JP2001201222A - Low-temperature cold insulating body and cryogenic refrigerating apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a low temperature cold reserving body with a modified structure and a simple cryogenic refrigerating apparatus, which enable keeping the temperature of a small quantity of article at about -25 deg.C or below for a prolonged time, while achieving safe handling thereof. SOLUTION: The low-temperature cold reserving body houses a refrigerating material, holding a composition having a specified melting temperature within a range of -25 deg.C to -60 deg.C in a heat transfer container, in a detachable semi- heat insulating vessel which is partially exposed or is not exposed. Moreover, the cryogenic refrigerating apparatus has the refrigerating material or the low temperature cold reserving body housed and fixed on a bottom part within a heat-insulating container. The composition used in the refrigerating material preferably contains calcium chloride or magnecium chloride, and water.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cold insulator and a cryogenic refrigeration apparatus, and more particularly, to a cold insulator capable of cooling a cold insulator to a very low temperature.

[0002]

2. Description of the Related Art Ice cream, seafood, and the like are commodities that need to be stored in a frozen state or transported in a frozen state. When handling large quantities of such products and the like, a freezer or a freezer equipped with a large-sized freezing device such as a mechanical type is used. Usually, dry ice is used to maintain a very low temperature, and there is no easy alternative to freezing.

[0003] However, since the volume of dry ice gradually decreases as it is gasified, it is difficult to keep the ambient temperature constant, and it is impossible to reuse it, and when released into the environment, it promotes global warming. There is a disadvantage of doing so. Also,
As a cold insulating material instead of such dry ice, a material in which a salt solution is filled in a container is known. But,
None of such cold insulators has the ability to maintain a temperature of -25 ° C or lower.

[0004]

SUMMARY OF THE INVENTION Therefore, the present invention solves the problems of the conventional cold insulator, and at the same time, can keep the temperature of the article at about -25.degree. C. or less for a long time and handle it safely. It is a first object to provide a low-temperature cold insulator having an improved structure that can be used. It is a second object of the present invention to provide a simple cryogenic refrigeration apparatus that has a structure for holding the low-temperature cold insulator of the present invention and that can keep an article at a low temperature for a long time. .

[0005]

An object of the present invention as described above is to provide a frozen material comprising a composition having a specific melting temperature in a range of -25 ° C to -60 ° C in a heat conductive container. Is partially exposed in a detachable semi-insulating container,
Alternatively, this can be achieved by a low-temperature cold insulator characterized by being housed without being exposed.

[0006] The heat conductive container in the cold insulator of the present invention is formed by using polyolefin, polyamide or polyurethane alone or by laminating, and at least a part of the wall is transparent or transparent. By forming the material so as to be translucent, the inside of the frozen material can be observed, and the effect of being safe and easy to use can be obtained.

[0007] The composition in the low-temperature cold insulator of the present invention preferably contains either calcium chloride or magnesium chloride and water, and further contains propylene glycol alginate for ease of handling and safety. From the viewpoint of properties, it is more preferable.

Further, another object of the present invention is achieved by a cryogenic refrigeration apparatus characterized in that the above-mentioned frozen material or the above-mentioned low-temperature chiller is housed and fixed at the bottom in a heat insulating container. it can.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In general, when a small amount of goods is to be transported by freezing, a heat insulating material previously cooled to a low temperature is stored in a heat insulating container such as a box made of expanded polystyrene together with the goods that need to be kept cool. Thus, the temperature of the internal space of the heat insulating container is kept low. It is well known that some of these cold insulators solidify or freeze upon cooling, absorb the heat of fusion when the solidified material melts, lower the temperature of adjacent articles, and maintain a low temperature state. is there. However, low-temperature cold insulators having a low melting temperature of -25 ° C. or less are considered to be difficult to put into practical use because the time for which low temperatures can be maintained is short, and all such cold insulators are about −20 ° C. It was only practical until now.

[0010] In order to prolong the cooling time of such a low-temperature cooling material, a method of enclosing a frozen composition having a low melting temperature in a container having a low thermal conductivity can be considered. But,
In this way, the surface temperature of the low-temperature insulating material does not decrease so much, and it takes several times longer than the use time to cool and solidify the insulating material for reuse. Was also grounds for not being put to practical use.

On the other hand, the low-temperature cold insulator according to the present invention is -2.
A semi-insulating material capable of mounting or demounting a frozen material obtained by enclosing a material selected from a composition having a melting temperature in a low temperature range of 5 ° C. to −60 ° C. in a heat conductive container. It is housed in a sex container. When using this, first, the frozen material is taken out of the semi-insulating container, put into a cryogenic refrigerator at an extremely low temperature to freeze-coagulate the composition, and then, the frozen frozen material is cut into a half according to the use conditions. It is housed in a heat insulating container and used as a low-temperature cold insulator. However, when the above-mentioned frozen material is used without being placed in a semi-insulating container, it is not suitable for the purpose of frozen storage or frozen transportation because the cooling time is short.

The composition having a low melting temperature used in the cold insulator of the present invention comprises either calcium chloride or magnesium chloride and water. The lowest temperature that can be reached with an aqueous solution of calcium chloride is-
51 ° C., the lowest temperature that can be reached with an aqueous solution of magnesium chloride is −33 ° C. In these aqueous solutions, a desired melting temperature of −25 ° C. or lower can be realized by changing the mixing ratio of salts and water. Therefore, it is possible to appropriately select and use a composition having a low melting temperature sufficient to maintain the frozen state of a food or the like and suitable for use conditions.
However, in the case of a frozen material prepared using a composition having a relatively high melting temperature, such as -15 ° C, the object to be cooled can be cooled only to about -10 ° C and cannot be used in the present invention. .

In the present invention, those which become a semi-gel composition after solidification by adding propylene glycol alginate to these aqueous solutions can be preferably used. When the container is damaged, such a composition does not need to be squirted out like an aqueous solution and can be deformed even when frozen, so that the container is hardly damaged and easy to handle. And the advantage of high security can be added.

Further, in the low-temperature cold insulator of the present invention, the composition having a low melting temperature is sealed in a heat-conductive container and used as a freezing material. It may be in the shape of a flat bottle or the like, and preferably has good thermal conductivity and does not easily cause perforation or breakage. Further, it is preferable that at least a part of the wall surface of the heat conductive container is transparent or translucent so that the frozen state of the contained composition can be observed. The composition used in the present invention becomes a white crystal when frozen, but when used in an incompletely frozen state, it has a property that the thawing rate is high and the cooling time is short, so such internal observation By using a container that can
It can be confirmed that the composition is completely frozen. Therefore, it is desirable that the heat conductive container according to the present invention is not subjected to a process such as coloring or printing that hinders the observation of the inside.

The good thermal conductivity of such a heat conductive container means that the heat dissipation from the surface of the container is good. For example, the heat transfer coefficient is preferably 0.01 W / m ² K or more. desirable. In order to manufacture such a container having good thermal conductivity, for example, a thermal conductivity of 0.25 to 0.3 W / m ·
If a resin material such as polyolefin, polyamide or polyurethane of K is used, transparency or translucency and toughness can be easily imparted to the heat conductive container.

Further, in the low-temperature cold insulator of the present invention,
The frozen material encapsulating the composition having a low melting temperature is used by being housed in a semi-insulating container that can be further attached and detached,
This semi-insulating container is intended to extend the low-temperature holding time by suppressing the flow of heat into the frozen material. Such a semi-insulating container is bottle-shaped,
The shape may be a bag, and the form is not particularly limited. However, it is preferable that the inner surface of the semi-insulating container has a shape that can be in close contact with the outer surface of the frozen material stored therein. .

Further, the entrance of the frozen material in the semi-insulated container may be opened and closed with a button, a string, a zipper, a magic tape, or the like after storing the frozen material,
Alternatively, sealing may be performed using an adhesive or an adhesive. Further, an opening may be provided other than the entrance of the frozen material, but the opening needs to be configured so that the frozen material does not deviate during use or the like. Also, if a part of the wall surface of the semi-insulating container can be opened, by exposing the heat-conductive container, the article requiring quenching can be brought into direct contact with the frozen material. There is an advantage that heat radiation from the surface is prevented and unnecessary cooling heat is not consumed.

The semi-insulating container as described above can be made of various semi-insulating materials alone or in combination. As a material used for producing such a semi-insulating container, a material having a thermal conductivity of about 0.15 W / m · K or less is preferable. And the thermal conductivity is 0.05W / m ·
For a material of about K, the thickness is about 1 mm and the thermal conductivity is 0.1
A material of about W / m · K has a thickness of about 2 mm, and a material having a thermal conductivity of about 0.15 W / m · K has a thickness of 3 to 4 mm.
When a semi-insulating container is made as a container having a thickness of about 5 to 6 mm with a material having a thermal conductivity of about 0.2 W / m · K and a thickness of about 5 to 6 mm, the cooling time is effectively extended. be able to.

Specific examples of such semi-insulating materials include foamed materials having a thermal conductivity of about 0.05 W / m · K, such as expanded polystyrene, expanded polyolefin, expanded polyurethane, expanded polyvinyl chloride, and the like. Cotton, feathers,
The thermal conductivity of wool, flannel, glass wool, etc. is 0.
The thermal conductivity of a fine fiber material of about 05 W / m · K, for example, Japanese paper, corrugated paper, non-woven fabric, knitted fabric, felt, etc. is 0.1 W
Fiber materials of about 1 W / m · K, for example, cork, chaff, asbestos, diatomaceous earth. Thermal conductivity of pumice etc. is 0.05-0.15
A porous material of about W / m · K;
Further, as a binding material for forming these materials into a desired shape, for example, various synthetic rubbers, various synthetic resins,
Examples include gypsum, cement, and other organic or inorganic binders. From the viewpoint of both handling and durability, these materials are desirably combined in a layered manner so as to have a small thickness and toughness to form a semi-insulating container.

As described above, the frozen material obtained by enclosing the liquid composition having a low melting temperature in a preferably flat heat conductive container is further accommodated in an appropriate semi-insulating container. And the low-temperature cold insulator of the present invention. In using such a low-temperature insulated body of the present invention, first, a frozen material contained in a semi-insulating container is taken out, frozen and solidified by a refrigerating device provided separately, and adapted to each use condition. The container is placed in a semi-insulated container having heat insulation properties, and placed in a heat-insulated container for cooling to hold the article to be cooled, together with the article to be cooled. At this time, the temperature of the frozen material itself is -2.
Since the temperature is as low as 5 ° C. or less, the article to be cooled can be sufficiently cooled, and long-term low-temperature cooling can be achieved. Then, in performing the regeneration of the low-temperature cold insulator after use, the frozen material stored in the semi-insulated container is taken out and only the frozen material is frozen and regenerated, so that the time of the regenerating operation is greatly reduced. be able to.

Further, in order to surely achieve long-term low-temperature cooling, it is effective to provide a cooling means at the bottom of the heat-insulating container for cooling. If the cooling means is provided at the top of the heat-insulating container for cooling, The present inventor has found that the cooling time is significantly reduced. The newly invented cryogenic refrigeration apparatus has the above-mentioned frozen material or low-temperature cold insulator housed and fixed at the bottom in a heat insulating container for keeping cold.

As such a heat insulating container, for example, a box-shaped container made of expanded polystyrene is preferably used, but it is not necessarily limited to this. The fixing means of the frozen material or the low-temperature cold insulator provided at the bottom of the container is, for example, rotatably attaching a holding plate or a holding net via a hinge to a substrate or a base frame fixed to the bottom of the container. , Frozen material or cold insulation,
What is sandwiched between a substrate or a base frame and a holding plate or a holding net and fixed by an appropriate locking tool or an elastic spring can be used. Alternatively, a foamed polyethylene plate or the like provided with a handle at the upper portion may be fitted so as to be in contact with the inner wall of the box-shaped container, and the lower portion of the container may be prevented from easily moving. However, the fixing means is not limited to these, and may have an appropriate structure.

In the cryogenic refrigeration apparatus of the present invention, the frozen material or the low-temperature cooler is fixed by the fixing means provided at the bottom in the heat-insulating container for cooling, and the article to be cooled is stored in the heat-insulating container. Because it is sealed, even if shaking or vibration is applied during transportation, the frozen material or the low-temperature cold insulator does not move in the heat insulating container, and therefore, the cool air in the heat insulating container is stirred. There is no. Therefore, the frozen material or the low-temperature cold insulator is maintained in a state surrounded by the coldest air at the lowest temperature, and cold can be kept for a long time without wasting cold heat.

[0024]

EXAMPLES The present invention will be described below in detail with reference to examples, but the present invention is not limited by the description of the examples.

(Example 1) 30% by weight of calcium chloride
500 g of a composition (A) composed of an aqueous solution was
Length 20cm, height 2.5cm, wall thickness 1.5mm
Then, the container was filled in a rectangular low-density polyethylene container (a) having a heat transfer coefficient of 0.015 W / m ² K, and was frozen using dry ice to obtain a frozen material (G). And the thickness 1m
m and a heat transfer coefficient of 0.001 W / m ² K, wrapped in an expanded polystyrene-aluminum laminate sheet (e),
A low-temperature cold insulator (Q) of the present invention was obtained.

The 3 mol% aqueous solution of ammonium chloride has a melting point of -15.5 ° C., but has a heat of fusion of 79.8 cal / g, which is the largest value for a refrigerating agent composed of an aqueous salt solution. It is practically used as a refrigerating agent for keeping 15 ° C. for a long time. Therefore, for comparison, a composition (B) 5 comprising a 3 mol% ammonium chloride aqueous solution was used.
In the same manner as described above, the container (a) was filled with 00 g, and frozen at −25 ° C. using dry ice to obtain a frozen material (H) of a comparative example. The composition (A) was substantially the same in outer shape as the container (a), but had a wall thickness of 0.05.
mm, the container (b) having a heat transfer coefficient of 0.5 W / m ² K was filled and frozen in the same manner as above to obtain a frozen material (I) of a comparative example.

The low-temperature cold insulator (Q), the frozen material (H), and the frozen material (I) are placed on a foamed polystyrene plate having a thickness of 2 cm, and placed in a room at 25 ° C. with an open top surface. It was investigated how the temperature measured by a thermometer sandwiched between the frozen material and the expanded polystyrene plate changes with time. The results are shown in Table 1. From these results, the low-temperature cold insulator (Q) of the present invention using the thick polyethylene container (a) and wrapping it with the sheet (e) is -2.
While maintaining a low temperature of 5 ° C. or less, the frozen material using a thin polyethylene container (b) has the same retention time as the frozen material (H) using an aqueous ammonium chloride solution having a large heat of fusion ( I) shows that the retention time is significantly shorter.

[0028]

[Table 1]

(Example 2) Container (a) used in Example 1
Was filled with 500 g of a composition (C) composed of a 26% by weight aqueous solution of calcium chloride, and frozen using dry ice to obtain a frozen material (J). And a foamed polyethylene having a thickness of 1 mm and a heat transfer coefficient of 0.0015 W / m ² K,
It was wrapped with a polyester laminate sheet (f) to obtain a low-temperature cold insulator (R) of the present invention. Then, 500 g of the mass of dry ice and the frozen material (J) were placed on a foamed polystyrene plate having a thickness of 2 cm in the same manner as in Example 1, and the holding time between the frozen material (J) and the dry ice was compared. did.

As a result, dry ice was reduced to 1 /
In 4 and 4 hours, the volume was reduced to 1/5 and the ability to freeze the articles was remarkably reduced. On the other hand, the cold refrigerating body (R) of the present invention had a temperature of -45 ° C after 1 hour. -4 hours later
0 ° C, -28 ° C after 3 hours, -15 ° C after 3 hours and a half
It became -4 degreeC after time, and it turned out that it shows the freezing performance comparable to dry ice.

Example 3 30% by weight of calcium chloride
500 g of a composition (A) composed of an aqueous solution was added to a thickness of 0.05
mm, a nylon-laminated polyethylene sheet bag (c) having a heat transfer coefficient of 0.3 W / m ² K, filled with crushed dry ice, frozen for 3 hours, and frozen. ) Got. The frozen material (K) was covered with a bag-like container (g) formed of a laminated sheet of an aluminum-evaporated polyester film and a 1-mm-thick foamed polyethylene sheet to obtain a low-temperature cold insulator (S) of the present invention.

Propylene glycol alginate (reagent: 150 cp or more) was added at a ratio of 8 g to 500 g of the above composition (A) to obtain a viscous liquid composition (D). Except that this composition (D) was used in place of the composition (A), a frozen material (L) was prepared in exactly the same manner as the frozen material (K) described above, and further covered with a bag (g). Thus, a low-temperature cold insulator (T) of the present invention was obtained.

With respect to the low-temperature cold insulators (S) and (T) of the present invention thus produced, a change in the temperature of the lower surface of each low-temperature cold insulator was examined in the same manner as in Example 1.
The results are shown in Table 2. From Table 2, it can be seen that the low-temperature cooler (S) of the present invention and the low-temperature cooler (T) of the present invention have almost the same cold-holding characteristics.

[0034]

[Table 2]

Example 4 The viscous liquid composition (E) was obtained by adding 5 g of the propylene glycol alginate used in Example 3 to 500 g of a 22% by weight aqueous solution of magnesium chloride. Then, instead of the composition (A), the composition (E) was added to the container (c) used in Example 3.
Fill and contact with crushed dry ice and freeze,
A frozen material (M) having a melting temperature of -33 ° C was obtained. Also,
A control frozen material (N) was obtained in the same manner as described above except that 500 g of the composition (B) composed of the aqueous ammonium chloride solution used in Example 1 was used instead of the composition (E).

A bag (h) made of expanded polystyrene having a thickness of 2 mm and laminated with a polyethylene film was tightly covered on the frozen material (M) to obtain a low-temperature cold insulator (U) of the present invention. And this low-temperature cold insulator (U) 2
Each piece is inner length 26cm, width 20cm, depth 20cm
And placed in a foamed polystyrene insulating container (k) having a thickness of 2 cm. Two pieces of the control frozen material (N) were also placed in the same heat-insulating container (k) as above, and each heat-insulating container was left in a room at 25 ° C. and sandwiched between low-temperature cold insulators. The temperature was measured over time with a thermometer, and the cooling time was examined. The results are shown in Table 3. As shown in Table 3, the low-temperature cold insulator (U) of the present invention using the composition (E) containing magnesium chloride was a control frozen material (U) using the composition (B) containing ammonium chloride. It can be seen that N) is significantly better than when used as is.

[0037]

[Table 3]

Example 5 The container (c) used in Example 3 was replaced by the composition (F) comprising a 22% by weight aqueous solution of magnesium chloride instead of the composition (E) used in Example 4.
Was frozen at −50 ° C. in exactly the same manner as in Example 4 to obtain a frozen material (O). Further, the frozen material (O) was put into a bag (i) formed of expanded polystyrene having a thickness of 2 mm and laminated with aluminum, and was placed at -31 ° C.
, A low-temperature cold insulator (V) of the present invention capable of maintaining the above temperature was obtained.

(Example 6) Container (a) used in Example 1
When the product (F) used in Example 5 was filled with the product name and the handling method printed on one surface and frozen, it was observed that a white frozen product was formed. Was. When the freezing was incomplete, it was possible to easily identify that the liquid remained.

(Embodiment 7) The bag (g) used in Embodiment 3 has a width of 10 cm and a length of 16
A low-temperature cold insulator (W) of the present invention in which a frozen material (O) prepared in Example 5 was housed and a heat conduction portion was exposed by providing a cutout of cm. When the article to be cooled was brought into direct contact with the exposed portion of the low-temperature cold insulator (W) and observed,
It has been found that the article to be cooled is cooled rapidly.

Example 8 The composition (E) used in Example 4 was filled in the same container (b) as used in Example 1, placed in a freezer at -70 ° C. and frozen. A frozen material (P) was obtained. Then, this frozen material (P) is
The low-temperature cold insulator (X) of the present invention was placed in a bag (j) formed of a foamed polyethylene sheet having a thickness of 2 mm so as to be in close contact with the bag. Two of the low-temperature cold insulators (X) were placed in an insulating box (k) made of expanded polystyrene having a width of 25 cm, a length of 20 cm, and a depth of 20 cm and having a thickness of 2 cm and fitted to the bottom. The cryogenic refrigeration system (Y) of the present invention was formed by fixing with a holding plate. And put on the rocking test machine,
The heat insulation box was shaken up and down twice with the hand in hand every 0 minutes, and how the temperature in the apparatus changes with time was examined.

The heat-insulating box (l) has the same structure as the heat-insulating box (k), but differs only in that no holding plate is fitted.
A cryogenic refrigeration system (Z) for control was formed in exactly the same manner as described above, and the manner in which the temperature in the system changed with time was examined in the same manner as described above. The results are also shown in Table 4. As compared with the control cryogenic refrigeration apparatus (X), the cryogenic refrigeration apparatus (W) of the present invention is a very efficient refrigeration apparatus and has a sufficient holding time. It turns out that it is long.

[0043]

[Table 4]

[0044]

Industrial Applicability The low-temperature cold insulator of the present invention is capable of attaching and detaching a frozen material comprising a composition having a specific melting temperature in the range of -25 ° C to -60 ° C in a thermally conductive container. The cryogenic refrigeration apparatus of the present invention is also characterized in that the cryogenic material or the cryogenic cooler is housed at the bottom in the heat insulating container. And fixed, so that even small quantities of frozen foods and other products that require long-term storage, especially at low temperatures, can be efficiently stored frozen or transported frozen, making it easy to recycle and economical In addition, it has the effect of contributing to the prevention of global warming.

Claims (6)

[Claims] 1. A frozen material comprising a composition having a specific melting temperature in a range of -25 ° C. to -60 ° C. in a thermally conductive container is partially contained in a detachable semi-insulating container. A cold insulation body characterized by being exposed or housed without being exposed. 2. The method according to claim 1, wherein the heat conductive container is a polyolefin,
The low-temperature cold insulator according to claim 1, which is formed using a polyamide or a polyurethane. 3. The low-temperature cold insulator according to claim 1, wherein at least a part of the wall surface of the heat conductive container is formed to be transparent or translucent. 4. The low-temperature cold insulator according to claim 1, wherein the composition comprises either calcium chloride or magnesium chloride and water. 5. The low-temperature cold insulator according to claim 1, wherein said composition further comprises propylene glycol alginate. 6. A cryogenic refrigeration apparatus, wherein the refrigeration material or the cryogenic body is housed and fixed at the bottom in a heat insulating container.