EP1353004A1

EP1353004A1 - Washing machine with self-cleaning drying circuit

Info

Publication number: EP1353004A1
Application number: EP02425212A
Authority: EP
Inventors: Marco Righetti; Lucio Casteldelli
Original assignee: Bonferraro SpA
Current assignee: Bonferraro SpA
Priority date: 2002-04-09
Filing date: 2002-04-09
Publication date: 2003-10-15

Abstract

A washing machine provided with a drying circuit includes a fan made up of an impeller (G) enclosed by a case (T) and driven by a motor (M) to generate an air flow through the machine drum and the circuit, and also a nozzle fed through an electrovalve and arranged in said case (T) to emit a water jet (N) suitable to clean the impeller (G) at the end of the drying cycle so as to prevent the accumulation of residues such as fibers released by the clothes and detergent particles. The jet (N) is preferably oriented in the direction opposite with respect to direction of rotation of the impeller (G) which is mounted idle on the motor (M), so that the jet (N) itself causes the counter-rotation thereof during the cleaning step.

Description

The present invention relates to washing machines provided with a drying circuit, and in particular to a machine provided with a device for cleaning said circuit.
It is known that in washing machines which also carry out the drying function there is provided a drying circuit in which, at the end of the wash cycle, the air coming from the drum is passed. This circuit includes means to remove humidity from the air and to return hot and dry air to the drum to dry the laundry.
A typical drawback of these combined washing-drying machines is that due to accessibility problems they are not provided with filters in the drying circuit, whereas these are provided in drying machines. Said filters are required to stop the cloth fibers and the detergent particles which enter the circuit together with the air during the drying step.
In fact it is well known that a worn item releases fibers during the wash and these become lighter due to the drying and they may follow the air flow in the drying circuit. These fibers, together with the detergent particles, tend to deposit on the impeller of the fan which generates the air flow in the circuit.
The continuous accumulation in time of these residues causes a progressive decrease in performance of the drying system due to the reduction of the air flow rate delivered by the fan. The problem may increase until it reaches a clogging of the circuit with consequent blocking of the drying system upon intervention of the safety devices which prevent overheating (e.g. thermostat). Obviously at this moment a maintenance intervention is required to restore the drying function of the machine.
Therefore the object of the present invention is to provide a washing-drying machine which is free from said drawbacks. This object is achieved by means of a machine provided with a device for cleaning the fan impeller. Other advantageous features of the present device are disclosed in the subsequent claims.
The main advantage of the present machine is the fact that it assures drying performances constant in time thanks to the continuos cleaning of the impeller which prevents the accumulation of residues.
As a consequence, not only the required maintenance intervention are reduced but the circuit cleaning also assures that there is no alteration of the laundry smell.
Another advantage of this type of machine is that it is made with a very simple structure, which therefore results cheap to manufacture and reliable in use.
Further advantages and characteristics of the machine according to the present invention will be clear to those skilled in the art from the following detailed description of an embodiment thereof, with reference to the annexed drawings wherein:
Fig.1 is a perspective front view of the drying circuit of a machine according to the invention;
Fig.2 is a perspective rear view of said drying circuit; and
Fig.3 is a partially sectional perspective view of the portion of the drying circuit where the cleaning device is arranged.
With reference to said figures there is seen that the drying system of the present machine conventionally includes a fan made up of an impeller enclosed by a case T and driven by a motor M to generate an air flow through the drum (not illustrated) and the circuit, as indicated by the arrows. More specifically, the air coming from the drum enters the circuit through inlet E, flows up along channel C and joint A to case T, where it passes through the heating chamber H and is then returned to the drum through joint U.
The operation of the drying system is based on the condensation of vapour coming from the drum by means of water W fed through inlet V and kept suspended in channel C due to the suction effect generated by the fan. Once it has been condensed, the vapour is conveyed to the drain pump through outlet D, so that the fan receives cool and dry air which is heated in chamber H.
Here a resistor R (visible in fig.2 where the cover of chamber H has been omitted) is powered through contacts P and monitored by a safety thermostat S. It should be noted that in the last minutes of the drying cycle resistor R is turned off while the fan continues to operate to cool down the laundry which otherwise would be too hot to allow the user to extract it from the drum.
The novel aspect of the present invention is diagrammatically illustrated in fig.3, where case T is partially removed to show impeller G driven by motor M. To achieve the cleaning of impeller G there is provided a nozzle, connected to an electrovalve through a tube, which emits a measured water jet (indicated by arrow N) toward impeller G.
In particular, jet N is preferably oriented in the direction opposite with respect to the direction of rotation of impeller G and is emitted for some seconds so as to achieve the cleaning of all blades of impeller G. The latter is in fact preferably mounted idle on motor M, whereby it is jet N itself which causes its counter-rotation during the cleaning step, but a short activation of motor M could be provided as well. The sprinkled water, together with the removed residues, is then drained through outlet D and the system is ready for the following drying cycle in a perfectly clean state.
This impeller G cleaning step will in general be carried out in an automatic way at every drying cycle, but it would obviously be possible to provide so that it is carried out every given number of cycles or only upon specific command by the user.
It is clear that the above-described and illustrated embodiment of the machine according to the invention is just an example susceptible of various modifications. In particular, the shape and arrangement of the elements making up the drying circuit may be somewhat changed, same as the type of fan impeller G and/or the position of the cleaning nozzle as long as the latter is suitable to emit a jet capable of performing a complete cleaning of the impeller.

Claims

Washing machine provided with a drying circuit including a fan made up of an impeller (G) enclosed by a case (T) and driven by a motor (M) to generate an air flow through the machine drum and said circuit, characterized in that it includes a nozzle fed through an electrovalve and arranged in said case (T) to emit a water jet (N) suitable to clean said impeller (G).
Washing machine according to claim 1, characterized in that the nozzle is arranged so that the water jet (N) is oriented in the direction opposite with respect to the direction of rotation of the impeller (G).
Washing machine according to claim 1 or 2, characterized in that the impeller (G) is mounted idle on the motor (M).
Washing machine according to one or more of the preceding claims, characterized in that it includes a specific control for the activation of the electrovalve.
Operating cycle for a washing machine according to one or more of the preceding claims, characterized in that it includes at the end of the laundry drying step a cleaning step of the drying circuit through activation of the electrovalve for some seconds.
Operating cycle for a washing machine according to claim 5, characterized in that the cleaning step is carried out only every given number of drying cycles.
Operating cycle for a washing machine according to claim 4 and 5, characterized in that the cleaning step is carried out only if the user has selected it through the relevant control.