ES2248178T3 - REFRIGERATION INSTALLATION FOR LIQUID FOOD PRODUCTS. - Google Patents

Abstract

The liquid comestible cooler has a coolant circuit (1) with a direct cooler (2), an ice store (3) and a refrigerator (5), which can be connected to the direct cooler or the ice store. The connection is controlled by a switch (6). The refrigerator can have a dew point regulator (54) which operates the switch. An Independent claim is included for method for using the cooler.

Description

Refrigeration installation for products liquid food

The invention relates to an installation of refrigeration for liquid food products, especially for milk, with an intermediate refrigerant circuit comprising a direct refrigerator, an ice deposit and a group of refrigeration.

In the processing of food products liquids, especially in milk processing, it is necessary refrigerate the milk supplied quickly and reliably at low temperatures By the rules of the food code, the product food, for example milk, cannot be refrigerated directly with cooling agents; it has to intercalate a refrigerant compatible with the products food, usually water. Temperatures are desirable in the approx. 4 ° C, for which temperatures of the cooling agent of about 0 ° C - 1 ° C. The milk cooling facilities used for this cause a considerable part of the acquisition and service expenses of the dairy. For a prior published use they are known cooling facilities for milk, in which for refrigeration is called an ice deposit. In a warehouse of ice, at times during which milk is not supplied, generates a layer of ice on the cooling pipes of the ice deposit Ice is generated on the tubes, until it has reached a desired amount of ice or until it Produce a milk supply. When milk is supplied, the tank of ice is switched to the cooling regime. During this, the cooling water used to cool milk is made go through the ice deposit to which energy is extracted by the melting of ice stored on the tubes. In this way, the Milk can be refrigerated at the desired temperature. A disadvantage of the known ice deposits is that they require a lot of space of construction and cause high acquisition and service costs. In addition, they depend on sufficiently long loading pauses to perform the storage service. They are not suitable for operation with a continuous transformation service of milk, as it predominates today. It is also difficult regulate the cooling capacity of the ice bin, because at cause of its large mass that is further increased by the ice accumulation, reacts with inertia to changes.

It is also known to provide, in addition to ice bin, a direct-acting refrigerator (refrigerator direct) to ensure sufficient milk cooling even in case of load peaks that exceed the capacity of the ice deposit or in case of insufficient storage of ice. The direct refrigerator made, for example, as plate heat exchanger, is designed only for a brief operation and, therefore, is sensitively sized smaller compared to the refrigerator with deposit of ice. Although with the additional direct refrigerator you can briefly compensate for insufficient tank capacity ice, also does not serve to achieve continuous operation of the milk cooling facility. In addition, the forecast of a additional direct refrigerator further increases the costs of Acquisition and service.

A refrigeration installation for products Liquid food is known from US2512576.

The invention aims to provide a refrigeration installation for food products liquids of the type mentioned at the beginning, which is less complicated and can be applied better.

The solution according to the invention consists of a refrigeration system for liquid food products with the features of claim 1. Some variants advantageous result from the subordinate claims.

Some terms are explained below. employees:

Liquid food products are understood as food and condiments in liquid state.

An ice bin is a refrigerator that, In a storage regime, an agent of cooling for icing while in a cooling regime, the cooling agent is passed by the refrigerator being cooled by ice.

A direct refrigerator is a refrigerator in the that the supplied cooling agent is used directly for the cooling of a medium to be cooled.

A refrigeration group means a Refrigeration machine that has no refrigerator. Usually, the refrigeration group comprises a compressor, a condenser and at least one throttle valve.

For the nominal power of a refrigerator, understands a power for which the fridge.

The minimum power of a refrigerator is understands the power below the nominal power, with which the refrigerator can still work without failures of refrigerator operation or damage.

The ice bin is sized for a lower cooling capacity than the direct refrigerator and for a cooling capacity greater than a minimum cooling capacity of direct refrigerator Thus, the cooling installation for liquid food products can be operated in direct cooling regime over a wide range of need for cooling power. In addition, with a low need for cooling power, falling below the minimum cooling capacity, can be switched to the rate of tank cooling by disconnecting the direct refrigerator. This has the advantage that, on the one hand, the installation of refrigeration for liquid food products can work for longer in the direct cooling regime with a lower energy expenditure and, on the other, that can be better adapted to  load fluctuations In addition, in this way, the ice deposit which is expensive both in terms of acquisition cost and regarding its operation, it can be sized smaller than in refrigeration facilities for food products liquids according to the state of the art. During operation normal, the cooling group is attached to the refrigerator direct and connects only in case of exception with the deposit of ice. Then, the ice bin serves only for refrigeration with a need for refrigerating power less than the minimum cooling capacity or to cover load peaks. By consequently, the direct refrigerator is complemented by the ice deposit in terms of its power, both upwards and down; despite this variability according to the invention, in In total, only one cooling group is required.

The direct refrigerator is made as runoff refrigerator. In comparison to other types of construction, the runoff refrigerator has the advantage of which can be adapted to the corresponding load along a wide range Compared to heat exchangers of plates or tube bundle coolers that have only one regulation range of approximately 10 to 15%, the runoff refrigerator adapts to load changes of up to 30%, in certain circumstances up to 50%. The refrigerator of runoff can also cool to lower temperatures (approx. 0.5ºC) than a plate heat exchanger (2ºC). While than plate heat exchangers and refrigerators Tubular can be destroyed by icing in If the load is too low, this danger does not exist or exists only to a much lesser extent in refrigerators than runoff, as they freeze only with low loads and even Then they are not destroyed. For this reason, the refrigerator of runoff can be applied better and is more reliable.

According to a convenient embodiment, the switching device features a temperature regulator of evaporation that acts on the cooling group. This shape, it is possible to adjust the evaporation temperature which is important for both the cooling capacity and the degree of cooling device action. This is advantageous, especially in case of operation according to the invention of the Same cooling group with different refrigerators. Is based in the knowledge that different types of refrigerator They require different evaporation temperatures. Therefore the switching device is configured such that when the direct refrigerator is connected to the group of cooling, the evaporation temperature is set to a suitable value for operation with the direct refrigerator, while for operation with the ice bin, the evaporation temperature is set to a suitable value for the ice deposit In this way, with the same group of cooling, the two refrigerators can be operated with a favorable degree of action despite its different type of construction and its different temperature requirements evaporation

In an advantageous embodiment it is provided a plurality of cooling devices that they present respectively a direct refrigerator and a group of cooling, preferably three cooling devices. The plurality of cooling devices allows a even better adaptation of the cooling system to liquid food products to the corresponding need for refrigeration power. So, in case of a low need for cooling capacity, just be connected, for example, One of the cooling devices. in case of need average cooling capacity have to be connected two of the cooling devices and finally in case of a higher need for cooling power, they have to be All cooling devices connected. It has been credited particularly provide three refrigerators and groups of refrigeration; in case of low requirements regarding the adaptability to the need for cooling power can also be enough with two.

Advantageously, the devices of cooling are sized for different powers refrigerators In this way, with the same number of devices cooling an even finer adaptation of the corresponding cooling capacity to the need for power refrigerating This type of power adaptation results especially advantageous in those cooling devices, whose cooling groups have a fixed power adjusted In this way, groups of simple construction refrigeration and therefore more economic, whose compressors are not adjustable, being able to be carried out, however, by switching according to the invention and the connection of the cooling devices depending on the load, a fairly fine adaptation to the corresponding need of refrigerating power. Preferably, one of the devices cooling is sized to meet the need for basic load It has been revealed that even with a load profile variable, there is often a load value that, except for pauses loading, it exists practically all the time. This value of load is also called basic load. In this way, it get that at least for the frequent basic load there is a Direct cooling device properly sized.

Next, the invention is described. in detail referring to the drawing that shows examples of advantageous embodiments of the invention. In detail, they show:

Figure 1 a cooling installation for liquid food products according to the invention, according to a first exemplary embodiment;

Figure 2 the cooling installation for liquid food products according to the invention, according to a second exemplary embodiment, with several devices of refrigeration;

Figure 3 a load profile and selection derived from it from refrigerators according to the procedure in which base the invention.

A refrigeration installation for products liquid foods according to the invention is made as milk cooling facility. It comprises a circuit of cooling water 1, a direct refrigerator 2, a tank of ice 3, switching valves 4, a cooling group 5 as well as a switching device 6. Both direct refrigerator 2 as the ice bin 3 are connected to the water circuit coolant 1. The coolant water circuit is closed, a through a heat exchanger not shown that is in contact with the milk to be refrigerated or with another product liquid food to be refrigerated. In the example of embodiment represented, in addition, a cooling agent circulates through the direct refrigerator 2, the ice tank 3, the valves switching 4 and the cooling group 5.

In the embodiment shown, the direct refrigerator 2 is made as a refrigerator of runoff Inside the direct refrigerator 2 are arranged a heat exchange plate 21 and a system of runoff 22. The runoff system is connected, to through a feed duct 23 and a duct return 24, with switching valves 4. The ice bin 3 presents inside a tube / plate system 31, whose tubes are connected to each other and over which it can be stored ice. The tube / plate system 31 is connected, through a feed duct 32 and a return duct 33, with switching valves 4.

Switching valves 4 serve as an element of regulation that can be switched between two positions. In addition to the supply and return ducts 23, 24, 32, 33 are connected to switching valves 4 a low conduit pressure 58 leading to the cooling group 5 and a duct of high pressure 59 coming from the cooling group 5. The valves switching 4 connect, in a first position, the conduits of supply and return 23, 24 with low pressure ducts and high pressure 58, 59; in a second position, connect the feed and return ducts 32, 33 with the ducts Low pressure and high pressure 58, 59. Switching valves 4 are connected to the switching device 6 via a line of control 41.

The cooling group 5 comprises a compressor 51 connected to a motor 52 and driven by it, a condenser 54, as well as a regulating valve 56. The duct low pressure 58 is connected to a low pressure side of the compressor 51. Beside high pressure compressor, through a high pressure conduit 53 is connected one side of the capacitor 54; the other side of the capacitor 54 is connected, to through a conduit 55, with one side of the regulating valve of pressure 56. The high duct is connected to its other side pressure 59. In addition, a control line 57 is provided that joins the  pressure regulating valve 56 with switching device 6.

Switching apparatus 6 is connected, to through ducts 63, 65, with sensors 64, 66 for temperature or the flow of the cooling water in the water circuit refrigerant 1. Alternatively or additionally, they may be corresponding sensors are also provided for measuring the corresponding parameters of milk. The switching device 6 acts, through a control line 62, on the motor of drive 52 of the cooling group 5, as well as, through of control line 41, on switching valves 4. The switching apparatus 6 also has a profile tank of load 61.

The device is operated as follows way. The cooling agent circulates in the water circuit refrigerant 1 from the milk heat exchanger (no represented) returning to direct refrigerator 2 and to the storage tank ice 3. Coolant temperature or flow rate is recorded through sensors 64, 66 and are transmitted to the apparatus of switching 6. From this data, as well as from the load profile stored in memory device 61, the switching device 6 determines the necessary cooling capacity to refrigerate the milk, and this determines the regime of the 7, 7 'cooling devices. So, the apparatus of switching 6 selects from among the refrigerators 2, 3 that one, whose cooling capacity is closer to the power Refrigerator needed.

First, it is assumed that the direct refrigerator 2. Then, through the control line 41, a signal is emitted to the switching valves 4, by means of the which are switched to the first position. In this position, the high pressure and low pressure ducts 58, 59 are connected with the supply and return ducts 23, 24 of the direct refrigerator Therefore, direct refrigerator 2 is connected to cooling group 5. Then, the agent cooling circulates in the circuit formed by the group of cooling 5 and direct refrigerator 2, through the switching valves 4. Via control line 62, excites drive motor 52 of the cooling group. TO via the regulation line 57, the switching device 6 controls the regulating valve 56. The control is carried out in such a way so that the cooling group 5 adjusts to a temperature evaporation in the range of -4 ° C to -2 ° C. In this regime, the milk is refrigerated, through the water circuit refrigerant 1, direct refrigerator 2 and group of 5 cooling connected to it, with a good degree of efficiency, to the desired temperature of approx. 0 to 1 ° C.

Assume now that it is not being supplied no or only little milk, the necessary cooling capacity less than the minimum power of the direct refrigerator 2. The switching apparatus 6 excites switching valves 4 a through control line 41, so that it switches to its second position. For this, the switching device 6 emits by control line 41 an appropriate control signal to the valves of switching 4. In addition, switching apparatus 6 emits a signal corresponding to drive motor 52, through the control line 62. Now, cooling group 5 is connected to ice container 3 and the cooling agent circulates through the circuit formed in this way. The fridge direct 2 is disconnected. In addition, the switching apparatus 6 excites, through regulation line 57, the valve pressure regulation 56, so that a temperature results evaporation in the range of -15 to -8 ° C. This shape, the ice bin 3 can be operated in the regime of storage. This regime is especially appropriate when practically no refrigerating power is required; that is to say, in a pause of loading. It can last until the pause of load or until the ice bin 3 has reached a maximum ice storage Then the switching device 6 disconnects drive motor 52 from the cooling unit 5 via control line 62. Switching apparatus 6 You can also disconnect the cooling unit when it is no longer there is no or only little need for lower cooling capacity at minimum power, with the ice tank 3 sufficient ice. Then, the ice container 3 refrigerates on storage. Switching valves 4 can also be configured in such a way that they can adopt intermediate positions in which both refrigerators 2, 3 are connected to the group of refrigeration.

In figure 2 a second is represented exemplary embodiment of the refrigeration installation for liquid food products according to the invention. Is it so provided, in total, three cooling devices (7, 7 ', 7 ''), whose structure corresponds respectively to that which is represented in figure 1, being provided for all cooling devices only a switching device 6 '. The third cooling device (7 '') has a different structure, no ice deposit being provided 3. Unlike the embodiment according to figure 1, the switching apparatus 6 'in the embodiment shown in figure 2 presents a selection unit 69. This unit of selection 69 is set to select, depending on the necessary cooling capacity, those refrigerators, whose added cooling power is closer to the power Refrigerator needed. Depending on this selection, the device switching 6 connects the valves 8, 8 ', 8' 'that connect the cooling devices 7, 7 ', 7' 'with the water circuit refrigerant, thus leaving free access to the devices of selected cooling and closing it towards the devices Refrigeration not selected. Chilled water through the cooling devices 7, 7 ', 7' 'circulates at a collecting container 9 in which the deposits of ice 3, 3 ', from where it reaches the water circuit again refrigerant 1.

The refrigeration installation for products liquid foods according to the second embodiment It works in the following way. With the help of sensors 64, 65 and of a load profile stored in the memory device 61 determines the necessary cooling capacity. The powers Refrigerators needed, determined over a period of 24 hours, are represented with the help of an example in the figure 3. Then, switching device 6 selects, by means of selection unit 69, those cooling devices, whose added cooling power is closer to the cooling power necessary. For this, the switching device 6 excites the correspondingly the valves 8, 8 ', 8' 'and the valves of 4, 4 'switching.

An example of such a selection is represented in figure 3. It is assumed that the device cooling 7 has a power in the regime of 2300 kW direct cooling, 7 'cooling device a power in the direct cooling regime of 1600 kW and the 7 '' cooling device a power in the regime of 1700 kW direct cooling. Narrow columns correspond to the cooling capacity required in the period corresponding, while the shaded areas represent the times of use of the corresponding devices of cooling 7, 7 ', 7' '. The line that borders the shaded areas indicates the power used in the regime of direct cooling In the load profile, in the period designated by "phase I", at dawn, approximately between 3:00 a.m. and 6:00 a.m., a cooling capacity is required that more It is close to that of the 7 '' cooling device. So, switching device 6 connects this device refrigeration. In the period of approx. 6:00 to 8:00, designated by "phase II", the need for cooling power rises, so that to cover it, the combination of the 7 'and 7' 'cooling devices. Now, the apparatus of switching 6 additionally connects the devices of 7 'cooling and makes them work in the regime of direct cooling In the next period designated by "phase III ", the need for cooling capacity has increased so much that now the need for cooling power is better covered by a combination of the cooling devices 7 and 7 '' in direct cooling regime. To do this, the device switching 6 additionally connects the cooling device 7, now disconnecting from the cooling water circuit 1 the 7 'cooling device that is no longer required, by means of the 8 'valve. At the same time, due to the stored load profile in load profile memory 61, waiting for load peaks imminent, to prevent, switching device 6 switches the 7 'cooling device to the second switching state by operating the switching valves 4 ', whereby the group of 5 'cooling connects to the 3' ice bin. Now him 7 'cooling device is in the regime of storage. In the next "phase IV", the need for cooling capacity has risen again, so that the appliance switching 6 additionally connects the three devices of cooling 7, 7 ', 7' ', for which the device 7 'cooling is put back into the first connection state (direct cooling regime). In the next "phase V" partly load peaks occur, while the need for cooling capacity is higher than the cooling powers of All cooling devices 7, 7 ', 7' 'together. In the Figure 3, this is noted because the narrow column exceeds the line that borders the shaded areas. According to the invention, despite of these load peaks, cooling can be achieved enough thanks to the 3 'ice bin, if necessary through the ice bin 3. In the following "phases VI-XI "decreases the cooling capacity necessary, and switching device 6 connects or disconnects from correspondingly cooling devices 7, 7 ', 7' '. In phases "X" and "XI", the cooling device 7 'or 7 is switched by switching apparatus 6 to the rate of storage to accumulate ice in 3 'and 3 ice deposits awaiting the next "phase XII". In phase "XII", the need for low cooling capacity, therefore, below Minimum power limit of the smallest direct refrigerator. The direct refrigerators 2, 2 ', 2' 'are disconnected; to provide this low cooling power, the deposits of 3 or 3 'ice. It is worth mentioning that, conveniently, a Storage of ice deposits 3, 3 'is not performed necessarily already in the time periods of downward load, as in the "phases VI-X", but advantageously, only in "phase XII" (in the example shown, of dawn), when due to the load profile stored in the memory device, imminent use of deposits is expected of ice 3, 3 '. The same is valid for storage before the expected appearance of load peaks. This mode of operation has the advantage that it is not necessary to maintain 3, 3 'ice deposits in storage status during unnecessarily long periods, in which case there would be a need for additional energy

It is also worth mentioning that the power of 7 '' cooling device was selected such that, except in "phase XI" and "phase XII", it can work all the time in direct cooling regime; this means that this cooling device is coordinated with the Basic charging need.

Claims (5)

1. Refrigeration installation for liquid food products, especially for milk, with an intermediate circuit (1) of refrigerant comprising a direct refrigerator (2), an ice tank (3) and a cooling group (5), being provided a switching device (6) with a regulating element (4), configured to connect the cooling group (5) optionally with the direct refrigerator (2) or with the ice tank (3), characterized in that the direct refrigerator ( 2) It is made as a runoff cooler and the ice bin (3) is sized for a cooling capacity below the nominal power of the direct refrigerator (2) and for a cooling capacity exceeding a minimum power of the direct refrigerator (2). 2. Refrigeration installation for liquid food products according to one of the preceding claims, characterized in that the cooling group (5) has an evaporation temperature regulator (54) on which the switching device (6) acts. 3. Refrigeration installation for liquid food products according to one of the preceding claims, characterized in that a plurality of refrigeration devices (7, 7 ', 7'') are provided, respectively having a direct refrigerator (2, 2', 2 '') and a cooling group (5, 5', 5 ''), preferably in an amount of three. 4. Refrigeration installation for liquid food products according to claim 3, characterized in that the refrigeration devices (7, 7 ', 7'') are sized for different cooling capacities. 5. Refrigeration installation for liquid food products according to claim 3 or 4, characterized in that one of the refrigeration installations (7 '') is sized to cover a basic load requirement.