SK77999A3 - Thermally insulated container - Google Patents

Description

Technical field

The invention relates to low temperature containers for maintaining the contents at temperatures below 10 ° C even when the ambient temperature is very high.

BACKGROUND OF THE INVENTION

Many perishable foodstuffs are transported / stored / distributed to consumers at temperatures below ambient temperature, either to prevent their biological deterioration (such as milk / fish / meat, etc.) or to protect their physical, olfactory and taste characteristics during consumption (soft drinks, frozen desserts, ice cream, etc.). Containers of different types and sizes are used for this purpose. In order to reduce the heat input to the stored products, they are thermally insulated. In addition, various heat sinks are used to maintain the cold content in these containers. For example, dry ice is sometimes added to the container to cause this effect. Alternatively, closed bags / liners containing a coolant can be used for this purpose as cooling batteries. Such coolants are precooled or pre-frozen at a sufficiently low temperature and packaged together with perishable foods to maintain them within the desired temperature range. These coolants can be stored freely. Alternatively, they may be aligned along the vertical walls using a retaining device to improve the accessibility of stored food products.

Coolants attached to the vertical walls of insulated containers used to store these food products are sometimes added with cooling solutions. The coolant can be permanently enclosed in a fixed housing. In such cases, the refrigerant may be cooled online, continuously or discontinuously, by the operation of small cooling units permanently attached to the vessel. Optionally, if the sheathed containers are to be movable, they can be taken periodically to a service station

- a station for pre-cooling / freezing the cooling solution in the jacket / liner by temporarily connecting it to the central refrigeration / freezer unit.

The refrigerant is removed into such freezers generally used in retail ice cream so that it can be fully or partially frozen using an installed freezer unit and provides the necessary cooling effect on the contents. Even if there are temporary power interruptions, or if the cabinet is disconnected from the power supply and removed for distribution by the vehicle, partially or fully frozen refrigerant continues to provide cooling effect until power is available to the unit.

However, the container designs described above have drawbacks. The stored goods cannot be kept within the desired temperature range for quite a long time, especially if the ambient temperature is very high only if the refrigerant / cooling surface is kept at temperatures well below the desired maximum temperature of the stored food products. For this, a pre-dimensioned freezing system must be used and this results in higher energy consumption. For example, in the case of ice cream, someone would like to distribute the product at and below -18 ° C for best results. A typical initial ice cream temperature at the time of filling is -20 ° C. It has been observed that under aggressive hot ambient conditions, as occurs in tropical countries, the temperature of ice cream stored in the containers described above increases rapidly above -18 ° C despite the presence of a cooling insert or jacket.

BR 9501576 discloses freezers adapted for storing frozen foods by using eutectic material inside a sheath or liner in a housing designed to maintain very low temperatures. Cooling temperatures of -27 ° C and below have been recommended to keep the ice cream at or below -18 ° C for a reasonable period of time. In general, this is an impractical or expensive option for tropical countries where ambient temperature is relatively high and even a small decrease in cooling temperature causes excessive demands on freezing systems, especially when the power source is irregular and expensive.

It is an object of the invention to provide a thermally insulated container which can maintain its contents at temperatures below 10 ° C under aggressive ambient conditions for a long time without

-3 using unusually low cooling surface temperatures.

It is a further object of the invention to provide a container particularly suitable for transporting / storing / distributing ice creams at and near -18 ° C for extended periods of time under aggressive ambient conditions without the aid of unusually low cooling surface temperatures.

A thermally insulated container has been found in which the temperature of the contents is kept below the setpoint for a long time without the aid of unusually low temperatures of cooling surfaces, by means of a continuous or segmented cooling surface with adequate coverage of the contents of the container. It has been found that optimum results can be obtained by providing a cooling surface that encapsulates the interior storage space of the container at about 70-100%.

SUMMARY OF THE INVENTION

The present invention provides a thermally insulated vessel for maintaining the temperature of articles stored in the inner cavity below 10 ° C, comprising an outer insulating jacket and a continuous or segmented cooling surface positioned between the outer insulating jacket and the inner cavity, causing more or total encapsulation of the inner cavity.

According to a preferred embodiment, the invention relates to a thermally insulated container for maintaining the temperature of objects stored in the inner cavity below 10 ° C, comprising an outer insulating jacket and a continuous or segmented cooling surface provided between the outer insulating jacket and the inner cavity causing 70-100% of the inner cavity .

According to a more preferred embodiment, the invention relates to a thermally insulated container for maintaining the temperature of articles stored in the inner cavity below 10 ° C, comprising an outer insulating jacket and a continuous or segmented cooling surface provided between the outer insulating jacket and the inner cavity causing 85 to 100% encapsulation of the inner cavity. .

According to a preferred embodiment, there is provided a container with an inner partition which defines the space between the outer casing and the inner partition. Container

The cross-member has a cooling surface for the space between the outer sheath and the inner partition or between the inner lining of the partition walls.

The temperature of the cooling surface is preferably in the range of 9 ° C to -45 ° C, and more particularly 9 ° C to -30 ° C.

The cooling surface may be provided in a variety of alternative forms, such as thermally conductive (e.g., metal) sheets attached to the coils or sealed shells / exchangers filled with the coolant, etc.

In a preferred embodiment of the invention, the coolant may be any suitable mixture so that the medium has a high heat absorption capacity of > 50 Joules / gram at and below the temperature range to which the content is to be protected. In a more preferred embodiment of the invention, the coolant has a heat absorption capacity of > 50 Joules / gram in the temperature range of -18 and -30 ° C. In another preferred embodiment of the invention, the coolant has a heat absorption capacity of> 120 Joules / gram between -18 and -30 ° C. Further, a refrigerant composition that is food compatible and has a very low corrosivity to commonly used inexpensive materials used in the construction of containers is preferred. The refrigerant may be selected from refrigerant gases such as R-12, LINE 30, aqueous solutions with added freezing temperature lowering or cryogenic or eutectic salt-water mixtures.

Advantageously, the cooling jacket completely encapsulates objects to be protected from heat exchange with the outside. The shape of the container may be a prism, a cube, a cylinder or any other suitable design. It is preferred that all the walls of the freezer are lined with a cooling jacket, so that they act as a thermal barrier between the stored objects and the outside atmosphere.

The cooling jackets and inserts may be made of a suitable material capable of withstanding low temperatures. Examples of suitable materials are low carbon steel, stainless steel, galvanized iron, plastics, polymers or other materials such as high, medium or low density polyethylene, linear low density polyethylene, polyvinyl chloride, polycarbonate, polyester, metal foil, etc. They can be packed in removable / removable units of different form, shape and size.

The invention and its advantages will be described in more detail by way of non-limiting examples of embodiments of the invention described below.

DETAILED DESCRIPTION OF THE INVENTION

Demonstration under conditions of sale

Six test data sets were generated for containers of different configurations used to sell ice cream. The vessel had 150 liters nominal capacity, 0.457 m height, 0.508 m width and 0.660 m length. The cap was 0.3 m x 0.5 m. The vessel was isolated with 75 mm PUF insulation (to about 25 mW / m.K). In all tests, the ambient temperature was 40 ° C. The relative humidity of the ambient air was 80%. The ice cream was filled at -20 ° C. The container cap was opened for 90 seconds every 10 minutes and the ice cream cone temperatures (Cornetto) in the container were recorded for 12 hours. Other parameters specific to each assay were as shown below.

Example 1

It was a container of conventional design with a cooling jacket on four vertical walls, enclosing 62% of the internal storage cavity and containing an aqueous solution of sodium acetate with sodium benzoate, which is the main additive as a cooling medium. The cooling surface was maintained at -20 ° C during the test.

Example 2

It was a container of conventional design with a cooling jacket on four vertical walls, enclosing 62% of the internal storage cavity and containing an aqueous solution of sodium acetate with sodium benzoate, which is the main additive as a cooling medium. The cooling surface area was increased by 50% by adding an additional cooling insert to the storage cavity of the container along with the ice cream.

-6 During the test, the cooling surface of the jacket and additional liner was maintained at -20 ° C.

Example 3

It was a conventional design vessel with a cooling jacket on four vertical walls enclosing 62% of the internal storage cavity and containing an aqueous solution of sodium acetate with sodium benzoate, which is the main additive as a cooling medium. The cooling surface area was increased by 100% by adding an additional cooling insert to the storage cavity of the container along with ice cream. During the test, the cooling surface of the jacket and additional liner was maintained at -20 ° C.

Example 4

It was a container of conventional design with a cooling jacket on four vertical walls, enclosing 62% of the internal storage cavity. The jacket contained a eutectic aqueous brine solution as a cooling medium. The cooling surface was maintained at -30 ° C during the test.

Example 5

It was a container of conventional design with a cooling jacket on four vertical walls, enclosing 62% of the internal storage cavity. The jacket contained a eutectic aqueous brine solution as a cooling medium. The cooling surface was maintained at -35 ° C during the test.

Example 6

It was a modified design vessel with a cooling jacket on the four vertical walls of the cabinet, enclosing 93% of the internal storage cavity containing an aqueous solution of sodium acetate with sodium benzoate, which is the main additive as a cooling medium. The cooling surface was maintained at -20 ° C during the test.

-7Table 1

Example Ice cream temperature after 12 hours exposure of the container at 40 ° C notes Example 1 The temperature of the ice cream rose very above -18 ° C unacceptable Example 2 Ice cream temperature increased above -18 ° C despite 50% increase in cooling surface unacceptable Example 3 Ice cream temperature increased above -18 ° C despite 100% increase in cooling surface unacceptable Example 4 The temperature of the ice cream rose above -18 ° C despite the use of a cooling surface maintained at a lower temperature of -30 ° C. unacceptable Example 5 Maintaining the cooling surface at a very low temperature of -35 ° C could keep the ice creams below -18 ° C for 12 hours The ice cream temperature is acceptable for 12 hours, but the cooling surface temperature is too low and not commercially practical Example 6 The ice cream temperature was kept below -18 ° C even if the cooling surface area was lower than that of Example 3 or the cooling temperature (-20 ° C) was much higher than in Example 5, all 6 sides being maintained as the cooling surface at just - 20 ° C. Maintains the desired product temperature efficiently and economically

Examples 1 to 6 show that improved design containers with a cooling jacket maintained at -20 ° C but completely or almost completely enveloping the contents of the container provided the best results in keeping the ice cream temperature below -18 ° C in a 12 hour sales cycle. Increasing the surface area of the cooling surface by up to 100% in a conventional treated container by adding an additional loosely refilled cooling insert not only increases the weight of the refrigerant, but has also been unable to keep the ice cream temperature below -18 ° C for a 12 hour sales cycle. Choosing a cooling jacket maintained at -35 ° C is not practical and would not be economical because the energy required to achieve lower and lower temperatures is significantly higher.

Demonstration under closing conditions

Six test data sets were generated for containers of different configurations used for ice cream storage. In the following Examples 7 to 12, the closure on the containers was kept closed during the test period and was not subjected to opening and closing. The vessel had 150 liters nominal capacity, 0.457 m height, 0.508 m width and 0.660 m length. The cap was 0.3 m x 0.5 m. The vessel was isolated with 75 mm PUF insulation (to about 25 mW / m.K). In all tests, the ambient temperature was 40 ° C. The relative humidity of the ambient air was 80%. The ice cream was filled at -20 ° C. Other parameters specific to each assay were as shown below.

Example 7

It was a conventional design vessel with a cooling jacket on four vertical walls, enclosing about 62% of the internal storage cavity. The jacket contained an aqueous brine solution as a cooling medium. The cooling surface was maintained at -26 ° C during the test. Cornetto ice cream temperatures in the container were recorded for 12 hours.

-9Example 8

It was a conventional design vessel with a cooling jacket on four vertical walls, enclosing about 62% of the internal storage cavity. The jacket contained an aqueous brine solution as a cooling medium. The cooling surface was maintained at -27 ° C during the test. Cornetto ice cream temperatures in the container were recorded for 12 hours.

Example 9

It was a conventional design vessel with a cooling jacket on four vertical walls enclosing about 62% of the internal storage cavity. The jacket contained an aqueous brine solution as a cooling medium. The cooling surface was maintained at -36 ° C during the test. Cornetto ice cream temperatures in the container were recorded for 50 days.

Example 10

It was a conventional design vessel with a cooling jacket on four vertical walls, enclosing about 62% of the internal storage cavity. The sheath contained an aqueous brine solution such as. The cooling surface was maintained at -37 ° C during the test. Cornetto ice cream temperatures in the container were recorded for 50 days.

Example 11

It was a vessel of modified design with a cooling jacket enclosing 93% of the internal storage cavity. The jacket contained an aqueous solution of sodium acetate and sodium benzoate as a cooling medium. The cooling surface was maintained at -20 ° C during the test. Cornetto ice cream temperatures in the container were recorded for 50 days.

-10Example 12

It was a vessel of modified design with a cooling jacket enclosing 100% of the internal storage cavity. The jacket contained an aqueous solution of sodium acetate and sodium benzoate as a cooling medium. The cooling surface was maintained at -20 ° C during the test. Cornetto ice cream temperatures in the container were recorded for 50 days.

Table 2

Example Ice cream temperature after test notes 7 above -18 ° C unacceptable 8 5 ° C The ice cream temperature is acceptable, but the cooling surface temperature is too low and not commercially practical 9 above -18 ° C unacceptable 10 5 ° C The ice cream temperature is acceptable, but the cooling surface temperature is too low and not commercially practical 11 5 ° C Effectively and economically maintains the desired product temperature even when the cooling surface temperature of -20 ° C was above the temperature for cases 7 to 10 12 5 ° C Effectively and economically maintains the desired product temperature even though the cooling surface temperature of -20 ° C was above the temperature for cases 7 to 10.

Examples 7 and 8 show that to maintain ice creams below -18 ° C for 12 hours, a cooling surface temperature of -27 ° C or less is required in a conventional design container with 62% storage cavity coverage, even when the closure is closed during 12 hours. hours.

Similarly, Examples 9 and 10 show that to maintain ice creams below -18 ° C for 50 days, a cooling surface temperature of -37 ° C or less is required in a conventional design container with 62% of the storage cavity pore when the closure is closed over time 50 days.

On the other hand, Examples 11 and 12 show that in a container of modified design providing 93% to 100% encapsulation of the cooling surface storage cavity, it is possible to keep ice cream below -18 ° C for 50 days, even when the cooling surface temperature is maintained at -20 ° C, which is far above the cooling surface temperature required in Examples 7 to 10.

This improvement in keeping the ice cream in the desired temperature range of -18 ° C, even if the cooling surface was maintained at a relatively high temperature of -20 ° C by ensuring that the cooling surface provides 70-100% of the ice cream storage cavity wrapping, is remarkable and unexpected.

Claims (6)

PATENT CLAIMS A thermally insulated container for maintaining the temperature of objects stored in its inner cavity below 10 ° C, characterized in that it comprises an outer insulating jacket and a continuous or segmented cooling surface, the cooling surface causing 70 to 100% encapsulation of the internal cavity. Container according to claim 1, characterized in that the cooling surface causes an encapsulation of 85 to 100%. Container according to claim 1 or 2, characterized in that the temperature of the cooling surface is from 9 to -30 ° C, preferably from -10 to -30 ° C. Container according to claims 1 to 3, characterized in that the cooling surface is formed by removable cooling inserts filled with a cooling medium. Container according to Claims 1 to 3, characterized in that the cooling surface is formed by thermally conductive plates connected to the cooling coils. Container according to one of Claims 1 to 3, characterized in that the container is free of electricity or other energy.