Expanded polytetrafluoroethylene clamping and wrapping tooth-shaped pad

Abstract

The utility model discloses an expanded polytetrafluoroethylene clamping and wrapping tooth-shaped gasket which comprises a main sealing ring and further comprises an auxiliary sealing ring and an outer reinforcing ring. The auxiliary sealing ring coaxially sleeves the inner side of the main sealing ring; and the outer reinforcing ring coaxially sleeves the outer side of the main sealing ring. The internal main body of the main sealing ring is a metal tooth-shaped framework, and the cross section of the end face is tooth-shaped. The outer side end of the metal tooth-shaped framework is covered with an elastic polytetrafluoroethylene pad. The inner side wall of the main sealing ring is provided with a main sealing ring inner convex rib which is convex inwards, and the outer side wall of the auxiliary sealing ring is provided with an auxiliary sealing ring matching groove which is concave inwards; and the main sealing ring inner convex rib is matched and clamped with the auxiliary sealing ring matching groove. And a gap is formed between the matching of the inner convex rib of the main sealing ring and the matching groove of the auxiliary sealing ring in the axial direction. A concave main sealing ring outer groove is formed in the outer side wall of the main sealing ring, and the inner side of the outer reinforcing ring is connected with the main sealing ring outer groove in a matched and clamped mode. The scheme has the beneficial effects that the inner ring and the outer ring are additionally arranged on the inner ring and the outer ring of the main sealing ring respectively, so that the low-dissipation sealing requirement is met.

Description

Technical Field

[0001] The utility model relates to the field of sealing, in particular to an expanded polytetrafluoroethylene sandwiched toothed pad. Background Art

[0002] With the rapid development of modern industry and the strengthening and standardization of environmental regulations worldwide, there is a need for more stable, widely applicable, and pollution-free sealing products to meet more complex and demanding operating conditions. Toothed gaskets, also known as toothed gaskets or toothed sealing rings, are seals typically used in high-temperature and high-pressure applications. Conventional toothed gaskets are typically composed of a composite of a metal toothed skeleton and a non-metallic filler. The upper and lower surfaces of the metal skeleton are provided with concentric 90° serrated grooves, forming a metal skeleton layer with good deformation capacity. A layer of elastic polytetrafluoroethylene gasket of appropriate thickness is also laminated above and below the metal skeleton layer. For example, Chinese patent document CN103644297A, published on March 19, 2014, discloses a "metal skeleton toothed composite gasket with special-shaped teeth." The upper and lower end surfaces of the metal skeleton have multiple concentrically distributed radial circles of special-shaped teeth that curve toward the pressure source and are covered with a non-metallic sealing material. Compared with traditional sealing teeth, crescent-shaped or bow-shaped special-shaped teeth provide two additional rebound points and additional flexibility, avoiding stress concentration at the two inflection points of the upper part and the root of the tooth, having higher anti-yield and anti-fatigue properties, and increasing the service life of the gasket. The semicircular tooth top design of the present invention does not damage the flange even when it is subjected to torsional deformation under pressure. The present invention designs a pressure-stop boss between the special-shaped teeth to prevent the special-shaped teeth from being crushed and damaged due to excessive pre-tightening force, thereby ensuring the safety of the seal. However, the sealing surface of this type of tooth-shaped gasket is only the two end faces of the sealing ring, and the sealing effect is difficult to meet the low-emission sealing requirements. Summary of the Invention

[0003] Based on the above problems, the utility model provides an expanded polytetrafluoroethylene sandwich toothed gasket, which adds an inner ring and an outer ring to the inner ring and outer ring of the main sealing ring respectively, meeting the low-emission sealing requirements.

[0004] All parts in this solution are coaxially installed. Unless otherwise specified, the definitions of axial, radial and circumferential directions apply to all parts.

[0005] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions: an expanded polytetrafluoroethylene toothed gasket, comprising a main sealing ring,

[0006] Also includes a secondary sealing ring and an outer reinforcement ring;

[0007] The auxiliary sealing ring is coaxially sleeved on the inner side of the main sealing ring;

[0008] The outer reinforcement ring is coaxially sleeved on the outer side of the main sealing ring.

[0009] Preferably, the inner body of the main sealing ring is a metal tooth-shaped skeleton, and the cross-sectional shape of the end face is tooth-shaped.

[0010] Preferably, the outer side end of the metal tooth-shaped skeleton is covered with an elastic Teflon pad.

[0011] Preferably, the inner side wall of the main sealing ring is provided with a main sealing ring inner convex rib, and the outer side wall of the secondary sealing ring is provided with a secondary sealing ring matching groove; the main sealing ring inner convex rib and the secondary sealing ring matching groove are adaptively connected.

[0012] Preferably, the main sealing ring inner convex rib and the secondary sealing ring matching groove have a gap in the axial direction.

[0013] Preferably, the outer side wall of the main sealing ring is provided with a main sealing ring outer concave groove, and the inner side of the outer reinforcing ring is adaptively connected with the main sealing ring outer concave groove.

[0014] Preferably, the inner side of the outer reinforcing ring and the main sealing ring outer concave groove have a gap in the axial direction.

[0015] Preferably, the inner side of the outer reinforcing ring and the main sealing ring outer concave groove have a gap in the radial direction.

[0016] Preferably, the secondary sealing ring and the main sealing ring coincide in the thickness direction.

[0017] Preferably, the thicknesses of the secondary sealing ring, the main sealing ring and the outer reinforcing ring decrease in turn.

[0018] Preferably, the outer reinforcing ring is provided with a positioning structure.

[0019] The beneficial effects of the scheme are that the inner ring and the outer ring are respectively added to the inner ring and the outer ring of the main sealing ring, and the low-leakage sealing requirement is met. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 is an axial sectional view of the utility model;

[0021] Figure 2 is Figure 1 is an enlarged view of A part of the utility model;

[0022] Figure 3 is a structure schematic view of embodiment 7;

[0023] Figure 4 is a production technological process flow chart of the utility model.

[0024] Among them: 1 main sealing ring, 11 metal tooth-shaped skeleton, 12 elastic Teflon pad, 13 main sealing ring inner convex rib, 14 main sealing ring outer concave groove, 2 secondary sealing ring, 21 secondary sealing ring matching groove, 3 outer reinforcing ring, 31 outer reinforcing ring positioning hole. DETAILED DESCRIPTION

[0025] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0026] All parts in this solution are coaxially installed. Unless otherwise specified, the definitions of axial, radial and circumferential directions apply to all parts.

[0027] Example 1

[0028] Example 1 is an expanded polytetrafluoroethylene toothed pad. Figure 1 As shown, the expanded PTFE-encased toothed gasket in this example comprises a primary sealing ring 1, a secondary sealing ring 2, and an outer reinforcement ring 3. These three rings are concentric, and their thickness bisectors coincide. The primary sealing ring 1 is in the center, with the secondary sealing ring 2 located inside and the outer reinforcement ring 3 located outside.

[0029] The main body of the primary sealing ring 1 is a stainless steel, metal toothed frame 11, with the upper and lower end surfaces designed in a concentric, corrugated tooth profile. The secondary sealing ring 2, made of elastic polytetrafluoroethylene, is attached to the inner side of the primary sealing ring 1 via a snap-fit ​​mechanism. In this example, the secondary sealing ring 2 is 6 mm thick. The outer reinforcement ring 3, made of stainless steel, is attached to the outer side of the primary sealing ring 1 via a snap-fit ​​mechanism, but other materials can be used depending on design requirements.

[0030] The addition of the secondary sealing ring 2 allows the primary and secondary sealing rings 1 and 2 to work synchronously under low preload, significantly improving the sealing effect. The addition of the outer reinforcement ring 3 improves the positioning of the entire toothed pad and helps the primary and secondary sealing rings 1 and 2 better adapt to the sealing area, further improving the sealing effect.

[0031] Example 2

[0032] Example 2 is another expanded PTFE-encased toothed gasket, an improvement on Example 1. Specifically, the main sealing ring 1 comprises an inner and outer layer, with a metal toothed skeleton 11 serving as the inner layer. The upper and lower end surfaces of the metal toothed skeleton 11 are covered with elastic PTFE gaskets 12. In this example, the thickness of the elastic PTFE gasket 12 covering each end surface is 0.5 mm, resulting in a total thickness of 4 mm for the main sealing ring 1.

[0033] The rest is the same as Example 1.

[0034] Example 3

[0035] Example 3 is another expanded PTFE-wrapped toothed pad, which provides a specific combination structure of the main sealing ring 1 and the auxiliary sealing ring 2. Figure 2As shown, the inner side wall of the primary sealing ring 1 is provided with a primary sealing ring inner protruding rib 13 protruding inwardly, and the outer side wall of the secondary sealing ring 2 is correspondingly provided with a secondary sealing ring matching groove 21 recessed inwardly, the primary sealing ring inner protruding rib 13 is adapted to be clamped in the secondary sealing ring matching groove 21, thereby coaxially combining the primary sealing ring 1 and the secondary sealing ring 2 together, at this time the primary sealing ring 1 and the secondary sealing ring 2 can rotate relative to each other in the circumferential direction, thereby improving the adaptability.

[0036] The rest is the same as embodiment 2.

[0037] Embodiment 4

[0038] Embodiment 4 is another inflatable four-fluorine sandwiched tooth-shaped gasket. In this example, the width of the secondary sealing ring matching groove 21 is slightly larger than the thickness of the primary sealing ring inner protruding rib 13, and there is still a certain gap after assembly, so that the primary sealing ring 1 and the secondary sealing ring 2 can also move a small amount in the axial direction. The purpose of this gap is to reserve the compression deformation amount. When the inflatable four-fluorine sandwiched tooth-shaped gasket is compressed as a whole, since the thickness of the secondary sealing ring 2 is greater than that of the primary sealing ring 1, the thickness of the secondary sealing ring 2 will be compressed first to the initial thickness of the primary sealing ring 1, at this time the aforementioned reserved gap also disappears in the process of compression deformation, thereafter the secondary sealing ring 2 and the primary sealing ring 1 are synchronously compressed and the thickness is reduced, the compression deformation will be more uniform, which helps to improve the effect of low leakage sealing. The size of the gap here is estimated by a person skilled in the art according to the compression deformation amount of the secondary sealing ring 2 in actual application, or is preset according to experience.

[0039] The rest is the same as embodiment 3.

[0040] Embodiment 5

[0041] Embodiment 5 is another inflatable four-fluorine sandwiched tooth-shaped gasket, which provides a specific combination structure of the primary sealing ring 1 and the outer reinforcing ring 3. As shown, Figure 2 the outer side wall of the primary sealing ring 1 is provided with a primary sealing ring outer recess 14 recessed inwardly, and the inner side of the outer reinforcing ring 3 is adapted to be clamped with the primary sealing ring outer recess 14. At this time, the primary sealing ring 1 and the outer reinforcing ring 3 can rotate relative to each other in the circumferential direction, thereby improving the adaptability.

[0042] The rest is the same as embodiment 4.

[0043] Embodiment 6

[0044] Embodiment 6 is another inflatable four-fluorine sandwiched tooth-shaped gasket.

[0045] As shown, Figure 1 the inflatable four-fluorine sandwiched tooth-shaped gasket of this example includes a primary sealing ring 1, a secondary sealing ring 2 and an outer reinforcing ring 3, which are concentric rings, and the center lines of the thickness directions of the three are coincident. Among them, the primary sealing ring 1 is in the middle, the inner side of the primary sealing ring 1 is the secondary sealing ring 2, and the outer side of the primary sealing ring 1 is the outer reinforcing ring 3.

[0046] The main sealing ring 1 body part is a metal tooth-shaped skeleton 11 made of stainless steel, and the upper and lower end faces are designed as concentric corrugated tooth shapes in cross section. The secondary sealing ring 2 is arranged on the inner side of the main sealing ring 1 through a clamping structure, and is made of elastic fluorine. In this example, the thickness of the secondary sealing ring 2 is 6 mm. The outer reinforcing ring 3 is arranged on the outer side of the main sealing ring 1 through a clamping structure, and the material of the outer reinforcing ring 3 is stainless steel.

[0047] The main sealing ring 1 includes two layers, the metal tooth-shaped skeleton 11 is the inner layer, and the outer side of the upper and lower end faces of the metal tooth-shaped skeleton 11 is covered with an elastic fluorine pad 12. In this example, the thickness of the elastic fluorine pad 12 covered on each end face is 0.5 mm, and the thickness of the entire main sealing ring 1 is 4 mm.

[0048] As shown in Figure 2 , the inner side wall of the main sealing ring 1 is provided with a main sealing ring inner protruding rib 13 protruding inward, and the outer side wall of the secondary sealing ring 2 is correspondingly provided with a secondary sealing ring matching groove 21 recessed inward, and the main sealing ring inner protruding rib 13 is clamped in the secondary sealing ring matching groove 21, so that the main sealing ring 1 and the secondary sealing ring 2 are coaxially combined together.

[0049] The width of the secondary sealing ring matching groove 21 is slightly larger than the thickness of the main sealing ring inner protruding rib 13, and there is still a certain gap after assembly, so that the main sealing ring 1 and the secondary sealing ring 2 can also move a small amount in the axial direction.

[0050] As shown in Figure 2 , the outer side wall of the main sealing ring 1 is provided with a main sealing ring outer recess 14 recessed inward, and the inner side of the outer reinforcing ring 3 is clamped and connected with the main sealing ring outer recess 14.

[0051] The width of the main sealing ring outer recess 14 is slightly larger than the thickness of the outer reinforcing ring 3, and the diameter of the circle where the bottom of the main sealing ring outer recess 14 is located is also slightly smaller than the diameter of the inner circle of the outer reinforcing ring 3. Such design makes the main sealing ring 1 and the outer reinforcing ring 3 have a certain gap in the radial direction after assembly, so that the main sealing ring 1 and the outer reinforcing ring 3 can move a small amount in the axial direction and the radial direction.

[0052] The main function of the outer reinforcing ring 3 is to position the entire tooth-shaped pad. In this example, the outer reinforcing ring 3 is circular. When the tooth-shaped pad of this example needs to be installed at the flange end, the outer circle of the outer reinforcing ring 3 and the virtual circle surrounded by the bolt holes on the flange correspond in size, and after installation, the outer reinforcing ring 3 can be clamped in this virtual circle. At the same time, the main sealing ring 1 has a slight movement space relative to the outer reinforcing ring 3, which can better accurately align the sealing surface.

[0053] In this example, the thicknesses of the secondary sealing ring 2, the main sealing ring 1 and the outer reinforcing ring 3 are 6 mm, 4 mm and 1 mm respectively, and decrease in turn.

[0054] Example 7

[0055] Example 2 is another kind of bulking four-fluorine sandwiched tooth-shaped gasket. In this embodiment, positioning structure is provided on the outer reinforcing ring 3. Referring to Figure 3 shown, the outer reinforcing ring 3 of this example is a square with chamfered corners. There is an outer reinforcing ring positioning hole 31 on each corner of the square outer reinforcing ring 3, which is used as a bolt hole corresponding to the flange bolt, thereby fixing the outer reinforcing ring 3 on the flange. Those skilled in the art can also design different positioning structures according to different structures and different conditions of the sealing position.

[0056] The rest is the same as Example 5.

[0057] The production process flow of Example 6 is described below. Referring to Figure 4 shown, the production process flow of the bulking four-fluorine sandwiched tooth-shaped gasket of this embodiment includes the following steps in sequence:

[0058] 1. Metal skeleton inner ring processing;

[0059] 2. Metal skeleton tooth shape processing;

[0060] 3. Metal skeleton outer ring groove processing;

[0061] 4. Installing the movable outer ring into the metal skeleton groove;

[0062] 5. Making a steel stamp on the outer ring;

[0063] 6. Making a color mark on the outer ring;

[0064] 7. Cutting the upper and lower four-fluorine elastic pads;

[0065] 8. Covering the elastic four-fluorine pad to the metal tooth shape;

[0066] 9. Processing the inner lining elastic four-fluorine ring;

[0067] 10. Installing the inner lining elastic four-fluorine ring to the metal skeleton inner ring;

[0068] 11. Inspection and storage;

[0069] 12. Packaging and delivery.

[0070] The details are as follows:

[0071] Metal skeleton inner ring processing; that is, selecting a suitable type of metal, in this example 304 stainless steel, to make a ring;

[0072] Metal skeleton tooth shape processing; that is, pressing the aforementioned metal ring into a concentric corrugated tooth shape;

[0073] Metal skeleton outer ring groove processing; that is, the sealing ring inner convex rib 13 is turned on the inner side of the metal skeleton to be assembled with the auxiliary sealing ring 2; the outer groove 14 of the main sealing ring is turned on the outer side of the metal skeleton to be assembled with the outer reinforcing ring 3; at this time, the metal tooth-shaped skeleton 11 is processed;

[0074] The movable outer ring is installed into the metal skeleton groove; that is, the outer reinforcing ring 3, which is processed separately, is sleeved in the outer groove 14 of the main sealing ring; the material of the outer reinforcing ring 3 in this example is 304 stainless steel, and the thickness is 1 mm;

[0075] Steel stamping and color marking on the outer ring: according to the needs of customers, the outer reinforcing ring 3 is marked and colored, and necessary marking operations are performed for management and use;

[0076] Upper and lower Teflon elastic pad blanking: Teflon material is prepared for covering the two end faces of the metal tooth-shaped skeleton 11;

[0077] Covering the elastic Teflon pad to the metal tooth-shaped skeleton: using the Teflon material prepared just now, the elastic Teflon pad 12 is covered on the two end faces of the metal tooth-shaped skeleton 11 according to the design needs; at this time, the main sealing ring 1 is completed; the total thickness of the main sealing ring 1 including the inner metal tooth-shaped skeleton 11 and the elastic Teflon pad 12 on the upper and lower two end faces is 4 mm;

[0078] Processing the inner lining elastic Teflon ring: the auxiliary sealing ring 2 is prepared by Teflon material; the thickness of the elastic Teflon pad 12 in this example is 6 mm;

[0079] Installing the inner lining elastic Teflon ring to the metal skeleton inner ring: the assembly of the auxiliary sealing ring 2 and the main sealing ring 1 is completed.

[0080] The main technical indicators of the expanded Teflon clamping tooth-shaped pad in this example are as follows:

[0081] Serial number Item Unit Index value 1 Compression rate % 35±10 2 Rebound rate % ≥15 3 Leakage cm 3 / s]]> ≤ 1.0 x 10 -5 ]]

[0082] In summary, the technical advantages of the expanded Teflon clamping tooth-shaped pad in this example are:

[0083] 1. The expanded Teflon clamping tooth-shaped pad fills the material on the main sealing ring 1 of the metal tooth-shaped skeleton 11 with an elastic Teflon pad 12 with a thickness of 0.5 mm, and selects an elastic Teflon ring with a thickness of 6 mm for the auxiliary sealing ring 2 at the inner ring of the metal tooth-shaped skeleton 11, and a reinforced outer reinforcing ring 3 is combined with the outer ring of the main sealing ring 1.

[0084] 2、In the inner ring of the main sealing ring 1, the elastic four fluorine ring of the secondary sealing ring 2 is installed, so that the effective sealing surface area of the gasket is increased, in order to ensure the compression performance of the gasket under the standard flange bolt, the sealing material is selected and optimized, on the basis of ensuring the total thickness of the main sealing ring 1 is 4mm, the gasket thickness of the secondary sealing ring 2 is increased to 6mm, the low pre-tightening force technology that the compression thickness of the main sealing ring and the secondary sealing ring 2 is equal under the bolt pre-tightening force of 45MPa is realized, under the condition of ensuring the excellent compression performance of the gasket, the main sealing ring and the secondary sealing ring can simultaneously play the sealing role.

[0085] 3、In order to ensure the compression, resilience and sealing performance index of the gasket, the above performance index of the gasket will also change obviously with the change of the process parameters in the actual production process, so it is necessary to test the gasket production size control precision requirement and the selection of gasket thickness, therefore the improvement is carried out on the sealing surface of the metal tooth-shaped skeleton 11, the secondary sealing ring 2 is increased, and the stability of the compression resilience and other performances of the gasket is ensured.

[0086] Through scientific design and careful production, through the combination of different materials and the design of production process, finally the example of the four fluorine tooth-shaped gasket with expansion body can ensure excellent compression resilience and sealing performance, so as to meet the more complex, more demanding and long-term use working conditions, and can be widely used in equipment and various pipe flanges, container flanges, valves, heat exchanger interface parts in petroleum, chemical, metallurgy and electric power industries.

Claims

1. An expanded polytetrafluoroethylene (PTFE) toothed gasket comprising a main sealing ring (1), characterized in that: It also includes a secondary sealing ring (2) and an outer reinforcement ring (3); The auxiliary sealing ring (2) is coaxially sleeved on the inner side of the main sealing ring (1); The outer reinforcement ring (3) is coaxially sleeved on the outside of the main sealing ring (1); The inner body of the main sealing ring (1) is a metal tooth-shaped skeleton (11), and the cross-sectional shape of the end face is a tooth shape; The outer end of the metal toothed frame (11) is covered with an elastic polytetrafluoroethylene pad (12).

2. The expanded polytetrafluoroethylene (PTFE) toothed pad according to claim 1, characterized in that: The inner side wall of the main sealing ring (1) is provided with an inwardly convex main sealing ring inner rib (13), and the outer side wall of the auxiliary sealing ring (2) is provided with an inwardly concave auxiliary sealing ring matching groove (21); the main sealing ring inner rib (13) and the auxiliary sealing ring matching groove (21) are adapted to be snap-fitted.

3. The expanded polytetrafluoroethylene-enclosed toothed pad according to claim 2, characterized in that: There is a gap in the axial direction between the inner rib (13) of the primary sealing ring and the matching groove (21) of the secondary sealing ring.

4. The expanded polytetrafluoroethylene-enclosed toothed pad according to claim 1 or 2, characterized in that: An outer side wall of the main sealing ring (1) is provided with an inwardly concave main sealing ring outer groove (14), and the inner side of the outer reinforcement ring (3) is adapted and snap-fitted with the main sealing ring outer groove (14).

5. The expanded polytetrafluoroethylene-enclosed toothed pad according to claim 4, characterized in that: There is a gap in the axial direction between the inner side of the outer reinforcement ring (3) and the outer groove (14) of the main sealing ring.

6. The expanded polytetrafluoroethylene-enclosed toothed pad according to claim 4, characterized in that: There is a gap in the radial direction between the inner side of the outer reinforcement ring (3) and the outer groove (14) of the main sealing ring.

7. The expanded polytetrafluoroethylene-enclosed toothed pad according to claim 1 or 2, characterized in that: The secondary sealing ring (2) and the primary sealing ring (1) have bisectors in the thickness direction that coincide with each other.

8. The expanded polytetrafluoroethylene-enclosed toothed pad according to claim 1 or 2, characterized in that: A positioning structure is provided on the outer reinforcement ring (3).

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