WO2008143537A1

WO2008143537A1 - Method and device for an irreversible indication of exceeding a set maximum temperature of frozen objects especially products

Info

Publication number: WO2008143537A1
Application number: PCT/PL2008/000036
Authority: WO
Inventors: Wojciech Chrzanowski; Waclaw Grzybkowski; Miroslaw Mecik; Czeslaw Poplawski; Malgorzata Kluczyk; Damian Zielinski; Pawel Wilkowski
Original assignee: Invenview Sp. Z O.O.
Priority date: 2007-05-17
Filing date: 2008-05-16
Publication date: 2008-11-27
Also published as: WO2008143537A4

Abstract

In the versions of the method implementation an indicating group comprising two subgroups is formed. In each of the subgroups immobilized water is placed. The subgroups are formed so that they may contact via water in the signalling condition. In some versions of the invention implementation there is a time scale fitted next to an indicating group. In one of the versions the device is characterized in that on the surface of the constructional element (1) favorably provided with a thermal insulation element (2) there is an indicating group (10e) that comprises two subgroups placed next to each other and containing substances that do not mix with each other and/or do not contact each other in the stand-by condition. The first subgroup (8e) is made of a gel and a permanent dye while the second subgroup (9e) consists of a gel.

Description

Method and device for an irreversible indication of exceeding a set maximum temperature of frozen objects especially products

The subject matter of the invention is the method and device for an irreversible indication of exceeding a set maximum temperature of frozen objects especially products.

The application No. WO 0172601 Al specifies an apparatus for an irreversible indication of a set maximum temperature of frozen products, which consists of an internal tank and an external tank filled with different solutions. In case of mixing, the solutions form a mixture of another colour. Upon freezing the formed ice breaks the internal tank and in case of defrosting the solutions pouring from tanks mix, which causes the tinge of the resulting mixture.

The Polish patent application No. P.370395 specifies an indicator of exceeding a defrosting temperature for frozen food products. This indicator comprises a foil bag with an indicating element inside made of a frozen liquid in the form of two-coloured lens. In case of defrosting the ice is melted and the colours of the liquids mix. It is not possible to return the indicator to the original form.

The application No. US6029601 specifies a thawing indication marker for frozen food for determining whether or not a frozen food has been thawed. It comprises a tube of an elastic transparent resin, the tube being bent at its center to form two separate containers. One container contains a coloured gel-like liquid prepared from an edible starch and food colour and the other container contains a gel-like liquid also prepared from an edible starch and food colour which is different from the first food colour. The marker is used by straightening the bent portion and applying it to frozen food. If the food undergoes thawing, as a result of being subjected to a temperature above the freezing point of water, the gels become less viscous and can intermingle. By virtue of the colour difference, one can observe whether or not any intermingling of the two different coloured gels has occurred and therefore, whether or not the food stuff has been subjected to non-thawing conditions.

The application No. WO2007116071 specifies an indicator of the keeping condition of products which makes it possible to detect whether the temperature of the product has exceeded a predetermined threshold, called the setpoint temperature. The indicator is comprising two transparent films assembled hermetically so as to enclose two canisters of liquid or viscous products. These canisters are being separated from one another by an adhesive joint hermetically connecting the opposing faces of the two films. The adhesive loses its adhesive properties when a predetermined temperature, referred to as the activation temperature of the indicator, is exceeded, in such a way that, if, after the activation of the indicator as a consequence of the exceedance of the activation temperature, the setpoint temperature is reached, then the viscous products are free to mix with one another.

The method for an irreversible indication of exceeding a set temperature of frozen objects especially products, which involves placing near a frozen product an indicating group containing water, that changes its colour after defrosting is characterized according to the present invention by placing on a waterproof constructional element or inside a waterproof constructional element, preferably with a rough surface, within a short distance two subgroups, which form an indicating group. The subgroups are formed so that in a signalling condition they can contact via water. The first subgroup is made of immobilized water, preferably containing substances that reduce its freezing point, and indicating substances, which are activated in the signalling condition in a water solution by activating substances. The second subgroup is made of immobilized water preferably containing substances reducing its freezing point and activating substances, which activate the indicating substances in the signalling condition in the water solution. If necessary an indicating group is sheltered with a preferably waterproof transparent protective element.

According to one embodiment of the invention a gel, which is made of water and a gelling agent, preferably agarose and/or gelatine is used as immobilized water.

According to the next embodiment of the invention the composition of each gel is selected so that a structure of first of them maintains its durability at a temperature lower than the structure of the second one, while a gel structure stabilising substance, preferably glycerol, is added to a gel with a structure which maintains its durability at a lower temperature.

According to another embodiment of the invention as an indicating substance a colour chemical indicator is used, preferably single-colour, and as a substance activating an indicating substance chemical buffer is used. According to yet another embodiment of the invention phenolphthalein is used as a colour chemical indicator, while a phosphate buffer is applied as a chemical buffer.

According to the other embodiment of the invention an indicating substance and an activating substance are selected so that they form a redox system.

According to the next embodiment of the invention the substance reducing the water freezing point is sodium chloride and/or calcium chloride and/or ethyl alcohol.

According to another embodiment of the invention the first subgroup and the second subgroup are aligned. In the signalling condition the length / of the colour zone is measured in the first subgroup and/or second subgroup, while the following formula:

where:

AT=T-T₀, where T₀ is a maximum set temperature of indication at which the activating and/or indicating substances solutions are melted in both subgroups,

7 - a temperature of an indicating group at any time in the indication condition, k - an indicating group constant, dependent on determined composition of the second gel by selecting its concentration and composition, is used to determine the time τ, when the indicating group, and at the same time the object, has remained at a temperature above the set maximum temperature.

The method for an irreversible indication of exceeding a set temperature of frozen objects especially products, which involves placing near a frozen product an indicating group containing water, that changes its colour after defrosting is characterized according to the present invention by placing on a waterproof constructional element or inside a waterproof constructional element, preferably with a rough surface, within a short distance two subgroups, which form an indicating group. The subgroups are formed so that in a signalling condition they can contact via water. The first subgroup is made of immobilized water, preferably containing substances that reduce its freezing point, and a permanent dye, which moves to the water solution in the signalling condition. The second subgroup is made of immobilized water. If necessary an indicating group is sheltered with a preferably waterproof transparent protective element. According to one embodiment of the invention a gel, which is made of water and a gelling agent, preferably agarose and/or gelatine is used as immobilized water.

According to another embodiment of the invention the substance reducing the water freezing point is sodium chloride and/or calcium chloride and/or ethyl alcohol.

According to yet another embodiment of the invention the first subgroup and the second subgroup are aligned. In the signalling condition the length / of the colour zone is measured in the second subgroup, while the following formula:

where:

AT-T-T₀, where T₀ is a maximum set temperature of indication at which the water solution is released from the first gel,

T - a temperature of an indicating group at any time in the indication condition, k - an indicating group constant, dependent on determined composition of the second gel by selecting its concentration and composition, is used to determine the time τ, when the indicating group, and at the same time the object, has remained at a temperature above the set maximum temperature.

The device for an irreversible indication of exceeding a set maximum temperature of frozen objects especially products, which consists of a constructional element and protective element and an indicating set containing water, that changes its colour after defrosting, is characterized according to the present invention by placing on a constructional element an indicating set containing three subsets placed near each other that contain substances that do not mix with each other and/or do not contact each other in the stand-by condition. The first subset is made of immobilized water, preferably containing a substance that reduces its freezing point. The second subset contains indicating substances that are activated in a water solution by an activating substance. The third subset contains activating substances that activate the indicating substances in the signalling condition in the water solution. The indicating set is sheltered with a protective element. The constructional element or the protective element preferably is provided with thermal insulation element.

According to one embodiment of the invention the second subset contains an indicating substance in a dry condition made of a colour chemical indicator, preferably single-colour. The third subset contains a dry substance that activates an indicating substance.

According to the next embodiment of the invention phenolphthalein is a colour chemical indicator. A substance that activates an indicating substance is a phosphate buffer. The substance reducing the water freezing point is sodium chloride and/or calcium chloride and/or ethyl alcohol.

According to another embodiment of the invention the immobilized water is made in the form of a gel, which is made of water and a gelling agent, preferably agarose and/or gelatine.

According to the other embodiment of the invention the first subset, the second subset and the third subset are spot-shaped.

According to yet another embodiment of the invention the third subset is spot- shaped and is surrounded with the first subset which is ring-shaped, which is surrounded with the second subset which is ring-shaped.

According to the next embodiment of the invention the second subset is spot- shaped and is surrounded with the first subset which is ring-shaped, which is surrounded with the third subset which is ring-shaped.

According to the other embodiment of the invention the first subset, the second subset and the third subset are stripe-shaped spots, while the first subset is located between the second subset and the third subset.

The device for an irreversible indication of exceeding a set maximum temperature of frozen objects especially products, which consists of a constructional element and protective element and an indicating group containing water, that changes its colour after defrosting, is characterized according to the present invention by placing on a constructional element an indicating set containing two subgroups placed near each other that contain substances that do not mix with each other and/or do not contact each other in the stand-by condition. The first subgroup is made of immobilized water, preferably containing a substance that reduces its freezing point, and indicating substances that are activated in a water solution by activating substances. The second subgroup contains activating substances that activate the indicating substances in the signalling condition in the water solution. The indicating group is sheltered with a protective element. Preferably the constructional element or the protective element is provided with thermal insulation element.

According to one embodiment of the invention the first subgroup contains an indicating substance in the form of a colour chemical indicator, preferably single- colour. The second subgroup contains a dry substance that activates an indicating substance.

According to yet another embodiment of the invention the first subgroup and the second subgroup are spot-shaped.

According to the other embodiment of the invention the first subgroup is spot- shaped and is surrounded with the second subgroup which is ring-shaped.

According to another embodiment of the invention the second subgroup is spot- shaped and is surrounded with the first subgroup which is ring-shaped.

According to yet another embodiment of the invention the first subgroup and the second subgroup are stripe-shaped spots.

The device for an irreversible indication of exceeding a set maximum temperature of frozen objects especially products which consists of a constructional element and protective element and an indicating group containing water, that changes its colour after defrosting, is characterized according to the present invention by placing on the surface of a constructional element an indicating group containing two subgroups placed near each other that contain substances that do not mix with each other and/or do not contact each other in the stand-by condition. The first subgroup is made of immobilized water, preferably containing a substance that reduces its freezing point, and activating substances that activate the indicating substances in the water solution in the signalling condition. In the second subgroup there are indicating substances that are activated by the activating substances in the water solution in the signalling condition. The indicating group is sheltered with a protective element. Preferably the constructional element or the protective element is provided with thermal insulation element. According to one embodiment of the invention the first subgroup contains an activating substance. The second subgroup contains a dry indicating substance in the form of a colour chemical indicator, preferably single-colour.

According to the next embodiment of the invention phenolphthalein is a colour chemical indicator, a substance that activates an indicating substance is a phosphate buffer. The substance reducing the water freezing point is sodium chloride and/or calcium chloride and/or ethyl alcohol.

According to the next embodiment of the invention the second subgroup is spot- shaped and is surrounded with the first subgroup which is ring-shaped.

According to another embodiment of the invention the first subgroup and the second subgroup are stripe-shaped spots.

The device for an irreversible indication of exceeding a set maximum temperature of frozen objects especially products, which consists of a constructional element and a protective element and an indicating group containing water, that changes its colour after defrosting, is characterized according to the present invention by placing on the surface of a constructional element an indicating group containing two subgroups placed near each other that contain substances that do not mix with each other and/or do not contact each other in the stand-by condition. The first subgroup is made of immobilized water, preferably containing a substance that reduces its freezing point, and indicating substances that in the signalling condition are activated by the activating substances in the water solution. The second subgroup is made of immobilized water, preferably containing a substance that reduces its freezing point, and activating substances that activate the indicating substances in the signalling condition in the water solution. The indicating group is sheltered with a protective element. Preferably the constructional element or the protective element is provided with thermal insulation element.

According to one embodiment of the invention the first subgroup and the second subgroup are placed in cavities that are connected preferably with a duct. According to another embodiment of the invention the cavities have the form of longitudinal and aligned grooves. Preferably on a constructional element graphic elements are fitted.

According to yet another embodiment of the invention the first subgroup and the second subgroup are aligned. Preferably graphic elements are fitted on a constructional element.

According to the next embodiment of the invention the immobilized water is made in the form of a gel, which is made of water and a gelling agent, preferably agarose and/or gelatine.

According to the other embodiment of the invention the indicating substance is a colour chemical indicator, preferably single-colour, and a substance activating an indicating substance is chemical buffer.

According to another embodiment of the invention phenolphthalein is a colour chemical indicator, a substance that activates an indicating substance is a phosphate buffer. The substance reducing the water freezing point is sodium chloride and/or calcium chloride and/or ethyl alcohol.

The device for an irreversible indication of exceeding a set maximum temperature of frozen objects especially products which consists of a constructional element and an indicating group containing water, that changes its colour after defrosting, is characterized according to the present invention by placing on a waterproof constructional element or inside a waterproof constructional element, preferably with a rough surface, indicating group containing two subgroups placed near each other that contain substances that do not mix with each other and/or do not contact each other in the stand-by condition. The first subgroup is made of the first gel, preferably containing a substance that reduces its freezing point, and a permanent dye that in the signalling condition moves to the water solution. The second subgroup is made of the second gel. If necessary an indicating group is sheltered with a protective element. The first gel contains less than 3% weight of a gelling agent. The second gel contains at least 3% weight of a gelling agent and a gel structure stabilising substance, preferably glycerol. Preferably the constructional element is provided with thermal insulation element.

According to one embodiment of the invention the first subgroup and the second subgroup are placed in separate cavities and are formed as longitudinal and aligned grooves separated with a threshold. Preferably graphic indicating elements are fitted on the constructional element. According to another embodiment of the invention the first subgroup and the second subgroup are aligned and preferably there are graphic indicating elements on the constructional element.

According to yet another embodiment of the invention the first subgroup and the second subgroup are placed in separate spatially formed compartments, preferably separated with a threshold. The compartments are inside the constructional element.

According to the other embodiment of the invention the compartments are aligned, preferably graphic indicating elements are fitted on the constructional element.

The device for an irreversible indication of exceeding a set maximum temperature of frozen objects especially products which consists of a constructional element and an indicating group containing water, that changes its colour after defrosting, is characterized according to the present invention by placing on a waterproof constructional element or inside a waterproof constructional element, preferably with a rough surface, an indicating group containing two subgroups placed near each other that contain substances that do not mix with each other and/or do not contact each other in the stand-by condition. The first subgroup is made of the first gel, preferably containing a substance that reduces its freezing point and indicating substances that in the signalling condition are activated by the activating substances in the water solution. The second subgroup is made of the second gel and activating substances that activate the indicating substances in the signalling condition in the water solution. If necessary an indicating group is sheltered with a protective element. The first gel contains less than 3% weight of a gelling agent. The second gel contains at least 3% weight of a gelling agent and a gel structure stabilising substance, preferably glycerol. Preferably the constructional element is provided with thermal insulation element.

According to one embodiment of the invention the first subgroup and the second subgroup are placed in separate cavities and are formed as longitudinal and aligned grooves separated with a threshold. Preferably graphic indicating elements are fitted on the constructional element.

According to another embodiment of the invention the first subgroup and the second subgroup are aligned and preferably there are graphic indicating elements on the constructional element. According to yet another embodiment of the invention the first subgroup and the second subgroup are placed in separate spatially formed compartments, preferably separated with a threshold. The compartments are inside the constructional element.

According to the next embodiment of the invention the compartments are aligned. Preferably graphic indicating elements are fitted on the constructional element.

In case of freezing the device, the physical structure of a gel in which the immobilized water is located is damaged by the forming ice. After that the system is in the stand-by condition, i.e. ready for indication.

In case of defrosting the device the ice melts and the released water forms a connection between subsets or subgroups. After that the system is in the signalling condition, which is apparent due to the irreversible change of colour of the indicating set or indicating group.

Another advantage of the invention compared to known devices is its preparation and storing that may be performed at positive temperatures.

A considerable advantage of the device is the automatic activation of the stand-by condition. The device features a simple structure and is easy to apply and store. The application of the thermal insulation element provides the control of the device indication dynamics and it is possible to control the delay of indications. The delay of indication may be also regulated with the distance between subgroups. Owing to the addition of substances that change a freezing point or a melting point of immobilized solutions, it is also possible to construct devices that indicate different set maximum temperatures, i.e. temperatures at which the solutions are gradually melted and released from both gels.

In some developed embodiments of the invention it is possible to measure the length of the extending colour zone, and by placing a time scale next to an indicating group, it is possible to read the approximate time when an indicating group, and at the same time an object, remains in conditions exceeding the set maximum temperature.

The invention has been explained in more detail in examples of its application and in the Figures, namely:

Fig. 1 presents the top view of a version of the device, Fig. 2 presents the section A-A of Fig. 1, Fig. 3 presents the top view of a version of the device, Fig. 4 presents the top view of a version of the device, Fig. 5 presents the section B-B of Fig. 4, Fig. 6 presents the top view of a version of the device, Fig. 7 presents the top view of a version of the device, Fig. 8 presents the top view of a version of the device, Fig. 9 presents the section C-C of Fig. 8, Fig. 10 presents the top view of a version of the device, Fig. 11 presents the section D-D of Fig. 10, Fig. 12 presents the top view of a version of the device, Fig. 13 presents the section E-E of Fig. 12,

Fig. 14 presents the top view of a version of the device before filling the constructional element by subgroups,

Fig. 15 presents the section F-F of Fig. 14 after filling the constructional element by subgroups,

Fig. 16 presents the top view of a version of the device after filling the constructional element by subgroups, in the signalling condition, Fig. 17 presents the top view of a version of the device before filling the constructional element by subgroups,

Fig. 18 presents the section G-G of Fig. 17 after filling the constructional element by subgroups,

Fig. 19 presents the top view of a version of the device after filling the constructional element by subgroups, in the signalling condition, Fig. 20 presents the top view of a version of the device before filling the constructional element by subgroups,

Fig. 21 presents the section H-H of Fig. 20 after filling the constructional element by subgroups,

Fig. 22 presents the top view of a version of the device after filling the constructional element by subgroups, in the signalling condition, Fig. 23 presents the top view of a version of the device before filling the constructional element by subgroups,

Fig. 24 presents the section I-I of Fig. 23 after filling the constructional element by subgroups,

Fig. 25 presents the top view of a version of the device after filling the constructional element by subgroups, in the signalling condition.

Example I

The device according to Fig. 1 and Fig. 2

A constructional element 1 sized 30 x 30 mm is made of a plastic sheet with a rough surface. A phosphate buffer of alkaline pH is spread in the shape of a circle with the diameter of 5 mm on the surface of the constructional element 1 with a brush. Around this third subset 6 and about 4 mm away a layer of 1% phenolphthalein in alcohol is formed with a drawing pen. The layer is ring-shaped, about 1 mm wide, and creates the second subset 5. The contact between the two subsets is prevented. After drying the second subset 5 and the third subset 6 a ring-shaped layer is formed between them with a drawing pen, made of 10% solution of sodium chloride and agarose in the condition shortly before solidification and the capacity of 15 mm³, thus creating the first subset 4. The first subset 4, the second subset 5 and the third subset 6 are sheltered with a protective element 3 in the form of a small dome made of transparent and waterproof plastic. On the constructional element 1 a foam tape (adhesive on one side) is stuck to create a thermal insulation element 2.

This device is fixed on packaging of a frozen object with a pressure-sensitive adhesive tape.

If a product is defrosted, the water solution released from the first subset 4 reaches the second subset 5 and the third subset 6. The created water solution with an alkaline reaction tinges the phenolphthalein raspberry red.

The resulting tinge is not changed after refreezing.

Example II

The device according to Fig. 3

The same procedure is followed as in the example I, however the first subset 4, the second subset 5 and the third subset 6 are made in the form of stripes, 20 mm long, and the first subset 4 is placed between the second subset 5 and the third subset 6. Example III

The device according to Fig. 4 and Fig. 5

A constructional element 1 sized 30 x 30 mm is made of a plastic sheet with a rough surface. A spot with the diameter of 5 mm is spread on the surface of the constructional element 1 with a brush. The spot is made of 10% water solution of sodium chloride, a phosphate buffer with an acid reaction and agarose in the condition shortly before solidification and the capacity of 18 mm³. After drying this first subgroup 8a about 2 mm away a ring-shaped layer is formed with a brush, about 1 mm wide, made of methyl orange, thus creating the second subgroup 9a.

The first subgroup 8a and the second subgroup 9a are sheltered with a protective element 3 in the form of a small dome made of transparent and waterproof plastic.

If a product is defrosted, the water solution released from the first subgroup 8a reaches the second subgroup 9a. The created water solution with an acid reaction tinges the methyl orange red (from yellow-orange).

Example IV

The device according to Fig. 6

A constructional element 1 sized 30 x 30 mm is made of a plastic sheet with a rough surface. A spot with the diameter of 5 mm is spread on the surface of the constructional element 1 with a brush. The spot is made of 10% water solution of sodium chloride, methyl orange and agarose in the condition shortly before solidification and the capacity of 18 mm³. After drying this first subgroup 8b about 2 mm away a ring-shaped layer is formed with a brush, about 1 mm wide, made of phosphate buffer of acid pH, thus creating the second subgroup 9b. The first subgroup 8b and the second subgroup 9b are sheltered with a protective element 3 in the form of a small dome made of transparent and waterproof plastic.

If a product is defrosted, the water solution released from the first subgroup 8b reaches the second subgroup 9b. The created water solution with an acid reaction tinges the methyl orange red (from yellow-orange).

Example V

The device according to Fig. 7 The same procedure is followed as in the example IV, however the first subgroup 8b and the second subgroup 9b are made in the form of stripes, 20 mm long, placed about 1 mm away from each other.

Example VI

The device according to Fig. 8 and Fig. 9

1. Determining the device constant k

A constructional element 1 sized 50 x 25 mm is made of a plastic sheet with a rough surface. A surface of the constructional element 1 is moulded so as to form two aligned cavities 16a and 16b in the form of grooves. The distance between the cavities 16a and 16b is 0.25 mm. A mixture of 10% sodium chloride solution, 1% phenolphthalein in alcohol and agarose in the condition shortly before solidification and the total capacity of 15 mm³ is spread in the cavity 16a with a drawing pen, thus forming the first subgroup 8c. A mixture of a phosphate buffer with alkaline pH and agarose in the condition shortly before solidification and the total capacity of 15 mm³ is spread in the cavity 16b with a drawing pen, thus forming the second subgroup 9c. The contact between the two subgroups is prevented. Along the first subgroup 8c and the second subgroup 9c on the surface of the constructional element 1 graphic elements 14a and 14b are drawn in the form of a scale. The first subgroup 8c, the second subgroup 9c and the graphic elements 14a and 14b are sheltered with a protective element 3 in the form of a small dome made of transparent and waterproof plastic.

The device prepared in that way is frozen and then defrosted in the constant temperature T and in the time τ.

In the course of defrosting a contact occurs between the first subgroup 8c and the second subgroup 9c through the released water. The formed water solution with an alkaline reaction tinges phenolphthalein raspberry red. In the first subgroup 8c there is the growth of the colour zone 11 while in the second subgroup 9c there is the growth of the colour zone 12.

After that the colour zone 11 and the colour zone 12 created in the time τ are measured. The device constant k is determined with the following formula:

where:

/ - the length of a colour zone AT=T-T₀, where T₀ is a maximum set temperature of indication at which the activating and/or indicating substances solutions are melted in both subgroups,

T - a device temperature at any time in the indication condition, T - a time when the device has remained at a temperature above the set maximum temperature.

Preferably the above operation is performed for several different values of T and then the records of the device constant k are averaged.

2. Making a device for indication of exceeding a set maximum temperature of frozen object

The device is made in the same manner as in Item 1. The device is fixed on packaging of a frozen product with a pressure-sensitive adhesive tape. After removing an product from a freezing system, which has become defrosted when in the system, the length / of the colour zone 11 is measured, while the following formula:

where:

AT=T-T₀, where T₀ is a maximum set temperature of indication at which the activating and indicating substances solutions are melted in both subgroups, T - a device temperature at any time in the indication condition, k - a device constant is used to determine the aproximate time τ, when the device, and at the same time a product, has remained at a temperature above the set maximum temperature. The resulting tinge is not changed after refreezing. The device shows exceeding the set maximum temperature of a frozen product and the time when the product has remained defrosted.

Example VII

The device according to Fig. 10 and Fig. 11

1. Determining the device constant k

A constructional element 1 sized 50 x 25 mm is made of a plastic sheet with a rough surface. A surface of the constructional element 1 is moulded so as to form two aligned cavities 15a and 15b in the form of grooves separated with a threshold 17a. The distance between the cavities 15a and 15b is 0.25 mm. A mixture of 10% sodium chloride solution, a gel with 1% content of agarose and a patent blue in the condition shortly before solidification and the total capacity of 15 mm³ is injected with a syringe into the cavity 15a, thus forming the first subgroup 8d. A gel with the content of 8% agarose in the condition shortly before solidification and the total capacity of 45 mm³ is injected with a syringe into the cavity 15b, thus forming the second subgroup 9d. The contact between the two subgroups is prevented. Along the first subgroup 8d and the second subgroup 9d on the surface of the constructional element 1 a graphic element 14c is drawn in the form of a scale. The first subgroup 8d and the second subgroup 9d and the graphic element 14c are sheltered with a protective element 3 made of transparent polyethylene ^' terephthalate (PET).

In the course of defrosting a contact occurs between the first subgroup 8d and the second subgroup 9d through the released water. The formed water solution causes the growth of the colour zone 18a in the second subgroup 9d. After that the colour zone 18a created in the time τ is measured. The device constant k is determined with the following formula:

where:

/ - the length of a colour zone 18a,

AT=T-T₀, where T₀ is a maximum set temperature of the indication at which the substances in the first subgroup 8d are melted,

T - a device temperature at any time in the indication condition,

T - a time when the device has remained at a temperature above the set maximum temperature.

2. Making a device for indication of exceeding the set maximum temperature of frozen object

The device is made in the same manner as in Item 1. The device is fixed on packaging of a frozen product with a pressure-sensitive adhesive tape. After removing a product from a freezing system, which has become defrosted when in the system, the length / of the colour zone 18a is measured, while the following formula:

where:

AT=T-T₀, where T₀ is a maximum set temperature of indication at which the substances in the first subgroup 8d are melted,

T - a device temperature at any time in the indication condition, k - a device constant, is used to determine the approximate time τ, when the device, and at the same time a product, has remained at a temperature above the set maximum temperature.

The resulting tinge is not changed after refreezing. The device shows exceeding a set maximum temperature of a frozen product and the time when the product has remained defrosted.

Example VIII

The device according to Fig. 12 and Fig. 13

1. Determining the device constant k

A constructional element 1 sized 50 x 25 mm is made of a plastic sheet with a rough surface. A surface of the constructional element 1 is moulded so as to form two aligned cavities 15c and 15d in the form of grooves separated with a threshold 17b. The distance between the cavities 15c and 15d is 0.25 mm. A mixture of 10% sodium chloride solution, a gel with the 1% content of agarose and 1% solution of phenolphthalein in alcohol in the condition shortly before solidification and the total capacity of 15 mm³ is injected with a syringe into the cavity 15a, thus forming the first subgroup 8e. A mixture of a gel with the content of 8% agarose and a phosphate buffer with alkaline pH in the condition shortly before solidification and the total capacity of 45 mm³ is injected with a syringe into the cavity 15d, thus forming the second subgroup 9e. The contact between the two subgroups is prevented. Along the first subgroup 8e and the second subgroup 9e on the surface of the constructional element 1 a graphic element 14d is drawn in the form of a scale. The first subgroup 8e, the second subgroup 9e and the graphic element 14d are sheltered with a protective element 3 made of transparent polyethylene terephthalate (PET).

The device prepared in that way is frozen and then defrosted in the constant temperature T and in the time τ. In the course of defrosting a contact occurs between the first subgroup 8e and the second subgroup 9e through the released water. The formed water solution increases the colour zone 18b by the length /. After that the length / of the colour zone 18b created in the time τ is measured. The device constant k is determined with the following formula:

where:

/ - a length of a colour zone 18b

AT=T-T₀, where T₀ is a maximum set temperature of indication at which the substances in the first subgroup 8e are melted,

T - a device temperature at any time in the indication condition, r - a time when the device has remained at a temperature above the set maximum temperature.

The device is made in the same manner as in Item 1. The device is fixed on packaging of a frozen product with a pressure-sensitive adhesive tape. After removing a product from a freezing system, which has become defrosted when in the system, the length / of the colour zone 18b is measured, while the following formula:

where:

T -a device temperature of at any time in the indication condition, k - a device constant, is used to determine the approximate time τ, when the device, and at the same time a product, has remained at a temperature above the set maximum temperature.

The resulting tinge is not changed after refreezing. The device shows exceeding a set maximum temperature of a frozen product and the time when the product has remained defrosted. Example IX

The device according Fig. 17 and Fig. 18 and Fig. 19 and Fig. 23 and Fig. 24 and Fig. 25

1. 1. Determining the device constant k

A water solution of patent blue is mixed with a gel with the 1% content of agarose forming the first mixture. By adding the ethyl alcohol the composition of the first mixture is determined for the set maximum temperature in which the substances are melted. After that the second mixture which contains 20% of glycerol and a gel with the 8% content of agarose is prepared. Inside the constructional element 1 in the form of pipe length 10cm and inner diameter 2mm made of transparent polyethylene (PE) and rough inner surface the second mixture in the condition shortly before solidification is sucked in 6cm length forming the second subgroup 9d. To the other pipe ending the first mixture in the condition shortly before solidification is injected with a syringe in 3,5cm length forming the first subgroup 8d. The contact between the two subgroups is prevented. Alongside of the second subgroup 9d on the constructional element 1 the graphic element 14e is drawn in the form of a scale. Both endings of the pipe are sealed permanently.

Further procedure is in a similar way to Example VII Item 1.

The device is made in the same manner as in Item 1. Further procedure is in a similar way to Example VII Item 2.

Example X

The device according Fig. 14 and Fig. 15 and Fig. 16 and Fig. 20 and Fig. 21 and

Fig. 22

1. 1. Determining the device constant k

A 1% solution of phenolphthalein in alcohol is mixed with a gel with the 1% content of agarose forming the first mixture. By adding the ethyl alcohol the composition of the first mixture is determined for the set maximum temperature in which the substances are melted. After that the second mixture which contains 20% of glycerol and a gel with the 8% content of agarose and a phosphate buffer of alkaline pH is prepared. Inside the constructional element 1 in the form of pipe length 10cm and inner diameter 2mm made of transparent polyethylene (PE) and rough inner surface the second mixture in the condition shortly before solidification is sucked in 6cm length forming the second subgroup 9e. To the other pipe ending the first mixture in the condition shortly before solidification is injected with a syringe in 3,5cm length forming the first subgroup 8e. The contact between the two subgroups is prevented. Alongside of the second subgroup 9e on the constructional element 1 the graphic element 14f is drawn in the form of a scale. Both endings of the pipe are sealed permanently.

Further procedure is in a similar way to Example VIII Item 1.

The device is made in the same manner as in Item 1. Further procedure is in a similar way to Example VIII Item 2.

Claims

1. The method for an irreversible indication of exceeding a set temperature of frozen objects especially products which involves placing near a frozen product an indicating group containing water, that changes its colour after defrosting characterized in that it involves placing on a waterproof constructional element or inside a waterproof constructional element, preferably with a rough surface, within a short distance two subgroups, which form an indicating group, and the subgroups are formed so that in a signalling condition they can contact via water, while the first subgroup is made of immobilized water, preferably containing substances that reduce its freezing point, and indicating substances, which are activated in the signalling condition in a water solution by activating substances, while the second subgroup is made of immobilized water preferably containing substances reducing its freezing point and activating substances, which activate the indicating substances in the signalling condition in the water solution, and if necessary an indicating group is sheltered with a preferably waterproof transparent protective element.

2. The method according to claim 1 characterized in that it uses as immobilized water a gel, which is made of water and a gelling agent, preferably agarose and/or gelatine.

3. The method according to claim 2 characterized in that the composition of each gel is selected so that a structure of one of them maintains its durability at a temperature lower than the structure of the second one, while a gel structure stabilising substance, preferably glycerol, is added to a gel with a structure which maintains its durability at a lower temperature.

4. The method according to claim 3 characterized in that as an indicating substance a colour chemical indicator is used, preferably single-colour, and as a substance activating an indicating substance chemical buffer is used.

5. The method according to claim 4 characterized in that phenolphthalein is used as a colour chemical indicator, while a phosphate buffer is applied as a chemical buffer.

6. The method according to claim 3 characterized in that an indicating substance and an activating substance are selected so that they form a redox system.

7. The method according to claim 1 characterized in that the substance reducing the water freezing point is sodium chloride and/or calcium chloride and/or ethyl alcohol.

8. The method according to claims 2 or 3 or 4 or 5 or 6 or 7 characterized in that the first subgroup (8c) and the second subgroup (9c) are aligned and in the signalling condition the length / of the colour zone (11, 12) is measured in the first subgroup (8c) and/or second subgroup (9c), while the following formula:

where:

9. The method for an irreversible indication of exceeding a set temperature of frozen objects, especially products which involves placing near a frozen product an indicating group containing water, that changes its colour after defrosting characterized in that it involves placing on a waterproof constructional element or inside a waterproof constructional element, preferably with a rough surface, within a short distance two subgroups, which form an indicating group, and the subgroups are formed so that in a signalling condition they can contact via water, while the first subgroup is made of immobilized water, preferably containing substances that reduce its freezing point, and a permanent dye, which moves to the water solution in the signalling condition, while the second subgroup is made of immobilized water, and if necessary an indicating group is sheltered with a preferably waterproof transparent protective element.

10. The method according to claim 9 characterized in that it uses as immobilized water a gel, which is made of water and a gelling agent, preferably agarose and/or gelatine.

11. The method according to claim 10 characterized in that the composition of each gel is selected so that a structure of one of them maintains its durability at a temperature lower than the structure of the second one, while a gel structure stabilising substance, preferably glycerol, is added to a gel with a structure which maintains its durability at a lower temperature.

12. The method according to claim 9 characterized in that the substance reducing the water freezing point is sodium chloride and/or calcium chloride and/or ethyl alcohol.

13. The method according to claims 9 or 10 or 11 or 12 characterized in that the first subgroup (8d) and the second subgroup (9d) are aligned and in the signalling condition the length / of the colour zone (18a) is measured in the second subgroup (9d), while the following formula:

where:

AT=T-T₀, where T₀ is a maximum set temperature of indication at which the water solution is released from the first gel,

14. The device for an irreversible indication of exceeding a set maximum temperature of frozen objects, especially products, which consists of a constructional element and protective element and an indicating set containing water, that changes its colour after defrosting, characterized in that it involves placing on a constructional element (1) an indicating set (7) containing three subsets placed near each other that contain substances that do not mix with each other and/or do not contact each other in the stand-by condition, while the first subset (4) is made of immobilized water, preferably containing a substance that reduces its freezing point and the second subset (5) that contains indicating substances that are activated in a water solution by an activating substance and the third subset (6) that contains activating substances that activate the indicating substances in the signalling condition in the water solution, therewith the indicating set (7) is sheltered with a protective element (3), while the constructional element (1) or the protective element (3) preferably is provided with thermal insulation element (2).

15. The device according to claim 14 characterized in that the second subset (5) contains an indicating substance in a dry condition made of a colour chemical indicator, preferably single-colour, while the third subset (6) contains a dry substance that activates an indicating substance.

16. The device according to claim 15 characterized in that phenolphthalein is a colour chemical indicator, a substance that activates an indicating substance is a phosphate buffer, while the substance reducing the water freezing point is sodium chloride and/or calcium chloride and/or ethyl alcohol.

17. The device according to claims 14 or 15 or 16 characterized in that the immobilized water is made in the form of a gel, which is made of water and a gelling agent, preferably agarose and/or gelatine.

18. The device according to claim 17 characterized in that first subset (4), the second subset (5) and the third subset (6) are spot-shaped.

19. The device according to claim 17 characterized in that the third subset (6) is spot-shaped and is surrounded with the first subset (4) which is ring-shaped, which is surrounded with the second subset (5) which is ring-shaped.

20. The device according to claim 17 characterized in that the second subset (5) is spot-shaped and is surrounded with the first subset (4) which is ring-shaped, which is surrounded with the third subset (6) which is ring-shaped.

21. The device according to claim 20 characterized in that the first subset (4), the second subset (5) and the third subset (6) are stripe-shaped spots, while the first subset (4) is located between the second subset (5) and the third subset (6).

22. The device for an irreversible indication of exceeding a set maximum temperature of frozen objects, especially products which consists of a constructional element and protective element and an indicating group containing water, that changes its colour after defrosting, characterized in that it involves placing on a constructional element (1) an indicating group (10a) containing two subgroups placed near each other that contain substances that do not mix with each other and/or do not contact each other in the stand-by condition while the first subgroup (8a) is made of immobilized water, preferably containing a substance that reduces its freezing point, and indicating substances that are activated in a water solution by activating substances while in the second subgroup (9a) there are activating substances that activate the indicating substances in the signalling condition in the water solution and the indicating group (10a) is sheltered with a protective element (3) while preferably the constructional element (1) or the protective element (3) is provided with thermal insulation element (2).

23. The device according to claim 22 characterized in that the first subgroup (8a) contains an indicating substance in the form of a colour chemical indicator, preferably single-colour, while the second subgroup (9a) contains a dry substance that activates an indicating substance.

24. The device according to claim 23 characterized in that phenolphthalein is a colour chemical indicator, a substance that activates an indicating substance is a phosphate buffer, while the substance reducing the water freezing point is sodium chloride and/or calcium chloride and/or ethyl alcohol.

25. The device according to claims 22 or 23 or 24 characterized in that the immobilized water is made in the form of a gel, which is made of water and a gelling agent, preferably agarose and/or gelatine.

26. The device according to claim 25 characterized in that the first subgroup (8a) and the second subgroup (9a) are spot-shaped.

27. The device according to claim 25 characterized in that the first subgroup (8a) is spot-shaped and is surrounded with the second subgroup (9a) which is ring- shaped.

28. The device according to claim 25 characterized in that the second subgroup (9a) is spot-shaped and is surrounded with the first subgroup (8a) which is ring- shaped.

29. The device according to claim 25 characterized in that the first subgroup (8a) and the second subgroup (9a) are stripe-shaped spots.

30. The device for an irreversible indication of exceeding a set maximum temperature of frozen objects especially products which consists of a constructional element and protective element and an indicating group containing water, that changes its colour after defrosting, characterized in that it involves placing on the surface of a constructional element (1) an indicating group (10b) containing two subgroups placed near each other that contain substances that do not mix with each other and/or do not contact each other in the stand-by condition while the first subgroup (8b) is made of immobilized water, preferably containing a substance that reduces its freezing point, and activating substances that activate the indicating substances in the water solution in the signalling condition and in the second subgroup (9b) there are indicating substances that are activated by the activating substances in the water solution in the signalling condition while the indicating group (10b) is sheltered with a protective element (3), and preferably the constructional element (1) or the protective element (3) is provided with thermal insulation element (2).

31. The device according to claim 30 characterized in that the first subgroup (8b) contains an activating substance, while the second subgroup (9b) contains a dry indicating substance in the form of a colour chemical indicator, preferably single-colour.

32. The device according to claim 31 characterized in that phenolphthalein is a colour chemical indicator, a substance that activates an indicating substance is a phosphate buffer, while the substance reducing the water freezing point is sodium chloride and/or calcium chloride and/or ethyl alcohol.

33. The device according to claims 30 or 31 or 32 characterized in that the immobilized water is made in the form of a gel, which is made of water and a gelling agent, preferably agarose and/or gelatine.

34. The device according to claim 33 characterized in that the first subgroup (8b) and the second subgroup (9b) are spot-shaped.

35. The device according to claim 33 characterized in that the first subgroup (8b) is spot-shaped and is surrounded with the second subgroup (9b) which is ring- shaped.

36. The device according to claim 33 characterized in that the second subgroup (9b) is spot-shaped and is surrounded with the first subgroup (8b) which is ring- shaped.

37. The device according to claim 33 characterized in that the first subgroup (8b) and the second subgroup (9b) are stripe-shaped spots.

38. The device for an irreversible indication of exceeding a set maximum temperature of frozen objects especially products which consists of a constructional element and a protective element and an indicating group containing water, that changes its colour after defrosting, characterized in that it involves placing on the surface of a constructional element (1) an indicating group (10c) containing two subgroups placed near each other that contain substances that do not mix with each other and/or do not contact each other in the stand-by condition while the first subgroup (8c) is made of immobilized water, preferably containing a substance that reduces its freezing point, and indicating substances that in the signalling condition are activated by the activating substances in the water solution and the second subgroup (9c) is made of immobilized water, preferably containing a substance that reduces its freezing point, and activating substances that activate the indicating substances in the signalling condition in the water solution while the indicating group (10c) is sheltered with a protective element (3), and preferably the constructional element (1) or the protective element (3) is provided with thermal insulation element (2).

39. The device according to claim 38 characterized in that the first subgroup (8c) and the second subgroup (9c) are placed in cavities (16a, 16b) that are connected preferably with a duct (13).

40. The device according to claim 39 characterized in that the cavities (16a, 16b) have the form of longitudinal and aligned grooves while preferably on a constructional element (1) graphic elements (14a, 14b) are fitted.

41. The device according to claim 38 characterized in that the first subgroup (8c) and the second subgroup (9c) are aligned and preferably graphic elements

(14a, 14b) are fitted on a constructional element (1).

42. The device according to claims 38 or 39 or 40 or 41 characterized in that the immobilized water is made in the form of a gel, which is made of water and a gelling agent, preferably agarose and/or gelatine.

43. The device according to claims 38 or 39 or 40 or 41 characterized in that the indicating substance is a colour chemical indicator, preferably single-colour, and a substance activating an indicating substance is chemical buffer.

44. The device according to claim 43 characterized in that phenolphthalein is a colour chemical indicator, a substance that activates an indicating substance is a phosphate buffer, while the substance reducing the water freezing point is sodium chloride and/or calcium chloride and/or ethyl alcohol.

45. The device for an irreversible indication of exceeding a set maximum temperature of frozen objects especially products which consists of a constructional element and an indicating group containing water, that changes its colour after defrosting, characterized in that it involves placing on a waterproof constructional element (1) or inside a waterproof constructional element (1), preferably with a rough surface, indicating group (1Od) containing two subgroups placed near each other that contain substances that do not mix with each other and/or do not contact each other in the stand-by condition while the first subgroup (8d) is made of the first gel, preferably containing a substance that reduces its freezing point, and a permanent dye that in the signalling condition moves to the water solution while the second subgroup (9d) is made of the second gel, and if necessary the indicating group (1Od) is sheltered with a protective element (3), and the first gel contains less than 3% weight of a gelling agent, while the second gel contains at least 3% weight of a gelling agent and a gel structure stabilising substance, preferably glycerol, and preferably the constructional element (1) is provided with thermal insulation element (2).

46. The device according to claim 45 characterized in that the first subgroup (8d) and the second subgroup (9d) are placed in separate cavities (15a, 15b) and are formed as longitudinal and aligned grooves separated with a threshold (17a), while preferably graphic indicating elements (14c) are fitted on the constructional element (1).

47. The device according to claim 45 characterized in that first subgroup (8d) and the second subgroup (9d) are aligned and preferably there are graphic indicating elements (14c) on the constructional element (1).

48. The device according to claim 45 characterized in that the first subgroup (8d) and the second subgroup (9d) are placed in separate spatially formed compartments (19a, 19b) preferably separated with a threshold (17c), while compartments are inside the constructional element (1).

49. The device according to claim 48 characterized in that the compartments (19a, 19b) are aligned to each other, while preferably graphic indicating elements (14e) are fitted on the constructional element (1).

50. The device according to claims 45 or 46 or 47 or 48 or 49 characterized in that, the substance reducing the water freezing point is sodium chloride and/or calcium chloride and/or ethyl alcohol.

51. The device for an irreversible indication of exceeding a set maximum temperature of frozen objects especially products which consists of a constructional element and an indicating group containing water, that changes its colour after defrosting, characterized in that it involves placing on a waterproof constructional element (1) or inside a waterproof constructional element (1), preferably with a rough surface, an indicating group (1Oe) containing two subgroups placed near each other that contain substances that do not mix with each other and/or do not contact each other in the stand-by condition while the first subgroup (8e) is made of the first gel, preferably containing a substance that reduces its freezing point and indicating substances that in the signalling condition are activated by the activating substances in the water solution and the second subgroup (9e) is made of the second gel and activating substances that activate the indicating substances in the signalling condition in the water solution and if necessary the indicating group (1Oe) is sheltered with a protective element (3), and the first gel contains less than 3% weight of a gelling agent, while the second gel contains at least 3% weight of a gelling agent and a gel structure stabilising substance, preferably glycerol, and preferably the constructional element (1) is provided with thermal insulation element (2).

52. The device according to claim 51 characterized in that the first subgroup (8e) and the second subgroup (9e) are placed in separate cavities (15c, 15d) and are formed as longitudinal and aligned grooves separated with a threshold (17b), while preferably graphic indicating elements (14d) are fitted on the constructional element (1).

53. The device according to claim 51 characterized in that first subgroup (8e) and the second subgroup (9e) are aligned and preferably there are graphic indicating elements (14d) on the constructional element (1).

54. The device according to claim 51 characterized in that the first subgroup (8e) and the second subgroup (9e) are placed in separate spatially formed compartments (19c, 19d) preferably separated with a threshold (17d), while compartments are inside the constructional element (1).

55. The device according to claim 54 characterized in that the compartments (19c, 19d) are aligned, while preferably graphic indicating elements (14f) are fitted on the constructional element (1).

56. The device according to claims 51 or 52 or 53 or 54 or 55 characterized in that the indicating substance is a colour chemical indicator, preferably single-colour, and a substance activating an indicating substance is chemical buffer.

57. The device according to claim 56 characterized in that phenolphthalein is a colour chemical indicator, a substance that activates an indicating substance is a phosphate buffer, while the substance reducing the water freezing point is sodium chloride and/or calcium chloride and/or ethyl alcohol.