JPH0581437B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION "Industrial Application Field" The present invention is applicable to high-temperature and/or
Alternatively, the present invention relates to a heat-retaining pipe for keeping high-pressure fluid warm and a method for manufacturing the same.

``Conventional technology'' Conventionally, in order to keep the fluid in the pipeline warm, a heat insulating material was wrapped around the outer circumference of the metal pipes that make up the pipeline. There are also bend-shaped pipes, and there are various parts that require heat insulation, so there are problems in that wrapping the insulation material requires on-site work, which increases the number of work days and makes the cost relatively high. . In particular, field work in remote locations such as foreign countries requires the dispatch of engineers and the transportation of materials and tools, resulting in high costs. Furthermore, simply wrapping a heat insulating material around the pipe does not provide a sufficient heat retaining effect, and there have been cases where the fluid in the pipe cannot be maintained within a desired temperature range.

The flexible heating tube described in Japanese Patent Application Laid-Open No. 50-113094 includes a flexible conduit, at least one electrical resistance conductor spirally arranged on the wall of the conduit, and at least one fibrous temperature conductor. This is a flexible heating tube especially intended for use in the medical field, which is characterized by a measuring probe, so that the flexible heating tube does not need to be tightly joined to the outer periphery of a straight or bent cylindrical pipe. When a flexible heating tube is used to insulate a fluid flowing in a pipeline, the high temperature and/or pressure of the fluid is applied to the flexible heating tube, causing damage to the flexible heating tube. There is a disadvantage that the fluid in the pipeline cannot be heated well.

In addition, the method for manufacturing a hose with heating wire described in Japanese Patent Application Laid-open No. 59-49945 includes a receiving strip formed with a dovetail groove that protrudes along one end edge and opens on one side inside, and a receiving strip formed on the other end edge. an insertion strip that is molded to protrude in the same direction and parallel to the receiving strip along the line and that is fitted into the dovetail groove; A band-shaped member made of a flexible and pliable electrical insulating material and having a holding strip that holds a heating wire is wound spirally along the outer surface of the cylindrical member. Since this is a manufacturing method in which the insertion strip is gradually fitted into the dovetail groove of the receiving strip to form a hose, and the cylindrical member is pulled out from the hose, it must be tightly joined to the outer periphery of a straight or bent cylindrical pipe. When a hose with a heated wire is used to keep a fluid in a pipeline warm, the high temperature and/or pressure of the fluid may be applied to the hose with a heated wire, causing damage to the hose with a heated wire. There is a disadvantage that there is a risk that the fluid in the pipeline cannot be heated well.

"Problems to be Solved by the Invention" The present invention has been made in view of the above-mentioned problems, and is capable of factory production, the degree of heat retention can be adjusted freely, and a fluid flowing through a pipeline. To provide a heat insulating pipe capable of satisfactorily heating a fluid in a pipeline without fear of damage even when the body is at high temperature and/or high pressure, and to provide a method for manufacturing the heat insulating pipe. The purpose is to

"Means and effects for solving the problem" According to the present invention, in a heat-retaining pipe for keeping a fluid flowing in a pipeline warm, a heating wire is installed between thermosetting welding rubber sheets. The sandwiched electric heating sheet is wrapped around a cylindrical pipe having a straight or bent shape, with a binder applied thereto so as to form a straight or bent shape along the outer periphery of the cylindrical pipe and having an annular cross section; There is provided a heat-retaining pipe characterized in that the electric heating sheet is heat-cured by heating while applying pressure through a synthetic rubber in a closed mold, and at the same time is closely bonded to the outer periphery of a cylindrical pipe. According to the heat-retaining pipe having the above-mentioned structure, an electric heating sheet consisting of a heating wire sandwiched between thermosetting welded rubber sheets is coated with a bonding agent around the outer periphery of a straight or bent cylindrical pipe. The electric heating sheet is tightly bonded to the outer periphery of the cylindrical pipe when it is wrapped and heated and cured at the same time, so that the electric heating sheet remains tightly bonded to the outer periphery of the cylindrical pipe after being heated and cured. The high-temperature, high-pressure fluid that flows can be satisfactorily heated, and there is no fear that the electric heating sheet will be damaged by the high-temperature, high-pressure fluid.

Further, according to the above configuration, the degree of heat retention can be adjusted by adjusting the value of the current flowing through the heating wire by comparing the temperature of the fluid flowing out from the heat retention pipe with the target temperature, or by adjusting the on/off time of the current. be adjusted. Furthermore, since the rubber sheet that holds the heating wires is both an electrical insulator and a heat insulator, the amount of heat radiated from the pipe is minimized.

In addition, the manufacturing method of the present invention is a method for manufacturing a heat-retaining pipe for insulating fluid flowing in a pipeline, in which a giant flat plate is manufactured by drilling pin holes in plywood plywood. A giant electric heating sheet is preformed by sandwiching a heating wire between two thermosetting welded rubber sheets using a mold, and the preformed giant electric heating sheet is made into a straight or bent cylindrical pipe. Apply a bonding agent to it and wrap it around the
A core metal is passed through the cylindrical pipe and heated while being pressurized through synthetic rubber in a sealed mold.
It is characterized in that it is formed into a straight or bent shape along the outer periphery of the cylindrical pipe, and is hardened and molded to have an annular cross section, and at the same time is tightly joined to the outer periphery of the cylindrical pipe.

According to the above configuration, the veneer plywood has a huge standard size of 180 cm in length and 90 cm in width, so by using this veneer plywood, a huge flat type can be easily obtained. Even larger flat molds can be easily and relatively inexpensively manufactured by joining together several pieces of veneer plywood of the same size. In addition, since plywood is made of several thin sheets that are glued together so that they are perpendicular to each other, the positioning pins are held in a flat shape by giving appropriate squeaks, and when force is applied. It stays in the flat mold without sinking or falling out. A thermosetting welding rubber sheet, such as a silicone rubber sheet, is well welded to a heating wire during preforming, and is heat cured in a bonding process to be formed into a desired shape and at the same time tightly bonded to a pipe.

"Example" Hereinafter, an example of the present invention will be specifically described with reference to the drawings.

In FIGS. 1a, b, 2a, b, and 3, the flat plate mold 1 is made by joining two plywood sheets 2 and 3 with a flat metal fitting 4 and wood screws 5. The length L is approximately 360 cm, the width W is approximately 90 cm, and the thickness D is approximately 0.9 cm. A large number of pin holes 1A are bored in the flat plate mold 1, and positioning pins 6 are inserted into each of the pin holes 1A. As shown in FIG. 3, the plywood veneers 2 and 3 in the flat plate type 1 are made by stacking and bonding a large number of thin plates 7, 8, 9, 10, etc. perpendicularly to each other. A thin piece of wood protrudes from the pin hole 1A drilled in 3, and the positioning pin 6 is inserted into the pin hole 1A by the piece of wood.
It is easily held in place, and becomes freely movable when force is applied from the axial direction.

Figures 4a, b, c, d, and e show the preforming method. In the wiring process shown in FIG. 4a, the heating wire 20 is hooked and/or wrapped around the positioning pin 6 inserted into the flat mold 1 for wiring. Figure 4b
In the illustrated bonding transfer process, a silicone raw rubber sheet 21 reinforced with glass cloth is placed on the flat mold 1, and when it is pressed and heated by a hot press (not shown), the positioning pins 6 sink downward into the flat mold 1. The heating wires 20 on the flat mold 1 are bonded and transferred to a raw silicone rubber sheet 21, which is a thermosetting welding rubber sheet, while maintaining the wired shape. Subsequently, in the clamping and bonding step shown in FIG.
1 is turned over, another silicone raw rubber sheet 22 is placed on top of this sheet 21, and the sheet 21 and the sheet 22 are bonded to each other with the heating wire 20 sandwiched therebetween by applying pressure and heating using a hot press. In the terminal connection step shown in FIG. 4d, a soft lead wire 24 such as a Teflon wire made of a large number of wires twisted together is connected to the end of the heating wire 20 via the terminal plate 23. Finally, in the terminal protection step shown in FIG. A sheet 26 can be manufactured. The electric heating sheet 26 manufactured according to this example had a size of 300 cm in length and 40 cm in width. The length of the insulation pipe is approximately 300cm, and the diameter is approximately 12cm.
It was cm.

FIG. 5 shows the mold structure for performing the bonding molding process. A dish-shaped intermediate mold 32 is fitted into the box-shaped lower mold 31, and a plug-shaped upper mold 33 is further fitted into the intermediate mold 32. A flow hole 32a is bored in the lower part of the intermediate mold 32. The synthetic rubber 34 is filled between the intermediate mold 32 and the upper mold 33 at the beginning of the bonding molding process. Since the synthetic rubber 34 is discarded after the bonding and molding process is completed, a poor quality material is used. The lower mold 31 includes a straight pipe 35 as shown in FIG. 6a, a 90° bent pipe 36 as shown in FIG. 6b, or a 45° bent pipe 36 as shown in FIG. 6c. A bent pipe 37 is arranged, and a core metal 3 is attached to these pipes 35, 36, 37.
8 is passed. The core metal 38 is for preventing the pipes 35 to 37 from being crushed by high molding pressure. A binder such as an adhesive or a primer is applied to the pipes 35 to 37, and a preformed electric heating sheet 26 is wrapped around the pipes 35 to 37.

In the above configuration, first the intermediate mold 32 is filled with synthetic rubber 34, and then the upper mold 33 and the lower mold 31 are filled with synthetic rubber 34.
When pressed from above and below with a hot plate of a heat press (not shown), the synthetic rubber 34 is compressed into the upper mold 33 and the intermediate mold 32.
The fluid is pressurized between the fluid holes 32a and gradually flows to fill the lower mold 31. Then, the entire circumference of the electric heating sheet 26 in the lower die 31 is pressed evenly and strongly toward the pipes 35 to 37 by the synthetic rubber 34, and is heated and cured by the heating plate, so that the electric heating sheet 26 is pressed against the pipes 35 to 37 by the synthetic rubber 34. The heat-retaining pipe 40 is formed along the surface shape of the pipes 35 to 37 into a good pipe shape having a straight or bent shape and having a cylindrical cross section and no streaks, and is closely joined to the pipes 35 to 37. can be manufactured. Note that the synthetic rubber 34 is peeled off from the electric heating sheet 26 after being pressurized and heated and discarded. Note that if the diameters, lengths, etc. of the pipes 35 to 37 are standardized, the heat retaining pipe 40 will be even more suitable for factory production.

"Effects" As stated above, the heat insulation pipe of the present invention has
An electric heating sheet consisting of a heating wire sandwiched between thermosetting welded rubber sheets is placed around the outer periphery of a straight or bent cylindrical pipe to follow the outer shape of the cylindrical pipe. A binder was applied and wrapped in an annular cross-sectional shape, and the electrically heated sheet was heated while being pressurized through synthetic rubber in a sealed mold, thereby heating and curing, and at the same time tightly bonding it to the outer periphery of the cylindrical pipe. Therefore, the degree of heat retention can be freely adjusted as desired by the heat generated by the heating wire, and the high temperature and/or high pressure fluid in the pipeline can be satisfactorily heated. /
Another advantageous effect is that the heat-retaining pipe is not damaged by the high-pressure fluid.

In addition, since the manufacturing method of the present invention uses a flat plate made of giant plywood, it is possible to manufacture an electric heating sheet of a huge size suitable for a heat-retaining pipe at a relatively low cost and in good condition. It is possible to quickly and easily change the dimensions of the sheet, and it is also possible to wrap the preformed electric heating sheet around a straight or bent cylindrical pipe with a bonding agent and seal it with a metal sheet. Since the electric heating sheet is heated while being pressurized through synthetic rubber in the mold, it has excellent effects such as the electric heating sheet being molded along the surface of a straight or bent cylindrical pipe and being closely bonded at the same time. There is.

[Brief explanation of the drawing]

1a and b are a plan view and a front view showing a flat plate mold used in an embodiment of the present invention, FIGS. Figure 3 is a cross-sectional view showing the positioning pin inserted into the flat mold, Figures 4 a to e are perspective views showing the preforming method, and Figure 5 is a cross-sectional view showing the mold structure for performing the bonding molding process. Figure 6a,
b and c are front views showing manufactured heat-retaining pipes. 1... Flat plate type, 2, 3... Plywood plywood, 6...
Positioning pin, 20... Heating wire, 21, 22...
Silicone raw rubber sheet, 26... Electric heating sheet, 3
1...Lower mold, 32...Middle mold, 33...Upper mold, 3
4...Synthetic rubber, 35...Straight pipe, 36...
...90° bent pipe, 37...45° bent pipe, 38...core metal, 40...heat insulation pipe.

Claims (1)

[Scope of Claims] 1. In a heat-retaining pipe for keeping fluid flowing in a pipeline warm, an electric heating sheet consisting of a heating wire sandwiched between thermosetting welded rubber sheets can be used in a straight or bent shape. A binder is applied and wrapped around a cylindrical pipe to form a straight or bent shape along the outer periphery of the cylindrical pipe and a circular cross section, and the electric heating sheet is placed in a sealed mold using synthetic rubber. A heat-retaining pipe characterized in that it is heated and hardened by heating while pressurizing through a pipe, and at the same time is closely bonded to the outer periphery of a cylindrical pipe. 2. In a method for manufacturing heat-retaining pipes to insulate fluids flowing in pipelines, pin holes are drilled in plywood plywood to create a giant flat plate mold, and the giant flat plate mold is used to insulate two sheets of heat. A giant electric heating sheet made by sandwiching heating wires between curable welding rubber sheets is preformed, and a binder is applied to the preformed giant electric heating sheet onto a straight or bent cylindrical pipe. The core metal is passed through the cylindrical pipe and heated under pressure through synthetic rubber in a sealed mold to form a straight or bent shape along the outer periphery of the cylindrical pipe and a circular cross-section. A method of manufacturing a heat-retaining pipe, which comprises curing and molding it into an annular shape and at the same time closely joining the outer periphery of the cylindrical pipe.