ES2373135A1 - Household appliance comprising an expansion system - Google Patents

Abstract

The invention relates to a household appliance (1) comprising a treatment chamber (2) for treating articles (3), a process air guide (5) for guiding process air through said treatment chamber (2), said process air guide (5) comprising a blower (6) for driving the process air, a heater (7) for heating the process air and placed upstream of said treatment chamber (2), and a heat pump (7, 8, 9, 10, 11), wherein said heater (7) is a heat source (7) for transferring heat from a refrigerant circulating through said heat pump (7, 8, 9, 10, 11) to the process air, and wherein said heat pump (7, 8, 9, 10, 11) further comprises a heat sink (8) for transferring heat into the refrigerant, a compressor (9) for compressing the refrigerant, an expansion system (10) for expanding the refrigerant, and a refrigerant guide (11) for circulating the refrigerant through said heat pump (7, 8, 9, 10, 11) in a closed circuit. Said expansion system (10) has a variable restriction which may be controllable by a control unit (14) in response to signals from a sensor unit (15, 16).

Description

Domestic appliance comprising a system of expansion.

The invention relates to a household appliance comprising a treatment chamber for treating articles, a process air guide to guide process air through said treatment chamber, said air guide comprising the process a blower to drive process air, a heater to heat the process air and placed upstream of said treatment chamber, and a heat pump, where said heater is a source of heat to transfer heat from a refrigerant circulating through said air heat pump of the process, and where said heat pump further comprises a heatsink to transfer heat to the coolant, a compressor to compress the refrigerant, an expansion system to expand the refrigerant, and a refrigerant guide for circulating the refrigerant through said heat pump in a closed circuit.

A household appliance of this generic type is disclosed in WO 2008/107266 A1. The disclosed apparatus is a dryer of domestic clothes whose heat pump is a heat pump of the type of compressor, which is characterized by having a refrigerant that It is guided in a closed refrigerant guide. To make a heat absorption to the associated heatsink, the refrigerant It is made to evaporate in the heatsink and, to release heat from the associated heat source, the refrigerant is made to liquefy in the heat source. To carry out the transport of heat and that evaporation and liquefaction processes take place at appropriate temperatures, the gaseous refrigerant is compressed when it passes from the heat sink to the heat source, and the Liquid refrigerant is expanded in an expansion system when returns from the heat source to the heat sink. According to the aforementioned document, a special selection of the compressor is made comprised of heat pump and coolant.

In WO 2008/119611 A1, a cleaning device to clean a heat sink from a Heat pump of a clothes dryer. A heat sink in a clothes dryer is subject to degradation by operation through small materials formed of particles that comprise fiber fragments and the like, usually called yarn or lint, and removed from the laundry that is air dried of process. In accordance with usual practice, a filter lint is placed in the air guide of the running process above the heatsink to capture a large part of the process air fluff. Even so, a small fraction, but considerable, the fluff will avoid being captured by the filter fluff, and will precipitate on the heatsink along with condensate formed from the moisture contained in the air of the process, which is formed by extracting heat from the air in the process.

While each of the two documents cited above is relative to a household appliance that has a guide of process air, which is essentially closed in itself to guide the process air in an essentially closed circuit, WO 2008/110449 A1 discloses a household appliance that has a pump heat, and that has a process air guide, which is partially open.

In accordance with WO 2008/119608 A2 and WO 2008/086933 A1, a heat pump can be applied in a household appliance, in addition to electric or burner heaters of gas and most common air / air heat exchangers. Such appliances can be called "hybrids".

In accordance with WO 2007/141166 A1, the heat sink and heat source of a heat pump comprised of a domestic appliance can be arranged in a bifurcated process air guide, so that the process air passes through them as two-part flows in parallel, unlike the more usual practice that requires that the air flow of the undivided process pass through the heat sink and the heat source in
sequence.

To the extent that they are relative to applying a heat pump of the compressor type to a household appliance, and also in accordance with general practice with appliances domestic with compressor type heat pumps, since they are marketed at the time of establishing the right to priority to the invention disclosed below, the pumps of heat are equipped with components whose characteristics related to operation are fixed by sizing and construction Normal use of such household appliances will have place under a variety of environmental conditions defined by the location of devices and seasons. Also, the use normal in itself will also incur a variety of conditions of operation. For example, the operation of a dryer clothes with a heat pump will include an initial phase, where components of the appliance and the same washing clothes to be dried will be brought to their operating temperatures adequate, an almost stationary phase, in which the most of the drying operation, and a finishing phase, in the that the laundry is almost as dry as desired, and the Extraction of residual moisture from the laundry requires raise the process air temperature, which passes through the clothes of washing, above the level that had been continued throughout The almost stationary phase. Consequently, a heat pump structure that allows operation the heat pump through all these phases, while They also face variable environmental conditions.

An objective of the present invention is present a development of the apparatus as defined in the Preamble of this application, which overcomes the disadvantages specified.

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In order to comply with this and others objectives, a domestic appliance is specified in the claim independent attached. In the dependent claims and the further description are specified embodiments Preferred household appliances according to the present invention.

Therefore, it is specified, in accordance with the invention, a domestic appliance comprising a chamber of treatment to treat items, an air guide of the process for guide process air through said treatment chamber, said process air guide comprising a blower for conduct the process air, a heater to heat the air of the process and placed upstream of said chamber of treatment, and a heat pump, where said heater is a heat source to transfer heat from a circulating refrigerant through said heat pump to the process air, and where said heat pump further comprises a heat sink to transfer coolant heat, a compressor to compress the coolant, an expansion system to expand the refrigerant, and a guide for refrigerant to circulate the refrigerant through said pump of heat in a closed circuit. In addition, said expansion system It has a variable constraint.

According to the invention, an expansion system variable replaces known expansion systems with dimensional and constructive parameters set, to produce operating flexibility for the household appliance in view of adapt to the changing environment and requirements related to functioning.

An effective operating parameter of the expansion system is a restriction, which is measured as a decrease in the pressure generated by the liquid refrigerant flowing through at a nominal temperature and a nominal mass flow. In the case of an expansion system given by a single extender, different embodiments such as ejector or hole, on the one hand, and capillaries of different lengths and different diameters, on the other hand, may result in the same restriction. Therefore, the invention does not impose an a priori limitation on constructive details of the expansion system. It can be noted that variable expansion systems are known for non-relevant applications, such as refrigeration appliances.

The invention will allow a domestic appliance adapt to a variety of ambient temperatures, to ensure the proper operation at ambient temperatures that vary between 5ºC and 35 ° C, 23 ° C being a nominal temperature. Also, the changes in the operating parameters that occur through a process to treat items in the apparatus can be adapted, modifying the characteristics of the heat pump as given by restricting the expansion system, in order to adapt better the scheme and functional settings of the heat pump to relevant operating conditions and thus obtain a better operating efficiency and possibly a shorter duration of The treatment processes.

In accordance with an embodiment preferred of the invention, the household appliance comprises a unit of control connected to said expansion system, and a unit of sensor associated with said heat pump, to control the restriction of said expansion system in response to signals communicated to said control unit by said sensor unit. From that way, the expansion system can be controlled in response to relevant operating conditions of the heat pump. In order to allow and carry out such control, a plurality of options. As a first example, the expansion system may have a restriction that is controllable by means electronic In such a case, the control unit may be a autonomous electronic circuit, or it may be included in a unit of control of the system that carries out the global control of the device, even interact with a user to view operating information, select programs from operation to treat items placed in the apparatus, and set operating parameters for such programs.

In accordance with one more embodiment preferred of the invention, said sensor unit specified in the previous paragraph comprises a status sensor to perceive a state of said heat pump. Even more preferred, said status sensor is a temperature sensor to perceive a process temperature within said refrigerant guide. From even more preferred way, the process temperature is a coolant temperature when leaving said heatsink, and said control unit is preset to control said system expansion to retain a given overheating in the refrigerant leaving said heat sink. In this context, it should be noted that in the normal operation of the device, including the heatsink, where the refrigerant enters the heatsink in a liquid state, to be evaporated while flows through the heat sink to form a gas, such gas a certain amount will be heated to a temperature that is above of the boiling temperature of the refrigerant under the condition of given pressure. The difference in boiling temperature at gaseous refrigerant temperature when exiting the heatsink It is defined to be overheating. A heat pump, such and as it is known to be incorporated in a drying apparatus of clothing will not allow any control through normal use during A drying process Thus, overheating will change under changing operating conditions. Applying one provision as presented here, has made possible the overheating control, including control to retain the overheating at a certain and desired value.

In accordance with another embodiment preferred of the invention, said sensor unit comprises a ambient temperature sensor to perceive a temperature environment of said apparatus. This allows to take into account the relevant environmental conditions to put the apparatus, including the heat pump, and also allows the modification of the operating mode in response to conditions environmental. Since any heat pump will require a amount of energy input for its operation, which must be, in turn, dissipated to its surroundings, the ambient temperature is a functional parameter for the heat pump since it affects that dissipation. According to the invention, the ambient temperature can be considered when operating the heat pump. By way of more preferred in this regard, said control unit is preset to set said restriction to a nominal value if the ambient temperature is essentially equal to a temperature given normal environment, and where said control unit is preset to set said restriction to a value that exceeds said value nominal, if the ambient temperature is essentially different from said normal room temperature. A preferred setting for the operation may provide for fixing the expansion system in a normal restriction at a normal room temperature, which can be a usual room temperature that can be found in a normal household, and increase the restriction above the restriction normal, both at ambient temperatures above and below normal room temperature. When the room temperature is excessively high, a thermal load on the heat pump is high, and the compressor in the heat pump may incur a load unduly high thermal. Increasing the restriction, it will reduce a mass flow of the refrigerant that circulates through the heat pump, and simultaneously the load on the compressor. When the ambient temperature is excessively low, the Thermal load on the heat pump is low. On the other hand, it can it is difficult to determine the total evaporation of the refrigerant at flow this through the heatsink. Increasing the restriction and, thus, reducing the mass flow of the coolant in circulation, the introduction of liquid is reduced to evaporate in the heatsink, thereby mitigating the problem of determining total evaporation.

In accordance with another embodiment preferred of the invention, said expansion system comprises the minus two expansion units, which are gears of variable manner in said refrigerant guide by said unit of control. This allows to apply an expansion system, where a selection between several values set for the restriction is possible simply by switching. More preferably, said expansion system comprises an expansion unit, which comprises a first extender, and a valve controllable by said control unit and connected in series. More preferably, the expansion system can include a second extender connected in parallel to said expansion unit. Such embodiment ensures that a connection state that results cannot be produced in a complete disconnection of the expansion system, providing in this way a safety measure. Even more preferred, in the expansion system a plurality of expansion units connected in parallel to each other others, thereby providing an extended range of restriction variability, to improve the adaptability of the system to various requirements related to operation. By way of even more preferred, said expansion unit comprises a multiplicity of first extenders, where said first extenders are connected in parallel to each other through a multi-way distribution valve controllable by said control unit, thus simplifying the connection means, to the while maintaining a high level of variability.

In accordance with yet another embodiment preferred of the invention, said expansion system is a variable expansion device controllable by said unit of control. By way of preferred example, said expansion device It comprises a variable expansion valve. In particular, said expansion valve is a thermostatic expansion device. From even more preferred way, said expansion device thermostatic has an associated temperature sensor coupled to said process air guide at an outlet of said chamber of treatment to perceive an air temperature of the air of the process when leaving said treatment chamber, and where said thermostatic expansion device is planned to vary said restriction from a relatively low restriction to a air temperature drops to a relatively restricted raised to a high air temperature. Likewise preferred, said expansion system is a multiplicity of thermostatic expansion devices, and where said devices thermostatic expansion are connected in parallel to each other through a multi-way distribution valve controllable by said control unit.

According to the invention, valves are preferred variables for use as expansion units, although they can require to provide an electronic control, which can be a unit autonomous or a part of an electronic control unit of the system as explained here above. In addition, you can apply a variable expansion device that is marketed as an autonomous unit, which includes sensor and control means, to vary a restriction in response to a state variable, which is, in general, a temperature, as perceived by The sensor means. In this regard, the sensor means can be applied as a status sensor or temperature sensor environment, as explained here above. Likewise, other control modes can be implemented using such variable expansion device. As a precaution, it should be noted that the term "thermostatic expansion device" is known to an expert in the field, due to the application of such devices in self-regulated refrigeration circuits in freezers or refrigerators. In addition, the relative property to be "thermostatic" is not really a device property of expansion itself but of the complete cooling circuit that include the device

As an example, a process of typical drying as performed in a drying apparatus of common clothes. Immediately after commissioning, the drying process will begin with the heating phase, in the that the components included in the process air circuit their temperatures will change to operating values, and the items to be dried will be heated to a temperature of high performance. To keep the duration of the process, it is desired to keep the heating phase short. By consequently, a relatively high restriction is desired in the expansion system to reach a relatively high pressure of the refrigerant in the heat source leading to a condensing temperature of coolant high, at a high temperature difference between refrigerant and air from the process at the heat source, and to a heat transfer to the process air increased, accordingly. Also, the flow of Highly restricted refrigerant will reduce the amount to be be evaporated in the heatsink, and also the cooling resulting from the process air in the heatsink. As soon as the components have reached their respective temperatures of operation, an almost stationary phase will follow the phase of heating. In the almost stationary phase, they will only occur small changes in operating temperatures, and the expansion system restriction can be set to a value reduced nominal (which may still be dependent on environmental conditions as explained here above). When the drying process is nearing its end, all moisture has been evaporated from the surfaces of the items to be dried, and the remaining moisture must be extracted from deep within the textile fibers that constitute the articles. This provides an additional burden on the process, which manifests itself in another increase in the operating temperature of the articles, the components in your environment and the process air that It flows from them. This temperature rise indicates a transition from the almost stationary phase to a terminal phase of the process of dried In general, this phase is short with little influence on the Duration of the whole drying process. In addition, it would be desirable an increased restriction to reduce the evaporation temperature of the refrigerant in the heatsink, and improve the extraction of process air humidity. Therefore, and disregarding the Desires for the finishing phase specified above, a device of autonomous variable expansion, or a plurality of such devices, in particular, selectable through valve distribution in response to environmental conditions, can be applied in the inventive apparatus for such purpose. The function of such a device would reduce the restriction in case of increased temperature. If they also had to take into account the particular requirements for the terminal phase, the addition of a switchable extender made as indicated here previously.

In accordance with yet another embodiment preferred of the invention, said process air guide within the inventive apparatus is essentially closed in itself to guide the process air in an essentially closed circuit, the apparatus thus providing a circuit dryer closed or dryer condensation type.

In accordance with yet another embodiment preferred of the invention, said heatsink is a cooler placed in said process air guide to cool the air of the process after exiting said treatment chamber to remove the humidity of said process air, again in accordance with the Features of a condenser dryer. More way preferred, said cooler has a condensate collector placed below it to collect condensate from the air of the process inside said cooler, to collect the extracted moisture of items operating the device inventive.

In accordance with yet another embodiment preferred of the invention, said treatment chamber is a drum rotary to stir the items placed in it to treatment.

Other details and advantages of the invention are extract from the following description of embodiments preferred, which are also shown in the figures of the drawing attached. In particular:

Figure 1 shows a household appliance, such and as it materializes in a clothes dryer, and with a device expansion with variable restriction;

Figure 2 shows a first form of realization of an expansion device, which has a variable restriction;

Figure 3 shows a second form of realization of an expansion device, which has a variable restriction; Y

Figure 4 as a variable expansion device built into an expansion device with a restriction variable.

In the drawing, figure 1 shows an apparatus domestic 1 which is incorporated as a clothes dryer 1. The clothes dryer 1 comprises a treatment chamber 2, which It is configured as drum 2, where items 3 are placed that have to be dried, in this case, the laundry clothes 3. Details and accessories, such as a door and a drive mechanism, as they are commonly associated with such drum 2, they are not shown for simplicity. The drum 2 is rotary around an axis 4 to stir the laundry clothes 3 through process air flowing along to extract the moisture of laundry garments 3. The process air for Dry laundry clothes 3 is guided by an air guide of process 5. The air guide of process 5 comprises a blower 6, which conducts process air in a circuit essentially closed. In this regard, "essentially closed" means that process air guide 5 is maintained at a pressure essentially equal to the pressure of the environment of the apparatus 1, but not It is tightly sealed against the surroundings, although without leakage some functionally relevant, by means of which would exchange air between the process air guide 5 and the environment. The process air guide 5 includes a heater 7, or heat source 7, placed upstream of drum 2 to heat the process air before entering the drum 2. Current below the drum 2, the process air guide 5 includes a cooler 8 or heatsink 8, where heat is extracted from the air of the process after leaving the drum 2. The process air guide 5 may include other components in accordance with practice habitual. In particular, sensors may be present temperature and a lint filter, but not shown in the figure 1 for simplicity.

The heat source 7 and the heat sink 8 are made as heat exchangers 7 and 8 for exchange heat with the air of the process that passes through. The heat source 7 and heatsink 8 are also included in a heat pump 7, 8, 9, 10, 11. This provides for heat recovery extracted from process air in heat sink 8 by pumping said heat to heat source 7, where it is transferred back to the air of the process. While such a heat pump process It cannot work by itself, but necessarily requires an introduction of additional energy to be effective, just as provide for the laws of thermodynamics, such a process greatly reduces measure the energy input required to evaporate all moisture of laundry clothes 3 contained in drum 3. The heat pump 7, 8, 9, 10, 11 includes, in addition to the heat source 7 and the heatsink 8, a compressor 9 to compress a refrigerant that is circulated through the heat pump 7, 8, 9, 10, 11 in a closed circuit, an expansion system 10 for carry out an internal pressure reduction within the circulating refrigerant, and a refrigerant guide 11, which guides the refrigerant while it is circulating. The refrigerant can be selected from a variety of chemical compounds and compositions, whose aptitude for the purpose is known in the art. In in particular, the refrigerant can be a hydrocarbon compound, such as propane (R290 in terms of those commonly employed ASHRAE standards), a fluorinated hydrocarbon compound, such as R134a and R152a, or a mixture of such hydrocarbon compounds fluorinated, such as R407C and R410A; the compounds are indicated in terms of the commonly used ASHRAE standards. At operation, the refrigerant will leave the heatsink 8 in gaseous form, to be guided to the compressor 9 by the guide refrigerant 11. The compressor 9 will compress the refrigerant gas, and send it to heat source 7. In heat source 7, the refrigerant will release heat to the air from the process that flows through and, consequently, it will condense into a liquid form. After leaving the heat source 7, the liquid refrigerant passes through the system expansion 10, which is configured, in a known manner, as a choke or restriction. The most common device form that can be used as an expansion system 10 is a capillary 10, that is, a tube of considerable length with a section Very small cross section. The expansion system 10 serves to Reduce the internal pressure of the liquid refrigerant. Then, the refrigerant enters the heat sink 8 in liquid form, and It will absorb heat from the process air flowing through. The heat absorbed in the liquid refrigerant will cause the refrigerant to evaporate in a gaseous form, thus completing a complete cycle of circulation. Due to differences in the internal pressure of the refrigerant between heat source 7 and heatsink 8, the refrigerant condensation will take place at a temperature considerably greater than its evaporation, as a prerequisite for the heat pump process used to put in clothes dryer operation 1.

Moisture extraction from clothing Wash 3 is performed by process air, and moisture collected by the process air will be extracted from the process air in the heatsink 8. There, the heat is extracted from the air in the process, causing the moisture contained in it in the form of steam condenses and forms a condensate, which precipitates from The process air. This condensate is collected in a line of condensate 12, and transported to condensate collector 13. After completion of a drying process, condensate collector 13 can be emptied, and the condensate discarded in any way appropriate.

A special feature of the device shown in figure 1 is that the expansion system 10 has a defined constraint to determine the magnitude of flow of a pressure condensate and given temperature conditions, which is variable by operating a control unit 14 specific. For this purpose, the control unit 14 is connected to a sensor unit 15, 16, comprising a status sensor 15 to determine a coolant temperature when it leaves the heatsink 8, and a room temperature sensor 16, the which determines a temperature around the apparatus 1. From conformance with the signals obtained from these sensors 15 and 16, the control unit 14 will set the restriction of the expansion system 10 to vary the operating conditions of the pump heat 7, 8, 9, 10, 11 in response to these signals.

The expansion system 10 with its restriction variable allows device 1 to adapt to a variety of ambient temperatures, to ensure proper operation at ambient temperatures that vary between 5ºC and 35ºC, being 23ºC a nominal temperature Also, changes in the parameters of operation that occur through a process to deal with the articles 3 in the apparatus 1 can be adapted, modifying characteristics of the heat pump 6, 7, 8, 9, 10, 11 as they are given by the restriction of the expansion system 10, to adapt better the scheme and functional settings of heat pump 6, 7, 8, 9, 10, 11 to relevant operating conditions and, thus, obtain better operating efficiency and possibly a shorter duration of treatment processes.

The status sensor 15 is a sensor temperature 15 to perceive a process temperature within the refrigerant guide 11. The process temperature is a coolant temperature when leaving heat sink 8, and the control unit 14 is preset to control the system expansion 10, to retain a given overheating in the refrigerant leaving the heat sink 8. In this context, it has it should be noted that in normal operation of the device 1, including the heatsink 8, where the refrigerant enters the heatsink thermal 8 in a liquid state, to be evaporated while flowing to through the heat sink 8 to form a gas, such gas will be heated a certain amount to a temperature that is above the boiling temperature of the refrigerant under the condition of given pressure The difference in boiling temperature at gaseous refrigerant temperature when exiting the heatsink 8 is defined to be overheating. Generally the overheating will change under operating conditions changing. Applying a provision as presented here, overheating control is possible, including control to retain overheating at a given and desired value.

In addition, the sensor unit 15, 16 comprises the 16 room temperature sensor to perceive a temperature device environment 1. This allows for the conditions to be taken into account environmental conditions to operate the device 1, including heat pump 6, 7, 8, 9, 10, 11, and also allows the modification of the operating mode in response to conditions environmental. Since the heat pump 6, 7, 8, 9, 10, 11 necessarily requires an amount of energy input for your operation, which must be, in turn, dissipated from its surroundings, the ambient temperature is a functional parameter for the operation, since it affects that dissipation. In this case, the room temperature can be considered when putting in heat pump operation 6, 7, 8, 9, 10, fixing the restriction on the expansion device 10. In particular, the control unit 14 is preset to set the restriction on a nominal value if the ambient temperature is essentially equal to a given normal room temperature, and control unit 14 is preset to set said restriction to a value that exceeds said nominal value, if the ambient temperature is essentially different of said normal ambient temperature. A preferred setting for the operation may provide for fixing expansion system 10 in a normal restriction at a normal room temperature, which can be a usual room temperature that can be found in a normal household, and increase the restriction above the restriction normal, both at ambient temperatures above and below normal room temperature. When the room temperature is excessively high, a thermal load on the heat pump 6, 7, 8, 9, 10, 11 is high, and the compressor 9 may incur a load unduly high thermal. Increasing the restriction, it will reduce a mass flow of the refrigerant that circulates through the heat pump 6, 7, 8, 9, 10, 11, and simultaneously will be reduced the load on the compressor 9. When the ambient temperature is excessively low, the thermal load on the heat pump 6, 7, 8, 9, 10, 11 is low. On the other hand, it can be difficult to determine the Total evaporation of the refrigerant when it flows through the heatsink 8. Increasing the restriction and, thus, reducing the mass flow of the refrigerant in circulation, reduces the introduction of liquid to evaporate in the heatsink 8, thus mitigating the problem of determining the total evaporation.

In reference to the constructive details of the expansion system 10 and control unit 14, practice common, as is known to those skilled in the art, It provides numerous options. For example, the expansion system 10 may be performed as a valve 10, whose restriction may be varied continuously by electronic means. In that case, the control unit 14 could be an electronic circuit, which could function independently of other components of the apparatus 1, or, alternatively, be incorporated in a unit device control electronics 17, which is commonly used both for the control of the operation of the apparatus 1, and for interact with a user or operator by viewing information related to the process and reception through means of adequate input, control information to select a program for a predefined drying process or setting a parameter related to such a program. For simplicity, I don't know show display or input media. Common practice it also provides autonomous units that include a system of expansion 10 and a control unit 14, for example, in the form of a "thermostatic expansion device", which is Commonly used in freezers and refrigerators.

Figure 2 shows an example of a system of expansion 10, which comprises two expansion units 18, 19, each of which comprises a first extender 18, possibly a capillary 18, and a switching valve 19 connected in series. Both expansion units 18, 19 are connected in parallel, and a second extender 20 is connected in parallel to both units 18, 19. Both switching valves 19 can be switched from closed to open by the unit of control 14, thus providing a total of four restrictions different available to define operating parameters for heat pump 7, 8, 9, 10, 11 as exemplified in figure 1.

Figure 3 shows an expansion system 10 alternative for use in coolant guide 11 between source of heat 7 and the heatsink 8. Again, the system of expansion 10 comprises expansion units 18, each constituted from a single extender 18, and all extenders 18 connected to a distribution valve 21 controllable by the control unit 14, which can selectively activate each of the extenders 18 for use in the heat pump 7, 8, 9, 10, 11 as exemplified in figure 1.

Figure 4 shows another example of a system variable expansion 10 incorporated in an expansion device thermostatic This device includes a variable valve continuous way 10 included in the refrigerant guide 11. Also, includes a process air temperature sensor 22, which is connected in this case to the air guide of process 5 to perceive a process air temperature when it leaves the treatment chamber 2. Here, the air temperature sensor of the process 22 is simply a bulb, which is filled with a working fluid 24 that will serve to perceive a temperature at That is exposed. In principle, the temperature sensor 22 can be placed in any location deemed useful for your operation to control the variable valve 10. The sensor temperature 22 is connected to a chamber 14 that serves as a unit control 14. Inside chamber 14, a movable diaphragm 23 separates a space filled by the working fluid, and that communicates with the inside of bulb 22, of a part of the space filled by air. Diaphragm 23 contacts a push bar 25, which, in turn, it serves to set the restriction of the variable valve 10. When the process air temperature at the drum outlet 2, and perceived by bulb 22, change, working fluid 24 expand or contract and move diaphragm 23 so correspondent. This movement is transmitted to the valve variable 10 by the push bar 25, and will cause a change in the variable valve restriction 10 in response to a change in the process air temperature. In this way, a adaptation of heat pump operation 7, 8, 9, 10, 11 in response to the process air temperature at the outlet of the drum 2.

Immediately after putting on operation, the typical drying process executed in the appliance drying 1 will begin with the heating phase, in which the components included in the process air circuit 2, 5, 6, 7, 8 will change your ambient temperature temperatures to values of operation, and 3 items to be dried will be heated to a high operating temperature. For keep the duration of the process short, you want to keep the heating phase Therefore, a restriction is set relatively high in expansion system 10 to achieve a relatively high pressure of the refrigerant at the source of heat 7 leading to a condensing temperature of high refrigerant, at a high temperature difference between the refrigerant and the process air in the heat source 7, and a an increased heat transfer to the process air, in consequence. Also, the refrigerant flow highly restricted will reduce the amount to be evaporated in the heatsink 8, and also the resulting cooling of the air of the process in the heatsink 8. As soon as the components 2, 5, 6, 7, 8 have reached their respective operating temperatures, an almost stationary phase will follow the heating phase in the drying process. In the phase almost stationary, only small changes will occur in the operating temperatures, and system restriction of expansion 10 can be set at a reduced nominal value (which it can still be dependent on environmental conditions as it has explained here before). When the drying process is nearing its end, all moisture has been evaporated from surfaces of items 3 to be dried, and moisture remaining must be extracted from deep within the fibers textiles that constitute articles 3. This brings a burden additional on the process, which manifests itself in another increase in operating temperature of items 3, the components 2 in their environment, and the process air flowing from them. This temperature rise indicates a phase transition almost stationary to a terminal phase of the drying process. In general, this phase is brief with little influence on the duration of the process of dried together. In addition, an increased restriction would be desirable. to reduce the evaporation temperature of the refrigerant in the heatsink 8, and improve the extraction of moisture from the air of the process. Therefore, and disregarding the wishes for the phase Finishing specified above, an expansion device autonomous variable 10, or a plurality of such devices 10, in particular, select through distribution valve 21 in response to environmental conditions, can be applied in the apparatus 1 for such purpose. The function of such device 10 would be reduce the restriction in case of temperature increase. Yes the particular requirements also had to be taken into account for the terminal phase, the addition of an extender may be effective switchable as shown in figure 4.

In relation to the process air guide 5 inside the apparatus 1 detailed here, it is essentially closed in itself to guide the process air in a circuit essentially closed, thereby providing the apparatus 1 with a dryer closed circuit or condenser type dryer. Also this It should not be considered as a mandatory feature. The novel features disclosed here will be provided in a good way for another type of apparatus, where the process air guide 5 does not is essentially closed in itself, or where they are even implemented multiple 5 process air circuits, so parallel to each other.

Finally, it turns out that the present invention, as defined in the appended claims, and as detailed and exemplified here before, enables novel embodiments of a household appliance, in particular, a clothes dryer, and a contained heat pump in it, to further improve effectiveness and duration of the treatment processes programmed for use in such apparatus.

List of reference numbers

one

Domestic appliance, clothes dryer

2

Treatment chamber, drum

3

Items to be dried, clothes of washed

4

Axis of rotation

5

Process air guide

6

Blower

7

Heater, heat source

8

Cooler, heatsink

9

Compressor

10

Expansion system

eleven

Refrigerant Guide

12

Condensate line

13

Condensate collector

14

System control unit expansion

fifteen

Status sensor, temperature sensor refrigerant

16

Room temperature sensor

17

Device control unit

18

First extender

19

Switching valve

twenty

Second extender

twenty-one

Distribution valve

22

Air temperature sensor process

2. 3

Diaphragm

24

Working fluid

25

Push bar.

Claims (21)

1. Household appliance (1) comprising a treatment chamber (2) for treating articles (3), a process air guide (5) for guiding process air through said treatment chamber (2), said treatment comprising process air guide (5) a blower (6) to drive the process air, a heater (7) to heat the process air and placed upstream of said treatment chamber (2), and a heat pump ( 7, 8, 9, 10, 11), wherein said heater (7) is a heat source (7) for transferring heat from a refrigerant that circulates through said heat pump (7, 8, 9, 10, 11 ) to the process air, and wherein said heat pump (7, 8, 9, 10, 11) further comprises a heat sink (8) to transfer heat to the refrigerant, a compressor (9) to compress the refrigerant, a system of expansion (10) to expand the refrigerant, and a refrigerant guide (11) to circulate the refrigerant through said heat pump (7, 8, 9, 10, 11) in a closed circuit, characterized in that said expansion system (10) has a variable restriction. 2. Domestic appliance according to claim 1, comprising a control unit (14) connected to said system of expansion (10), and a sensor unit (15, 16) associated with said heat pump (7, 8, 9, 10, 11) to control the restriction of said expansion system (10) in response to signals communicated to said control unit (14) by said sensor unit (15, 16). 3. Domestic appliance (1) according to claim 2, wherein said sensor unit (15, 16) comprises a sensor of state (15) to perceive a state of said heat pump (7, 8, 9, 10, 11). 4. Domestic appliance according to claim 3, wherein said status sensor (15) is a temperature sensor (15) to perceive a process temperature within said guide of the refrigerant (11). 5. Domestic appliance according to claim 4, where the process temperature is a coolant temperature when leaving said heatsink (8), and where said unit of control (14) is preset to control said system of expansion (10) to retain a given overheating in the refrigerant leaving said heat sink (8). 6. Domestic appliance (1) according to one of the claims 2 to 5, wherein said sensor unit (15, 16) comprises an ambient temperature sensor (16) to perceive a ambient temperature of said apparatus (1). 7. Domestic appliance (1) according to claim 6, wherein said control unit (14) is preset to set said restriction at a nominal value, if the ambient temperature is essentially equal to a given normal room temperature, and where said control unit (14) is preset to fix said restriction on a value that exceeds said nominal value, if the ambient temperature is essentially different from that temperature normal environment. 8. Domestic appliance (1) according to one of the claims set forth above, wherein said system of expansion (10) comprises at least two expansion units (18, 19, 21), which are variable gears in said guide of the refrigerant (11) by said control unit (14). 9. Household appliance (1) according to claim 8, wherein said expansion system (10) comprises a unit of expansion (18, 19, 21), which comprises a first extender (18) and a valve (19) controllable by said control unit (14) and connected in series. 10. Domestic appliance (1) according to claim 9, comprising a second extender (20) connected in parallel to said expansion unit (18, 19, 21). 11. Domestic appliance (1) according to one of the claims 9 and 10, comprising a plurality of units of expansion (18, 19, 21) connected in parallel to each other. 12. Domestic appliance (1) according to one of the claims 9 and 10, wherein said expansion unit (18, 19, 21) comprises a multiplicity of first extenders (18), where said first extenders (18) are connected in parallel to each other others through a multi-way distribution valve (21) controllable by said control unit (14). 13. Domestic appliance (1) according to one of the claims 1 to 7, wherein said expansion system (10) is a variable expansion device (10) controllable by said unit control (14). 14. Domestic appliance (1) according to claim 13, wherein said expansion system (10) comprises a variable expansion valve (10). 15. Domestic appliance (1) according to one of the claims 13 and 14, wherein said expansion valve (10) is a thermostatic expansion device (10). 16. Domestic appliance according to claim 15, wherein said thermostatic expansion device (10) has a associated temperature sensor (22) coupled to said air guide of the process (5) at an outlet of said treatment chamber (2) to perceive an air temperature of the process air when leaving of said treatment chamber (2), and where said device of thermostatic expansion (10) is intended to vary said restriction from a relatively low restriction to a air temperature drops to a relatively restricted raised to a high air temperature. 17. Domestic appliance (1) according to one of the claims 13 to 16, wherein said expansion system (10) is a multiplicity of thermostatic expansion devices (10), and where said thermostatic expansion devices (10) are connected in parallel to each other through a valve multi-track distribution (21) controllable by said unit of control (14). 18. Domestic appliance (1) according to one of the claims set forth above, wherein said air guide of the process (5) is essentially closed in itself. 19. Domestic appliance (1) according to claim 17, wherein said heatsink (8) is a cooler (8) placed in said process air guide (5) to cool the process air after leaving said treatment chamber to extract moisture from said process air. 20. Domestic appliance according to claim 19, wherein said cooler (8) has a condensate collector (13) placed under it to collect condensate that precipitates from process air inside said cooler (8). 21. Domestic appliance (1) according to one of the claims set forth above, wherein said chamber of treatment (2) is a rotating drum (2) to stir the items (3) placed in it for treatment.