JPH0338478B2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention is designed to fit into the inner periphery of a pipe that transports a fluid to prevent heat transfer between the fluid and the pipe, or to prevent heat transfer between the fluid and the pipe. This invention relates to a heat-insulating tube that fits around the outer periphery of the pipe and insulates the pipe itself.

<Conventional technology> Conventionally, in order to keep the pipes warm, a heat-retaining insulation material is wrapped around the outer circumference of the pipe, and a waterproof racking cover is placed on the outside of the pipe, or a heat-retaining insulation material is wrapped with aluminum vapor-deposited paper, or waterproof paper is used. There are those that are wrapped with cloth and finished with paint, and those that are wrapped with cloth and have a simple molded material glued to them.

There was also an internal heat-insulating type that fit into the inner circumference of the pipe.

<Problems to be Solved by the Invention> However, in the above-mentioned conventional piping covered with heat-retaining insulation material, incomplete sealing occurs in the lagging cover due to expansion and contraction due to thermal expansion and contraction. In addition to the breathing effect of the insulation material, moisture absorption or water infiltration occurs in the thermal insulation material, which not only significantly reduces the insulation performance, but also accumulates moisture in the thermal insulation layer, increasing the heat capacity and worsening thermal response. There was a problem.

In addition, internal thermal insulation systems that do not have a coating have the problem of fluid entering the thermal insulation material, reducing the insulation performance, increasing the heat capacity of the thermal insulation layer and worsening responsiveness, and the problem of heat retention for the fluid. There were problems such as the mixing of insulation materials.

In addition, in the case of an internal heat-retaining insulation method that uses a heat-retaining heat-insulating layer that is coated with the same type of thick and elastic coating layer on the inside and outside, a temperature difference occurs between the inside and outside of the heat-retaining heat-insulating layer. For this reason, the degree of expansion and contraction of the coating layer differs between the inside and the outside, causing problems such as the coating layer being broken, distorted, or bent, resulting in poor reliability, especially for long-term use.

<Means for Solving the Problems> Therefore, the present invention provides a cylindrical heat-insulating layer to be fitted to the inner or outer periphery of a pipe, the outer and inner surfaces thereof having different thicknesses and flexibility. The present invention provides a heat-insulating and heat-insulating cylinder in which a covering layer made of a leak-proof material is provided, and the cylindrical heat-insulating layer is sealed with the covering layer.

In addition, in the heat-insulating cylinder, a bellows portion may be provided in a part of the thick and hard coating layer.

<Function> According to the present invention, since the cylindrical heat-retaining insulation layer is sealed with a covering layer made of a leak-proof material, there is no possibility that the insulation layer absorbs moisture or water seeps into the insulation layer.
There is no possibility of fluid intrusion, and the material constituting the heat insulating layer will not be mixed into the fluid.

Furthermore, in the present invention, the outer and inner surfaces of the cylindrical heat-retaining and heat-insulating layer are provided with coating layers made of leak-tight materials having different thicknesses and flexibility, so that the inner and outer surfaces of the heat-retaining and heat-insulating layer are Even if a temperature difference occurs on the outside, the two coating layers expand and contract according to this temperature difference, so problems such as the coating layer breaking, distorting, or bending do not occur.

Note that by providing a bellows portion in a part of the thick and hard coating layer to give it flexibility, it is possible to cope with large thermal expansion and contraction of the cylindrical heat-insulating layer.

<Example> In each of the illustrated examples, 1 is a cylindrical heat-insulating layer, 2 and 3 are covering layers made of a leak-tight material that jointly seal the cylindrical heat-insulating layer 1, and the covering layer 2 is a cylindrical heat-insulating layer. Composed of a thin and flexible tube or membrane,
The covering layer 3 is composed of a relatively thick and hard cylinder. The cylindrical thermal insulation layer may be fibrous, granular, foamed granular, ultrafine granular, sintered molded product of silicon oxide, magnesium oxide, calcium oxide, aluminum oxide, or a mixture thereof; If it cannot be used in an oxidizing atmosphere, the gas remaining in the seal can be replaced with nitrogen gas or the like.

In addition, the materials of the leak-tight tube or membrane 2 and cylinder 3 are designed so that they do not chemically interfere with the fluid and the heat-insulating layer, and that their physical strength is maintained under the operating temperature conditions. For example, cross-linked polyethylene is used up to about 110°C, and silicone rubber or Teflon is used at higher temperatures up to about 250°C.

In the heat-insulating cylinder shown in Figs. 1 and 2, the cylindrical heat-insulating layer 1 is made of fine powder of silicon oxide (SiO ₂ ), for example.
A tube of Teflon resin (tetrafluoride resin:
TFE) 3 is fitted, and a flexible Teflon heat-shrinkable tube (FEP-700) is attached to the outer periphery and both end faces of the insulation layer.
2, the tube 2 is heat-shrinked at a temperature of 400°C or higher, and each end of the tube is welded and sealed to each end of the tube 3 to seal the heat-insulating layer 1. The cylinder can be used up to temperatures of ~260°C. This thermal insulation cylinder can be fitted onto the outer periphery of the pipe 4 through which the fluid flows (exterior type thermal insulation implementation) as shown in Fig. 3, and can be used to insulate the pipe 4 itself. As shown in FIG.
It can also be used to insulate and insulate fluid to flow inside the tube 3 itself fitted to the inner periphery of the tube.

The heat-insulating cylinder shown in Fig. 5 is constructed by fitting a Teflon resin cylinder 3 onto the outer periphery of the cylindrical heat-insulating layer 1, in contrast to the ones shown in Figs. The tube is covered with a heat-shrinkable tube 2, which is heat-shrinked at a high temperature, and both ends are welded and sealed to each end of the tube 3 to seal the heat-insulating layer. This heat-retaining insulation cylinder is suitable for external insulation implementation in which a pipe 4 through which fluid flows is passed through the inner periphery.

The reason why the embodiment shown in FIG. 6 is different from that shown in FIG. A bellows portion 6 is provided at the portion, and this bellows portion provides flexibility.

In the embodiment shown in FIG. 7, the cylinder 3 fitted to the inner periphery of the cylindrical heat insulating layer 1 is not very flexible, so a bellows part 6 is similarly provided in a part of the cylinder 3 to give it flexibility. The rest of the structure is the same as the embodiment shown in FIGS. 1 and 2.

In the case of the embodiments shown in FIGS. 6 and 7 described above, the cylinder 3
Since it is made flexible by the bellows part 6, it can cope with large thermal expansion and contraction of the cylindrical heat-insulating layer 1.

<Effects of the Invention> According to the present invention, since the cylindrical heat-insulating layer is sealed with a leak-proof material, a highly reliable heat-insulating cylinder that maintains the initial heat-insulating performance over a long period of time can be provided. It is possible to economically implement piping with both superior internal and external thermal insulation methods.

[Brief explanation of drawings]

Fig. 1 is an axial cross-sectional view of a first embodiment of the heat-insulating cylinder according to the present invention, Fig. 2 is a cross-sectional view taken along the - line in Fig. 1, and Fig. 3 is an exterior type of the heat-insulating cylinder of Fig. 1. FIG. 4 is an axial sectional view of a state in which internal heat insulation is applied; FIG. 5 is an axial sectional view of a second embodiment of the heat insulating tube according to the present invention; FIG. 6 is an axial sectional view of the third embodiment, and FIG. 7 is an axial sectional view of another embodiment. In the figure, 1 indicates a cylindrical heat-insulating layer, and 2 and 3 indicate tubes made of leak-proof material.

Claims (1)

[Claims] 1. The outer and inner surfaces of the cylindrical heat-insulating layer to be fitted to the inner or outer circumference of the pipe are made of leak-tight materials with different thicknesses and flexibility, respectively. 1. A heat-retaining and heat-insulating cylinder, characterized in that a covering layer is provided, and the cylindrical heat-retaining and heat-insulating layer is sealed with the covering layer. 2. The heat-retaining and insulating cylinder according to claim 1, wherein a bellows portion is provided in a part of the thick and hard coating layer in the heat-retaining and insulating cylinder.