JPS6076326A - Covering process for flange connecting part of pipe - Google Patents

Abstract

PURPOSE:To prevent the occurrence tendency of the imperfect covering for a flange connecting part by covering said flange part, while using the heat shrinkable sheet with a specified adhesive layer, and by using together a heat resisting filler. CONSTITUTION:The rod like belt 23' which is foldably formed, while filling the tubular body 22 made of plastic film with a heat resisting porous material 23, e.g. glass wool or asbestos, is arranged in between the flange part 11 in a flange connecting part 10 and the peripheral surface parts 12 of pipes adjacent to the flange part. At least bolts and nuts portion 13 of said flange connecting part is covered with said rod like belt. Next, the heat shrinkable sheet 1 provided with the adhesive layer with high shear strength at high temperature, is cylindrically arranged around the flange connecting part 10. The flange connecting part 10 including at least said rod like belt 23' is covered with said sheet and the pipes are connected, shrinking the heat shrinkable sheet by heating.

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 becoming incompletely covered due to slippage of the heat-shrinkable sheet or the like by covering the flange connection portion.

Conventionally, the shape of pipes in heavy chemical factory plants, pipes for urban central heating, or pipes around pump stations for crude oil and natural gas transportation pipelines have been shaped like elbows,
It has a wide variety of irregularly shaped parts such as reducers, valves, T-shaped pipes, and flange connection parts, but if conventional heat-shrinkable coating materials are applied to these irregularly-shaped parts as is, the heat-shrinkable In addition to the shrinkage of the coating material in the circumferential direction of the tube, for example, the displacement in the width direction of the coating material in the direction perpendicular to the direction of heat shrinkage (circumferential direction of the tube), The dimensional change caused a considerable amount of change, and as a result, the coating material was displaced or peeled off from the surface of the portion of the irregularly shaped tube to be coated, and voids were formed.

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 coating 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 coating material, and it shifts from the flange connection part to one of the pipe sides, causing the coating material to become stuck. There was a problem that the flange connection part and its surroundings could not be covered because it would come off the flange connection part and its surroundings. Such problems were particularly noticeable when the pipe had a large diameter, since there is usually a limit to the width of the coating material.

The present inventors have conducted extensive research into solving the problems that heat-shrinkable (anti-corrosion) coating materials had when covering the above-mentioned flange connection parts. Adopts a heat-adhesive adhesive layer mainly composed of an elastomer material that can maintain a high value of shear strength related to the adhesive force even at high temperatures, and has a specific shape in the flange connection part. A heat-resistant filler, that is, a bendable rod-shaped band formed by filling a heat-resistant porous material into a cylindrical body made of plastic film, is arranged, and the flange connection portion is formed with the heat-shrinkable sheet. It has been found that by coating the heat-shrinkable coating material, problems such as shearing caused by the heat-shrinking material can be solved, and the flange connection portion can be easily coated in good condition.

The present invention has been made based on the above findings, and includes a method of covering the flange connection portions between flanged pipes or between a flanged pipe and a blind flange with a heat-shrinkable sheet having an adhesive layer. between the flange part and the pipe peripheral part in its vicinity,
A bendable rod-like band formed by filling a heat-resistant porous material into a cylindrical body made of plastic film is arranged, and the rod-like band covers at least the bolts and the pads of the flange connection part, and then heated to a high temperature. A heat-shrinkable sheet (hereinafter referred to as a first heat-shrinkable sheet) having an adhesive layer exhibiting high shear strength is arranged in a cylindrical shape around the flange connection part, and the first heat-shrinkable sheet A method for covering a flange connection portion of a pipe, the method comprising: covering the flange connection portion, including at least the rod-shaped band, while heating the entire body to thermally shrink it; and bonding the flange connection portion to the flange connection portion with the adhesive layer. It provides:

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 according to the present invention, after covering the bolt and nut part of the flange connection part with a heat-resistant filler having a specific form, that is, the rod-like band, , when the first heat-shrinkable sheet is arranged in a cylindrical shape around the flange connection part of the pipe and heat-shrinked, the adhesive layer on the back side maintains high shear strength at the heat-shrinkage temperature. Therefore, the first heat-shrinkable sheet covers the flange connection part and is tightly bonded to the flange connection part during heat shrinkage, and there is almost no problem of the first heat shrinkable sheet shifting in the width direction and coming off from the flange connection part at high temperatures. Combined with the adhesive effect of the first heat-shrinkable sheet and the combined effect of the rod-shaped band, the flange connection portion of the pipe can 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-like 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 a water-absorbing property is covered with a cylindrical body made of plastic film, the risk of water absorption by 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, to explain the first heat-shrinkable sheet 1 used in the present invention, the first heat-shrinkable sheet 1 has a heat-adhesive adhesive layer that exhibits high shear strength at high temperatures on the entire surface of the crosslinked plastic layer. It is configured with the following.

The above-mentioned crosslinked plastic layer may be a crosslinked plastic layer formed from a known heat-shrinkable crosslinked plastic film or sheet, or a laminated sheet thereof (preferably, the heat-shrinkage temperature is about 80 to 200°C,
In particular, the temperature is about 90 to 180℃, and the heat shrinkage rate is about 20 to 8.
0%, preferably about 30 to 75%, more preferably 4
0 to 50% is used, and the degree of crosslinking of the polymer forming the film or sheet is approximately 20 to 90%, particularly 25 to 8%, as expressed by the gel fraction described below.
Preferably it is 0%.

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 2
0.002~0.00℃).
Within the range of 0.05 kg/cnl, preferably from 0.005 to
Shear strength within the range of 0.04-kg/- (ASTM
An adhesive consisting mainly of an elastomer material, which exhibits an adhesive strength expressed as D 1002 ) and whose shear strength does not immediately drop rapidly even if the temperature is raised above its heat shrinkage temperature. be.

As mentioned above, this adhesive layer maintains adhesive strength at high temperatures, and at room temperature (around 20°C), it maintains adhesive strength of about 0.
It is appropriate to use an adhesive that exhibits a shear strength of about 8 to 3 Qkg/cJ, particularly about 1.0 to 30 kg/cd.

Further, the adhesive layer may be made of, for example, polyisobutyne rubber (
IIR; butyl rubber), olefin elastomers such as ethylene-propylene copolymer rubber (EPR), ethylene-propylene-nonconjugated diene copolymer rubber (EPDM), polybutadiene rubber, polyisoprene rubber, styrene-butadiene copolymer rubber - Elastomers such as composite rubber, acrylonitrile-butadiene copolymer rubber, chloroprene rubber, chlorosulfonated polyethylene rubber, acrylic rubber, epichlorohydrin rubber, chlorinated polyethylene rubber, and other non-conjugated diene-based elastomers such as fluoride and hepta-component rubbers. The ingredients are about 30-70% by weight, especially 35-65% by weight.
It is preferable that the content is % 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 olefinic Ella 9-stomer and about 1 to 20% by weight of the modifying polymer.
% by weight, about 10 to 30% by weight of tackifier, and about 0 to 20% by weight of inorganic filler, the adhesive strength (shear strength) at room temperature is about 1. 0kg
/- or more, and still have adhesive strength (shear strength) at high temperatures
It is optimal because it is higher than about 0.01 kg/cJ at 80'c and about 0.005 k+r/cd at 100°C.

In the first heat-shrinkable sheet 1 used in the present invention,
: If the elastomer component in the adhesive layer becomes too low, the shear strength of the adhesive will become extremely low at the heat shrinkage temperature of the crosslinked plastic layer of about 80°C or higher, similar to general true melt type adhesives. This is not appropriate because the adhesive strength decreases rapidly, and if the elastomer component is too large, the adhesive strength after being cooled to room temperature decreases, which is not appropriate.

The tackifier is blended primarily to impart fluidity and tankability to the adhesive, and if the amount is too small, these 10- characteristics will be lost, which is not desirable.

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, the sheet has a heat-adhesive adhesive layer provided on the entire surface of the crosslinked plastic layer, and the adhesive forming this adhesive layer is as follows: An adhesive having high shear strength at high temperatures used for the first heat-shrinkable sheet 1 is preferred, but a normal bot-melt type adhesive may also be used.

Further, the rod-shaped band 2 as a heat-resistant filler used in the present invention is a bendable material formed by filling a heat-resistant porous material 23 into a cylindrical body 22 made of plastic film, as shown in FIG. It is a strip-like material that mainly covers part of the bolts and nano l which connect the flange parts,
As shown in FIG. 2, it is disposed between the flange portion of the flange connection portion and the pipe circumferential surface portion around the flange portion.

The cylindrical body 22 forming this rod-like band 2 usually has a circumference of 100 to 1000 mm, and is slightly longer than the outer circumference depending on the pipe to be covered.

The heat-resistant porous material 23 is preferably heat-resistant and lightweight, such as glass wool or asbestos. Furthermore, as shown in FIG. 1, the heat-resistant porous material 23 consists of short rod-shaped bodies 23'', and it is preferable to fill the cylindrical body 22 with a plurality of these rod-shaped bodies 23'' in series. Part 1
The preferred cross-sectional size per piece is 50 x x x
The width is 100 m x the width is 300 m, and the preferred length is 50 to 200 cm. 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 described 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, a rod-like band 2 (not shown in FIG. 3 for convenience) is applied to the flange portion 11.11 of the flange connection portion 10 and its surrounding area, as shown in FIGS. 2 and 4. Both ends of the rod-shaped band 2 are arranged on the pipe circumferential surface 12°12 and connected by an appropriate method, and the flange portion 11.11
Cover the bolts and NAND parts 13.13 that fasten them. Next, as shown in FIG. 3, the first heat-shrinkable sheet 1 (indicated by the dashed line) is coated with a conventional plastic covering material 20, except for the flange connection part and its surrounding area.
．． 20, placed around the flange connection portions 10 of the pipes A and A, overlapping both ends of the first heat shrinkable sheet 1, and connecting the overlapping portions with heat seal tape 4. The first heat-shrinkable sheet 1, which has been made into a cylinder, is heated with the flame of a gas burner to heat-shrink it, while the flange connection portion 10 including the rod-shaped band 2 and one side of the heat-shrinkable sheet 1 are Pipe A (4th
The first heat-shrinkable sheet 1 is made by closely contacting the peripheral surface 12 and the plastic material 20 (left side in the figure) and further heating.
is bonded to the flange connection part 10, including the rod-shaped band 2, by an adhesive layer that exhibits high shear strength at high temperatures, as shown in FIG. By this construction, the coating material was displaced from the flange connection part 10 to one of the pipes during heat shrinkage with known heat-shrinkable coating materials, whereas this method According to the first heat-shrinkable sheet 1 used in the 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.

-14- Next, in order to further ensure the coverage of the flange connection part 10, a second heat-shrinkable sheet (preferably the same as the first heat-shrinkable sheet 1) 3 with an adhesive layer is applied. of,
The heat-shrinkable sheet 3 is placed around the joined flange connection portion 10 of the first heat-shrinkable sheet 1, and both ends of the heat-shrinkable sheet 3 are overlapped, and the overlapping portion is sealed with a heat seal tape (not shown). The first heat-shrinkable sheet 1 is connected to form a cylindrical shape, and the cylindrical heat-shrinkable sheet 3 is heated with the flame of a gas burner to heat-shrink the first heat-shrinkable sheet 1.
and the corresponding part of the flange connection part 10 in
The other pipe A that is not covered with the heat-shrinkable sheet 1
(Top right side in Figure 4) is brought into close contact with the peripheral surface 12 and the plastic material 20, and further heated to form a heat-shrinkable sheet 3 with its adhesive layer, similar to the case of the first heat-shrinkable sheet 1. They are joined in the same manner and covered as shown in FIG.

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 large diameter pipe 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 of coating the flange connection portion of a pipe according to the present invention is not limited to the embodiment shown in the drawings;
When applying the method of covering a flange connection portion of a pipe according to the present invention to a pipe having a small diameter of 1.5 mm or less, for example, after covering and joining the first heat-shrinkable sheet 1 to the flange connection portion 10, 2 heat-shrinkable sheet 3 to the first heat-shrinkable sheet 3
The entire surface of the heat-shrinkable sheet 1, the peripheral surface 12 of the pipe A, A
The plastic material 20.20 may also 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 a flange connection part of a pipe of the present invention, as described above, first, at least the bolts and the nand parts that connect the flange parts to each other are covered with a rod-like band as a heat-resistant filler, and then , the first heat-shrinkable sheet is coated with the heat-resistant filler and joined to the flange connection part, and as a result, the first heat-shrinkable sheet reliably connects the flange 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 a possible rod-like band is used, the rod-like band can be easily coated as 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 (125w x 25w x 1.5mm)
12f1 stacked on top of each other, with adhesive interposed between the overlapped parts, heated to a bonding temperature of 130°C for about 5 minutes to join the steel plates, and pulled simultaneously in the direction of both ends using a universal testing machine, and measured according to ASTM D1002. Measured according to the method.

17- Test Example 1 An adhesive having the composition shown below was kneaded in a kneader at a temperature of 150° C. for 5 minutes, and then rolled into an adhesive sheet having a thickness of 1.5 mm.

Butyl rubber 25% by weight Ethylene-propylene-non-conjugated 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 was found to be 105% by weight. 0.014 kg/cd at ℃, 0.029 kg/cd at 80℃! and further 1. at 20°C.
It was 15 kg/-.

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

Ethylene-propylene-non-conjugated diene copolymer 20M mass% 18- Ethylene-ethyl acrylate copolymer 25% by weight Coumarone-indene resin 45% by weight Microwax 10% by weight This adhesive sheet was measured for shear strength as described above. As a result of measurement using the method, 0.001 kglcsA at 105°C, 80
℃ is O, 124 kgl c+J, and around 110℃, the shear strength decreases to a very small extent, and
It was 24.2 kgl ct& at 0°C.

Embodiment This embodiment 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 on one side of a cross-linked plastic sheet (thickness 1.0 mm, gel fraction 60%, heat shrinkage rate in the length direction 45%, heat shrinkage temperature 105°C). The first heat-shrinkable sheet used in the present invention (thickness: 2.5 cm, width 1900 mm, length 14500 m) was formed.

First, the rod-shaped band 2 (the circumference of the cylindrical body is 650 Il 1 m)
, length 4300mm, 4.3 glass wool rods,
Size of one piece, 150mmX150mmX1000+n
As shown in FIG. 2, the tubes m) are placed on the pipe circumferential surface portions 12.12 on both sides of the flange portion 11.11, their ends are tied together, and the bolts and the NAND portions 13.13 are covered.

Next, as shown in FIG. 3, the first heat-shrinkable sheet 1 is wrapped around the flange connection portion of the pipes A (outer diameter of the pipe: 11,067 mm, outer diameter of the flange: 1:1,345 mm) and heat-sealed. Both ends are joined with tape 4 to form a cylindrical shape, and the cylindrical heat-shrinkable sheet 1-1 is
The flange connection part 10 including the rod-shaped band 2 and one pipe A (top left in Fig. 4) are heated to about 105-110°C with the flame of a gas burner and heat-shrinked, as shown in Fig. 4. The heat-shrinkable sheet 1 is made by closely contacting the peripheral surface 12 and the plastic covering material 20 and continuing heating.
The above adhesive layer was used to bond the parts in close contact with each other.

After that, the second heat-shrinkable sheet 3 (heat shrinkage rate: 45%
, Thickness: 2゜51, Width: 1900mm, Length: 4500+
+n sheet, the adhesive layer sheet obtained in the above comparative test example was used as the adhesive layer), and the second heat-shrinkable sheet 3 was bonded to the first heat-shrinkable sheet 1-1. In the same way as the coating, from the second part of the first heat-shrinkable sheet 1 joined to the flange connection part 10, the other pipe A (which is not covered with the flange connection part 10 and the first heat-shrinkable sheet 1) is The plastic material 20 and the peripheral surface portion 12 (upper right side of FIG. 4) were joined together.

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.

Note that the workability when using the rod-like band 2 was significantly superior to that when glass wool was used instead of the rod-like band 2 without filling the cylindrical body 22.

Comparative Example 21 - Using the adhesive obtained in Comparative Test Example 21 as an adhesive layer in the heat-shrinkable sheet instead of the first heat-shrinkable sheet used in Example 2. The flange connection portion 10 was covered in exactly the same manner as in the above example except that a shrinkable sheet (comparative sheet) was used.

As a result, the flange connection part 10 according to the above comparison sheet
When the comparative sheet is heated to about 105° C. or higher when covering, an abnormal "shift J" occurs on one pipe side in the flange connection part 10, and this "shift" is covered with a second heat-shrinkable sheet. The damage further increased due to the heating during the process, and a portion of the flange connection portion 10 was exposed.

Furthermore, in this comparative example, when the test was carried out without using the rod-shaped band 2, the above-mentioned "deviation J" was even more significant.

[Brief explanation of the drawing]

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. It is a partially sectional side view shown. A...Vibrator...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 portion 11...Flange portion 12...Vibe peripheral surface portion 13 ...Bolt and NAND part 20...Plastic covering material 22...Plastic film cylindrical body 23...
Heat-resistant porous material 23° Rod-shaped body patent applicant Ube Industries Co., Ltd. 23-

Claims (1)

[Claims] +11 In a method of covering the flange connection portion between flanged pipes or between a flanged pipe and a blind flange with a heat-shrinkable sheet with an adhesive layer, first, the flange portion and its vicinity in the flange connection portion are coated with a heat-shrinkable sheet with an adhesive layer. A bendable rod-shaped band formed by filling a heat-resistant porous material into a cylindrical body made of plastic film is disposed between the circumferential surface of the pipe and the flange connection portion. Next, a heat-shrinkable sheet having an adhesive layer that exhibits high shear strength at high temperatures is arranged in a cylindrical shape around the flange connection part, and the entire heat-shrinkable sheet is heated. A method for covering a flange connection part of a pipe, which comprises: covering the flange connection part (including the rod-shaped band) with a small amount while thermally shrinking the pipe, and bonding the flange connection part to the flange connection part with the adhesive layer. (2) The method for covering a flange connection portion of a pipe according to claim 11, wherein the heat-resistant porous material is made of short rod-like bodies, and a plurality of the rod-like bodies are packed in series.