WO1994016567A1

WO1994016567A1 - Forced-air baking cabinet

Info

Publication number: WO1994016567A1
Application number: PCT/CH1994/000012
Authority: WO
Inventors: Martin Schenk
Original assignee: Bafag Backofenfabrik Signau
Priority date: 1993-01-29
Filing date: 1994-01-25
Publication date: 1994-08-04

Abstract

In a forced-air baking cabinet (1) having a heat-insulated chamber (3) closed on all sides, a baking chamber (9) provided with two lateral damming walls (4, 5) and one upper cover (8) is arranged in the chamber (3). Both damming walls (4, 5) are provided with slots (13). A carriage (15) which carries superimposed baking trays (16) can be slid into the baking chamber (9). Above each baking tray is inserted in the carriage (15) an intermediate bottom (22), forming a first space (23) and a second space (24). The first space (23) and the second space (24) have lateral openings (25 and 26) adjacent to a respective slot (13) of the damming walls (4 or 5). The air flowing through the slots (13) may be led by adjusting means through the opening (25) into the first space (23) and/or through the opening (26) into the second space (24). The heat to which the top and the bottom of the products to be baked (17) are exposed may thus be regulated.

Description

Fan oven

The invention relates to a convection oven according to the preamble of claim 1.

Such baking barriers are known. In these baking barriers, the air contained therein is heated by heating elements in a room which is formed by the insulated housing of the baking cabinet, the front side of which is provided with a door. This heated air is circulated through fans in the form of a circuit. The baking chamber is formed by two storage walls, which run parallel to the insulated housing wall, and a cover. The baffle walls are provided with air passages through which the air can circulate. During the baking process, there is a trolley in the baking chamber, which is provided with several baking trays arranged one above the other, which can be pushed into the trolley, and on which the baking blanks are located.

The heated air now flows through the air passages of the one storage wall into the baking chamber, where it flows out between the sheets through to the other storage wall and out of the baking chamber through the air passages arranged in this other storage wall. Due to the overpressure behind the one storage wall and the negative pressure behind the other storage wall, a laminar, horizontally running flow is practically achieved in the baking chamber over its entire height.

In order to avoid that the baking blanks on the upstream side are baked faster than those on the downstream side, the flow direction of the air circuit is changed periodically. This will ensure even baking all baking blanks in the baking area are guaranteed.

This convection oven is very suitable for baked goods that have to be exposed to the same temperature on all sides. However, it is not suitable for baked goods that have to be baked with different top and bottom heat, since the top and bottom heat cannot be regulated.

So-called shooting ovens are used for baking baked goods that require different top and bottom heat. These normally consist of baking ovens arranged one above the other, each of which is self-contained and which can only accommodate one layer of baking trays. In these ovens, each can be regulated individually with regard to top and bottom heat.

However, these shooting ovens have the disadvantage that the trays filled with baked goods have to be pushed individually into the respective oven. The work involved is accordingly much greater than that of a baking cabinet in which the trolley equipped with sheets and baked goods can be inserted. In addition, these individual ovens arranged one above the other are considerably more expensive to purchase than a baking cabinet offering the same space.

The object of the invention is now to design a circulating air baking cabinet in such a way that the top and bottom heat for each individual baking sheet, which can be adjusted accordingly one above the other on the trolley which can be pushed into the baking cabinet.

According to the invention, this task is solved by the features specified in the characterizing part of claim 1.

Through the optional introduction and removal of the Warm air into or out of the first space, which is formed between the top of the baking sheet and the underside of the intermediate floor arranged above it, and / or into or out of the second space, which is arranged between the underside of the baking sheet and the one below ¬ neten intermediate floor is formed, the top and bottom heat can be regulated as required.

The intermediate floors are advantageously provided with standing bolts attached to the edge region, which bolts come to rest on guides, which ones

Guides run along the upper end of the angled profiles, which are attached to the carriage for receiving the baking trays. In this way, on the one hand the side openings are formed through which the warm air can flow, while on the other hand the intermediate floors can be removed from the carriage without any problems if no different top and bottom heat is required.

The air outlets in the baffle walls are advantageously designed as horizontally running slots, the height of a slot corresponding approximately to the height of one of the two openings of the first or of the second space, so that the slots are parallel and opposite to the two openings, which are also slit-shaped come to rest. One embodiment of the invention is that an adjustable baffle is arranged above and below each slot, which are provided in the storage wall. In an advantageous manner, all guide plates are correspondingly adjusted jointly via a control rod that can be moved by a drive. Depending on the position of the baffles, the air flows through the first room, which results in a high top heat, through the second room, which corresponds to a large bottom heat, or through both rooms, so that the baked goods to be baked is exposed to both top and bottom heat.

An advantageous embodiment of the invention is that the slots in the baffle walls and the openings on the carriage can be moved relative to one another. This can be done on the one hand by regulating the level of the carriage, or on the other hand by moving the two storage walls vertically. Advantageous refinements of this adjustment option result from the further dependent claims.

A further advantageous embodiment of the invention consists in the fact that two slots, which are arranged in the two storage walls, are at a mutual distance a from one another, while the distance between the baking trays inserted into the carriage is an integral multiple of each other Mass is a. This ensures that both trolleys with a small sheet spacing and trolleys with a large sheet spacing can be inserted into the baking cabinet, the top and bottom heat being adjustable in both cases, since the slots in the baffle walls that are not at the height of the Openings of the trolley are covered by the vertical leg of the profile, which is attached to the side of the trolley. Embodiments of the invention are explained in more detail below by way of example with reference to the accompanying drawings. It shows

1 is a side view in section of the air-circulating oven cabinet;

2 shows a detail from a side view of the carriage;

Fig. 3 shows a detail of a view of a Storage wall with adjoining area of the carriage, with maximum upper heat set;

FIG. 4 is a view of a section of the storage wall according to FIG. 3 with the adjacent area of the carriage, with the maximum bottom heat set;

5 schematically shows the adjustability of the guide plates according to FIGS. 3 and 4;

6 shows a view of a section of a storage wall with the region of the wagon adjoining it, with a height adjustable relative to one another, set for maximum top heat;

FIG. 7 shows a detail of a view of the storage wall with an adjacent area of the carriage according to FIG. 6, set for maximum bottom heat; Fig. 8 is a side view of the upper portion of the

Baking cupboards cut along the length of the baking cupboard with a height-adjustable storage wall;

9 is a sectional view along line IX-IX through the dam wall according to FIG. 8.

The circulating air baking cabinet 1 according to FIG. 1 is formed by heat-insulated side walls 2 which enclose a space 3 on all sides. In a known manner, the front side, not shown, is designed as a door. In parallel to the heat-insulated side walls 2, a baffle wall 4 or 5 is arranged. These two baffle walls 4 and 5 are spaced apart from the corresponding side walls 2, so that an air duct 6 and 7 is formed between the side walls 2 and the corresponding baffle wall 4 and 5, respectively. The two storage walls 4 and 5 run from the front of the circulating air baking cabinet 1 to the rear side thereof.

The two baffle walls 4 and 5 are provided with an upper cover 8, which covers the two baffle walls. de 4 and 5 is placed and has the same length. The baking chamber 9 is formed in the room 3 by the two baffle walls 4 and 5 and the cover 8.

3, fans 10 and a heating element 11 are installed in the room above the cover 8. The fans 10 can be driven via corresponding motors 12. Air passages in the form of slots 13 are let into the baffle walls 4 and 5, so that, for example, the air, driven by the fan 10 arranged on the left in FIG. 1, along arrow 14 from the heating element 11 into the air duct 6 through the slots 13 of the baffle 4 is passed into the baking chamber 9, from where the air flows out via the slots 13 of the baffle 5 into the air duct 7 and from there back to the heating element 11. By switching off the fan 10 arranged on the left in FIG. 1 and switching on the fan 10 arranged on the right, the direction of flow of the air circuit is reversed. Such a switchover is carried out periodically so that an even heat distribution takes place in the baking chamber 9.

A carriage 15 can be moved into the baking chamber 9, on which baking trays 16 arranged one above the other are inserted. The baking blanks 17 are arranged on the baking trays 16. To accommodate the baking trays 16 in the carriage 15, horizontally extending angled profiles 18 are attached to the sides. As can be seen from FIG. 3, these angular profiles 18 have a horizontal leg 19 on which the baking trays 16 can be inserted. A guide 21 is formed on each of the upper edges of the vertical legs 20 of the angled profiles 18, into which an intermediate floor 22 can be inserted. Between the top of each baking tray 16 and the bottom of the one arranged above it Intermediate base 22 creates a first space 23. A second space 24 is created between each underside of baking sheet 16 and the upper side of intermediate base 22 arranged underneath. In the edge area of intermediate base 22 there is first space 23 and second space 24 with an opening 25 or 26 provided, which come to lie at the height of the associated slot 13 of the two baffle walls 4 and 5.

In the side view of a section of one side of the carriage 15 according to FIG. 2, the vertical legs 20 of the angular profile 18 can be seen. The vertical legs 20 of these angled profiles 18 form the side wall of the carriage 15. This side wall is only penetrated by the openings 25 and 26, which openings 25 and 26 are the inlet and outlet for the air into the first space 23 and second room 24 form the. To reach the opening 25, the intermediate floor 22 is equipped at the edge area with standing bolts 27, which bolts 27 are supported on the guides 21 of the angled profiles 18.

As can be seen from FIG. 3, the height h of the two openings 25 and 26, which are slot-shaped, corresponds approximately to the height H of the slots 13, which are arranged in the baffle walls 4 and 5. In order to be able to direct the air flowing through the slots 13 of the baffle walls 4 and 5 through one of the two openings 25 or 26, the slats 28 which form the corresponding baffle walls 4 and 5 are at their upper and lower edge regions equipped with baffles 29. In the position of the guide plates 29, as shown in FIG. 3, the air which flows through the slots 13 is conducted through the openings 25 into the first space 23, as shown by arrow 30. On the opposite side, not shown, which is wall 5 is formed, the corresponding baffles are placed symmetrically, as a result of which the air flows out of the first space 23 through the baffles 29 into the air duct 7. In this position of the guide plates, the first space 23 is thus provided with warm air, ie the baking blanks 17 are exposed to an upper heat.

By changing the guide plates 29 from the position shown in FIG. 3 to the position as shown in FIG. 4, the air flowing through the slots 13 of the corresponding baffle walls 4 and 5 is passed through the opening tion 26 passed into the second space 24, represented by arrow 31. This means that the baking blanks 17 are exposed to a lower heat.

Between the two extreme positions of the guide plate 29, as shown in FIGS. 3 and 4, and with which a maximum upper heat or a maximum lower heat is achieved, intermediate positions can also be set. This means that the baking blanks can be exposed to both top and bottom heat as required.

As can be seen from FIG. 5, the guide plates 29 are provided at their front ends and, as required, distributed over the length with tabs 31 arranged at right angles to the guide plates 29. These tabs 31 can be pivoted about a longitudinal axis 32 running along the corresponding lamella 28. Each of the end plates 31 of the guide plates 29 are equipped with a pivot lever 33. The pivoting levers 33 arranged in series one below the other are articulated to a control rod 34, which control rod can be moved in the direction of the double arrow 35 in a manner not shown but known via a drive.

The optional supply and discharge of warm air through the slots 13 of the two baffle walls 4 and 5 into the opening The opening 25 and / or the opening 26 can also take place in that the slots 13 and the openings 25 and 26 of the carriage 15 made in the baffle walls 4 and 5 can be displaced relative to one another, as can be seen from FIGS. 6 and 7 is. In the position according to FIG. 6, the slots 13 are at the level of the opposite openings 25. As a result, the air which flows through the slots 13 of the two retaining walls 4 and 5 is in each case in the first space 23 opening 25 is directed as indicated by arrow 36. This means that the baking blanks 17, which are located on the baking trays 16 inserted into the carriage 15, are exposed to an upper heat.

7 shows the position in which the openings 26 are directly opposite the slots 13 of the baffle walls 4 and 5. This means that the baffle walls 4 and 5 and the carriage 15 have been displaced in height relative to one another. In this position, the openings 25 are essentially covered by the lamellae 28 of the two baffle walls 4 and 5. The air flowing through the slots 13 thus reaches the second space 24, as a result of which the baking blanks 17 are exposed to a lower heat. The air flow is shown by arrow 37.

6 and 7 each show the two extreme positions, intermediate positions can also be set, as a result of which the air can flow both through the opening 25 into the first space 23 and through the opening 26 into the second space 24 . Here, the baking blanks 17 are exposed to top and bottom heat.

The relative displacement between the storage walls 4 and 5 and the carriage 15 can be carried out according to a first variant, which is shown in FIG. 1. The carriage 15 inserted into the baking chamber 9 is suspended from its upper four corners on an element 38, for example a wire rope, in a manner which is not shown but is known. The elements 38 are led vertically upwards out of the space 6 through openings in the cover and in the insulated upper side wall. The elements 38 are then fed via deflecting rollers 39 to a pivotable shaft 40 which is mounted on the circulating air baking cabinet 1. The winding direction of all elements 38 on shaft 40 is directed in the same direction. The shaft 40 is equipped with a lever 41 on which a linear drive 42 articulated on the circulating air oven 1 is articulated. By actuating the linear drive 42, the shaft 40 is pivoted, all the elements 38 which are fastened thereon are wound up or unwound depending on the pivoting direction, as a result of which the carriage 15 is raised or lowered accordingly. The corresponding top and bottom heat can be regulated by correspondingly raising or lowering the carriage, as described above.

The second variant for the relative adjustment between the slots 13 of the baffle walls 4 and 5 and the carriage 15 can, as shown in FIG. 8, be achieved by vertically shifting the two baffle walls 4 and 5. The slats 28 are each on their front ends are attached to a profile 43 and 44, so that a slot 13 is formed between the individual slats 28. The baffles 4 and 5 thus formed lie with their profiles 43 and 44 in a vertical guide 45 and 46 which are fastened in the convection oven 1. Each profile 43 and 44 is connected at its upper end to an element 47, which element can be designed as a wire rope. Each element 47 is identified by a vertically arranged tube 48, which penetrates the cover 8 and the upper side wall of the convection oven 1, out of the room 3. For each element 47, a deflection roller 49 is fastened on the upper side wall of the circulating air oven 1, over which the element 47 is guided. All elements 47 end on a rotatable shaft 50, with which they are fastened in such a way that the winding direction is the same. The rotatable shaft 50 is held stationary on the circulating air oven 1. A lever 51 is fastened to the rotatable shaft 50, to which one end of a linear drive 52 is articulated, the other end of which is pivotally connected to the circulating air oven 1. By actuating the linear drive 52, the rotatable shaft 50 is rotated, as a result of which the elements 47 attached to it are wound up or unwound, with the result that the two retaining walls 4 and 5 are raised or lowered. The position of the slots 13 with respect to the openings 25 and 26 of the carriage can thereby be adjusted. In the sectional view according to FIG. 9 it can be seen how the slats 28 are fastened to the profiles 43 and 44, which are designed as square profiles, and how these two square profiles 43 and 44 in the guides 45 and 46, which as U-profiles are designed and fastened in the baking cabinet 1 accordingly.

As can be seen from FIG. 8, two horizontal slots 13 of the storage wall 4 and 5 are at a mutual distance a. Depending on the size of the baking blanks 17 to be baked, for example a carriage 15 is equipped such that two baking trays 16 are at a distance 2a, while in a second carriage the distance between the baking trays 3a and in a third carriage the distance between the baking trays 4a. As already mentioned, the Slots 13, which are not at the level of the openings 25 and 26 of the baking trolley, are covered by the vertical leg 20 of the angled profiles 18. In the above-mentioned division of the distances between the baking trays 16, the baffle walls 4 and 5 can now be equipped such that the first slot can be omitted from below, that the second, third and fourth slots must be provided, that the fifth Slot can be omitted again, while the sixth slot must be present. Then this period starts again.

The circulating air baking cabinet 1 is equipped, in a manner which is not shown, but is known, with a steam regulator with which the steam content of the air in the room 3 can be regulated accordingly.

So that the regulation of the top and bottom heat is still ensured during a longer baking time, the intermediate floor 22 can be provided with a heat-insulating layer.

Claims

1. Recirculating air baking cabinet, which comprises a heat-insulated, all-round enclosed space, in which a front side is designed as a door, in which space parallel to the side walls, spaced from them and provided with air passages, are arranged storage walls , which are provided with an upper cover which, together with the baffle walls, form the baking space, into which a trolley loaded with baking trays can be inserted through the front, in which space at least one heating element and at least one fan is arranged outside the baking space Which fan the air heated by the heating element flows through the air passages of one of the two baffle walls into the baking chamber and through the air passages of the other of the two baffle walls out of the baking chamber, characterized in that in the carriage (15) above each baking sheet (16 ) an intermediate floor (22) is inserted, so that in each case between the top of the back sheet Echs (16) and the underside of the intermediate floor (22) arranged above it a first space (23) and between the underside of the baking sheet (16) and the intermediate floor (22) arranged underneath a second space (24) that the first space (23) and the second space (24) have openings (25) and (26) in the sides adjacent to the two storage walls (4) and (5), and that means are provided with which the warm air flowing through the baffle walls (4) and (5) can optionally be conducted through the first room (23) and / or the second room (24).

2. Air-circulating baking cabinet according to claim 1, characterized in that on the sides of the carriage (15) running parallel to the baffle walls (4), (5), essentially horizontally arranged angular profiles (18) are attached, on the horizontal of which Legs (19) the baking trays (16) can be pushed in, while along the edges of the vertical legs (20) guides (21) are fitted, into which guides (21) the intermediate floors (22) can be pushed, the intermediate floors (22) are provided with standing bolts (27) attached to the edge region, which bolts (27) are supported on the guides (21), as a result of which the opening (25) is formed between the intermediate floors (22) and the angular profiles (18) .

3. Recirculating air baking cabinet according to one of claims 1 or 2, characterized in that the air passages in the baffle walls (4, 5) are designed as essentially horizontal slots (13), the height (H) of which is approximately the height (h). one of the two openings (25) or (26) corresponds.

4. Recirculating air baking cabinet according to one of claims 1 to 3, characterized in that the means consist of adjustable baffles (29) which form above and below the baffle walls (4, 5), with mutually spaced lamellae ( 28) are arranged, each guide plate (29) being pivotable about a longitudinal axis (32) running along the corresponding lamella (28).

5. circulating air oven according to claim 5, characterized in that each baffle (29) with a

Swivel lever (33) is equipped, which swivel lever (33) are articulated on at least one control rod (34) and that the at least one control rod (34) can be moved via a drive.

6. Circulating air baking cabinet according to one of claims 1 to 3, characterized in that the means consist of a hanging device on which the carriage (15) inserted into the circulating air baking cabinet (1) can be suspended and its height adjustable, whereby the position of the openings (25) or (26) of the first rooms (23) and second rooms (24) with respect to the air passages (13) of the baffle walls (4, 5) can be changed.

7. A convection oven according to claim 6, characterized in that the hanging device consists of at least one element (38) of finite length which can be suspended on the carriage (15) and which is connected to an adjustment mechanism (40, 41). which adjustment mechanism (40, 41) can be actuated via a linear drive (42).

8. convection oven according to one of claims 1 to 3, characterized in that both baffle walls (4,

5) consist of lamellae (28) arranged one above the other with a space in the form of a slot (13), which acts as an air passage, which lamellae (28) each have a profile (43) in the front and rear end regions. (44), and that the two lamella walls thus formed are guided essentially vertically displaceably in the end-side guides (45) and (46) fastened to the baking cabinet, and that the displacement of the lamella walls is carried out by means of an adjustment mechanism ( 50, 51).

9. A convection oven according to claim 8, characterized in that the adjusting mechanism consists of a shaft (50) which can be rotated about its longitudinal axis, which shaft (50) can be rotated via a linear drive (52), and that on the shaft (50 ) the ends of at least two flexible elements (47) of finite length are fastened, while the other ends of the flexible elements (47), which are guided over deflection rollers (49), are fastened to a point on each of the two lamella walls.

10. A convection oven according to one of claims 1 to 9, characterized in that in each case two air passages of the two storage walls (4, 5) formed as horizontal slots (13) are at a mutual distance (a) from one another, and that the distance the baking trays (16) from one another, when they are pushed into the carriage (15), is an integral multiple of the dimension (a).