle is as follows: when in low temperature, high pressure liquefied gas environment, the axial seal of first gasket 3 department at first plays main sealing effect, and after first gasket 3 damaged, then the sealed main sealing effect that begins of the conical surface of the round platform hole 9 of the round platform section 8 of screw rod 5 and screw hole, when the sealed back that damages of conical surface, then the radial seal of first O type circle 1 department begins to play main sealing effect, after first O type circle 1 damaged, the axial seal of second O type circle 2 department begins to play main sealing effect, after second O type circle 2 damaged, the axial seal of second gasket 4 department begins to play main sealing effect, until second gasket 4 destroyed, the condition that can not appear leaking gas after five-stage seal all destroyed promptly.
The threaded hole of the embodiment is not limited to a two-stage threaded hole, the corresponding screw 5 is not limited to a two-stage threaded bolt, and the threaded bolt can be applied to more than two stages of threaded holes by increasing the threaded rod section of the screw 5;
the number of the second O-rings 2 in this embodiment is not limited to one, and the number of the second O-rings may be increased according to the length of the cylindrical hole of the threaded hole, and the materials of the first O-ring 1 and the second O-ring 2 are not limited to fluororubber, and may be selected from other materials according to the working conditions;
the number of the first gasket 3 and the second gasket 4 of this embodiment is not limited to one, and can be according to the progression of the threaded hole is increased, and the material of the number of the first gasket 3 and the second gasket 4 is not limited to polytetrafluoroethylene, and other materials can be selected for use according to the working condition.
Example 2:
in this embodiment, on the basis of embodiment 1, referring to fig. 2, a first annular groove and a first O-ring 1 which are arranged on the outer circumferential surface of the large-diameter end of the circular table section 8 are omitted, so as to form a four-stage sealing structure of the threaded hole; the processing manufacturing difficulty and the manufacturing cost of this embodiment all can be low, but have reduced one-level seal structure, and factor of safety reduces, can adopt this kind of structure to low pressure, the higher equipment of temperature.
In summary, the above is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (6)
1. A seal structure of a threaded hole in a low-temperature and high-pressure liquefied gas environment is characterized in that the threaded hole is integrally formed by more than two threaded hole sections with different inner diameters and a circular truncated cone hole (9) and a cylindrical hole between every two adjacent threaded hole sections, the two adjacent threaded hole sections are respectively a primary threaded hole and a secondary threaded hole, the inner diameter of the primary threaded hole is smaller than that of the secondary threaded hole, the small-diameter end of the circular truncated cone hole (9) is intersected with the primary threaded hole, and a first step surface is arranged at the intersection; a second step surface is arranged at the intersection of the cylindrical hole and the secondary threaded hole;
characterized in that, the seal structure includes: the screw rod (5), more than one second O-shaped ring (2) and more than one gasket;
the screw (5) is integrally formed by more than two threaded rod sections with different outer diameters and a circular truncated cone section (8) and a cylindrical section between every two adjacent threaded rod sections; the number of the threaded rod sections is equal to that of the threaded hole sections; two adjacent threaded rod sections are respectively a primary threaded rod section (6) and a secondary threaded rod section (7), the outer diameter of the primary threaded rod section (6) is smaller than that of the secondary threaded rod section (7), the small-diameter end of the circular platform section (8) is intersected with the primary threaded rod section (6), and a third step surface is arranged at the intersection; a fourth step surface is arranged at the intersection of the cylindrical section and the secondary threaded rod section (7);
the overall connection relationship is as follows: taking the connection between two adjacent threaded rod sections of the threaded rod (5) and two adjacent threaded hole sections of the threaded hole as an example:
more than one second O-shaped ring (2) is arranged on the cylindrical section of the screw rod (5); gaskets are arranged on the step surfaces between two adjacent threaded rod sections, and the number of the gaskets is equal to that of the threaded rod sections; a gasket at the third step surface between two adjacent threaded rod sections is a first gasket (3), and a gasket at the fourth step surface is a second gasket (4);
when a screw rod (5) provided with a second O-shaped ring (2) and a gasket is matched with the threaded hole, a primary threaded rod section (6) of the screw rod (5) is in threaded fit with the primary threaded hole of the threaded hole, a secondary threaded rod section (7) of the screw rod is in threaded fit with the secondary threaded hole of the threaded hole, and a cylindrical section of the screw rod (5) is matched with a cylindrical hole of the threaded hole; the round table section (8) of the screw rod (5) is tightly attached to the round table hole (9) of the threaded hole to form conical surface sealing; the first gasket (3) is tightly pressed between a first step surface of the threaded hole and a third step surface of the screw rod (5), and the second gasket (4) is tightly pressed between a second step surface of the threaded hole and a fourth step surface of the screw rod (5) to form axial sealing; the second O-shaped ring (2) is tightly attached to the cylindrical hole of the threaded hole to form radial sealing.
2. The sealing structure of the threaded hole in the low-temperature and high-pressure liquefied gas environment according to claim 1, further comprising a first O-ring (1), wherein the first O-ring (1) is installed on the outer circumferential surface of the large-diameter end of the circular truncated cone section (8) of the screw rod (5), and the first O-ring (1) is tightly attached to the circular truncated cone hole (9) of the threaded hole to form a radial seal.
3. The sealing structure of the threaded hole in the environment of low-temperature and high-pressure liquefied gas according to claim 1, wherein the included angle between the generatrix of the circular truncated cone hole (9) and the axis thereof is b; and the value range of b is 30-60 degrees;
the included angle between the generatrix of the circular table section (8) and the axis thereof is a, the value range of a is 30-60 degrees, and the difference between a and b is not more than 1 degree.
4. The sealing structure of the threaded hole in the low-temperature and high-pressure liquefied gas environment according to claim 2, wherein the first O-ring (1) and the second O-ring (2) are made of fluororubber.
5. The sealing structure for the threaded hole in the low-temperature and high-pressure liquefied gas environment according to claim 1, wherein the thickness of the gasket is 2-3 mm, and the thickness error is not more than 0.1 mm.
6. The sealing structure for threaded holes in a cryogenic, high-pressure liquefied gas environment according to claim 1, wherein said gasket is made of teflon.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202120083813.7U CN214698708U (en) | 2021-01-13 | 2021-01-13 | Seal structure of screw hole under low temperature, high pressure liquefied gas environment |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202120083813.7U CN214698708U (en) | 2021-01-13 | 2021-01-13 | Seal structure of screw hole under low temperature, high pressure liquefied gas environment |
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| CN214698708U true CN214698708U (en) | 2021-11-12 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112709744A (en) * | 2021-01-13 | 2021-04-27 | 北京航天试验技术研究所 | Seal structure of screw hole under low temperature, high pressure liquefied gas environment |
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2021
- 2021-01-13 CN CN202120083813.7U patent/CN214698708U/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112709744A (en) * | 2021-01-13 | 2021-04-27 | 北京航天试验技术研究所 | Seal structure of screw hole under low temperature, high pressure liquefied gas environment |
| CN112709744B (en) * | 2021-01-13 | 2024-06-11 | 北京航天试验技术研究所 | Sealing structure of threaded hole under low-temperature and high-pressure liquefied gas environment |
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