METHOD AND ARRANGEMENT FOR GENERATING SMOKE FROM LIQUID SMOKE CONDENSATES

Technical Field of the Invention

The present invention relates to a method and an arrangement for generating smoke from a liquid smoke condensate.

Technical Background

It is known to use liquid smoke condensates for preparation of food. Liquid smoke condensates are produced using smoke from for instance wood combustion and they are available in different concentrations and flavours. The composition of the regenerated smoke is an important aspect in order to achieve a good smoking result, i.e. duplicating the traditional smoking process to achieve similar taste and colour.

US 3,861 ,292 discloses a liquid smoke regenerator for use in connection with a smoke housing, in which used smoke is recycled. Heating is in this case essential in order to raise the temperature of the steam of air and liquid smoke particles to a temperature above the boiling point temperature, for the liquid smoke to cause reconversation of the elements to their corresponding vapour form of water and smoke. Use of a recycled blend from a smoke housing may impair the conditions for generation of a high quality smoke cloud since the blend contains a high level of moistness.

Summary of the Invention

It is an object of the present invention to provide an improved solution that alleviates the mentioned drawbacks with present methods for generating smoke from liquid smoke condensates.

A further object of the present invention is to provide an arrangement for preparation of food which reduces at least some of the above problems.

A further object is to provide an improved method for generating smoke from a liquid smoke condensate, for preparing of food inside a smoke housing, as regards quality of the generated smoke received in the smoke housing.

A further object is to provide an arrangement for generating smoke from a liquid smoke condensate, for preparing of food inside a smoke

housing, as regards quality of the generated smoke received in the smoke housing.

The above-mentioned objects are achieved by a method for generating smoke from a liquid smoke condensate for preparing of food inside a smoke housing, said smoke being generated in a first smoke generation housing having a channel to said smoke housing, comprising the steps of: introducing pressurized liquid smoke and air through a first nozzle into said first smoke generation housing for generating smoke; introducing ambient air into said first smoke generation housing through an inlet that is positioned at a lateral distance to a main flow direction of said first nozzle; heating of flowing medium inside said first smoke generation housing; introducing the generated smoke into said smoke housing.

Thus, a high quality smoke cloud is generated in a smoke generation housing and received in a smoke housing. The generated smoke can be used in a continuous smoking system since the smoke generation housing is flow- connected to the smoke housing and thus, there is no need to stop the smoke housing ventilation during supply of smoke to a smoke housing. Thus, the smoke generated can be used for a variety of smoking processes, such as cold, hot or steam smoking. By heating the flowing medium, condensation of the generated smoke inside the smoke generation housing is reduced. Also, condensation of the generated smoke flowing to a smoke housing is reduced. Thus, a method that effectively use the liquid smoke condensate is provided since condensation of smoke is reduced. Since condensation of smoke is reduced clogging etc. may be reduced. Thus, efforts as regards maintenance and cleaning of the arrangement may be reduced. Thus, the working conditions for an operator may be improved and harmful releases to the external environmental may be avoided or reduced.

Thus, ambient air, which may have a relatively low level of moistness, can be introduced into the smoke generation housing. Since an ambient air inlet is positioned at a lateral distance from the nozzle the smoke generation is not disturbed by the inflowing air. Thus, a stable high quality smoke cloud is generated inside the smoke generation housing and introduced into the smoke housing for preparation of food. In one aspect of the present invention, an arrangement for preparation of food inside a smoke housing according to the introduction is further characterised in that said first smoke generation housing comprises a first

nozzle for introducing of pressurized liquid smoke and air into said first smoke generation housing and a first ambient air inlet positioned at a lateral distance to a main flow direction of said first nozzle.

Thus, ambient air, which may have a relatively low level of moistness, can be introduced into the smoke generation housing. Since an ambient air inlet is positioned at a lateral distance from the nozzle the smoke generation is not disturbed by the inflowing air. Thus, a stable high quality smoke cloud is generated inside the smoke generation housing and introduced into the smoke housing for preparation of food. Preferably, said first smoke generation housing further comprises a heat source for heating of flowing medium inside said first smoke generation housing. By heating the flowing medium, condensation of the generated smoke inside the smoke generation housing is reduced. Also, condensation of the generated smoke flowing to a smoke housing is reduced. Thus, effective use of the liquid smoke condensate is provided since condensation of smoke is reduced. Since condensation of smoke is reduced clogging etc. may be reduced. Thus, efforts as regards maintenance and cleaning of the arrangement may be reduced. Thus, the working conditions for an operator may be improved and harmful releases to the external environmental may be avoided or reduced.

Preferably, said first smoke generation housing comprises a temperature sensor for sensing of the temperature inside the smoke generation housing. •

Preferably, said first smoke generation housing comprises a temperature regulator in order to regulate the temperature of flowing medium inside the smoke generation housing. Thus, a desired temperature of the flowing medium can be provided.

Brief Description of the drawings The present invention will now be described in more detail with the reference to the accompanying schematic drawings, which show a preferred embodiment in which:

Fig 1 shows a perspective view of an arrangement for preparation of food inside a smoke housing provided with a smoke generation housing according to an embodiment of the present invention.

Fig 2 shows a section view of an smoke generation housing according to an embodiment of the present invention.

Fig 3 shows a perspective view of the smoke generation housing shown in fig 2.

Detailed Description of a preferred embodiment Fig 1 shows an arrangement 1 for preparation of food, such as smoking of food, according to an embodiment of the present invention. The arrangement 1 comprises a smoke generation housing 2, a channel 3 and a smoke housing 4. The smoke generation housing 2 is flow-connected to the smoke housing 4 via the channel 3. The smoke generation housing 2 further comprises a container 5 for storage of liquid smoke condensate and a control system 6 for controling the generating of smoke inside the smoke generation housing 2. Compressed air is supplied to the smoke generation housing 2 through a pressure line (not shown). Smoke generated inside the smoke generation housing 2 is received in the smoke housing 4 through the channel 3. Flow of smoke and ambient air from the smoke generation housing 2 to the smoke housing 4 is achieved due to a lower pressure inside the smoke housing 4 compared to the pressure inside the smoke generation housing 2. The lower pressure inside the smoke housing 4 is generated by means of a ventilation system 7 connected to the smoke housing 4. Food to be prepared inside the smoke housing 4 is received through an opening 8 covered by a door 9. The smoke housing 4 has an outlet 10 to which a tube 11 is connected for outflow of used smoke. The smoke housing 4 further comprises a control unit 12 for controling the smoking process inside the smoke housing 4. Different types of smoking and cooking, such as cold, hot or steam smoking can be carried out using the arrangement 1.

Fig 2 shows a sectional view of a smoke generation housing 2 according to an embodiment of the present invention. In this embodiment the smoke generation housing 2 comprises two nozzles 13 for introducing of pressurized liquid smoke condensate and air into the smoke generation housing 2. Pressurized liquid and air is supplied to the nozzles via connections 14 and 15 respectively. The nozzles 13, which are combined fluid and air nozzles, are capable of generating a high quality smoke cloud 16. Thus, the nozzles 13 are adapted for high quality smoke generation from liquid smoke condensates. The smoke generation housing 2 comprises a first section 17 adapted for generating smoke. In the first section 17, the supplied liquid smoke condensate and air is transformed into a high quality smoke cloud 16. The length of said first section 17 is preferably larger than 0.5m,

more preferably larger than 0.7m and most preferably larger than 0.9m, originating from the first nozzle 13 and extending in a main flow direction of the nozzles 13. It is important that the flow from the nozzles 13 is not disturbed in the smoke generation section 17 in order to achieve a high quality smoke cloud 16. The smoke generation housing 2 further comprises a second section 18 and a third section 19, which have at least partly tapered cross sections, see fig 2. The sections 18 and 19 are provided for guiding of the generated smoke to an outlet 20. The outlet 20 is connectable to a smoke housing (not shown). In the second section 18, the flow direction of the generated smoke is changed, as indicated by the large arrows in fig 2. By changing the flow-direction a compact smoke generation housing 2 is achieved. In the passage through the sections 18 and 19 the flow rate of the flowing medium is increased due to the at least partly tapered cross-sections. The outlet 20 is connected to a channel (not shown) that is connected to a smoke housing (not shown). Alternatively, the outlet 20 may be directly connected to a smoke housing. About 1m after leaving the nozzles 13 a high quality smoke cloud is generated, i.e. smoke having a certain combination of gas phase and particle size.

Furthermore, the smoke generation housing 2 has an air inlet 21 , through which ambient air is received in the smoke generation housing 2. In this case the air inlet 21 is formed by two inlets 21' positioned at a lateral distance from the nozzles 13. The inlets 21' are flow-connected to an aperture 22 in the smoke generation housing 2. In this case the aperture 22 is formed by a number of apertures 22'. Before received in the smoke generation housing 2 the ambient air flowing through the apertures 22' is guided by a guiding plate 23, see figure 2. Thus, the ambient air enters the smoke generation space adjacent to the walls 24 forming part of the smoke generation housing 2. A heating source 25 is provided for heating of flowing medium inside the smoke generation housing 2. Figure 3 shows a perspective view of the described smoke generation housing 2. The arrow indicates where the generated smoke leaves the smoke generation housing 2 through the outlet 20 to be received in a smoke housing 4. An aperture 26 is covered by an openable maintenance cover 27. The openable maintenance cover 27 is provided for easy maintenance and cleaning of the smoke generation housing 2 and parts, such as the nozzles 13, mounted inside the smoke generation housing 2.

In the following, generating of smoke using an embodiment of the present invention is described. In generating a high quality smoke cloud, having a certain combination of gas phase and particle size, pressurized liquid smoke condensate and air are introduced into the smoke generation housing 2 trough the nozzles 13. The nozzles 13 are adapted to generate a high quality smoke. Thus, the mixture of liquid smoke and air supplied into the smoke generation housing through the nozzles 13 is transformed into smoke due to the geometry of the nozzles 13. The introduced pressurized liquid smoke condensate and air is transferred into a high quality smoke cloud approximately 1m, in the length extension of a main flow direction of the nozzles 13, after leaving the nozzles 13. A high quality smoke cloud 16 is thus generated.

Ambient air may be needed to provide the smoke housing with a desired flow rate. Depending on the required smoke flow rate more or less ambient air flows into the smoke generation housing 2 through the apertures 22'. The ambient air flowing through apertures 22' is guided by the guiding plate 23 and introduced into the smoke generation housing 2 adjacent to the walls 24 through the air inlets 21', as indicated by the small arrows in figure 2. The ambient air is introduced into the smoke generation housing through air inlets 21' located at a lateral distance from the nozzles 13 since it is important to not disturb the flow from the nozzles 13 to achieve a proper smoke generation.

The generated smoke cloud 16 and air inside the smoke generation housing 2 are heated by a heat source 25 in order to reduce condensation of the generated smoke inside the smoke generation housing 2 and condensation of the generated smoke during flow to a smoke housing 4. A temperature regulator provides that a certain temperature is ensured. Preferably, a temperature above 50° C is maintained, more preferably a temperature above 52° C is maintained and most preferably a temperature above 54° C is maintained. Thus, if the temperature of flowing medium inside the smoke generation housing 2 decreases below a certain value, heat is supplied in order to ensure that the temperature is above a certain value. By heating, also the smoke generation housing 2 itself is heated, which also reduces condensation of the generated smoke. It should be noted that the smoke generated from the nozzles 13 is already a stable smoke and does not need to be heated for smoke generation purposes.

The generating of smoke inside the smoke generation housing 2 is controlled by an electronic control system 6. Depending on the required flow rate into the smoke housing 4, smoke is generated continuously or stepwise. For instance, when a high flow rate is required, high quality smoke is continuously generated inside the smoke generation housing 2. On the other hand, when a low flow rate is required smoke is generated stepwise. The smoke generation housing 2 is capable of providing high quality smoke and air to the smoke housing at different flow rates. Typically, flow rates between 0.02-0.20 m ³ /s may be provided to a smoke housing 4. An electronic control system 6 controls the amount of smoke to be generated inside the smoke generation housing 2.

A high quality smoke cloud 16 generated inside the smoke generation housing 2 flows through the smoke generation housing 2 as indicated by the large arrows in figure 2 and is received in a smoke housing 4 via a channel 3. Depending on the required flow rate to the smoke housing more or less ambient air may also be received in the smoke housing 4 through the channel 3. The high quality smoke and air flow into the smoke housing 4 due to a lower pressure in the smoke housing 4 compared to the pressure inside the smoke generation housing 2. An electronic control system 6 ensures that optimal and precise pressure settings and flow rates are achieved. The control system 6 senses variations in air pressure and flow and automatically makes adjustments regarding the smoke generation inside the smoke generation housing 2 to provide a stable high quality smoke. Smoke generated in the smoke generation housing 2 can be used for cold, hot, or steam smoking.

It will be appreciated that the described embodiment of the invention can be modified and varied by a person skilled in the art without departing from the inventive concept defined in the claims.