DD151358A5 - METHOD AND DEVICE FOR DETERMINING DEFROST SUPPLEMENTS - Google Patents

Abstract

Method and device for detecting and displaying defrosting processes, including temporary defrosting, of products which must be stored at temperatures below 0 ° C. The goal is to display defrosting operations safely and with little effort. The invention has for its object to indicate the total, repetitive temperature fluctuations or the total time that can be adjusted by inappropriate temperatures, taking into account a Verzoegerungszeit for permissible temperature changes. This is achieved according to the invention in that a water-soluble salt solution and a dyeing agent are separated by a mechanical release agent which is broken or removed by the change in the volume of the salt solution at the time of solidification and the salt solution and the dyeing agent can not mix as a result of their physical states that a further increase in temperature causes a visible and irreversible interaction between the solution and the dyeing agent.

Description

Berlin, 22,10,1980

^{Ap F 25 B} / ^{221 651} 57 628/23

Method and apparatus for detecting defrosting applicatio gsgebiet e r fin d un g

The invention relates to a method and a device for detecting and displaying defrosting processes, including temporary ones, of products which must be stored at temperatures below ⁰ ° C. *

Chara kteristik OeT _one known technically en Loes Ungen

Many products, for example in the chemical, pharmaceutical and food industry, must be stored at low temperatures. "A possible defrost. even if it happens accidentally and temporarily, it may harm these products or alter the characteristics of those products without the consumer being aware that the appearance may remain unchanged if the products are later frozen again. "

When considering the potential consequences of the use of products modified in their characteristics, the benefit of a method and / or devices which, or even if only temporary, are signaled by a display, is immediately recognized ", especially in the case of food "For example, in frozen foods, these devices must be extremely cheap, in addition to the safe and readily identifiable display, so that they can be used on products that are consumed to a great extent without affecting production costs." already devices which are suitable for display when a frozen product is exposed to temperatures,

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which are higher than the prescribed temperature are disadvantageous in that they are not so fast vvirken _{e to} determine even temperature fluctuations that occur only so briefly that they do not affect the product or that inaccurate displays are made, while on a continuous relationship between exposure temperature and permanence time at this temperature, without any real effective indication of the changes that occurred in the product _e

In frozen foods, an uninterrupted sequence of the so-called "cold chain" is essential to properly store the product without losses. "Insufficient normal temperature or occasional and periodic temperature fluctuations cause recrystallization phenomena of the water present in the product cells, causing subsequent development of ever larger crystals. so that they can break the cells themselves, causing the substrates and enzymes to come into contact with each other, thus causing such changes that have hitherto been prevented by the cold. "Since cold does not interrupt the enzyme activity but merely reduces it, a temperature increase even if it is only a partial increase, especially if it is periodic, creating conditions that may degrade the quality of the product *

On the other hand, the frozen product has a certain degree of thermal inertia due to the present supercooling and mass when housed in refrigerators, and is thereby protected against sudden environmental temperature fluctuations, so that this fact reduces the quality of the product.

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product is not affected, even if the product is stored for a short time (for example during transport) at an inappropriate temperature c

Object of the invention

The aim of the invention is to display defrosting operations, even temporary, of perishable products safely and with little effort,

Explanation of the essence of the invention

The invention has for its object to display the total, repetitive temperature fluctuations or the entire periods that set by unsuitable temperatures, taking into account a delay time for allowable temperature changes.

This is achieved according to the invention by separating an aqueous salt solution and a colorant with a mechanical release agent which is broken or removed by the change in the volume of saline solution at the time of solidification and the salt solution and the colorant can not mix due to their physical conditions in that a further increase in temperature causes a visible and irreversible interaction between the solution and the colorant. The temperature of the eutectic point of the saline solution is set as the calibration temperature. The coloring agent consisting of parts is provided with a receiving layer for producing a retarding effect.

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see"

The delay time is determined by the specific properties of the recording layer taking into account the properties of the salt solution and the layer thickness of the recording layer is determined depending on the dimensions of the parts

The receiving layer is produced by means of the microencapsulation process.

The device for carrying out the method is characterized in that an aqueous, the calibration temperature corresponding salt solution and a colorant are contained in the interior of a stable container, which are separated by means of a removable by increasing volume mechanical separator. The aqueous salt solution is selected for its eutectic temperature and the particulate colorant is covered with a receptor layer.

The parts provided with the receptive layer consist of granules coated by a process derived from that of microencapsulation. «

In a further embodiment of the device, a combination of several containers is made, each of which contains a salt solution with different eutectic point and display devices are provided with different colorants *

But it can be made a combination of a plurality of containers, which contain the same _f but aqueous salt solution different colorants that are treated so that they predetermined and different encryption

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create delays in the coloring of the liquid salt solution. The colorant is formed from a combination of two or more different colorants, each of which is treated to color the liquid salt solution with different delay times.

An essential feature of the invention is the exploitation of the physicochemical properties of an aqueous salt solution whose eutectic point provides the calibration temperature. In fact, the principle is used whereby an aqueous salt solution is completely in a solid state at a temperature lower than the eutectic point (z, B, ice plus solid salt).

Such a temperature, which is different for each of the selected solutions or solution mixtures, constitutes the calibration temperature of the device. Examination of the solidification diagram of an aqueous salt solution (Figure 8) reveals that the solution does not solidify to point B when an aqueous solution is present a salt weight percent, z, B, C, as the temperature is lowered

from the point t_ to the point t. , is used, a D

Once the point B is reached, z, B, when the outside temperature is lower than the point t. If some ice is separated from the solution, this leads to an increase in saline solution concentration. This happens until almost all the water is separated from the ice and the whole salt is crystallized when the temperature of the entire solution has once reached the ordinate t.

At point E the curve (eutectic point) the same conditions prevail water _f ice and solid salt together. Below point E, only ice and solid salt exist

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next to each other (solid eutectic),

The hatched part in Fig. 8 shows the area in which solution and ice are formed at the same time.

The dashed part shows the area where ice and solid eutectic coexist.

The part between release agent and the ordinate t shows the area in which solution and salt are present at the same time.

Table A lists some possible saline solutions with their corresponding eutectic points.

By utilizing the above properties of aqueous salt solutions, an aqueous saline solution having a known eutectic point (EP) can be treated with a colorant such that it does not dissolve in the liquid solution until a predetermined time elapses Saline and dom dyes before freezing prevent their mutual contact.

If the temperature falls below 0 C, the release agent is broken or removed by the increase in volume of the water, which separates from the salt present in the solution. Due to the solid state of the solution, the solution and the coloring agent do not mix when the solution reaches or exceeds the temperature according to the eutectic point. If the temperature is temporarily higher than the eutectic point, the solution dissolves and contacts the colorant, so that the solution stains by the colorant after a predetermined time and permanently retains the presumed coloration, even if it is subsequently re-frozen. With the occurring in the description

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By "release agent" is meant a mechanical agent that is disrupted, ruptured, punctured, or displaced from its location by volume enlargement of the aqueous salt solution.

Ausfüh rungsbeiepiel

The invention will be explained in more detail below using an exemplary embodiment. In the accompanying drawing show;

Fig. 1 shows the section through a device with a colorant arranged on the bottom, which is separated from the salt solution by a separating agent;

Fig. 2 shows the section through a device in which the colorant is stored in a fragile container;

3 shows the section through a further embodiment of the device;

4 shows the section through a further embodiment of the device with mechanical means for severing the dividing wall;

5 shows the section through a device combined from several containers;

6 shows the plan view of a further embodiment of the device;

Fig. 7: the section of the device according to Fig. 6;

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Fig. " 8: the freezing diagram of an aqueous salt solution »

Fig. 1 shows that in a stable holder 1 of non-deformable, non-toxic material, such as polystyrene, which is resistant to low temperatures, an aqueous salt solution 4 having a corresponding concentration is located.

The holder 1 is hermetically sealed by means of a cover 2 of transparent, stable material, eg, B, polystyrene of the crystalline type. "

The aqueous salt solution 4 is separated from a coloring agent 5 by means of a wall 3 made of a fragile material, eg »B _# glass film foil»

While the saline solution 4 completely fills the available space, the colorant 5 (z, B »correctly packaged dietary dye) is not, causing the aqueous saline solution 4 (which increases in volume during the freezing process) to the release agent for so long exerts pressure until it breaks * the colorant 5 is preferably treated with processes which are derived from the microencapsulation o 'ä », so that it is grained * Dedes grain is covered by a membrane whose chemical nature and thickness of the contact between Allow colorant 5 and the selected aqueous salt solution 4 after a predetermined time has elapsed. The reaction time is directly proportional to the membrane thickness and the size of the grains and inversely proportional to the temperature at which contact between the liquid aqueous salt solution 4 and the granular colorant 5 occurs; this time is referred to as "delay time" * Therefore, the salt solution 4 comes in during freezing

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breaking the release agent in contact with the colorant 5, but because it solidifies rapidly or because the protective membrane is present, it does not stain. After a reasonable predetermined time, the salt solution 4 dissolves the membrane covering the grains during defrosting and irreversibly takes on a color. This fact can be ascertained even in the case of a subsequent re-freezing, since the previously colorless saline solution has assumed a different color.

Fig. 2 shows a variation of the device according to the invention. It consists of a stable container 6 which is hermetically sealed by means of a transparent cover 7 and in which the aqueous salt solution 8 is contained. The properly treated colorant 10 is contained in a frangible capsule 9 which is broken by the saline solution 8 while it is freezing. In this case, the aforementioned frangible separating means consists of the friable capsule 9, Fig. 3 represents a further variation of the device. In this case the container consists of a capsule 11 of stable material, is filled with an aqueous salt solution 12 and has a recess 13, which is closed by a partition wall. During freezing, the saline solution 12 expands the dividing wall 14 by expansion and, during subsequent defrosting, allows contact with the coloring agent 15 contained in the recess 13. According to another embodiment (fig. 4), the frangible dividing wall 16 can be made of deformable, suitably stretched material and can be in contact with pointed or cutting elements 17, and it can divide the container 18 into two spaces. "

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When the aqueous saline solution contained in the upper space freezes, the increase in volume causes the partition wall 16 to rupture because of bumping against the sharpening or cutting elements 17. Thereafter, the saline solution during the freezing process, when it is in the liquid state, with the included in the lower space colorant come into contact "As apparent from the above facts it can be seen are the inventive devices according to a predetermined temperature (e.g., B, the limit temperature of the of a single product) and according to the type of aqueous salt solution used, the ternary eutectic point corresponding to the saline solution itself.

However, it is also possible to combine two or more devices, while each device has its own engineering design that is different from the other devices in terms of coloring agents and the different temperatures, "it can also two or more devices that contain the same salt solution , but treated with different colorants, combined so that it comes to color after different duration at temperatures that are higher than the calibration temperatures »

Has such a design of the device (Figure _# 5) an outer shell 19 which is divided into several independent parts, each part has its own coloring agent 20 which is separated by a breakable partition wall 21 of the saline solution 22, which could also be different can "Thus, this device is capable of different Abtaugrade or duration at high temperatures for different times to display" A simplified version of the above combination, the overall

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is suitable to indicate different residence times at a temperature which is higher than the calibration temperature, may consist of a stable shell which is similar to that described in Fig. 1 and has a frangible release agent which separates the aqueous salt solution from the colorant. The latter consists of a mixture of two or more different colorants, each of which has been treated to dye the liquid solution which it may come in contact with after a different time. The different colorants may also be packaged in one or more elements which consist of layers of folios, so that they can dissolve successively, but with increasing delays.

It is noteworthy that one of the main features of the invention is that the grains of the colorant are covered with a membrane, which delays the melting in an aqueous salt solution.

-This feature has a twofold advantage: First, it eliminates the shortcomings caused by the fact that, depending on the concentration between the freezing point and the eutectic point of a saline solution, a liquid solution remains which stains the indicating agent on contact with the coloring agent, and secondly Since, for any length of time (even if short), the device is at a temperature higher than expected, there is a drop in the delay time, it follows that the devices store the possible sudden temperature changes that reduce the delay deviation more and more, on which the device is calibrated until it comes to irreversible staining. This phenomenon occurs because the solution in a liquid state the grains

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attacks that contain the colorant, and this happens every time it comes in contact with the grains. When the solution is back in its solid state, there is no longer any contact between the solution and the colorant. After these more or less extensive effects, a point is reached where the colorant mixes and the indicator begins to change color.

This phenomenon occurs in a time when the delay time is over, which is very important because the temperature increases can be detrimental if they occur repeatedly, while brief single temperature increases will not affect and damage the product. So that the product can be exposed for a very short time to temperatures higher than the usual storage temperatures, the product itself not being significantly affected (eg, when a frozen food is temporarily taken out of the refrigerator, 80 that it is the product It is possible to introduce a "delay time" during which the liquid salt solution and the coloring agent do not begin to interact.

For a better understanding, another detailed example follows,

The device described here is particularly suitable for frozen food.

The apparatus shown in Fig. 6 and used for the experiment consists of a container 23 which has the shape of a square running parallel to the base plate (22 mm) and one. Height of 8.8 mm. The container 23 consists of a base plate 24, the

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by means of a cover 25 which can be inserted by pressure (Figure 7). The canton of the base plate 24 and the cover 25 are shaped so that they fit together. "On the bottom of the base plate 24 is a square recess 28 with a length of 5 mm and a depth of 2 mm. In the base plate 24, an upper step 31 having a length of 15.40 mm is further added.

The walls of the recess 28 are the same distance from the inner walls 27 of the cover 25, so that a timely diffusion of the colorant is promoted in the entire solution.

The cover 25 has a circular central piece 29 which protrudes on _e inwardly and has oblique sides fazettierte 30th

The thickness of the central piece 29 is set so that the gas bubble, which forms when the liquid solution enters the recess 28 of the display means, so equally

moderately as possible on the base of the cover 25, and the faceted sides prevent the device from becoming effective before use and after solution dissolution. The inner edges of the cover 25 are round, so that a better expansion of the gas bubble is possible. The fragile release agent (not shown in Fig. 7) consists of a square glass film foil having a length of 20 mm and a thickness of 0.130 to 0.145 mm. A quadric shape is therefore chosen for glass, because in the manufacture it is cheapest _e The frangible release agent is fixed to the lower edge 26 of the cover 25 by means of a silicone rubber layer of the type RTV Silastic 734

 Thus, a triple result is achieved:

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a) By pressure adjustment between the cover 25 and the base plate 24, it is possible to bring the release agent in the desired position in which a portion of the glue along the contact edges of the cover 25 and the base plate 24 can penetrate, whereby the strength of the device increases becomes"

b) Since the glue is applied on the upper part of the release agent, it does not reduce the expansion pressure of the solidifying solution and promotes the breaking of the glass »

c) After sizing, the release agent is clamped between the base plate 24 and the cover 25, whereby an even more effective breakage is achieved *

The step 31, which holds together with the lower edge 26 of the cover 25, the fragile release agent, is so long that the release agent bends by the pressure of the solidifying solution so that the breaking point is exceeded.

The device is made of certain materials. Opaque white polystyrene is used, for example, for the base plate 24 and crystalline (transparent) polystyrene for the cover 25. These materials have been selected because they are cheap and non-toxic at low temperatures. As the solution, a 19.7% aqueous ammonium chloride (NHCl) salt solution is used and as a colorant, the food dye E 124 (red), which is microencapsulated, so that a delay time of one hour is possible.

This coloring agent was chosen because it is a food (even if such a requirement is not indispensable because the substance is isolated in the indicating means)

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and it readily dissolved from the more than 50 colorants of the different variants studied in ammonium chloride, is not photosensitive and has a bright red color.

As a variation also yellow E 102 was examined, the results being similar to those of the previous example. Ammonium chloride solution was chosen because it is at the concentration used and amount of non-toxic, the eutectic point 15.8 ⁰ C, while frozen products are stored at most 18 ⁰ C in most countries.

When ammonium chloride is stored at this temperature, it is solid and snow white. The high concentration (19.7% corresponds to the eutectic concentration) became at a small interval in which, in the cooling phase, the liquid salt solution contacts the colored indicator , selected so that the freezing point is near the eutectic point.

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Table A

Some salt solutions and their corresponding eutectic points

Disodium maleate 0.4 ⁰ C

Sodium sulfate 1.1 ⁰ C

Monosodium citrate 2.1 ⁰ C

Potassium nitrate 2.9 ⁰ C

Magnesium sulfate 4.0 C

Trisodium citrate 6 * 9 ⁰ C

Potassium chloride 10.7 ⁰ C

Disodium citrate. 12.0 ⁰ C

Potassium bromide 13.0 ⁰ C

Ammonium chloride 15.4C

Dipotassium citrate 15.6 ^° C.

Sodium nitrate 18.5 ⁰ C

Sodium chloride 21.8 ⁰ C

Sodium bromide 28.0 ⁰ C magnesium chloride. 33.6 ⁰ C

Potassium carbonate 36.5 ⁰ C

Tripotassium 40.0 ⁰ C

Claims (11)

22/10/1980 AP F 25 B / 221 651 2-2 1611 ^ ^& - 17 -. 57 628/23 invention claim i "method for detecting and displaying defrosts, even from temporary defrosts, marked. characterized in that an aqueous salt solution and a colorant are separated by a mechanical release agent, which is broken or removed by the change in the volume of the salt solution at the solidification time and the salt solution and the colorant can not mix due to their physical states that a further increase in temperature causes a visible and irreversible interaction between the solution and the colorant » 2 _e method according to item 1, characterized in that the temperature of the eutectic point of the salt solution is set as the calibration temperature. 3 »method according to item 1, characterized in that the colorant consisting of parts is provided with a receiving layer for generating a retarding effect, 4 »Method according to item 3, characterized in that the delay time is determined by the specific properties of the recording layer taking into account the properties of the salt solution and the layer thickness of the recording layer is determined depending on the dimensions of the parts. 5 «Method according to item 4, characterized in that & the recording subject is produced by means of the microencapsulation method» 22 * 10.1980 η, «# * ft 4 AP F 25 Β / 221 - 18 - 57 628/23 6, apparatus for carrying out the method according to item 1 to 5, characterized in that inside a stable container (6) an aqueous saline solution (4) corresponding to the calibration temperature and a coloring agent (5) are contained, by means of volume increase removable mechanical separator are separated from each other, 7 _# Device according to item 6, characterized in that. the aqueous salt solution (4) is selected on the basis of its eutectic temperature and the coloring agent (5) consisting of parts is covered with a receiving layer » Device according to points 6 and 7, characterized in that the toils provided with the receiving layer consist of grains coated by a process derived from those of the microencapsulation, 9 9 1 6 S 1 AP F 25 B / 221 651 - 19 - 57 628/23 9, device according to points 6 to 8, characterized in that a combination of several containers is made, each of which contains a saline solution (22) with different eutectic point, and display devices with different coloring agents (20) are provided « 10, Device according to items 6 to 9, characterized in that a combination is made of several containers which contain the same aqueous salt solution, but different colorants that are treated so that they predetermined and liquid different delays in the dyeing dor in saline create"   22,10.1980 11, device according to the points 6 to 10, characterized in that the colorant of a combination
is formed by two or more different colorants, each of which is treated so as to color the liquid salt solution with different delay times »