The invention relates to a baking oven comprising a continuous baking belt, which revolves in longitudinal direction of the baking oven, wherein a front belt deflecting station, an input station, a baking chamber, an output station and a rear belt deflecting station are arranged behind one another in longitudinal direction of the baking oven. The upper run of the baking belt is arranged in an upper transport plane and extends backwards from the front belt deflecting station through the input station, the baking chamber and through the output station to the rear belt deflecting station. The lower run of the baking belt extends forwards from the rear belt deflecting station below the baking chamber to the front belt deflecting station. The baking chamber is arranged in a housing, which is provided with an outer heat insulation and which is supported by an oven frame. The baking oven is provided with a belt preheating device, which is arranged on the circumferential path of the baking belt outside of the baking chamber.
Baking ovens, in the case of which a continuous baking belt revolves in longitudinal direction of the baking oven, are used in the food industry for producing all kinds of baked goods. Such baked goods are, e.g., flat cookies, crunchy crackers, but also small baked goods, cakes, breads, sandwich loaves, etc.
To produce the baked goods, pieces of dough, which consist of raw dough and which have already been brought into the form that corresponds to the respective baked goods, are fed to the baking oven. The pieces of dough are placed onto the baking belt at the input station and are conveyed into the baking chamber by means of the baking belt. The pieces of dough are baked in the baking chamber. The baking belt conveys the baked pieces of dough to the output station. In the output station, the baked pieces of dough are removed from the baking belt as completely baked goods.
Baking ovens, which are equipped with a belt preheating device, in which the revolving baking belt is heated before it reaches the input station of the baking oven, are used for the production of cookies and crackers. In the input station, the raw pieces of dough are placed onto the heated or preheated baking belt, respectively. The raw pieces of dough are heated by means of the preheated baking belt. The preheated pieces of dough are conveyed into the baking chamber of the baking oven by means of the baking belt and are subjected to high baking temperatures at that location.
Belt preheating devices, which are equipped with gas burners and which are arranged in the oven frame below the baking chamber and which are provided with a heat insulation at least on the upper side, are used in the case of known baking ovens for producing cookies and crackers. The heat insulation, which is arranged on the upper side of the belt preheating device, prevents the housing of the baking oven, which is arranged above the belt preheating device and which contains the baking chamber, is heated from below by the heat, which is generated in the belt preheating device. The baking belt is heated directly in the belt preheating device by means of the flue gases of the gas burners. The interior of the belt preheating device is filled with hot flue gases. The flue gases of the gas burners are discharged from the belt preheating device via lateral flue ducts.
It is the object of the invention to specify an improved baking oven, which has a continuous baking belt, which revolves in longitudinal direction of the baking oven and which is equipped with a belt preheating device.
As solution, the invention proposes a new baking oven. The latter is provided with a continuous baking belt, which revolves in longitudinal direction of the baking oven. In the case of the new baking oven, a front belt deflecting station, an input station, a baking chamber, an output station and a rear belt deflecting station are arranged behind one another in longitudinal direction of the baking oven. The upper run of the baking belt is arranged in an upper transport plane and extends backwards from the front belt deflecting station through the input station, the baking chamber and through the output station to the rear belt deflecting station. The lower run of the baking belt extends forwards from the rear belt deflecting station below the baking chamber to the front belt deflecting station. The baking chamber is arranged in a housing, which is provided with an outer heat insulation and which is supported by an oven frame. The new baking oven is provided with a belt preheating device, which is arranged on the circumferential path of the baking belt outside of the baking chamber.
According to the invention, the new baking oven is characterized by the following features. The baking belt is embodied as a susceptor, which can be heated inductively to the belt preheating temperature in a contactless manner. The baking oven has an inductive belt preheater, which is embodied as electrical induction heater. The inductive belt preheater has at least one extensive inductor, which is arranged in the belt preheating device and which is arranged adjacent to the baking belt and the baking belt, which passes it and which is embodied as a susceptor, is heated inductively to the belt preheating temperature in a contactless manner and thus generates the belt preheating by means of the extensive magnetic field generated by said inductor.
The baking oven according to the invention has a baking belt, which is embodied as a susceptor, which can be heated inductively in a contactless manner and which can be heated inductively to the relatively high belt preheating temperature. The belt preheating temperature is adjusted to the baking process, which is to be realized in the baking oven and is predetermined by it. In the belt preheating device, the baking belt is heated inductively to the relatively high belt preheating temperature. The belt temperature, which is generated inductively in the belt preheating device, is chosen to be very high, so that the inductively heated, hot baking belt arrives in the input station with a belt temperature, which is sufficient for heating the pieces of dough, which are placed onto the hot baking belt. The belt section of the baking belt, which is inductively heated in the belt preheating device, is conveyed to the input station of the baking oven by means of the revolving movement of the baking belt. There, the raw pieces of dough are placed onto the hot belt section and are heated slightly by the latter before they are conveyed into the baking chamber of the baking oven by means of the baking belt.
In the case of the embodiment of the baking oven according to the invention, the baking belt is heated inductively in a contactless manner in the belt preheating device and is thereby heated inductively to the relatively high belt preheating temperature. The inductive heating of the baking belt generates considerably lower room temperatures in the belt preheating device than does the heating of the baking belt by means of the flue gases of gas burners provided in the case of a conventional belt preheating device. In the case of the baking oven according to the invention, the heat insulation required at the outside of the belt preheating device can be reduced considerably and can thus be designed more cost efficiently than in the case of a conventional belt preheating device, which is equipped with gas burners.
In the case of the baking oven according to the invention, the electrical induction heater, which is provided for the belt preheating, can be embodied with a relatively high degree of efficiency (up to 0.79), which lies considerably above the degree of efficiency of a belt preheating by means of a gas burner (only 0.33).
The embodiment of the baking oven according to the invention allows it to considerably reduce the overall length of the belt preheating device, measured in longitudinal direction of the baking belt, as compared to a belt preheating device, which is equipped with gas burners, because the extensive inductor of the inductive belt preheater, which is arranged in the belt preheating device in the case of the baking oven according to the invention, requires a considerably shorter belt section for inductively heating the baking belt than does the belt preheating device, which is equipped with gas burners.
The baking belt of the baking oven according to the invention is embodied as a susceptor, which can be heated inductively in a contactless manner and which can be heated inductively to the relatively high belt preheating temperature. This susceptor belt can be embodied in different ways.
The susceptor belt can be embodied as a wire conveyor belt consisting of wire pieces, which has a high mass density. The wire conveyor belt can be embodied as a woven wire mesh belt, flat link belt, multi-spiral belt, etc. In the case of the susceptor belt, which is embodied as a wire conveyor belt, the wire pieces are arranged closely next to one another, the spaces between the wire pieces are small and the cross section of the wire pieces is relatively large. This leads to a high mass density of the wire conveyor belt. In the case of a susceptor belt, which is embodied as a wire conveyor belt, a minimum weight of 18 kg per each meter of belt length is preferred. The susceptor belt, which is embodied as a wire conveyor belt, can also encompass a higher belt weight than 18 kg per each meter of belt length.
The susceptor belt can also be embodied as a plate belt, which encompasses a high mass density. The plate belt can be embodied as a hinged plate belt or as a continuous steel plate belt, the steel plates of which are fastened to lateral transport chains. In the case of the susceptor belt, which is embodied as a plate belt, the high mass density is attained by means of the relatively large thickness of the plates, which consist of iron or steel, respectively. In the case of the susceptor belt, which is embodied as a plate belt, a minimum weight of 18 kg per each meter of belt length is preferred. The susceptor belt, which is embodied as a plate belt, can also encompass a higher belt weight of 20 kg and more for each meter of belt length.
According to a further feature of the invention, provision can be made for a lower belt preheating device to be provided, which is arranged on the lower run of the baking belt and in which an extensive inductor of the inductive belt preheater is arranged, which inductively heats the lower run of the baking belt, which moves past it, to the belt preheating temperature in a contactless manner and thus generates the belt preheating by means of the extensive magnetic field generated by said inductor.
According to a further feature of the invention, provision can be made for the lower belt preheating device, which is arranged on the lower run of the baking belt and which includes an extensive inductor of the inductive belt preheater, to be arranged below the input station of the baking oven.
According to a further feature of the invention, provision can be made for the lower belt preheating device, which is arranged on the lower run of the baking belt and which includes an extensive inductor of the inductive belt preheater, to be arranged in the oven frame below the baking chamber.
According to a further feature of the invention, provision can be made in the lower belt preheating device for an extensive inductor of the inductive belt preheater, which is arranged below the lower run of the baking belt and which inductively heats the lower run of the baking belt, which moves past the top of it, to the belt preheating temperature in a contactless manner and thus generates the belt preheating by means of the magnetic field generated by said inductor.
According to a further feature of the invention, provision can be made in the lower belt preheating device above the lower run of the baking belt for an extensive inductor of the inductive belt preheater to be arranged, which inductively heats the lower run of the baking belt, which moves past the bottom it, to the belt preheating temperature in a contactless manner and thus generates the belt preheating by means of the magnetic field generated by said inductor.
According to a further feature of the invention, provision can be made in the lower belt preheating device above and below the lower run of the baking belt for an extensive inductor of the inductive belt preheater, wherein the magnetic fields generated by the two inductors inductively heat the lower run of the baking belt, which passes between the inductors, to the belt preheating temperature in a contactless manner and thus generate the belt preheating.
According to a further feature of the invention, provision can be made in the lower belt preheating device for an extensive inductor of the inductive belt preheater, which is embodied in a C-shaped manner, which overlaps the lower run of the baking belt with horizontal sections on the upper side and the lower side and which inductively heats the lower run of the baking belt, which passes between its horizontal sections, to the belt preheating temperature in a contactless manner and thus generates the belt preheating.
According to a further feature of the invention, provision can be made in the lower belt preheating device for an extensive inductor of the inductive belt preheater, which overlaps the lower run of the baking belt and which has vertical sections, which are arranged laterally at a distance from the side edges of the baking belt and horizontal sections, which are adjacent to the upper side or the lower side, respectively, of the baking belt, wherein only the horizontal sections of the inductor inductively heat the lower run of the baking belt, which passes through the inductor, to the belt preheating temperature in a contactless manner and thus generate the belt preheating by means of the magnetic fields generated by said inductor.
According to a further feature of the invention, provision can be made for an upper belt preheating device to be provided, which is arranged adjacent to the section of the baking belt arranged in the input station and in which an extensive inductor of the inductive belt preheater is arranged, which inductively heats the baking belt, which is embodied as a susceptor, to the belt preheating temperature in a contactless manner and thus generates the belt preheating by means of the magnetic field generated by said inductor.
According to a further feature of the invention, provision can be made for the upper belt preheating device to include an extensive inductor of the inductive belt preheater, which is arranged below the baking belt and which inductively heats the baking belt, which is embodied as a susceptor and which moves past it on the top, to the belt preheating temperature in a contactless manner and thus generates the belt preheating by means of the magnetic field generated by said inductor.
According to a further feature of the invention, provision can be made for the baking belt, which is embodied as a susceptor and which can be heated inductively to the belt preheating temperature in a contactless manner by means of an electrical induction heater, to be a heavy baking belt comprising a high mass density, chosen from the group: (1) wire conveyor belts, (2) woven wire mesh belts, (3) round link belts, (4) multi-spiral belts, (5) flat link belts, and (6) hinged plate belts.
The invention will be defined in more detail below by means of exemplary embodiments illustrated in the drawings.
The continuous belt 2 revolves in the baking oven 1 in the longitudinal direction thereof. The upper run 2a of the baking belt 2 is arranged in an upper transport plane and moves in the latter from the front belt deflecting station 3 to the input station 4 and then through the input station 3, through the baking chamber arranged in the housing 5 and through the output station 6 to the rear belt deflecting station 7 of the baking oven 1. The lower run 2b of the baking belt 2, which is arranged below the upper run 2a, moves back towards the front from the rear belt deflecting station 4 of the baking oven 1 to the front belt deflecting station 3 of the baking oven 1.
The baking chamber and the baking chamber heater of the baking oven 1, which encompasses a plurality of heating elements 8, are accommodated in the elongated housing 5. The housing 5 is provided with an outer heat insulation, which extends across the entire length of the housing 5. The housing 5 is supported by the oven frame 9 of the baking oven 1. The oven frame 9 has vertical feet 10, which support the housing 5 on the ground at the set-up location of the baking oven 1. The feet 10 are arranged on the side edges of the housing 5 and form two rows of feet, which run in longitudinal direction of the baking oven 1. The lower run 2b of the baking belt 2 is arranged below the housing 1 between the two rows of feet.
During the operation of the baking oven 1, the continuous baking belt 2 revolves in longitudinal direction of the baking oven 1. In the input station 4, raw pieces of dough are placed onto the upper run 2a of the baking belt 2 and are conveyed through the baking chamber arranged in the housing 5 by means of the baking belt 2. The pieces of dough are baked in the baking chamber. The revolving baking belt 2 conveys the baked pieces of dough to the output station 6 of the baking oven 1. In the output station 6, the baked pieces of dough are removed from the baking belt 2 as completely baked goods.
The baking oven 1 has a belt preheating device 11, which is arranged on the circumferential path of the baking belt 2 and in which the baking belt 2, which passes this device 11, is heated to a relatively high belt temperature, so that the baking belt 2 arrives at the input station 4 in the heated state, in which the raw pieces of dough are then placed onto the already heated, hot baking belt 2 and are subsequently heated by means of the hot baking belt 2. The pieces of dough, which have been heated by the hot baking belt 2, but which are still raw, are conveyed into the baking chamber, which has been heated to high baking temperatures by means of the baking chamber heater of the baking oven 1, by means of the hot baking belt 2. The pieces of dough preheated on the hot baking belt 2 are baked completely while passing through the baking chamber. The baked pieces of dough are then removed from the upper run 2a of the baking belt 2 as completely baked goods at the output station 6. Baked goods, which are identified as crackers or hard cookies, e.g., can thus be produced in the baking oven 1.
The baking oven 1 has a lower belt preheating device 11, which is assigned to the lower run 2b of the baking belt 2. Said preheating device 11 is arranged on the front side of the housing 5 in the space between the front belt deflecting station 3 and the housing 5 and heats the baking belt 2 at its lower run 2b. The heated, hot belt section of the baking belt 2 passes the front belt deflecting station 3 and is conveyed into the input station 4 by means of the revolving movement of the baking belt 2.
The baking belt 2 of the baking oven 1 is embodied as a continuous susceptor belt, which can be heated inductively to high belt temperatures in a contactless manner by means of an electrical induction heater in a contactless manner, which can be heated inductively to high belt temperatures.
The baking oven 1 is equipped with an inductive belt preheater, which is embodied as an electrical induction heater. The electrical induction heater provides for an alternating current generator 12, which is connected via current lines to an extensive inductor 13, which is arranged in the lower belt preheating device 11 and which inductively heats the lower run 2b of the baking belt 2 in a contactless manner by means of the extensive magnetic field generated by said inductor. The baking belt 2 is heated inductively to high belt temperatures in the lower belt preheating device 11. The high belt temperatures are in the range of the relatively high belt preheating temperatures from xx to yy degrees Celsius, which are predetermined by a cracker baking process, e.g.
In the case of the baking oven 14, a front belt deflecting station 15, an input station 16, an elongated housing 19, which includes the baking chamber 17 and the baking chamber heater 18, an output station 20 and a rear belt deflecting station 21 are arranged behind one another in longitudinal direction. The baking oven 14 has a continuous baking belt 22, which revolves in longitudinal direction of the baking oven 14 from the front belt deflecting station 15 to the rear belt deflecting station 21. The upper run of the baking belt 22 is arranged in an upper transport plane and moves therein from the front belt deflecting station 15 to the input station 16 and then through the input station 16, through the baking chamber 17 arranged in the housing 19 and through the output station 20 to the rear belt deflecting station 21.
The baking oven 14 has a lower belt preheating device 23, which is arranged between the front belt deflecting station 15 and the housing 19. The revolving baking belt 22 passes the lower belt preheating device 23 with its lower run 22b and is heated there to high belt temperatures. The hot belt section of the revolving baking belt 22, which has been heated in the lower belt preheating device 23, passes the front belt deflecting station 15 and is conveyed into the input station 16 by means of the revolving movement of the baking belt 22.
The baking belt 22 is embodied as a continuous susceptor belt, which can be heated inductively to high belt temperatures in a contactless manner by means of an electrical induction heater in a contactless manner and can be heated inductively to high belt temperatures.
The baking oven 14 is equipped with an inductive belt preheater, which is embodied as electrical induction heater. The electrical induction heater provides for an alternating current generator 24, which is connected via current lines to an extensive inductor 25, which is arranged in the lower belt preheating device 23 and which inductively heats the baking belt 22 in a contactless manner by means of the extensive magnetic field generated by said inductor. The inductor 25 or the magnetic field generated by it, respectively, heats the baking belt 22 inductively to high belt temperatures in a contactless manner. The high belt temperatures, which are generated in the baking belt 22 by the electrical induction heater via the inductor 25 are in the range of the relatively high belt preheating temperatures from xx to yy degrees Celsius, which are predetermined by a cracker baking process, e.g.
The baking belt 27 is embodied as a continuous susceptor belt, which can be heated inductively to high belt temperatures in a contactless manner by means of an electrical induction heater.
The baking oven 26 is equipped with an inductive belt preheater, which is embodied as an electrical induction heater. The alternating current generator of the induction heater is connected to an extensive inductor 33 via current lines. The inductor 33 is arranged in a belt preheating device 34, which is arranged in the oven frame 35 below the housing 30 on the lower belt section of the circumferential path of the baking belt 27. The belt preheating device 34 extends along the lower run 27b of the baking belt 27. It has a support frame 37 supported on the bottom 36, which supports the inductor 33, which is fastened to the support frame 37 so as to be electrically insulated. The inductor 33 is arranged adjacent to the lower run 27b of the baking belt 27. The lower run 27b of the revolving baking belt 27 passes the extensive magnetic field generated by the inductor 33 and is thereby heated inductively to a high belt temperature in a contactless manner by means of this magnetic field.
The baking belt 39 is embodied as a continuous susceptor belt, which can be heated inductively to high belt temperatures in a contactless manner by means of an electrical induction heater in a contactless manner and which can be heated inductively to high belt temperatures.
The baking oven 38 is equipped with an inductive belt preheater, which is embodied as an electrical induction heater. The alternating current generator of the induction heater is connected to an extensive inductor 43 via current lines. The inductor 43 is arranged in an upper belt preheating device 44, which is arranged in the input station 41 of the baking oven 38 adjacent to the upper run 39a of the baking belt 39. The upper run 39a of the baking belt 39 passes the extensive magnetic field generated by the inductor 43 and is thereby heated inductively to a high belt temperature in a contactless manner by means of this magnetic field.
The baking belt 46 is embodied as a continuous susceptor belt, which can be heated inductively to high belt temperatures in a contactless manner by means of an electrical induction heater.
The baking oven 45 is equipped with an inductive belt preheater, which is embodied as an electrical induction heater. The alternating current generator of the induction heater is connected via current lines to an extensive inductor 50, which is arranged in a lower belt preheating device 51, which is arranged between the front belt deflecting station 47 and the housing 49. The revolving baking belt 46 passes the lower belt preheating device 51 with its lower run 46b and is heated inductively at that location to a high belt temperature in a contactless manner by means of the extensive magnetic field generated by the inductor 50.
Number | Date | Country | Kind |
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A 667/2011 | May 2011 | AT | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/EP2012/058137 | 5/3/2012 | WO | 00 | 6/23/2014 |