CONDENSER TUMBLE DRYER COMPRISING A TEMPERATURE SENSOR, AND METHOD FOR THE OPERATION THEREOF

Abstract

The invention relates to a condenser tumble dryer with a drum for articles to be dried, a drive motor for the drum, a process air duct, a process air blower, a heating and cooling system for the process air, a temperature sensor and a control device. The temperature sensor is an infrared telescope and is arranged to simultaneously measure heat radiation from at least two components of the condenser tumble dryer which are to be monitored. The invention also relates to a method for operating a condenser tumble dryer of said type.

Claims

1. A condenser tumble dryer (1) with a drum (2) for articles (4) to be dried, a drive motor (28) for the drum (2), a process air duct (24), a process air blower (27), a heating and cooling system (14, 16, 18, 19, 25, 30) for the process air (11), a temperature sensor (21) and a control facility (20), characterized in that the temperature sensor (21) is an infrared telescope (21) arranged for the simultaneous measurement of thermal radiation from at least two components (5, 14, 16, 18, 19, 24, 25, 27, 28, 30) of the condenser tumble dryer (1) which are to be monitored.

2. The condenser tumble dryer (1) as claimed in claim 1, wherein the components (5, 14, 16, 18, 19, 24, 25, 27, 28, 30) which are to be monitored are selected from the group comprising an outer surface (5) of the drum (2), the process air duct (24), the components of the heating and cooling system (14, 16, 18, 19, 25, 30), the process air blower (27) and the drive motor (28).

3. The condenser tumble dryer (1) as claimed in one of the preceding claims, characterized in that the infrared telescope (21) contains a thermopile array (21).

4. The condenser tumble dryer (1) as claimed in claim 3, characterized on that an imaging lens is provided before the thermopile array (21) to generate an image of a respective measurement point (36) of each of the components (5, 14, 16, 18, 19, 24, 25, 27, 28, 30) to be monitored on the thermopile array (21).

5. The condenser tumble dryer (1) as claimed in claim 4, characterized in that the measurement point (36) comprises a coating (36), which has a predetermined thermal radiation emission coefficient.

6. The condenser tumble dryer (1) as claimed in one of claims 3 to 5, characterized in that a respective thermopile of the thermopile array (21) is assigned to each component (5, 14, 16, 18, 19, 24, 25, 27, 28, 30) to be monitored so that the thermal radiation from the respective component (5, 14, 16, 18, 19, 24, 25, 27, 28, 30) to be monitored is measured by the respective assigned thermopile.

7. The condenser tumble dryer (1) as claimed in one of the preceding claims, characterized in that the control facility (20) is set up to evaluate the thermal radiation measured in each instance by the infrared telescope (21) for the components (5, 14, 16, 18, 19, 24, 25, 27, 28, 30) to be monitored, for the monitoring and/or control of the condenser tumble dryer (1).

8. The condenser tumble dryer (1) as claimed in one of the preceding claims, characterized in that the heating and cooling system (14, 16, 18, 19, 25, 30) for the process air (11) contains a heat pump (14, 16, 18, 19) with an evaporator (14), a compressor (18), a condenser (16) and a throttle unit (19).

9. The condenser tumble dryer (1) as claimed in claim 8, characterized in that the components (5, 14, 16, 18, 19, 24, 25, 27, 28, 30) to be monitored comprise the evaporator (14), the compressor (18), the condenser (16) and/or the throttle unit (19).

10. The condenser tumble dryer (1) as claimed in claim 9, characterized in that the components (5, 14, 16, 18, 19, 24, 25, 27, 28, 30) to be monitored comprise the condenser (16) and the compressor (18).

11. The condenser tumble dryer (1) as claimed in one of claims 8 to 10, characterized in that the compressor (18) is a variable-output compressor (18).

12. The condenser tumble dryer (1) as claimed in one of the preceding claims, characterized in that the components (5, 14, 16, 18, 19, 24, 25, 27, 28, 30) to be monitored comprise the outer drum surface (5).

13. The condenser tumble dryer (1) as claimed in one of the preceding claims, characterized in that the control facility (20) is set up to take into account different emission coefficients of the components (5, 14, 16, 18, 19, 24, 25, 27, 28, 30) to be monitored.

14. The condenser tumble dryer (1) as claimed in one of the preceding claims, characterized in that respective maximum permissible values for the thermal radiation from the components (5, 14, 16, 18, 19, 24, 25, 27, 28, 30) to be monitored are stored in the control facility (20) and the control facility (20) is set up to deactivate the condenser tumble dryer (1) if a maximum permissible value for the thermal radiation from the components (5, 14, 16, 18, 19, 24, 25, 27, 28, 30) to be monitored is exceeded and/or to display that the maximum permissible value is exceeded on a display apparatus (35) of the condenser tumble dryer (1).

15. A method for operating a condenser tumble dryer (1) with a drum (2) for articles (4) to be dried, a drive motor (28) for the drum (2), a process air duct (24), a process air blower (27), a heating and cooling system (14, 16, 18, 19, 25, 30) for the process air (11), a temperature sensor (21) and a control facility (20), characterized in that the temperature sensor (21) is an infrared telescope (21) arranged for the simultaneous measurement of thermal radiation from at least two components (5, 14, 16, 18, 19, 24, 25, 27, 28, 30) of the condenser tumble dryer (1) which are to be monitored and the thermal radiation from the at least two components (5, 14, 16, 18, 19, 24, 25, 27, 28, 30) to be monitored is measured by means of the infrared telescope (21) and evaluated by the control facility (20) in respect of the respective temperature of the components (5, 14, 16, 18, 19, 24, 25, 27, 28, 30) which are to be monitored and used for monitoring and/or control during operation of the condenser tumble dryer (1).

16. The method as claimed in claim 15, characterized in that the components (5, 14, 16, 18, 19, 24, 25, 27, 28, 30) which are to be monitored comprise the components of the heating and cooling system (14, 16, 18, 19, 25, 30), wherein the components, the thermal radiation from which is measured, comprise the evaporator (14), the compressor (18), the condenser (16) and/or the throttle unit (19) of a heat pump and the condenser tumble dryer (1) is controlled in such a manner that the temperature of a coolant of the heat pump is within a predetermined range.

17. The method as claimed in claim 16, characterized in that the condenser tumble dryer (1) is controlled in such a manner that the output of the compressor (18), which is a variable-output compressor (18), is varied such that the temperature of the coolant is within a predetermined range.

Description

[0058] Further details of the invention will emerge from the description which follows of non-restricting exemplary embodiments of the inventive condenser tumble dryer and a method employing said condenser tumble dryer. Reference is made here to FIGS. 1 to 3, in which:

[0059] FIG. 1 shows a perspective view of the parts of a condenser tumble dryer that are of essence to the invention according to a first embodiment, in this instance a heat pump tumble dryer,

[0060] FIG. 2 shows a vertical section through a condenser tumble dryer according to a second embodiment, in this instance also a heat pump tumble dryer,

[0061] FIG. 3 shows a vertical section through a condenser tumble dryer according to a third embodiment, configured as a condenser tumble dryer with an air to air heat exchanger.

[0062] FIG. 1 shows a perspective view of the parts of a condenser tumble dryer that are of essence to the invention according to a first embodiment, which is a heat pump tumble dryer 1.

[0063] FIG. 1 shows the drum 2 with an outer drum surface 5 and the components of a heat pump, i.e. an evaporator 14, a condenser 16, a compressor 18 and the pipes 23 connecting them. A thermopile array 21 is arranged in such a manner that the thermal radiation from the components of the heat pump and also the drum 2 can be received. The field of view or detection range for paths 22 of the thermal radiation from the components of the tumble dryer to the infrared telescope 21 is shown here by an ellipse marked with a broken line.

[0064] The infrared telescope 21 here comprises a thermopile array 21 and an imaging lens positioned before it, the latter not being shown for reasons of clarity. Said lens can have a focal length of several millimeters to a few centimeters and the thermopile array 21 is in its focal plane. This allows an image of the surroundings of the infrared telescope 21 to be generated on the thermopile array 21 so that different thermopiles therein measure temperatures at different sites in the laundry dryer 1. It goes without saying that a different infrared sensor system with an extensive surface can replace the thermopile array 21.

[0065] FIG. 2 shows a vertical section through a condenser tumble dryer according to a second embodiment, in this instance a heat pump tumble dryer. The condenser tumble dryer 1 has a cylindrical laundry drum 2, which can be rotated about an essentially horizontally aligned (rotation) axis 3 and in which laundry articles 4 are present, which are in particular to be dried in the condenser tumble dryer 1.

[0066] The drum 2 is made of stainless steel and has a cylindrical casing with a cylindrical outer drum surface 5. The cylindrical casing supports agitators (not shown here), which are to help raise the laundry articles 4. Adjoining the casing at the front of the laundry drum 2 is a circular front facing wall, through which the laundry articles 4 can be introduced into the drum 2. The corresponding opening in the front facing wall 6 is closed by a door 7. Adjoining the casing at the rear of the laundry drum 2 is a circular rear facing wall 8, which has perforations 9. Bearings and seals, against or on which the drum 2 rests or which seal it from its surroundings, are not shown here. The perforations 9 are covered by a hood 10 at the rear of the laundry drum 2. A drive motor for the drum, which is generally present, is not shown for the sake of clarity.

[0067] A flow of process air 11 conducted in the essentially closed process air duct and driven by a process air blower (not shown here) passes into the drum 2 and reaches the laundry items 4 contained therein and moved by rotation of the drum 2. The process air 11 passes through the hood 10 and the perforations 9 into the drum 2 to flow round the laundry articles 4 there and extract moisture therefrom. In the region of the door 7 the process air 11 passes out of the drum 2 into the process air duct in the bearing plate 12 where it flows through a lint filter 13 which traps fibers and other fine particles (generally referred to as lint) that the process air 11 has drawn out of the laundry articles 4. Below the drum 2 the process air 11 exits from the bearing plate 12 again and passes to the evaporator 14 of a heat pump. Heat is extracted from the moist warm process air there so that the moisture extracted from the damp laundry items 4 and contained therein condenses and can be discharged as liquid condensate. The condensate is collected in a condensate tray 15 and generally conducted to a condensate container (not shown here) which can be emptied to dispose of the condensate. Behind the evaporator 14 the process air 11, from which moisture has now been extracted, passes into the condenser 16 of the heat pump where it is heated again and thus made ready to absorb further moisture from the laundry articles 4. Behind the condenser 16 the process air passes back into the hood 10 and the drum 2.

[0068] In the heat pump a coolant, which circulates in a closed coolant circuit 17 and some of which is supplied to the evaporator 14 in liquid form, evaporates, extracting heat from the moist warm process air 11 flowing through. The evaporated coolant is then compressed by a compressor 18, being heated in the process, and then passes into the condenser 16. In the condenser 16 the coolant returns the heat absorbed in the evaporator 14 to the process air flowing through. Behind the condenser 16 the condensed coolant passes back through a throttle unit 19, which reduces its internal pressure and temperature, to the evaporator 14 to be evaporated again, thereby absorbing heat. The coolant is generally a short-chain fluorinated hydrocarbon or a mixture of such substances, in particular for example the substances known in this context R134a and R407C. Propane, generally referred to as R290, is also a possible coolant. The compressor 18 here is a variable-output compressor, the output of which can be adjusted based on the temperature of the components of the heat pump measured by the thermopile array 21 and therefore the temperature of the coolant in order to keep the temperature of the coolant within an optimum range.

[0069] A control facility 20 controls all the functions of the condenser tumble dryer 1. To this end it receives the thermal radiation values measured by the thermopiles of the thermopile array 21 for each component and activates corresponding actuators, in particular the drive motor of the drum 2, the process air blower for the process air 11 and the compressor 18. The thermopile array 21 is arranged in such a manner that it can measure the thermal radiation (shown with a broken line) from the outer drum casing 5, as well as from the compressor 18, throttle unit 19, evaporator 14 and condenser 16. A shared lens positioned in front is not shown here.

[0070] As the emission coefficient for thermal radiation is below 10% for stainless steel, thermal radiation from defined measurement points (not shown in detail here) is preferably measured, preferably from one measurement point per measured component. To this end the point can be provided with a suitable coating that increases thermal radiation. The shared lens then has the task of conducting the thermal radiation originating from the measurement point specifically to a thermopile of the thermopile array 21. The thermal radiation value measured by the thermopile can then be supplied to the control facility 20 for evaluation.

[0071] FIG. 3 shows a vertical section through a condenser tumble dryer according to a third embodiment, configured as a condenser tumble dryer with an air to air heat exchanger.

[0072] The condenser tumble dryer 1 shown in FIG. 3 has a drum 2, which can be rotated about a horizontal axis 3, for holding laundry articles to be dried (not shown here), agitators 26 for moving laundry articles during a drum rotation being positioned therein. The process air 11 is conducted through the drum 2 in the process air duct 24 by means of a process air blower 27 by way of an air to air heat exchanger 30 and an electric heater 25. In this process, process air 11 heated by the electric heater 25 is conducted through the drum entrance 34 from the rear, in other words from a side of the drum 2 opposite a door 7, through its perforated base into the drum 2.

[0073] After leaving the drum 2, the moisture-laden process air 11 flows through the fill opening of the drum 2 by way of a lint filter 13 within the door 7 closing the fill opening. The flow of process air 11 in the door 7 is then deflected downward through the drum exit 33 into the process air duct 24 and conducted to the air to air heat exchanger 30, through which cooling air can be conveyed in a cooling air duct 31 by means of a cooling air blower 32. In the air to air heat exchanger 30 cooling causes a variable proportion of the moisture absorbed from the laundry articles by the process air to condense and be collected in a condensate tray 15.

[0074] The condenser tumble dryer 1 is controlled by way of a program controller 20, which can be operated by the user by way of an operating unit 29. In the condenser tumble dryer 1 illustrated here a thermopile array 21 is arranged in such a manner that it can detect and therefore measure the thermal radiation from measurement points 36 on the outer drum surface 5, the air to air heat exchanger 30, the process air blower 27 and the electric heating apparatus 25. These measurement values are supplied to the control facility 20 for evaluation and the possible prompting of further steps. After evaluating the measured thermal radiation the control unit 20 can control for example the electric heating apparatus 25, the drive motor 28, the process air blower 27 and/or the cooling air blower 32 in such a manner that a drying program operates optimally and a predetermined laundry moisture content for example is reached.

[0075] In the third embodiment shown in FIG. 3 the process air blower 27 and the drum 2 are driven by the drive motor 28. In this embodiment the drive motor 28 is a brushless direct current motor (BLDC). The drum 2 is stepped down significantly, for example with a 1:55 ratio, while the process air blower 27 is not stepped down but driven by the drive motor 28 with a rotational speed ratio of 1:1.

[0076] In the condenser tumble dryer 1 each component 25, 30 is assigned a thermopile of the thermopile array 21 so that the thermal radiation from the respective component is measured by the assigned thermopile. In the illustrated embodiment the thermopile array 21 is arranged so that it can measure thermal radiation from the outer drum surface 5. The control facility 20 is set up to take into account different degrees of emission of the components 25, 30.

[0077] Finally in this embodiment of the condenser tumble dryer 1 maximum permissible values for the thermal radiation from the components 25, 30 are stored in the control facility 20 and the control facility 20 is set up to deactivate the condenser tumble dryer 1 if a permissible value for the thermal radiation from the components 25, 30 is exceeded and to display that the maximum permissible value is exceeded on a display apparatus 35 of the condenser tumble dryer 1.

LIST OF REFERENCE CHARACTERS

[0078] 1 Condenser tumble dryer [0079] 2 Drum (for holding laundry articles to be dried) [0080] 3 Rotation axis [0081] 4 Laundry articles [0082] 5 Drum casing, outer drum surface [0083] 6 Front facing wall [0084] 7 Door [0085] 8 Rear facing wall [0086] 9 Perforation [0087] 10 Hood [0088] 11 Process air [0089] 12 Bearing plate [0090] 13 Lint filter [0091] 14 Evaporator [0092] 15 Condensate tray [0093] 16 Condenser [0094] 17 Coolant circuit [0095] 18 Compressor [0096] 19 Throttle unit [0097] 20 Control facility [0098] 21 Thermopile array (comprising a number of thermopiles) [0099] 22 Path of thermal radiation from components to thermopile array [0100] 23 Pipes between evaporator, condenser, compressor and throttle unit [0101] 24 Process air duct [0102] 25 Electric heating apparatus [0103] 26 Agitator [0104] 27 Process air blower [0105] 28 Drive motor; e.g. variable-speed drive motor, in particular BLDC motor [0106] 29 Operating unit [0107] 30 Air to air heat exchanger [0108] 31 Cooling air duct [0109] 32 Cooling air blower [0110] 33 Drum exit [0111] 34 Drum entrance [0112] 35 Optical display apparatus [0113] 36 Measurement points