JPH01116421A - Method and apparatus for monitoring temperature for refrigerated and frozen goods - Google Patents

Abstract

PURPOSE: To monitor the temperature of a frozen product by shifting a container that contains an indicating liquid that is frozen or melted at a specific temperature in one or a plurality of cavities to an initial posture and freezing the indicating liquid at a first volume part of the cavity owing to the influence of gravity. CONSTITUTION: While an indicating liquid 3 is located at the lower part of a cavity due to the influence of gravity, a tracer is inserted into a cooling device, thus freezing the indicating liquid 3. After the freezing, by rotating the tracer, the tracer maintains the state as long as temperature does not exceed the melting temperature of the indicating liquid 3. However, when the critical melting temperature is exceeded, the liquid body 3 returns to its original state again. Therefore, the excess of the critical temperature can be clearly identified even after operation interruption is completed.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method and apparatus for monitoring the temperature of refrigerated or frozen goods.

PRIOR ART AND ITS PROBLEMS Frozen foods can be stored satisfactorily only if they are kept continuously below a critical temperature without interruption. This critical temperature is determined to be, for example, about -18° C. or lower for frozen products. Thawing and refreezing for a short period of time can transform the food into something harmful enough to pose a health risk.

For certain foods, the critical temperature is between -12°C and below -8°C. This is because it has been shown that bacteria thrive at these temperatures.

Even if the freezer and freezer cabinet are perfect, it is impossible to exclude the effects of contingencies. For example, this includes relatively long power outages, failures of refrigeration compressors, etc. Human causes can also lead the temperature to reach unreasonable values. This includes, for example, doors not closing properly or children handling refrigerated items.

Temperature monitoring with thermometers is not sufficient. I mean,
This is because, after a relatively long power outage, the refrigeration equipment starts working properly again, and thawing cannot necessarily be indicated when melted food is refrozen.

SUMMARY OF THE INVENTION An object of the present invention is to provide a device and method suitable for displaying the excess of a critical temperature using a type of thermometer and also taking into account the time during which the temperature is exceeded. .

According to the invention, it is proposed to monitor refrigeration and freezing equipment with a device with a container containing in one or more cavities an indicator liquid which freezes or thaws at a specific temperature. Furthermore, the method according to the invention consists in that, by first moving these containers into an initial position, the indicator liquid flows under the influence of gravity into the first volume of the cavity and freezes therein. .

Once the freezing is complete, the container is moved to another position during the monitoring phase, so that the indicator liquid once again flows by gravity into the second volume of the cavity once the melting temperature is exceeded.

Additionally, according to the invention, it is desirable to be able to observe at least one of the two volumes of the cavity in order to ascertain whether the indicator liquid is frozen or thawed.

A device for carrying out the method requires an optical or electrical medium to indicate the position of the liquid in the cavity.

Optical observation is primarily performed using a magnifying lens, prism, or similar medium.

The simple state of the temperature monitoring device according to the invention is that it is rotatable in a fixture, allowing observation of the position of the liquid through a kind of viewing window, and the axis of rotation is not directed in the direction of gravity. It consists of a container with a I mean,
Otherwise, no liquid movement will occur. To achieve a relatively large volume and better viewing, it is desirable to shape the cavity in the container like a U-tube.

For mass production, it is suitable to construct the container as a kind of blister pack filled with the indicating liquid. As is known, in the case of blister packs, at least half of both petri dishes are first formed and then filled and sealed with sealing foil. This manufacturing method has been most appropriately introduced in the pharmaceutical industry when packaging tablets, and is also very rational.

In other embodiments of the invention, the container is made pressurized or covered so that only those parts that are important for discerning function can be viewed.

In addition, if the cavity of the blister pack is provided with a round window in the form of a lens, the respective molten state of the indicator liquid can be easily identified.

Containers of this type can also be easily accommodated in insert pockets that are inserted within the reach of the frozen product.

Since it is not in all cases possible to arrange a plug-in pocket for a tracer of this kind for temperature monitoring on the front plate or wall of the cooling device, according to the invention it is possible to freely deploy the tracer in two positions. It has been proposed to form it as a single part.

It can also be, for example, a prismatic container containing one or more cylindrical cavities containing liquids of various melting temperatures.

A special feature of the invention is a cylindrical tracer, which is placed on one front for freezing and is replaced like an hourglass on the other front for temperature monitoring.

Furthermore, when a plurality of cylinders are combined into one set, in the present invention, the upper portions thereof can be easily formed as optical lenses, and the tracer comes here during freezing.

Example Embodiments of the present invention will be described below with reference to the accompanying drawings.

Figures 1 and 2 illustrate the simplest form of this type of device. The flange (1) and cavity (
A circular hollow body with 2) is shown.

The liquid in Figure 1 is at the bottom of the cavity under the influence of gravity. When the tracer is inserted into the cooling device in this state, the liquid (3) freezes in the shape shown.

When the tracer is rotated after freezing, it will continue to have the appearance shown in FIG. 2 unless the temperature in FIG. 2 exceeds the melting temperature of the indicator liquid (3). But as soon as its critical melting temperature is exceeded, the liquid (
3) is again in the state shown in FIG. After this temperature rise for some time, the cooling device again operates normally and even though the liquid (3) begins to freeze, it maintains the appearance shown in FIG. 1. Therefore, the fact that the critical temperature has been exceeded is clearly visible even after the interruption of operation has been completed.

FIG. 3 shows a side view of the same tracer, ie in a frozen state corresponding to FIG. 2, in which the indicator liquid (3) has migrated to the upper part of the cavity (2).

Another variant of this tracer is illustrated in FIG. 4, in which a septum (4) separates the upper half filled with frozen liquid (3) from the lower cavity (2). In this situation, the electrode connections (5) and (6) are not electrically connected. However, as soon as the liquid (3) melts and flows into the cavity (2), an electrical connection is made for remote indication of the situation.

Figures 5 and 6 show three types of temperatures, more specifically,
A simple example of a blister type for temperatures of -18°C, -12°C and -2°C is shown.

The frozen tracer is shown in FIG. 5, in other words, the tracer stands on end, which can also be seen by looking at the printed temperature display. After freezing, the tracer is rotated 180 degrees until it reaches the position shown in FIG.

Figure 5 shows that the liquid flows through these round windows (7) during freezing.
) has been shown to be able to be identified. Hollow (2
) is hidden by, for example, a cover (8).

Figure 6 also shows how this liquid looks, for example, at -15°C. Inside the window (7), the indicator liquids at -2°C and -12°C remain frozen, but on the other hand, the indicator liquid at -18°C has already melted and moved to the bottom of the cavity. There is.

FIG. 7 is a side view showing the tracer previously described as an extremely flat blister type.

In contrast, FIG. 8 has a cylindrical cavity projecting into the cooling chamber. All other numerals are designated as the same reference numerals as in FIGS. 5 and 6. In the case of Figure 8, the frozen tracking liquid is also shown behind the window (7), but on the other hand, there is a cavity behind the window (10) because the liquid (3) has already melted and descended. (2) can be identified. This figure corresponds to FIG.

In Figures 9 to 13 it is shown how the tracer is suitable for insertion into the stop. These are also finished as a type of blister hack, making them inexpensive and reliable.

FIG. 9 shows the structure of such a tracer. A transparent thermally deformable foil (11) is first made with a cavity (12), then filled with an indicator liquid and finally closed with a sealing foil (13).

Here, as shown in FIG. 10, a plurality of cavities (12), each filled with an indicator liquid (3) of a different melting temperature, can be arranged in a simple manner. In order to better distinguish between different temperatures, it is desirable to dye the indicating liquid differently so that important changes can be identified without looking at the numerical value on the temperature display.

For example, to resemble the color of a traffic light, the liquid for -18°C is "green"(-"go"), and the liquid for -12°C is "yellow".
(= ``Caution''), and the liquid for -2℃ is ``red'' (=
It is preferable to dye it with "Tomare").

In FIG. 10, the tracer is shown in an upright position, or in other words, in a frozen state. After freezing, the tracer is moved to the position shown in Figure 11, where it is clearly identified that the liquid is adapted to melt at a temperature between -18°C and -12°C. Can be done. In other words, the liquid for -18°C has already melted and moved downward under the influence of gravity, whereas the liquid for -12°C and -2°C remains frozen.

In Figure 12, a bayonet pocket (14) on the outside of the freezer drawer is shown.

Here, a window (16
) is provided. In Figure 12, liquid (3) i is still above, that is, the liquid is still frozen. This condition is clearly distinguishable from the outside. This is because the insertion pocket does not cover the entire front of the tracer.

In FIG. 13 a similar plug-in pocket is incorporated directly into the interior space (17) of the cooling device.

Here too, the frozen liquid (3) can be clearly seen.

FIG. 14 schematically shows a tracer as shown in FIG. 9 being confined in an isolation case. Such thermal insulation becomes very important when monitoring the temperature of frozen foods. A particular advantage of the method described in this example is that it allows processes involving frozen foods to be simulated. In other words, to monitor temperature, it is not only important to have an instantaneous temperature display;
The period during which the critical temperature is temporarily exceeded must also be considered.

The following example illustrates the simplest version of this process. That is, in West Germany, for example, when it comes to frozen chicken, -12
It is stipulated by law to be below ℃. The legislative body has clearly stated that exceeding this temperature for any short period of time, from 2 to 5 minutes, has no effect on the quality of the chicken.

However, if -12 DEG C. is exceeded for a short time, a conventional thermometer will unnecessarily display an alarm, for example upon breaking contact with the addition/extraction device.

However, as schematically shown in FIG.
) is delayed in time by the isolating device (18). This isolation device functions so that the liquid will melt after a while even if it is heated above -12°C. The process is therefore also compatible with the reactions of foods that are frozen. This is because it also melts gradually from the outside with a certain amount of time delay. At first only the bag is heated, then the outermost layer, and gradually the heating progresses to the inside of the food.

The time constant representing the delay is naturally adapted to the type of frozen product, and is different for meat and poultry than for vegetables and fruit. Therefore, according to the invention, it is desirable to match the type and thickness of the thermal insulation device to the frozen product.

Although it is self-evident, it must be understood that Figure 14 is a purely schematic diagram and does not represent the actual product.

This is because thermal insulation of the indicator liquid can be achieved by a number of measures. Increasing the wall thickness of the foil, dipping it in insulating enamel, and embedding it in a cover are just a few examples.

In addition to utilizing a blister to contain the indicator liquid, several other embodiments are illustrated in FIGS. 15-21.

In FIG. 15, a prism made of transparent material with three holes is provided, which is filled with liquids having different melting temperatures.

In Figure 15, the triangular prism (20) is a flat surface (21).
placed above. The opening of the hole (19) faces upwards and the hole is approximately half filled with liquid (3). At this time, the hole (19) is closed with a plug (22). 1st
In the position shown in Figure 5 the liquid is frozen. If frozen, the prism (20) becomes a flat surface (23)
be knocked down so that it is facing down. As a result, the liquid (3) will be located at the top. The tracer is now ready for its monitoring capabilities.

Figure 17 shows a side view of a prism of this type with three holes for three temperatures, the temperature states represented there corresponding to -12°C to -2°C. ing. In other words, a liquid for a temperature of -18°C is -12°C.
It melts and flows downward like a liquid for a temperature of ℃, but it has not yet reached the temperature of -2℃, so it becomes a liquid (3℃).
) is still frozen in this hole, and above it.

This type of tracer can be placed anywhere in the cooling device to monitor temperature, and can also be used for monitoring during transport.

The problem of time constants for thermal insulation is easily solved. This is because the hole (19) can be provided anywhere within the prism or on the surface.

This type of tracer, which can be installed freely, is very aesthetically pleasing and can also be finished to suit the purpose. In Figures 18 and 19, the rear lid (25) is also filled with a cylindrical tracer (24) with three holes.
is closed.

Figure 18 shows the monitoring stage after the liquid has frozen. In the illustrated state, the -18°C liquid has already melted. On the other hand, the liquids at -12°C and -22°C are still frozen. In other words, the temperature was at least temporarily between -12°C and -18°C.

FIGS. 20 and 21 exemplarily show a freely installed tracer for three types of liquids, the upper end (26) of which is formed as a lens.

A top view of this tracer is shown in Figure 21, which illustrates some of the other details such as the bridge (27).

The state shown in FIG. 20 is shown in FIG. 18, in other words,
This corresponds to the situation that the lowest temperature liquid has already melted and both remaining liquids are still frozen.

Other methods for improving the optically distinguishable properties of the molten state of an indicator liquid are illustrated in FIGS. 22 and 23. Here the tracer is shown as a kind of blister pack for two temperatures and is provided with a foil (11) with a lenticular round window (28), which round window (29) in the wall (30). ), so it can be easily identified from the outside. One shaft (31) and one adjustment knob (32) are attached to the foil (11). The spring (33) together with the round window (28) constantly presses the tracer foil (11) through the window (29).

To use this tracer, both these liquids for -18°C and -12°C are refrozen and then the round window (
28) is transferred into the window (29) of the plate (30).

FIG. 23 shows the temperature monitoring state in the following situation, ie, the liquid for -18°C has already melted and the liquid for -12°C is still frozen.

The embodiment of Figure 24 contains indicator liquids that have equal melting points but react at different rates due to different insulation conditions in holes of varying distances to the surface. Therefore, it is particularly suitable for testing how long an interruption lasts.

Figure 24 shows three cavities (35), (36) and (37) with tracer (
34) is schematically shown.

In this case these cavities are filled with liquid of equal melting temperature.

The liquid in the cavity (37) reacts relatively quickly to excess temperature. On the other hand, the trace fluid in cavities (36) and (35) reacts only with a considerable delay.

From the numerous embodiments it can be seen that the possibilities of application, ie the configuration of the method and of the apparatus for carrying out the method, are diverse. Therefore, some of the cited examples must be understood as a part of them, and many other examples are also included as specific configurations according to the present invention.

In addition, this also includes the advantage that the device is not limited to a specific installation angle, as long as the axis of rotation when installing the device after freezing does not coincide with the direction of gravity.

This is because gravity is used as the only directing medium.

All examples presented as blisters are intended to be interchangeable with plastic or glass products, and vice versa. Further, the display can be converted into a signal by remote transmission using any commonly used means.

There are no particular design limitations when forming a free-standing tracer according to the invention. This also applies to shape, color, insulation and handling.

It is also an embodiment of the invention to configure the plug-in part with a direct or insulated thermal coupling to be inserted into the temperature monitoring point.

[Brief explanation of the drawing]

The figures show an embodiment of the present invention; FIG. 1 is a front view of the indicator liquid before freezing, FIG. 2 is a front view of the inverted state after freezing, and FIG. 3 is a side view thereof. FIG. 4 is a side view of another example, FIGS. 5 and 6 are front views showing still another example in use before and after freezing the indicator liquid, respectively, and FIG. 7 is a side view thereof; FIG. 8 is a side view of still another example, FIGS. 9 and 10 are side views and front views of another example of the indicator liquid in its state before freezing, and FIG. 11 is its use state after freezing. 12 to 15 are side views of still other examples that are different from each other, FIG. 16 is a side view of the example in FIG. 15 in an inverted state after freezing, and FIG. 17 is a use of still another example. 18 and 19, and FIGS. 20 and 21 are front views and side views of still other examples, and FIGS. 22 and 23 are side views and front views of still other examples. FIG. 24 is a front view of still another example. (1)...Flange (2)...Cavity (3)...Indicator liquid (7)...Round window (10)... ...Window (12) ...Cavity (13) ...Tracer (14) ...Pocket pocket (16) ...
... Window (20) ... Triangular prism (24) ... Tracer (29) ... Window (35), (36), (37) ...・Cavity (hereafter
top) Fl(:y 7B Fl(y 20Fl
(:y '19 Fl(y 21FIG
22 Fl (323 Fl (32
4

Claims (16)

[Claims] (1) In a method for monitoring the temperature of refrigerated and frozen products,
When a container with one or more cavities, each not completely filled with an indicating liquid that freezes or thaws at a particular temperature, is transferred to the initial position during freezing, the indicating liquid The liquid begins to freeze in a first part within the cavity under the influence of gravity, and once freezing is complete, the container is then moved to another position and the liquid is again subjected to the influence of gravity as it thaws. flow into the second portion of the cavity to indicate that the melting temperature has been exceeded. 2. The method of claim 1, wherein the container is provided with an indicator liquid that is at least partially thermally insulated from the cooling space to be monitored. 3. The method of claim 1, wherein at least one of both parts of the cavity can be observed. 4. The method according to claim 1, further comprising an optical or electrical medium for indicating the position of the indicating liquid in the cavity. 5. The method according to claim 4, wherein the optical medium is a lens or a prism. (6) Any one of claims 1 to 5, characterized in that the hollow container rotatable in the stopper is provided with a kind of viewing window, the axis of rotation of which is not directed in the direction of gravity. Apparatus for carrying out the method described in 7. Device according to claim 6, characterized in that the cavity in the container is formed as a type of U-tube. 8. Device according to claim 1, characterized in that the container is formed as a blister pack. 9. The device of claim 8, wherein the container is pressurized or covered. (10) Claim 8 or 9, wherein the blister pack is formed with a round window in the shape of a lens.
The device described in. (11) Claim 1, wherein the container is formed as a component that can be freely installed in two positions.
8. The device according to any one of 7. 12. The device of claim 11, wherein the container is a prism having one or more cavities. (13) The device according to claim 11, wherein the container has a cylindrical shape or a truncated cone shape. 14. The device according to claim 11, wherein the container is composed of a plurality of cylindrical units whose upper parts are formed as optical lenses. (15) The device according to any one of claims 1 to 7, characterized in that the container is provided with an insertion pocket that is inserted into the area of influence of the frozen product. (16) A plurality of cavities contain an indicator liquid of equal melting temperature, but the cavities have varying thermal insulation with respect to the cooling chamber to be monitored. 8. The device according to any one of 1 to 7.