FACILITY FOR THAWING OR TEMPERING FROZEN FOOD PRODUCTS

Abstract

A facility for thawing or tempering frozen food products, including: a chamber for receiving the products to be thawed or tempered, a fan for establishing a forced air flow in the chamber at a speed greater than or equal to 5 ms.sup.1, a heater for heating the products present in the chamber, including at least one of a device for injecting or creating steam in the chamber, a device for spraying, showering or misting hot water or water at room temperature, a device for mixing air on a hot heat exchanger or a heating resistor, and a high-frequency electromagnetic system, a device for cooling the air in the chamber including at least one of a device for injecting cold air via a dedicated inlet, a device for mixing air on a cold heat exchanger, and a device for misting, showering or spraying cold water in the chamber.

Claims

1-20. (canceled)

21. An installation for thawing or tempering frozen food products, including: a chamber for receiving the products to be thawed or tempered, ventilation means, for establishing a forced flow of air in the chamber at a speed greater than or equal to 5 ms.sup.1, means for heating the products present in the chamber, including at least one of the following: means for creation or injection of steam in(to) the chamber means for spraying, showering or misting hot water or water at room temperature, means for agitating air on a hot heat exchanger or an electric heating element, and a high-frequency, electromagnetic system. means for cooling the air in the chamber including means for misting, showering or spraying cold water in the chamber, means for regulating the temperature of the misted, showered or sprayed water to a setpoint value chosen as a function of time and/or a core temperature and/or a surface temperature of the products.

22. The installation as claimed in claim 21, including means for misting hot water or water at a temperature greater than or equal to 15 C. or at room temperature.

23. The installation as claimed in claim 21, including means for agitating air on a cold heat exchanger.

24. The installation as claimed in claim 21, including means for creation or injection of steam in(to) the chamber.

25. The installation as claimed in claim 21, the misted, showered or sprayed water being at a temperature below 6 C.

26. The installation as claimed in claim 21, the forced flow of air being effected in a closed circuit.

27. The installation as claimed in claim 21, including a feed to be connected to a domestic cold water main and at least one refrigerator unit for cooling the water from the main to a required temperature before spraying it, delivering it by showering or misting.

28. The installation as claimed in claim 21, the ventilation means producing a forced flow of air at a speed greater than or equal to 5 ms.sup.1 at at least one location in the chamber.

29. The installation as claimed in claim 21, the ventilation means producing a forced flow of air at a speed greater than or equal to 10 ms.sup.1 at at least one location in the chamber.

30. The installation as claimed in claim 21, including a feed to be connected to a domestic hot water main or to a water heater external to the chamber so as to be able to deliver by showering, spraying or misting water at a temperature greater than 20 C. or 25 C. into the chamber.

31. A method of thawing or tempering frozen food products present in a chamber of a thawing or tempering installation, as defined in claim 21, including: subjecting the products to be thawed or tempered to a forced flow of air in the chamber and injection of steam and showering or spraying or misting with water, the water being delivered by showering, misted or sprayed at a controlled temperature.

32. The method of claim 31, the controlled temperature being below 10 C.

33. The method of claim 32, the controlled temperature being below 6 C.

34. The method as claimed in claim 31, in which the temperature of the water delivered by showering, misted or sprayed is varied as a function of time and/or a temperature measured at the surface of the products and/or a temperature measured at the core of the products.

35. The method as claimed in claim 31, the forced flow of air being effected at an air speed of at least 5 ms.sup.1 at at least one location in the chamber.

36. The method as claimed in claim 31, the forced flow of air being effected with an air speed of at least 10 ms.sup.1 at at least one location in the chamber.

37. The method as claimed in claim 31, the initial temperature of the frozen products being less than or equal to 30 C.

38. The method as claimed in claim 31, the injection of steam taking place during the showering, spraying or misting of water.

39. The method as claimed in claim 31, the forced flow of air being effected in accordance with at least two different air speed regimes as a function of the state of thawing or of tempering of the products.

40. The method as claimed in claim 31, the injection of steam being interrupted from a certain degree of thawing or of tempering of the products, whilst the showering, spraying or misting of water continues.

41. The method as claimed in claim 40, the temperature of the water misted or sprayed after stopping the injection of steam being less than or equal to 5 C.

42. The method as claimed in claim 31, the temperature of the water delivered by showering, misted or sprayed varying from T.sub.1 at the beginning of the thawing or tempering process to T.sub.2 at the end of said process, with T.sub.2<T.sub.1.

Description

[0062] The invention will be better understood after reading the following description of one nonlimiting embodiment thereof and examining the appended drawing, in which:

[0063] FIG. 1 is a perspective view of one example of a thawing or tempering installation according to the invention, and

[0064] FIG. 2 represents a detail from FIG. 1.

[0065] The thawing or tempering installation 10 according to the invention represented in FIGS. 1 and 2 includes a frame 11, also termed a thawing or tempering cell, defining a chamber 12 into which the food products to be thawed or tempered may be introduced. The frame 11 is preferably made of stainless steel.

[0066] A door 13 makes possible access to the chamber 12 for putting in and removing products, which may be on a trolley.

[0067] The installation 10 may include, as shown, a refrigerator unit 15 that is for example fixed to the frame 11 on the side opposite the door 13.

[0068] The chamber 12 can communicate with the outside via an air inlet 21 and an air outlet 22 preferably situated on the top wall of the frame 11. The inlet and outlet may be equipped with check valves.

[0069] The air inlet and outlet valves are open if it is required that ambient air from the outside enters. That air may be that from a hot zone (25 C.) or from a cold zone (4 C.). Opening may also be the result of a request for relative humidity regulation.

[0070] The air inlet 21 may be provided with a temperature probe 23 making it possible to determine the temperature of the incoming air. The latter may be cooled air if the cell is placed in a cold room, the temperature of which is between 10 C. and +10 C. inclusive, for example.

[0071] The installation 10 includes manifolds 30 for diffusion of steam into the chamber 12. These manifolds 30 communicate with steam inlets 31 connected to steam feed pipes, not represented. In the example shown, there are two manifolds 30 respectively situated in the vicinity of the left and right vertical walls of the frame 11. Each has a vertical section 30a that extends from the top wall 16 of the frame 11 over the greater part of the height of the chamber 12 and a horizontal section 30b near the floor 17 of the chamber 12.

[0072] The installation 10 may include, as shown, one or more heat exchangers 40 present in the chamber 12 to cool the air therein.

[0073] There are two exchangers 40, for example, as shown, present in the upper part of the chamber 12. They may be tubular water/air exchangers, the air from the chamber 12 circulating over the outside of the tubes 41, the latter being horizontal and having cold glycolated water passed through them. This water is for example cooled by the refrigerator unit 15 or comes from a cold glycolated water main of the plant.

[0074] The installation 10 includes nozzles 50 for misting water or an air/water mixture inside the chamber 12 in order to create a water mist therein. The particle size of the misted droplets is for example of the order of 1 to 60 m.

[0075] The nozzles 50 are preferably placed, as shown, below the exchangers 40, in the upper part of the chamber 12.

[0076] A fan 60, the motor of which is outside the chamber 12, creates a forced flow of air inside the chamber 12, with an air speed greater than 5 ms.sup.1, better still greater than 10 ms.sup.1.

[0077] The axis of the fan 60 may be vertical and situated between the exchangers 40.

[0078] The installation 10 may include a regulation central unit, also termed a programmable automatic controller, making it possible to control the operation of the various elements of the installation in order to subject the products to be thawed or tempered to conditions appropriate for warming them.

[0079] Various temperature probes are connected to this central unit and regulation is notably effected as a function of the measured temperatures.

[0080] The installation 10 may therefore include a plurality of probes, such as a core probe 81, a surface probe 82, a relative humidity probe 83 and an air temperature probe 84.

[0081] When the nozzles 50 receive compressed air and water, as shown, each air or water inlet may be equipped with a corresponding temperature probe 57, 58.

[0082] The temperature of the water feeding the nozzles and the air feeding the nozzle can therefore be controlled.

[0083] The relative humidity probe 83 can also serve to control misting in accordance with the programming of the central unit, the admission of steam and the entry of air, if for example there is a relative humidity setpoint. Regulation may operate on the relative humidity parameter as a function of temperature.

[0084] The steam that is diffused into the chamber 12 is at a temperature between 99 and 152 C. inclusive, for example.

[0085] The water that is misted via the nozzles 50 may be cold, lukewarm or hot water, its temperature preferably being controlled by the regulation central unit to remain at the required temperature, which may vary according to the stage of the thawing or tempering cycle. The misted water and/or the compressed air is or are cooled by the refrigerator unit 15 in the example shown.

[0086] To effect a thawing or tempering cycle, the food products present in the chamber 12, for example disposed on an appropriate trolley on multiple levels, are subjected for example to: [0087] diffusion of steam via the manifolds 30, [0088] forced flow generated by the fan 60, preferably at a speed of at least 5 ms.sup.1, [0089] misting of water via the nozzles 50.

[0090] The temperature of the misted water and the air that accompanies this misting may decrease as a function of the core temperature of the food products, from more than 10 C. at the beginning when the foods are the coldest to less than 6 C., for example when the injection of steam is interrupted at the end of the cycle.

[0091] The regulation central unit receives signals from the temperature probes and controls the solenoid valves for admitting steam into the manifolds 30 and spraying of water via the nozzles 50, the speed of the fan 60 and the temperature at which the water is misted via the nozzles, so as to optimize the thawing or tempering by aiming to increase the temperature of the food products as quickly as possible at the same time as maintaining their surface temperature at a sufficiently low value to degrade the appearance of the food as little as possible.

[0092] The invention is not limited to the example shown and it is possible for example to modify the geometry of the chamber 12, the number and location of the manifolds 30 for diffusion of steam, the number and location of the nozzles 50 or the exchangers 40, and the position of the fan 60.

[0093] In a variant, the misting nozzles are fed only with water under pressure. The misting nozzles may be replaced by spraying nozzles, which create a rain of droplets in the chamber rather than a mist.

[0094] The expression including a must be understood as being synonymous with comprising at least one unless otherwise indicated.