METHOD FOR THE OPERATION OF AN APPROPRIATE CONTAINER FOR THE FREEZING OF ITS CONTENT AND DEVICE FOR THE PREPARATION OF ICE CREAM DESCRIPTION OF THE INVENTION
The invention relates firstly to a method for the operation of a container suitable for freezing its contents, Peltier connections being arranged in the wall of the container for the generation of cold which are actively cooled on its hot side by means of a circulating cooling agent in its own circulation which in turn is actively cooled. The methods of the type in question are known. In cold production / production of ice cream by means of Peltier joints, a cold and a hot side are generated in the joint. The cooling power generated directly depends on the dissipation of heat through the hot side of the joint. This heat dissipation is usually carried out through a cooling body and / or fan and / or water cooling. Peltier joints work effectively with small temperature differences between the hot and cold sides. To achieve higher temperature differences, respectively, a higher cooling power between the hot and cold side, it is necessary to cool the hot side. The temperature differences necessary for the production of ice cream, greater than 30K, are achieved, by way of example, by cooling with water and heat exchanger in the form of a fan on the hot side of the joints. Reference is made to EP 0 133 844 Bl. This patent publication shows and describes a device for the production of edible ice cream, in particular in the form of a domestic appliance, in which, in a first embodiment, the Peltier junctions used for the production of cold are cooled in the back by a circulation of a refrigerant. This circulation of refrigerant has a heat exchanger that acts in collaboration with a motor-driven ventilation. In consideration of the state of the art described there is a technical problem of the invention in perfecting a method of the type in question in particular in terms of the active cooling of the refrigerant. This problem is solved first and essentially, because the active cooling of the refrigerant is carried out by changing the heat of the refrigerant using a latent heat accumulator. Thanks to this inventive method, the degree of effectiveness for freezing an expected content in an appropriate container is improved. The temperature differences that must be overcome in each case remain relatively small. Both the Peltier technique and the latent heat accumulation technique are very suitable for cooling by small differences in temperature. The latent heat accumulators take advantage of the phase change energy. The material of the accumulator emits thermal energy during the whole process of melting at a constant temperature, which causes, in turn, a constant active cooling at the rear of the Peltier junctions for the refrigerant, cooled thereby. This in particular during an extended period in which the latent heat accumulators are capable of emitting a constant temperature. Furthermore, the possibility is offered by accumulating the latent heat foreseen and its property of accumulating thermal energy for several hours to prepare a device that works with the inventive method, in particular an edible ice-cream device for the preparation of edible ice cream. The coolant circulation ensures that the hot side of the Peltier joints is continuously and for an extended time cooled by a liquid that is preferably at minus degrees. The large temperature difference, generated in this way, between the hot side of the Peltier joints and the coolant allows the dissipation of a much greater amount of heat from the hot side of the Peltier joints and, with this, a temperature below zero sufficient for the preparation of ice cream is also achieved on the cold side of the Peltier joints. In the water cooling known from the state of the art, the refrigerant has room temperature and is heated relatively quickly. As the heating of the cooling water increases, the difference in temperature at room temperature, which is necessary to transport quantities of heat, is reduced. The object of the additional claim is explained below with reference to the object of claim 1, however, it may also have meaning in its independent wording. Thus, it is preferably provided that the latent heat accumulator is cooled by the cooling circulation for which a separate Peltier connection is associated. Thanks to this design, it is possible to take advantage of the Peltier technique simultaneously to charge the latent heat accumulator. For this purpose, a separate Peltier connection can be provided, as preferred. A solution is also conceivable in that the Peltier connection, which cools the container for preparing the ice cream, serves, in a temporarily displaced manner, also for loading the latent heat accumulator. In order to achieve a low loss load of the latent heat accumulator, a separate Peltier connection is provided which acts indirectly through the cooling circulation in the latent heat accumulator. For this purpose, it is also preferably provided to separate the entire cooling system in two stages. In a first step, the latent heat accumulator is cooled, for example, during a period of four hours by the Peltier technique, the cooling circulation being preferably reduced to a minimum during this first stage. In particular, the heat exchanger zone between the cooling circulation and the Peltier connections that must be assigned to the ice cream preparation is excluded during this first stage. To cool the latent heat accumulator, very little energy is required. Preferably, the container in which the latent heat store is located is insulated, so that no thermal energy is lost to the environment. As soon as the latent heat accumulator is loaded, the complete cooling circulation can be opened and the freezing process can be started. The refrigerant is kept in circulation, preferably by means of a pump, and it is further preferred that it be an electric pump. The invention also relates to a device for the preparation of edible ice cream comprising a container suitable for freezing its contents, to whose wall is assigned a (first) union, Peltier for the generation of cold, being this first union of Peltier actively cooled on its hot side by a heat transfer medium, the heat transfer medium being further conducted in a separate cooling circulation. An edible ice cream preparation device of the type in question is known from EP 0 133 844 Bl mentioned initially. In consideration of the known state of the art a technical problem of the invention is seen in perfecting a device of the type in question in such a way that a defined temperature, which is clearly below the freezing point, is achieved for the freezing of the content of the container with as little energy as possible. This problem is solved first and essentially by the object of claim 3, having as an approach that a cooling tank in the form of a latent heat accumulator is associated with the cooling circulation. Thanks to this design, an edible ice cream preparation device is created whose Peltier connection on the side of the container is maintained at a preferably constant temperature by the cooling circulation at its rear, that is, on the hot side. The cold deposit is formed by a latent heat accumulator that was previously charged in a separate process. An accumulator of this type can transmit a constant temperature for a prolonged period, in the present case to the refrigerant. This is transported in a closed pipe system, with this cooling tube passing through the latent heat accumulator, respectively, the heat storage material for heat exchange. It is also possible to provide, as an alternative, an arrangement in which the cooling pipe passes next to an external wall of the accumulator. As usual, these cooling pipes for heat exchange are arranged in a spiral to provide a sufficiently large surface area. The objects of the other claims are explained below with reference to the object of claim 3, but may also have meaning in their independent wording. The latent heat accumulator is preferably charged by means of a Peltier connection. This can be the same Peltier connection that is associated with the wall of the appropriate container for the freezing of its contents. To achieve a higher performance of the device, it is envisaged to associate a separate Peltier connection to the cooling circulation to charge the latent heat accumulator. This receives electric current to charge the latent heat accumulator, while the activation of the first Peltier connection is made only to freeze the contents of the container. Thanks to this design it is possible to charge the latent heat accumulator with relatively little energy, thanks to the low power requirement of the Peltier junctions, and the latter then emits a constant temperature to the cooling circulation for a relatively long period. It is further proposed that the cooling circulation can be decoupled from the first Peltier junction to separate the charge of the latent heat accumulator from the preparation of edible ice cream over time. This also helps to increase the performance of the device. The refrigerant does not flow during the process of charging the latent heat accumulator in the area of the container with the first Peltier connections provided there. The cooling circulation to charge the latent heat accumulator is kept as small as possible to counteract the losses. The coolant serves to transport heat between the other Peltier connection and the latent heat accumulator, and it is not necessary that the additional Peltier connection act directly on the coolant, respectively, the pipe that houses the coolant. It is also possible to imagine an indirect influence, v. gr. , inserting another circulation. Once the latent heat accumulator is charged, the additional Peltier connections are disconnected and the large cooling circulation surrounding the cooling sections of the container comprising the first Peltier joints in the form of a sleeve is switched on. The accumulation material of the latent heat accumulator is preferably based on paraffin or salt. The liquefaction / solidification temperature of the latent heat storage medium is preferably selected below 0 ° C, the liquefaction temperature and the solidification temperature being ideally the same. But of course it is also possible that these temperatures are different, even for a difference of only a few degrees C. It is possible, for example, that the solidification temperature is located at minus 8 ° C, while achieving a liquefaction already at minus 5 ° C. The temperature is generally between minus 1 ° C and minus 10 ° C, ideally preferred at minus 5 ° C. The performance of the Peltier junctions for the generation of cold power in the region of the appropriate container for the freezing of their content is considerably improved thanks to the proposed invention. The ice cream production process is accelerated. The cold storage tank (latent heat accumulator) can be recharged at any time. It is combined advantageously and energetically convenient the advantages of a latent heat accumulator and Peltier joints. Thanks to the cooling on the hot side of the Peltier connections on the side of the container with a coolant preferably with a cold of less than 5 ° C (preferably a mixture of water and glycol) the construction size and the weight of the device are drastically reduced. Comparison with conventional devices. The cooling power of the Peltier joints can be optimally utilized, since the hot side is cooled optimally. The amounts of heat loss are kept small, and cooling of the Peltier joints at a constant temperature is also carried out. The invention is explained more closely below by means of the attached figures 1 to 3, which represent only one embodiment. Shown: Fig. 1 in a schematic side view an edible ice cream preparation device in the form of a cooking appliance; Fig. 2 a representation partially sectioned by the base region of a container suitable for freezing its contents and the housing region of the device that wraps the container of the container in the manner of a sleeve; Fig. 3 in a schematic representation the device for freezing a container contents. A device 1 for preparing edible ice cream which is, in the illustrated embodiment, part of a kitchen appliance 2 is represented and described first with reference to FIG. As for the kitchen appliance 2, it is the type that is known, for example, from DE 10210442A1. The content of this patent application is integrated by this mention in its full contents to the manifestation of the present invention, also for the purpose of including features of that patent application in the claims of the present invention. According to this, a container 3 can be associated to the kitchen appliance 2 shown. This is placed in a housing 4 of the kitchen appliance 2. In the container 3 that is configured as a blender, a stirring mechanism 5 is provided on the floor of the blender, which is driven by an electric motor arranged in the kitchen appliance 2 below the housing 4, not shown in detail. The control, in particular the control of the revolutions per minute of the stirring mechanism 5, is carried out by the control field 6 of the kitchen appliance 2. This control field allows controlling other functions, like this, v. gr., a heating of the container 3 in the region of its floor, thus, v. gr. , for cooking food in the container 3 or, as explained below, for cooling or even freezing the contents of the container. The container 3 has a handle 7. The opening of the container facing upwards can be closed by a removable cover 8. The housing 4 is essentially formed by two tower-shaped jaws 9 arranged opposite each other. The regions of the free upper end of these jaws 9 form heels 10. In the regions of these heels there are provided locking elements 11 in the form of horizontal grooves. These act in collaboration with complementary elements in the form of fingers 12 of the lid 8 projecting radially. After inserting the container 3 into the housing 4 the lid 8 is inserted and locked by rotating the fingers 12 so that they are inserted into the slot-shaped locking elements 11 of the beads 10, the incoming fingers 12 also producing a release of electrical functions, in particular a release of the stirring mechanism 5. The kitchen appliance 2 is also designed for the preparation of edible ice cream, the same container 3 can be used for this purpose. As an alternative it is possible to provide for the preparation of conventional food, optionally with application of heat, a container 3 with heating integrated in the floor of the container, while a container 3 that does not have this floor heating is preferred for the preparation of edible ice cream. . The stirring mechanism 5 is changed for the preparation of edible ice cream by an appropriate stirring mechanism, in particular by scraper-shaped blades. In order to freeze the contents 13 of the container 3, provision is first made in the region of the section of the housing 4 that surrounds the base region of the sleeve-shaped container 3 with a device 14 for producing cold. This consists of several Peltier joints 16 arranged in the housing that surrounds the base section 15 in the form of a sleeve. These are electrically controlled. Depending on the power of the current and the direction of the current the upper regions of the Peltier junctions are cooled, while the lower regions are heated. The current therefore "pumps" the heat from one side to the other and produces a temperature difference between the surfaces.
As an alternative to the arrangement of the Peltier joints 16 in the housing 4, these can also be provided directly in the base region of the container 3 if there are corresponding electrical contacts in the housing 4. In order to achieve a sufficient temperature difference between the cold side and the hot side of the Peltier joints 16, these are actively cooled in their rear part, that is, on the hot side, facing away from the container 3. For this purpose, a cooling circulation 17 is provided. A mixture of water and glycol flows through a pipe 18 that offers circulation. A section of this pipe 18 surrounds the region comprising the Peltier junctions 16 in the manner of a sleeve for a cooling of large area thereof. The cooling circulation 17 is driven by an electric pump 19. The circulating mixture is cooled by a latent heat accumulator 20 which offers a cold deposit, by which the pipe 18 passes spirally. The latent heat accumulator 20 is configured with a double wall and correspondingly serves as a heat exchanger. The accumulation material may be based on this paraffin or salt. To start the operation of the edible ice cream preparation device 1, a preparation in the form of a charge of the latent heat accumulator 20 is required. The accumulation of energy to the latent heat accumulator is carried out using the Peltier technique, for which additional Peltier junctions 21 are provided. These are arranged with their cold side facing the walls of the pipe of the cooling circulation 17, while the heat side is provided with cooling lamellas 22. The entire cooling system is subdivided into two stages. In a first step, the latent heat accumulator 20 is cooled for a period of about four hours by the Peltier technique, for which the Peltier junctions 21 are connected. During this loading stage there is no circulation in the region of the cooling circulation associated with the first Peltier junctions 16, for which a bypass pipe 23 is provided. This is opened through electric control valves 24, while the route through the Peltier junctions 16 is closed by other valves 25. Correspondingly, very little energy is required to cool and charge the latent heat accumulator 20. The container in which the latent heat store 20 is located is insulated, so that no thermal energy is lost to the environment.
Once the entire content of the latent heat accumulator has reached a defined temperature of preferably less than 5 ° C, then the entire device 1 is ready for the preparation of the edible ice cream. This event is initiated by the control field 3 as well as the charging event of the latent heat accumulator 20 above, the large cooling circulation being first released by closing the valve 24 and opening the valves 25. While stirring the continuously, by the stirring mechanism 5, the desirable freezing is carried out. By means of the heat exchanger, formed by the latent heat accumulator 20, the mixture of water and glycol in circulation is continuously maintained at a temperature of minus 5 °. Correspondingly, the hot side of the Peltier joints 16 on the side of the container is cooled with the cold coolant mixture of minus 5 ° C, so that a temperature of minus 10 is set on the cold side of the Peltier joints 16. at minus 20 ° C. Because the hot side of the Peltier junctions 16 is preserved at less than 5 ° C constants by the latent heat accumulator 20, optimal cooling is performed with a small temperature difference. The content 13 to be frozen has, therefore, a minimum temperature of minus 5 ° C, taking into account temperature losses due to the heat transition / heat losses. Correspondingly, a preparation, for example, of edible ice cream can be achieved with low energy supply for a prolonged period at constant temperature. By reversing the poles of the Peltier joints 16 and, together with this, the exchange of the cold and hot side, these can serve -in another conditioning- also for the heating of a content housed in the container 3. In particular to keep warm to food, which is offered in particular when using the device in a kitchen appliance 2, as depicted. All the manifested characteristics are essential for the invention (by itself). In the manifestation of the application, the manifested content of the associated priority documents / annexes is also integrated in its full content, also with the purpose of incorporating characteristics of these documents in the claims of the present application.