MULTIPURPOSE BLAST CHILLER WITH REVERSIBLE CYCLE, WITH HIGH EFFICIENCY

Abstract

 Multipurpose blast chiller (10) for food, provided with a refrigeration circuit of reversible type (100a - 100b) with a differentiated path in the two circulation directions (115, 116), to carry out treatments in the cell (105) with temperature values between -40 °C and +110 °C, with high energy efficiency. A reverse cycle (100b) is provided for heating purposes, where the hot gas leaves the compressor (101) and proceeds with opposite flow (116) with respect to the refrigeration (100a, 115), to enter the evaporator (104) directly and heat the cell (105) without the help of electrical resistances (106) up to a temperature value equal to approximately + 60 °C. Before entering the condenser (102), in the reverse cycle, the gas is deviated to a secondary energy efficiency line (109), suitable for balancing the heat exchanges (102, 104) and protecting the motor (108) of the fans (107) from overheating, enveloping it with capillaries (110).

Description

[0001] The present invention relates to a multipurpose blast chiller for food with reversible cycle, with high efficiency.

Field of application

[0002] The invention relates to the industrial sector of refrigeration equipment for the processing of food, such as blast chillers for professional kitchens also called freezers. In particular, the proposed solution relates to multipurpose blast chillers, that is of the multifunction type, which are suitable for performing differentiated heat treatments in the same appliance both below and above 0 °C. By way of a preferential but not limiting example, reference is made to the known construction configuration of the multipurpose cabinet blast chillers with front closing door, which is widely used in the restaurant and catering professional field, where at least one evaporator and one electrical heating resistance are arranged inside a closed processing chamber, also called a cell. Very low temperature values are rapidly reached inside it for the purpose of preservation by blast chilling, generally equal to -40 °C, and also with values higher than 0 °C for heating purposes, for example + 60 °C, or + 70 °C in slow cooking treatments.

[0003] Modern blast chillers for food are refrigeration machines recently introduced and very widespread in professional practice, in various sectors of food production, being suitable for rapidly cooling fresh or just cooked food, in combination with strong ventilation, bringing it to an ideal temperature for preservation or postponed use. Such a treatment allows to preserve the flavor and organoleptic characteristics of the food, avoiding the formation of micro-crystals inside it, and it has a bacteriostatic function since it prevents bacterial proliferation in the short period of transition from the cooking temperature to a food safety temperature, for example -18 °C for freezing, allowing then a prolonged preservation of the food in conventional appliances.

[0004] Said blast chillers are widely used in restaurants, for example to preserve the healthiness of fish to be eaten raw or to prepare in advance certain foods to be served later, while maintaining the same quality as perceived when eating food freshly cooked. Furthermore, these appliances are used in delicatessens, bars, pastry shops, bakeries or icecream shops in order to safely store both fresh and freshly cooked products. In particular, the use of these blast chillers in professional activities related to the preparation of food has proved extremely effective in order to avoid the proliferation of microorganisms which are harmful to human health, so much that recent regulations have introduced the obligation to use them.

[0005] There has thus recently been a remarkable diffusion of the aforementioned rapid blast chillers, with particular interest for those of the multipurpose type, since they are appliances suitable for operating both in refrigeration and in heating, in food safety. It is indeed known to operators in the sector that a multipurpose blast chiller significantly facilitates daily professional activity and also allows to limit the space occupied and the overall costs. Consequently, there is a request for improving technical solutions, with respect to the conventional and known ones, with regard to the functioning of said multipurpose blast chillers in heating, the functioning in refrigeration being instead considered satisfactory. In particular, it is believed that the following can be improved:

• the system for defrosting the evaporator, as the known resistance or hot gas systems are not optimized in a multipurpose blast chiller;
• the maximum temperature limit which can be reached, as the limit which can be now reached is too low;
• the electrical energy consumption, this being excessively high;
• the overall efficiency of the system, as it can be largely optimized in a conventional multipurpose blast chiller.

[0006] To this aim, the technical solution proposed by the present invention intends to integrate a reversible refrigeration cycle into a multipurpose blast chiller in such a way as to fully and advantageously exploit, also in the heating phase, the thermal potential offered by the refrigeration circuit itself which operates in refrigeration. It is indeed known that a conventional refrigeration cycle based on the Carnot thermodynamic cycle has been applied for many years in industrial fields which are also very different from each other, both in refrigeration machines suitable for generating cold and in heat pumps suitable for generating heat. In summary, these machines have a closed circuit, also called a refrigeration circuit, in which a gas or gas mixture continuously circulates and continuously undergoes a change of state, under precise conditions of temperature and pressure, subtracting or releasing heat. To this aim, said circuit includes at least a compressor, a condenser, an expansion means and an evaporator, so that said gas each time condenses, releasing heat and then evaporates, removing it from the surrounding air. The condenser and the evaporator thus act as heat exchangers.

[0007] It is also known that in a refrigeration circuit, in order to generate cold, the gas has to flow in the conventional direction from the compressor towards the condenser, as happens in refrigerators and freezers, while in order to generate heat the gas follows a reverse cycle, with opposite flow, that is from the compressor towards the evaporator to return through the condenser, as happens for example in heat pumps for heating water. Furthermore, nowadays combined advantageous apparatuses are available, specifically developed for the building conditioning sector; they are configured as a conventional air conditioner consisting of an external unit including the condenser and an internal unit including the evaporator, in which the dual cooling - heating function is carried out simultaneously by the same refrigeration circuit; in such machines, said cycle is each time operated in direct way to cool, or in reverse way to heat the air.

[0008] More in detail of these combined air conditioners, when the circuit is operated in reverse cycle as a heat pump, the hot gas leaving the compressor is directly sent into the evaporator which is inside the building to condense releasing heat, while the condenser which is in the external unit consequently acts as a conventional evaporator. In this case the two exchangers are substantially equivalent for the purposes of heat exchange. By way of example, see the tables of the prior art (Figs. 1a and 1b), where a conventional refrigeration circuit is schematically represented of the type suitable for being integrated into a combined air conditioner, being respectively operating with direct cycle in cooling (Fig. 1a) or with reverse cycle in heating (Fig. 1b).

[0009] Furthermore, it is noted that in said air conditioners of combined type the cycle reversal is sometimes used temporarily also to defrost the evaporator and restore the correct heat exchange during cooling, briefly interrupting the conventional direct cycle.

[0010] Considering all the above, it has been noted that the aforementioned reversal of the cycle could be applicable, in principle, also to a multipurpose blast chiller for food in order to defrost the evaporator and to heat the food in the cell. However, there are various technical problems which prevent its application in a blast chiller according to the known and conventional art. Said industrial sector of air conditioning equipment has indeed very different purposes and operating modalities from the sector of equipment for professional catering.

[0011] Finally, it has been noted that multipurpose blast chillers of conventional type have a limited efficiency; they also allow a reduced range of treatments, in heating, compared to the modern needs of the professional catering sector.

Prior art

[0012] In order to determine the prior art relating to the proposed solution, where the hot gas is directly introduced into the cell of a blast chiller for heating, a conventional verification was carried out in the patent literature, examining public archives, which resulted in the identification of some prior art, including:

D1 JP2014119122 (Ishihara et al.)

D2 WO2018178405 (Albets Chico et al.)

D3 IT102019005938 (Favero)

[0013] D1 describes a refrigeration cycle appliance with a hot gas by-pass line for defrosting purposes, where the flow of said hot gas in the evaporator is regulated by means of a modulating valve on the basis of the overheat level and the saturation temperature exiting from the evaporator.

[0014] On the other hand, D2 proposes an adaptive control method for refrigeration systems, with the detection of the level of frost on the evaporator according to a calculation of the NTU rate, acronym for Number of Transfer Units, so as to define the most suitable moment for powering the defrosting electrical resistances, in combination with the fan of the evaporator itself.

[0015] D3 describes a blast chiller for food provided with an advanced evaporator defrosting system, with a hot gas by-pass line including a control valve, also known with the acronym HGDV, which is connected to a logic control unit provided with programs for automatically carrying out the opening and closing also according to the detection of multiple variable parameters, such as pressure and temperature.

[0016] In principle, it is thus reasonable to consider as known a system for defrosting in a blast chiller with interception of hot gas by means of a by-pass line provided with a flow regulation valve, or also a defrosting system with electrical resistances positioned in correspondence with the evaporator. In addition, systems for regulating the speed of the evaporator fans are known, also in combination with resistances, in order to slow down the formation of frost and ice as well as to improve the efficiency of the heat exchange. Finally, procedures are known for detecting and comparing the surface temperature of the evaporator with respect to other variable parameters of the circuit, to determine the presence of ice and activate a defrosting cycle.

[0017] Furthermore, the exclusive use of electric resistances in a blast chiller is known and conventional to heat food in the cell, deactivating the refrigeration circuit.

Drawbacks

[0018] A first disadvantage found in conventional and known solutions of multipurpose blast chillers for food concerns the fact that they involve the use of the refrigeration circuit only in refrigeration or, to a limited extent, to defrost the evaporator with partial deviation of the hot gas on a by-pass line dedicated to temporary defrost; and the thermal potential of the refrigeration circuit is not adequately exploited to heat the cell with said reversal of the refrigeration cycle, like a heat pump, in order to defrost the evaporator and thaw the food. More in detail, it has been experimentally found in the laboratory that in a conventional blast chiller operated with reverse cycle an excessive imbalance of the heat exchanges occurs in a short time between the condenser, which is placed in a technical compartment outside the cell, and the evaporator placed in the cell, since said condenser must dissipate the heat of the evaporator added to the heat input given by the work of the compressor. Indeed, in a blast chiller, the heat exchanges are calculated in an extremely precise and repeatable way in order to maintain high efficiency and ensure the high level of performance required; reference may be made, for example, to the necessary execution quickness or to the accuracy of the temperatures guaranteed in thermal processing on food.

[0019] Particularly, in said case of a blast chiller operated in reverse cycle according to the known art, at the inlet of the conditioner an excess of heat was found which is not dissipated and/or absorbed in any other way by the refrigeration circuit or by the environment, such as instead it occurs naturally in heat pump operated air conditioners. Indeed, in a blast chiller for food the changes in the state of the gas inside the circuit are regulated in a very precise way, with limited tolerances, the surrounding conditions being more constant and repeatable with respect to an air conditioner. Reference may be made, for example, to the fact that the environmental conditions of a room vary continuously, depending on the season and/or due to the opening of doors and windows, while the cell of a cabinet blast chiller used in restaurants is closed and of small size. Therefore, in principle, in order to function correctly both in direct cycle and in reverse cycle, maintaining good efficiency and with the highest degree of safety and accuracy in food processing, a multipurpose blast chiller should have different dimensions for the condenser and/or for the evaporator, depending on the direction of operation of the circuit.

[0020] Consequently, it has also been found that the aforementioned problems of imbalance in the heat exchanges with reverse cycle cause an excessive formation of frost on the condenser outside the cell, since it is dimensionally too large, with consequent problems of inefficiency which tend to progressively worsen.

[0021] Considering all the above, it has been found that the blast chillers currently available on the market do not provide for the use of hot gas, with reversal of the refrigeration cycle, for the purposes of said defrosting and also for heating the food in the cell. The most advanced solutions of use of hot gas, referred to for example in D1 and D3, are limited to defrosting and include a by-pass line dedicated to this purpose, where said hot gas is intercepted at the compressor outlet, before entering the condenser, so as to enter the evaporator according to the conventional direction of the flow, without undergoing condensation and expansion. It would be impossible to use such a solution for a prolonged time in order to heat the food in the cell, since the refrigeration circuit is only partially engaged by said by-pass line and the benefit given by the thermodynamic cycle would run out quickly, with the blocking of the system and the impossibility to restore it in a short time.

[0022] Another drawback of the known and conventional solutions of multipurpose blast chillers, is that differentiated technologies are used to refrigerate and heat the food in a cell. Indeed, it has been noted that refrigeration is obtained with a conventional refrigeration cycle where an evaporator removes the heat inside the cell while a condenser releases heat to the outside, in the technical compartment. According to the known art of the sector, in order to activate the heating functions inside said cell, said refrigeration cycle is instead turned off, stopping the circuit, and one or more electrical heating resistances are activated in the cell so as to progressively obtain, with the increase of their power and/or duration of action, first the defrosting of the evaporator, then the rapid thawing of the food, after their heating, even a real low temperature cooking treatment, also called slow cooking. By way of example, see the table of prior art (Fig. 1c) which relates to a multipurpose blast chiller of conventional type, with heating resistances; this solution involves considerable costs of electrical energy and does not give all the potentialities offered by the aforementioned refrigeration cycle for heating purposes. Basically, in a multipurpose blast chiller, the system is not optimized from an energy point of view and the overall efficiency can be improved.

[0023] Another drawback found in multipurpose blast chillers which operate in heating concerns the maximum tolerable temperature inside the cell. Generally, in the known technique the refrigeration circuit is turned off and the electrical heating resistances are activated in such a way as to reach in the cell approximately +40 °C in defrosting, and approximately +70 °C or +80 °C in slow cooking. This temperature limit is given, in particular, by the fans which are placed inside the cell to ensure adequate air flow on the evaporator, for the purpose of rapid blast chilling with food safety. Currently, these fans are not certified to operate above +70 °C or +85 °C, according to the technology used; in particular, reference is made to the electronic components of the motor of said fans, which do not tolerate excessive heat. Basically, it has been found that said limit is not given by the heating technology but by the fact that there is no protection system for said electronic components.

[0024] Consequently to the aforementioned drawback, there is also the known problem of a limited range of thermal treatment which can nowadays be carried out in a multipurpose blast chiller for food; in particular, it is not possible to perform treatments above +85 °C.

[0025] Furthermore, there is the problem of excessive use of electrical resistances for heating purposes, with high costs for the consumption of electrical energy and poor energy efficiency of the appliance.

[0026] Considering also these aspects, the need is absolutely evident for the sector to identify more efficient technical solutions from an energy point of view and also convenient from an economic point of view, with maximum food safety. In particular, it is necessary to have a multipurpose blast chiller optimized in its functionality in heating, these combined appliances being increasingly widespread in the sector of professional catering.

Brief description

[0027] The present invention relates to a multipurpose blast chiller (10) for food, provided with a refrigeration circuit of reversible type (100a - 100b) with a differentiated path in the two circulation directions (115, 116), to carry out treatments in the cell (105) with temperature values between -40 °C and +110 °C, with high energy efficiency. A reverse cycle (100b) is provided for heating purposes, where the hot gas leaves the compressor (101) and proceeds with opposite flow (116) with respect to the refrigeration (100a, 115), to enter the evaporator (104) directly and heat the cell (105) without the help of electrical resistances (106) up to a temperature value equal to approximately + 60 °C. Before entering the condenser (102), in the reverse cycle, the gas is deviated to a secondary energy efficiency line (109), suitable for balancing the heat exchanges (102, 104) and protecting the motor (108) of the fans (107) from overheating, enveloping it with capillaries (110) .

Aims and advantages

[0028] The solution described above offers innumerable aims and advantages, which are not to be intended as limiting, since additional ones can be identified in the following, which, although not mentioned, must be in any case included.

[0029] A first aim of the invention was to defrost the evaporator and also to heat the food in the cell of a blast chiller with the same refrigeration circuit used in refrigeration, until a temperature value equal to approximately +60 °C is reached in the cell, to activate the electrical resistances only at higher temperatures; in this way a hybrid heating system is created, with hot gas and heating resistances, which improves the efficiency of the system and significantly limits the electrical energy consumption. Basically, from an operational point of view, with the proposed multipurpose blast chiller, at least the automatic defrosting of the evaporator and the thawing of food are carried out without the heat input of the electric resistances, which remain deactivated. The aforementioned hybrid system is instead used for treatments of food heating and cooking.

[0030] A second aim of the invention, consequent to the aforementioned first aim, was to improve the energy balance relating to the heat exchanges between the evaporator and the condenser when the blast chiller works in reverse cycle. In particular, the proposed solution balances the energy supply provided by the compressor and by the evaporator, which would otherwise be overabundant with respect to the dimensions of the condenser, advantageously dissipating and recovering the excess thermal energy entering the condenser. It is noted, in particular, that the invention makes said cycle reversal possible, in a blast chiller for food, with a better heat exchange in terms of homogeneity and efficiency with respect to the conventional solutions of combined type such as said air conditioners with heat pump reversible cycle, also with a reduced number of components.

[0031] A third aim of the invention was to integrate into a multipurpose blast chiller an advantageous thermal protection system of the electronic components placed inside the cell, for example in the motor of the fans.

[0032] A fourth aim of the invention, consequent to the aforementioned third aim, was to increase the maximum temperature which can be reached in the cell during heat treatments on food, bringing it to approximately +110 °C or more, in such a way as to significantly expand the range of treatments which can be carried out and add innovative functionalities to a multipurpose blast chiller, such as new cooking cycles or the sterilization of the cell with steam.

[0033] A fifth aim of the invention was to integrate a technical solution of combined type, simple from the constructive point of view and easy to produce industrially, which is capable of simultaneously obtaining multiple effects, in a synergetic way.

[0034] Another aim of the invention was to obtain a multipurpose blast chiller capable of carrying out food treatments at temperatures between approximately -40 °C and +110 °C, safe from the sanitary and hygienic point of view, extremely efficient from the energy point of view, with limited overall costs, extremely versatile and with high reliability and ease of use.

[0035] These and other aims and advantages will appear in the following detailed description of execution with the help of the attached drawings whose execution details are not to be intended as limiting but only and exclusively exemplary.

Content of the drawings

[0036] 

Figures 1a, 1b, 1c and 1d represent simplified schemes of refrigeration circuits according to the known art relating to various industrial sectors. In particular, figures 1a and 1b illustrate the refrigeration circuit of a conventional air conditioner for environments, where the first represents the cooling cycle or direct cycle, and the second represents the heating cycle or reverse cycle which includes the functions of defrosting and heat pump. Figure 1c, on the other hand, illustrates the refrigeration circuit of a conventional refrigerator with an evaporator in the cell, where there is also an electrical resistance for its defrosting with standstill cycle; finally, figure 1d illustrates the refrigeration circuit of a modern blast chiller provided with an advanced system for defrosting the evaporator, with a hot gas by-pass line including a defrost valve also called HGDV connected to a logic control unit provided with programs for automatically carrying out the opening and closing also depending on the detection of multiple variable parameters, such as pressure and temperature.

Figure 2 is a simplified scheme of the refrigeration circuit integrated into the blast chiller which is the subject matter of the invention, provided with refrigeration cycle which is reversible and differentiated in both directions, being conventionally represented here with cooling flow.

Figure 3 is a simplified scheme of said refrigeration circuit of figure 2, where particularly the refrigeration cycle has a reverse flow so that the hot gas leaving the compressor directly enters the evaporator, to quickly defrost it and heat the food processing cell. There is also a by-pass sub-circuit configured in such a way as to intercept the same gas in the return phase, before it enters the condenser, using it at the same time to protect the electronic components in the motor of the fans with capillary winding, and to rebalance the heat exchanges in said reverse cycle.

Practical execution of the invention

[0037] With reference also to the schematic figures (Figs. 2 and 3), the present invention proposes a modern blast chiller (10) of the multipurpose type, capable of operating in the cell (105) with temperature values between -40 °C and at least +110 °C; the blast chiller proposed is significantly improved in its functioning in heating, compared to conventional and known solutions, with greater energy efficiency, lower operating costs and a wider range of allowed heat treatments. In particular, the proposed blast chiller is provided with a refrigeration circuit (100, 101, 102, 103, 104) of reversible type (100a, 115) (100b, 116) which advantageously exploits the heat of the gas leaving the compressor (101, 114), also in reverse cycle (100b, 116), singularly taken or in combination with electrical resistances (106) like a hybrid system. In order to optimize the heat exchanges in said reverse cycle, a partially differentiated circuit is provided in the two directions of circulation of the flow (115, 116).

[0038] The refrigeration circuit (100) of the proposed blast chiller (10) in refrigeration (100a) is operated in a conventional way, the flow of gas (115) from the compressor (101) entering the condenser (102) and so on, realizing temperature values between 40 °C and 0 °C in the cell. In heating, the cycle (100b, 116) is instead reversed to create temperature values in the cell (105) between 0 °C and +60 °C, for example to defrost the evaporator (104) or thaw food, while above this value it (100b, 116) works in combination with at least one electrical heating resistance (106) in such a way as to increase said temperature in the cell up to a value at least equal to approximately +110 °C, allowing new forms of cooking or sterilization of the cell.

[0039] More in technical detail, in order to allow said cycle reversal (100b, 116) with an adequate balancing of the heat exchanges between the condenser (102) and the evaporator (104), and simultaneously protecting the electronic components included in the motor (108) of the fan (107), according to the predetermined aims, in the return phase an advantageous deviation of the circuit (100b, 109) is provided, which is conventionally called secondary balancing and protection line (109). It brings the warm gas back into the cell (105), before entering the condenser (102), so as to exploit the excess heat for heating purposes, such as heat recovery, rebalancing the heat exchanges between condenser and evaporator with accuracy. At the same time, it is provided that said secondary line (109) envelops the aforementioned motor (108) of the fan (107) with capillaries (110) in such a way as to provide a localized protection of the electronic components within the cell (105), like an air-conditioned cage where the temperature does not exceed said threshold value of +70 °C even when the temperature in the cell (105) is higher, that is when the electrical heating resistances (106) are active.

[0040] In this way, the combined effect of balancing the heat exchanges (102, 104, 109, 110) in the reverse cycle (100b, 116) is obtained and it is possible to significantly increase the power of the electrical resistance (106) to widen the range of possible treatments in the cell (105), with maximum safety, up to a temperature value equal to approximately 110 °C. It is noted that this limit is not given by the proposed technical solution, which would instead allow higher temperatures, but it is due to the material generally used to insulate the body of modern blast chillers, this being of the polyurethane foam type which degrades at temperatures higher than +110 °C.

[0041] The use of the reverse cycle only (100b, 109, 116) is advantageous first of all in the frequent operations of defrosting of the evaporator (104) and also in the phases of thawing of food, since the heating resistance (106) is not used. For cooking, a heating system of the hybrid type is instead provided, combining the thermal supply of said cycle reversal (10b, 109, 116) with the one of the single or grouped heating resistances (106).

[0042] The proposed blast chiller (10) integrates a logic control unit (111) provided with programs (112) suitable for controlling the gas flows in said circuit (100a, 100b) and particularly when it is operated in reverse cycle (100b, 116), where precise control is required of said secondary line (109, 110) and of the multiple valves involved. For example, in the preferential configuration of the circuit (100a, 100b), the control of the secondary line (109, 110) can be done by means of a temperature probe which opens a modulating two-way valve (113f) when needed. Alternatively, it is possible to leave this valve always open when the 4-way valve (114) leaving the compressor (101), called cycle reversal valve, is of modulating type and is in heating mode having activated said reversal of the flow of the gas (116) to send it directly into the evaporator (104) in the cell (105), and then continue towards the thermostatic valve (103) and then deviate it into said secondary line (109, 110) immediately before entering the condenser (102), as described above. Said programs (112), therefore, automatically manage all the probes in the cell (117) and those integrated in the circuit, and all the valves (103, 113a, 113b, 113c, 113d, 113e, 113f, 114) involved in the direct cycle (100a, 115) (Fig. 2) and in the reverse cycle (100b, 116) (Fig. 3).

[0043] Said programs (112) for the automatic control of said probes and said valves optimize the efficiency of the heat exchange (102, 104) in the heating phase, in reverse cycle (100b, 116), and also manage said cooling system (109, 110) of the fans (107, 108), so that a part of the heat which must be dissipated by the condenser is dissipated on said motor (108), or group of motors, in the cell (105), rebalancing said circuit from the energy point of view. Furthermore, said programs manage the aforementioned hybrid heating system, where the action of said cycle reversal is combined with the action of said electrical heating resistance (106) or group of resistances, so that the resistance is activated only when a predetermined level of temperature (117) is exceeded in the cell (105), for example equal to approximately +60 °C. Finally, said programs (112) control the opening of the modulating two-way valve (113f) to cool the fan (109, 110).

Nomenclature

[0044] 

(10) multipurpose blast chiller for food, with reversible cycle, according to the present invention (Figs. 2 and 3);

(100) refrigeration circuit of the proposed blast chiller, with reversible cycle, being operated in direct cycle in refrigeration (100a) and in reverse cycle in heating (100b);

(101) compressor;

(102) condenser;

(103) thermostatic valve, acting as a controlled expansion means;

(104) evaporator in the cell;

(105) cell, for the thermal treatment of food from approximately -40 °C to +110 °C;

(106) single or grouped electric heating resistance;

(107) fan in the cell;

(108) motor of the fan;

(109) energy efficiency secondary line. It is active only in the reverse cycle to balance the heat exchanges and to protect the motor of the fans from overheating;

(110) capillaries, of the secondary line, to envelop the motor like a cooling means;

(111) logic control unit;

(112) operating and control programs, with reverse cycle hot gas management for defrosting and heating, according to the aims of the invention;

(113a -113e) non-return valve;

(113f) 2-way valve, of the modulating type, for controlling the flow in the secondary balancing and protection line;

(114) 4-way valve, of the modulating type, for the cycle reversal and for the control of the flow leaving the compressor, in both directions;

(115) direction of the flow in refrigeration, with direct cycle;

(116) direction of the flow in heating, with reverse cycle;

(117) probe for temperature detection.

[0045] Nomenclature relating to the prior art (Figs.1a - 1d):

(200a - 200b) refrigeration circuit with reversible cycle, for air conditioners;

(201, 301, 401) compressor;

(202, 302, 402) condenser;

(203, 303, 403) expansion means, such as a lamination member or a thermostatic valve;

(204, 304, 404) evaporator;

(205a - 205d) non-return valve;

(206) 4-way valve;

(207, 309, 411) logic control unit;

(30) blast chiller for food, of conventional type;

(300) refrigeration circuit of a blast chiller;

(305, 405) cell, for the treatment of food between -40 °C and +85 °C;

(306) electrical heating resistance;

(307) fan;

(308, 407) conventional direction of the gas flow, in cooling;

(40) blast chiller for food, with automatic defrost;

(400) refrigeration circuit with hot gas by-pass line;

(406a - 406d) probes for detection of temperature and pressure;

(408) hot gas by-pass line, for defrosting;

(409) flow control valve;

(410) direction of hot gas flow during defrosting;

(412) operating and control programs, with management of hot gas in defrosting on by-pass line.

Claims

1. Multipurpose blast chiller (10) for food with reversible cycle (115, 116), with high energy efficiency, which is suitable for operating in a treatment cell (105) with temperature values between -40 °C and at least +100 °C; said multipurpose blast chiller (10), with a refrigeration circuit (100) including a compressor (101), a condenser (102), a thermostatic valve (103) and an evaporator (104) placed in the cell (105), which are sequentially ring-connected with each other, with at least: a flow regulation valve, a cell temperature probe (117), a fan (107) serving said evaporator (104, 105) and a logic control unit (111) of said refrigeration circuit (10, 100); said refrigeration circuit (100) being operable in a direct cycle (100a, 115) to work in refrigeration with evaporation temperatures lower than 0 °C and temperature values in the cell between -40 °C and 0 °C, where the flow of hot gas leaving the compressor (101) crosses continuously, in sequence: first the condenser (102), afterwards the thermostatic valve (103), then the evaporator (104) in cell (105), and afterwards it returns into the compressor (101); said multipurpose blast chiller (10), provided with means for the automatic defrosting of said evaporator (104) and means for heating the food in the cell (105); said multipurpose blast chiller (10), with at least one electrical heating resistance (106) inside the cell (105); said multipurpose blast chiller (10), characterized in that said refrigeration circuit (100) can be also operated in reverse cycle (100b, 114, 116) to work in heating, with temperature values in the cell (105) higher than 0 °C , where said hot gas leaving said compressor (101) is directed (111, 114) with opposite flow (116) with respect to said refrigeration (100a, 115) to directly enter said cell (105) through said evaporator (104) and afterwards cross said thermostatic valve (103); said refrigeration circuit (100), with a four-way valve (114) which is placed at the outlet of the compressor (101) and acts as a cycle reversal valve; said refrigeration circuit (100), with valves (113a - 113d) placed before and after said thermostatic valve (103) to maintain in said reverse cycle (100b, 116) the same crossing direction of said direct cycle (100a, 115); said refrigeration circuit (100), including a secondary line (109) which is active only in said reverse cycle (100b, 113e - 113f, 116) with combined efficiency and protection functions, which (109) departs from it (100) and gets into it (100) again between said thermostatic valve (103) and said condenser (102); and wherein said secondary line (109) deviates said hot gas, which is at a temperature value between 55 °C and 65 °C, to bring it back inside the cell (105) where it branches out locally into capillaries (110) and then returns to a controlled temperature value (111) depending on the heat exchange between said condenser (102) and said evaporator (104), like an energy balancing means with possible heat recovery in the cell (105); said secondary line (109), furthermore, with said capillaries (110) which envelop the electronic components placed in the cell (105) keeping them at a temperature value below their overheating threshold, like a cooling means; and wherein, to operate with temperature values in the cell (105) between 0 °C and +60 °C, said multipurpose blast chiller (10) uses only the heat input of said refrigeration circuit (100) operated in reverse cycle (100b, 109, 116) and on the other hand, to operate with higher values, it (10) adopts a hybrid heating system which combines the heat input of said reverse cycle (100b, 109, 116) with the heat input of said electrical heating resistance (106); and wherein the values indicated are considered with a tolerance equal to +/- 10%.

2. Multipurpose blast chiller (10) according to the previous claim, characterized in that said hybrid heating system (100b, 106, 109, 116) operates with temperature values in the cell (105) between +60 °C and +110 °C; and wherein the values indicated are considered with a tolerance equal to +/- 10%.

3. Multipurpose blast chiller (10) according to claim 1 or 2, characterized in that said capillaries (110) envelop the motor (108) of said fan (107) like a means for cooling it when the blast chiller (10) operates in heating with said hybrid system (100b, 106, 109, 116); said motor (108) including electronic components having said overheating threshold equal to +70 °C.

4. Multipurpose blast chiller (10) according to claim 1 or 2, characterized in that said capillaries (110) envelop the motor (108) of said fan (107) like a means for cooling it when the blast chiller (10) operates in heating with said hybrid system (100b, 106, 109, 116); said motor (108) including electronic components having said overheating threshold equal to +85 °C.

5. Multipurpose blast chiller (10) according to claim 1 or 2 or 3 or 4, characterized in that with said heating system in only reverse cycle (100b, 109, 116) it carries out in the cell (105) at least said defrosting of the evaporator (104) and the thawing of the food; and wherein, on the other hand, with said hybrid heating system (100b, 106, 109, 116), it (10) carries out in the cell (105) at least the treatments of cooking food and/or sterilization cycles with steam.

6. Multipurpose blast chiller (10) according to claim 1 or 2 or 3 or 4 or 5, characterized in that said logic control unit (111) is provided with specific programs (112) suitable for simultaneously controlling the gas flows, in said circuit (100, 100a, 100b), both in refrigeration (100a, 115) and when it operates in reverse cycle (100b, 116) in heating, by means of valves (113a - 113f, 114) and at least one temperature probe (117) placed in the cell and one placed in correspondence with the secondary line (109); and wherein said logic control unit (111, 112), by means of said probes, opens as needed a two-way valve (113f) of modulating type which is included in said secondary line (109), regulating said combined efficiency and protection functions.

7. Multipurpose blast chiller (10) according to the preceding claim, characterized in that if said four-way valve (114) is of the modulating type, said logic control unit (111, 112) leaves always open said two-way valve (113f) of the secondary line (109).

Drawing