Heat insulating lid

Abstract

To provide a heat insulating lid that can prevent steam leakage from a gap between a heating tank and a lid and obtaining high heat insulation performance to further reduce heat radiation loss.SOLUTION: A heat insulating lid 100 according to the present invention is configured as a heat insulating lid 100 that covers an opening of a heating tank with a top open, and includes a plate material 110 that is placed on a side wall 14 of the heating tank 10, a core material 120 that is arranged under the plate material 110 and fitted into the side wall of the heating tank, and a vacuum film 130 that encapsulates the plate material 110 and the core material 120. The core material 120 is made of an open-cell foam. The vacuum film is larger in dimension than the plate material. The vacuum film 130 is vacuumed in a state of laminating the plate material 110 and the core material 120 thereon to integrate them, so that a hem 132 of the vacuum film 130 is formed on the outer periphery of the plate material 110, and the hem 132 can be folded between the plate material 110 and the side wall 14 of the heating tank 10.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a heat-insulating lid for covering an opening of a heating tank having an open top. [Background technology]

[0002] Factories and other facilities are sometimes equipped with heating tanks that store high-temperature liquids (such as hot water). In order to increase the heating efficiency of the heating tank, it is necessary to suppress the temperature drop between the end of the previous day's work and the start of the next morning's work, in other words, to reduce heat radiation loss. When the heat radiation loss of the heating tank was measured and analyzed, it was found that heat radiation loss (natural convection and radiation) from the tank walls and piping etc. accounted for about 20%, while heat radiation loss due to steam leakage (diffusion of the latent heat of evaporation of water) accounted for 80%, which was greater than the heat radiation from the tank walls and piping.

[0003] In order to reduce the heat radiation loss caused by steam leakage, it is effective to cover the opening of the heating tank with a lid. For example, the vacuum insulation material-containing bathtub lid disclosed in Patent Document 1 can be used as the lid. The vacuum insulation material-containing bathtub lid of Patent Document 1 is characterized in that it "includes a plate-shaped vacuum insulation material, a thermoplastic resin foam sheet bonded to both main surfaces of the vacuum insulation material, and a reinforcing plate bonded to the outer surface side of the thermoplastic resin foam sheet, and the vacuum insulation material side of the thermoplastic resin foam sheet is thermoformed according to the unevenness of the surface of the vacuum insulation material." [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2006-207713 A Summary of the Invention [Problem to be solved by the invention]

[0005] According to the vacuum insulation material-containing bathtub cover of Patent Document 1, since most of the opening of the heating tank can be covered, it is considered that the heat radiation loss caused by steam leakage can be reduced to some extent. However, if the bathtub cover is simply rectangular like the one in Patent Document 1, if the cover floats due to steam, a gap will be created between the cover and the heating tank, or if multiple covers are used, gaps will be created between the covers. Then, steam will leak from the gap. In addition, in order to reduce heat radiation loss, not only the gap but also the insulation performance of the cover itself is important, so further improvement of insulation performance was also required.

[0006] In view of these problems, the present invention aims to provide an insulated lid that can prevent steam leakage from the gap between the heating tank and the lid and achieve higher insulation performance, thereby further reducing heat loss. [Means for solving the problem]

[0007] In order to solve the above problems, a typical configuration of an insulating lid according to the present invention is an insulating lid that covers the opening of a heating tank having an open top, and includes a plate material that rests on the side wall of the heating tank, a core material that is placed under the plate material and fits inside the side wall of the heating tank, and a vacuum film that encapsulates the plate material and the core material, wherein the core material is made of an open-cell foam and the vacuum film is larger in dimensions than the plate material, and the plate material and the core material are stacked on top of each other and the vacuum film is vacuum-drawn to integrate them, thereby forming a hem of the vacuum film around the outer periphery of the plate material, and the hem can be folded between the plate material and the side wall of the heating tank.

[0008] The heating tank may further include a rod-shaped support member that is disposed above the plate member and is enclosed in the vacuum film to function as a handle, the support member having a length that spans a pair of opposing side walls of the heating tank. Effect of the Invention

[0009] According to the present invention, an insulated lid can be provided that can prevent steam leakage from the gap between the heating tank and the lid and achieve higher insulation performance, thereby further reducing heat radiation loss. [Brief description of the drawings]

[0010] [Figure 1] FIG. 2 is an external perspective view of the insulating lid of the present embodiment. [Diagram 2] FIG. 2 is a diagram showing how the insulating lid of this embodiment is used. [Diagram 3] FIG. 2 is a diagram showing how the insulating lid of this embodiment is used. [Figure 4] 10A and 10B are diagrams illustrating the effect of reducing heat radiation loss by the insulating lid of this embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] A preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings. The dimensions, materials, and other specific values ​​shown in the embodiment are merely examples for facilitating understanding of the invention, and do not limit the present invention unless otherwise specified. In this specification and drawings, elements having substantially the same functions and configurations are given the same reference numerals to avoid repeated explanations, and elements not directly related to the present invention are not shown.

[0012] Fig. 1 is an external perspective view of the insulated lid 100 of this embodiment. Fig. 1(a) shows the insulated lid 100 observed from above, and Fig. 1(b) shows the insulated lid 100 observed from below. Figs. 2 and 3 are views of the insulated lid 100 of this embodiment in use. Fig. 2 illustrates a schematic cross section when the insulated lid 100 is attached to the heating tank 10. Figs. 3(a) and 3(b) illustrate the steps for attaching the insulated lid 100 to the heating tank 10.

[0013] As shown in Figures 2 and 3(a), the heating tank 10 has an opening 12 on the upper surface and stores a high-temperature liquid (e.g., hot water 10a) inside. The insulating lid 100 of this embodiment is placed on the side wall 14 of the heating tank 10 and covers the opening 12. As shown in Figures 1 and 2, the insulating lid 100 of this embodiment is composed of a plate material 110, a core material 120, a vacuum film 130, and a support material 140.

[0014] The plate material 110 is a member disposed above the core material 120 and holds the core material 120. The plate material 110 is sized to rest on the side wall 14 of the heating tank 10, and the core material 120 is sized to be inserted into the side wall 14. Therefore, the plate material 110 is designed to have a larger dimension in a plan view than the core material 120. As shown in FIG. 2, when the insulating lid 100 is disposed on the opening 12 of the heating tank 10, the plate material 110 rests on the side wall 14 of the heating tank 10.

[0015] An aluminum composite plate, for example, can be used as the plate material 110. The aluminum composite plate has a structure in which foamed resin is sandwiched between thin aluminum plates, and is suitable as the plate material 110 because it is lightweight yet has appropriate rigidity and excellent weather resistance. In addition, the aluminum composite plate has excellent workability, so it can be easily cut with a blade, and can be easily processed according to the dimensions of the opening 12 of the heating tank 10. Note that the aluminum composite plate is merely an example, and other known materials may be used as the plate material 110.

[0016] The core material 120 is a member that is disposed under the plate material 110 and provides thermal insulation between the inside and outside of the heating tank 10. When the insulating lid 100 is disposed on the opening 12 of the heating tank 10 as shown in Fig. 2, the core material 120 is fitted inside the side wall 14 of the heating tank 10. As the core material 120, an open-cell foam such as urethane foam can be suitably used.

[0017] The vacuum film 130 is a member that encloses and seals the plate material 110, the core material 120, and the support material 140. The vacuum film 130 is designed to have dimensions larger than the plate material 110 in a plan view. A multilayer film can be suitably used as the vacuum film 130. An example of the multilayer film is a multilayer film in which, from the outer layer side, polybutylene terephthalate (PBT), nylon, and polyethylene are laminated.

[0018] Polybutylene terephthalate (PBT) has excellent chemical resistance and can effectively prevent damage when the liquid stored in the heating tank 10 is a chemical. Nylon has excellent gas barrier properties and can prevent erosion of the core material 120 due to corrosive gases. Polyethylene has excellent moisture resistance and can prevent swelling of the vacuum film 130 due to steam and suppress hydrolysis of the core material 120. Note that these materials are merely examples, and a multilayer film made of other known materials may be used as the vacuum film 130, or a single layer film may be used as the vacuum film 130.

[0019] The support material 140 is a rod-shaped member disposed above the plate material 110 and enclosed in the vacuum film 130 together with the plate material 110 and the core material 120. The support material 140 has a length that spans the pair of opposing side walls 14a, 14b of the heating tank 10. The support material 140 functions as a beam that spans the pair of side walls 14a, 14b of the heating tank 10, and supports the load of the plate material 110 and the core material 120. This makes it possible to prevent bending of the core material 120 and the plate material 110 due to thermal deformation or thermal expansion, and to favorably maintain their shapes.

[0020] An example of the support material 140 is an aluminum I-shaped bar. This allows the support material 140 to function as a handle for the insulated lid 100, making it possible to lift the insulated lid 100 easily even if it is heavy. In addition, compared to the conventional case in which the entire periphery of the plate material 110 is reinforced by a frame, it is possible to reduce the weight and reduce the number of steam leakage points. However, the aluminum I-shaped bar is merely an example, and other known materials can also be used for the support material 140.

[0021] As a feature of this embodiment, the insulating cover 100 is integrated by evacuating the vacuum film 130 while the plate material 110, the core material 120, and the support material 140 are stacked. By evacuating, the air inside the bubbles of the core material 120 is removed, and the amount of remaining gas is reduced. This makes it possible to suppress heat transfer due to gas flow inside the core material 120 and obtain higher insulating performance.

[0022] When a vacuum is not applied, the closed-cell foam has higher heat insulating performance than the open-cell foam. In contrast, when a vacuum is applied as described above, the open-cell foam has open cells, so that it can suck gas more efficiently than the closed-cell foam, whose cells are closed. Therefore, when a vacuum is applied, the use of an open-cell foam as the core material 120 provides higher heat insulating performance than the use of a closed-cell foam.

[0023] As described above, the dimensions of the vacuum film 130 in a plan view are designed to be larger than the plate material 110, so that when a vacuum is drawn, a hem 132 of the vacuum film 130 is formed on the outer periphery of the plate material 110. This makes it possible to fold the hem 132 between the plate material 110 and the side wall 14 of the heating tank 10, as shown in Fig. 2. With this configuration, when the hot water in the heating tank 10 turns into steam and flows upward, the folded-back hem 132 functions as a check valve, making it possible to effectively prevent steam from leaking from the heating tank 10.

[0024] As shown in FIG. 3(a), in the insulated lid 100 of this embodiment, the core material 120 has a width that matches the distance between the pair of side walls 14a, 14b, and the plate material 110 has an edge 112 that is located outside the core material 120. As a result, when the core material 120 is fitted between the pair of side walls 14a, 14b, the edge 112 of the plate material 110 is placed on the side walls 14, 14a, 14b of the heating tank. The support material is also placed across the side walls 14a, 14b. By fitting the core material 120 into the side walls 14a, 14b of the heating tank 10 in this way, the gap between the heating tank 10 and the insulated lid 100 is reduced, and steam leakage can be suitably prevented.

[0025] Also, as shown in FIG. 3(b), when the opening 12 (see FIG. 2) of the heating tank 10 is covered with a plurality of insulating lids 100a, 100b, and 100c, the edge 112 of the plate material 110 of the insulating lid 100b is placed on the plate material 110 of the insulating lid 100a, and the edge 112 of the plate material 110 of the insulating lid 100c is placed on the plate material 110 of the insulating lid 100b. This allows the plurality of insulating lids 100a-100c to come into close contact with each other, increasing the contact area, thereby preventing the occurrence of gaps. Therefore, it is possible to prevent steam leakage due to gaps when a plurality of lids 100a and 100b are used.

[0026] Fig. 4 is a diagram illustrating the effect of reducing heat radiation loss by the insulated lid 100 of this embodiment. In Fig. 4, series 1 is the value of heat radiation loss when the insulated lid 100 of this embodiment is used. Series 2 is the value of heat radiation loss when no lid is used. Series 3 is the value of heat radiation loss when a lid made of only a composite aluminum plate is used as a comparative example.

[0027] As shown in Figure 4, in series 2 where no lid was used, the heat radiation loss value rose sharply from the start of the test (0 hours), and the heat radiation loss value after 12 hours was approximately 40 MJ. In contrast, in series 3 where the comparative example lid (composite aluminum plate) was used, the heat radiation loss value rose in a gentle curve from the start of the test, and the heat radiation loss value after 12 hours was approximately 24 MJ. From these results, it can be seen that even with a lid made only of composite aluminum plate, heat radiation loss can be significantly reduced compared to when no lid is used.

[0028] In series 1, when the insulated lid 100 of this embodiment was used, the value of the heat radiation loss increased linearly with a gentle slope from the start of the test, and the value of the heat radiation loss after 12 hours was about 12 MJ. Therefore, by using the insulated lid 100 of this embodiment, the heat radiation loss can be reduced by about 70% compared to when no lid is used, and the heat radiation loss can be reduced by about 50% compared to when a lid made of a composite aluminum plate is used. Therefore, it can be understood that the insulated lid 100 of this embodiment can dramatically reduce the heat radiation loss of the heating tank 10.

[0029] Although the preferred embodiment of the present invention has been described above with reference to the accompanying drawings, it goes without saying that the present invention is not limited to the above-described embodiment. It is clear that a person skilled in the art can think of various modifications or alterations within the scope of the claims, and it is understood that these also naturally belong to the technical scope of the present invention. [Industrial Applicability]

[0030] The present invention can be used as a heat insulating lid for covering the opening of a heating tank having an open top. [Explanation of symbols]

[0031] 10...heating tank, 10a...hot water, 12...opening, 14...side wall, 14a...side wall, 14b...side wall, 100...insulating cover, 100a...insulating cover, 100b...insulating cover, 100c, insulating cover, 110...plate material, 112...edge, 120...core material, 130...vacuum film, 132...hem, 140...support material

Claims

1. A heat-insulating lid for covering an opening of a heating tank having an open top surface, A plate member placed on a side wall of the heating tank; A core material is disposed under the plate material and fitted to the inside of the side wall of the heating tank; A vacuum film that contains the plate material and the core material, The core material is made of an open-cell foam, The vacuum film is larger in size than the plate material, The vacuum film is vacuumed to integrate the plate material and the core material in a stacked state, whereby a bottom edge of the vacuum film is formed on the outer periphery of the plate material, An insulating lid, characterized in that the bottom edge can be folded between the plate material and the side wall of the heating tank.

2. A rod-shaped support member is disposed on the upper side of the plate member and is enclosed in the vacuum film to function as a handle, 2. The insulating lid of claim 1, wherein the support member has a length spanning a pair of opposing side walls of the heating tank.

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