CONDENSER TUMBLE DRYER HAVING A HEAT PUMP AND A RECIRCULATED AIR PORTION AND METHOD FOR THE OPERATION THEREOF

Abstract

A dryer has a drum for laundry items to be dried, a supply air channel, an exhaust air channel, a recirculated air channel branching off therefrom and discharging into the supply air channel upstream of a drum inlet, a blower, a heat pump having a condenser disposed in the supply air channel, an evaporator disposed in the exhaust air channel, a throttle, a compressor, a controller and a heater. The dryer is configured such that moist warm air flows out of the drum in an exhaust air channel part, substantially in the same direction as the supply air in an inlet part of the supply air channel containing the condenser. The process air leaving the drum has a relative air humidity F.sup.rel, to which F.sup.rel.sub.min?F.sup.rel?F.sup.rel.sub.max applies, wherein F.sup.rel.sub.min is a predetermined minimum value and F.sup.rel.sub.max is a maximum value of the relative air humidity.

Claims

1-15. (canceled)

16. A condenser tumble dryer, comprising: a drum for receiving laundry items to be dried and having a drum inlet; a supply air channel having an inlet region; an exhaust air channel; a recirculated air channel branching off from said exhaust air channel and discharging into said supply air channel upstream of said drum inlet; a blower; a heat pump having a condenser disposed in said supply air channel, an evaporator disposed in said exhaust air channel, a throttle and a compressor; a controller; a heater; an exhaust air channel part; and the condenser tumble dryer being configured such that, in a drying program carried out therein, moist warm process air flows out of said drum in said exhaust air channel part defined downstream by said evaporator, substantially in a same direction as supply air in said inlet region of said supply air channel containing said condenser, and the moist warm process air leaving said drum having a relative air humidity F.sup.rel, to which F.sup.rel.sub.min?F.sup.rel?F.sup.rel.sub.max applies, wherein F.sup.rel.sub.min is a predetermined minimum value and F.sup.rel.sub.max is a maximum value of a relative air humidity which can be achieved in the drying program.

17. The condenser tumble dryer according to claim 16, wherein said recirculated air channel discharges into said supply air channel in a direction of flow of the supply air downstream of said condenser.

18. The condenser tumble dryer according to claim 16, wherein said recirculated air channel discharges into said supply air channel in a direction of flow of the supply air upstream of or at said condenser.

19. The condenser tumble dryer according to claim 18, further comprising in each case a flow measuring unit disposed in said supply air channel upstream and downstream of said condenser.

20. The condenser tumble dryer according to claim 18, wherein said exhaust air channel part and said condenser have a common wall which has a plurality of holes formed therein which form said recirculated air channel.

21. The condenser tumble dryer according to claim 20, wherein said plurality of holes is located in an inlet region of said condenser.

22. The condenser tumble dryer according to claim 20, wherein said plurality of holes is configured in the drying program and carried out in the condenser tumble dryer in cooperation with said blower to form an air volume flow through said condenser, such that the air volume flow consists of 15 to 50% by volume of recirculated air.

23. The condenser tumble dryer according to claim 20, further comprising an apparatus which permits a total effective opening surface of said plurality of holes to be controlled.

24. The condenser tumble dryer according to claim 16, wherein said heat pump contains an additional cooler.

25. The condenser tumble dryer according to claim 16, wherein a relationship between a rotational speed u of said blower and a ratio r between an air flow speed V.sub.C in said condenser and an air flow speed V.sub.E in said evaporator is stored in said controller.

26. The condenser tumble dryer according to claim 16, further comprising a humidity sensor disposed at an outlet of said drum for determining the relative air humidity F.sup.rel of the process air leaving said drum.

27. The condenser tumble dryer according to claim 22, wherein the air volume flow consists of 20 to 40% by volume of the recirculated air.

28. A method for operating a condenser tumble dryer having a drum for receiving laundry items to be dried, a supply air channel, an exhaust air channel, a recirculated air channel branching off from the exhaust air channel and discharging into the supply air channel upstream of a drum inlet, a blower, a heat pump having a condenser disposed in the supply air channel, an evaporator disposed in the exhaust air channel, a throttle and a compressor, a controller and a heater, wherein the condenser tumble dryer is configured such that, during a drying program carried out the condenser tumble dryer, the drying program performing the steps of: flowing moist warm process air out of the drum in an exhaust air channel part defined downstream by the evaporator, substantially in a same direction as supply air in an inlet region of the supply air channel containing the condenser; flowing the process air leaving the drum to have a relative air humidity F.sup.rel, to which F.sup.rel.sub.min?F.sup.rel?F.sup.rel.sub.max applies, wherein F.sup.rel.sub.min is a predetermined minimum value and F.sup.rel.sub.max is a maximum value of the relative air humidity which can be achieved in the drying program; and controlling the blower by the controller such that the process air leaving the drum has a relative air humidity F.sup.rel, to which F.sup.rel.sub.min?F.sup.rel?F.sup.rel.sub.max applies.

29. The method according to claim 28, which further comprises controlling the blower by the controller such that an air volume flow through the condenser consists of 15 to 50% by volume of recirculated air.

30. The method according to claim 28, which further comprises setting a ratio r between an air flow speed V.sub.C in the condenser and an air flow speed V.sub.E in the evaporator to be greater than 1.

31. The method according to claim 28, which further comprises performing the method after the process air leaving the drum has reached a predetermined minimum temperature.

32. The method according to claim 29, which further comprises controlling the blower by the controller such that the air volume flow through the condenser consists of 20 to 40% by volume of the recirculated air.

33. The method according to claim 30, which further comprises setting the ratio r between the air flow speed V.sub.C in the condenser and the air flow speed V.sub.E in the evaporator to be greater than 1.2.

Description

[0054] Further details of the invention are found in the following description of non-limiting exemplary embodiments of the condenser tumble dryer according to the invention and a method using this condenser tumble dryer. Reference is made to FIGS. 1 to 7.

[0055] FIG. 1 shows a perspective view of a condenser tumble dryer from the prior art having a heat pump, wherein no supply air channel is used for partially returning process air from the drum.

[0056] FIG. 2 shows a vertical section through the condenser tumble dryer of FIG. 1 in which the air routing through the supply air channel, drum and exhaust air channel is shown.

[0057] FIG. 3 shows a vertical section through a condenser tumble dryer according to the invention according to a first embodiment in which a part of the process air from the drum is supplied via a recirculated air channel to a condenser in the supply air channel.

[0058] FIG. 4 shows as FIG. 3 a vertical section through the condenser tumble dryer according to the invention, according to a first embodiment in which a part of the process air from the drum is supplied via a recirculated air channel to a condenser in the supply air channel. In contrast to FIG. 3, for the sake of clarity, arrows which indicate the flow of air in the 2 condenser tumble dryer are not present here.

[0059] FIG. 5 shows a diagram which shows the flow of process air through the condenser, the drum, the evaporator and a sub-cooler according to a second embodiment of the condenser tumble dryer according to the invention (thick arrows), wherein the thin arrows show the flow of a refrigerant through the components of the heat pump used.

[0060] FIG. 6 shows a diagram which shows the flow of process air through the condenser, the drum, the evaporator and a sub-cooler according to a third embodiment of the condenser tumble dryer according to the invention (thick arrows), wherein the thin arrows show the flow of a refrigerant through the components of the heat pump used.

[0061] FIG. 7 shows a perspective plan view of a lower part of a condenser tumble dryer used according to the invention, in which in particular a common wall separating the condenser from the exhaust air channel can be seen, the wall having a plurality of holes which can function as a recirculated air channel in an inlet region of the condenser.

[0062] FIG. 1 shows a perspective view of a condenser tumble dryer 1 from the prior art having a heat pump, the condenser 8 and the evaporator 9 being able to be identified therefrom. In this condenser tumble dryer, no supply air channel is used for the partial return of process air from the drum 2. The air routing through the condenser tumble dryer is illustrated by the arrows. The light arrow indicates supply air from an installation space of the condenser tumble dryer which is conveyed in the supply air channel 3 by the use of a blower, not shown here. This supply air is heated in the condenser 8 and the now warm process air is then forwarded to and into the drum 2. The now moist warm process air leaves the drum 2 at the drum outlet 18. The process air has relatively the highest temperature, which is shown by the black arrows. The moist warm process air is cooled by condensation (not shown here) of the moisture in the evaporator 9 and conveyed in the exhaust air channel 4 into an installation space of the condenser tumble dryer 1. 17 indicates a sub-cooler in the heat pump circuit.

[0063] FIG. 2 shows a vertical section through the condenser tumble dryer 1 of FIG. 1, in which the air routing through the supply air channel 3, drum 2 and exhaust air channel 4 is shown. The same reference signs have the same meaning as in FIG. 1. 7 indicates a blower.

[0064] FIG. 3 shows a vertical section through a condenser tumble dryer 1 according to the invention, according to a first embodiment in which a part of the process air from the drum 2 is supplied via a recirculated air channel 5 to a condenser 8 in the supply air channel 3. The recirculated air channel 5 here is located in an inlet part 13 of the supply air channel 3. 12 indicates an exhaust air channel in which the process air substantially flows in the same direction as in the supply air channel, i.e. in particular in the condenser 8. 7 indicates a blower and 17 a sub-cooler. The thick arrow which is split into two illustrates how a part of the moist warm process air from the drum 2 downstream of the drum outlet 18 in the region of the condenser 8 is conducted therein as recirculated air.

[0065] FIG. 4 shows as FIG. 3 a vertical section through the condenser tumble dryer 1 according to the invention, according to a first embodiment in which a part of the process air from the drum 2 is supplied via a recirculated air channel 5 to a condenser 8 in the supply air channel 3. In contrast to FIG. 3, for reasons of clarity, arrows which show the flow of air in the condenser tumble dryer 1 are not present here. Further reference signs have the same meaning as in FIG. 3.

[0066] FIG. 5 shows a diagram which shows the flow of process air through the condenser 8, the drum 2, the evaporator 8 and a sub-cooler 17 according to a second embodiment of the condenser tumble dryer 1 according to the invention (thick arrows), wherein the thin arrows show the flow of a refrigerant through the components of the heat pump used. The refrigerant is routed in the refrigerant circuit which additionally has a throttle 10 and a compressor 11. The curved thick arrow shows that a part of the process air from the drum 2 downstream of the condenser 8 is routed back into the supply air channel, not shown here, containing the condenser 8.

[0067] FIG. 6 shows a diagram which shows by thick arrows the flow of process air through the condenser 8, the drum 2, the evaporator 9 and a sub-cooler 17 according to a third embodiment of the condenser tumble dryer 1 according to the invention, wherein the thin arrows show the flow of a refrigerant through the components of the heat pump used. The refrigerant is routed in the refrigerant circuit which additionally has a throttle 10 and a compressor 11. The curved thick arrow shows that according to the invention a part of the process air from the drum 2, in comparison with FIG. 5, is preferably routed back upstream of, or at, the condenser 8 into the supply air channel, not shown here, containing the condenser 8.

[0068] FIG. 7 shows a perspective plan view of a lower part of a condenser tumble dryer used according to the invention, in which, in particular, a common wall 14 separating the condenser 8 from the exhaust air channel, not shown here, can be seen, the wall having a plurality of holes 15 in an inlet region 16 of the condenser 8. 13 indicates an inlet part of the supply air channel, also not shown here.

LIST OF REFERENCE SIGNS

[0069] 1 Condenser tumble dryer [0070] 2 Drum for receiving laundry items to be dried [0071] 3 Supply air channel [0072] 4 Exhaust air channel [0073] 5 Recirculated air channel [0074] 6 Drum inlet [0075] 7 Blower [0076] 8 Condenser [0077] 9 Evaporator [0078] 10 Throttle [0079] 11 Compressor [0080] 12 Exhaust air channel part [0081] 13 Inlet region (of supply air channel) [0082] 14 Common wall of condenser and recirculated air channel part [0083] 15 Plurality of holes (in common wall) [0084] 16 Inlet region of condenser [0085] 17 Additional cooler, sub-cooler (in heat pump) [0086] 18 Outlet (for process air from drum), drum outlet