Patent Abstract:
A laundry drier includes a filter is disposed removably in the air duct carrying the process air and is held in an at least two-part foldable frame. To extend its functionality with a view to the binding of odors from the laundry items, the filter contains a charcoal-fiber insert that is equipped to combine and/or convert odorous substances.

Full Description:
BACKGROUND OF THE INVENTION 
   Field of the Invention 
   The invention relates to a laundry drier with a removable filter that is disposed in the airflow and that is held in an at least two-part foldable frame. 
   German Published, Non-Prosecuted Patent Application DE 197 05 616 A1 discloses a lint filter device for a laundry drier, in which a first lint screen, a coarse lint filter, is followed by a second finer deep-bed filter that can be extracted from the lint filter device and can be cleaned under running water. The deep-bed filter is of foam and, therefore, has to be cleaned carefully. Furthermore, the action of the deep-bed filter amounts to nothing more than an improved filter action with respect to the lint entrained in the airflow. 
   SUMMARY OF THE INVENTION 
   It is accordingly an object of the invention to provide a laundry drier with removable filter that overcomes the hereinafore-mentioned disadvantages of the heretofore-known devices of this general type and that has an air filter with extended functionality, for which cleanability is not of such importance when a conventional fine lint filter precedes the air filter in a direction of the airflow. 
   With the foregoing and other objects in view, there is provided, in accordance with the invention, a laundry drier, including a laundry holding chamber, an airflow duct fluidically connected to the chamber for supplying an airflow to the chamber, an at least two-part foldable frame at least partially disposed in the airflow duct, and a removable filter held in the frame and disposed in the airflow duct, the filter having an insert at least one of binding and converting odorous substances in the airflow. 
   With the objects of the invention in view, there is also provided an airflow duct filter for a laundry drier having an airflow duct for conveying an airflow, including an at least two-part foldable frame to be at least partially disposed in the airflow duct of the laundry drier and a removable filter element held in the frame, the filter element to be disposed in the airflow duct, the filter element having an insert at least one of binding and converting odorous substances in the airflow. 
   According to the invention, the filter contains an insert binding and/or converting odorous substances. The material active for odorous substances may be, for example, activated charcoal and ensures that the airflow is thoroughly cleansed of odorous substances. Odorous substances that originate from laundry items in the treatment space of the laundry drier are bound or converted in the odor-binding insert. The air returning to the treatment space of the laundry drier or the air sucked in again from the surroundings is free of such odorous substances and releases the odorous substances to be removed out of the laundry items by transporting these substances to the odor-binding insert of the filter device. As such, the odorous substance fraction in the laundry items can be reduced within a relatively short period of time to such an extent that there is no longer any odor nuisance. 
   In accordance with another feature of the invention, the insert binding and/or converting odorous substances may be of a sheet-like piece of fibrous nonwoven, fibrous woven fabric, or fibrous knitted fabric, the fibers of which are provided with a covering binding and/or converting odorous substances. In the case of an appropriately durable covering, it is even possible for the odorous substances to be washed out of the fibrous material again. Such a covering may be of activated charcoal or other minerals that bind and/or convert odorous substances. A treatment of the fibrous material with catalytically active substances that can decompose odorous substances may also be advantageous. 
   The insert should have, as far as possible, no hard components, so that it can be washed in exactly the same way as normal laundry in a household washing machine, without the risk of the washing machine being damaged. 
   In accordance with a further feature of the invention, the filter may be of a sheet-like piece of fibrous nonwoven, fibrous woven fabric, or fibrous knitted fabric, the fibers of which are provided with a covering that is active with respect to odorous substances. In such a case, either the covering may be of activated charcoal or the entire insert itself may be of an activated-charcoal fibrous material. 
   In accordance with an added feature of the invention, advantageously, the laundry drier has a receptacle for holding and tensioning the insert within the airflow. The insert may, in such a case, be of a portion of a filter material capable of being manufactured in band form and thereby be made available in a very cost-effective way. 
   In accordance with an additional feature of the invention, the receptacle for the insert is advantageously removable from the household appliance to make it easier for the insert to be introduced and extracted. For such a purpose, it is particularly advantageous if the receptacle has a frame with a crossed-rib structure and a mesh-shaped holder for the insert, the meshes of which have the same spacing dimensions as the crossed-rib structure. 
   In accordance with yet another feature of the invention, the frame can be removed from the airflow duct. 
   In accordance with yet a further feature of the invention, the insert may be preceded by a fine filter for the removal of particles, preferably, of lint, from the airflow. The insert can, thus, be protected against contamination by fine particles that could clog it or impair its action. 
   Advantageously, the invention is employed in a condensation-type laundry drier, in which process air is circulated in a closed circuit and in the process-air circuit of which are disposed a heating device for warming the process air, a cooling device for cooling process air laden with moisture, the insert, and a preceding lint filter as a fine filter. In such an application, account can be taken of a frequent need of the users that is aimed at freeing the laundry of unpleasant odor substances. Such may be the case when the article of clothing has been exposed to cigarette smoke and only airing of the article of clothing is required. The odor filter is advantageously disposed, within the process-air circuit, at the point at which the best conditions for removing the odorous substances from the process air prevail. 
   Thus, for example, in the section between the cooling device and the heating device, the temperature of the process air is the lowest and the relative air humidity is the highest, and, downstream of the heating device and before contact with the laundry to be dried, the temperature is the highest and the relative air humidity is the lowest. 
   In accordance with yet an added feature of the invention, there is provided a blower disposed in the airflow duct, the laundry holding chamber, the airflow duct, and the blower forming a condensation-type laundry drier circulating the airflow in a closed airflow circuit. There are also provided a heating device is disposed in the airflow circuit for warming the airflow, a cooling device disposed in the airflow circuit for cooling the airflow laden with moisture, the insert being disposed in the airflow circuit, and a lint filter disposed in the airflow circuit upstream of the insert with respect to a direction of the airflow. 
   In accordance with a concomitant feature of the invention, a control device of the condensation-type laundry drier may advantageously be set up such that the process air can be warmed to a temperature below the temperature conventionally used for laundry drying and can be circulated. Thus, the laundry can be treated more carefully and, nevertheless, aired, while energy can also be saved due to the reduced temperature. Furthermore, the control device may be set up such that the process air can be circulated even when the cooling device is switched off. Cooling of the process air is not necessary during airing because there is no moisture to be removed from the process air and, therefore, further energy can be saved. 
   Other features that are considered as characteristic for the invention are set forth in the appended claims. 
   Although the invention is illustrated and described herein as embodied in a laundry drier with removable filter, it is, nevertheless, not intended to be limited to the details shown because various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims. 
   The construction and method of operation of the invention, however, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a diagrammatic cross-sectional view of a laundry drier according to the invention; 
       FIG. 2  is a cross-sectional view for the receptacle of the insert of  FIG. 1  along section line II—II in  FIG. 3 ; and 
       FIG. 3  is a partially fragmentary plan view of the receptacle and insert according to the invention. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Referring now to the figures of the drawings in detail and first, particularly to  FIG. 1  thereof, there is shown a household laundry drier  1  with a rotatably mounted drum  2  for receiving the laundry  5  to be dried. The drum  2  has a perforated drum bottom  14  and, on the opposite end face, a loading orifice  15  that can be closed by a door  9  articulated on the housing of the household laundry drier  1 . During operation, a blower  3  generates a dry-airflow that is conducted to a heating device  4  and subsequently through the perforated drum bottom  14  into the drum  2 . After contact with the laundry  5 , the dry airflows first through a coarse lint filter  6  in the door  9  and subsequently through a fine filter, not illustrated in any more detail, mounted in a housing  17  along the process-air duct  16  and through the insert  13  (see  FIGS. 2 and 3 ), held in a receptacle  7 , as an odor filter. The dry air is subsequently conducted to a condenser  8 , in which the dry air is cooled in order to condense laundry moisture contained therein. For such a purpose, the condenser  8  has flowing through it cooling air that is sucked in from the surroundings of the household laundry drier  1 . After flowing through the condenser  8 , the dry air is sucked in again by the blower  3 . 
   The receptacle  7 , illustrated in  FIG. 2  in cross-section and in  FIG. 3  in a plan view showing the surface of the insert  13 , serves as a holding frame for the odor filter  13 . For such a purpose, the holding frame  7  receives a sheet-like dish-shaped frame  11 , the bottom of which, as a crossed-rib structure  18 , has large orifices for the passage of the process air. A foldable holder  12  is interlocked in the frame  11 . The holder  12  may be of a high-grade steel wire mount. Its meshes have a width comparable to that of the orifices of the crossed-rib structure  18 . As a result, although the holder  12  covers substantially the entire bottom of the frame  11 , nevertheless, in the folded-down state, its orifices are congruent with the orifices in the frame  11 . An odor filter  13  in the form of a piece of nonwoven or textile material is retained (illustrated only partially in  FIG. 3 ) between the frame  11  and the holder  12 . 
   To produce the odor-binding property, the nonwoven-like or textile-like odor filter  13  is treated or covered with a substance (for example, activated charcoal) that can bind odorous substances. Preferably, the odorous substances can also be washed out of the insert  13  again to regenerate the odor-binding property and, thus, keep it suitable for permanent use. The insert  13 , therefore, has no hard components of any kind and can, therefore, be washed in a washing machine in the same way as conventional laundry. 
   The holding frame  7  can be extracted from the process-air duct  16  of the laundry drier  1  from outside, in particular, through a non-illustrated flap in the housing of the laundry drier  1  or through the supply-air orifice in the loading orifice  15  to the process-air duct  16 . The holder  12  and the frame  11  may also remain in the laundry drier if the insert  13  is accessible when the holding frame  7  is inserted. Furthermore, the insert  13  may also be connected firmly to the holder  12  or to the frame  11  and be removable together therewith. 
   The laundry drier illustrated in  FIG. 1  has a control device  10  for activating the blower  3 , the heating device  4 , and a further non-illustrated blower that supplies the condenser  8  with cooling air. The control device  10  is set up such that, in a program for airing the laundry  5 , the process air can be circulated at a reduced temperature and during the rotation of the drum  2 , the blower for the condenser  8  being switched off, so as not to cool down the process air unnecessarily. In such a case, contrary to a normal drying program, in addition to the temperature of the process air or the heating capacity of the heating device  4 , the movement of the laundry drum  2  may also be reduced.

Technology Classification (CPC): 3