JP2010002016A - Heat insulating structure and its repair method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat insulating structure for effectively maintaining the heat insulating property. <P>SOLUTION: The heat insulating structure includes: a material 10 to be thermally insulated; a first heat-insulating member 20, which covers the material 10; and a second heat-insulating member 30, which covers the first heat-insulating member 20 having both steam permeability and water impermeability. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a heat retaining structure, and more particularly to maintaining heat insulation in a heat retaining structure.

Conventionally, for example, Patent Document 1 describes that an outer periphery of a pipe is covered with a heat insulating material, and further, an outer periphery of the heat insulating material is covered with a protective cover made of a metal plate.
JP-A-8-19830

  However, in the above prior art, for example, when water enters from the joint of the protective cover due to rain, the heat insulating material contains water, and as a result, the heat insulating property of the heat insulating material may be lowered. In this case, it is necessary to replace the heat insulating material containing water with a new dry heat insulating material.

  This invention is made | formed in view of the said subject, Comprising: It aims at providing the heat retention structure which can maintain heat insulation effectively.

  In order to solve the above problems, a heat retaining structure according to an embodiment of the present invention includes a heat retaining body, a first heat retaining material that covers the heat retaining body, and a water vapor permeability that covers the first heat retaining material. And a second heat insulating material having non-water permeability. ADVANTAGE OF THE INVENTION According to this invention, the heat retention structure which can maintain heat insulation effectively can be provided.

  Further, the heat retaining body is a pipe through which a fluid flows, the first heat insulating material covers an outer periphery of the pipe, and the second heat insulating material covers an outer periphery of the first heat insulating material. It may be covered. If it carries out like this, the piping structure which can maintain heat insulation effectively can be provided. The second heat insulating material may be a fibrous body filled with aerogel. If it carries out like this, the heat insulation of a heat retention structure can be maintained more effectively.

  Hereinafter, a heat retaining structure (hereinafter referred to as “the present structure”) according to an embodiment of the present invention will be described. In the present embodiment, an example in which the present structure is a pipe structure having a pipe as a heat retaining body, which is a structure to be kept warm, will be mainly described.

  FIG. 1 is a perspective view of an example of the structure 1, and FIG. 2 is a cross-sectional view of the structure 1. As shown in FIGS. 1 and 2, the structure 1 includes a pipe 10 through which a fluid flows, a first heat insulating material 20 that covers the outer periphery of the pipe 10, and an outer periphery of the first heat insulating material 20. And a second heat insulating material 30 to be covered. In FIG. 1, for convenience of explanation, a part of the first heat insulating material 20 and the second heat insulating material 30 covering the outer periphery of the pipe 10 is omitted, and the pipe 10 and the first heat insulating material are omitted. 20 and the second heat insulating material 30 are respectively exposed.

  The pipe 10 is installed to transport a liquid or gas having a temperature higher than the outside air temperature of the environment where the present structure 1 is arranged. The pipe 10 is made of a metal such as carbon steel or stainless steel, for example. In the hollow portion 10a formed inside the pipe 10, a liquid or gas to be transported flows.

  The first heat insulating material 20 is a heat insulating material provided to suppress cooling of the pipe 10 by the outside air. The heat insulating material that can be used as the first heat insulating material 20 is not particularly limited as long as it is a member having an appropriate heat insulating property according to the purpose. For example, calcium silicate (zonolite calcium silicate, etc.), perlite, and the like. It is possible to preferably use a heat insulating inorganic porous body such as glass wool, rock wool or the like. Moreover, as the 1st heat insulating material 20, what was formed as a cylindrical molded object which can be divided | segmented into plurality in the circumferential direction prior to construction to the piping 10, for example can also be used.

  Moreover, as the 1st heat insulating material 20, the heat insulating inorganic porous molded object or the inorganic fiber body in which the process which raises the water repellency was given can be used. However, such a water repellent treatment cannot impart water permeability to the first heat insulating material 20, and the first heat insulating material 20 has water permeability.

  The 2nd heat insulating material 30 is equipped with heat insulation, water vapor permeability, and water impermeability. That is, the second heat insulating material 30 has a heat insulating property capable of increasing the temperature inside the first heat insulating material 20.

  Specifically, in the first heat insulating material 20, the surface on the opposite side (shown in FIG. 2) is compared with the temperature of the surface on the pipe 10 side (inner surface 21 on the radially inner side of the pipe 10 shown in FIG. 2). The temperature of the outer surface 22) on the radially outer side of the pipe 10 is lowered. In this regard, by covering the outer periphery (that is, the outer surface 22) of the first heat insulating material 20 with the second heat insulating material 30, the first heat insulating material 20 is compared with the case where the second heat insulating material 30 is not covered. The temperature of the outer surface 22 can be increased. As a result, in the first heat insulating material 20, the difference between the temperature in the vicinity of the outer surface 22 and the temperature in the vicinity of the inner surface 21 is reduced, and the temperature can be increased in the entire area inside the first heat insulating material 20.

  The second heat insulating material 30 also has water vapor permeability that allows water vapor (that is, gaseous water) generated in the first heat insulating material 20 to pass therethrough. Furthermore, the second heat insulating material 30 also has a water-impermeable property through which liquid water cannot permeate even when exposed to strong rain or wind.

  As the second heat insulating material 30, a heat insulating material having both water vapor permeability and non-water permeability can be used. For example, a fiber body filled with aerogel (hereinafter referred to as “aerogel fiber body”) is preferable. Can be used.

  This airgel fiber body is a heat insulating structure that can be manufactured by filling a fiber substrate with airgel. Specifically, the airgel fiber body can be produced, for example, by impregnating a fiber tube of a fiber base material with an airgel raw material and then supercritically drying the fiber base material impregnated with the airgel raw material. .

  As a fiber base material which comprises an airgel fiber body, the woven fabric or nonwoven fabric of an inorganic fiber or an organic fiber can be used. By using a nonwoven fabric in which fibers are entangled irregularly as a fiber base material, the airgel can be more effectively held between the fibers.

  Moreover, as a fiber which comprises a fiber base material, ceramic fibers, such as resin fibers, such as a polyethylene terephthalate (PET) fiber, carbon fiber, glass fiber, an alumina fiber, can be used, for example.

  As an airgel with which a fiber base material is filled, an airgel (inorganic airgel) made of an inorganic material or an airgel (organic airgel) made of an organic material can be used. By using the inorganic airgel, the heat resistance of the airgel fiber can be effectively increased.

  As the inorganic airgel, for example, silica airgel or alumina airgel can be used. Especially, the heat insulation of an airgel fiber body can be effectively improved by using a silica airgel.

  Moreover, as the second heat insulating material 30, a material having higher heat insulation than the first heat insulating material 20 can be preferably used. That is, for example, the second heat insulating material 30 whose heat conductivity is lower than the heat conductivity of the first heat insulating material 20 can be preferably used.

  Specifically, the thermal conductivity at 25 ° C. of the second heat insulating material 30 measured by a method according to ASTM C177 is preferably 0.05 W / (m · K) or less, for example, 0.02 W. / (M · K) or less is more preferable.

  That is, for example, an airgel fiber body whose thermal conductivity is in the above range can be preferably used as the second heat insulating material 30. In addition, the airgel which fills the space | gap between the fibers of an airgel fiber body can prevent effectively the convection of the air in the inside of the said airgel fiber body by the micropore in the said airgel. For this reason, an airgel fiber body can have the outstanding heat insulation.

In addition, the water vapor permeability of the second heat insulating material 30 measured by a method based on ASTM E96 (Procedure B) is preferably, for example, 600 ng / (Pa · S · m ² ) or more, preferably 1500 ng / ( Pa · S · m ² ) or more is more preferable.

  Moreover, the water absorption rate after immersion in water of the second heat insulating material 30 measured by a method based on ASTM C1104 is, for example, preferably 10% by weight or less, and more preferably 4% by weight or less. Further, the water repellency of the second heat insulating material 30 measured by a method based on ASTM C1511 is, for example, preferably 5 g weight loss or less, and more preferably 3 g weight loss or less.

  That is, as the second heat insulating material 30, for example, an airgel fiber body further provided with both or one of water absorption and water repellency in the above range in addition to the water vapor permeability in the above range can be preferably used. . In addition, the airgel fiber body can have the above water vapor permeability and water impermeability in addition to the excellent heat insulating property due to the fine pores in the airgel as described above.

Moreover, when using an airgel fiber body as the 2nd heat insulating material 30, it is preferable that the bulk density of the said airgel fiber body shall be the range of 100-300 kg / m < ³ >, for example, and the range of 150-200 kg / m < ³ > More preferably. By using an airgel fiber body having a bulk density in the above range, the structure 1 can be reduced in weight.

  Moreover, it is preferable that the 2nd heat insulating material 30 has moderate flexibility. That is, as the second heat insulating material 30, a sheet-like body having flexibility that can be wound around the outer periphery of the first heat insulating material 20 can be used.

  Specifically, for example, an airgel fiber sheet obtained by filling a fiber base material, which is a nonwoven fabric, with airgel can be preferably used. In this case, the thickness of the airgel fiber body is, for example, preferably in the range of 2 to 20 mm, and more preferably in the range of 3 to 10 mm.

  In the present structure 1, the heat insulating property can be effectively maintained. That is, for example, when the first heat insulating material 20 is a heat insulating inorganic porous molded body or an inorganic fiber body as described above, when water enters the first heat insulating material 20 from the outside of the structure 1, The 1st heat insulating material 20 hold | maintains water, As a result, the heat insulation of the said 1st heat insulating material 20 will fall.

  On the other hand, in the present structure 1, the second heat insulating material 30 constituting the outermost layer has water-impermeable properties. For example, even when the present structure 1 is exposed to rain or snow, It is possible to effectively prevent water from entering the structure 1 and including water in the first heat insulating material 20.

  Therefore, by covering the first heat insulating material 20 with the second heat insulating material 30, the heat insulating property of the first heat insulating material 20 can be effectively maintained. Of course, since the 2nd heat insulating material 20 itself is water-impermeable, it can maintain the heat insulation effectively.

  Moreover, in this structure 1, even if it is a case where the heat insulation of the 1st heat insulating material 20 falls, the heat insulation can be recovered effectively. That is, for example, when the structure 1 is manufactured by winding the sheet-like second heat insulating material 30 around the outer periphery of the first heat insulating material 20, a seam ( (Not shown) will be formed.

  In this case, when rain or snow is strongly blown against the structure 1, water flows between the second heat insulating material 30 and the first heat insulating material 20 from the gap between the seams of the second heat insulating material 30. It may enter and the first heat insulating material 20 may contain water.

  However, in this structure 1, water can be effectively discharged from the first heat insulating material 20. That is, as described above, in the present structure 1, since the first heat insulating material 20 is covered by the second heat insulating material 30, the temperature inside the first heat insulating material 20 is changed from the inner surface 21 to the outer surface 22. The entire range up to can be maintained in a range close to the temperature of the pipe 10. Accordingly, when water enters the first heat insulating material 20, the water can be effectively evaporated inside the first heat insulating material 20.

  And since the 2nd heat insulating material 30 which covers the 1st heat insulating material 20 has the water vapor permeability which the vaporized water can permeate | transmit, it generate | occur | produces by evaporation of the water contained in the 1st heat insulating material 20 The water vapor that has passed through the second heat insulating material 30 is effectively discharged outside the structure 1. That is, the water vapor generated inside the first heat insulating material 20 is supplied from the surface of the second heat insulating material 30 on the first heat insulating material 20 side (the inner surface 31 shown in FIG. 2) to the second heat insulating material 30. The surface exposed to the outside air (outer surface 32 shown in FIG. 2) passes through the inside of the second heat insulating material 30 and is discharged into the outside air.

  Thus, in this structure 1, since the 1st heat insulating material 20 is covered with the 2nd heat insulating material 30 provided with heat insulation, water vapor permeability, and water permeability, the said 1st heat insulating material 20 is concerned. It is possible to evaporate the water that has entered the air and to discharge the water through the second heat insulating material 30 to dry the first heat insulating material 20 again. That is, the structure 1 has a heat-insulating self-healing ability.

  Moreover, in this structure 1, it is good also as covering the outer periphery of the 2nd heat insulating material 30 with a metal exterior material further. FIG. 3 is a perspective view of an example of the main structure 1 in this case, and FIG. 4 is a cross-sectional view of the main structure 1.

  In the example shown in FIGS. 3 and 4, the structure 1 is made of metal that covers the outer periphery of the second heat insulating material 30 in addition to the pipe 10, the first heat insulating material 20, and the second heat insulating material 30. The exterior material 40 is included.

  Therefore, in this structure 1, since the first heat insulating material 20 is covered with the second heat insulating material 30 and the exterior material 40, it is more effective that water enters the first heat insulating material 20 from the outside. Can be prevented.

  Moreover, this structure 1 can improve the mechanical strength by having the metal exterior member 40 as the outermost layer. For this reason, for example, an operator can get on the structure 1 (that is, on the exterior material 40) and perform a predetermined work.

  Next, specific examples will be described.

[Example]
In this example, the heat-insulating self-healing ability in the structure 1 shown in FIGS. 3 and 4 was confirmed. That is, the piping 10 for transporting warm water was prepared as a body to be insulated. The pipe 10 is a carbon steel cylindrical structure having an outer diameter of about 200 mm, and is installed outdoors so as to extend substantially horizontally.

  Moreover, the cylindrical heat-insulating inorganic porous molded object which has calcium silicate as a main component as the 1st heat insulating material 20 was prepared. This new heat insulating material had a thickness of 40 mm and could be divided into four in the circumferential direction.

  Further, as the second heat insulating material 30, an airgel fiber body (Pyrogel 6350, Aspen Aerogels Inc.) in which a fiber base material that is a nonwoven fabric of mixed fibers containing carbon fibers and glass fibers is filled with silica-based airgel is used. . This airgel fiber body was a sheet-like molded body having a thickness of 6 mm and having appropriate flexibility. Moreover, as the exterior material 40, a cylindrical cover material made of a colored galvanized steel sheet having a thickness of 0.4 mm was prepared.

  In the first condition, first, each part of the first heat insulating material 20 divided into four parts was immersed in water all day and night in a resin bag. Subsequently, the 1st heat insulating material 20 containing water was taken out from the container by immersion, and the said 1st heat insulating material 20 was attached so that the outer periphery of the piping 10 might be covered.

  And the 2nd heat insulating material 30 was attached so that the outer periphery of the 1st heat insulating material 20 containing this water might be covered, and this structure 1 as shown in FIG.1 and FIG.2 was manufactured. Furthermore, the exterior material 40 was attached so that the outer periphery of the 2nd heat insulating material 30 might be covered, and this structure 1 as shown in FIG.3 and FIG.4 was manufactured.

  Thus, a piping structure (structure 1) having the piping 10, the first heat insulating material 20 containing water by the dipping process, the second heat insulating material 30 made of the airgel fiber body, and the metal exterior material 40. ) Was manufactured.

  In the second condition, similar to the first condition described above, the first heat insulating material 20 was immersed in water, and the first heat insulating material 20 containing water was attached to the pipe 10. The outer periphery of the first heat insulating material 20 was covered with the exterior material 40 without attaching the second heat insulating material 30. Thus, a piping structure (Structure 2) having the piping 10, the first heat insulating material 20 containing water by the dipping treatment, and the metal exterior material 40 was manufactured.

  Under the third condition, the dried first heat insulating material 20 not immersed in water was attached so as to cover the outer periphery of the pipe 10. And the exterior material 40 was attached so that the outer periphery of this 1st heat insulating material 20 might be covered. Thus, a piping structure (structure 3) having the piping 10, the dried first heat insulating material 20, and the metal exterior material 40 was manufactured.

  In this way, three types of structures 1 to 3 were manufactured outdoors. And the water whose temperature is the range of 61.5 degreeC-65.8 degreeC was distribute | circulated in the piping 10 of each structure 1-3. Furthermore, for each of the structures 1 to 3 used for transporting hot water, the temperature of the outer surface of the outer packaging material 40 that is the outermost layer and the moisture contained in the first heat insulating material 20 covered by the outer packaging material 40 The change with time was measured.

  That is, the surface temperature and the amount of water were measured at the timing when 12 days had elapsed since the construction of structures 1 to 3 and when 45 days had elapsed. Moreover, the surface temperature and the amount of moisture were measured by bringing a measuring instrument into contact with each of the upper surface and the lower surface of the exterior member 40 in the vertical direction among the structures 1 to 3 extending in the horizontal direction. The amount of moisture was measured with a neutron moisture meter (MCM-2 type, manufactured by CPN).

  FIG. 5 shows the results measured on the 12th day, and FIG. 6 shows the results measured on the 45th day. In FIG.5 and FIG.6, about each of the structures 1-3, whether the 1st heat insulating material 20 was subjected to the immersion process which contains water, the said 1st heat insulating material 20 with the 2nd heat insulating material 30 is shown. The condition of whether or not it was covered, the surface temperature (° C.) measured at each of the upper part and the lower part of the exterior material 40, and the moisture measured at each of the upper part and the lower part of the exterior material 40 The quantity (measured value) is shown.

  In addition, the moisture content shown in FIG.5 and FIG.6 is the numerical value measured with the neutron moisture meter. As the amount of moisture contained in the first heat insulating material 20 increases, the measured value by the neutron moisture meter also increases. Further, the temperature at the time of measurement on the 12th day was 13 ° C. and the humidity was 42%, and the temperature at the time of measurement on the 45th day was 10 ° C. and the humidity was 66%.

  As shown in FIG. 5, at the time of the twelfth day, in any of the structures 1 to 3, the upper surface temperature was higher than the lower portion, and the upper moisture content was higher than the lower portion. This is considered to be because water contained in the heat insulating material is accumulated on the lower side due to the action of gravity in any of the structures 1 to 3.

  Further, the surface temperature of the structure 1 manufactured by coating the first heat insulating material 20 containing water by the immersion treatment with the second heat insulating material 30 is the same as that of the first heat insulating material 20 containing water. It was lower than that of the structure 2 constructed without covering with the heat insulating material 30 and was similar to that of the structure 3 having the first heat insulating material 20 not subjected to the immersion treatment.

  As described above, the heat insulating property of the structure 1 in which the first heat insulating material 20 is covered with the second heat insulating material 30 is that of the structure 2 in which the first heat insulating material 20 is not covered with the second heat insulating material 30. It was confirmed that it was higher than that.

  In addition, the water content of Structure 1 was significantly lower than that of Structure 2. That is, in the structure 1 in which the first heat insulating material 20 is covered with the second heat insulating material 30, the first heat insulating material 20 has a moisture content as compared with the structure 2 in which the first heat insulating material 20 is not covered with the second heat insulating material 30. It was confirmed that the discharge (i.e., drying) was more advanced.

  Furthermore, as shown in FIG. 6, on the 45th day, the surface temperature of the structure 1 having the second heat insulating material 30 is approximately the same as that of the structure 3 in which the first heat insulating material 20 is not subjected to the immersion treatment. It was. Further, in the structure 1, the surface temperature on the upper surface side and the surface temperature on the lower surface side almost coincided. Furthermore, the moisture content of structure 1 was almost identical to that of structure 3.

  On the other hand, the surface temperature of the structure 2 without the second heat insulating material 30 was higher than that of the structure 3 in which the first heat insulating material 20 was not subjected to the immersion treatment. In structure 2, the surface temperature on the lower surface side was higher than the surface temperature on the upper surface side. Furthermore, the moisture content of structure 2 was higher than that of structure 3.

  Thus, in the structure 1 manufactured by covering the first heat insulating material 20 with the second heat insulating material 30, moisture can be substantially completely discharged from the first heat insulating material 20. As a result, the heat insulating property of the first heat insulating material 20 could be recovered almost completely.

  Note that the present invention is not limited to this embodiment. That is, the heat retaining structure according to the present invention is not limited to the piping structure as described above. For example, a body part and a mirror part of existing horizontal or vertical equipment covered with a heat insulating material can also be repaired by this method.

It is a perspective view about an example of the heat retention structure concerning one embodiment of the present invention. It is sectional drawing of the heat retention structure shown in FIG. It is a perspective view about the other example of the heat retention structure which concerns on one Embodiment of this invention. It is sectional drawing of the heat retention structure shown in FIG. In one Embodiment of this invention, it is explanatory drawing which shows an example of the result of having measured the surface temperature and moisture content of the heat retention structure. In one Embodiment of this invention, it is explanatory drawing which shows the other example of the result of having measured the surface temperature and moisture content of the heat retention structure.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Thermal insulation structure, 10 piping, 10a hollow part, 20 1st thermal insulation material, 21 inner surface of 1st thermal insulation material, 22 outer surface of 1st thermal insulation material, 30 2nd thermal insulation material, 31 2nd thermal insulation material Inner surface, 32 Outer surface of second heat insulating material, 40 exterior material.

Claims (3)

A body to be insulated,
A first heat insulating material covering the heat insulating body;
A second heat insulating material that covers the first heat insulating material and has both water vapor permeability and non-water permeability;
A heat insulating structure characterized by having. The insulated body is a pipe through which a fluid flows,
The first heat insulating material covers the outer periphery of the pipe,
The heat insulating structure according to claim 1, wherein the second heat insulating material covers an outer periphery of the first heat insulating material. The heat insulating structure according to claim 1 or 2, wherein the second heat insulating material is a fibrous body filled with airgel.

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