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Title:
CHAMBER AND A METHOD OF CHANGING TEMPERATURE OF FOOD PRODUCTS
Document Type and Number:
WIPO Patent Application WO/2021/064288
Kind Code:
A1
Abstract:
The invention relates to a chamber (1) and method for changing temperature of food products. The chamber (1) comprises a food compartment (6) having an inlet (61) and an outlet (62) and at least one channel (60) extending between the inlet (61) and the outlet (62) allowing gas flow through the food compartment (6), a primary flow channel (20) extending between the inlet (61) and the outlet (62) of the food compartment (6); at least one temperature changing device (2) arranged to change temperature of gas coming from the food compartment (6), a recirculation flow channel (30) extending between the inlet (61) and the outlet (62) of the food compartment (6); and at least one recirculation fan (3) arranged to recirculate part of the gas flow coming through the food compartment (6).

Inventors:
BALABOLIN DMITRY (FI)
Application Number:
PCT/FI2020/050640
Publication Date:
April 08, 2021
Filing Date:
September 29, 2020
Export Citation:
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Assignee:
ALTERNATIVE ENERGY FUTURE OY (FI)
International Classes:
F25D17/06; A47F3/04; A47J39/00; F25D13/02; F25D13/06; F25D31/00
Domestic Patent References:
WO2009105074A12009-08-27
Foreign References:
FI104443B2000-01-31
US4354549A1982-10-19
Attorney, Agent or Firm:
PRIMROSE OY (FI)
Download PDF:
Claims:
CLAIMS

1. A chamber (1) for changing temperature of food products, said chamber (1) having walls (11) defining a chamber space (10) within the walls (11), c h a r a c t e r i z e d in that the chamber (1) comprising:

- a food compartment (6) for holding food products, said food compartment (6) having an inlet (61) and an outlet (62) and at least one channel (60) extending between the inlet (61) and the outlet (62) allowing gas flowthrough the food compartment (6),

- a primary flow channel (20) extending between the inlet (61) and the outlet (62) of the food compartment (6);

- at least one temperature changing device (2) arranged to change temperature of gas coming from the food compartment (6) and flowing through the temperature changing device (2), said at least one temperature changing device (2) being provided to the primary flow channel (20);

- a recirculation flow channel (30) extending between the inlet (61) and the outlet (62) of the food compartment (6); and

- at least one recirculation fan (3) arranged to recirculate part of the gas flow coming through the food compartment (6) from the outlet (62) of the gas channel (60) back to the inlet (61) of the gas channel (60), said at least one recirculation fan (3) being provided to the recirculation flow channel (30).

2. A chamber (1) according to claim 1, c h a r a c t e r i z e d in that the primary flow channel (20) is arranged to extend in the chamber space (10) outside of the food compartment (6) between the inlet (61) and the outlet (62) of the food compartment (6); or the recirculation flow channel (30) is arranged to extend in the chamber space (10) outside of the food compartment (6) between the inlet (61) and the outlet (62) of the food compartment (6); or the primary flow channel (20) and the recirculation flow channel (30) are arranged to extend in the chamber space (10) outside of the food compartment (6) between the inlet (61) and the outlet (62) of the food compartment (6).

3. A chamber (1) according to claim 1 or 2, c h a r a c t e r i z e d in that chamber (1) further comprises:

- at least one primary fan (4) arranged in connection with the food compartment (6), said at least one primary fan (4) is arranged to supply gas flow from the primary flow channel (20) and the recirculation flow channel (30) to the food compartment (6).

4. A chamber (1) according to claim 3, characterized in that said at least one primary fan (4) being provided in the inlet (61) of the food compartment (6); or said at least one primary fan (4) being provided inside the food compartment (6).

5. A chamber (1) according to any previous claim, characterized in that the food compartment (6) comprises a movable or removable dividing structure (9) for providing the food compartment (6) with multiple channels (60) through the food compartment (6).

6. A chamber (1) according to any previous claim, characterized in that the chamber (1) further comprises:

- a partitioning structure (5) arranged to divide at least part of the chamber space (11) into the primary flow channel (20) and the recirculation channel (30).

7. A chamber (1) according to claim 6, characterized in that the partitioning structure (5) is a tube forming the primary flow channel (20); or the partitioning structure (5) is a tube forming the recirculation flow channel (30); or the partitioning structure (5 is a tube forming the primary flow channel (20) and the recirculation flow channel (30); or the partitioning structure (5) is a wall structure having one or more walls. 8. A chamber (1) according to claim 6 or 7, characterized in that the partitioning structure (5) is provided in an upper side of the food compartment between a top wall (11) of the chamber (1) and the food compartment (6); or the partitioning structure (5) is provided between a side wall (11) of the chamber (1) and the food compartment (6). 9. A chamber (1) according to any previous claim, characterized in that the chamber (1) further comprises:

- at least one food support structure (7) provided in the food compartment (6).

10. A chamber (1) according to claim 9, characterized in that the at least one food support structure (7) being a food trolley removably arranged in the food compartment (6); or a hanger arrangement provided in an upper part of the food compartment (6); or a shelf structure provided in the food compartment (6).

11. A chamber (1) according to any previous claim, characterized in that the walls (11) comprising thermal insulation; or the chamber (1) being a thermal insulation chamber.

12. Method of changing temperature of food products provided in a food compartment (6) having an inlet (61) and an outlet (62) such that the food compartment (6) extending between the inlet (61) and the outlet (62), the food compartment (6) is arranged inside a chamber (1), which the chamber (1) having walls (11) defining a chamber space (10) inside the chamber (1), characterized in that the method comprises the steps of: a) supplying a gas flow (600) to the food compartment (6) via the inlet (61) of the food compartment (6) for changing temperature of the food products in the food compartment (6); b) discharging the gas flow (600) as a discharged gas flow (601) from the food compartment (6) via the outlet (62) of the food compartment (6); c) circulating a first portion (602) of the discharged gas flow (601) from the outlet (62) of the food compartment (6) back to the inlet (61) of the food compartment (6) via a primary flow channel (20) provided with a temperature changing device (2); d) supplying the first portion (602) of the discharged gas flow (601) through a temperature changing device (2) and providing a temperature changed gas flow (604) by changing temperature of the first portion (602) of the discharged gas flow (601) in the temperature changing device (2); e) recirculating a second portion (603) of the discharged gas flow (601) as a recirculated gas flow (605) from the outlet (62) of the food compartment (6) back to the inlet (61) of the food compartment (6) via a recirculation flow channel (30) provided inside the chamber (1) and outside of the food compartment (6); and f) combining the first portion (602) and the second portion (603) of the discharged gas flow (601) for providing the gas flow (600) and for supplying the gas flow (600) to the food compartment (6) via the inlet (61) of the food compartment (6).

13. Method according to claim 12, characterized in that the step c) further comprises circulating the first portion (602) of the discharged gas flow (600) via the primary flow channel (20) provided inside the chamber (1) and outside of the food compartment (6).

14. Method according to claim 12 or 13, c h a r a c t e r i z e d in that the step f) further comprises supplying the gas flow (600) to the food compartment (6) through at least one primary fan (4) provided to the inlet (61) of the food compartment (6).

15. Method according to any of claims 12-14, characterized in that the step e) further comprises operating a recirculation fan (3) provided to a recirculation flow channel (30) for recirculating the second portion (603) of the discharged gas flow (601).

16. Method according to any of claims 12-15, characterized in that the step d) further comprises operating the temperature changing device (2) provided to the primary flow channel (20).

Description:
CHAMBER AND A METHOD OF CHANGING TEMPERATURE OF FOOD PRODUCTS

FIELD OF THE INVENTION

The present invention relates to a chamber for changing temperature of food products, and more particularly to a chamber as defined in the preamble of the independent claim 1.

The present invention also relates to a method of changing temperature of food products, and more particularly to a method as defined in the preamble of the independent claim 12.

BACKGROUND OF THE INVENTION

In order to maintain properties of food products unchanged when they are stored the temperature of stored food products need to be maintained in certain values and this is achieved with cooled air surrounding the food products. Prior art cooling chambers for keeping food products cool have normally an insulation and a cooling unit provided in the cooling chamber such that all air provided in the cooling chamber is circulated through the cooling unit. Cooling of the air in the cooling chamber is very energy consuming.

BRIEF DESCRIPTION OF THE INVENTION

An object of the present invention is to provide an energy efficient way of changing temperature of food products such that food products can be cooled or heated such that the food properties remain mostly unchanged.

The objects of the invention are achieved by a chamber and a method for changing temperature of food products which are characterized by what is stated in the independent claims. The preferred embodiments of the invention are disclosed in the dependent claims.

The invention is based on the idea of separating gas flow coming from the food products and circulating part of the gas flow to a temperature changing device for changing the temperature of the gas flow and circulating part of the gas flow straight back to the food compartment. The temperature changing device can be either a freezing device for cooling the gas and thereby cooling the food products provided in the food compartment or a heating device for heating the gas and thereby heating the food products provided in the food compartment. In the case of heating the food products provided in the food compartment can be either frozen food products that will be thawed or warm food products maintaining their temperature or food products that will be heated. The gas is preferably air. In other words, in the most preferable embodiments of the invention is air circulated in the chamber.

According to the invention the chamber for changing temperature of food products have walls defining a chamber space within the walls and comprises a food compartment for holding food products, a primary flow channel extending between the inlet and the outlet of the food compartment, at least one temperature changing device arranged to change temperature of gas coming from the food compartment and flowing through the temperature changing device, a recirculation flow channel extending between the inlet and the outlet of the food compartment and at least one recirculation fan arranged to recirculate part of the gas flow coming through the food compartment. The food compartment having an inlet and an outlet and at least one channel extending between the inlet and the outlet allowing gas flow through the food compartment. Said at least one temperature changing device is provided to the primary flow channel and said at least one recirculation fan arranged to recirculate part of the gas flow coming through the food support compartment from the outlet of the gas channel back to the inlet of the gas channel is provided to the recirculation flow channel.

The chamber according to the invention is for example a room which is provided with a separate food compartment into which for example food trolleys can be placed. A separate food compartment in the context of this application means that the food compartment is separated from the rest of the chamber by a wall or other division structure, but the food compartment has an inlet and an outlet through which the gas flow enters and leaves the food compartment and through which food is placed or removed from the food compartment. Therefore, the inlet and the outlet of the food compartment is arranged to form a flow path for the gas flow but also a loading and unloading path for the food product. The channel extending between the inlet and the outlet of the food compartment is a channel for the gas flow to flow through the food compartment but also a channel for supporting, i.e. holding, the food product in the food compartment such that the gas flow is arranged to go through the food product provided in the channel. In other words, the chamber comprises a food compartment for food products having at least one channel through the food compartment such that the channel comprises an inlet and an outlet. In other words, the food compartment having a flow through structure between the inlet and the outlet. The channel can be a space between two shelves in a trolley or the channel can be the whole food compartment space having an opening, i.e. an inlet in one end and another opening, i.e. an outlet in the other end. This can be for example in embodiments in which the food compartment is provided with hangers for meat and a gas flow is arranged to flow through the compartment such that it flows in from one end of the food compartment and flows out from the other end of the food compartment. The food compartment is provided within the chamber, i.e. inside the chamber walls and is a separate food compartment within the chamber. The chamber further comprises a primary flow channel and a recirculation flow channel such that said channels are separated from each other.

In an embodiment of the invention the primary flow channel is arranged to extend in the chamber space outside of the food compartment between the inlet and the outlet of the food compartment. Alternatively, or in addition the recirculation flow channel is arranged to extend in the chamber space outside of the food compartment between the inlet and the outlet of the food compartment. Alternatively, or in addition the primary flow channel and the recirculation flow channel are arranged to extend in the chamber space outside of the food compartment between the inlet and the outlet of the food compartment. In other words, the primary flow channel, the recirculation flow channel and the food compartment are separate from each other such that the primary flow channel and/or the recirculation flow channel are arranged separately from the food compartment, i.e. outside of the food compartment. In a preferred embodiment of the invention the recirculation flow channel is provided between the primary flow channel and the food compartment for example such that the recirculation flow channel is arranged next to the food compartment extending between the inlet and the outlet of the food compartment and the primary flow channel is arranged next to the recirculation flow channel and extending between the inlet and the outlet of the food compartment. The expression "extending between the inlet and the outlet of the food compartment" means that the primary flow channel and the recirculation flow channel have a length of at least the length of the gas channel of the food compartment, i.e. the inlet and the outlet of the food compartment are the inlet and the outlet of the gas channel extending through the food compartment. In other words, the recirculation flow channel is arranged next to the food compartment such that the gas flow flowing through the recirculation flow channel is arranged to flow a shorter route than the gas flow flowing through the primary flow channel. The expression "next to the food compartment" can be next either in a horizontal or vertical direction.

In another embodiment of the invention the chamber further comprises at least one primary fan arranged in connection with the food compartment. The at least one primary fan is arranged to supply gas flow from the primary flow channel and the recirculation flow channel to the food compartment. The at least one primary fan can be provided in the inlet of the food compartment, in connection with the inlet of the food compartment or alternatively inside the food compartment.

In another embodiment of the invention the food compartment comprises a movable or removable dividing structure for providing the food compartment with multiple channels through the food compartment. This means that for example the outlet of the food compartment may comprise a dividing structure which can be arranged such that gas coming through the flow channel in the food compartment is prevented from entering to the recirculation channel or that a flow path in part of the food compartment can be turned to flow from outlet to the inlet especially when the flow direction of the primary fan can be reversed. The movable or removable dividing structure can be for example an expandable wall which is air filled, e.g. inflatable. Another movable or removable dividing structure is a dummy trolley which can be arranged in the food compartment to prevent gas entering around the trolley. The dummy trolley is preferably not having gas channels for the gas to enter within the trolley. In other words, the food compartment may comprise dummy trolleys and/or food trolleys having curtains covering wheels under the trolleys.

In an embodiment of the invention the chamber further comprises a partitioning structure arranged to divide at least part of the chamber space into the primary flow channel and the recirculation channel. The partitioning structure can be for example a tube forming the primary flow channel or a tube forming the recirculation flow channel or a tube forming the primary flow channel and a tube forming the recirculation flow channel. Alternatively or in addition the partitioning structure can be a wall structure provided to separate the primary flow channel and the recirculation flow channel and the food compartment. Alternatively or in addition the partitioning structure is a wall structure having one or more walls.

In an embodiment of the invention the partitioning structure is provided in an upper side of the food compartment between a top wall of the chamber and the food compartment. Alternatively or in addition the partitioning structure is provided between the side wall of the chamber and the food compartment.

In an embodiment of the invention the chamber further comprises at least one food support structure provided in the food compartment. The food support structure is arranged to support food products inside the food compartment. The food support structure can be for example a food trolley removably arranged in the food compartment; or a hanger arrangement provided in an upper part of the food compartment for hanging food products such as meat; or a shelf structure provided in the food compartment. The food trolley as the food support structure can form multiple channels within the food compartment which the food compartment without the food trolley forms one channel. The channels formed by the trolley are formed by overlapping shelves of the trolley so that a channel is formed between two overlapping shelves, i.e. an upper surface of a lower shelf forms a bottom of a channel and a lower surface of an upper shelf forms a top of a channel.

The inlet of the food compartment is arranged to form an inlet for the gas flow to enter to the channel of the food compartment or to enter the multiple channels formed by the trolley arranged in the food compartment but also the inlet for the food trolley when the food trolley is introduced into the food compartment. The outlet of the food compartment is arranged to form an outlet for the gas flow to leave the channel of the food compartment of the leave the multiple channels formed by the trolley arranged in the food compartment as well as the outlet for the food trolley to be removed from the food compartment. However, the inlet of the food compartment may also serve for the purpose of removing the food trolley. The food compartment in the context of the application is arranged to hold food products. The food compartment has an inlet and an outlet and at least one channel extending between the inlet and the outlet and the food products are supported in the channel such that a gas flow flows from the inlet through the food products supported in the channel of the food compartment to the outlet.

The primary flow channel extending between the outlet of the food compartment and the inlet of the food compartment is arranged outside of the food compartment similarly as the recirculation flow channel.

In an embodiment of the invention the walls comprising thermal insulation; or the chamber itself is a thermal insulation chamber.

According to the method of changing temperature of food products provided in a food compartment, the food compartment having an inlet and an outlet such that the food compartment extending between the inlet and the outlet. The food compartment is arranged inside a chamber, which the chamber having walls defining a chamber space inside the chamber. The method comprises the steps of a) supplying a gas flow to the food compartment via the inlet of the food compartment for changing temperature of the food products in the food compartment; b) discharging the gas flow as a discharged gas flow from the food compartment via the outlet of the food compartment; c) circulating a first portion of the discharged gas flow from the outlet of the food compartment back to the inlet of the food compartment via a primary flow channel provided with a temperature changing device; d) supplying the first portion of the discharged gas flow through a temperature changing device and providing a temperature changed gas flow by changing temperature of the first portion of the discharged gas flow in the temperature changing device; e) recirculating a second portion of the discharged gas flow as a recirculated gas flow from the outlet of the food compartment back to the inlet of the food compartment via a recirculation flow channel provided inside the chamber and outside of the food compartment; and f) combining the first portion and the second portion of the discharged gas flow for providing the gas flow and for supplying the gas flow to the food compartment via the inlet of the food compartment.

In an embodiment of the method the step c) further comprises circulating the first portion of the discharged gas flow via the primary flow channel provided inside the chamber and outside of the food compartment.

In an embodiment of the method the step f) further comprises supplying the gas flow to the food compartment through at least one primary fan provided to the inlet of the food compartment.

In an embodiment of the invention the step e) further comprises operating a recirculation fan provided to a recirculation flow channel for recirculating the second portion of the discharged gas flow.

In an embodiment of the invention the step d) further comprises operating the temperature changing device provided to the primary flow channel.

The step a) further comprises supporting the food products in a channel extending between the inlet and the outlet in the food compartment and supplying the gas flow through food products provided in the channel of the food compartment.

An advantage of the invention is that the chamber is provided with separate flow paths for gas that is cooled or heated in the temperature changing device and for gas that is recirculated from the end of the food compartment to the beginning of the food compartment outside of the food compartment. The part of the discharged gas from the food compartment is recycled and flown back to the food compartment in a shorter path than the temperature-changed gas thereby providing energy efficiency because of the whole discharged gas will not be temperature-changed and yet the temperature energy from the through flow of the food compartment is maintained by combining the recycled gas with the temperature-changed gas before entering into the food compartment.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is described in detail by means of specific embodiments with reference to the enclosed drawings, in which

Figure 1 shows a first example of a chamber according to the invention; Figure 2 shows the chamber shown in figure 1 as a cut-out view as seen from side;

Figure 3 shows a second example of a chamber according to the invention;

Figure 4 shows a third example of a chamber according to the invention; Figure 5 shows a fourth example of a chamber according to the invention;

Figure 6 shows the chamber shown in figure 5 as a cut-out view as seen from side;

Figure 7 shows a fifth example of a chamber according to the invention as seen from side;

Figure 8 shows a sixth example of a chamber according to the invention; Figure 9 shows the chamber shown in figure 8 as a cut-out view;

Figure 10 shows a seventh example of a chamber according to the invention; and

Figure 11 shows a further example of a chamber according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

Figure 1 shows a first example of a chamber according to the invention in which the chamber 1 is seen from above showing walls 11 surrounding the chamber space 10. The food compartment 6 comprises at least one gas channel 60 through the food compartment 6. The gas channel 60 extends between an inlet 61 and an outlet 62 such that the inlet 61 is provided with at least one primary fan 4 and in this example two primary fans 4. The food compartment 6 may be provided with food support structures which in this example are three trolleys (seen in figure 2) such that the gas channel 60 through the food compartment 6 is divided into multiple gas channels 60 within the trolley. The area between the inlet 61 and the trolleys is forming a single gas channel 60. The outlet 62 of the food compartment is formed by the trolleys. The primary fans 4 supply a gas flow 600 through the food compartment 6 such that a discharged gas flow 601 is discharged from the outlet 62 of the food compartment 6. The chamber 1 further comprises a primary flow channel 20 and a recirculation flow channel 30. Both the primary flow channel 20 and the recirculation flow channel 30 extend between the inlet 61 of the food compartment and the outlet 62 of the food compartment 6 such that the discharged gas flow 601 is circulated from the outlet 62 of the food compartment 6 to the primary flow channel 20 and to the recirculation flow channel 30 such that a first portion of the discharged gas flow 601 is circulated to the primary flow channel 20 and a second portion of the discharge gas flow 601 is circulated to the recirculation flow channel 30. After flowing through the channels 20, 30 the temperature-changed gas flow 604 which is temperature-changed in a temperature changing device 2 and the recirculated gas flow 605 flown through a recirculation fan 3 are combined as the gas flow 600 flowing to the food compartment through the inlet 61 of the food compartment 6 and through the primary fans 4. The primary flow channel 20 and the recirculation flow channel are separated from each other and from the food compartment 6 by a partitioning structure 5 which can be a wall structure, a tube structure or other separation structure.

Figure 2 shows the chamber 1 shown in figure 1 as a cut-out view A-A and as a view seen from side in which food support structures 7 are trolleys provided in the food compartment 6. This figure shows that the partitioning structure 5 separating the primary flow channel 20, the recirculation flow channel 30 and the food compartment 6 from each other is a wall structure. In this example the primary flow channel 20 comprises two temperature changing devices 2 such as freezing devices or heating devices and the recirculation flow channel 30 comprises two primary fans 3 such as pumps which recirculate the recirculation flow. The gas channel 60 through the food compartment 6 is formed by the multiple gas channels through the trolley shelves.

Figure 3 shows a second example of a chamber according to the invention in which the partitioning structure 5 comprises a flow guide 8 for guiding the recirculated gas flow 605 from the recirculating flow channel 30 toward the inlet 61 of the food compartment 6. Also the corners of the chamber are provided with flow guides 8 for guiding the gas flows within the chamber. The flow guides 8 provided at the corners of the chamber can be formed of sheet material such as sheet of metal or plastic. The corners having flow guides 8 are preferably formed such that the radius R for the curvature of the flow guide 8 is same or bigger than the width w of the primary flow channel 20. Rounded corners, i.e. corners having a flow guide, can be applied to any of the embodiments of the invention. Otherwise the features in this example are similar to those shown in figure 1.

Figure 4 shows a third example of a chamber according to the invention in which the walls 11 of the chamber 1 are provided with flow guides 8 such that all the corners of the chamber 8 are formed as rounded. However, the invention is not limited to the embodiment in which all the corners are formed as rounded but only one or two can be rounded. In the example shown in figure 4 also the partitioning structure 5 is also provided with a flow guide 8.

Figure 5 shows a fourth example of a chamber according to the invention in which the temperature changing device 2 and the primary fan 4 are provided in the same flow direction on opposite sides of the food compartment 6 such that the discharged gas flow 601 coming from the outlet 62 of the food compartment 6 continues its flow path to the temperature changing device 2. The recirculation fan 3 is provided in the recirculation flow channel 30 and is arranged to recirculate part of the discharged gas flow 601. The partitioning structure 5 is arranged to extend between the primary flow channel 20 and the recirculation flow channel 30 such that the channels 20, 30 extend as circular channels around the food compartment 6. The recirculation flow channel 30 is preferably as shown in this example provided in the vicinity of the food compartment and extending close to the food compartment 6 whereas the primary flow channel 20 is arranged to extend on the outer perimeter further from the food compartment 6 such that the recirculation flow channel 30 is provided between the primary flow channel 20 and the food compartment 6. The primary flow channel 20 and the recirculation flow channel 30 are separated from each other by the partitioning structure 5 extending in more than one direction in the chamber 1 and in this example in two directions forming an outer flow channel and an inner flow channel around the food compartment 6 such that the primary flow channel 20 forms the outer flow channel and the recirculation flow channel 30 forms the inner flow channel. Figure 6 shows the chamber shown in figure 5 as a cut-out view B-B as seen from side such that the figure shows the food support structure 7 is three food trolleys provided in the food compartment 6 and forming multiple flow channels 60 through the food compartment 6. The recirculation flow channel 30 is provided with two recirculation fans 3 and the partitioning structure 5 is provided as a wall structure extending between the bottom and top walls of the chamber 1.

The food compartment 6 also comprises flow blockers 80 for preventing gas entering into other places than the gas channels 60 extending through the food compartment 6. The flow blockers 80 are for example provided as curtains for the wheels under a food trolley or dummy trolleys when larger areas are blocked. The flow blockers such as curtains covering the wheels of food trolley or dummy trolley are blocking the gas from entering areas that are not meant to form gas channels through the food compartment.

Figure 7 shows a fifth example of a chamber 1 according to the invention as seen from side in which the primary flow channel 20 and the recirculation flow channel 30 are arranged above the food compartment 6 such that the recirculation flow channel 30 is next to the food compartment 6 and the primary flow channel 20 is outmost from the food compartment 6. The primary fans 4 are provided in the inlet 61of the food compartment 6 for directing gas flow

600 through the gas channels 60 formed by food trolleys provided in the food compartment 6 and the discharged gas flow 601 exits the food compartment 6 through the outlet 61 of the gas channels 60. The discharged gas flow 601 is divided into two portions: the first portion 602 of the discharged gas flow 601 enters the primary flow channel 20 and the second portion 603 of the discharged gas glow

601 enters the recirculation flow channel 30. The recirculation fan 3 is arranged to draw the second portion 603 of the discharged gas flow 601 through the recirculation flow channel 30 as a recirculated gas flow 605 and the flow guide 8 arranged in connection with the partitioning structure 5 dividing the chamber space 11 into the primary flow channel 20 and the recirculation flow channel 30 is arranged to guide the recirculated gas flow 605 toward the inlet 61 of the food compartment 6. The temperature changing device 2 is arranged to draw the first portion 602 of the discharged gas flow 601 through the primary flow channel 20 and to change the temperature of the first portion 602 of the discharge gas flow 601 to form a temperature changed gas flow 604. At the inlet 61 of the food compartment 6 the recirculated gas flow 605 and the temperature changed gas flow 604 are combined to be the gas flow 600 to be supplied to the food compartment 6.

Figure 8 shows a sixth example of a chamber according to the invention in which the corners of the chamber 1 are rounded so as to guide the gas flows 600, 601, 602, 604 outermost from the food compartment 6 to move in a circular path and more efficiently. The recirculation flow channel 30 guides the recirculated gas flow 30 to follow a path which is closer to the food compartment 6. The flow guide 8 provided in the partitioning structure 5 is arranged to intensify the guidance towards the inlet 61 of the food compartment 6. Other features in the example shown in figure 8 are similar to those presented in connection with figure 7.

Figure 9 shows the chamber shown in figure 8 as a cut-out view along the line C-C. The food compartment 6 is in this example provided with two food trolleys as the food support structure 7. The food trolley shelves form the gas channels 60 through the food compartment 6. The temperature changing devices 2 and the recirculation fans 3 are provided above the food compartment 6 and separated from each other through partitioning structure 5.

Figure 10 shows a seventh example of a chamber 1 according to the invention in which the chamber 1 is provided with a partitioning structure 5 separating the recirculation flow channel 30 and the primary flow channel 20 from each other. The flow path of the recirculated gas flow 605 is forming a shell-like structure in which the food compartment 6 is an innermost part and the recirculation flow channel 30 forms a spiral around the food compartment 6. The temperature changed gas 604 is combined to the recirculated gas flow 605 at the inlet area of the food compartment 6 for recirculation. A dividing structure 9 is provided at the outlet 62 of the food compartment 6 for dividing the gas channels 60 such that the recirculation flow channel 30 is separated from the primary flow channel 20 from the outlet 62 of the food compartment 6 until the end of the recirculation flow channel 30 to more efficiently circulate the recirculated gas flow 605 combined with a portion of temperature changed gas whereas the temperature changed gas circulates its own path through the primary flow channel 20 in order to maintain the temperature of the temperature changed gas or to change the temperature of the gas more. The dividing structure 9 is preferably movable or expandable for changing the rotation of the gases within the chamber 1. Also the primary fans 4 in connection with the inlet 61 of the food compartment 6 may be reversible for changing the rotation of the gases.

Figure 11 shows a further example of a chamber according to the invention in which the recirculation flow channel 30 is formed within the food compartment with a dividing structure 9 arranged to extend through the food compartment 6 in the direction of gas channels 6. The dividing structure 9 is preferably movable such that the recirculation flow channel 30 can be adjusted. In this example one of the primary fans 4 work as a recirculation fan 3 such that the flow direction of the primary fan 4 is reversed from that of the other primary fans 4.

The invention has been described above with reference to the examples shown in the figures. However, the invention is in no way restricted to the above examples but may vary within the scope of the claims.