oven

Abstract

oven (1) with - a baking chamber (6), - a heating device (14), - a blower (9) for conveying air located in the baking chamber (6), - a chimney (13) through which the air from the baking chamber (6) can flow into the surroundings, and - a fresh air opening (31) through which air from the environment can flow into the baking chamber (6), characterized in that the oven (1) has an air duct (7) in which the impeller of the blower (9) is arranged, wherein the air duct (7) downstream of the blower (9) has a plurality of flow paths (19, 20), of which a first flow path (19) leads to the chimney (13) and a second flow path (20) leads back into the baking chamber (6), and wherein a pivotable guide flap (11) is arranged in the air duct (7) which selectively directs the air from the blower (9) into at least one of the flow paths (19, 20).

Description

[0001] The invention relates to an oven with a baking chamber, a heating device, a fan for conveying air in the baking chamber, a chimney through which the air from the baking chamber can flow out into an environment, and a fresh air opening through which air from the environment can flow into the baking chamber.

[0002] Such an oven, in particular a rack oven, is known, for example, from document DE 199 20 583 A1. The oven has a heat exchanger arranged above the baking chamber as a heating device for heating air.

[0003] In the oven, a fan extracts the air from the baking chamber and transports it to the heat exchanger. The baking chamber is therefore located on the suction side of the fan, and the heat exchanger on the pressure side. The air heated by the heat exchanger is conveyed downstream from the heat exchanger into the baking chamber. From there, the air is sucked in again by the fan, forming a flow circuit. Through the convective movement of the air, the heat from the heat exchanger is transported into the baking chamber and transferred to the baked goods inside, allowing the baked goods to be baked. The oven described thus has a non-static baking atmosphere, like rack ovens in general. Together with the heat exchanger, the fan and the resulting air circulation serve as the primary heating.

[0004] During a baking process, it is regularly necessary for air to escape from the baking chamber, at least for a limited period of time. This is necessary, for example, if moisture escapes from the baked goods in the baking chamber during baking (so-called inherent vapors). If the air in the oven is merely circulated as described above, the escaping moisture can cause undesirable changes to the composition of the oven atmosphere. Excessive humidity, for example, can negatively influence the crust formation of the baked goods baked in the baking chamber.

[0005] In order to be able to regulate the humidity in the oven atmosphere, the oven disclosed in document DE 199 20 583 A1 has a guide device for controlling the air flow.

[0006] This air flow control device comprises a coverable first duct, a coverable second duct, and a combination flap assembly. The first duct is located on the pressure side of the fan on the heat exchanger and is connected to a chimney so that air can flow out of the baking chamber into the environment. The second duct leads from a fresh air opening into the baking chamber. Fresh air from the environment can flow into the baking chamber through this. The first and second ducts are arranged adjacent to one another and can be covered by the combination flap assembly, which comprises two plates and a shaft. A first plate can cover the first duct and a second plate can cover the second duct. The two plates can be actively raised and lowered together using the shaft, so that the two ducts can be actively exposed and covered.

[0007] During a baking process, the two plates are regularly in the covering position. In this covering position, the second plate can be locked, but the first plate cannot. If the baking chamber is humidified, the unlocked first plate can be passively raised by any resulting excess pressure, while the second plate remains locked. The excess pressure can then escape via the chimney. If the oven atmosphere needs to be replaced with fresh air, for example if the oven atmosphere has a high level of humidity (so-called steam removal), the two plates can be actively raised via the shaft. Fresh air then flows into the baking chamber via the fresh air opening, i.e. the second duct, and air in the baking chamber flows out into the environment via the first duct.

[0008] Setting different flow paths is limitedly flexible with the oven known from the prior art with a fan and a guide device for controlling the air flow in the oven, in particular for controlling the steam removal.

[0009] The document DE 102 45 773 C1 describes a cooking appliance with a housing and a heatable cooking chamber with an air intake opening and a valve within the housing. A valve is provided to control the supply and exhaust air of the cooking chamber. In a bypass position, it connects the cooking chamber exhaust opening with the cooking chamber supply air opening and the appliance supply air opening with the appliance exhaust air opening. In the bypass position, only the cooking chamber atmosphere is circulated in recirculation mode. The valve can also be switched to through-air mode, in which supply air is fed from the appliance supply air opening into the cooking chamber and exhaust air is discharged via the cooking chamber exhaust air opening to the appliance exhaust air opening. This design is complex.

[0010] The object of the invention is therefore to provide an oven in which the air flow in the oven can be actively and flexibly controlled, with the air flow control device being implemented cost-effectively and with a simple technical design. Overall, such an oven achieves energy savings while achieving high-quality baking results.

[0011] The object is achieved according to the invention in that the baking oven has an air duct in which the impeller of the fan is arranged, wherein the air duct downstream of the fan has a plurality of flow paths, of which a first flow path leads to the chimney and a second flow path leads back into the baking chamber, and in that a pivotable guide flap is arranged in the air duct, which selectively guides the air from the fan into at least one of the flow paths.

[0012] The fan can, for example, be arranged in the oven such that an inlet located on the intake side of the fan is connected to the baking chamber in a flow-through manner. The fan can thus, for example, draw air from the baking chamber when it is in operation. The air duct can, for example, be arranged on the pressure side of the fan, so that air is conveyed from the baking chamber via the fan into the air duct when the fan is in operation. Of course, it is also possible to arrange the fan in the air duct itself.

[0013] The air duct can be a substantially closed structure with a main duct, a plurality of secondary ducts, an inlet opening arranged on the main duct, and a plurality of outlets on the secondary ducts pointing in the direction of flow. The plurality of secondary ducts then branch off from the main duct, so that the plurality of secondary ducts form the plurality of flow paths of the air duct. In particular, the air duct with the secondary ducts can be designed as a sheet metal structure on the rear wall of the oven.

[0014] The air duct can be connected to the baking chamber via a connecting duct, which is arranged, for example, between the baking chamber and the rear wall of the oven. The connecting duct leads, for example, from the rear wall of the baking chamber downstream to the inlet opening of the main duct of the air duct. The fan, for example, can then be arranged in the main duct. The impeller of the fan can draw air from the baking chamber through the inlet opening via the connecting duct. The air then flows radially from the impeller of the fan into the main duct. Downstream of the fan, the main duct can be divided into a plurality of flow paths, i.e., a plurality of secondary ducts, wherein each secondary duct can have its own outlet, for example, to a chimney or back to the baking chamber. For example, the air duct can be designed in the form of a Y-shaped fork.The lower section of the Y-shaped fork can then, for example, represent the main duct, and the two upper sections of the Y-shaped fork can represent the plurality of secondary ducts. Of course, the air duct can also have any shape other than a Y that is suitable for the invention.

[0015] In the oven according to the invention, the air duct is designed such that a first flow path, for example, a first secondary duct, leads to the chimney, and a second flow path, for example, a second secondary duct, leads back into the oven. Additionally, the air duct can have one or more additional flow paths, for example, a third and / or a fourth flow path (secondary duct), so that, for example, multiple flow paths can lead back into the oven to ensure uniform airflow through all areas of the oven.

[0016] An adjustable guide device, namely a pivoting guide flap, is arranged in the air duct, which selectively directs the air blown by the fan into at least one of the flow paths. This means that the air flowing through the main channel of the air duct can be directed by the guide device either into the first flow path (e.g., the first secondary channel) of the air duct or into the second flow path (e.g., the second secondary channel). If additional flow paths are provided, these can also be selectively switched on or off via the guide device.

[0017] When the air is directed from the adjustable guide device via a flow path into the chimney, fresh air from the ambient air can flow into the baking chamber via the fresh air opening. To allow fresh air to flow from the ambient air into the baking chamber via the fresh air opening, the fresh air opening can be decoupled from the air duct, i.e., it can be located at a different point in the oven than the air duct, for example. In the simplest case, the fresh air opening can be a simple opening in any wall of the baking chamber. In particular, the fresh air opening can be an opening that is made in the top of the baking chamber and extends through a top wall of the oven. However, the fresh air opening can also be controllable, i.e., opened and closed, via a separate closing device. For example, the closing device can be a flap or a one-way valve.The flap and / or the one-way valve can be held closed, for example, by a spring or by its own weight, and can open passively, for example, so that pressure equalization occurs in the oven chamber when air in the oven flows out through the chimney, creating a negative pressure. Further embodiments of a separate closure device are described below.

[0018] The guide device arranged in the air duct is adjustable, i.e., the position of the guide device can be changed manually or with an actuator. The adjustable guide device allows the air from the main duct to be selectively directed to at least one of the flow paths. For example, in a first position of the guide device, the air flow can be directed into the first flow path of the air duct. In a second position of the guide device, the air flow can be directed, for example, into the second flow path. In a third position of the guide device, the air flow can, for example, be directed partially into the first flow path and partially into the second flow path. Further details on the design of the adjustable guide device are described below.

[0019] The described oven allows the air flow within the oven to be advantageously influenced. In particular, the air duct and the adjustable guide device are of particularly simple construction, so that the probability of oven failure is low and, in the event of a defect, repair is easy. Thanks to the air duct and the adjustable guide device, a single fan can also be sufficient to circulate the air in the oven and de-steam the baking chamber. Another advantage is that the fresh air opening and the air duct are decoupled from one another. This allows the air in the oven to be circulated without any air entering or exiting the oven, and the temperature of the oven atmosphere remains essentially constant. As a result, energy can be saved during a baking process.It is also advantageous that the described oven enables the partial recirculation of the air in the oven and the partial de-steaming of the baking chamber simultaneously, as the guide device can open up a plurality of the flow paths. This allows local accumulations of steam (steam nests) in the baking chamber, particularly in the corners, to be quickly eliminated and the moisture to be discharged via the chimney. This allows overall de-steaming to be carried out very effectively and quickly, so that energy can be saved during a baking process. It is also advantageous that the adjustable guide device can be flexibly adjusted. This means that the proportion of circulated air and the proportion of air escaping from the chimney can be flexibly adjusted to the respective baking requirements for different baking processes, each with its own baking requirements.

[0020] In practice, the described oven can be an oven with a static oven atmosphere and a plurality of radiators extending into the oven chamber. Ovens with a static baking atmosphere usually do not have a fan for heating the baked goods. The heating of baked goods in an oven with a static oven atmosphere can, for example, be achieved using a plurality of radiator plates heated with thermal oil. The radiator plates can be arranged at horizontal intervals in the baking chamber. Baked goods to be baked in such an oven can be heated in particular by the heat radiation from the radiator plates in a static oven atmosphere. The baked goods are often placed on stone plates located above the radiator plates, which additionally heat the baked goods through heat conduction.The radiators can, for example, be individually heated, so that such ovens can form a number of different heating zones in the baking chamber.

[0021] Since ovens with a static oven atmosphere generally do not require a fan to heat the baked goods, they generally do not have a guide device for controlling air flow. However, even when baking baked goods in an oven with a static oven atmosphere, it may be necessary to convey the air in the baking chamber, at least for a limited period of the baking process, for example, for the purpose of steam removal. By arranging the guide device for controlling the air flow in an oven with a static baking atmosphere, particularly gentle baking of the baked goods with high uniformity, low baking losses, and high energy efficiency is possible.

[0022] In practice, a commercial baking oven is usually equipped with a steam generator to generate steam, or steam vapor, in the baking chamber. The steam generator can be located in the baking chamber itself or in a separate steam generator, from which the steam is channeled to the baking chamber via steam ducts. The steam generator can be used to specifically increase the humidity in the baking chamber. It is particularly important that the humidity in the baking chamber is increased and then reduced again at precisely defined times during the baking process. Thus, the defined increase in humidity by the steam generator is just as important for baking success as targeted steam removal.

[0023] In practice, the guide device can be designed so that one of the following positions of the guide device can be assumed: a. the first flow path to the chimney is closed and the second flow path back to the baking chamber is opened so that the air in the baking chamber can be circulated; b. the first flow path to the chimney is open and the second flow path back into the baking chamber is closed, so that the air from the baking chamber can be discharged via the chimney and fresh air can be sucked into the baking chamber via the fresh air opening; c. the first flow path to the chimney and the second flow path back into the baking chamber are at least partially open so that the air in the baking chamber can be partially circulated and partially exchanged.

[0024] When the guide device is in position a, the air can be sucked in from the oven chamber, for example, by the fan, and transported into the main air duct. From the main air duct, the air can flow into the second flow path. At the outlet of the second flow path, the air can flow back into the oven chamber. This allows the air in the oven chamber to be recirculated.

[0025] If the guide device is in position b., the air can be sucked in from the baking chamber, for example by the fan, and transported into the main duct of the air duct. From the main duct of the air duct, the air can flow into the first flow path. At the outlet of the first flow path, the air can flow into the chimney, through which the air can escape into the environment. Fresh air from the environment can flow into the baking chamber via the fresh air opening. If a closing device is provided on the fresh air opening, this must be in an open position that at least partially uncovers the fresh air opening.

[0026] If the guide device is in position c., the air can be sucked in from the baking chamber, for example by the fan, and transported into the main duct of the air duct. From the main duct of the air duct, the air can flow in parts into the first and second flow paths. The air flow can be divided into any desired proportion. For example, 90% of the air flow can be directed into the first duct and 10% of the air flow into the second duct. Alternatively, for example, 10% of the air flow can be directed into the first duct and 90% of the air flow into the second duct. Further alternatively, for example, 50% of the air flow can be directed into the first duct and 50% of the air flow into the second duct.If a closure device is provided on the fresh air opening and this is in an (at least partially) open position, the air in the oven can be partially circulated via the second flow path (analogous to position a.) and partially replaced by fresh air via the first flow path (analogous to position b.).

[0027] The guide device is designed as a pivotable guide flap in the air duct. For example, the main duct of the air duct can be divided downstream into a first and a second secondary duct, wherein the first secondary duct forms the first flow path and the second secondary duct forms the second flow path, and the two secondary ducts are arranged adjacent to one another. The pivotable guide flap can then be arranged, for example, on a common dividing wall of the first and second secondary ducts, which borders the main duct, and protrude into the main duct. The guide flap can be arranged, in particular, via a pivot shaft, on the common dividing wall of the first and second secondary ducts, such that the guide flap is pivotable. Of course, the guide flap can also be arranged at any other location in the air duct that is suitable for the invention. For example, the guide flap can be arranged on the main duct.

[0028] Implementing the guide device as a guide flap is technically particularly simple and cost-effective. It requires only a few technical resources, so the probability of failure of the guide device is low. This is particularly important due to the aggressive properties of the air flowing through it (elevated temperatures and, in some cases, elevated humidity).

[0029] The guide device can be manually or electrically adjustable, allowing the air flow directed by the guide device to be distributed in a defined manner among the multiple flow paths. Manual adjustment can be achieved, for example, by locking the pivoting guide flap, which extends into the main duct, at predefined positions in the main duct using a manual actuating element, e.g., a lever.

[0030] In practice, it is particularly advantageous for electronically controlled ovens if the guide device can be adjusted via an electrically driven actuator. For this purpose, the actuator that can adjust the guide device can be a first actuator. The first actuator can be, for example, a stepper motor, an electric linear drive, or even a hydraulic cylinder. It can be located outside the air duct, particularly on the outside of the oven housing near the guide device, to be protected from direct exposure to the air flow. The first actuator can then adjust the guide device according to a predefined setting.If, for example, the guide device is designed as a pivoting guide flap and the first actuator as a first linear drive, the first linear drive can be connected to the guide flap via a linkage and can adjust the angle of attack of the guide flap relative to the air flowing along it by pushing or pulling. If the first linear drive is used to adjust the guide flap, it can also be used to lock the guide flap. In general, adjusting the guide device with an electric actuator has the advantage that the guide device can be continuously adjusted and locked. Furthermore, an electrically driven actuator can be controlled by the oven control system so that the position of the guide device can be adapted to the baking process.

[0031] In practice, a fan can be used that draws air from the oven chamber axially and expels it radially. Such radial fans achieve significant pressure increases in a small installation space. This allows the oven described above to be designed in a space-saving manner.

[0032] In practice, the second flow path, which guides the air back into the baking chamber, can be widened downstream. This means that the cross-sectional area of ​​the second flow path increases downstream, at least in a section of the second flow path. In particular, a section of the second flow path that borders the baking chamber in the flow direction can be widened downstream. As a result, the pressure of the air flow in the widened section of the second flow path decreases downstream, and the flow velocity of the air towards the baking chamber is reduced. In addition, the air can thus be guided into the baking chamber via a large passage area. If, for example, the oven atmosphere is circulated with the first flow path completely or partially closed, the oven atmosphere can remain as calm as possible, while the circulated air can be supplied to the baking chamber as homogeneously as possible.In this way, in a deck oven with radiators, where a static baking atmosphere is generally desired, improved heat transfer is achieved through air circulation without risking local overheating due to excessively high flow velocities.

[0033] Furthermore, baffles may be arranged in the widened section of the second flow path to homogenize the flow of the circulated air.

[0034] In practice, the fan and / or air duct can be located on a rear wall of the oven, i.e. on the side facing away from the oven door.

[0035] If the fan and / or the air duct are arranged on the rear wall of the oven, it has also proven suitable in practice to arrange ducts in the left and right side walls of the oven, through which ducts the air blown out by the fan can be directed to the front of the oven and from where it can be fed back into the baking chamber. For this purpose, the left and right side walls of the oven can be double-walled and ducts can be arranged in the double-walled wall. These ducts can represent sections of the second flow path. For example, the second flow path on the rear wall of the oven downstream of the guide device can be divided into two branches (e.g. a left and a right branch), and these two branches can be guided as ducts in the left and right side walls of the oven around the oven to the front of the oven.The ducts arranged in the left and right side walls can be widened vertically, particularly in the direction of flow, so that the recirculated air flowing back into the oven is directed across the entire height of the oven. This oven design allows for a large inflow cross-section for the air flowing back into the oven while maintaining a small installation space.

[0036] As explained above, a separate closing device can be assigned to the fresh air opening. In practice, this closing device can be electrically controllable. For this purpose, the closing device can, for example, comprise a movable cover plate and a second electrical actuator. The second actuator, like the first actuator, can be, for example, a stepper motor, a linear drive, or even a hydraulic cylinder. The cover plate can, in particular, be arranged in a control box which connects the fresh air opening directly or indirectly to the environment in a way that can be flowed through. The control box is, for example, arranged above the fresh air opening. The cover plate can be moved in the control box by the second linear drive such that a flow cross-section in the control box, through which fresh air flows from the environment to the fresh air opening, is either completely closed or completely open.Positions of the cover plate are also possible in which the flow cross-section is partially open.

[0037] Further practical embodiments and advantages of the invention are described below in conjunction with the drawings. Fig. 1 shows an oven according to the invention in a view obliquely from the rear. Fig. 2 shows a detailed view of an upper, rear area of ​​the oven from Fig. 1 in a view of the vertical section plane II. Fig. 3 shows a detailed view of a central area of ​​the oven from Fig. 1 in a view of the horizontal section plane III. Fig. 4 shows the oven Fig. 1 in a view from the rear without a side panel. Fig. 5 shows the oven Fig. 1 in a further embodiment in a view obliquely from the front.

[0038] The Fig. The oven 1 shown in Figure 1 has a rear wall 2, a right side wall 3 and a left side wall 4. An oven door 5 is arranged on the front side. The side references "left" and "right" apply to a viewer standing in front of the oven, looking at the oven door 5. The baking chamber 6 is accessible via the oven door 5 and can be loaded with baked goods. On the rear wall 2, the oven 1 has an air duct 7 formed by a sheet metal construction. A motor 8 is arranged on the air duct 7 and is connected via a shaft to an impeller of a fan 9 arranged in the air duct 7 (in Fig. 1 not shown). A first linear drive 10 forms a first actuator and serves in the illustrated oven 1 to change the position of a guide device 11 designed as a guide flap (in Fig. 1 not shown). For this purpose, the first linear drive 10 is mechanically connected to the guide flap 11 via a linkage 12. The first linear drive 10 is further arranged outside the air duct 7 and is fastened to the rear wall 2 of the oven 1, so that the first linear drive 10 is protected from the effects of air flowing in the air duct 7 and can exert a force on the guide flap 11. In Fig. 1 an exit 13 of the air duct 7 to a chimney can also be seen.

[0039] In Fig. 2 is the upper, rear area of ​​the oven 1 made of Fig. 1 is shown in detail as a sectional view. It can be seen that the described baking oven 1 has radiators 14 in the baking chamber 6, which can be heated, for example, with thermal oil and form a heating device. The radiators 14 are distributed vertically spaced apart in the baking chamber 6 and can be individually heated, so that a plurality of heating zones can be created in the baking chamber 6. Such a radiator baking oven 1, also called a trolley oven, typically does not have a fan for heating the baking chamber 6 and is operated in a static atmosphere.

[0040] A rear wall 15 of the baking chamber 6 is formed by a sheet metal with perforated holes 16. Through these holes 16, air located in the baking chamber 6 can flow from the respective heating zones of the baking chamber 6 into a connecting duct 17 arranged behind the baking chamber 6. The connecting duct 17 extends over the entire height of the baking chamber 6, allowing the air from the respective heating zones to mix and flow together to the air duct 7.

[0041] In Fig. 2 that the air duct 7 is arranged as a substantially closed, cuboid-shaped sheet metal construction on the rear wall 2 of the baking oven 1. In particular, the air duct 7 borders the connecting duct 17. The air duct 7 is divided into a main duct 18 and two secondary ducts 19 and 20. The main duct 18 forms a first section of the air duct 7 in the flow direction, into which air can flow from the connecting duct 17. The secondary ducts 19 and 20 are connected downstream and through the main duct 18. They are formed in the air duct 7 by a dividing plate 21 dividing the air duct 7 into two adjacent areas, which adjoin the main duct 18 in the direction of air flow. The first secondary duct 19 forms the first flow path and leads to a chimney. In the flow direction, the first secondary duct 19 has the outlet 13, to which the chimney can be connected.The second secondary duct 20 forms the second flow path and leads back to the baking chamber 6. So that air can be conveyed back into the baking chamber 6 via the second secondary duct 20 with as even a distribution as possible, the second secondary duct 20 is further divided downstream. For this purpose, an air distributor 22 is arranged in the second secondary duct 20. The air distributor 22 is formed by two metal sheets arranged at an angle to one another, each of which is oriented from the center of the rear wall 2 of the baking oven 1 to an upper, outer corner of the rear wall 2 of the baking oven 1. This allows the air in the second secondary duct 20 to be further divided. Downstream of the air distributor 22, the second secondary duct 20 leads around the baking oven 1 to its front side 5 and there opens back into the baking chamber 6. The second secondary duct 20 thus has sections that extend beyond the cuboid-shaped metal sheet construction of the air duct 7.Further details on the second secondary channel 20 are given below in connection with . Fig. 4 described.

[0042] As mentioned above, the air duct 7 borders the connecting duct 17. The sheet metal wall between the connecting duct 17 and the air duct 7 is interrupted in the region of an inlet opening 23. When the fan is in operation, air can be sucked from the connecting duct 17 via the inlet opening 23 through the impeller of the fan 9 into the air duct 7. The inlet opening 23 is designed as a round opening with curved side plates so that there is as little abrupt deflection of the air as possible when entering the air duct 7 from the connecting duct 17. This enables the air to enter the air duct 7 as smoothly as possible, without turbulence and / or (local) pressure losses. In the baking oven 1 shown in the figures, the impeller of the fan 9 is arranged directly behind the inlet opening 23, essentially congruent with the inlet opening 23 in the main duct 18.The impeller of the blower 9 is designed to draw in air in an axial direction and expel it radially. For this purpose, the impeller of the blower 9 is connected to the motor 8 of the blower via a shaft. The passage opening for the shaft into the air duct is sealed. The air expelled radially by the impeller of the blower 9 flows upward toward the secondary ducts 19 and 20.

[0043] At the transition from the main duct 18 to the secondary ducts 19 and 20, the guide device is designed as a guide flap 11. In particular, the guide flap 11 is attached to a pivot shaft 24, which is mounted on the sheet metal construction of the air duct 7 such that the side of the guide flap 11 on which the pivot shaft 24 is arranged borders the dividing plate 21. Thus, the guide flap 11 projects downwards into the main duct 18 and can be pivoted about the pivot shaft 24 relative to the direction of air flow in the air duct 7. Additionally, two frames 25, 26 are arranged in the main duct 18. A first frame 25 is adjacent to the first secondary duct 19 and is aligned obliquely to the direction of air flow. A second frame 26 is adjacent to the second secondary duct and is aligned obliquely to the direction of air flow.When the guide flap 11 is fully deflected in one direction, it rests flush on one of the two frames 25 or 26, so that when the guide flap 11 rests against the respective frame 25 or 26, no air can flow past the side of the guide flap 11 into the secondary duct 19 or 20. In the position shown in . Fig. In the position of the guide flap 11 shown in Figure 2, the guide flap 11 closes the first secondary duct 19 (i.e., it closes the first flow path to the chimney) by resting flush on the frame 25, which is arranged below the first secondary duct 19. The second secondary duct 20 (i.e., the flow path to the baking chamber 6) is open in this case. When air is conveyed into the air duct 7 by the fan 9, it flows at the Fig. 2, the deflection of the guide flap 11 is completely returned to the baking chamber 6 via the second secondary channel 20.

[0044] In Fig. Figure 3 shows a detailed sectional view of a central area of ​​the baking oven 1. The figure shows a device for adjusting the position of the guide flap 11. The pivot shaft 24 connected to the guide flap 11 projects rotatably out of the air duct 7 into the surrounding area through a small opening in the sheet metal construction of the air duct 7. There, the pivot shaft 24 is connected to the rod assembly 12 in such a way that the pivot shaft can be pivoted by the first linear drive 10 via the rod assembly 12 through an angular range of approximately 90°. In the first end position of the pivot shaft 24, the guide flap 11 rests against the first frame 25 and closes the first secondary duct 19. In the second end position of the pivot shaft 24, the guide flap 11 rests against the second frame 26 and closes the second secondary duct 20. In the positions between the first and second end positions, both secondary ducts are open to a certain extent.The first linear drive 10 is mounted on a bracket 27 arranged on the outside of the air duct 7. The above-described device comprising the first linear drive 10, the bracket 27, and the linkage 12 allows the guide flap 11 to be continuously controlled and locked. This device is particularly advantageous because the temperature-sensitive first linear drive 10 can be positioned at a suitable distance from the air duct 7. The drive is thus not affected by the heat radiated from the air duct 7.

[0045] The first linear drive 10 can also be connected to a digital oven control system (not shown), which also controls the other parameters of the baking process. Thus, the deflection of the guide flap 11 and the other parameters of the baking process can be coordinated.

[0046] In Fig. Figure 4 shows the described oven with the right side panel removed. It can be seen that the right side wall 3 is double-walled and formed from two parallel, spaced-apart sheets. The left side wall 4 is shaped analogously, as can be seen from Fig. 3. The space between the metal sheets of the right-hand side wall 3 and the space between the metal sheets of the left-hand side wall 4 form a continuation of the second secondary duct 20 (i.e. the second flow path) divided by the air distributor 22 in the direction of air flow. The spaces thus form channels and are part of the second secondary duct 20. If the air in the baking oven 1 is to be circulated, it is conveyed by the impeller of the fan 9 into the main duct 18 and guided by the guide flap 11 into the second secondary duct 20. At the air distributor 22, the air is evenly divided into a right and a left side. Via a right-hand deflector 28, the air is then guided downstream into the space between the metal sheets of the right-hand side wall 3 and via a left-hand deflector into the space between the metal sheets of the left-hand side wall 4.The right deflector 28 in the illustrated oven 1 is formed as a simple sheet metal construction that deflects the air within a duct section of the second secondary duct 20 around the baking chamber 6. The left deflector is formed analogously.

[0047] The extensions of the second secondary duct 20 in the right and left side walls 3 and 4 of the described oven 1 are widened downstream. From the rear wall 2 of the oven 1 toward its front side 5, the cross-sectional area of ​​these sections of the second secondary duct 20 increases vertically. When air flows through these sections, the flow velocity thus decreases in the direction of flow. At the outlets of the second secondary duct 20 facing the front of the oven 1, the air can flow into the baking chamber 6 at a low velocity.

[0048] In the right and left side walls 3 and 4, additional baffles 29 are arranged, whereby an air flow can be distributed evenly within the right and left side walls 3 and 4. The baffles extend over the entire width of the spaces between the sheets of the right and left side walls 3 and 4. The distances between the baffles increase in the flow direction, i.e., the baffles are arranged obliquely to one another.

[0049] In Fig. 1 shows that the oven 1 has a top wall 30. A fresh air opening 31 is provided in a front right area of ​​the top wall 30, through which fresh air from the environment can flow into the baking chamber 6. Fig.Figure 5 shows that the fresh air opening 31 is covered by a flange 32, to which a vertical inlet pipe 33 is connected. Adjacent to the inlet pipe 33 upstream is a control box 34, to which an intake nozzle 35 is connected further upstream. The fresh air opening 31, the flange 32, the inlet pipe 33, the control box 34, and the intake nozzle 35 are connected in a flow-through manner, so that fresh air from the environment can flow into the fresh air opening 31 and the baking chamber 6. A closure device 36 is arranged in the control box 34. The closure device 36 can be used to control a flow cross-section 37 of the inlet pipe 33 available for the flow of fresh air.

[0050] To control the flow cross-section 37, the closure device 36 comprises a cover plate 38 and a second linear drive 39, which forms a second actuator. The second linear drive 39 is electrically controllable. It is arranged on the outside of the control box 34 and is mechanically connected to the cover plate 38. The cover plate 38 can thus be displaced relative to the inlet pipe 33 by the second linear drive 39 in the control box 34 such that the flow cross-section 37 is covered or (partially) opened for fresh air.

[0051] The control box 34 is spaced from the top wall 30 of the oven 1 by the inlet pipe 33, allowing the second linear drive 39 to be positioned adjacent to the cover plate 38 without subjecting the second linear drive 39 to excessive heat load from the oven 1. By mounting the second linear drive 39 outside the control box 34, it can be easily replaced if it malfunctions.

[0052] The features of the invention disclosed in the present description, the drawings, and the claims may be essential, both individually and in any combination, for the realization of the invention in its various embodiments. The invention is not limited to the described embodiments. It may be varied within the scope of the claims and taking into account the knowledge of the person skilled in the art. List of reference symbols 1 oven 2 Back wall of the oven 3 right side wall of the oven 4 left side wall of the oven 5 Oven door 6 Baking chamber 7 Air duct 8 Engine 9 Impeller of a fan 10 first linear drive, first actuator 11 Guide device, guide flap 12 rods 13 Fireplace, exit to a fireplace 14 radiators, heating device 15 Rear wall of the baking chamber 16 holes 17 connecting channel 18 Main channel 19 first secondary channel, first flow path 20 second secondary channel, second flow path 21 Divider 22 air distributors 23 Inlet opening 24 Swivel shaft 25 first frame 26 second frame 27 Bracket 28 Deflection 29 baffles 30 Ceiling wall 31 Fresh air opening 32 flange 33 Inlet pipe 34 Control box 35 intake manifold 36 locking device 37 Flow cross-section 38 Cover plate 39 second linear drive, second actuator

Claims

[1] Oven (1) with - a baking chamber (6), - a heating device (14), - a fan (9) for conveying air in the baking chamber (6), - a chimney (13) through which the air from the baking chamber (6) can flow into the environment, and - a fresh air opening (31) through which air from the environment can flow into the baking chamber (6), characterized by in that the baking oven (1) has an air duct (7) in which the impeller of the fan (9) is arranged, wherein the air duct (7) has a plurality of flow paths (19, 20) downstream of the fan (9), of which a first flow path (19) leads to the chimney (13) and a second flow path (20) leads back into the baking chamber (6), and wherein a pivotable guide flap (11) is arranged in the air duct (7) which selectively guides the air from the fan (9) into at least one of the flow paths (19, 20). [2] Oven (1) according to claim 1, characterized bythat the oven (6) has a plurality of radiators (14) projecting into the baking chamber (6). [3] Oven (1) according to claim 1 or 2, characterized by a steam generator for generating steam in the baking chamber (6). [4] Oven (1) according to one of claims 1 to 3, characterized by that the guide flap (11) is designed so that one of the following positions can be assumed: a. the first flow path (19) to the chimney (13) is closed and the second flow path (20) back into the baking chamber (6) is opened so that the air in the baking chamber (6) can be circulated; b. the first flow path (19) to the chimney (13) is open and the second flow path (20) back into the baking chamber (6) is closed, so that the air from the baking chamber (6) can be discharged via the chimney (13) and fresh air can be sucked into the baking chamber (1) via the fresh air opening (31); c. the first flow path (19) to the chimney (13) and the second flow path (20) back into the baking chamber (6) are at least partially open, so that the air in the baking chamber (6) is partially circulated and partially exchanged. [5] Oven (1) according to one of claims 1 to 4, characterized by that the guide flap (11) is adjustable via a first linear drive (10). [6] Oven (1) according to one of claims 1 to 5, characterized by that the impeller of the fan (9) sucks in the air from the baking chamber (6) in an axial direction and blows it out in a radial direction. [7] Oven (1) according to one of claims 1 to 6, characterized by that the second flow path (20), which leads the air back into the baking chamber (6), is widened in the direction of flow. [8] Oven (1) according to one of claims 1 to 7, characterized by that the fan (9) and / or the air duct (7) are arranged on a rear wall (2) of the oven (1). [9] Oven (1) according to claim 8, characterized by that channels are arranged in the left and right side walls (3, 4) of the oven (1), through which the air blown out by the fan can be directed to the front of the oven (1) and into the baking chamber (6). [10] Oven (1) according to one of claims 1 to 9, characterized by that the fresh air opening (31) is assigned a closure device (36) with which the flow cross-section for the fresh air can be electronically controlled.

Images