JPH0233295B2 - PAIPUNOFURANJISETSUZOKUBUBUNNOHIFUKUHOHO - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of covering a flange connection part of a pipe, using a heat-shrinkable sheet having a specific adhesive layer and a heat-resistant filler having a specific shape. The purpose of the present invention is to provide a coating method that prevents the flange connection portion from being incompletely covered due to displacement of the heat-shrinkable sheet or the like by covering the flange connection portion.

Conventionally, in heavy chemical factory plants, piping for urban central heating, or piping around pump stations for crude oil and natural gas transportation pipelines, the shapes of the piping have been elbows, resistors, valves, and T-shaped pipes.
It has a wide variety of irregularly shaped parts such as joint pipes and flange connection parts, but if conventional heat-shrinkable coating materials are applied as is to these irregularly-shaped parts, the heat-shrinkable sheathing material will In addition to shrinking in the circumferential direction of the pipe, for example, the coating material may shift in the width direction, which is perpendicular to the direction of heat shrinkage (circumferential direction of the pipe), due to dimensional changes during heat shrinkage. As a result, the coating material has been displaced or peeled off from the surface of the portion of the irregularly shaped tube to be coated, or voids have been created.

For example, if the irregularly shaped part to be covered is a flange connection part of a pipe, if a heat-shrinkable coating material with a high heat shrinkage rate is wrapped around it and heat-shrinked, during the heat-shrinkage, The sheathing material that adheres tightly around the flange connection part due to heat shrinkage in the circumferential direction causes a large shift in the width direction of the sheathing material, and the sheathing material shifts from the flange connection part to one of the pipes, causing the sheath It has come off the flange connection part that should be overturned and its surroundings,
There was a problem that the flange connection part and its surroundings could not be covered. These problems were particularly noticeable when the pipe had a large diameter, since there is usually a limit to the width of the coating material.

As a result of intensive research into solving the problems that heat-shrinkable (anticorrosion) coating materials had when covering the above-mentioned flange connection parts, the present inventors found that
As the adhesive layer, we have adopted a heat-adhesive adhesive layer whose main component is an elastomer material, so that the shear strength related to the adhesive force of the adhesive can maintain a high value even at high temperatures where the coating material undergoes heat shrinkage. In addition, a heat-resistant filler having a specific shape is arranged at the flange connection part, that is, a bendable rod-shaped band formed by filling a heat-resistant porous material into a cylindrical body made of plastic film. By covering the flange connection part with the above-mentioned heat-shrinkable sheet, problems such as shearing of the heat-shrinkable coating material caused by heat shrinkage can be solved, and the flange connection part can be easily covered in good condition. I found out.

The present invention was made based on the above findings, and
In the method of covering the flange connection portion between flanged pipes or between a flanged pipe and a blind flange with an adhesive layer-coated heat-shrinkable sheet, first, the flange portion of the flange connection portion and the peripheral surface of the pipe in the vicinity thereof are coated. A bendable rod-shaped band formed by filling a heat-resistant porous material into a cylindrical body made of plastic film is placed between the two, and the rod-shaped band covers at least the bolt and nut portion of the flange connection portion. Next, a heat-shrinkable sheet having an adhesive layer that exhibits high shear strength at high temperatures (hereinafter referred to as a first heat-shrinkable sheet) is arranged in a cylindrical shape around the flange connection portion, and the first A flange for a pipe, characterized in that the entire heat-shrinkable sheet is heated and heat-shrinked to cover the flange connection part, including at least the rod-like band, and is bonded to the flange connection part by the adhesive layer. The present invention provides a method of covering a connection portion.

In the present invention, the flange portion refers only to the flange of the pipe, and the flange connection portion refers to the portion including the flange portion and the peripheral surface of the pipe in the vicinity of the flange continuous to the flange portion.

According to the method of covering a flange connection part of a pipe of the present invention, after covering at least the bolts and nuts of the flange connection part with a heat-resistant filler having a specific form, that is, the rod-like band, a first heat treatment is performed. When a shrinkable sheet is arranged in a cylindrical shape around the flange connection part of a pipe and subjected to heat shrinkage, the adhesive layer on the back side maintains high shear strength at the heat shrinkage temperature. During heat shrinkage, the flange connection part is covered and closely bonded to the flange connection part, and the first heat shrinkable sheet hardly shifts in the width direction at high temperatures and comes off from the flange connection part, and the first heat shrinkable sheet The adhesion effect of the shrinkable sheet and the combined effect of the rod-shaped band enable the flange connection portion of the pipe to be covered more reliably.

According to the method of covering a flange connection portion of a pipe according to the present invention, the heat-resistant filler is a lightweight and bendable material formed by filling a heat-resistant porous material into a cylindrical body made of plastic film. Since a rod-shaped band is used, even if the pipe has a large diameter, the heat-resistant filler can be easily coated on the flange connection portion, and the workability of this coating is significantly improved.

Furthermore, in the rod-shaped band used in the present invention, since the heat-resistant porous material having water absorption properties is covered with a cylindrical body made of plastic film, the risk of water supply due to the heat-resistant porous material is prevented. Corrosion protection of the covering portion can be ensured.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the method of covering a flange connection portion of a pipe according to the present invention will be described in detail based on its embodiments with reference to the drawings.

First, the first heat-shrinkable sheet 1 used in the present invention
To explain, the first heat-shrinkable sheet 1
The cross-linked plastic layer is coated with a thermal adhesive that exhibits high shear strength at high temperatures.

The cross-linked plastic layer is a cross-linked plastic film or sheet having known heat shrinkability,
Alternatively, it may be a crosslinked plastic layer formed from such a laminated sheet, and preferably has a heat shrinkage temperature of about 80 to 200°C, especially about 90 to 180°C, and a heat shrinkage rate of about 20 to 80%, preferably is 30-75%
degree, more preferably 40 to 50%,
Further, the degree of crosslinking of the polymer forming the film or sheet is preferably about 20 to 90%, particularly 25 to 80%, as expressed by the gel fraction described below.

Further, the adhesive layer of the first heat-shrinkable sheet 1 is formed at a high temperature (for example, also referred to as a heat-shrinkage temperature, approximately 80 to 200°C) at which the heat-shrinkable crosslinked plastic layer exhibits the greatest heat shrinkage force. within the range of about 0.002 to 0.05 Kg/ ^cm2 , preferably
^Shear strength (ASTM
An adhesive consisting mainly of an elastomer material that exhibits an adhesive force expressed as be.

As mentioned above, this adhesive layer maintains adhesive strength at high temperatures, and at room temperature (around 20℃)
In this case, it is appropriate to use an adhesive having a shear strength of about 0.8 to 30 Kg/cm ² , particularly about 1.0 to 30 Kg/cm ² .

Further, the adhesive layer may be made of an olefinic elastomer such as polyisobutene rubber (IIR; butyl rubber), ethylene-propylene copolymer rubber (EPR), ethylene-propylene-nonconjugated diene copolymer rubber (EPDM), or polybutadiene rubber. Other products such as rubber, polyisoprene rubber, styrene-butadiene copolymer rubber, acrylonitrile-butadiene copolymer rubber, chloroprene rubber, chlorosulfonated polyethylene rubber, acrylic rubber, epichlorohydrin rubber, chlorinated polyethylene rubber, fluorinated rubber, etc. Approximately 30 to 70% by weight of elastomer components such as non-conjugated diene elastomers,
In particular, the content is preferably 35 to 65% by weight.

In addition to the elastomer component, the adhesive layer also contains other modifying polymers (modifying polymers) that are generally contained in adhesives, tackifiers, corrosion inhibitors, and inorganic fillers. etc. may be blended.

The adhesive layer in the first heat-shrinkable sheet 1 used in the present invention contains about 30 to 70% by weight of the aforementioned olefin elastomer and about 1 to 20% by weight of the modifying polymer.
A heat-adhesive adhesive composition containing approximately 10 to 30% by weight of tackifier and approximately 0 to 20% by weight of inorganic filler has an adhesive strength (shear strength) of approximately 1.0 kg/kg even at room temperature. ^cm2 or more, and the adhesive strength at high temperature (shear strength) is about 0.01Kg/cm2 ^or more at 80℃, 100
It is ideal as it has a high value of approximately 0.005Kg/cm ² or more at °C.

In the first heat-shrinkable sheet 1 used in the present invention, if the elastomer component in the adhesive layer becomes too small, the heat-shrinkage temperature of the crosslinked plastic layer will be about 80°C, similar to a general hot melt type adhesive. It is not suitable because the shear strength of the adhesive becomes extremely small or rapidly decreases at temperatures above ℃. Also, if the elastomer component is too large, the adhesive force after cooling to room temperature becomes small, so it is not suitable. do not have.

The tackifier is used to impart fluidity to the adhesive,
It is blended mainly for the purpose of imparting toughness, and if too little is used, these properties will be lost, which is undesirable.

In a preferred embodiment of the coating method of the present invention, after the first heat-shrinkable sheet covers the flange connection part, the flange connection part is further bonded to the flange connection part in order to ensure coverage of the flange connection part. Another heat-shrinkable sheet with an adhesive layer is further coated on top of the first heat-shrinkable sheet. Similar to the first heat-shrinkable sheet 1, a heat-adhesive adhesive layer is provided on the entire surface of the cross-linked plastic layer, and the adhesive forming the adhesive layer is An adhesive having high shear strength at high temperatures used in heat-shrinkable sheet 1 is preferred, but a conventional hotmel type adhesive may also be used.

Further, the rod-shaped band 2 as a heat-resistant filler used in the present invention has a heat-resistant porous material 2 in a cylindrical band 22 made of plastic film, as shown in FIG.
It is a bendable band-shaped material filled with 3, which mainly covers the bolts and nuts that connect the flange parts, and as shown in Fig. and the peripheral surface of the pipe. The cylindrical band 22 forming this rod-shaped band 2 usually has a circumference of 100 to 1000 mm, and depending on the pipe to be coated, a band slightly longer than the outer circumference is used. The heat-resistant porous material 23 is preferably heat-resistant and lightweight, such as glass wool or asbestos. In addition, the heat-resistant porous material 23 is made of a short rod-shaped body 2 as shown in FIG.
It is preferable that a plurality of rod-shaped bodies 23' are filled in the cylindrical body 22 in series. The preferred cross-sectional size for each piece is 50mm long x 100mm wide.
mm ~ 200mm long x 300mm wide, and the preferred length is 50mm ~
It is 200cm. Moreover, in order to facilitate the joining of both ends of the rod-like band 2 after it is arranged at the flange connection part, as shown in FIG. It is preferable to do so.

Next, using the above-mentioned first heat-shrinkable sheet 1, second heat-shrinkable sheet 3, and the rod-shaped band 2 shown in FIG. , the case of coating in the form will be explained in accordance with the preferred order of construction with reference to FIGS. 2 to 4. It will be easily understood that the same method can be used to cover the flange connection portion between the flanged pipe and the blind flange.

For the above-mentioned coating, first, the rod-shaped band 2 (not shown in FIG. 3 for convenience) is applied to the flange portions 11, 11 of the flange connection portion 10 and their surrounding areas, as shown in FIGS. 2 and 4. Pipe peripheral part 1
2 and 12, both ends of the rod-shaped band 2 are connected by an appropriate method, and the bolts and nuts 13, 13 that fasten the flange parts 11, 11 are covered.
Next, as shown in FIG. 3, the first heat-shrinkable sheet 1 (indicated by the dashed dotted line) was coated with a conventional plastic covering material 20, 20, except for the flange connection portion and its surrounding area. Pipe A, A
The first heat-shrinkable sheet 1 was placed around the flange connection part 10, and both ends of the first heat-shrinkable sheet 1 were overlapped, and the overlapped parts were connected with heat-sealing tape 4 to form a cylindrical shape, and then a cylindrical shape was formed. While heating the first heat-shrinkable sheet 1 with the flame of a gas burner and heat-shrinking it, the flange connection portion 10 including the rod-shaped band 2 and one pipe A (top left in FIG. 4) are heated.
The first heat-shrinkable sheet 1 is attached to the flange connection portion 10 including the rod-like strip 2 by an adhesive layer that exhibits high shear strength at high temperatures by further heating. After joining, the flange connection portion 10, the peripheral surface 12 of one pipe A, and the plastic material 20 are covered, as shown in FIG. Due to this construction, in contrast to known heat-shrinkable covering materials, the covering material would shift from the flange connection portion 10 to one of the flange sides during heat shrinkage.
According to the first heat-shrinkable sheet 1 used in the present invention, due to the adhesive layer having high shear strength at high temperatures, it does not shift during heat shrinkage unlike conventional heat-shrinkable sheets.

Then, to further ensure coverage of the flange connection portion 10, a second heat-shrinkable sheet 3 with an adhesive layer (preferably the same as the first heat-shrinkable sheet 1) is applied to the second heat-shrinkable sheet 3. Arranged around the joined flange connection portion 10 of one heat-shrinkable sheet 1 and overlapping both ends of the heat-shrinkable sheet 3,
The overlapped parts are connected with a heat seal tape (not shown) to form a cylindrical shape, and the cylindrical heat-shrinkable sheet 3 is heated with the flame of a gas burner to heat-shrink it while being joined. The corresponding part of the flange connection part 10 in the first heat-shrinkable sheet 1 and the peripheral surface of the other pipe A (top right in FIG. 4) which is not covered by the first heat-shrinkable sheet 1 12 and the plastic material 20, and further heated to join the heat-shrinkable sheet 3 with its adhesive layer in the same manner as in the case of the first heat-shrinkable sheet 1, as shown in FIG. Cover.

The method of coating a flange connection part of a pipe according to the present invention is mainly suitable for coating a flange connection part of a pipe with a large diameter of 25 to 500 cm, and it is particularly preferable to coat the flange connection part of a pipe as shown in FIG.

However, the method for coating a flange connection portion of a pipe according to the present invention is not limited to the illustrated embodiment, and when applying the method for coating a flange connection portion of a pipe according to the present invention to a small pipe with a diameter of 25 mm or less. For example, after covering and bonding the first heat-shrinkable sheet 1 to the flange connection portion 10, the second heat-shrinkable sheet 3 is applied to the entire surface of the first heat-shrinkable sheet 1, and the pipe A , A and the plastic materials 20, 20 may be covered and bonded.

Further, the covering form of the rod-like band 2 is not limited to the form shown in FIG. 2, but as shown in FIG. It is preferable to do this.

According to the method of covering the flange connection portion of a pipe of the present invention, as described above, first, at least the bolts and nuts that connect the flange portions to each other are covered with a rod-shaped band as a heat-resistant filler, and then ,
The first heat-shrinkable sheet is coated with the heat-resistant filler and bonded to the flange connection part, and as a result, the first heat-shrinkable sheet is reliably bonded to the flange connection part without causing any "slippage." Then, by overlapping and bonding the second heat-shrinkable sheet to the first heat-shrinkable sheet, the flange connection part can be covered more reliably, and it is lightweight and bendable. Since the rod-like strip is used, the rod-like strip can be easily covered with a heat-resistant porous material.

Below, test examples and examples of the present invention regarding the adhesive forming the adhesive layer of the first heat-shrinkable sheet used in the present invention will be shown together with comparative test examples and comparative examples.

In addition, in the test examples and comparative test examples, the shear strength of the adhesive was measured using two iron plates (125 mm x 25 mm x 1.5
mm) overlapped by 12 mm, adhesive was interposed between the overlapping parts, heated to a joining temperature of 130°C for about 5 minutes, the steel plates were joined, and the steel plates were simultaneously pulled in the direction of both ends using a universal testing machine. ASTM D 1002
was measured according to the measurement direction.

Test Example 1 After kneading the adhesive having the composition shown below using a kneader at a temperature of 150°C for 5 minutes, it was rolled to a size of 1.5 mm.
The thickness of the adhesive was as follows.

Bruti rubber 25% by weight ethylene-propylene-nonconjugated diene copolymer
30% by weight Polybutene 5% by weight Coumarone-indene resin 20% by weight Talc 10% by weight This adhesive sheet was measured using the above-mentioned shear strength measurement method, and the shear strength was 0.014Kg/cm ^{2 at 105℃ and 0.014Kg/cm 2} at 80℃.
It was 0.029Kg/cm ² and further 1.15Kg/cm ² at 20°C.

Comparative Test Example An adhesive sheet (comparative adhesive) was formed in the same manner as in Test Example 1, except that the composition of the adhesive was changed as follows.

Ethylene-propylene-nonconjugated diene copolymer
20% by weight Ethylene-ethyl acrylate copolymer 25% by weight Coumaron-indene resin 45% by weight Microwax 10% by weight This adhesive sheet was measured using the above-mentioned shear strength measurement method, and the result was 0.001Kg/cm at 105℃. ² , at 80℃
The shear strength is 0.124Kg/ ^cm2 , and at around 110℃, the shear strength decreases to a very small extent, and furthermore, at 20℃, it decreases to 24.2Kg/cm2.
It was Kg/ ^cm2 .

Example This example shows an example in which the flange connection portion is coated in the form shown in FIG.

The adhesive sheet obtained in the above test example was used as a cross-linked plastic sheet (thickness 1.0 mm, gel fraction 60%,
Heat shrinkage rate in length direction: 45%, heat shrinkage temperature: 105℃)
The first heat-shrinkable sheet used in the present invention (thickness: 2.5 mm, width: 900 mm, length;
4500mm sheet) was formed.

First, the rod-shaped band 2 (the circumference of the cylindrical body is 650 mm,
As shown in Fig. 2, 4.3 glass wool rods (length 4300 mm, size 150 mm x 150 mm x 1000 mm) are placed on the pipe circumferential surfaces 12, 12 on both sides of the flange portions 11, 11, and their ends are They are tied together and the bolt and nut parts 13, 13 are covered.

Next, as shown in FIG. 3, the above-mentioned first heat-shrinkable sheet 1 was attached to the flange connection portion of the pipes A (outer diameter of the pipe: 1067 mm, outer diameter of the flange;
1345mm) and heat seal tape 4
The two end faces of the sheet are joined to form a cylinder, and the cylindrical heat-shrinkable sheet 1 is heated with the flame of a gas burner.
The flange connection part 10 including the rod-like strip 2 is heated to 105 to 110°C and heat-shrinked to form a flange connection part 10 including the rod-shaped band 2, as shown in FIG.
Then, the adhesive is applied to the peripheral surface 12 of one pipe A (top left in FIG. 4) and the plastic covering material 20, and heating is continued to apply the adhesive to the position where the heat-shrinkable sheet 1 is brought into close contact. It was joined with

After that, the second heat-shrinkable sheet 3 (heat shrinkage rate: 45%, thickness: 2.5 mm, width: 900 mm, length: 4500
The second heat-shrinkable sheet 3 is covered with the first heat-shrinkable sheet 1. Similarly, flange connection part 1
From above the first heat-shrinkable sheet 1 joined to the first heat-shrinkable sheet 1, the flange connection portion 10 and the peripheral surface of the other pipe A (top right in FIG. 4) that is not covered with the first heat-shrinkable sheet 1 are inspected. 12 and plastic material 20.

As a result, the first heat-shrinkable sheet 1 and the second heat-shrinkable sheet 2 do not cause "slippage" at the flange connection part 10, and as shown in FIG. was formed.
In addition, the workability when using the bar-shaped strip 2 is as follows:
It was far superior to the case where glass wool was used instead of without filling the cylindrical body 22.

Comparative Example A heat-shrinkable sheet using the adhesive obtained in the comparative test example above as the adhesive layer in the heat-shrinkable sheet instead of the first heat-shrinkable sheet used in the above example (comparative sheet) The flange connection portion 10 was coated in exactly the same manner as in the above example except that the flange connection portion 10 was used.

As a result, when covering the flange connection portion 10 with the comparative sheet, the comparative sheet was coated with about 105
When heated above ℃, abnormal "slippage" occurs on one pipe side of the flange connection part 10,
This "slippage" was further increased by heating during covering with the second heat-shrinkable sheet, and a portion of the flange connection portion 10 was exposed.

Moreover, when this comparative example was carried out without using the rod-shaped band 2, the above-mentioned "misalignment" was even more significant.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing an example of a rod-like band, FIG. 2 is a perspective view showing a manner in which the flange connection portion of the rod-like band is covered in an embodiment of the present invention, and FIG. 3 is an embodiment of the present invention. FIG. 4 is a perspective view of a main part showing how the first heat-shrinkable sheet is applied to a flange connection part, and FIG. 4 is a part showing a main part of an example of a flange connection part covered by the coating method of the present invention. FIG. 3 is a cross-sectional side view. A... Pipe, 1... Heat-shrinkable sheet (first heat-shrinkable sheet), 2... Rod-shaped band, 3... Another heat-shrinkable sheet (second heat-shrinkable sheet), 4...
Heat sheet tape, 10...Flange connection part, 11...Flange part, 12...Pipe peripheral surface part, 13...Bolt and nut part, 20...Plastic covering material, 22...Plastic film cylindrical body , 23...Heat-resistant porous material, 2
3'...rod-shaped body.

Claims (1)

[Claims] 1. A method for covering the flange connection portions of flanged pipes with each other or between a flanged pipe and a blind flange with a heat-shrinkable sheet having an adhesive layer,
First, a bendable rod-shaped band formed by filling a heat-resistant porous material in a cylindrical body made of plastic film is disposed between the flange part and the peripheral surface of the pipe in the vicinity of the flange part in the flange connection part. The rod-shaped band covers at least the bolts and nuts of the flange connection part, and then a heat-shrinkable sheet having an adhesive layer that exhibits high shear strength at high temperatures is placed around the flange connection part in a cylindrical shape. , and while heating the entire heat-shrinkable sheet to heat-shrink it, cover the flange connection portion including at least the rod-like band and bond it to the flange connection portion with the adhesive layer. How to cover the flange connection part of a pipe. 2. The heat-resistant porous material consists of short rod-shaped bodies,
The method for covering a flange connection portion of a pipe according to claim 1, wherein a plurality of the rod-like bodies are packed in series.