DE102022106372A1 - Cooking appliance with inflow channel and return flow channel for a hot gas stream - Google Patents

Abstract

The invention relates to a cooking appliance (1) with at least one cooking chamber (2), a heating device (4), a fan (5), an inflow channel (7) which has a flow (8) of a hot gas stream (6) from the heating device (4) to the Cooking chamber (2), and a return flow channel (10), which directs a return (11) of the hot gas stream (6) from the cooking chamber (2) to the heating device (4), one of the two channels (7, 10) having an evaporator (16) is connected, which flows through or around which the flow (8) or the return (11) of the hot gas stream (6) flows. The object of the invention is to provide a cooking appliance in which a flow path of the hot gas stream for heating the cooking space and of the evaporator can be actively and flexibly controlled. This object is achieved in that a lockable bypass device (16) is provided which, in the open position, directs the hot gas stream (6) from the inflow channel (7) directly to the return flow channel (10).

Description

The invention relates to a cooking appliance with at least one cooking chamber, a heating device, a fan, an inflow channel which directs a flow of a hot gas stream from the heating device to the cooking chamber, and a return flow channel which directs a return flow of the hot gas stream from the cooking chamber to the heating device, wherein one of the two channels is connected to an evaporator through which the flow or return of the hot gas stream flows or flows around.

A cooking appliance can be, for example, an oven, a steamer or a combination steamer. If the cooking appliance is designed as an oven, the cooking space is also referred to as a baking space or oven.

A cooking appliance designed as an oven, in particular a deck oven, with the above-mentioned features is known, for example, from the patent registered by the applicant DE 195 16 514 C2 . The deck oven has a plurality of baking ovens arranged one above the other to accommodate baking trays filled with baked goods. The baking trays are inserted and removed via the oven doors assigned to the baking stoves. A heating device designed as a burner device with a heat exchanger and a fan are used in the in DE 195 16 514 C2 disclosed deck oven to generate a hot gas stream with which the oven atmosphere is indirectly heated. For indirect heating, the hot gas stream flows via an inflow channel known as a distribution channel arrangement into individual heating radiators assigned to the baking ovens, via which the heat of the hot gas stream is transferred to the individual baking ovens. Due to a closed flow circuit, the hot gas stream is not mixed with the furnace atmosphere. The heating radiators have heating current supply channels combined in pairs, with each heating current supply channel being assigned a heating current return channel on the side. The flow of the hot gas flow is led to the baking ovens through the heating current supply channels and the return flow of the hot gas flow is directed away from the baking ovens through the heating current return channel. This allows a uniform volume flow to be achieved over the surface of the heating radiator. The return of the hot gas stream cooled in the heating radiators to the burner device continues through a return flow channel known as a collecting channel. The flow path for the hot gas stream is predetermined as a whole and cannot be changed.

The baking stoves of the in DE 195 16 514 C2 The disclosed deck oven also has a steam supply device on the rear wall, which is connected to an evaporator via a steam supply line. Details about the evaporator are not disclosed. In general, an evaporator produces water vapor, which is also known in technical jargon as steam clouds or plumes. The effect of the steam on the food cooked in the cooking appliance positively influences the cooking result of the food. To generate the steam plume, the evaporator is heated and water is added to or on the evaporator. If the cooking appliance is an oven, the evaporator can be heated, for example, by the flow or return of the hot gas stream.

If, in cooking appliances with the above features, the evaporator is heated by means of the hot gas stream to heat the cooking space, a steam cloud can only be generated if the cooking space is also to be heated. Short cooking times are often not enough to heat the evaporator to the temperature required to generate steam. In this case, preheating of the evaporator is necessary, but this can have a detrimental effect on the cooking process since the cooking space is also undesirably preheated. The undesirable preheating of the cooking space can affect the cooking result and/or a lot of energy is used unnecessarily.

The object of the invention is therefore to provide a cooking appliance in which a flow path of the hot gas stream for heating the cooking space and the evaporator can be actively and flexibly controlled. Such a cooking device achieves a high level of flexibility as well as a high level of time and energy efficiency while achieving high-quality cooking results.

This task is solved by a cooking appliance with all of the features of patent claim 1.

The cooking appliance has at least one cooking chamber, a heating device, a fan, an inflow channel, which directs a flow of a hot gas stream from the heating device to the cooking chamber, and a return flow channel, which directs a return flow of the hot gas stream from the cooking chamber to the heating device. One of the two channels, i.e. the inflow channel or the return flow channel, is connected to an evaporator through which the flow or return of the hot gas stream flows or is flowed around.

The heating device and the fan generate the hot gas stream, which regularly flows from the heating device through the fan and is conveyed as a feed through the inflow channel. The inflow channel opens into or leads to the cooking space This means that the oven atmosphere in the cooking chamber is heated, for example as described above in connection with the prior art. From the cooking space or from the inflow channel, the hot gas stream flows downstream of the cooking space as a return flow through the return flow channel back to the heating device and/or at least partially to a chimney.

The evaporator can in particular be a device with a heat storage element made of a material with high heat storage capacity, for example metal, in particular cast metal. At least a section of the inflow channel or the return flow channel leads to the evaporator. Because the flow or return flows through or around the evaporator, the heat storage element is heated and the water directed onto the surface of the heat storage element evaporates. The steam formed is led into the cooking chamber. Alternatively, it is also possible to design at least a section of the inflow channel or the return flow channel with a large cross section, so that the evaporator can be arranged in this section and the flow or return can flow around it. This also makes it possible to transport the water that evaporates when it hits the surface of the heat storage elements into the cooking space as steam clouds.

To solve the above problem, the cooking appliance has a lockable bypass device which, in the open position, directs the hot gas stream from the inflow channel directly to the return flow channel.

In other words, the inflow channel and the return flow channel are connected by means of a fluid-conducting connection and the connection can be closed or opened. When the connection is open, the bypass device is in the open position. Then at least part of the flow that flows completely from the heating device to the cooking space when the connection is closed can be branched off and directed directly into the return flow channel without first flowing to the cooking space. The connection is closed by a closing device, in particular by covering an opening forming the connection with a cover. This cover is designed to be actively adjustable, that is, a position or position of the cover can be changed by an actuator. When the connection opening is closed by means of the cover, the bypass device is in the closed position and the flow cannot flow directly from the inflow channel into the return flow channel. Further details about the coverage are described below.

By means of the closable bypass device connecting the inflow channel and the return flow channel, the hot gas stream can be flexibly routed in accordance with predetermined heat requirements of the cooking appliance. In particular, such flexible routing of the hot gas stream makes it possible to heat individual areas of the cooking appliance according to individual requirements and even independently of each other with the hot gas stream. For example, it is possible to heat the evaporator more quickly or even to heat it selectively independently of the cooking space if the connection between the inflow channel and the return flow channel is open. In addition, it is also possible to individually heat other areas that are connected to the flow channel, or even other devices connected to the cooking device, with the hot gas stream. If, for example, a fermentation chamber or a warming chamber are connected to the inflow channel or the return flow channel of the cooking appliance, these can also be heated with the hot gas stream according to individual requirements when the bypass device is at least partially open. Overall, the flexibility of such a cooking device is significantly increased.

Additionally or alternatively, energy can be saved during a cooking process by independently heating the evaporator. Because if it is not necessary to actively heat the cooking space in certain cooking phases, the thermal energy of the hot gas stream can be supplied to the evaporator in a targeted manner, so that the cooking process with the cooking appliance described here is compared to a cooking process with a cooking appliance known from the prior art overall energy can be saved. By targeted heating, the evaporator can also be brought to the temperature required to generate steam more quickly, so that the overall cooking process can be shortened. These advantages are achieved with the cooking appliance described here in a structurally simple manner, so that the cooking appliance and the cooking process carried out with it are cost-efficient and an excellent cooking result can be achieved.

In practice, the cooking appliance can be an oven, in particular a deck oven. If the cooking appliance is designed as an oven, it is particularly advantageous to heat the evaporator with the hot gas stream, which is also used to heat the baking chamber. This is because the temperature of the hot gas stream in an oven is regularly particularly high and this heat cannot regularly be fully utilized to heat the cooking chamber designed as a baking chamber. Excess heat can then be used conveniently to heat the evaporator.

A baking process often only takes a short time due to the high temperature of the hot gas stream. In the ovens known from the prior art with the features described above, a short time is usually not enough to generate a steam cloud as desired, which is often needed suddenly and in large volumes during baking, because the evaporator is not heated up sufficiently during the short baking time. It therefore makes sense, particularly in ovens, to be able to heat and, in particular, preheat the evaporator independently of the baking chamber. Of course, selective preheating of the evaporator can also be useful for longer baking times.

In a first embodiment, the oven can be a deck oven in which the oven atmosphere is heated, for example, as is known from the prior art, by passing flue gases as a hot gas stream through heating radiators, which form the wall of the baking chamber and heat the baking chamber. This embodiment is referred to as a heating gas circulation furnace in DIN 8766. The baking chamber is then not fluidly connected to the channels mentioned for the hot gas (flue gas). For the purpose of indirectly heating the furnace atmosphere, multi-deck furnaces have a closed channel arrangement with an inflow channel and a return flow channel, into which the bypass device can be integrated with very little design effort. The heating device in this case is a burner device and the flue gases from the burner form the hot gas stream that flows through the heating radiators and the steam apparatus.

Alternatively, the cooking appliance can be a convection oven, in particular a rack oven, with hot gas flowing through the cooking space and being fluidly connected to the channels mentioned. This embodiment is referred to as a hot air circulation oven in DIN 8766. In a cooking appliance whose cooking chamber and channel guide are fluidly connected to one another, the hot gas stream for heating the cooking chamber and the steam apparatus is the heated cooking chamber atmosphere. This hot gas stream can be heated, for example, via a heat exchanger within the furnace housing.

In practice, the evaporator can be arranged in or on the return flow channel. In other words, the return flow in particular can flow through the evaporator or flow past it and heat the evaporator. If the evaporator is arranged in or on the return flow channel, the power of the heating device required to properly heat the baking chamber and the evaporator is particularly low. In particular, it is lower than the power required to heat the baking chamber and an evaporator arranged in or on the inflow channel. If the heating device is arranged in the return flow channel and the heating device is designed as a burner device, the energy saving can be 10 to 15% compared to the arrangement of the evaporator in the inflow channel.

In practice, the inflow channel and the return flow channel can have a common partition and the bypass device can be a closable opening arranged in this partition. It is sufficient if only a limited section of the inflow channel and the return flow channel are separated by a common partition. If the opening in the partition is not closed, the inflow channel and the return channel are directly connected to each other.

The closing device already described above for closing the opening can in practice be a flap that can be moved by means of the actuator. This flap is suitable for covering or releasing the opening in the common partition between the inflow channel and the return flow channel. For this purpose, when the bypass device is in the closed position, the first side of the flap lies against the partition wall and thus covers the opening. The flap can be pivoted into the inflow channel using the actuator around a joint attached to the partition wall. In the open position, the flap rests against the partition wall with a second side, which is opposite the first side, or it protrudes into the inflow channel so that it blocks its cross section. Such a design of the cover is structurally particularly simple and functionally reliable because only simple components are used. Alternatively, the closing device can also be a slider which, depending on its position, completely or partially covers the opening. The closing device can also be a slatted shutter in the manner of blinds, or a central shutter in the manner of aperture diaphragms. An actuator with a shorter travel distance can be used for this. The actuator can be, for example, an electrically, hydraulically or pneumatically driven actuator.

• - der Strömungsweg vom Zustromkanal in den Garraum ist geöffnet und die Öffnung zwischen dem Zustromkanal und dem Rückstromkanal ist geschlossen;
• - der Strömungsweg vom Zustromkanal in den Garraum ist geschlossen und die Öffnung zwischen dem Zustromkanal und dem Rückstromkanal ist geöffnet;
• - der Strömungsweg von Zustromkanal in den Garraum ist teilweise geöffnet und die Öffnung zwischen dem Zustromkanal und dem Rückstromkanal ist teilweise geöffnet.

In practice, the flap can be a flap that can assume the following three positions:

• - the flow path from the inflow channel into the cooking space is open and the opening between the inflow channel and the return flow channel is closed;
• - the flow path from the inflow channel into the cooking space is closed and the opening between the inflow channel and the return flow channel is open;
• - The flow path from the inflow channel into the cooking space is partially open and the opening between the inflow channel and the return flow channel is partially open.

For these positions, the geometry of the flap is selected such that the cross section of the inflow channel downstream of the opening is essentially completely blocked when the bypass device is open and the flap protrudes into the inflow channel oriented transversely to the flow direction. This means that the hot gas flow can be controlled particularly precisely and cooking with the cooking appliance is particularly efficient. In particular, it is also possible to switch between the above positions during a cooking process in accordance with the heat requirements of the cooking space or the evaporator - even for only short periods of time.

In practice, the partition wall between the inflow channel and the return flow channel can be arranged above the cooking space. The return flow channel is then arranged, for example, above the inflow channel, which in turn is arranged above the cooking space. This arrangement means that the cooking appliance takes up particularly little floor space. In addition, optimal heat distribution in the inflow channel, the cooking space and the return flow channel is guaranteed, because radiant heat that the cooking space loses to the environment is at least partially transported back into the cooking space with the inflow.

• 1 das erfindungsgemäße Gargerät, ausgebildet als ein Etagenbackofen, in einer Seitenansicht mit teilweise geschnittener Seitenwand und mit geschlossener Abdeckung der Bypass-Vorrichtung;
• 2a eine Detailansicht des in 1 mit II bezeichneten Bereichs des erfindungsgemäßen Gargeräts mit geschlossener Abdeckung der Bypass-Vorrichtung; und
• 2b eine Detailansicht des in 1 mit II bezeichneten Bereichs des erfindungsgemäßen Gargeräts mit geöffneter Abdeckung der Bypass-Vorrichtung.

Further practical embodiments and advantages of the invention are described below in connection with the drawings. Show it:

• 1 the cooking appliance according to the invention, designed as a deck oven, in a side view with a partially cut side wall and with the cover of the bypass device closed;
• 2a a detailed view of the in 1 Area designated II of the cooking appliance according to the invention with the cover of the bypass device closed; and
• 2 B a detailed view of the in 1 Area of the cooking appliance according to the invention designated II with the cover of the bypass device open.

1 shows a partially sectioned side view of a cooking device 1 designed as a deck oven, with a total of six cooking rooms arranged one above the other and designed as baking rooms 2, which are also referred to as stoves. The baking chambers 2 are separated from one another in the vertical direction by heating radiators 3. Alternatively, the cooking appliance 1 can also be, for example, a steamer or a combination cooker.

Above the top baking chamber 2 there is a heating device 4 for heating a hot gas stream 6 generated by a fan 5. The heating device 4 can, for example, be a burner device 4, with the flue gases produced during combustion forming the hot gas stream 6. The hot gas stream 6 flows in an inflow channel 7 from the blower 5 to the individual heating radiators 3, the hot gas stream 6 flowing in the inflow channel 7 being referred to as the flow 8. Like the heating device 4, at least a first section of the inflow channel 7 is arranged above the uppermost baking chamber 2; a second section of the inflow channel 7 is arranged on the back of the baking rooms 2, which is opposite the baking room doors 9 of the baking rooms 2. The baking chambers 2 are heated indirectly by transferring the heat stored in the hot gas stream 6 from the heating radiators 3 to the atmosphere in the baking chambers 2.

When the hot gas stream 6 cooled in the heating radiators 3 has left the heating radiators 3, the hot gas stream 6 is led back through a return flow channel 10 to the heater 4 and the blower 5. The hot gas stream 6 flowing in the return flow channel 10 is referred to as return 11. For the return of the return 11, a first section of the return flow channel 10 is arranged on the back of the baking chambers 2 behind the second section of the inflow channel 7 and a second section of the return flow channel 10 above the first section of the inflow channel 7.

Due to this arrangement of the return flow channel 10 adjacent to the inflow channel 7, the inflow channel 7 and the return flow channel have a common partition 12. This reduces heat losses from the inflow channel 7 because the return flow channel 10 is arranged on its sides facing away from the baking chambers, in which the return 11 flows at a temperature well above the ambient temperature.

The flow 8 and the return 11 of the hot gas stream 6 form a closed circuit in the cooking appliance described here.

In an alternative embodiment of the cooking appliance, not shown here, for example a convection oven, it is also possible to heat the cooking space directly with the hot gas stream by the flow flowing into the cooking space and the return flowing from the cooking space to a fan. In this embodiment, the hot gas stream is the cooking chamber atmosphere, which flows past the steam apparatus and in the sense of Invention is guided through the inflow channel and the return flow channel.

In the 1 The individual baking rooms 2 shown have baking room doors 9 on a front side 13 of the deck oven 1 for closing loading openings. On their rear wall 14, the individual baking chambers 2 are each connected to a steam supply line 15 so that they can flow through, the steam supply lines 15 in turn being connected to an evaporator 16, which is also referred to as a steam apparatus. Via the steam supply lines 15, it is possible to convey a vapor swath from the evaporator 16 into the individual baking rooms 2.

The steam apparatus or evaporator 16 is connected to a supply line for water (not shown) and is designed so that it can evaporate large amounts of water and supply it to the baking chambers 2. The evaporator 16 is arranged in the return flow channel 10 and is heated by the return 11 of the hot gas stream 6. Alternatively, the steam apparatus 16 can also be arranged in the inflow channel 7 (not shown). Heat storage elements (not shown), usually rods or similar elements made of steel, can be arranged in the steam apparatus 16.

The deck oven 1 also has a lockable bypass device 17 which, in the open position, directs the hot gas stream 6 from the inflow channel 7 directly to the return flow channel 11. The bypass device 17 is in 1 in the area marked II and enlarged in the 2a and the 2 B shown. They show 1 and the 2a the bypass device 17 in a first, closed position and the 2 B shows the bypass device 17 in a second, open position.

The 2a and the 2 B It can be seen that the bypass device 17 has an opening 18 formed in the partition 12 between the inflow channel 7 and the return flow channel 10. The opening 18 can be closed by means of a closing device designed as a flap 19. For this purpose, the flap 19 is designed as a substantially flat sheet metal, the area of which is larger than the opening 18, so that the flap 19 can be placed against the partition wall 12 with a first side covering the opening 18. When the opening 18 is covered by the flap 19, the bypass device 17 is in the in 1 and 2a first, closed position shown. In this closed position of the bypass device 17, the flow path of the hot gas stream 6 from the inflow channel 7 into the cooking chambers 2 is open.

In contrast to the closed position, the bypass device 17 is in the in 2 B shown second, open position, when the opening 18 is released by the flap 19 and the flow path of the hot gas stream 6 from the inflow channel 7 into the cooking chambers 2 is blocked by means of the flap 19. So that the flap 19 can essentially completely block the flow cross section that leads from the inflow channel 7 into the cooking chambers 2, the size of the flap 19 corresponds at least to the size of a cross section 22 of the inflow channel 7 adjacent to the opening 18 downstream.

In the open position, the inflow channel 7 and the return flow channel 10 are connected to one another so that flow can flow through them directly, so that at least part of the flow 8 flowing completely from the heating device 4 to the baking chambers 2 when the opening 18 is closed can be branched off and directed directly into the return flow channel 10, without first flowing to the baking rooms 2.

The opening or closing of the opening 18 is carried out by pivoting the flap 19 about a joint 20 fixed to the partition 12 by means of an actuator 21 also attached to the partition 12. The actuator 21 is usually an electric drive, but can also be pneumatic or be hydraulically operated and have a control that is connected to the oven control. By connecting the actuator control to the oven control, the actuator position and thus the position of the flap can be adjusted during a baking process.

The bypass device 17 can also be brought into any partially open intermediate position (not shown). In the intermediate position, the flap 19 is in a position between the first and second positions. The opening 18 is then not completely closed by the flap 19 and the flap 19 projects into the inflow channel 7 without completely closing it. In other words, both the flow path from the inflow channel 7 into the baking chambers 2 is partially open and the opening 18 between the inflow channel 7 and the return flow channel 10 is partially open.

With the based on the 1 , 2a and 2 B With the arrangement described, it is possible to move the flap 19 flexibly into one of the positions described above during a baking process, so that the hot gas stream 6 can be flexibly directed in accordance with predetermined heat requirements of the baking chambers 2 or the evaporator 16.

This flexibility significantly improves the performance of the cooking appliance described here. In conventional cooking appliances without a bypass device, the evaporator is only heated when the burner device and the fan are operated. By switching off the burner device, the heat supply to the evaporator is also interrupted.

Due to the bypass device 17, it is possible with the arrangement described here to heat the evaporator 16 independently of the baking chambers 2. With the bypass device 17 open (cf. 2 B) the hot gas stream 6 flows directly from the burner device 4 through the opening 18 in the partition 12 into the upper, second section of the return flow channel 10, in which the evaporator 16 is located. Consequently, the entire heating energy of the burner device 4 is supplied to the evaporator 16. This can be useful, for example, before loading the oven if no heating energy is to be supplied to the baking chambers 2, but the evaporator 16 needs to be heated up to operating temperature.

Phases can also occur during the baking operation in which the baking chambers 2 require no energy supply or only a small energy supply, but the steam apparatus/evaporator 16 must be heated intensively. This can be the case immediately after the evaporator 16 releases a burst of steam. The bypass device 17 can also be opened during this period ( 2 B) , so that the hot gas stream 6 flows directly from the burner device 4 through the opening 18 in the partition 12 to the evaporator 16.

If, on the other hand, the baking rooms 2 have an increased energy requirement, the bypass device 17 can be closed (cf. 2a) , so that the hot gas stream 6 flows from the burner device 4 through the baking chambers 2 and only then past the steam apparatus/evaporator 16.

Furthermore, the heating energy of the burner can be divided as desired by moving the flap 19 into an intermediate position, so that a first predetermined portion of the hot gas stream 6 flows into the baking chambers 2 and the remaining portion of the hot gas stream 6 flows directly through the opening 18 in the partition 12 Evaporator 16.

The features of the invention disclosed in the present description, in the drawings and in the claims can be essential for the implementation of the invention in its various embodiments, both individually and in any combination. The invention is not limited to the embodiments described. It can be varied within the scope of the requirements and taking into account the knowledge of the responsible specialist.

Reference symbol list

1

Cooking appliance, deck oven

2

Cooking room, baking room

3

Heating radiators

4

Heating device, burner device

5

fan

6

Hot gas flow

7

Inflow channel

8th

leader

9

Baking room doors

10

Return flow channel

11

Rewind

12

partition wall

13

Front

14

Back wall

15

Steam supply lines

16

Evaporator, steam apparatus

17

Bypass device

18

opening

19

Locking device, flap

20

joint

21

Actor

22

Cross section of the inflow channel

QUOTES INCLUDED IN THE DESCRIPTION

This list of documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 19516514 C2 [0003, 0004]

Claims (7)

Cooking appliance (1) with at least one cooking chamber (2), a heating device (4), a fan (5), an inflow channel (7) which has a flow (8) of a hot gas stream (6) from the heating device (4) to the cooking chamber (2 ), and a return flow channel (10), which directs a return flow (11) of the hot gas stream (6) from the cooking chamber (2) to the heating device (4), one of the two channels (7, 10) having an evaporator (16) is connected, which flows through or is flowed around by the flow (8) or the return (11) of the hot gas stream (6), characterized by a lockable bypass device (17) which, in the open position, removes the hot gas stream (6) from the inflow channel (7 ) leads directly to the return flow channel (10). cooking appliance Claim 1 , characterized in that the cooking appliance (1) is an oven (1), in particular a deck oven (1). cooking appliance Claim 1 or 2 , characterized in that the evaporator (16) is arranged in or on the return flow channel (10). Cooking device according to one of the Claims 1 until 3 , characterized in that the inflow channel (7) and the return flow channel (10) have a common partition (12) and that the bypass device (17) is a closable opening (18) arranged in this partition (12). cooking appliance Claim 4 , characterized in that the opening (18) can be closed by a flap (19) movable by means of an actuator (21). cooking appliance Claim 5 , characterized in that the movable flap (19) is a flap (19) which can assume the following three positions: - Flow path from the inflow channel (7) into the cooking space (2) is open and the opening (18) between the inflow channel (7) and the return flow channel (10) is closed; - Flow path from the inflow channel (7) into the cooking space (2) is closed and the opening (18) between the inflow channel (7) and the return flow channel (10) is open; - Flow path from the inflow channel (7) into the cooking space (2) is partially open and the opening (18) between the inflow channel (7) and the return flow channel (10) is partially open. cooking appliance Claim 4 , characterized in that the partition (12) is arranged between the inflow channel (7) and the return flow channel (10) above the cooking space (2).

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