CN113217726B - Metal octagonal cushion and design method thereof - Google Patents
Metal octagonal cushion and design method thereof Download PDFInfo
- Publication number
- CN113217726B CN113217726B CN202110392878.4A CN202110392878A CN113217726B CN 113217726 B CN113217726 B CN 113217726B CN 202110392878 A CN202110392878 A CN 202110392878A CN 113217726 B CN113217726 B CN 113217726B
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- Prior art keywords
- octagonal
- ring
- height
- cushion
- pad
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
- F16L23/00—Flanged joints
- F16L23/16—Flanged joints characterised by the sealing means
- F16L23/18—Flanged joints characterised by the sealing means the sealing means being rings
- F16L23/20—Flanged joints characterised by the sealing means the sealing means being rings made exclusively of metal
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16J—PISTONS; CYLINDERS; SEALINGS
- F16J9/00—Piston-rings, e.g. non-metallic piston-rings, seats therefor; Ring sealings of similar construction
- F16J9/12—Details
- F16J9/20—Rings with special cross-section; Oil-scraping rings
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16J—PISTONS; CYLINDERS; SEALINGS
- F16J9/00—Piston-rings, e.g. non-metallic piston-rings, seats therefor; Ring sealings of similar construction
- F16J9/26—Piston-rings, e.g. non-metallic piston-rings, seats therefor; Ring sealings of similar construction characterised by the use of particular materials
Abstract
The invention belongs to the technical field of pressure pipelines and pressure containers, and particularly relates to a metal octagonal pad and a design method thereof. The technical scheme is as follows: a metal octagonal pad comprises an octagonal pad, wherein the height of a bevel edge of the octagonal pad is 1/n of the ring height of the octagonal pad, n is 3-4, and the H/A ratio of the ring height to the ring width of the octagonal pad is not more than 1.6. A design method of a metal octagonal cushion comprises the following steps: s1: limiting the height of the bevel edge of the octagonal pad to be 1/4-1/3 of the ring height of the octagonal pad, wherein the H/A ratio of the ring height to the ring width of the octagonal pad is not more than 1.6; s2: initially determining the ring width of the octagonal cushion; checking the compressive stress generated by the annular plane where the ring width of the octagonal cushion is located by using the maximum bolt installation load which possibly occurs, and determining the ring width of the octagonal cushion if the compressive stress does not exceed the allowable compressive strength; s3: the ring height H is determined according to the ratio H/A of the ring height to the ring width of the octagonal pad. The invention provides a metal octagonal pad for simplifying a process of determining a ring width and a ring height and a design method thereof.
Description
Technical Field
The invention belongs to the technical field of pressure pipelines and pressure containers, and particularly relates to a metal octagonal pad and a design method thereof.
Background
The octagonal cushion has a radial self-tightening effect and is widely adopted in high-pressure grade flanges of CL900(PN150) and above. The size of the CLASS2500(PN420) grade high-pressure standard flange which can be adopted in China at present can be limited to 12 inches (DN300) and below according to American standard, and the design method of a sealing ring gasket-octagonal gasket which is mainly suffered from the grade flange can not be substantially broken through.
In order to break through the limitation of the current American standard, the design of a CLASS2500(PN420) grade high-pressure flange of 14 inches (DN350) and above is made in China, the high-pressure flange is standardized, the design and manufacturing cost of a pressure pipeline and a pressure container flange is reduced, the possibility is further provided for the large-scale of the device, and the design method of the octagonal cushion needs to be broken through.
Disclosure of Invention
In order to solve the above problems of the prior art, the present invention is directed to a metal octagonal pad and a design method thereof that simplify a process of determining a ring width and a ring height.
The technical scheme adopted by the invention is as follows:
a metal octagonal pad comprises an octagonal pad, wherein the height of the inclined edge of the octagonal pad is 1/n of the ring height of the octagonal pad, n is 3-4, and the H/A ratio of the ring height to the ring width of the octagonal pad is not more than 1.6; wherein H is the ring height and A is the ring width.
When n is 3-4 and H/A is less than or equal to 1.6, the design of the octagonal cushion can be greatly simplified to check that the compressive stress in the annular plane where the annular width A is located does not exceed a certain numerical value, so that the octagonal cushion does not generate plastic deformation in the height direction under the action of bolt load.
In a preferred embodiment of the present invention, the material of the octagonal pad is metal.
As a preferable scheme of the invention, the material of the octagonal cushion is carbon steel or stainless steel.
A design method of a metal octagonal cushion comprises the following steps:
s1: the height of the bevel edge of the octagonal pad is defined to be 1/4-1/3 of the ring height of the octagonal pad, and the H/A ratio of the ring height to the ring width of the octagonal pad is not more than 1.6;
s2: initially determining the ring width of the octagonal cushion; checking the compressive stress generated by the annular plane where the ring width of the octagonal cushion is located by using the possible maximum bolt mounting load, and determining the ring width of the octagonal cushion if the compressive stress does not exceed the allowable compressive strength;
s3: determining the ring height H according to the ratio H/A of the ring height to the ring width of the octagonal cushion;
wherein H is the ring height value and A is the ring width value.
The design method greatly simplifies the complex mechanics problem by limiting the ratio of the height of the bevel edge of the octagonal pad to the ring height to the ring width, does not need complex mechanics analysis and calculation, and lays a foundation for the development of detachable pipelines and pressure containers to high pressure and large size.
As a preferred scheme of the invention, the possible maximum bolt installation load is 50-70% of the bolt yield strength.
In a preferred embodiment of the present invention, the required compressive strength is set to 480 to 530 MPa.
In a preferred embodiment of the present invention, the required compressive strength is set to 510 MPa.
The invention has the beneficial effects that:
the height of the bevel edge of the octagonal pad is limited to 1/4-1/3 of the ring height of the octagonal pad, and the ratio H/A of the ring height to the ring width of the octagonal pad is not more than 1.6. And checking the compressive stress generated by the annular plane where the ring width of the octagonal cushion is located by using the maximum bolt installation load which possibly occurs, so as to determine whether the ring width of the octagonal cushion is properly selected or not, and ensure that the octagonal cushion does not generate plastic deformation in the height direction under the action of the bolt load. And determining the ring height H according to the ratio H/A of the ring height to the ring width of the octagonal pad. By the design method, the design method can be used. The design method greatly simplifies the complex mechanics problem by limiting the ratio of the height of the bevel edge of the octagonal pad to the ring height to the ring width, does not need complex mechanics analysis and calculation, and lays a foundation for the development of detachable pipelines and pressure containers to high pressure and large size.
Drawings
FIG. 1 is a schematic structural view of the present invention;
FIG. 2 is an assembly view and a bending moment view of the present invention.
In the figure, A-Ring Width value; c-ring plane width value; h-ring high value; p-internal pressure; f-the lateral component of the hypotenuse.
Detailed Description
Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are illustrative and intended to be illustrative of the invention and are not to be construed as limiting the invention.
As shown in FIGS. 1 and 2, the width of the octagonal cushion ring is set to be A, the width of the ring plane is set to be C, the ring height is set to be H, and the height of the bevel edge is set to be 1/n of the height of the octagonal cushion.
The ratio H/A of the ring height to the ring width is not more than 1.6.
According to the force analysis in the figure, the octagonal cushion ring is subjected to the greatest stress in unit length under the action of the internal pressure pThe large bending moment is:
the larger n is, the larger the maximum bending moment is, and when n is 4,
bending stress:
shear stress:
when H/a is 1.6, σ is 0.96p and τ is 0.8 p.
The shear allowable stress is 80% of the tensile allowable stress S, i.e., 0.8S, and the bending allowable stress is the tensile allowable stress S of the material. Since the design pressure of the piping system is much less than the tensile allowable stress (i.e., p < S). Therefore, the method comprises the following steps:
σ＝0.96p＜0.96S＜S；
τ＝0.8p＜0.8S。
therefore, when n is 3-4 and H/A is less than or equal to 1.6, no matter how large the design pressure is (the design pressure cannot exceed the allowable tensile stress of the material), the stress of the octagonal cushion meets the requirement, the octagonal cushion is safe, and the influence of the internal pressure of the pipeline system on the octagonal cushion is not required to be considered any more in the design of the octagonal cushion.
When n is 3-4 and H/A is less than or equal to 1.6, the design of the octagonal cushion can be greatly simplified to check that the compressive stress in the annular plane where the annular width A is located does not exceed a certain numerical value, so that the octagonal cushion does not generate plastic deformation in the height direction under the action of bolt load. As the compression strength of the common carbon steel and stainless steel metal materials is about 600-660 MPa, the allowable compression strength is 480-530 MPa according to the coefficient of multiplying the compression strength by 0.8. The allowable compressive strength recommended by the design method is 510 MPa.
The design method of the octagonal cushion comprises the following steps: the height of the bevel edge of the octagonal pad is defined to be 1/4-1/3 of the height of the octagonal pad, and the ratio H/A of the height of the ring to the width of the ring is not more than 1.6. And (3) checking the compressive stress generated by the annular plane where the width of the octagonal cushion ring is located by using the maximum bolt installation load (about 50-70% of bolt yield strength) which can occur, and ensuring that the compressive stress does not exceed 510MPa, thereby determining whether the width A of the octagonal cushion ring is selected properly. The loop height H is then determined at the appropriate H/A ratio (not exceeding 1.6).
The design method greatly simplifies the complex mechanics problem by limiting the ratio of the height of the bevel edge of the octagonal cushion and the ring height to the ring width, does not need complex mechanics analysis and calculation, lays a foundation for the development of detachable pipelines and pressure containers to high pressure and large size directions, has wide application prospect in high-pressure equipment and high-pressure pipelines such as hydrogenation reactors, ammonia synthesis towers and the like in the petrochemical industry, and inevitably promotes the design, manufacture and localization level of the equipment and pipeline flanges.
The invention is not limited to the above alternative embodiments, and any other various forms of products can be obtained by anyone in the light of the present invention, but any changes in shape or structure thereof, which fall within the scope of the present invention as defined in the claims, fall within the scope of the present invention.
Claims (7)
1. A metal octagonal cushion is characterized by comprising an octagonal cushion, wherein the height of a bevel edge of the octagonal cushion is 1/n of the ring height of the octagonal cushion, n is 3-4, and the ratio H/A of the ring height to the ring width of the octagonal cushion is not more than 1.6; wherein H is the ring height and A is the ring width.
2. The metal octagonal cushion according to claim 1, wherein the material of the octagonal cushion is metal.
3. The metal octagonal cushion according to claim 1, wherein the material of the octagonal cushion is carbon steel or stainless steel.
4. A design method of a metal octagonal cushion is characterized by comprising the following steps:
s1: the height of the bevel edge of the octagonal pad is defined to be 1/4-1/3 of the ring height of the octagonal pad, and the H/A ratio of the ring height to the ring width of the octagonal pad is not more than 1.6;
s2: initially determining the ring width of the octagonal cushion; checking the compressive stress generated by the annular plane where the ring width of the octagonal cushion is located by using the possible maximum bolt mounting load, and determining the ring width of the octagonal cushion if the compressive stress does not exceed the allowable compressive strength;
s3: determining the ring height H according to the ratio H/A of the ring height to the ring width of the octagonal cushion;
wherein H is the ring height value and A is the ring width value.
5. The method for designing a metal octagonal cushion according to claim 4, wherein the maximum bolt installation load that can occur is 50% -70% of the bolt yield strength.
6. The method as claimed in claim 4, wherein the allowable compressive strength is set to 480 to 530 MPa.
7. The method of claim 6, wherein the allowable compressive strength is set to 510 Mpa.
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| CN202110392878.4A CN113217726B (en) | 2021-04-13 | 2021-04-13 | Metal octagonal cushion and design method thereof |
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| CN202110392878.4A CN113217726B (en) | 2021-04-13 | 2021-04-13 | Metal octagonal cushion and design method thereof |
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| CN113217726A CN113217726A (en) | 2021-08-06 |
| CN113217726B true CN113217726B (en) | 2022-06-07 |
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Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1056343A (en) * | 1962-07-17 | 1967-01-25 | Wmf Wuerttemberg Metallwaren | Metal forming apparatus using high energy explosive pressures |
| DE3103551A1 (en) * | 1981-02-03 | 1982-08-12 | Kempchen & Co Gmbh, 4200 Oberhausen | Sealing arrangement for flange seals |
| CN201339784Y (en) * | 2008-12-26 | 2009-11-04 | 艾志(南京)环保垫片预紧材料有限公司 | Balance type cambered octagonal metallic sealing ring gasket |
| CN202349447U (en) * | 2011-11-25 | 2012-07-25 | 玉环县东海石化设备制造厂 | Self-sealing elastic metallic annular gasket |
| CN211599521U (en) * | 2019-11-25 | 2020-09-29 | 内蒙古伊泰化工有限责任公司 | Sealing flange and flexible graphite composite octagonal cushion thereof |
| CN212508729U (en) * | 2020-05-08 | 2021-02-09 | 中国成达工程有限公司 | Stress relieving structure of multistage compressor unit integrated design |
| CN212804697U (en) * | 2020-08-14 | 2021-03-26 | 温州正海密封件有限公司 | Octagonal metal annular gasket |
-
2021
- 2021-04-13 CN CN202110392878.4A patent/CN113217726B/en active Active
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1056343A (en) * | 1962-07-17 | 1967-01-25 | Wmf Wuerttemberg Metallwaren | Metal forming apparatus using high energy explosive pressures |
| DE3103551A1 (en) * | 1981-02-03 | 1982-08-12 | Kempchen & Co Gmbh, 4200 Oberhausen | Sealing arrangement for flange seals |
| CN201339784Y (en) * | 2008-12-26 | 2009-11-04 | 艾志(南京)环保垫片预紧材料有限公司 | Balance type cambered octagonal metallic sealing ring gasket |
| CN202349447U (en) * | 2011-11-25 | 2012-07-25 | 玉环县东海石化设备制造厂 | Self-sealing elastic metallic annular gasket |
| CN211599521U (en) * | 2019-11-25 | 2020-09-29 | 内蒙古伊泰化工有限责任公司 | Sealing flange and flexible graphite composite octagonal cushion thereof |
| CN212508729U (en) * | 2020-05-08 | 2021-02-09 | 中国成达工程有限公司 | Stress relieving structure of multistage compressor unit integrated design |
| CN212804697U (en) * | 2020-08-14 | 2021-03-26 | 温州正海密封件有限公司 | Octagonal metal annular gasket |
Non-Patent Citations (1)
| Title |
|---|
| 庞冠.管法兰螺栓安装应力的设计计算.《化工设计》.2020, * |
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| CN113217726A (en) | 2021-08-06 |
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