Air-exhaust type clothes tumble drier

Abstract: Clothes drier comprising, within an outer casing (1), a rotating drum (6) adapted to be loaded with the clothes and any other possible items to be dried, means (11) for heating, means (10, 12) for forcing the air to flow through the drum (6), means (15) for exhausting the air from the drier upon said air having become saturated, inside the drum (6), with the moisture contained in the clothes being dried. The present invention calls for filtering means (22), adapted to retain impurities carried by or anyway contained in the air taken in from the environment of the room where the appliance is installed, to be inserted along the flow-path (10) comprised between the air intake zone (21) of the appliance and the zone (13) at which said air enters the drum (6).

Description: The present invention refers to a tumble drier for clothes and other items, in particular an exhaust-type tumble drier. A tumble drier comprises a substantially parallelepiped outer casing in which there is enclosed a drum that, driven by an electric motor via a driving belt, is adapted to rotate according to a more or less horizontal axis. The items to be dried are loaded in the drum through a door mounted on the front wall or the top wall of said outer casing. In an exhaust-type tumble drier, a fan, located inside the outer casing, takes in fresh air from the room in which the appliance is installed and forces it into the drum after it has been duly heated up by electric heating means or gas burners that are also provided inside the outer casing of the appliance. The hot air is forced to flow through the interior of the drum, becomes saturated with the humidity it subtracts from the items loaded in the drum, which are in this way progressively dried, and is finally exhausted from the appliance. It is fully apparent that the airborne impurities that are present in the installation room are taken in into the appliance along with the drying air. In particular, since in currently used driers the air intake occurs through apertures provided in the lower portion of the outer casing, eg. through the rear wall, the base of the appliance or even the zone below the loading door when the latter is attached to the front wall, further to such contaminants as cigarette smoke, odours generated during cooking (if the appliance is installed in a kitchen) or even possible airborne germs, ie. germs that can be transmitted by air, particularly significant, among airborne impurities in general, are the dust rolls or clots that form on the floor. In all cases, such impurities eventually come into contact with the items loaded in the drum for drying, and this of course has clear negative effects, in particular if such items are constituted by clothes made of silk, sponge cloth or similar fabrics. It would therefore be desirable, and is actually a main purpose of the present invention, to provide means adapted to prevent, in an appliance of the above cited kind, the items to be dried from coming into contact with impurities that are taken in with the drying air from the installation room. According to the present invention, such aim is reached in a tumble drier for the clothes and other items comprising, inside an outer casing with a worktop and a front panel, a rotating drum adapted to be loaded with the items to be dried, heating means as well as means capable of ensuring a forced circulation of air through the drum, means for exhausting the saturated air from the drier, and filtering means adapted to retain the impurities carried by the air before said air flows into the drum, said filtering means are associated to a drawer arranged in a removable way in an air intake conduit for taking in drying air from the outside of said outer casing and extending below the worktop in correspondence to the upper part of the appliance. The Applicant is of course fully aware of the fact that the use of a filter for the drying air in clothes tumble driers is well-known in the art, for instance from the disclosures in US-A-3 579 851 and WO-A-9508016. This filter, however, is used to the sole purpose of retaining lint and, as a result, it is accordingly arranged in the zone in which the air flows out of the drum. DE 195 42 597 discloses an air-exhaust type laundry drier comprising an suction duct located on the lower portion of the appliance and provided with filtering means for the drying air, and a blow duct for exhausting the moisture-laden air leaving the drum. The filtering means include a filter mat fitted to the suction duct inlet provided on the front wall of the appliance outer casing below the loading door. The filter mat is arranged behind a grating, which closes the suction duct. US 5 822 883 refers to a clothes dryer dedicated to drying garments to be worn in clean room environments wherein the inlet air to the clean room is extensively filtered. The clothes dryer provides a tumble dryer comprising an enclosure having a rotatable drum for receiving and tumbling garments, a fan and motor assembly for providing airflow through the drum, an exhaust duct near the drum, a particle counter assembly having a sampling tube in the exhaust duct, the particle counter for measuring the concentration of particles in the sample, and a unit for producing an output signal indicating the concentration of particles in the sample. GB 2 262 595 discloses a laundry washing and drying machine, comprising means to realise the washing, including a washing agent distributor, and means to realise the drying by way circulating hot air, including a filtering element for said hot air. The filtering element of the air, arranged in the drying circuit of the closed type, is integrated in the washing agent distributor. US 2 644 246 relates to a clothes dryer of the domestic air circulating type provided with a lint trap for the discharge outlet in which a primary lint collecting screen is pivotally mounted at opposite sides of an outlet duct, so that when considerable lint has accumulated on the screen, the lint screen offers sufficient resistance to the passage of air through the outlet duct that is tilted forward to a substantially horizontal position, in which position the accumulated lint will be blown off its surface. DE 91 04 967 U refers to an air-exhaust type laundry drier comprising a fan and motor assembly for drawing air from the outside of the appliance and into the drum where the saturated air is discharged through a filter which is a part of the loading door. The fan is located in correspondence with the base of the appliance where the outer casing is provided, at the lower frontal part below the loading door, with a pocket or undercut including a filter device through which the drying air is taken in. The filter device comprises a filter bag pull-out from the pocket by removing an fastening flange or frame integrally formed with the casing. DE 44 22 602 discloses a drying chamber ventilation useful for energy-saving. The process comprises measuring the air conditioning data of the chamber and the adjoining inner space. A fan for the aeration or deaeration of the space is controlled in a way that results in optimum drying results. Filtering means are provided for the drying air taken in from outside the chamber. DE 41 25 138 relates to a clothes airing unit adapted to be installed into a cupboard incorporating a supply air and waste air cleaning facility. The supply air and waste air are guided through carbon and dust filters for absorbing unpleasant smells. The air current is produced by means of a ventilator. In order to enable features and advantages of the present invention to be more readily and clearly understood, a description of a preferred embodiment is given below by way of non-limiting example with reference to the accompanying drawings, in which: Figure 1 is a partially see-through view of an exhaust-type clothes tumble drier for household use, in its operating configuration; Figure 2 is a similar view as the one appearing in Figure 1, but for the appliance which is illustrated here in its maintenance or cleaning configuration. In a largely well-known manner, the tumble drier illustrated in the above cited Figures comprises a substantially parallelepiped outer casing 1 with a worktop 2, a front panel 3 carrying the control organs 4, 5. Inside the outer casing 1 there is arranged a metal drum 6 that is adapted to be driven rotatably about a more or less horizontal axis X by an electric motor via a drive belt (for reasons of greater simplicity, these last items are not shown in the Figures). As far as the loading and unloading of the items to be dried is concerned, the aperture of the front flange 7 of the drum 6 is capable of being closed by a rectangular door 8 that is hinged on to the front wall 9 of the outer casing 1. According to a feature of the present invention, the air is taken in from the room in which the drier is installed by a motor-driven fan (not shown in the Figures, but anyway arranged in the lower front zone of the outer casing 1) through an intake aperture 21 which is part of a pull-out drawer 20 that is accessible from the front panel 3. The air is forced to flow through a first horizontal conduit 10 provided immediately below the worktop 2 and, in a sequence, an electric heating unit 11 and a second vertical conduit 12 provided therebelow. After having so been heated up, the air is then blown into the drum 6 through a plurality of perforations 13 provided in the rear flange 14 thereof. Upon becoming saturated with the humidity it removes from the items to be dried (not shown) as it flows across the drum of the drier, the hot air leaves the drum 6 through an annular aperture which, duly provided with a lint filter, is located on the inside, ie. the liner of the door 8. The moisture-laden, hot air is then conveyed through a third conduit (not shown, like the afore cited annular aperture and the lint filter)) up to a final aperture 15 located in the lowest portion of the left wall 16 of the outer casing 1. To this aperture 15 there may be attached a flexible hose (not shown, either) in order to definitively exhaust the air outside the building in which the drier is installed. The drawer 20, with the intake aperture 21 for the drying air, occupies in the front panel 3 the same position that is usually occupied by the detergent dispenser drawer in a household washing machine (or, for the matter, the same position as the reservoir provided to collect condensation water in many models of the closed-loop condenser-type clothes driers in use today) and, by taking advantage of an appropriately provided undercut, it can be removed with a single hand that pulls it out in the direction shown by the arrow in Figure 2, eg. for performing the cleaning and maintenance operations described further on. According to the main feature of the present invention, on the opposite side of the aperture 21 the box-like body of the drawer 20 sustains a frame 23 that is capable of swinging thanks to its being hinged along its lower edge. In turn, the frame 23 sustains filtering means 22 for the drying air. This construction is such as to ensure that, when the drawer 20 is pushed in, ie. closed, the frame 23 abuts against a flange 24 provided at the end of an initial portion 25 of said first conduit 10 and, as a result, the air taken in by the fan is capable to actually and effectively flow through the filtering means 22 which, in view of a greater efficiency and durability thereof, are provided in an inclined arrangement with respect to the air flow. Although the intake aperture 21 provided on the front panel 3 for the drying air is practically such as to be able to prevent dust clots or rolls from being sucked into the drier (particularly if the latter is a built-in model), so that the filtering means 22 might also consist of a simple (and unexpensive) paper filter of the dust-bag type used in vacuum cleaners, in a preferred embodiment of the present invention such filtering means 22 consist of a partition of a material (eg. a polypropylene electret) adapted to retain dust particles, associated to an activated-carbon mat adapted to absorb detrimental gaseous substances contained in the air. Upon simply pulling out said drawer 20, said filtering means 22 can therefore be inspected and, if needed, submitted to the required maintenance, ie. cleaning, regeneration and even replacement, even by the user him/herself (see Figure 2). From the above description, the most significant advantages of the present invention can therefore be inferred to derive from: a) the drying air being cleaned by the filtering means 22 before entering the drum of the drier and coming into contact with the therein loaded items to be dried, which are in this way practically no longer subject to any more or less serious form of contamination due to impurities taken in with the air from the installation room during the drying process; b) the short distance from the intake aperture 21 for the drying air and the heating unit 11 making it possible for the temperature of the drum 6 and the drying load in the same drum to rise to the desired value and reach steady-state conditions in a much quicker manner, thereby making it possible for the overall duration of the drying cycle to be reduced accordingly; c) the filtering means 22 being arranged in the drawer 20 so as to make inspection and any possible cleaning and/or maintenance thereof much more convenient to be carried out; d) solid particles, eg. dust particles, that may be present in the air taken in from the installation room being effectively prevented from possibly depositing onto the resistance wires of the heating unit 11, thereby eliminating the associated risk of causing the same wires to burn out or the heating unit 11 itself to suffer some damage; e) the position of the air intake aperture 21 in the front panel 3 allowing, if required or considered appropriate, for the use of low-cost filtering means 22. It will be appreciated that, on the basis of the innovatory concept introduced by the present invention, the drier may also be implemented in forms and with details differing from the above described and illustrated ones without departing from the scope of the present invention. In particular, the drier can have its loading door attached to the top wall of the outer casing.

Claims: Tumble drier for clothes and other items comprising, inside an outer casing (1) with a worktop (2) and a front panel (3) carrying control organs (4, 5), a rotating drum (6) adapted to be loaded with the items to be dried, heating means (11) as well as means (10, 12) capable of ensuring a forced circulation of air through the drum (6), means (15) for exhausting the air from the drier after that, inside the drum (6), it has become saturated with the humidity subtracted from the drying items, and filtering means (22) adapted to retain the impurities carried by the air or present in the air taken in from the room in which the appliance is installed before said air flows into the drum (6) characterized in that said filtering means (22) are associated to a drawer (20) arranged in a removable way in an air intake conduit (10) for taking in drying air from the outside of said outer casing and extending below the worktop (2) in correspondence to the upper part of the appliance. Tumble drier according to claim 1, characterized in that said drawer (20) consists of a box-like body sustaining a frame (23) that in turn sustains said filtering means (22), said drawer is accessible from the front panel (3) and can be removed from the intake conduit (10) of the appliance even by the user. Tumble drier according to claim 2, characterized in that said box-like body of the drawer (20) comprises an air intake aperture (21) through which the air is taken in from outside the appliance and flows in the intake conduit (10). Tumble drier according to claim 2 or 3, characterized in that said frame (23) and, therefore, also the filtering means (22) are capable of swinging owing to their being hinged on to the box-like body of said drawer (20). Tumble drier according to claim 4, characterized in that when said drawer (20) is positioned in the intake conduit (10), said frame (23) abuts against a flange (24) provided at the end of an initial portion (25) of said intake conduit (10) in order to said filtering means (22) are provide in an inclined arrangement with respect to the air flow. Tumble drier according to any of the preceding claims, characterized in that said filtering means (22) consist of a partition plate made of materials that are capable of retaining the solid particles, and associated with a corresponding mat made of materials capable of absorbing the detrimental gaseous substances that may be present in the air. Tumble drier according to any of the preceding claims, characterized in that said filtering means (22) consist of a partition plate made of filter paper.

Inventors: VALENT LUCIO, VALENT, LUCIO
Applicants: ELECTROLUX HOME PRODUCTS ITALY, ELECTROLUX HOME PRODUCTS ITALY S.P.A.
Application year: 1999
Main classification: D06F58
IPC codes: D06F58