CN212055831U - Creep-resistant polytetrafluoroethylene gasket - Google Patents

Abstract

The utility model provides a creep-resistant polytetrafluoroethylene gasket, includes annular polytetrafluoroethylene gasket body and metal location fixing device, metal location fixing device respectively with the medial surface and the lateral surface butt of annular polytetrafluoroethylene gasket body. The utility model discloses an anti creep polytetrafluoroethylene gasket adopts the metal to bordure and replaces former modified tetrafluoro gasket, has only structurally changed to the gasket, has cancelled the change that former adoption chemical synthesis mode, consequently efficient, with low costs, and pollution-free, this kind of seal gasket simple structure, and it is convenient to make.

Description

Creep-resistant polytetrafluoroethylene gasket

Technical Field

The utility model relates to a sealed field, concretely relates to creep-resistant polytetrafluoroethylene gasket.

Background

The sealing gasket has the advantages that the demand of the market for sealing high-temperature and low-temperature gaskets, particularly for sealing in a corrosion-resistant and oil-resistant environment is continuously increased, conventional sealing elements such as rubber and graphite sealing cannot be applied to sealing under special working conditions, and meanwhile, the rubber has the defects of easiness in aging, low temperature resistance and the like, the design and application of the sealing structure under certain special working conditions are severely restricted, even the development of the industry is restricted, and in order to solve the sealing problem under the special working conditions, a corrosion-resistant, aging-resistant and creep-resistant sealing gasket is urgently needed.

Polytetrafluoroethylene (abbreviated as PTFE in english), which is called "plastic king" by people, is a high molecular compound obtained by polymerizing tetrafluoroethylene, and has the characteristics of excellent chemical stability, corrosion resistance, sealing property, special electrical property, surface property, non-adhesiveness, self-lubricating property, low friction coefficient and the like.

Because of the unique performance characteristics, polytetrafluoroethylene is widely applied to sealing in the aerospace industry, the nuclear power system industry and the petrochemical industry, but the defects of poor resilience, easy creep deformation and the like of a sealing gasket made of the material limit the use of the sealing gasket, so that the service life and the application prospect are greatly reduced.

However, the creep resistance of the gasket directly determines whether the gasket can play a sealing role in the use of the gasket, and the creep refers to the phenomenon that the material deformation gradually extends along with the time lapse under constant temperature and constant pressure, for example, once the creep of the sealing gasket occurs, the compressive stress acting on the surface of the gasket is gradually reduced due to the extension deformation of the material, so that the sealing of the gasket is realized. As shown in FIGS. 1 and 2, after creep of the prior art PTFE gasket, d₄＞d₂，d₃＜d₁A concrete example of the object pair is shown in fig. 3.

At present, the creep-resistant mode of the polytetrafluoroethylene gasket is generally modified by adopting a material, mainly a composite mode of modifying polytetrafluoroethylene or adding rubber, high polymer materials and the like, but when the polytetrafluoroethylene is modified or added with other non-metal materials, the original corrosion resistance, temperature resistance and aging resistance of the polytetrafluoroethylene are greatly reduced. For example, CN201210237383.5, entitled formulation of filled modified polytetrafluoroethylene high thermal conductivity composite material and obtaining method thereof, provides a method for filling modified polytetrafluoroethylene, wherein graphite and carbon fiber material are filled in polytetrafluoroethylene, the volume fraction of graphite filling is 18 plus or minus 0.5%, and the volume fraction of carbon fiber filling is 10%; thus improving the mechanical property of the composite material, but the characteristics of the improved polytetrafluoroethylene are influenced by the filling material, so that the weather resistance and the acid and alkali resistance of the composite material are reduced. For example, CN1610452784.0 discloses a polytetrafluoroethylene/barium sulfate composite material and a preparation method thereof, wherein steel fibers and carbon fibers are used to improve the tensile strength, friction property and creep resistance of polytetrafluoroethylene, and fine fillers such as SiO2 and Al powder are sintered on the surface of polytetrafluoroethylene by an improved melting method, so as to improve the surface sintering state of polytetrafluoroethylene and significantly improve the bonding strength. However, this approach was made and found to result in black cores within the composite material, which resulted in an overall structural strength that was compromised.

If the rubber material is added into the modified polytetrafluoroethylene prepared by the method, the prepared product is influenced by the performance of the rubber, and has low temperature resistance and easy aging; if graphite is added, the acid resistance, alkali resistance, and weather resistance are lowered. In a word, the polytetrafluoroethylene material loses a plurality of excellent characteristics of the polytetrafluoroethylene after being modified, and the properties of the modified material are compatible with the properties of the filling material. Although the compression performance, the resilience performance and the creep resistance performance of the filled polytetrafluoroethylene are improved, the acid resistance, the weather resistance, the difficult aging of the material and other characteristics of the polytetrafluoroethylene are lost, so that the use of the polytetrafluoroethylene in the sealing field is greatly reduced.

Disclosure of Invention

The technical solution problem of the utility model is that: overcomes the defects of the prior art and provides a creep-resistant polytetrafluoroethylene gasket.

The technical solution of the utility model is that: the utility model provides a creep-resistant polytetrafluoroethylene gasket, includes annular polytetrafluoroethylene gasket body and metal location fixing device, metal location fixing device respectively with the medial surface and the lateral surface butt of annular polytetrafluoroethylene gasket body.

Further, the metal positioning and fixing device is a metal positioning ring.

Further, the metal positioning and fixing device comprises an inner metal wrapping edge and an outer metal wrapping edge, the inner metal wrapping edge is abutted to the inner side face of the annular polytetrafluoroethylene gasket body, and the outer metal wrapping edge is abutted to the outer side face of the annular polytetrafluoroethylene gasket body.

Further, the inner metal wrapping edge and/or the outer metal wrapping edge are/is a stainless steel band.

Further, the thickness of the inner stainless steel band is 0.2-0.3 mm.

Further, the inner metal wrapping edge and/or the outer metal wrapping edge are/is a multi-layer wrapped stainless steel band.

Furthermore, the number of the wrapped stainless steel bands is 2-3.

Further, the multi-layer wrapped stainless steel bands are connected by spot welding.

Compared with the prior art, the utility model the advantage lie in:

(1) the utility model discloses an anti creep polytetrafluoroethylene gasket adopts the metal to bordure and replaces former modified tetrafluoro gasket, only structurally changes to the gasket, has cancelled the change that former adoption chemical synthesis mode, consequently efficient, with low costs, and pollution-free.

(2) The creep-resistant polytetrafluoroethylene gasket of the utility model has simple structure, convenient manufacture and can realize mass production.

Drawings

FIG. 1 is a dimensional schematic of a prior art polytetrafluoroethylene gasket prior to compression.

FIG. 2 is a schematic representation of the dimensions of a prior art PTFE gasket after compression.

Fig. 3 is a schematic structural diagram of a creep-resistant ptfe gasket according to a first embodiment of the present invention.

Fig. 4 is a schematic structural view of a creep-resistant ptfe gasket according to a second embodiment of the present invention.

Fig. 5 is a schematic diagram of a flange seal implemented using the creep-resistant ptfe gasket of the present invention.

The reference numbers: 10-a polytetrafluoroethylene gasket body, 20-a metal positioning and fixing device, 21-inner metal wrapping edges 21 and 22-outer metal wrapping edges 22 and 30-an upper flange and 40-a lower flange.

Detailed Description

In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", and the like, indicate the orientation or positional relationship indicated based on the drawings, and are only for convenience of description and simplicity of description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore, should not be construed as limiting the present invention. Furthermore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless otherwise specified.

In the description of the present invention, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood in specific cases to those skilled in the art.

The utility model provides a creep-resistant polytetrafluoroethylene gasket, includes annular polytetrafluoroethylene gasket body 10 and metal location fixing device, metal location fixing device respectively with the medial surface and the lateral surface butt of annular polytetrafluoroethylene gasket body 10.

In embodiment 1, as shown in fig. 3, the metal positioning and fixing device is a metal positioning ring 20, the metal positioning ring 20 is divided into a small-diameter positioning ring and a large-diameter positioning ring, the small-diameter positioning ring is disposed in the ring of the annular ptfe gasket body 10, the outer side surface of the small-diameter positioning ring abuts against the inner side surface of the ptfe gasket body 10, the large-diameter positioning ring is sleeved on the outer side of the annular ptfe gasket body 10, and the inner side surface of the large-diameter positioning ring abuts against the outer side surface of the ptfe gasket body 10.

Preferably, the thickness of the polytetrafluoroethylene gasket body is 2-5mm, and the diameter can be designed according to actual equipment.

In embodiment 2, as shown in fig. 4, the metal positioning and fixing device 20 includes an inner metal covering 21 and an outer metal covering 22, the inner metal covering 21 abuts against the inner side surface of the annular ptfe gasket body 10, and the outer metal covering 22 abuts against the outer side surface of the annular ptfe gasket body 10.

Preferably, the thickness of the polytetrafluoroethylene gasket body is 2-5mm, and the diameter can be designed according to actual equipment.

Preferably, the inner metal wrapping 21 and/or the outer metal wrapping 22 are stainless steel strips, and the stainless steel strips are formed by cold rolling and bending and are wrapped on the inner side and the outer side of the tetrafluoroethylene gasket body 10.

Preferably, the thickness of the inner stainless steel band is 0.2-0.3 mm.

Preferably, the inner metal edge 21 and/or the outer metal edge 22 are a multi-layer wrapped stainless steel band.

Preferably, the number of the wrapped stainless steel bands is 2-3.

Further preferably, after the polytetrafluoroethylene gasket body 10 is wrapped by the multiple layers of stainless steel bands, the multiple layers of wrapped stainless steel bands are connected in a spot welding manner.

The creep-resistant polytetrafluoroethylene gasket that this application provided can use in a large number between plane flange or convex flange, creep-resistant polytetrafluoroethylene gasket user state is as shown in fig. 5, creep-resistant polytetrafluoroethylene gasket is pressed from both sides between two flanges of upper flange 30 and lower flange 40, adopts the bolt to carry out the pretension, pretension in-process creep-resistant polytetrafluoroethylene gasket receives the effect of flange seal face pretension stress, creep-resistant polytetrafluoroethylene gasket is by the weigh down, owing to receive the constraint effect of inside and outside becket at this moment, creep-resistant polytetrafluoroethylene gasket is the attenuation in the thickness direction only, and the diameter does not change, and this kind of method has effectively reduced creep-resistant polytetrafluoroethylene gasket's creep performance.

Simultaneously in the flange compression process, the flange sealing face is at first contacted with the metal, like this polytetrafluoroethylene just as similar filling material by firmly sealed in the cavity of metal bordure or holding ring, polytetrafluoroethylene body material is direct not with the medium contact, has improved its resistant medium performance by a wide margin, simultaneously because the metal is bordured or the constraint effect of holding ring, resilience performance increases.

Because polytetrafluoroethylene generally use the temperature and should not exceed 200 ℃, but as resistant sea water corrosion, durability, polytetrafluoroethylene is the first choice of fire control system and sea water system in the nuclear power system again, so adopt the creep-resistant polytetrafluoroethylene gasket that this application provided to solve the difficult problem of above operating mode, the creep-resistant polytetrafluoroethylene gasket that this application provided, its mode of borduring isolated oxygen for the gasket possesses fire behavior, and the gasket is difficult for ageing and creep relaxation simultaneously.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an illustrative embodiment," "an example," "a specific example," or "some examples" or the like mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

While embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that: various changes, modifications, substitutions and alterations can be made to the embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims (8)

1. The creep-resistant polytetrafluoroethylene gasket is characterized by comprising an annular polytetrafluoroethylene gasket body and a metal positioning and fixing device, wherein the metal positioning and fixing device is respectively abutted against the inner side face and the outer side face of the annular polytetrafluoroethylene gasket body.

2. The creep-resistant polytetrafluoroethylene gasket of claim 1 wherein the metal locating fixture is a metal locating ring.

3. The creep-resistant ptfe gasket of claim 1 wherein the metal locating fixture comprises an inner metal border and an outer metal border, the inner metal border abutting an inner side of the annular ptfe gasket body and the outer metal border abutting an outer side of the annular ptfe gasket body.

4. The creep-resistant polytetrafluoroethylene gasket of claim 3, wherein the inner metal border and/or the outer metal border is a stainless steel strip.

5. The creep-resistant polytetrafluoroethylene gasket of claim 4, wherein the thickness of the inner stainless steel band is 0.2-0.3 mm.

6. A creep-resistant PTFE gasket according to claim 4 or 5, wherein the inner and/or outer metal rims are multi-layer wrapped stainless steel strips.

7. The creep-resistant polytetrafluoroethylene gasket of claim 6, wherein the number of layers of the wrapped stainless steel strip is 2-3.

8. The creep-resistant polytetrafluoroethylene gasket of claim 6 wherein the multi-layer wrapped stainless steel strips are joined by spot welding.

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