WO2014038023A1

WO2014038023A1 - Freezer

Info

Publication number: WO2014038023A1
Application number: PCT/JP2012/072655
Authority: WO
Inventors: 大木　武彦; 大木　達彦
Original assignee: 株式会社大木工藝
Priority date: 2012-09-05
Filing date: 2012-09-05
Publication date: 2014-03-13

Abstract

Provided is a freezer capable of reducing temperature differences due to location and rapidly lowering the temperature in the freezer. This freezer is suitable for refrigerated vehicles and is provided with a freezing machine for blowing cold air into the freezer. A composite sheet (4), which has a metal sheet (6), made of aluminum or the like, bonded to a graphite sheet (5), such as an expanded graphite sheet, is bonded to at least a side wall so that the temperature in the freezer is lowered by the cold air convection and the side walls, and the metal sheet (6) is exposed to the interior of the freezer.

Description

freezer

The present invention relates to a freezer suitable for a refrigerator car or the like.

Generally, a freezer attached to a freezer car has a heat insulating layer on the side wall, ceiling, floor, and rear door to prevent the cool air inside the refrigerator from escaping to the outside. In addition, a refrigerator (evaporator) is provided at a predetermined location on the side wall or ceiling to blow cool air into the warehouse to lower the temperature in the warehouse. In the freezer of this freezer, various proposals have been made regarding structures such as side walls. For example, Patent Document 1 discloses that a panel plate that forms a side wall of a freezer is disposed with two composite plates facing each other, and a core material (heat insulating layer) made of resin is adhered between the composite plates. It describes what has been sandwiched. The composite plate has a structure in which a heat insulating intermediate material made of polyethylene resin or the like is sandwiched between a front plate made of, for example, an aluminum plate and an inner plate. Since this panel board does not use wood, compared with it, heat insulation is improved and power consumption used to cool the inside of the cabinet can be reduced. In addition, lightness, rust resistance, and strength are reduced. But it is said to be good.

JP 2004-28434 A

By the way, in a freezer car, when loading cargo into the warehouse, it begins to blow out cold air from the refrigerator, so it is desirable to wait until the place where the cargo is placed falls below a certain temperature. If the waiting time is long, it consumes fuel and is inconvenient for efficient transportation system operation. However, it is normal that the temperature difference depending on the location is not small depending on the convection of the cold air, and the freezer of the conventional freezer including Patent Document 1 rapidly reduces the temperature difference depending on the location. Reducing the temperature is not considered much.

The present invention has been made in view of the above reasons, and an object of the present invention is to provide a freezer capable of rapidly lowering the temperature in the warehouse while reducing the temperature difference depending on the place.

In order to achieve the above object, a freezer according to a preferred embodiment of the present invention is provided with a refrigerator that blows out cool air into the refrigerator, and a composite sheet in which a metal sheet is bonded to a graphite sheet is attached to at least a side wall. The metal sheet is exposed in the cabinet.

Preferably, the graphite sheet is an expanded graphite sheet. Preferably, the metal sheet is made of aluminum. Preferably, the freezer is attached to a freezer.

According to the present invention, since the temperature in the cabinet is lowered from the side wall as well as the convection of the cold air, the temperature in the cabinet can be rapidly lowered while reducing the temperature difference depending on the place.

It is an external view when the rear door of the freezer of the freezer truck concerning the embodiment of the present invention is opened. It is a typical expanded sectional view which shows the side wall of the freezer same as the above, or the warehouse inner side of a ceiling. It is a graph which shows the experimental result of the freezer same as the above. It is a graph which shows another experimental result of the freezer same as the above.

Hereinafter, preferred modes for carrying out the present invention will be described. The freezer 1 which concerns on embodiment of this invention is a freezer attached to a freezer truck. As shown in FIG. 1, the freezer 1 has a side wall 21 (a front side wall 21a, a left side wall 21b, and a right side wall 21c), a ceiling 22, a floor 23, a rear door 24, a synthetic resin foam material, and the like. The heat insulation layer is prevented and the cool air in the cabinet is prevented from escaping to the outside. Moreover, this freezer 1 is provided with the refrigerator 3 which blows out cold air in the store | warehouse | chamber in the predetermined | prescribed location of the side wall 21 or the ceiling 22 like this, and the temperature in a store | warehouse | chamber is lowered | hung by this.

As shown in FIG. 2, the composite sheet 4 is attached to the inside of the side wall 21 and the ceiling 22. The composite sheet 4 is obtained by bonding a metal sheet 6 to a graphite sheet 5. The metal sheet 6 is exposed in the space inside the freezer 1.

The graphite sheet 5 is a graphite sheet in which an expanded graphite sheet (for example, a thickness of about 0.1 to 1 mm) is preferably used. The expanded graphite sheet is obtained by expanding a graphite such as natural graphite as a raw material into a form of expanded graphite, and then rolling (pressurizing to form a sheet). The graphite sheet 5 can make the ratio of the graphite component (carbon component) extremely high (for example, 99% or more) because the graphite particles are bonded to each other. Thereby, the graphite sheet 5 is very lightweight, is chemically stable, and has a high thermal conductivity and thermal diffusivity in the surface direction (direction orthogonal to the thickness direction). The thermal conductivity and thermal diffusivity can be changed depending on manufacturing conditions such as rolling.

The metal sheet 6 is a metal sheet suitably made of aluminum (for example, having a thickness of about 0.1 to 1 mm). Although the graphite sheet 5 is easy to break and graphite powder is easily generated, the metal sheet 6 improves the strength or durability against breakage of the graphite sheet 5 and the graphite powder from the graphite sheet 5 is reduced. It can be prevented from adhering to the luggage.

Table 1 shows specific examples of physical properties of the graphite sheet 5 of the expanded graphite sheet and the metal sheet 6 made of aluminum. In addition, the thermal conductivity and thermal diffusivity of the graphite sheet 5 shown here are those in the plane direction (direction orthogonal to the thickness direction).

Both the graphite sheet 5 and the aluminum metal sheet 6 have a low density and a high thermal conductivity and thermal diffusivity. When the graphite sheet 5 and the aluminum metal sheet 6 are compared according to Table 1, the density of the graphite sheet 5 is about half that of the aluminum metal sheet 6, that is, it is light. Further, the graphite sheet 5 can have a lower or higher thermal conductivity than the aluminum metal sheet 6. The graphite sheet 5 has a thermal diffusivity that is about 2 to 3 times higher than that of the aluminum metal sheet 6.

In such a freezer 1, the cold air blown out from the refrigerator 3 convects the inside of the refrigerator while being in contact with the side wall 21 or the ceiling 22. At the location where this convection is encountered, the heat it has absorbed is absorbed and the temperature drops, and the temperature of the air in the vicinity thereof gradually decreases. In the portion of the side wall 21 or the ceiling 22 that is in contact with the cold air blown out, the temperature of the air in the vicinity thereof gradually decreases, and the heat of the outer graphite sheet 5 is absorbed through the metal sheet 6. Then, the temperature of the peripheral side wall 21 or the ceiling 22 rapidly decreases due to thermal diffusion in the surface direction in the graphite sheet 5, and further, the temperature of the air in the vicinity thereof gradually decreases. Thus, since the temperature in the cabinet is lowered not only from the convection of the cold air but also from the side wall 21 or the ceiling 22, the temperature in the cabinet can be rapidly lowered while reducing the temperature difference depending on the place.

This freezer 1 can also be configured by diverting an existing freezer by attaching a composite sheet 4. In this case, the composite sheet 4 already formed by bonding the graphite sheet 5 and the metal sheet 6 may be attached to the side wall 21 or the ceiling 22. The composite sheet 4 can be easily cut according to the size of the side wall 21 and the ceiling 22, and can be easily bent and deformed along the unevenness of the side wall 21 and the ceiling 22. Moreover, since the composite sheet 4 can be made lightweight, they are easy to handle and work. Furthermore, the freezer 1 can be configured by modifying a normal container of a truck. In this case, the refrigerator 3 may be installed, a heat insulating layer may be provided inside the container, and the composite sheet 4 may be attached to the side wall 21 or the ceiling 22. As this heat insulating layer, a non-breathable one can be used as well as a breathable one or a substantially sealed air layer. In this case, the metal sheet 4 is formed between the inside and the heat insulating layer. It also serves to prevent air movement between them.

The experimental results showing the effect of the composite sheet 4 are as follows. In FIG. 3, the graphite sheet 5 of the expanded graphite sheet and the metal sheet 6 made of aluminum are bonded to the entire surface of the left side wall 21b, the right side wall 21c, the ceiling 22 and the rear door 24 where the fiber reinforced plastic is exposed on the inner wall surface. Comparing the freezer 1 (curve a) on which the formed composite sheet 4 was pasted with the freezer (curve b) in a state before the composite sheet 4 was pasted (in which the fiber reinforced plastic was exposed on the inner wall surface) as a comparative example. It shows a change in temperature after the refrigerator 3 is operated. As the composite sheet 4, a graphite sheet 5 having a thickness of about 1 mm and a metal sheet 6 having a thickness of about 0.15 mm was used. A refrigerator having a refrigerating capacity of 5.0 kW was used. The size of the freezer is about 1.8 m in width, about 1.8 m in height, and about 4.1 m in length. The outside air temperature is about 10 ° C. Curves a and b are both corners formed by the front side wall 21a and the floor 23 in the left side wall 21b and the corners formed by the front side wall 21a and the floor 23 in the right side wall 21c. This is the average of the temperatures in the vicinity of the part (B in FIG. 1). These places are the places where the cold air blown out from the refrigerator 3 reaches the farthest, so that the temperature is usually the lowest in the cabinet.

From FIG. 3, after 180 minutes, curve a reaches about −12 ° C., but curve b is about −7 ° C. From this, it can be seen that the temperature of the freezer 1 to which the composite sheet 4 is pasted is lowered more rapidly than the freezer in a state before the composite sheet 4 is pasted at a place where the temperature is difficult to decrease. Therefore, in the freezer 1, the temperature in the refrigerator can be rapidly lowered while reducing the temperature difference depending on the place.

The experimental results showing the effect of the graphite sheet 5 in the composite sheet 4 are as follows. FIG. 4 shows a freezer (curve c) in which a graphite sheet 5 of an expanded graphite sheet is attached to the entire surface of the left side wall 21b, the right side wall 21c, the ceiling 22, and the rear door 24 with aluminum exposed on the inner wall surface, and a comparative example. Is a comparison of the freezer (curve d) in a state before the graphite sheet 5 is pasted (a state in which aluminum is exposed on the inner wall surface), and shows a change in temperature after the refrigerator 3 is operated. It is. The graphite sheet 5 having a thickness of about 0.13 mm was used. A refrigerator having a refrigerating capacity of 5.1 kW was used. The size of the freezer is about 2.0 m in width, about 2.0 m in height, and about 4.8 m in length. The outside air temperature is about 35 ° C. Curves c and d are both the temperatures at the center of the interior.

From FIG. 4, it takes about 75 minutes for curve c to reach −10 ° C., whereas it takes about 83 minutes for curve d. From this, it can be seen that the graphite sheet 5 in the composite sheet 4 greatly contributes to lowering the temperature in the freezer 1.

As mentioned above, although the freezer which concerns on embodiment of this invention was demonstrated, this invention is not restricted to what was described in the above-mentioned embodiment, Various design changes within the range of the matter described in the claim are carried out. Is possible. For example, the composite sheet 4 can be affixed to all of the side wall 21, the ceiling 22, and the rear door 24. Conversely, depending on the case, the composite sheet 4 may be omitted from the ceiling 22 or the rear door 24, or the side wall 21. It is also possible to omit a part of.

In addition, the metal sheet 6 in the composite sheet 4 may be omitted in the side wall 21 or the ceiling 22 where it does not come into contact with luggage or people, and the graphite sheet 5 may be exposed in the cabinet. It is.

In addition, this freezer is suitable for a freezing vehicle because it can rapidly reduce the temperature inside the storage while reducing the temperature difference depending on the location, and the composite sheet 4 can be made very lightweight. It is applicable to other uses.

1 Freezer 21 Side Wall 22 Ceiling 3 Refrigerator 4 Composite Sheet 5 Graphite Sheet 6 Metal Sheet

Claims

There is a refrigerator that blows out cold air in the cabinet,
At least on the side wall, a composite sheet in which a metal sheet is attached to a graphite sheet is attached,
The freezer, wherein the metal sheet is exposed in the storage.
The freezer according to claim 1,
The freezer, wherein the graphite sheet is an expanded graphite sheet.
In the freezer according to claim 1 or 2,
The freezer, wherein the metal sheet is made of aluminum.
The freezer according to any one of claims 1 to 3,
The freezer is attached to a freezer car.