EP2023743A1

EP2023743A1 - Method for the operation of a container suitable for freezing the content thereof, and ice cream maker

Info

Publication number: EP2023743A1
Application number: EP07729333A
Authority: EP
Inventors: Jutta Schomacher
Original assignee: Vorwerk and Co Interholding GmbH
Current assignee: Vorwerk and Co Interholding GmbH
Priority date: 2006-05-23
Filing date: 2007-05-21
Publication date: 2009-02-18
Also published as: MX2008014951A; RU2008150864A; WO2007135130A1; TW200808195A; DE102006024031A1; CN101437408A

Abstract

The invention relates to a method for operating a container (3) that is suitable for freezing the content (13) thereof as well as an ice cream maker (1). Peltier elements (16) which are actively cooled on the hot side thereof by means of an actively chilled coolant circulating in an independent circuit (17) are disposed in a wall of the container (3) so as to generate cold. In order to further improve a method of said type particularly in respect to actively chilling the coolant, the coolant is actively chilled by having the coolant exchange heat with a latent heat accumulator (20). In order to obtain a desired freezing temperature in the inventive ice cream maker while keeping the amount of energy required as low as possible, a cold reservoir is associated with the coolant circuit in the form of a latent heat accumulator (20).

Description

Method for operating a container suitable for freezing its contents and ice making device

The invention initially relates to a method for operating a container suitable for freezing its contents, wherein in a wall of the container for cooling Peltier elements are arranged, which are actively cooled on its hot side by means of circulating in a separate circuit coolant, which in turn actively cooled becomes.

Methods of the type in question are known. During cold generation / ice production with Peltier elements, a cold and a hot side are created on the element. The resulting cooling capacity is directly dependent on the heat dissipation via the hot side of the element. This heat dissipation is usually done via heat sink and / or fan and / or a water cooling. Peltier elements work effectively with small temperature differences between the hot and the cold side. In order to achieve greater temperature differences or a greater cooling capacity between hot and cold side, it requires a cooling of the hot side. The temperature differences of more than 30 K necessary for ice production are achieved, for example, with water cooling and additional heat exchangers in the form of a fan on the hot side of the elements. In this regard, reference is made to EP 0 133 844 Bl. This patent shows and describes a device for ice cream, in particular in the form of a household appliance, in which according to a first embodiment, the cold generating Peltier elements are actively cooled backwards through a coolant circuit. This coolant circuit has a heat exchanger which cooperates with a motor-driven fan.

In view of the described prior art, a technical problem of the invention is seen as a method of the present in question Type in particular with regard to the active cooling of the coolant to further improve.

This problem is initially and essentially solved in that the active cooling of the coolant is carried out by heat exchange of the coolant with a latent heat storage. According to this method according to the Invention, the efficiency for icing of a content provided in a suitable container is improved. Each to be overcome temperature differences are kept relatively small. Both the Peltier technology and the latent heat storage technology are very well suited for cooling over small temperature differences. Latent heat storage systems use the energy from the phase change. The storage material releases thermal energy at a constant temperature over the entire melting process, which in turn causes a constant rearward, active cooling of the Peltier elements via the cooling medium cooled thereby. This is especially true over a longer period over which latent heat storage are able to deliver a constant temperature. In addition, by means of the envisaged latent heat accumulator and its ability to store heat energy over several hours, it is possible to prepare a device operating with the method according to the invention, in particular an ice cream device for the preparation of ice cream for operation. The coolant circuit ensures that the hot side of the Peltier elements is cooled continuously and for a long time with a preferably minus-grade liquid. As a result of the large temperature difference created between the hot side of the Peltier elements and the coolant, a much greater amount of heat can be removed from the hot side of the Peltier elements and, in turn, a negative temperature sufficient for ice formation can be achieved on the cold side of the Peltier elements. In the known from the prior art water cooling, the coolant has ambient temperature and warms relatively quickly. With increasing warming of the cooling water sinks the temperature difference to the ambient temperature, which is necessary to transport amounts of heat.

The subject matter of the further claim is explained below with reference to the subject matter of claim 1, but may also be significant in its independent formulation.

Thus, it is preferably provided that the latent heat storage by means of the cooling circuit, which is associated with a separate Peltier element, is cooled. As a result of this embodiment, the Peltier technology is also used for charging the latent heat storage. For this purpose, as preferred, a separate Peltier element can be provided. A solution is also conceivable in which the Peltier element which cools the container serving for ice making serves at the same time as the charge of the latent heat store. In order to achieve a low-loss charge of the latent heat accumulator, a separate Peltier element is provided which acts indirectly on the latent heat accumulator via the cooling circuit. For this purpose, the entire cooling system is more preferably divided into two stages. In a first stage, the latent heat storage is, for example, cooled down with Peltier technology over a period of four hours, during which the cooling cycle is preferably reduced to a minimum during this first stage. In particular, the heat exchanger area between the cooling circuit and the Peltier elements to be assigned to the ice preparation is excluded during this first stage. To cool down the latent heat storage very little energy is needed. Preferably, the container in which the latent heat storage is located so that no heat energy is lost to the environment. If the latent heat storage is loaded, then the complete cooling circuit can be opened and the icing process can begin. The coolant is preferably kept in circulation by a pump, more preferably by an electric pump. The invention further relates to a Eiseleisbereitungs- device with a suitable for icing its contents container, whose wall for cooling a (first) Peltier element is assigned, said Peltier element is actively cooled on its hot side by means of a heat transfer medium, wherein further the heat transfer medium in a separate cooling circuit is performed.

A Eiseisbereitungs- device of the type in question is known from the aforementioned EP 0 133 844 Bl.

In view of the known prior art, a technical problem of the invention is seen in such a device of the type in question to design improved so that at the lowest possible energy target temperature for icing of the container contents is reached, which is well below freezing.

This problem is solved first and foremost by the subject matter of claim 3, wherein it is based on the fact that the cooling circuit is associated with a cold reservoir in the form of a latent heat accumulator. According to this embodiment, a Eiseleisbereitungs- device is created whose pervious Peltier element on the back, that is kept on the hot side by means of the cooling circuit at a preferably constant temperature. The cold reservoir is formed by a latent heat storage, which was preloaded in a separate process. Such a memory can transmit a constant temperature over a longer period, so in the present case to the coolant. This is promoted in a closed pipe system, which cooling tube passes through the latent heat storage or the heat storage material for heat exchange. Alternatively, an arrangement may be provided, in which the cooling line on an outer wall the memory is passed. In the usual way, such cooling pipes are arranged spirally for heat exchange, so as to provide a sufficiently large surface area.

The subjects of the further claims are explained below in relation to the subject matter of claim 3, but may also be of importance in their independent formulation.

The latent heat storage is preferably loaded via a Peltier element. This may be the same Peltier element which is associated with the wall of the container suitable for icing its contents. In order to achieve an increased efficiency of the device is provided that the cooling circuit is assigned a separate Peltier element for charging the latent heat storage. This is energized only to charge the latent heat storage, while the activation of the first Peltier element is performed only for icing of the container contents. As a result of this embodiment, due to the low power consumption of Peltier elements, the latent heat accumulator can be charged at relatively low energy, which thereafter emits a constant temperature to the cooling circuit over a relatively long period of time. It is further proposed that the cooling circuit for the time separation of the charge of the latent heat storage of the ice cream preparation from the cooling of the first Peltier element can be decoupled. This further contributes to the increase in the efficiency of the device. During the charging process of the latent heat accumulator, the coolant does not flow around the container area with the first Peltier elements provided here. The cooling circuit for charging the latent heat storage is kept as small as possible to counteract losses. The coolant is used for heat transfer between the other Peltier element and the latent heat accumulator, wherein further the further Peltier element does not necessarily have to act directly on the coolant or the pipes receiving the coolant. Also an indirect action is conceivable, for example, with the interposition of another circuit. If the latent heat storage device is charged, the further Peltier elements are switched off and the large cooling circuit which includes the sleeve-like cooling sections of the container having the first Peltier elements is unlocked.

The storage material of the latent heat storage is preferably based on paraffin or salt. The liquefaction / solidification temperature of the latent heat storage medium is preferably chosen below 0 ° C, ideally the liquefaction temperature and the solidification temperature are the same. By all means, these temperatures may also be different, albeit only by a difference of a few degrees C. For example, here the solidification temperature can be minus 8 ° C, while a liquefaction is already achieved at minus 5 ° C. In general, the temperature is between minus 1 ° C to minus 10 ° C, so ideally at minus 5 ° C.

The efficiency of the Peltier elements for generating cooling capacity in the area suitable for icing its contents container is considerably improved according to the proposed invention. The ice making process is accelerated. The cold reservoir (latent heat storage) can be recharged at any time. The advantages of a latent heat storage and the Peltier elements are advantageous and low energy combined. By cooling the hot side of the container-side Peltier elements with preferably minus 5 ° C cold coolant (preferably water-glycol mixture), the size and weight of the device over conventional devices are greatly reduced. The cooling capacity of the Peltier elements can be optimally used as the hot side is optimally cooled. The heat loss amounts are kept small, with the cooling of the Peltier elements also taking place at constant temperature. The invention with reference to the accompanying drawings, which is merely an embodiment, explained in more detail. It shows:

1 is a schematic side view of a Eiseisbereitungs-

Device in the form of a food processor;

2 shows a partially sectioned illustration through the base area of a container suitable for freezing its contents and the receptacle area of the device which surrounds the container base in the manner of a sleeve;

Fig. 3 shows a schematic representation of the device for icing a container contents.

With reference to FIG. 1, an ice-cream preparation device 1, which is part of a food processor 2 in the exemplary embodiment shown, is shown and described.

With regard to the food processor 2, it is such as is known, for example, from DE 10210442 A1. The content of this patent application is hereby incorporated in full into the disclosure of the present invention, also for the purpose of including features of this patent application in claims of the present invention.

Accordingly, the illustrated food processor 2 a container 3 can be assigned. This is placed in a receptacle 4 of the food processor 2. In the container 3, which is formed as a mixing vessel, the agitator bottom is associated with an agitator 5, which arranged on a in the kitchen machine 2 below the receptacle 4, not shown Electric drive is operated.

The control, in particular speed control of the agitator 5 is made via a control panel 6 of the food processor 2. Further functions can be controlled via this control panel, for example, a heating of the container 3 in the region of its bottom, thus, for example, for cooking food in the container 3 or, as explained further, for cooling up to icing of the contents of the container.

The container 3 has a handle 7. The upwardly facing container opening can be closed by a removable cover 8.

The receptacle 4 is essentially formed of two oppositely arranged, tower-like jaws 9. The upper free end portions of these jaws 9 form shoulders 10. In these shoulder areas locking elements 11 are provided in the form of horizontal grooves. These act together with corresponding counter-elements in the form of radially projecting fingers 12 of the lid 8. After inserting the container 3 in the receptacle 4, the lid 8 is placed and locked by screwing the fingers 12 in the groove-like locking elements 11 of the shoulders 10, wherein further the retracting fingers 12 provide a release of the electrical functions, in particular a release of the agitator 5.

The food processor 2 is further designed for ice cream, for which purpose the same container 3 can be used. Alternatively, a container 3 with heating integrated in the container bottom may also be provided for the usual food preparation, optionally with heat being influenced, while for ice cream preparation a container 3 is preferred which does not have this bottom heating. The agitator 5 is exchanged for ice cream preparation against a corresponding agitator, so in particular against a scraper-like blades exhibiting.

In order to freeze the contents 13 of the container 3, a refrigeration device 14 is initially provided in the cuff-like manner the base region of the container 3 comprehensive portion of the receptacle 4. This consists of several sleeve-like in the receptacle 4, the base portion 15 comprehensively arranged Peltier elements 16. These are electrically controlled.

Depending on the current and current direction, the upper regions of the Peltier elements cool, while the lower ones heat up. The stream thus "pumps" heat from one side to the other and creates a temperature difference between the surfaces.

As an alternative to the arrangement of the Peltier elements 16 in the receptacle 4, these can also be provided in the receptacle 4 directly in the base region of the receptacle 3, even with corresponding electrical contacting.

In order to achieve a sufficient temperature difference between the cold side and the hot side of the Peltier elements 16, these are rearwardly, d. H. on the hot side, the container 3 away actively cooled. For this purpose, a cooling circuit 17 is provided. A water-glycol mixture flows through a pipeline 18 which produces a circulation. A section of this pipeline 18 comprises the region having the Peltier elements 16 in the manner of a sleeve, for the large-area cooling of the same.

The cooling circuit 17 is driven by an electric pump 19th Cooling undergoes the circulating mixture through a provided, a cold reservoir bidding latent heat storage 20, through which the tube power is 18 guided helically. The latent heat storage 20 is double-walled and serves as a heat exchanger. The storage material may be based on paraffin or salt.

To start up the Eiseiszubereitungs- device 1 is a preparation in the form of a loading of the latent heat storage 20 is required. The energy is stored in the latent heat storage by means of Peltier technology, for which purpose further Peltier elements 21 are provided. These are arranged facing with their cold side of the pipe wall of the cooling circuit 17, while the hot side are provided with cooling fins 22.

The entire cooling system is divided into two stages. In a first stage, the latent heat storage 20 is cooled down over a period of about four hours using Peltier technology, for which purpose the Peltier elements 21 are activated. During this charging phase, the cooling cycle area which concerns the first Peltier elements 16 will not pass, for which purpose a bypass line 23 is provided. This is opened by means of electrically actuated valves 24, while the path over the Peltier elements 16 is blocked via further valves 25. Accordingly, very little energy is needed to cool down and charge the latent heat storage 20. The container in which the latent heat storage 20 is located is insulated, so that no heat energy is lost to the environment.

Has the entire latent heat storage content reaches a target temperature of preferably minus 5 ° C. Thus, the entire device 1 is ready for ice cream. This process is started, as also previously the charging process of the latent heat storage 20, via the control panel 3, wherein initially under closing the valves 24 and opening the valves 25 of the large cooling circuit is released. With constant stirring of the contents 13 by means of the agitator 5, the desired icing takes place.

By means of the heat exchanger, formed by the latent heat storage 20, the circulating water-glycol mixture is maintained at a constant temperature of minus 5 ° C. Accordingly, the hot side of the supply-side Peltier elements 16 is cooled with the minus-5 ° C cold coolant mixture, so that 16 sets a temperature of minus 10 to minus 20 ° C on the cold side of the Peltier elements. Due to the fact that the hot side of the Peltier elements 16 are kept constant at -5 ° C. by the latent heat accumulator 20, optimum cooling takes place with a small temperature difference. The content to be frosted 13 thus has - taking into account temperature losses due to the heat transfer / heat losses - a minimum temperature of minus 5 ° C.

Accordingly, for example, ice cream preparation can be achieved while supplying low energy at a constant temperature over a longer period of time.

By reversing the polarity of the Peltier elements 16 and the concomitant exchange of cold and hot side, they can in a further embodiment also for heating a content received in the container 3 this content. For example, in particular for keeping food warm, which is particularly the case when the device is arranged in a food processor 2 as shown.

All disclosed features are essential to the invention. The disclosure content of the associated / attached priority documents (copy of the prior application) is hereby also incorporated in the disclosure of the application. also included for the purpose of including features of these documents in claims of the present application.

Claims

1. A method for operating a for icing its contents (13) suitable container (3), wherein in a wall of the container (3) for cooling Peltier elements (16) are arranged, which are actively cooled on its hot side by means of a separate circuit (17) circulating coolant, which in turn is actively cooled, characterized in that the active cooling of the coolant by heat exchange of the coolant with a latent heat storage (20) is made.

2. The method of claim 1 or in particular according thereto, characterized in that the latent heat accumulator (20) by means of the cooling circuit (17) to which a separate Peltier element (21) is assigned, is cooled.

3. Eiseisbereitungs- device (1) with a suitable for icing its contents container (3), whose wall for cooling a (first) Peltier element (16) is assigned, said Peier animal element (16) on its hot side by means of a heat transfer medium active is cooled, wherein further the heat transfer medium in a separate cooling circuit (17) is guided, characterized in that the cooling circuit is associated with a cold reservoir in the form of a latent heat accumulator (20).

4. Apparatus according to claim 3 or in particular according thereto, characterized in that the cooling circuit (17) is associated with a separate Peltier element (21) for charging the latent heat accumulator (20).

5. The device according to one or more of claims 3 to 4 or in particular according thereto, characterized in that the cooling circuit (17) for temporal separation of the charge of the latent heat accumulator (20) before the ice cream preparation of the cooling of the first peier animalelementes (16) decoupled is.

6. Device according to one or more of claims 3 to 5 or in particular according thereto, characterized in that the liquefaction / solidification temperature of the latent heat storage medium (20) is selected below 0 ° C.

7. Device according to one or more of claims 3 to 6 or in particular according thereto, characterized in that the temperature is selected between minus 1 ° C to minus 10 ° C.