WO2014040904A2

WO2014040904A2 - Condenser dryer with means for determining the loading, and method for operating the same

Info

Publication number: WO2014040904A2
Application number: PCT/EP2013/068363
Authority: WO
Inventors: Andrea GÄRTLEIN; Anja Hähnel; Marcus Simon
Original assignee: BSH Bosch und Siemens Hausgeräte GmbH
Priority date: 2012-09-14
Filing date: 2013-09-05
Publication date: 2014-03-20
Also published as: DE102012216397A1; EP2895652A2; CN104619906A; PL2895652T3; CN104619906B; EP2895652B1; WO2014040904A3

Abstract

The invention relates to a condenser dryer (1) having a process‑air channel (2), a drum (3) for accommodating items of laundry, a heat exchanger (5, 15) for condensing water from humid/warm process air, a control device 10, at least one temperature sensor (27, 28, 29, 30) and a means (11, 20, 32) for determining the quantity of water condensed in the heat exchanger, wherein the at least one temperature sensor (27, 28, 29, 30) is arranged in a cooling‑medium channel (24) and/or in the process‑air channel (2) and the control device (10) is intended to determine loading of the drum (3) with items of laundry with reference to progression over time of the temperature measured by the at least one temperature sensor (27, 28, 29, 30) and progression over time of the quantity of water condensed. The invention also relates to a method which is suitable for operating said dryer.

Description

Condensation dryer with determination of the load and method for its operation

The invention relates to a condensation dryer (hereinafter also abbreviated to "dryer") with a determination of the load of laundry items (hereinafter also abbreviated to "loading" or "loading quantity") and to a method suitable for operating this dryer Condensation dryer with a process air duct, a drum for receiving laundry, a heat exchanger for condensing water from moist, warm process air, a control device, at least one temperature sensor and a device for determining the amount of condensed water in the heat exchanger (hereinafter also referred to as "condensate") ,

Condensation dryers, whose operation is based on the condensation of the moisture vaporized by means of warm process air from laundry items, do not require an exhaust hose and are very popular because they can be used in internal bathrooms or laundry rooms of larger residential complexes. In the case of condensation dryers, the air (so-called "process air") moves in a largely closed circuit.The initially cool process air is generally passed through a fan by a fan, then the dry-warm process air enters the drum as a drying chamber In the drum, the hot process air absorbs the moisture from the laundry items, and the moist process air is passed from the drum to a heat exchanger for dehumidification, whereby the heat exchanger is usually an air-to-air heat exchanger The hot and humid process air is cooled in it, so that the water contained in it condense.The condensed water is then usually collected in a suitable receptacle and the cooled and dried air again the heating and then the Drum supplied.

During the individual drying phases, different loading quantities behave differently, so that it makes sense to adapt the drying process to the loading quantity. If, on the other hand, the drying phase of a dryer is For example, at lower loadings, the laundry is regularly "overdried" and thus unnecessarily consumes energy, and the drying process of the laundry lasts too long, which can be overcome by determining the load It also reduces energy consumption and thus protects the environment and saves the user costs.

DE 10 2008 025 496 A1 describes a measuring arrangement for determining information about the current loading of a tumble drier, wherein, instead of the ohmic conductance, the weighted electrical admittance of an electrode arrangement is used to gather information.

DE 10 2008 021 598 A1 describes a laundry drying apparatus and a method for its control, wherein a control unit in the laundry drying apparatus is adapted to control the drying operation on the basis of sensor data of a loading sensor. In the method, the loading weight is detected by means of the loading sensor. DE 10 2009 001 1 12 A1 describes a method for monitoring a loading of a laundry drum of a tumble dryer and / or for monitoring a degree of drying of laundry items introduced into the laundry drum, wherein the laundry drum is driven by means of an electric motor. In this case, depending on measured values of the current, the degree of drying of the items of laundry and / or the loading of the drum is concluded.

Finally, DE 10 2009 028 358 A1 describes a laundry treatment appliance with a rotatably mounted drum for drying and / or washing laundry, in which also electrical parameters of an electric motor are used for determining the mass of the laundry introduced into the drum.

DE 42 43 594 C2 discloses a method in which a load of laundry items is determined on the basis of a temperature change of the process air and a moisture value of the process air. This is the temperature change determined by a temperature sensor arranged in the process air flow at the outlet opening of the drum over a certain period of time. In addition, the humidity of the air discharged from the drum is measured by means of a humidity sensor. Then, a laundry quantity is determined by taking the absolute sum of the temperature change and the humidity value and dividing by two. Based on this amount of laundry, the amount of laundry is determined as a small, large or very large amount of laundry. This method uses the ambient temperature dependent quantity with the humidity value, but the ambient temperature is neglected, resulting in inaccuracies.

DE 10 2006 037 239 A1 describes a method and a tumble dryer for controlling the drying of wet laundry. In this case, a drying process is completed taking into account at least one moisture value or a corresponding measured value of the laundry to be dried, wherein additionally determined during drying of the laundry at or after reaching a predetermined moisture value or a corresponding measured value, the respective type of laundry and / or the respective load condition the laundry drum corresponding temperature size is used for targeted termination of drying.

DE 44 1 1 958 A1 describes a household tumble dryer with an electronic program control device and a rotatably mounted laundry drum and a fan for conveying the passing of a radiator over drying air through the laundry drum, wherein the time increase of the electrical resistance of the material to be dried and the temperature difference be detected and evaluated from drum inlet and drum outlet temperature. With the help of an electronic device conclusions are drawn to the type of laundry and the laundry weight of the material to be dried and the data obtained in this way are supplied as control variables for the further flow control of the selected drying program of the program control device.

DE 199 18 877 A1 describes a method for estimating the loading and / or the drying time in a household laundry dryer before the end of the drying process, in which a dependent on the laundry moisture size and a measure of the Temperature of an air stream for drying the laundry before and / or after its contact with the laundry is determined. The size dependent on the fabric moisture is used in conjunction with the measure of the temperature of the air stream before and / or after its contact with the laundry to estimate the loading and / or the drying time. In particular, a measure of the electrical resistance of the laundry is determined as the size dependent on the laundry moisture.

DE 199 39 274 A1 describes a method for determining the probable drying time of a drying process in tumble dryers with a continuous temperature detection at Trommelein- and drum outlet and moisture-controlled drying programs in which at least early after the start of the device uses at least two independent measures and correlated with each other be set. Examples of measured variables are the electrical resistance / conductance of the laundry at the beginning of the drying process, the temporal temperature profile at the drum outlet of the process air after switching on the heater and the respective mathematically / physically derivable variables, and several other variables related to the temperature.

Against this background, it was an object of the present invention to provide a condensation dryer (hereinafter also abbreviated to "dryer") with an improved determination of the load, the object of the invention being also to provide a method suitable for operating this dryer.

The solution of this object is achieved according to this invention by a condensation dryer and a method suitable for operating this dryer with the features of the corresponding independent patent claims. Preferred embodiments of the dryer according to the invention and of the method according to the invention are listed in the respective dependent claims. Preferred embodiments of the dryer according to the invention correspond to preferred embodiments of the method according to the invention and vice versa, although this is not explicitly stated herein. The invention thus relates to a condensation dryer with a process air duct, a drum for receiving laundry, a heat exchanger for condensing water from moist, warm process air, a control device, at least one temperature sensor and a device for determining the amount of condensed water in the heat exchanger, wherein the at least a temperature sensor is arranged in a cooling medium channel and / or in the process air channel and the control device is set up in order to use a time profile of the temperature measured with the at least one temperature sensor and a time profile of the amount of condensed water (hereinafter also referred to as "condensation rate"). designated) to determine a load of the drum with laundry.

Here, the loading is understood to mean the dry mass of the items of laundry to be dried introduced into the drum. According to the invention, at least one temperature sensor is used. If only one temperature sensor is used, in particular the time change of the temperature at the location of this temperature sensor is measured and used to determine the load. If more than one temperature sensor is used, it is also possible to measure the temperature difference between two locations, for example in the process air duct, and, in particular, also to track its temporal change. If in each case a temperature sensor is arranged both in the process air duct and in the cooling medium duct, the temperature in both ducts can be measured and their temporal change can be used to determine the load. Therefore, according to the invention, at least two temperature sensors are preferably used.

The type of temperature sensor is not limited, but an NTC sensor is preferred.

In a preferred embodiment of the condensation dryer, a first temperature sensor is arranged in the cooling medium channel at the entrance or exit of the heat exchanger for the cooling medium, preferably at the entrance. In a further preferred embodiment of the condensation dryer, a second temperature sensor is arranged in the cooling medium channel at the outlet of the heat exchanger for the cooling medium. The condensation dryer according to the invention furthermore generally has a heater, wherein this is in particular an electric heater or a gas heater, wherein an electric heater is preferably used. The heater serves to heat the process air before it is introduced into the drum of the condensation dryer. For conveying the process air, the condensation dryer also generally has a fan in the process air duct.

In the condensation dryer according to the invention, at least one heat exchanger for dehumidifying the moist, warm process air is present, so that the moist, warm process air from the drum is not conducted into an installation space of the dryer. Instead, at least some of the moisture from the moist, warm process air is removed by condensation. This is generally achieved by cooling the moist, warm process air. The heat exchanger generally uses a cooling medium, for example cooling air or a refrigerant, for dehumidifying the process air. The condensed water is then usually first collected in a condensate tray or pumped by a condensate pump, for example in a condensate tank.

The heat exchanger is in particular an air-air heat exchanger or a heat sink of a heat pump, in particular an evaporator. A heat pump is characterized by two heat exchangers, namely a heat sink, in which heat is absorbed, a heat source in which heat is released, and a pumping device, which transfers heat from the heat sink to the heat source optionally with a change in temperature. In a condensation dryer equipped with a heat pump of the compressor type, the cooling of the warm, moisture-laden process air essentially takes place in the heat sink of the heat pump, also referred to as evaporator, where the heat transferred to evaporate a refrigerant circulating in the pump device designed as a circuit is used. The refrigerant vaporized due to the heating is in the Pumping means via a compressor of the heat source, which is a condenser for the refrigerant supplied to the heat pump, where due to the liquefaction of the gaseous refrigerant heat is released, which is used to heat the process air before entering the drum. Behind the condenser, the now liquid refrigerant is expanded in a throttle of the pumping device, whereby its internal pressure is reduced, and finally passes back to the evaporator.

In the condensation dryer according to the invention is in the process air duct in any case preferably an air-to-air heat exchanger or an evaporator of a heat pump, particularly preferably an evaporator of a heat pump.

Preferably, in the air-air heat exchanger, a cooling air duct is provided, is passed through the air, in particular from a storage room of the dryer, as a cooling medium by means of a cooling air blower.

In the condensation dryer according to the invention, a time course of the amount of condensed water produced, ie condensate, measured and used to determine the load with laundry with. For this purpose, the condensation rate K describes the amount of water condensed out of the items of laundry to be dried, based on a specific period of time. Thus, for the condensation rate K:

Here, m _H 2o is the amount of the condensate obtained from the items to be dried water and At the corresponding period. According to the invention, the time period Δt is limited only to the extent that it must be sufficiently large in order to reliably determine the condensation rate K, wherein the respective minimum period At _min is generally dependent on the method for determining the condensation rate.

The amount of condensed water in the heat exchanger can be determined in different ways, and several methods of determination can be combined to improve accuracy. For this purpose, the fact is used that condensate generally in a first is collected below the heat exchanger arranged condensate tray. Then the amount of condensate in the condensate tray above the water level can be measured with the aid of a water level sensor. In a preferred embodiment of the condensation dryer, a water level sensor is therefore arranged in a condensate tray below the heat exchanger or in a condensate tank.

Usually, the condensate is pumped out for disposal or for intermediate storage in a condensate tank. For this purpose is located between condensate tray and condensate tank a condensate channel, in which a condensate pump is often arranged to convey the condensate. Alternatively, condensate can also be easily pumped into a sewer for disposal via the condensate duct. In any case, when using a condensate channel advantageously a flow sensor, which measures the amount of condensate flowing through, be used to determine the condensation rate. This is done with a direct disposal of the condensate, but also if the condensate is transported through the condensate channel for intermediate storage in the condensate tank.

When using water level or flow sensors, a comparatively small period of time can be selected, in which, depending on the sensor used still accurate readings are delivered, whereas when determined over a number of pump cycles of the pump used for pumping the condensate, the period At _min preferably should include at least two pump cycles. In this case, the entire period Δt is particularly advantageous in the main drying phase, with which Δ _max corresponds to the duration of the main drying phase. The main drying phase herein is the phase of the drying process, in which, at approximately constant process air temperature, the drying of the laundry mainly takes place.

The condensation dryer according to the invention is in particular a tumble dryer per se or a washer-dryer. A washer-dryer here is a combination device that has a washing function for washing laundry and a drying function for drying wet laundry. The dryer advantageously has an optical and / or acoustic display device for different states of the dryer. For this purpose, an optical display device is preferably used. By way of example, the display device can output information about the operation of the dryer by issuing a text or by illuminating different-colored light-emitting diodes, for example via the loading quantity or via a correspondingly adapted drying program or a remaining time of a drying program. The invention also provides a method for operating a condensation dryer with a process air duct, a drum with laundry items placed therein, a heat exchanger for condensing water from moist, warm process air, a control device, at least one temperature sensor and a device for determining the amount of water condensed in the heat exchanger in which the at least one temperature sensor is arranged in a cooling medium channel and / or in the process air channel and the control device is set up in order to load the drum with the items to be washed on the basis of a time profile of the temperature measured with the temperature sensor and a time profile of the amount of condensed water determine, wherein in the process for at least one predetermined time period At-i the time course of the measured temperature with the at least one temperature sensor and the time course of the amount of condensed water ermit Telt is and is determined by comparison with a deposited in the controller relationship between these time courses and the loading of the drum, a loading of the drum with laundry.

In this case, the loading is understood as meaning the dry mass of the items of laundry to be dried which are introduced into the drum and which do not change over the duration of the method according to the invention and in particular of a drying program carried out. A determination of the loading according to the invention is therefore necessary only once during the drying program, although it may possibly also take place more frequently.

The device for determining the amount of water condensed in the heat exchanger according to the invention is in particular a water level sensor in a condensate tray or a condensate tank, a flow sensor or a condensate pump, in particular one whose function depends on a minimum volume of condensate, so that the number of pump cycles in a given period of time can be used as a measure of the amount of condensate conveyed and therefore produced. By a water level sensor in the condensate pan or in the condensate tank can be closed in a simple way to the condensation rate. For this purpose, for example, over a defined period At the water level is measured, and first determines based on the known dimensions of the condensate tray, the amount of the condensed-out from the laundry to be dried water m _H 2o, from which then results in the condensation rate K.

When a water level sensor is used, its type is not limited in the present invention. Preferably, however, an analogue water level sensor is used. But it could also be provided, for example, for other reasons, a water level sensor in the condensate tray or in the condensate tank, which then could be used.

Preferably, therefore, the time course of the amount of condensed water, i. the condensation rate, by means of a water level sensor, which is arranged in a arranged below the heat exchanger condensate pan or in a condensate tank, determined.

Alternatively, it is preferred that a flow sensor is arranged in the condensate channel. The condensate channel here is the channel in which the condensate is removed, for example, from the condensate tray in the condensate tank. Also by a flow sensor arranged in such a way can be concluded in a simple manner on the condensation rate, for example, by the flow is measured over a defined period of time, from which the amount of the auskondensierten from the laundry items to be dried water m _H 2o is determined, which then the condensation rate K results. Alternatively or in addition to the above determination method, the condensation rate is thus determined by means of a flow sensor which is arranged in a condensate channel. A condensation dryer generally also has a condensate pump for conveying condensate. In general, the condensate is carried away by means of the condensate pump, which can be time-controlled or "event-controlled." Timed here means a control based on predetermined time values, for example in the program sequence "Event-controlled" means that the pump triggers at a certain amount of water. In the case of "event-controlled" pumps, the condensate pump therefore generally operates only when a specific predetermined amount of water is available, with the pump generally operating at a predetermined constant delivery rate Pump with different operating and standstill phases, which can be concluded on the basis of the duration of the operating phases in a given period and thus the number of pump cycles in a given period on the subsidized and thus incurred in the heat exchanger condensate.

In a preferred embodiment of the method according to the invention, therefore, the condensation rate is determined by means of the number of pump cycles per unit time of a condensate pump arranged in the condensate duct. When the dryer is equipped with a timed pump, it is preferred that the rate of condensation be determined via a water level sensor or a flow sensor. In a case-controlled type dryer, the rate of condensation is preferably determined by the number of pump cycles in a given time period Δt. This has the advantage that no additional sensors are needed.

In the method according to the invention, preferably the temperature T _K E of the cooling medium at the inlet of the heat exchanger and with a second temperature sensor the temperature T _K A at the outlet of the heat exchanger are measured in the cooling medium channel of the heat exchanger and the time profile of a temperature difference ΔΤ _Κ = ( T _K A - T _K E) of the cooling medium used to determine the loading of the drum with laundry, for which purpose in the control device, a relationship between ΔΤ _Κ and the load for different values of the amount of condensed water, ie condensate deposited. In a preferred embodiment, for the determination of the loading of the drum with laundry a additionally stored in the control device relationship between the time course of the measured temperature with the at least one temperature sensor, the time course of the amount of condensed water, the time course of a temperature difference ΔΤ _Κ = (TKA - T _K E) of the cooling medium, where T _K E is the temperature of the cooling medium at the entrance of the heat exchanger and T _K A is the temperature of the cooling medium at the outlet of the heat exchanger, and a speed of the drum and / or a process air blower and a heating power a heating for the process air, and the loading of the drum with laundry used.

As a result, the consideration of the rotational speed of the drum is possible. The rotation of the drum affects the distribution of laundry in the drum and thus the flow of process air through the drum. In addition, this affects the drying, since initially generally a superficial drying of laundry items takes place and thus the accessibility of the wet laundry items for the warm and dry process air should preferably be considered. To improve the accuracy of the determination of the loading is provided in a preferred embodiment, that for determining the load additionally a humidity sensor is used, which determines the moisture of the laundry items in the drum. In particular, a conductivity sensor can be used as the humidity sensor, i. a sensor in which a moisture content of the items of laundry can be measured by the moisture-dependent conductivity of the items of laundry. For example, electrodes in the end shield of the drum can serve as a moisture sensor.

Incidentally, the humidity, ie the degree of drying, of the items of laundry can be determined by observing the motor current and / or a power delivered to the electric drive motor within a predetermined period of time, since a current and / or power gradient with a decreasing moisture of the laundry items smaller becomes. If, in addition, the time-dependent moisture content of the items of laundry is taken into account for the determination of the loading, this has the advantage that exact values for the loading can be determined even under very different conditions, for example if the loading is determined relatively late in the drying process or if already relatively dry laundry is placed in the dryer.

A suitable moisture-determining device and a method for operating such a condensation dryer are described, for example, in EP 2 227 585 B1.

In general, a drying process in tumble dryers is divided into three phases. First, the heating phase takes place during which the temperature of the process air at a considered location, such as an input or output of the drum, increases until a certain temperature value is reached. This is followed by the main drying phase, in which the dryer is operated in a quasi-stationary thermodynamic state, ie the temperature of the process air is approximately constant at a considered location. This phase is therefore also referred to as "equilibrium phase." The main drying phase begins when a certain value of the process air temperature is reached (threshold value) and the further drying process takes place at approximately the same process air temperature The correlation between the time course of the temperature and / or temperature difference measured with the at least one temperature sensor and the load of laundry items is comparatively complicated during the heating phase Loading as early as during the heating phase in the control device as much data on relationships between the load and the measured temperature values and condensation rates deposited etc. On the other hand, an early Fest laying or adaptation of a drying process to a loading desirable. In a preferred embodiment of the method according to the invention, therefore, the loading is determined during the heating phase and / or at the beginning of the main drying phase. In a particularly preferred embodiment, the loading is determined at the beginning of the main drying phase. In this case, it is particularly preferred if the time period for determining the condensation rate At is as low as possible, and thus corresponds to At _min . Such a determination of the loading B allows an early adjustment of the further course of the drying process to the load.

The amount of water condensed out of the items to be dried m _H 2o and thus the condensation rate K can be determined in various ways. For example, over a defined period of time with a water level sensor, the water level in the condensate tray or in the condensate tank can be measured and used to deduce the condensation rate K. Alternatively, with time control of the condensate pump by means of a flow sensor, the amount of water delivered in a given time period can be measured.

According to the invention, the loading determination thus comprises a determination of the condensation rate K. For different condensation rates, corresponding values for the loading are then generally stored in the control device. In particular, the load correlates with the condensation rate K, since with a small load of laundry, the process air absorbs less moisture from the laundry than with a large load of laundry. For a large load, the condensation rate K is thus high, whereas at a lower load the condensation rate K is smaller. In general, the condensation rate is largely independent of the initial moisture content of the laundry. The initial moisture content of the laundry generally affects mainly the duration of the drying process, but hardly the condensation rate.

In general, the condensation rate K is decisively influenced by the temperature of the cooling medium T _K in the heat exchanger for dehumidifying the process air. The cooling medium in the heat exchanger for dehumidifying the process air serves to cool the process air and thus leads to the desired condensation. Thus, the lower the temperature of the cooling medium T _K , the greater the condensation rate K becomes. The temperature of the cooling medium T _K may vary, for example, depending on the ambient temperature of the tumble dryer. In particular, this cooperation will hang in tumble dryers with air / air heat exchangers, which use the ambient air as a cooling medium and in which thus the condensation rate K depends on the ambient temperature. A large condensation rate K could thus indicate both a high load and / or a low ambient temperature.

This means that the at least one temperature sensor is arranged such that it can determine the temperature of the cooling medium T _K. The coolant channel is in this case generally the arrangement surrounding the cooling medium directly, for example in air / air heat exchangers, the cooling air guide from the entry of cooling air in the dryer to its exit from the tumble dryer or heat pump dryers the corresponding leadership of the refrigerant.

Preferably, therefore, not only the dependence on the condensation rate K, but also the dependence on the temperature of the cooling medium T _{K is} determined and taken into account by suitable relationships, which are stored in the control device for the determination of the load for determining the loading of the clothes dryer. The temperature of the cooling medium T _{K is} preferably determined at a time within the period At, in which the condensation rate is determined. Incidentally, it is preferred according to the invention that the temporal tracking of temperatures, temperature differences, condensation rates, etc. occur in the same period. In this case, a measurement can be made in one or more time periods. The loading of the laundry dryer with items of laundry is generally determined by respective values for the loading B being stored in the control device for different condensation rates K at different temperatures of the cooling medium T _K. Thus, the loading B can be determined exactly. According to the invention, it is preferred that the temperature sensor is arranged at the cooling medium inlet of the heat exchanger. This means that the temperature sensor is arranged there in the coolant channel, where the cooling medium enters the heat exchanger. For example, this is the entry point of the cooling air into the air / air heat exchanger or the entry of the refrigerant into the evaporator. By such an arrangement can the most accurate possible statement about the temperature of the cooling medium T _{K are} taken, which then determines the condensation rate K in the device for dehumidifying the process air. In a particularly preferred embodiment, a further temperature sensor is arranged on the cooling medium outlet of the device for dehumidifying the process air. The further temperature sensor is arranged there in the coolant channel, where the cooling medium exits from the heat exchanger. For example, this is the exit point of the cooling air from the air / air heat exchanger or the outlet of the refrigerant from the evaporator. In this way, a temperature difference ΔΤ _{Κ of} the cooling medium between the temperature of the cooling medium at the inlet T _K E and the temperature of the cooling medium at its outlet TKA can be determined from the device for dehumidification. The temperature difference _ΔΤ Κ of the cooling medium enables a statement to the "cooling power" of the heat exchanger. Thus, a particularly accurate basis for determining the load is delivered. In this embodiment, the loading, in particular as a function of the condensation rate K and the two temperature values T _K E and TKA is determined or depending on the condensation rate K and the temperature difference ΔΤ _Κ , generally by depositing corresponding data in the control device, so that the load can be accurately determined.

If present in the condensation dryer, the condensate tank may be fixed or removable in the condensation dryer.

As a result of determining the loading of the laundry dryer with laundry articles, a drying process adapted to the load can be carried out. In particular, the power of the heater, the fan speed (process air fan, cooling fan, if present), the drum speed and / or a duration of the drying process can be suitably selected to achieve an optimum drying result.

The invention has the advantage that a dryer can be operated with improved efficiency. In particular, the invention allows the course of a drying process to be adapted individually to the load. As a result, insufficient drying or overdrying of the items of laundry is avoided. par- In addition, a desired final moisture content can be achieved by the invention. Thus, the user can select how "dry" he wants the laundry, and by avoiding overdrying, the laundry is also spared, and with a load that is less than the rated load, the adaptation of the drying process to this has possible reduced loading In addition, it has the advantage that a reduction in the drying time and a reduced energy consumption are achieved than in the case of known drying methods, in which case the invention makes it possible to determine the load very precisely by using a plurality of determination methods.

Further details of the invention will become apparent with reference to Figures 1 and 2 of the accompanying drawings of the following description of two non-limiting embodiments of a dryer according to the invention, in which a method according to the invention can be carried out. Show it:

FIG. 1 shows a vertical section through a condensation dryer, which has the heat exchanger for dehumidifying the process air as the evaporator of a heat pump, according to a first embodiment of the invention.

FIG. 2 shows a vertical section through a condensation dryer, which has an air / air heat exchanger as a heat exchanger for dehumidifying the process air, according to a second embodiment of the invention.

In FIGS. 1 and 2, the arrows with the arrowhead filled in indicate the flow direction of the process air.

Figure 1 thus shows a vertical section through a condensation dryer 1, which has the heat exchanger 15, the evaporator of a heat pump 12, 13, 14, 15 and a rotatable about a horizontal axis drum 3 as a drying chamber, within which driver 21 for moving laundry during a drum rotation are attached. At the drivers 21, a humidity sensor 34, designed here as a conductivity sensor, mounted to the moisture from the drum To be able to determine introduced laundry items. In the closed process air duct 2, process air is conducted by means of a process air blower 6 via an electric heater 4. The thereby heated process air then passes into the drum 3, where in Fig. 1, not shown wet laundry items moisture is removed. In this case, the process air heated by the electric heater 4 is directed from the rear, ie from the side of the drum 3 opposite a dryer door 22, through the perforated bottom into the drum 3. The moist, warm process air leaves the drum 3 via a fluff grate 31 and flows in the process air duct 2 to the evaporator 15 of the heat pump. In the evaporator 15, a refrigerant circulating in the heat pump circuit 12, 13, 14, 15 is evaporated due to the heat exchange with the moist, warm process air and fed to a condenser 12 via a compressor 13. The moist, warm process air is thereby cooled in the evaporator 15 of the heat pump 12, 13, 14, 15 and the vaporized refrigerant of the heat pump via a compressor 13 to the condenser 12, where the refrigerant with heat transfer to the flowing in the process air duct cooled and dehumidified process air liquefied. The liquid then present in liquid form is passed via a throttle valve 14 in turn to the evaporator 15, whereby the refrigerant circuit is closed.

In the first embodiment shown in Figure 1, a first temperature sensor 27 is arranged at the inlet of the refrigerant in the evaporator 15 and a second temperature sensor 28 at the outlet of the refrigerant from the evaporator 15, which the respective temperature T _K E and T _K A of the Heat pump circuit 12, 13, 14,15 circulating refrigerant measure. The resulting condensate in the evaporator 15 is collected in a condensate pan 17 and pumped by means of a condensate pump 20 in a condensate channel 18 in a condensate tank 19. In the condensate tray 17 is a water level sensor 1 1, which is designed here as a reed contact in conjunction with a permanent magnetic float. The condensate pump 20 can be controlled so that it starts only at a predetermined minimum volume of condensate, but interrupts their operation below this value. From the number of pump cycles per unit time can then be closed to the amount of condensate generated per unit time, ie the condensation rate.

Alternatively or in addition thereto, a flow meter 32 in the condensate channel 18 can be used to determine the condensation rate. The drum 3 is mounted in the embodiment shown in Figure 1 at the rear bottom by means of a pivot bearing and front by means of a bearing plate 7, wherein the drum 3 rests with a brim on a sliding strip 8 on the bearing plate 7 and is held at the front end. The control of the dryer via a control device 10, which can be controlled by the user via an operating unit 9.

A display device 33 allows the display of a detected load or other conditions of the dryer, such as e.g. Remaining time of a drying process.

In the first embodiment shown in FIG. 1, the dryer for determining the load with items of laundry in particular has the control device 10, the water level sensor 11 and a first temperature sensor 27 and a second temperature sensor 28. At the beginning of the main drying phase, ie when a predefined threshold value of the process air temperature has just been reached, the water level in the condensate pan 17 is measured over the period At-1 by means of the water level sensor 11. By means of these data, the amount of condensed water m _H 2ox is first determined in the control device 10 on the basis of the stored dimensions of the condensate tray 17. Based on the specific period At _x , the condensation rate K _x is then determined. In addition, right at the beginning of the period At-ι with the two temperature sensors 27 and 28, the temperatures T _K E and TKA of circulating in the heat pump circuit 12,13, 14, 15 refrigerant measured and also transmitted to the control device 10. From these temperatures T _K E and T _K A, the temperature difference of the refrigerant ΔΤ _{Κχ is first} determined in the control device ₁₀ . The thus determined values for the condensation rate K _x and the temperature difference of Refrigerant ΔΤ _Κχ are then compared with stored in the control _device 10 values for the condensation rate K and the temperature difference of the refrigerant ΔΤ _Κ and determined at matching values of the corresponding deposited value for the load B.

On the basis of the load value determined in this way, the further course of the drying process in the control device 10 is then adapted to the load in a manner not described here in detail. FIG. 2 shows a vertical section through a condensation dryer, which has an air / air heat exchanger as a heat exchanger for dehumidifying the process air, according to a further embodiment of the invention.

Instead of an evaporator, an air / air heat exchanger 5 is used in the second embodiment shown in Figure 2. The process air is performed in this dryer substantially as shown for Figure 1. However, the moist, warm process air after exiting the drum 3 via the process air duct 2 for dehumidification is not passed to the evaporator of a heat pump, but to the air / air heat exchanger 5, where it is cooled. As a result of cooling, the moisture absorbed by the process air from the items of laundry condenses there and is collected in the condensate tray 17. In the condensate tray 17 is a water level sensor 1 1.

In contrast to the first embodiment of Figure 1, the cooling of the warm, laden with moisture process air from the drum 3 in the air / air heat exchanger 5 takes place by heat exchange with cooling air as the cooling medium. The cooling air enters from the installation room of the dryer 1 through the cooling air inlet 23 into the cooling air duct 24 and is conveyed through the cooling air blower 25 through the air / air heat exchanger 5 to the cooling air outlet 26. In the second embodiment shown in Figure 2, a first temperature sensor 29 at the inlet of the cooling air in the air / air heat exchanger 5 and a second temperature sensor 30 at the outlet of the cooling air from the air / air heat exchanger 5 is arranged. The two temperature sensors measure the temperatures T _K E and T _K A of the cooling air. The condensate pump 20 can be controlled so that it starts only at a predetermined minimum volume of condensate, but interrupts their operation below this value. From the number of pump cycles per unit time can then be closed to the amount of condensate generated per unit time.

Alternatively or in addition thereto, a flow sensor 32 in the condensate channel 18 can be used to determine this condensation rate.

In the embodiment of Figure 2, the process air blower 6, the Kühlluftge- blower 25 and the drum 3 are driven by the same motor 16, wherein the fan 6 and the cooling air blower 25 are on opposite sides of the motor 16.

In the case of the second embodiment shown in FIG. 2, the dryer for determining the load with laundry items likewise has in particular the control device 10, the water level sensor 11 and a first temperature sensor 29 and a second temperature sensor 30 in the cooling medium channel 24 configured as a cooling air channel. Similar to the first embodiment shown in Figure 1, the water level in the condensate pan 17 is measured at the beginning of the main drying phase over a period At _Y by means of the water level sensor 1 and determined on the basis of which in the control device 10, the condensation rate K. In addition, the temperatures T _K E and T _K A of the cooling air are measured right at the beginning of the period At-i with the temperature sensors 29 and 30 and likewise transmitted to the control device 10. From the temperatures T _K E and T _K A, the temperature difference of the cooling air ΔΤ _{Κ is first} determined in the control device 10. The values thus determined for the condensation rate K and the temperature difference ΔΤ _{Κ of} the cooling air are then compared with the values stored for the condensation rate K and the temperature difference ΔΤ _{Κ of} the cooling air in the control device 10 and the corresponding stored value for the load is determined for corresponding values.

At the entrainment 21 is a humidity sensor 34, designed here as a conductivity sensor, mounted to determine the humidity of introduced into the drum laundry. Otherwise, not separately listed reference numerals have the same meaning as for Figure 1. Also in the second embodiment, the further course of the drying process is then determined in the control device 10 on the basis of the loading value thus determined, wherein the load of laundry items can be taken into account.

LIST OF REFERENCE NUMBERS

1 dryer, condensation dryer

2 process air duct

3 drum

4 heating, especially electric heating

5 heat exchangers; Air to air heat exchanger 6 Process air blower

7 end shield

8 sliding strips

9 operating unit

10 control device

1 1 water level sensor

12 liquefier

13 compressor

14 throttle valve

15 evaporator

16 engine

17 condensate tray

18 condensate channel

19 condensate tanks

20 pump, condensate pump

21 (laundry) driver

22 door, drying door

23 cooling air inlet

24 cooling medium channel; Cooling air duct; Refrigerant passage

25 cooling air blower

26 Cooling air outlet

27 First temperature sensor in the refrigerant channel

28 Second temperature sensor in the refrigerant channel

29 First temperature sensor in the cooling air duct Second temperature sensor in the cooling air duct Fluff grate

Flow Sensor

Display device, optical / acoustic

Claims

PATENT CLAIMS

Condensation dryer (1) with a process air duct (2), a drum (3) for holding laundry items, a heat exchanger (5, 15) for condensing water from warm, moist process air, a control device (10), at least one temperature sensor (27, 28, 29,30) and a device (11,20,32) for determining the amount of water condensed in the heat exchanger, characterized in that the at least one temperature sensor (27,28,29,30) in a cooling medium channel (24) and / or is arranged in the process air duct (2) and the control device (10) is set up to determine a load based on a time profile of the temperature measured with the at least one temperature sensor (27,28,29,30) and a time profile of the amount of condensed water the drum (3) with laundry items.

Condensation dryer (1) according to claim 1, characterized in that a first temperature sensor (27,29) is arranged in the cooling medium channel (24) at the inlet of the heat exchanger (5, 15) for the cooling medium.

Condensation dryer (1) according to claim 2, characterized in that a second temperature sensor (28,30) is arranged in the cooling medium channel (24) at the outlet of the heat exchanger (5,15) for the cooling medium.

Condensation dryer (1) according to one of claims 1 to 3, characterized in that the heat exchanger (5, 15) is an evaporator (15) of a heat pump (12, 13, 14, 15).

5. Condensation dryer (1) according to one of claims 1 to 3, characterized in that the heat exchanger (5, 15) is an air-air heat exchanger (5). Condensation dryer (1) according to one of claims 1 to 5, characterized in that a water level sensor (1 1) is arranged in a condensate pan (17) below the heat exchanger (5, 15) or in a condensate container (19).

Condensation dryer (1) according to one of claims 1 to 6, characterized in that a flow sensor (32) is arranged in a condensate channel (18).

Method for operating a condensation dryer (1) with a process air duct (2), a drum (3) with items of laundry placed therein, a heat exchanger (5, 15) for condensing water from warm, moist process air, a control device (10), at least one temperature sensor ( 27,28,29,30) and a device (11,20,32) for determining the amount of water condensed in the heat exchanger (5,15), the at least one temperature sensor (27,28,29,30) in one Cooling medium channel (24) and/or in the process air channel (2) is arranged and the control device (10) is set up to use a time course of the temperature measured with the temperature sensor (27,28,29,30) and a time course of the amount condensed water to determine the load of the drum (3) with the laundry items,

characterized in that for at least a predetermined period of time At-i, the time course of the temperature measured with the at least one temperature sensor (27,28,29,30) and the time course of the amount of condensed water are determined and by comparison with one in the Control device (10) stored connection between these time profiles and the loading of the drum (3) a loading of the drum (3) with laundry items is determined.

Method according to claim 8, characterized in that in the cooling medium channel (24) of the heat exchanger (5, 15) with a first temperature sensor (27,29) the temperature T _K E of the cooling medium at the inlet of the heat exchanger and with a second temperature sensor (28,30 ) the temperature TKA is measured at the outlet of the heat exchanger (5, 15) and the time course of a temperature difference ΔΤ _Κ = (TKA - T _K E) of the cooling medium to determine the loading of the drum (3) with items of laundry is used, for which purpose a connection between AT _K and the load for different values of the amount of condensed water is stored in the control device (10).

10. The method according to claim 8 or 9, characterized in that for the determination of the loading of the drum (3) with items of laundry, a relationship additionally stored in the control device (10) between the time course of the with the at least one temperature sensor (27, 28, 29.30) measured temperature, the time course of the amount of condensed water, the time course of a temperature difference ΔΤ _Κ = (TKA - T _K E) of the cooling medium, where T _K E is the temperature of the cooling medium at the inlet of the heat exchanger (5.15 ) and T _K A is the temperature of the cooling medium at the outlet of the heat exchanger (5,15), and a speed of the drum (3) and / or a process air blower (6) as well as a heating output of the heater (4), and the loading of the drum (3) is used with laundry items.

1 1. The method according to one of claims 8 to 10, characterized in that the time course of the amount of condensed water, i.e. the condensation rate, by means of a water level sensor (1 1) in a condensate pan (17) arranged below the heat exchanger or in is arranged in a condensate container (19).

12. The method according to any one of claims 8 to 1 1, characterized in that a condensation rate is determined by means of a flow sensor (32) which is arranged in a condensate channel (18).

13. The method according to one of claims 8 to 12, characterized in that to determine the load, a moisture sensor (34) is also used, which determines the moisture of the laundry items in the drum (3).

14. The method according to any one of claims 8 to 13, characterized in that a condensation rate is determined by means of the number of pump cycles per unit of time of a condensate pump (20) arranged in the condensate channel (18). Method according to one of claims 8 to 14, characterized in that the load is determined during a heating phase and/or at the beginning of a main drying phase.