WO2017115400A1

WO2017115400A1 - Spiral wound gasket

Info

Publication number: WO2017115400A1
Application number: PCT/JP2015/086459
Authority: WO
Inventors: 聡中里; 真也黒河
Original assignee: 日本バルカー工業株式会社
Priority date: 2015-12-28
Filing date: 2015-12-28
Publication date: 2017-07-06
Also published as: CN108474476B; CN108474476A

Abstract

Provided is a spiral wound gasket which not only exhibits sealing properties, but also has a low risk of filler fracture, even after being used in a high-temperature atmosphere for a long period of time. This spiral wound gasket is provided with a gasket body formed by superposing a filler material and a hoop material and winding said materials into a spiralling shape. The spiral wound gasket is characterized in that: the filler material comprises a sheet including inorganic fibres, and when a rectangular parallelepiped test piece having dimensions of 30 mm (long sides)×15 mm (short sides), and a thickness of 0.5±0.05 mm is extracted from the filler material, heated at 500˚C for 96 hours, and subsequently placed on two rods separated by an interval of 14 mm such that the short sides are parallel with the rods and the centre of the test piece overlaps the centre of the interval, and a rectangular parallelepiped weight having a weight of 1 g, and dimensions of at least 9 mm (short sides)×15 mm (long sides), is placed on the centre of the test piece such that the central axes of the respective long sides of the test piece and the weight intersect, and the test piece can hold the weight for 5-10 seconds without breaking, the strength is deemed to be 1 g, and when the filler strength is defined as the weight of the weights that can be held by the test piece until just before the test piece breaks after repeatedly having 1 g weights further placed thereon and holding said weights for 5-10 seconds, the filler strength is at least 9 g.

Description

Spiral wound gasket

The present invention relates to a spiral wound gasket, and more particularly to a spiral wound gasket using inorganic fibers as a filler material of a gasket body.

A spiral wound gasket (SWG) used at high temperature and high pressure has a structure as shown in FIG. That is, in the spiral wound gasket, the filler material 1 and the hoop material 2 made of a thin metal tape having a V-shaped cross section are overlapped and wound in a spiral shape, and the winding start and end are wound. The gasket body 10 is formed by performing two or three rounds of idle winding with only 2 and fixing them by spot welding or the like.

The inner ring ring member 3 made of an annular metal plate is fixed to the inner peripheral edge of the gasket body 10 as a guide member by fitting it. Further, an outer ring member 4 made of an annular metal plate is fixed to the outer peripheral edge of the gasket body 10 as a guide member by fitting.

As such a filler material, typically, an expanded graphite sheet (for example, Patent Document 1: Japanese Patent Application Laid-Open No. 2011-144881) and a sheet mainly composed of mica (for example, Patent Document 2: Japanese Patent Application Laid-Open No. 2007-127178). ), Inorganic fibers (for example, Patent Document 3: JP-A-7-305772).

The sealability of these filler materials under the maximum use temperature and long-term heating conditions is outlined in the table below.

The expanded graphite sheet is difficult to use in a high temperature environment, and is oxidized and deteriorates when exposed to a high temperature, and the sheet mainly composed of mica has a problem that its use range is narrow and its versatility is poor.

A sheet containing inorganic fibers has an advantage of having a sealing property in a high region at a high temperature region up to 500 ° C. However, there is a problem that the sealing performance deteriorates when used for a long time at high temperature.

JP 2011-144881 A JP 2007-127178 A Japanese Patent Application Laid-Open No. 7-307772

Under such circumstances, the present invention has been made in view of the problems in the prior art as described above, and not only exhibits sealing properties even after use under a long-term high-temperature atmosphere, but also lacks filler defects. An object of the present invention is to provide a spiral wound gasket that has a low risk of occurrence.

In general, the following mechanism can be considered as a cause of a decrease in sealing performance of a spiral wound gasket.

(i) Contact leakage between gasket and flange (ii) Permeation leakage through the filler material (iii) Permeation leakage through the interface between the filler material and the hoop material In particular, vortex winding using a sheet containing inorganic fibers as the filler material In the case of a shaped gasket, it is considered that the sealability is lowered by (i) when used for a long time under heating conditions.

The reason for this is that the spiral wound gasket using “sheets containing inorganic fibers” as a filler material, when the surface pressure of the gasket is reduced by repeated long-term use and heating / cooling at high temperatures, The binder component disappears due to heat. And when a binder component lose | disappears, the intensity | strength of filler material itself falls and it becomes impossible to hold | maintain the shape as a filler material of a sealing surface. As a result, it is considered that the inorganic fiber or the like in the filler material falls off from the sealing surface due to pressure or vibration in the pipe, and a leak path is generated at the contact surface between the gasket and the flange, resulting in a decrease in sealing performance. Further, when the strength of the filler material is lowered, the dropped inorganic fibers are scattered, so there is a concern about the influence on the environment.

And the present inventors have further studied earnestly, by using a filler material whose filler strength after heating measured in a predetermined heating condition is in a specific range, such as pipe stress and internal pressure during use of the spiral wound gasket The present inventors have found that filler deficiency due to the action of external factors can be suppressed and have completed the present invention.

The configuration of the present invention is as follows.
[1] A spiral wound gasket including a gasket body formed by overlapping a filler material and a hoop material and winding them in a spiral shape,
The filler material comprises a sheet containing inorganic fibers,
A rectangular parallelepiped test piece having a length of 30 mm × short side of 15 mm and a thickness of 0.5 ± 0.05 mm is taken from the filler material, and the test piece is heated at 500 ° C. for 96 hours. Place on the two bars so that the short side is parallel to the bar and the center of the test piece overlaps the center of the interval, and the center of the test piece is 1 g in weight, and the dimensions are short side 9 Place a weight of a rectangular parallelepiped with a length of 15 mm or more on the long side so that the central axis of the long side of the test piece and the weight is perpendicular to each other, and the strength is 1 g when the test piece is not broken or held for 5 to 10 seconds. As described above, when a weight of 1 g is further applied and repeated holding for 5 to 10 seconds and the weight of the weight that can be held immediately before the test piece breaks is taken as the strength of the filler, the strength is 9 g or more. Spiral wound gasket.
[2] The composition of the filler material ranges from 74 to 85% by weight of inorganic filler, 2 to 20% by weight of inorganic fiber, 2 to 20% by weight of organic fiber, and 4 to 12% by weight of organic binder (the total is 100% by weight) %)). The spiral wound gasket according to [1].
[3] The spiral wound gasket according to [1] or [2], wherein rock wool is included as the inorganic fiber.
[4] The spiral wound gasket according to [3], wherein 75% by weight or more of the inorganic fiber is rock wool.
[5] The spiral wound gasket according to any one of [1] to [4], wherein the average fiber diameter of the inorganic fibers is in the range of 11 to 20 μm.
[6] The spiral wound gasket according to any one of [1] to [5], wherein the average aspect ratio of the inorganic fibers is in the range of 70 to 115.

Since the spiral wound gasket of the present invention uses a filler material having a high filler strength evaluated under predetermined conditions, it has a high sealing performance when used for a long time under high temperature conditions.

Specifically, after heating under predetermined conditions, a filler material having a certain strength or more is used. As a result, the loss of the filler material due to external factors such as internal pressure load is suppressed during high-temperature long-term use, and the fluid can be sealed for a long time even in a high-temperature environment.

It is a fragmentary sectional view which shows the outline of a spiral wound gasket. FIG. 2 is a schematic view of measuring the strength of the filler material.

Hereinafter, the spiral wound gasket of the present invention will be described in more detail.

The spiral wound gasket of the present invention includes an annular gasket body formed by overlapping a filler material and a hoop material and winding them in a spiral shape as shown in FIG.

[Filler material]
A filler material consists of a sheet | seat which mix | blended inorganic fiber.

In the present invention, with respect to the inorganic fibers blended in the filler material, fibers having a small fiber length (short) and a large fiber diameter (thick) are preferably used. That is, the fiber has a small aspect ratio. By using the inorganic fiber, it was considered that the inorganic fiber is not easily broken and normality is maintained, and the strength as a filler is increased.

As the inorganic fibers, inorganic fibers other than asbestos are used, and specific examples include ceramic fibers, rock wool, glass fibers, titanate fibers, and the like. Such inorganic fibers are desirably flexible and non-rigid, and the average fiber diameter is 20 μm or less, preferably 11 to 20 μm. The average aspect ratio is 150 or less, preferably 115 or less, and more preferably in the range of 70 to 115. The average fiber length is appropriately selected from the fiber diameter and aspect ratio described above.

When an inorganic fiber having an aspect ratio and a fiber diameter in this range is used, a predetermined filler strength is exhibited.

The shape of the inorganic fiber is obtained by measuring the fiber diameter and the fiber length by microscopic observation of 100 samples and calculating the average value and calculating the aspect ratio.

In the present invention, such inorganic fibers may be used alone or in combination of two or more.

In the present invention, it is preferable that rock wool is included as the inorganic fiber without adversely affecting the environment from the viewpoint of biodegradability. Furthermore, it is preferable that 75% by weight or more of the inorganic fiber is rock wool.

It is desirable that the filler material is formed including organic fibers, inorganic fillers, inorganic binders and organic binders together with the inorganic fibers.

Examples of organic fibers include natural fibers such as plant fibers, synthetic fibers such as aramid fibers, carbonized fibers, carbon fibers, and graphitized fibers. These organic fibers may be used alone or in combination of two or more.

These organic fibers play a role of increasing the strength of the filler material such that the filler material does not break when the spiral wound gasket is manufactured by winding the filler material and the hoop material. Such an organic fiber is desirably flexible and does not deteriorate the airtightness of the spiral wound gasket obtained, and the fiber diameter is preferably 10 μm or less and preferably 0.2 μm or more. Therefore, as such an organic fiber, it is desirable to use at least one kind of fibrillated pulp-like aramid fiber having a fiber diameter as described above.

Examples of inorganic fillers include talc, clay, calcium carbonate, barium sulfate, zinc oxide, titanium oxide, and silica. These inorganic fillers play a role in increasing the clogging (airtightness) between fibers, the flexibility of the filler, and the shape retention (aggregation) of the filler at high temperatures, and remain without disappearing even at high temperatures. And plays a role in maintaining the sealing performance. The particle size of such an inorganic filler is preferably fine, and specifically, it is desirable to have a particle size distribution in which the particle size is 5 μm or less and the particle size of 1 μm or less is 5% or more. In the present invention, it is desirable to use two or more kinds of fillers having different particle size distributions in combination, and when two or more kinds of fillers having different particle size distributions are used in combination as described above, A gasket having excellent flexibility can be obtained.

The binder combines the fiber and inorganic filler, plays a role in enhancing the sealing performance and giving the filler material mechanical strength, and can be either organic or inorganic, or a combination of organic and inorganic binders. Also good. Specific examples of such an inorganic binder include polyphosphate and water glass. Specific examples of organic binders include, for example, NBR-based, SBR-based, acrylic ester-based, fluorine-based rubber-based elastomer-based organic binders, methylsilicone-based binders, phenylsilicone-based binders, and other silicone-based binders. Or a binder of phenol such as a water-dispersed phenol resin.

In addition to the above-described components, the filler material may contain a water / oil repellent such as paraffin wax as necessary. When such a water / oil repellent is used, the sealing property at room temperature can be improved.

Further, in addition to the above components, the filler material of the present invention may further contain various vulcanizing agents, vulcanization accelerators, vulcanization aids, anti-aging agents, colorants and the like.

The filler material is in the range of 74 to 85% by weight of inorganic filler, 2 to 20% by weight of inorganic fiber, 2 to 20% by weight of organic fiber, and 4 to 12% by weight of organic binder (the total is 100% by weight). It is preferable in order to express the strength.

When the filler material used in the present invention contains the inorganic fiber and the inorganic filler as described above, and further an inorganic binder, the inorganic material is in a total amount of 76 to 94% by weight, preferably 85 to 90% by weight (however, When the inorganic binder is included, the total of the inorganic filler, the inorganic fiber, the organic fiber, the organic binder, and the inorganic binder is 100% by weight).

The inorganic fiber in the filler material is contained in an amount of 2 to 20% by weight, preferably 2 to 19% by weight, particularly preferably 2 to 18% by weight, and the inorganic fiber is contained in a total amount of 100 parts by weight of the above inorganic substances. It is desirable that it is contained in an amount of 1.8 parts by weight or more, preferably 3.5 parts by weight or more.

In the filler material, the total amount of the inorganic binder and the organic binder is 5 to 20% by weight, preferably 7 to 17% by weight, and the total amount of the inorganic fiber and the organic fiber is 4 to 20% by weight, preferably Is preferably contained in an amount of 5 to 15% by weight.

The organic fiber is desirably contained in the filler material in an amount of 2 to 20% by weight, preferably 2.0 to 13.7% by weight, and particularly preferably 2.0 to 9.7% by weight.

The filler material containing the inorganic material composed of the inorganic fiber, the inorganic binder, and the inorganic filler in the total amount as described above is excellent in airtightness at high temperature. Note that the filler material having an inorganic content of less than 76% by weight contains a large amount of organic matter, so that it is decomposed at a high temperature, the weight loss becomes significant, and the effect of sizing the binder is lost.

Further, as described above, the filler material containing the inorganic fiber and the organic fiber in a total amount of 3 to 20% by weight has the strength required when manufacturing the filler material and the strength required when manufacturing the spiral wound gasket. ing. Moreover, the spiral wound gasket having the filler material is excellent in sealing properties at room temperature, and does not impair airtightness even when used at high temperatures due to its heat loss.

The filler material can be produced by a conventionally known method such as a papermaking method. For example, the filler material can be produced by the papermaking method as follows. First, after a predetermined amount of organic fiber, inorganic fiber and inorganic filler are dispersed in water using a hydra pulper or a heater, a predetermined amount of organic / inorganic binder and, if necessary, a vulcanizing agent, a vulcanization accelerator, and a water repellent It was obtained after adding various auxiliary materials such as agents to adjust the slurry concentration as appropriate, then adding a fixing agent as necessary, and attaching the organic / inorganic binder to the fibrous material, inorganic filler, etc. The slurry is sequentially guided to a chest and then to a paper machine to obtain a filler material sheet. If necessary, by using a flocculant at the paper making stage, the slurry may be diluted to a concentration capable of making paper while maintaining the uniform dispersibility of the slurry.

The strength of the filler material used in the present invention evaluated below is 9 g or more, preferably 10 g or more, and more preferably 11 g or more. When a filler material having such strength is used, long-term sealing is possible under heating conditions. Since the strength of the filler material after heating is high, the loss of the filler can be suppressed, and long-term sealing can be achieved. The upper limit of the strength is not particularly limited as long as it can be processed.

In order to adjust to such filler strength, the fiber diameter, aspect ratio, fiber length, and content in the filler material of the inorganic fiber are important, and adjustment is possible by using the one in the predetermined range described above. It becomes.
A rectangular parallelepiped test piece having a length of 30 mm × short side of 15 mm and a thickness of 0.5 ± 0.05 mm is taken from the strength measurement filler material and heated at 500 ° C. in an air atmosphere for 96 hours. By heating, the binder and the organic fiber disappear. The test specimen after heating is placed on two round bars (made of stainless steel with a diameter of about 2.4 mm (2.4 to 2.6 mm)) with a spacing of 14 mm so that the rectangular center of the specimen overlaps the center of the spacing between the bars. Put the short side.

At the center of the test piece, weigh a rectangular parallelepiped with a weight of 1 、 g and a short side of 9 mm × long side of 15 mm or more so that the central axes of the long sides of the test piece and the weight are perpendicular to each other. When the piece is not broken or can be held for 5 seconds, the strength is set to 1 g, and a weight of 1 g is further applied, and holding for 5 seconds is repeated. If not broken, the operation of adding and holding a 1 g weight is repeated, and when the test piece breaks, the weight of the weight that can be held immediately before breaking is taken as the strength of the filler in the present invention.

It should be noted that the holding time is desirably fixed at 5 seconds. However, if the holding time is 10 seconds after 5 seconds, the measurement intensity is not affected. Therefore, it may be held for 5 to 10 seconds.

The long side of the weight is not particularly limited as long as it is 15 mm or more, but usually 25 mm is used. The test is performed 5 times, and the average value of 5 times is evaluated.

[Hoop material]
As the hoop material, a tape-shaped hoop material used for a normal spiral wound gasket can be used.

Examples of the material of the hoop material include stainless steel materials such as SUS304, SUS304L, SUS316, and SUS316L, and single metals and alloys such as aluminum, inconel, and hastelloy.

The thickness of the hoop material is usually set in the range of 0.1 to 0.3 mm, although it varies depending on conditions such as gasket dimensions, intended use, and required performance.

The cross-sectional shape of the hoop material is not only a curved line shape such as a V shape or M shape, but also a curved shape such as an arc shape or a wave shape, or a combination of a straight portion and a curved portion. it can.
[Spiral wound gasket]
The spiral wound gasket of the present invention includes a gasket body formed by winding the filler material and the hoop material in a spiral manner by a conventionally known method.

In the gasket body, a filler material other than the filler material may be used in combination. For example, the gasket main body may be formed using the filler material only in the inner peripheral portion and the outer peripheral portion and using a conventional expanded graphite filler material in the central portion.

The spiral wound gasket of the present invention may further include an inner ring member that is fitted to the inner periphery of the gasket body and / or an outer ring member that is fitted to the outer periphery of the gasket body.

Since the spiral wound gasket of the present invention has the above-described structure, it exhibits good sealing performance even in a highly oxidizing atmosphere, so that it can be used for petrochemical sealing materials, oil refining plant sealing materials, and the like. Useful.
[Example]
Hereinafter, the spiral wound gasket according to the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.
<Evaluation method of fiber diameter and fiber length>
Optical micrographs of inorganic fibers were taken and the diameter and length were measured.
Regarding the fiber length, there are those in which inorganic fibers break and become shorter. Therefore, when performing fiber length evaluation, a wide distribution occurs. In order to eliminate these effects, 100 optical fibers are randomly picked up and evaluated. Evaluation is made using the data of the top 50 percent with the longest fiber length (Table 2).

Also, the average fiber diameter was calculated from the fibers evaluated for fiber length. Each aspect ratio was also determined from each fiber diameter and fiber length. The measured data is listed in the table below. The evaluation results are also described below.

The measuring instrument was KEYENCE VHX-D510 (VHX DIGITAL MICROSCOPE), and the optical magnification was evaluated at 150 to 200 times.
[Example 1]
Inorganic filler (talc, clay, etc.): 78% by weight, inorganic fiber (rock wool): 6% by weight, organic fiber (aramid fiber): 8% by weight, organic binder (NBR): 8% by weight filler used. The form of the filler material was papermaking, and the thickness was 0.5 ± 0.05 mm. The average fiber diameter of rock wool was 11.05 μm, and the average fiber length was 774.05 μm. The average aspect ratio was 72.48.

In the above method, holding the weight for 5 seconds was repeated to evaluate the filler strength. After heating to remove the binder and organic fibers, the strength of the filler was measured. The heating conditions in Examples and Comparative Examples were 96 hours at 500 ° C. under air.

As a result, the filler strength was 13.0 g.
[Comparative Example 1]
Inorganic filler (talc, clay, etc.): 78% by weight, inorganic fiber (ceramic fiber): 6% by weight, organic fiber (aramid fiber): 8% by weight, organic binder (NBR): 8% by weight used. The form of the filler material was papermaking, and the thickness was 0.5 ± 0.05 mm. The average fiber diameter of the ceramic fibers was 8.73 μm, and the average fiber length was 996.50 mm. The average aspect ratio was 117.80.

In the same manner as in Example 1, the filler strength was evaluated by the method described above. After heating to remove the binder and organic fibers, the strength of the filler was measured.

As a result, the filler strength was 8.8 g.

DESCRIPTION OF SYMBOLS 1 ... Filler material 2 ... Hoop material 3 ... Inner ring ring member 4 ... Outer ring ring member 10 ... Gasket body

Claims

A spiral wound gasket comprising a gasket body formed by overlapping a filler material and a hoop material and winding them in a spiral shape,
The filler material comprises a sheet containing inorganic fibers,
A rectangular parallelepiped test piece having a length of 30 mm × short side of 15 mm and a thickness of 0.5 ± 0.05 mm is taken from the filler material, and the test piece is heated at 500 ° C. for 96 hours. Place on the two bars so that the short side is parallel to the bar and the center of the test piece overlaps the center of the interval, and the center of the test piece is 1 g in weight, and the dimensions are short side 9 Place a weight of a rectangular parallelepiped with a length of 15 mm or more on the long side so that the central axis of the long side of the test piece and the weight is perpendicular to each other, and when the test piece is not broken or held for 5 to 10 seconds, the strength is increased. 1g, repeat the holding for 5 to 10 seconds with a 1g weight, and the weight of the weight that can be held immediately before the specimen breaks is the filler strength, and the strength should be 9g or more. Spiral wound gasket characterized by.
The composition of the filler material ranges from 74 to 85% by weight of inorganic filler, 2 to 20% by weight of inorganic fiber, 2 to 20% by weight of organic fiber, and 4 to 12% by weight of organic binder (the total is 100% by weight) The spiral wound gasket according to claim 1.
The spiral wound gasket according to claim 1 or 2, wherein rock wool is included as the inorganic fiber.
The spiral wound gasket according to claim 3, wherein 75% by weight or more of the inorganic fiber is rock wool.
The spiral wound gasket according to any one of claims 1 to 4, wherein the average fiber diameter of the inorganic fibers is in the range of 11 to 20 µm.
The spiral wound gasket according to any one of claims 1 to 5, wherein the average aspect ratio of the inorganic fibers is in the range of 70 to 115.