Oven with Smoke Supply

Abstract

The present invention relates to an oven comprising: a first and a second chamber and one heater per chamber to heat a gas which cooks a product, at least one gas circulation means, which establishes a gas circulation in one chamber, endless conveyor means for transporting products from an inlet through the chambers to the outlet, wherein the conveyor means are at least partially arranged in a helical path, separation means to separate the first and second chamber, wherein the conveyor means pass through the separation means, natural smoke gaseous supply which supplies gaseous smoke to at least one of the chambers, wherein the smoke supply is provided upstream from the circulation means.

Claims

1. Oven comprising: at least one chamber, the at least one chamber comprising at least one heater to heat a gas which cooks, dries and/or roasts a product, the at least one chamber comprising at least one gas circulation means, which establishes a gas circulation in the at least one chamber, endless conveyor means for transporting products from an inlet through the at least one chamber to an outlet of the at least one chamber, the endless conveyor means are at least partially arranged in a helical path, separation means to separate a first chamber and a second chamber, the endless conveyor means pass through the separation means, gaseous natural smoke supply, which supplies gaseous smoke to the at least one chamber, wherein the gaseous natural smoke supply is provided upstream from the at least one gas circulation means, wherein the oven comprises a collector/distributor, that collects and/or distributes the gas in the at least one chamber, wherein a pipe extends from the gaseous natural smoke supply into a drum and/or the collector/distributor and suppplies the gaseous smoke to an inside of the drum and/or the collector/distributor, and wherein a distance between an end of the pipe and an inlet of the at least one gas circulation means is adjustable.

2. Oven according to claim 1, wherein the oven comprises two chambers.

3. (canceled)

4. Oven according to claim 1, wherein the endless conveyor means are provided around the drum, the drum is hollow.

5. Oven according to claim 4, wherein the gaseous smoke is supplied to the inside of the drum.

6. Oven according to claim 1, wherein the gaseous smoke is supplied to the collector/distributor.

7. (canceled)

8. (canceled)

9. Oven according to claim 1, wherein the oven comprises a controllable smoke supply system, which comprises at least one adjustable valve and/or adjustable smoke supply means.

10. Oven according to claim 1, wherein the oven comprises an exhaust means to remove the gas from the oven, the gas is removed from the inlet and/or the outlet.

11. Oven according to claim 1, wherein the oven comprises means to supply air from an ambient, the ambient having a lower temperature and/or a lower dew-point and/or lower smoke content than the gas in the at least one chamber of the oven, to the oven, or to only one of the at least one chamber of the oven.

12. Oven according to claim 1, wherein the oven comprises two chambers, and a controlled leakage between the two chambers takes place.

13. Method to operate an oven comprising: at least one chamber and at least one heater per chamber to heat a gas which cooks, dries and/or roasts a product, at least one gas circulation means per chamber, which establishes a gas circulation in the at least one chamber, endless conveyor means for transporting products from an inlet through the at least one chamber to an outlet, the endless conveyor means are at least partially arranged in a helical path, separation means to separate a first chamber and a second chamber, the endless conveyor means pass through the separation means, gaseous natural smoke supply, which supplies gaseous smoke to the at least one chamber, wherein the gaseous smoke is supplied upstream from the at least one gas circulation means, wherein the oven comprises a collector/distributor, that collects and/or distributes circulating gas in the at least one chamber, wherein a pipe extends into a drum and/or a distributor, and wherein a distance between an end of the pipe and an inlet of the at least one gas circulation means is adjusted.

14. Method according to claim 13, wherein an exhaust means are provided to remove the gas from the oven, the gas is removed from the inlet and/or the outlet.

15. Method according to claim 13, wherein the oven comprises means to supply air from an ambient, the ambient has a lower temperature and/or a lower dew-point and/or lower smoke content than the gas in the at least one chamber of the oven, to the oven, or to only one of the at least one chamber of the oven.

16. Method according to claim 13, wherein a controlled leakage between two chambers takes place.

Description

[0046] Subsequently, the invention is now explained according to the attached figures. These explanations do not limit the scope of protection.

[0047] FIGS. 1-3 show an embodiment of the inventive oven.

[0048] FIG. 4 shows an embodiment in which the smoke-flow is directed in a certain way.

[0049] FIGS. 1-3 show the inventive oven. Here the oven 11 comprises a first chamber A and a second chamber B. The person skilled in the art understands, that one chamber A, B may be sufficient. The chambers are divided by a separation means 7, for example a metal wall, preferable an insulated separation means, which is sealed against the housing of the oven. The oven comprises conveyor means 4, which transport the products to be cooked, dried and/or roasted through the oven. The conveyor means 4 are here utilized by a helical transport belt in each chamber A, B, which are connected by a straight part in the vicinity of the partition 7. In case that only one chamber is provided, this chamber preferably comprises a helical transport belt. A rotatable drum 12 is arranged in each of these chambers, around which the conveyor belt 4 is guided along the helical paths. The endless conveyor belt enters the oven 11 via the inlet 8 in the housing of the oven, preferably by a straight conveyor belt section and leaves the oven 11 via the outlet 9 in the housing, likewise preferably by means of a straight section. The two helical sections are preferably connected by the straight conveyor belt section, which lies here at the top. In case only one chamber is provided, the outlet 9 is in the same chamber as the inlet. The belt is preferably permeable to the process gas, e.g. air and steam and here smoke. The separation means 7 comprise a passage for the belt section between the two helical paths. The conveyor means are preferably operated continuously.

[0050] The gas in the oven, preferably a mixture of air and vapor, is heated by heating means, which are overall denoted by 2, which are here arranged in the top of the housing. There is preferably one heating means per chamber, which, more preferably can be controlled individually. These heating means 2 each comprise at least one here two recirculation means 3, here two fans. Here, there are two recirculation means per chamber A, B, even though the person skilled in the art understands that one recirculation means per chamber may be sufficient. The fluid flow rate of each circulation means and hence the degree of recirculation can be adjusted individually. The gas, is taken from, preferably sucked up, by the circulation means 3 from each chambers A, B and forced back into the same chamber, A, B from which it has been taken.

[0051] In the present case, the chamber also comprises gas collector-/distribution means 13, here a vertical pipe/channel with openings, which are distributed along the height of the pipe/channel, which collects the gas from each chamber and provides it to the circulation means 3. In the present case two collector-/distribution means 13 are provided. Each collector-/distribution means 13 is here connected to an individual recirculation means 3.

[0052] In the present case, the gas enters the hollow section of the gas collector-/distribution means 13 via conveyor means 4 which transport the products and which are provided around the in this embodiment closed rotatable drum 12. The recirculation pass is illustrated by arrows which are marked by the reference sign C. The gas here flows past the heating element(s) 2 and is then recycled into the respective chamber A, B via the drum 12 of each chamber. Prior to the reintroduction of the gas into the respective chamber, the gas flow may be distributed according to a desired pattern, particularly over the vertical height of the drum, by distribution means, which are provided in the drum, for example as openings, whose cross-section is preferably adjustable to influence the distribution of the gas. The person skilled in the art understands that the flow path of the gas indicated by arrow C can also be the other way round, i.e. the gas is pressed into the distributor 13 and distributed by the distributor and then flows through the chamber and is collected by the drum. The inlet of the circulation means 3 is then connected to the inner diameter of the drum.

[0053] In the two chambers A, B different dry-bulb temperature- and/or humidity/dew-point temperature conditions can be set.

[0054] Inventively, the oven comprises a gaseous natural smoke supply 10, which provides smoke as a gas. The smoke is preferably produced by burning wood-chips or the like. Preferably no liquid smoke is used. The smoke is preferably produced by a smoke generator (not depicted) and is then, preferably immediately, used in the inventive oven. The smoke supply may comprise a compressor to increase the pressure of the gaseous natural smoke. The compressor is preferably controllable. The smoke supply 10 is connected to a pipe system, that directs smoke here to each chamber and in the present case at two different locations. The pipe system connects the hollow part of the gas collector-/distribution means 13 with the smoke supply and in the present case, each pipe extends into the hollow section of the gas collector-/distribution means 13. As can be particularly seen from FIG. 1, the length of the pipes and hence the distance E between downstream end of the pipe 5.1-5.4 and the inlet of the recirculation means is different. In case that at the suction side of the circulation means 3, there is a pressure level below ambient pressure, the driving force decreases with increasing distance E, and hence different amounts of smoke are sucked through each pipe. The pipe to the very right delivers least smoke, while the adjacent pipe delivers the largest amount of smoke. The two pipes to the left deliver the same amount of smoke, because their distance E is the same, assuming that the two circulation means 3 operate under the same condition.

[0055] Additionally, or alternatively, one or more valves 6.1-6.4 may be provided to manually or automatically adjust the amount of smoke provided through each pipe. Further additionally or alternatively, the pressure at which the natural gaseous smoke is provided can be controlled in order to modify the allover supply and/or the distribution to the pipe 5.1-5.4. In an alternative embodiment the amount of smoke can be reduced by connecting reducing means such as a cone element to the smoke pipes 5.1-5.4, preferably at the top end of the pipe there where the gaseous smoke exits the smoke pipes.

[0056] In the embodiment according to FIG. 3, there is only one central valve 6.7, which controls the overall supply of smoke to the oven.

[0057] The smoke is provided together with the recirculating gas to the recirculation means, compressed by the recirculation means 3 and then heated by the heat exchanger 2 and is then recirculated back into the chamber from which it has been taken. Due to the supply of the smoke on the inlet side of the recirculation means, the newly added smoke is mixed well with the recirculating gas stream and no concentrated smoke can get to the ambient, because the pressure level at the upstream end of the circulation means is preferably lower than the ambient, as long as the recirculation means 3 operates.

[0058] The flow pattern of the recirculating stream and hence the smoke is depicted in FIGS. 1 and 4. It can be seen that the flow is directed essentially horizontally past the different levels of the helical path. At the present example, the flow is directed from the outside of the helical to the inside. Since, as depicted in FIG. 4, the products 27 for instance meat products turn on the helical path relative to the flow direction of the smoke, the degree of smoking of all parts of the products is equalized.

[0059] FIG. 5 depicts an embodiment wherein smoke generator 14 is preferably not be located within production room 17 which comprises oven 11 but preferably in a separated production room 14. This can prevent that combustion gases generated by smoldering wood chips within the smoke generator, enter the production room 17.

[0060] In a preferred embodiment smoke generator 14 sensing means 22 such as pressure means are provided in the smoke supply line 25 from the smoke generator to the oven. In case pressure means are provided, for example a pressure drop can be measured over the supply line within the smoke generator and/or over the supply line from the smoke generator to the oven and/or at other locations within the smoke supply to the oven. Depending on the pressure drop the smoke supply can be reduced and in case a predetermined pressure drop will be exceeded combustion within the smoke generator can be stopped by, for example, stopping the oxygen/fresh air supply to the combustion chamber and/or by extinguishing the combustion chamber.

[0061] In another or additional preferred embodiment the ratio fresh air/combustion gases supplied to the oven 11 will be directly measured and/or determined by measuring the gas composition, this ratio is preferably at least 20:1. Depending on the ratio of fresh air supply within smoke generator 14 and/or the combustion, the process can be controlled such that the ratio is maintained within a correct range. In case a predetermined ratio range is exceeded, such that, for example, too much combustion gas is within the smoke gases, for instance due to malfunction of the fresh air supply within the smoke generator, the smoke generator can be stopped. The supply of fresh air can be measured and/or determined preferably with means 21 such as pressure sensing means and/or volume flow measurement. Further detection means which can be used are carbon monoxide or carbon dioxide detectors. In case a predetermined value is exceeded, for instance the volume proportion of carbon monoxide exceeds a predetermined value the smoke generator can be stopped.

[0062] In a further preferred embodiment the supply of fresh air to/within the smoke generator will be such that air is supplied via one single air supply and will internally be divided by dividing means to respectively the combustion chamber and a distribution chamber. In the distribution chamber the smoke gases from the combustion chamber and fresh air will be mixed to the preferred ratio of at least 20:1. From the distribution chamber the resulting gaseous smoke will be supplied to the oven.

[0063] In yet another preferred embodiment the operation of fans 20.1 and 20.2 preferably positioned on the roof of the production facility can be monitored. Exhaust pipe 19.1 internally in communication with inlet 8 and exhaust pipe 19.2 internally in communication with outlet 9 of the oven can remove gases from oven 11, for example via suction by fans 20.1 respectively 20.2. In case fans 20.1 and 20.2 don't operate property gases from the oven will flow via inlet 8 and/or outlet 9 out of the oven into the production room 17. A proper operation of the fans can be determined by measuring the number of revolutions of the fans for instance with a pulse counter. In case the measured number of revolutions differentiates from a predetermined value the control unit will switch off the smoke generator.

[0064] In another preferred embodiment the gas flow within exhaust pipes 19.1 and 19.2 can be measured with sensing means 23.1 respectively 23.2. In case fans 20.1 and 20.2 operate property and/or valve means 26.1 and 26.2 are sufficiently opened, the control unit can, in case the volumetric flow rate and/or pressure drop is below a predetermined value, conclude that leakage of gases from the oven, for example, via inlet 8 and/or outlet 9 and/or eventually supplied fresh air intake openings of the oven to production room 17 occurs. In this case the smoke generator can be switched off.

[0065] In a further preferred embodiment sensing means 24.1 can be located within/outside inlet 8 and/or sensing means 24.2 located within/outside outlet 9 of oven 11 such as means to detect the ratio combustion gases/fresh air will be applied. Other detection means which can be used are carbon monoxide or carbon dioxide detectors. In case the composition of gases is not according a predetermined value range the smoke generator should be controlled such that the gas composition should be corrected and/or the smoke generator should be switched off.

[0066] In another preferred embodiment sensing means 24.1 and/or 24.2 are able to detect leakage of gases out of inlet 8 and/or outlet 9. In case one or more of the sensing means, for instance a temperature sensor and/or a pressure sensor senses that a predetermined value is exceeded, valves 26.1 and 26.1 within the exhaust pipes can be opened and/or further opened in order to control the exhaust of gases until the sensed value is within a predetermined value range. In case the predetermined value range exceeds the smoke generator is switched off. The temperatures during the smoking process within the respective chamber can be preferably in the range of 60 C.-120 C., much lower than in a regularly oven environment.

[0067] The operation of fans 3 within the oven can be monitored by sensing means such as the fan motor revolution. In case gas density (which can be part of the measurements) within the oven increases and the ratio fresh air/combustion gases exceeds a predetermined value, explosion danger can increase and the smoke generator is preferably switched off. In another embodiment the CIP (Clean In Place) supply line and connected CIP nozzles integrated in oven 11 to clean the oven can be used in an undesired situation such as in case fire is detected. Detection can be done by detection means such as a temperature sensor.

[0068] Sensing means 23 and/or 24 in combination with valve means 26 and fans 20 are further able to improve energy efficiency of the smoking process.

[0069] In case smoke, steam and/or ambient air is added to the oven, gas from one or both chambers can be removed from the oven via one or more exhaust means. The smoke, steam and/or ambient air addition to the oven can be utilized induce a desired leakage between the two chambers/zones of the oven.

REFERENCE SIGNS

[0070] 1 Hood [0071] 2 Heater, Heat exchanger [0072] 3 Circulation means, fan [0073] 4 Endless conveyor means, endless belt [0074] 5 Smoke pipe (5.1-5.4, 5.7) [0075] 6 Control valve (6.1-6.4, 6.7) [0076] 7 Separation means, Partition means [0077] 8 Inlet [0078] 9 Outlet [0079] 10 Natural smoke supply [0080] 11 Oven [0081] 12 Drum [0082] 13 Collector/Distributor [0083] 14 Smoke generator [0084] 15 Production room comprising smoke generator 14 [0085] 16 Air-conditioning in production room comprising smoke generator 14 [0086] 17 Production room comprising oven 11 [0087] 18 Air-conditioning in production room comprising oven 11 [0088] 19 Exhaust pipe [0089] 20 Exhaust fan [0090] 21 Sensing means fresh air smoke generator 14 [0091] 22 Sensing means supply line smoke generator 14 [0092] 23 Sensing means exhaust gases oven 11 [0093] 24 Sensing means within/outside inlet oven and/or within/outside outlet oven 11 [0094] 25 Supply line smoke generator to oven 11 [0095] 26 Valve means in exhaust pipe 19 [0096] 27 Food product, Feed product, Meat product [0097] 28 [0098] A Zone 1, Chamber 1 [0099] B Zone 2, Chamber 2 [0100] C Gas-circulation, air circulation [0101] D Upstream zone, Suction zone of the circulation means [0102] E Pipe distance, variable pipe distance