US20080184986A1

US20080184986A1 - Heat Accumulator Device And Cooking Appliance Comprising A Heat Accumulator Device Of This Type

Info

Publication number: US20080184986A1
Application number: US11/662,688
Authority: US
Inventors: Peter Kohlstrung
Original assignee: Rational AG
Current assignee: Rational AG
Priority date: 2004-09-13
Filing date: 2005-09-07
Publication date: 2008-08-07
Also published as: DE102004044121A1; EP1789730B1; DE502005003240D1; WO2006029597A1; DE102004044121B4; EP1789730A1

Abstract

A heat accumulator device for a cooking appliance, comprising a housing, which can be sealed by a door and contains an interior section with a cooking chamber, at least one heating device for generating hot air and/or steam from a steam generator, and a fan device for circulating hot air and/or steam in the cooking chamber. The heat accumulator device comprises at least one accumulator container, which at least temporarily holds a medium that is at least partially fluid above a specific temperature and at least one heat exchanger, into which at least part of the medium can be pumped at least temporarily and which extends into the interior section and the steam generator. The heating device contains the heat exchanger. The invention also relates to a cooking appliance comprising at least one heat accumulator device of this type.

Description

The invention concerns a heat accumulator device and a cooking appliance comprising a heat accumulator device of this type.
Heat accumulator devices for cooking appliances are already known from the state of the art. Thus, for example, a recirculating oven for the cooking of food with hot air is known from DT 23 34 285 C3 in which a heat accumulator charged with an air stream is used to cover an initial heat requirement. The recirculating oven and the heat accumulator can be designed so that they are separate. As an example for this, a heat accumulator is shown, which is a closed aggregate with heating coils extending into the cooking chamber of the recirculating oven, these coils being filled, for example, with saline solutions that can be heated to a high temperature.
For the so-called Combi-steamers in which a cooking process with hot air and/or steam is possible, the use of energy storage and energy withdrawal systems is also already fundamentally known. Here one can refer, for example, to WO 99/63277 according to which, the energy stored in the energy storage and energy withdrawal system in the form of thermal, electrical and/or mechanical energy is usable in the cooking appliance, especially for at least partially operating a heating, a recirculating system, a humidity control, a steam generator and/or of a cooling device, using a measuring and controlling system. The described setup is quite complex.
The task of the present invention is to provide a heat accumulator device for a cooking appliance, which overcomes the disadvantages of the state of the art and, particularly, can be used in many different ways, especially in Combi-steamers, having low space requirement and high efficiency at the same time.
The task is solved according to the invention by a heat accumulator device for a cooking appliance with a housing that can be closed with a door, and which contains an interior section with a cooking chamber, at least one heating device for generating hot air and/or steam from a steam generator and a ventilator device for circulating hot air and/or steam in the cooking chamber, whereby the heat accumulator device comprises at least one accumulator container, which at least temporarily holds a medium that is liquid at least above a certain temperature, and at least one heat exchanger device, into which at least part of the medium can be pumped at least temporarily, and which extends into the interior section and into the steam generator, whereby the heating device contains the heat exchanger device.
Hereby a first insulation of the interior section and/or a second insulation of the heat accumulator container can be provided, whereby the first and/or second insulation preferably comprises a vacuum insulation.
Preferred embodiments of the invention are characterized by the fact that the heat exchanger device has at least three lines, whereby a first line extends from the accumulator container, preferably through at least one pump, into the interior section and/or into the steam generator, a second line extends from the interior section into the accumulator container and a third line extends from the steam generator into the accumulator container.
Hereby at least one first shutoff member in the first line, at least a second shutoff member in the second line and/or at least one third shutoff member in the third line can be provided, whereby preferably the first and second or the first and third or the second and third or the first, second and third shutoff members are integrated into one unit and/or can be switched together.
Furthermore, it is proposed with the invention that the heat exchanger device have two heat exchangers, one of which extends between the accumulator container and the interior section and the other extends between the accumulator container and the steam generator.
According to the invention it can also be provided that the heating device have a first heater in the interior section, which is preferably arranged concentrically to the fan wheel and ventilator device, a second heater for the steam generator, which is preferably arranged in the area of the water in the steam generator, and/or a third heater for the accumulator container, which is preferably arranged in the area of the accumulator medium.
Furthermore it is proposed that the heat exchanger device be arranged between the first and second line, concentrically to the fan wheel of the ventilation device, preferably between the fan wheel and the first heater.
According to the invention, it can be provided that the heat exchanger device be arranged between the first and third line in the water of the steam generator.
With the invention it is also proposed that the first, second and/or third heater be connected to a primary heater comprising at least one power source, at least one device for the combustion of auxiliary substances and/or at least one external heat transfer medium, whereby preferably the waste heat of the first, second and/or heater of the primary heater can be utilized at least partially.
Especially preferred practical examples of the invention are characterized by the fact that the accumulator container has at least two regions, whereby the regions can be connected to one another preferably through a fourth shutoff member, at least temporarily and at least in regions.
Hereby it can be provided that the third heater as well as the first, second and third lines be connected with a region of the accumulator container.
Furthermore, it is proposed with the invention, that a regulation and/or control device be used, which is in working connection with the heating device, preferably with the first, second and/or third heater, the ventilation device, the pump, the first shutoff member, the second shutoff member, the third shutoff member, the fourth shutoff member, at least one sensor unit, at least one input unit, at least one output unit, a modem and/or the internet.
According to the invention it can be provided that the medium be suitable for heat accumulation and/or during a phase change consume or liberate latent heat, whereby the medium comprises preferably a metal, a salt, a polymer, water, steam and/or superheated steam.
Furthermore, according to the invention it is proposed that heating of the medium, preferably through the third heater, can be loaded with energy in cooking phases during which little or no energy is needed, and/or in cooking pauses and/or via the waste heat, such as the heat of the waste air, condensate, noncondensed parts of a cooking medium, water of the steam generator, steam of the steam generator and/or excess steam.
The invention also concerns a cooking appliance with at least one heat exchanger device according to the invention.
Thus, the invention is based on the surprising finding that a heat exchanger device in the form of a compact heat exchanger can be used in the production of hot air and/or steam for a cooking appliance using at least one heat exchanger device, which extends from an accumulator container which is arranged separately from the interior section of the cooking appliance, both into the interior section of the cooking appliance as well as into the steam generator. Thus, a cooking appliance itself can be operated without the classical heating device in the cooking chamber and/or steam generator.
This construction opens up the possibility that both the accumulator container as well as the interior section can be provided with individual insulation. Preferably three lines are provided which enter the accumulator container, namely one to pump out accumulator medium from the accumulator container into the heat exchanger device, in the region of the interior section and/or of the steam generator, and two to return the accumulator medium from the interior section or from the heat generator to the accumulator container, which minimizes the loss of heat energy. The said lines can be designed to be thin, so that effective operation is possible.
According to the invention it was found to be especially advantageous to divide the accumulator container into two regions, which are separated from one another by a shutoff member, whereby in the first region a heating device is arranged, that extends into the region of the heat exchanger device, so that, as needed, either the complete accumulator medium in the accumulator container or only a part of it can be loaded with energy in the first region, and energy can be removed from it respectively.

Other characteristics and advantages of the invention follow from the description given below, in which two practical examples of it are described in detail, with the aid of a schematic drawing. The following are shown:

FIG. 1 shows a first cooking appliance according to the invention; and

FIG. 2 shows a second cooking appliance according to the invention.

As can be seen from FIG. 1, a cooking appliance 1 according to the invention comprises a housing 2 for limiting the interior section, which again comprises a cooking chamber 3 and a fan chamber 5 which is separated from the cooking chamber 3 by an air duct member 4. In the interior section a cooking medium 6 can be circulated by a fan wheel 7. The fan wheel 7 is driven by a motor 9 through axle 8. A heater 10 is arranged concentrically around the fan wheel 7 in the fan chamber 5. In addition, the interior section is insulated from the surroundings with the aid of insulation 11.
In order for cooking appliance 1 to be able to function as a Combi-steamer, in addition, a steam generator 20 is provided, which in turn comprises a heater 21 for heating water 22. In case of heating, the steam 23 rising from the water 22 arrives to the interior section through a line 24.
Separately from the interior section of the cooking appliance 1, a compact heat accumulator 30 is provided. This comprises an accumulator container 31, in which an accumulator medium 34 is arranged together with a heater 33 with insulation 32 in-between. The accumulator medium 34 may be solid at room temperature and melt only above room temperature when the heater 33 is operated, in order to be able to be pumped in a heat exchanger device 35, 36 through a line 37, 38. The heat exchanger device thereby comprises two regions, namely in the form of the heat exchanger 35, which extends into the steam generator 20, or better still within water 22, and in the form of the heat exchanger 36, which extends into the interior section, or better still into the fan chamber 6 between the fan wheel 7 and the heater 10.
Both the heat exchanger 35 as well as the heat exchanger 36 are connected to the accumulator container 31 through line 37, 38. More accurately stated, line 37 has a first line region 37 a, which extends from the accumulator medium 34 from the accumulator container 31 and then splits into two pumps 39, 40. Through the first pump 39, the accumulator medium 34 can be pumped into the heat exchanger 35 through line region 37 b in order to arrive back to accumulator container 31 through line region 37 c. Using the second pump 40, with intermediate switching of line region 38 b, the accumulator medium can arrive into heat exchanger 36 and through line region 38 c back into the accumulator container 31. Thus, the line region 37 a performs two functions, namely the aspiration of accumulator medium both for heat exchanger 35 as well as for heat exchanger 36, which is symbolized in FIG. 1 by using reference symbol 38 a.
One could also conceive that line regions 37 c, 38 c could meet, in order to enter together into the accumulator container 31 so that then the accumulator container 31 together with insulation 32 would only have to be broken through twice for the introduction of a line.
As can be seen in FIG. 1, the cooking appliance 1 according to the invention is constructed in a space-saving manner. Especially, the compact heat accumulator 30 does not cause an excessively large additional volume.
Besides that, the heat stored in the compact heat accumulator 30 can be transferred with low losses either to heat the recirculating cooking medium 6 or to produce steam 23 by the use of only three lines 37 a and 38 a respectively, 37 c and 38 c, which enter into the accumulator container 31. Hereby the insulations 11 and 32 ensure further reduction of heat loss.
The cooking appliance 1′ shown in FIG. 2 comprises essentially the same components as cooking appliance 1 of FIG. 1, so that the same parts can be identified with the same reference symbols, but with an apostrophe added. Actually, the cooking appliance 1′ according to the invention differs from cooking appliance 1 in three respects. As the first, it should be noted that in the embodiment of FIG. 2, the primary heaters 10 and 21 of cooking appliance 1 have been omitted, so that the heat exchangers 35′ and 36′ must assume the corresponding tasks of the embodiment of FIG. 2, which saves costs. The second obvious difference is that instead of the two pumps 39 and 40 of FIG. 1, now only one pump 41′ is used, in cooperation with two shutoff members 42′ and 43′ according to FIG. 2, which also saves cost. As a third difference, one can see that the accumulator container 31′ in FIG. 2 has two regions 31′a and 31′b which can be separated from one another through shutoff member 44′. The division of the accumulator container 31′ into two accumulator container regions 31′a and 31′b brings with it the advantage that optionally the amount of accumulator medium 34′ available can be adjusted, which permits fine setting of the amount of heat energy to be given off and taken up respectively.
During the operation of a cooking appliance 1, 1′ according to the invention, the complete cooking operation is set by means of a regulation and/or control device that is not shown, including the energy uptake and energy release of the accumulator medium 34, 34′. For this purpose, the regulation and/or control device is connected to motor 9, 9′, the heaters 10, 21 and 33, 33′, the pumps 39, 40 and 41′, as well as the shutoff members 42′, 43′ and 44′.
The accumulator medium 34, 34′ can be charged with energy through heaters 33, 33′, the water 22, 22′ and/or the cooking medium 6, 6′. A release of the energy of the accumulator medium 34, 34′ is possible simultaneously or in succession, both for the heating of the cooking medium 6, 6′ as well as of the water 22, 22′ to produce steam 23, 23′. Heat bridges between the accumulator container 31, 31′ with its insulation 32, 32′ to cooking appliance 1, 1′ itself, with its interior section set off by insulation 11,11′ and the steam generator 20, 20′, is optimized by using three thin lines 37 c, 37′c, 37 a, 38 a, 37′a, 38′a and 38 c, 38′c. Lines or channels through the accumulator container 31, 31′ are omitted according to the invention.
The characteristics disclosed in the above specification, in the claims as well as in the drawings can be essential both individually as well as in any arbitrary combination for the realization of the invention in its various embodiments.

REFERENCE SYMBOL LIST

1, 1′ Cooking appliance
2, 2′ Housing
3, 3′ Cooking chamber
4, 4′ Air duct member
5, 5′ Fan chamber
6, 6′ Cooking medium
7, 7′ Fan wheel
8, 8′ Axle
9, 9′ Motor
10 Heater
11, 11′ Insulation
20, 20′ Steam generator
21 Heater
22, 22′ Water
23, 23′ Steam
24, 24′ Line
30, 30′ Compact heat accumulator
31, 31′ Accumulator container
31′a, 31′b Accumulator container region
32, 32′ Insulation
33, 33′ Heater
34, 34′ Accumulator medium
35, 35′ Heat exchanger
36, 36′ Heat exchanger
37, 37′ Line
37 a, 37 b, 37 c, 37′a, 37′b, 37′c Line region
38,38′ Line
38 a, 38 b, 38 c, 38′a, 38′b, 38′c Line region
39 Pump
40 Pump
41′ Pump
42′ Shutoff member
43′ Shutoff member
44′ Shutoff member

Claims

1. Heat accumulator device for a cooking appliance with a housing that can be closed with a door which housing comprises an interior section with a cooking chamber, at least one heating device to produce at least one of hot air and/or or steam from a steam generator, and a ventilation device for circulating hot air and/or steam in the cooking chamber, wherein

the heat accumulator device comprises at least one accumulator container for at least temporary uptake of a medium which is fluid at least above a certain temperature, and at least one heat exchanger device into which at least one part of the medium can be pumped at least temporarily and which extends into the interior section as well as into the steam generator, wherein the heating device comprises the heat exchanger device.

2. Heat accumulator device according to claim 1, comprising at least one of a first insulation of the interior section and a second insulation of the accumulator container, whereby, wherein at least one of the first and second insulation comprises vacuum insulation.

3. Heat accumulator device according to claim 1, wherein the heat exchanger device comprises at least three lines, wherein a first line extends from the accumulator container into the interior section and/or into the steam generator, a second line extends from the interior section into the accumulator container and a third line extends from the steam generator into the accumulator container.

4. Heat accumulator device according to claim 3, comprising at least one first shutoff member in the first line, at least one second shutoff member in the second line and/or at least one third shutoff member in the third line, whereby at least the shutoff members are integrated into one unit and/or can be switched together.

5. Heat accumulator device according to claim 3, wherein

the heat exchanger device comprises two heat exchangers, one of which extends between the accumulator container and the interior section, and the other extends between the accumulator container and the steam generator.

6. Heat accumulator device according to claim 3, wherein

the heating device comprises a first heater in the interior section a second heater for the steam generator and/or a third heater for the accumulator container.

7. Heat accumulator device according to claim 3, wherein

the heat exchanger device runs between the first and second line concentrically to the fan wheel of the ventilation device.

8. Heat accumulator device according to claim 3, wherein

the heat exchanger device runs between the first and third line in the water of the steam generator.

9. Heat accumulator device according to claim 6, wherein at least one of

the first, second and third heater is in connection with at least a primary heater comprising at least one power source, at least one device for the combustion of auxiliary substances, and at least one external heat carrier.

10. Heat accumulator device according to claim 3, wherein

the accumulator container has at least two regions, whereby the regions can be connected to one another.

11. Heat accumulator device according to claim 10, wherein the third heater and the first, second and third lines are in connection with a region of the accumulator container.

12. Heat accumulator device according to claim 4, comprising

a regulation and/or control device which is in working connection with the heating device, the ventilation device, the pump, the first shutoff member, the second shutoff member, the third shutoff member, at least one sensor unit, at least one input unit, at least one output unit, and a modem or the internet.

13. Heat accumulator device according to claim 1, wherein

the medium is suitable for heat accumulation and/or it utilizes or liberates latent heat during a phase transformation.

14. Heat accumulator device according to claim 1, wherein

the heating of the medium is loaded with energy in the cooking phases in which little or no energy is needed and/or during cooking pauses and/or through waste heat.

15. Cooking appliance with at least one heat accumulator device according to claim 1.

16. Heat accumulator device according to claim 3, wherein the first line extends through at least one pump into at least one of the interior section and/or the steam generator.

17. Heat accumulator device according to claim 4, wherein the first and second shutoff members, or the first and third shutoff members, or the second and third shutoff members, or the first, second, and third shutoff members are integrated into one unit and/or can be switched together.

18. Heat accumulator device according to claim 6, wherein the first heater is arranged concentrically around the fan wheel of the ventilation device.

19. Heat accumulator device according to claim 6, comprising a second heater for the steam generator arranged in the region of the water in the steam generator.

20. Heat accumulator device according to claim 6, comprising a third heater for the accumulator container arranged in the region of the accumulator medium.

21. Heat accumulator device according to claim 7, wherein the heat exchanger device runs between the fan wheel and the first heater.

22. Heat accumulator device according to claim 9, wherein the waste heat of at least one of the first, second, and third heaters is used at least partially by the primary heater.

23. Heat accumulator device according to claim 10, wherein the regions of the accumulator container are connected to one another through a fourth shutoff member, at least temporarily, at least in some regions.

24. Heat accumulator device according to claim 12, wherein the regulation and/or control device is in working connection with at least one of the first, second, and third heaters

25. Heat accumulator device according to claim 13, wherein the medium comprises at least one of a metal, a salt, a polymer, water, steam, and superheated steam.

26. Heat accumulator device according to claim 14, wherein the third heater is loaded with energy in the cooking phases in which little or no energy is needed and/or during cooking pauses and/or through waste heat.

27. Heat accumulator device according to claim 14, wherein the waste heat comprises the heat of at least one of waste air, condensate, non-condensed parts of a cooking medium, water of the steam generator, steam of the steam generator, and superheated steam.