Cooling appliance

Abstract

 Cooling appliance (1) with a freezer compartment (2) and at least one refrigeration compartment (3), which comprises a compressor (4), a condenser (5), and at least two cooling units associated to the freezer and refrigeration compartments and connected in series, situated in a refrigeration-agent circuit. The cooling unit of the refrigeration compartment is a static evaporator (6), the cooling unit of the freezer compartment is a no-frost evaporator (7), and the cooling appliance (1) comprises a single temperature regulator (8).

Description

TECHNICAL FIELD

[0001] This invention relates to cooling appliances, in particular domestic cooling appliances with compartments with different temperatures.

PRIOR ART

[0002] Cooling appliances with a freezer compartment and at least one refrigeration compartment are well known in the prior art and comprise a compressor, a condenser, and at least two cooling units attached to the freezer and refrigeration compartments connected in series and situated in a refrigeration-agent circuit.

[0003] Patent US3009338 discloses a cooling appliance of the type described above, wherein the cooling units are two static evaporators that form an evaporator system, the evaporator of the refrigeration compartment being of lesser refrigerating power, connected fluidly next to the evaporator of the freezer compartment of greater refrigerating power and in which the control circuit that regulates the compressor includes a thermostat that receives the temperature of the evaporator of the refrigeration compartment, it doing this by means of a temperature sensor connected to said thermostat, which is disposed in thermal contact with the evaporator.

[0004] In these cooling appliances, the regulating of the temperature of the freezer compartment is performed indirectly through the regulating of the temperature of the refrigeration compartment.

DISCLOSURE OF THE INVENTION

[0005] It is the object of the invention to provide a cooling appliance, as defined in the claims.

[0006] The cooling appliance of the invention, which has a freezer compartment and at least one refrigeration compartment, comprises a compressor, a condenser, and at least two cooling units associated with the freezer and refrigeration compartments and connected in series, situated in a refrigeration-agent circuit. The cooling unit of the refrigeration compartment is a static evaporator, the cooling unit of the freezer compartment in a no-frost evaporator, and the cooling appliance comprises a single temperature regulator.

[0007] No-frost evaporators, already known in the prior art, are batteries that cool as a result of forced-air circulation, their main advantage being that they do not generate frost. However, in the prior art a no-frost evaporator has not been combined with a static evaporator connected in series and with a single temperature regulator, due to the technical preconceptions preventing the expert in the field from approaching said solution. It has been shown, however, that the aforementioned solution may function in an optimal manner, with a simple and low-cost cooling appliance being obtained.

[0008] These and other advantages and characteristics of the invention will be made evident in the light of the drawings and the detailed description thereof.

DESCRIPTION OF THE DRAWINGS

[0009] 

Figure 1 shows a lateral and cross-sectional view of an embodiment of a cooling appliance of the invention.

Figure 2 schematically shows a diagram of the refrigeration circuit used in the cooling appliance of Figure 1.

DETAILED DISCLOSURE OF THE INVENTION

[0010] Figure 1 shows a cooling appliance 1 in accordance with an example of the embodiment. In said embodiment the cooling appliance 1 is made up of a freezer compartment 2 and a refrigeration compartment 3 with different temperatures, and an evaporator system that allows said compartments to be cooled and which is made up of two evaporators. These evaporators are associated to the cooling compartments, the evaporator of the refrigeration compartment 3 being a static evaporator 6 and the evaporator of the freezer compartment 2 being a no-frost evaporator 7.

[0011] The operating of the cooling appliance 1 is controlled by regulating the temperature of the refrigeration compartment 3, and for that purpose the cooling appliance has a temperature sensor 10 in the refrigeration compartment 3. The sensor sends the temperature to a temperature regulator 8, which comprises a temperature selector switch 12 that allows the user to select the required temperature in the refrigeration compartment 3.

[0012] Figure 2 schematically shows a diagram of the refrigeration circuit 9, which allows the refrigeration agent to circulate. Said circuit 9 is made up of a compressor 4, a condenser 5, a filter 13, a no-frost evaporator or battery 7 associated with the freezer compartment 2 and a static evaporator 6 associated with the refrigeration compartment 3 connected in series, the static evaporator 6 being fluidly connected next to the no-frost evaporator. The circuit 9 is also made up of a refrigeration-agent collector 14 and an exchanger 15.

[0013] In the cooling appliance 1 of the invention, the operating of the refrigeration circuit 9 is controlled simply by regulating the temperature of the refrigeration compartment 3. The cooling of the freezer compartment 2, which is not regulated, is carried out at the same time as that of the refrigeration compartment 3, as each time that the refrigeration circuit 9 is switched on at the request of the refrigeration compartment 3, the refrigeration agent is conducted firstly to the no-frost evaporator 7, thereby ensuring that it is cooled. It is, therefore, a cooling appliance 1 that is partially cooled by means of the forced circulation of cold air in the freezer compartment 2, and by means of convection in the refrigeration compartment 3.

[0014] The refrigeration circuit 9 is switched on when the sensor 10 of the refrigeration compartment 3 detects an upper threshold temperature Ton, and switched off when the sensor 10 detects a lower threshold temperature Toff. The user preselects an operating temperature for the refrigeration compartment 3 by means of a temperature selector switch 12. This selected temperature is a set point temperature and the temperature regulator 8 has Ton and Toff values allocated at each temperature set point.

[0015] In order to guarantee that the temperature of the freezer compartment 2 is kept constantly below -18° C, a balance is sought in the refrigeration circuit 9 between the cooling programmed by means of the temperature selector switch 12 for the refrigeration compartment 3 and the cooling of the freezer compartment 2. Balance is achieved by proportioning the static 6 and no-frost 7 evaporators in such a way that in the cooling period of the refrigeration compartment 3, the no-frost evaporator 7 must be capable of cooling the freezer compartment 2 in order to keep it at a temperature that is always below -18° C. For this purpose, once a suitable no-frost evaporator 7 has been proportioned, the static evaporator 6 capable of cooling the refrigeration compartment 3 to the temperature set points is proportioned by determining the necessary tube length and/or the plate surface. A no-frost evaporator 7 for the freezer compartment 2 may always be proportioned with a considerable cooling capacity to ensure the temperature is kept well below -18° C, although it should be remembered that an over-sized evaporator involves an increase in cost and that overcooling also involves an increase in energy consumption.

[0016] In addition, in a preferred embodiment the cooling appliance 1 comprises, as a safety measure, a safety temperature sensor 11 in the freezer compartment 2. Said safety temperature sensor 11 sends the temperature in the freezer compartment 2 to the temperature regulator 8 so that said temperature regulator 8 may act accordingly in the event of said temperature rising above -18° C.

[0017] When the sensor 10 of the refrigeration compartment 3 detects a temperature Ton the refrigeration circuit 9 switches on. The temperature regulator 8 receives the signal from the sensor 10 and switches on the compressor 4, which compresses the refrigeration agent in a gaseous state and sends it overheated to the condenser 5. In the condenser 5 the overheated gas gives off heat, transferring it to the surrounding atmosphere and it gradually condenses. At the end of the condenser 5 the refrigeration agent is in a liquid state.

[0018] When the refrigeration agent exits the condenser 5 it passes through a filter 13, in which any possible moisture molecules it may contain and possible particles that may later obstruct the circuit 9 are eliminated.

[0019] Once the refrigeration agent has passed through the filter 13, it is conducted through a capillary tube 16 with a very small inner diameter to the no-frost evaporator 7. The function of the capillary tube 16 is to regulate the pressure of the refrigeration agent, reducing it from the condensation pressure (high) to the evaporation pressure (low).

[0020] The refrigeration agent then enters the no-frost evaporator 7, which is situated next to the freezer compartment 2 along with a fan (not shown in Figure 1), there being situated at the intake of the evaporator 7 an expansion unit 17 that forms the connection between the capillary tube 16 with a very small diameter and the tubular pipe of the evaporator 7, which is larger. Out of the capillary tube 16 comes the refrigeration agent in a liquid state at low pressure, and following the expansion 17 and all the way along the evaporator 7 a gradual evaporation and a rapid cooling takes place. The refrigeration agent takes the ambient heat surrounding the evaporator 7, which in the case of the no-frost evaporator 7 is the air moved by the fan. The air cools on passing through the evaporator 7, as it transfers part of its energy in the form of heat to the refrigeration agent, which uses it to continue its evaporation, thereby causing cooling as a result of forced-air circulation.

[0021] Once the air has been cooled and dried, when happens because it loses the moisture it transports on being condensed in the wings of the evaporator 7, which are cold, it is sent to the freezer compartment 2 by means of the fan. In said compartment the air takes the heat of the food stored in it and transports it again to the no-frost evaporator 7.

[0022] As the whole of the no-frost evaporator 7 is filled with the refrigeration agent that is evaporating, it moves to the static evaporator 6 of the refrigeration compartment 3, in which it continues evaporating to until, at the end of it, all the refrigeration agent is in a vapour state. The static evaporator 6 is positioned behind the rear wall of the refrigeration compartment 3 for aesthetic reasons, the exchange of heat between the evaporator 6 and the refrigeration compartment 3 taking place through said wall.

[0023] The cooling of the refrigeration compartment 3 takes place as a result of natural convection, as the air that is closer to the location of the evaporator 6 cools and descends, as it is denser than the hot air, and the gap left by the descending air is immediately occupied by hot air, the process being repeated continuously.

[0024] When the refrigeration agent exits the static evaporator 6 it moves to the collector 14 where it is stored. Due to the fact that the cooling appliance 1 may operate at different ambient temperatures, and to the fact that the case may arise in which the refrigeration agent is sent in a partially liquid state to the compressor 4, the collector 14, which is situated at an ambient temperature and in which an expansion takes place, allows a separation of phases to occur, thereby ensuring that the refrigeration agent is in a gaseous state and may therefore be sent in this state to the compressor 4.

[0025] After the refrigeration agent has exited the collector 14 in a gaseous state it begins moving towards the compressor 4 through the suction pipe or exchanger pipe 15. There it comes into contact the capillary tube 16, which conducts the refrigeration agent in a liquid state towards the no-frost evaporator 7, with the suction tube 15, locating it inside it or attaching it to its outer surface, with the result that part of the heat of the fluid passing through the capillary tube 16 is transferred to the vapour that returns to the compressor 4, thereby enhancing the efficiency of the system.

[0026] A cooling appliance 1 according to this embodiment is obtained, the cooling system of which is partially no-frost, as the freezer compartment 2 is cooled by means of a no-frost evaporator 7, with the assistance of a fan, by forced-air circulation, and the refrigeration compartment 3 is cooled by means of a static evaporator 6 by natural convection. This no-frost evaporator 7 does not allow frost to accumulate in the freezer compartment 2, on the food, or in the evaporator.

[0027] This cooling appliance 1 is also disposed with a single temperature regulator 8 attached to a temperature sensor 10 disposed in the refrigeration compartment 3, which unlike cooling appliances disposed with a single temperature sensor disposed in thermal contact with the evaporator, operates more precisely and reliably. Cooling appliances disposed with two temperature sensors, one in thermal contact with the evaporator and another in the refrigeration compartment, perform, along with the first sensor, the defrosting of the evaporator, and with the second, the operating of the cooling appliance, but are more complex than the cooling appliance 1 of the invention, which performs the defrosting of the static evaporator 6 by means of a periodic programming of a cycle with a temperature Ton with a higher value than that corresponding to the set value selected. All this results in a lower cost, as efficiency is improved in terms of operation, this being achieved with a smaller number of components.

[0028] The cooling appliance 1 of the invention is a simpler cooling appliance than a cooling appliance with two regulators, regardless of whether it is static or no-frost. It is an appliance that has a capillary, does not have an electric valve, and the control unit is simpler as it has to control less components and functions. This also involves a reduction in costs in relation to appliances with two regulators due to the lower number of components and the fact it is simpler.

[0029] Finally, and in terms of quality, in the process for manufacturing the cooling appliance 1 an improvement is achieved due to the increased simplicity of the components to be assembled and in a smaller quantity, thereby reducing the possibility of mistakes being made and an incorrect assembly, thereby reducing the number of welds and, therefore, the probability of the refrigeration agent leaking. As a result of all this, the product quality perceived by the user is greater.

Claims

1. Cooling appliance (1) with a freezer compartment (2) and at least one refrigeration compartment (3), which comprises:

a compressor (4);

a condenser (5); and

at least two cooling units associated to the freezer (2) and refrigeration compartments (3) and connected in series, situated in a refrigeration-agent circuit (9),

characterised in that the cooling unit of the refrigeration compartment is a static evaporator (6), the cooling unit of the freezer compartment is a no-frost evaporator (7), and the cooling appliance (1) comprises a single temperature regulator (8).

2. Cooling appliance (1) according to claim 1, wherein there is a temperature sensor (10) associated with the regulator (8), said temperature sensor (10) being arranged in the refrigeration compartment (3).

3. Cooling appliance (1) according to claim 2, comprising a temperature selector switch (12) associated to the regulator (8).

4. Cooling appliance (1) according to claim 3, wherein the regulator (8) switches on the circuit (9) if the temperature measured by the sensor (10) is higher than an upper threshold temperature Ton corresponding to the temperature set point selected by means of the temperature selector switch (12), and switches off said circuit (9) if the temperature measured by the sensor (10) is lower than a lower threshold temperature Toff corresponding to said temperature set point.

5. Cooling appliance (1) according to claim 4, wherein the regulator (8) periodically programmes a cycle with an upper threshold temperature Ton higher than that corresponding to the temperature set point, in order to defrost the static evaporator (6).

6. Cooling appliance (1) according to any of the preceding claims, comprising a safety temperature sensor (11) in the freezer compartment (2) connected to the regulator (8).

7. Cooling appliance (1) according to any of the preceding claims, wherein the evaporator of the refrigeration compartment (6) is fluidly connected next to the evaporator of the freezer compartment (7).

Drawing