EP1127531A2

EP1127531A2 - Dishwashing machine with air cooling system

Info

Publication number: EP1127531A2
Application number: EP01100408A
Authority: EP
Inventors: Ugo Favret
Original assignee: Electrolux Zanussi Elettrodomestici SpA; Electrolux Zanussi SpA
Current assignee: Electrolux Zanussi Elettrodomestici SpA; Electrolux Zanussi SpA
Priority date: 2000-02-24
Filing date: 2001-01-08
Publication date: 2001-08-29
Also published as: ITPN20000013A1; EP1127531A3

Abstract

A reversible motor (7) drives a pump (6) and a fan (9) so as to generate, when the pump (6) takes in water from the washing vessel (4), a first flow of air (20) that cools the same motor, and to generate, during a drying phase, a second flow of air (21) that cools a vapour condensing wall (19) inside the washing vessel (4).

Description

The present invention refers to a dishwashing machine, particularly one intended for home use, provided with an air cooling system that is adapted to be used in view of promoting vapour condensation in the washing vessel during washload drying phases, as well as cooling down electro-mechanical operational organs of the machine, such as in particular the motor used to drive the washing pump, which are subject to rather intensive heating and normally require the provision of specific cool-down means.
More specifically, it is a purpose of the present invention to provide a dishwashing machine with an air cooling system which is particularly simple and rational and is further capable of ensuring an effective drying effect on the washload items through a condensation of vapours inside the washing vessel of the machine, while at the same time effectively cooling down electro-mechanical component parts of the machine that normally tend to heat up, such as for instance the motor used to drive the washing pump of the machine.
It is a further purpose of the present invention to provide a dishwashing machine of the above cited kind, in which the cooling system requires just a limited number of component parts ensuring a high degree of reliability thereof.
According to the present invention, these aims are reached in a dishwashing machine with an air cooling system featuring the characteristics as recited in the appended claims.
Features and advantages of the present invention will anyway be more readily understood from the description that is given below by way of nonlimiting example with reference to the accompanying drawings, in which:

Figures 1 and 2 are schematical, partially cross-sectional views of a preferred embodiment of the present invention, in respective operating conditions thereof; and
Figure 3 is a schematical top view of the dishwashing machine according to the present invention.

With reference to the above mentioned Figures, the dishwashing machine is preferably of the type intended for use in the home and mainly comprises, inside an outer casing 3, a washing vessel 4, which may for instance be made of sheet-metal and houses at least a rack (not shown for reasons of greater simplicity) for supporting the washload items, as well as water spray means associated therewith. These means preferably comprise at least a rotating spray arm 5 that is adapted to be supplied with water under pressure by a circulation pump 6, which is in turn adapted to take in the water collecting on the bottom of the washing vessel 4.
In a preferred manner, the pump 6 is of a centrifugal type and is driven by a reversible electric motor 7 controlled by an appropriate, per se known (and not shown, either) programme sequence control unit of the machine, which controls all of the main operative organs of the dishwashing machine, as substantially described for instance in EP-A-O 721 761.
In particular, said programme sequence control unit is adapted to control said operative organs of the machine so as to carry out functional cycles of operation including at least a hot final rinse phase and a subsequent drying phase to which the washload items are submitted. Said hot final rinse phase is carried out with the motor 7 operating so as to drive the circulation pump 6 in a first pre-set direction of rotation (Figure 1) so as to take in heated-up water from the bottom of the washing vessel 4 and deliver it under pressure onto the washload items in the form of jets 8 issued by the rotating spray arm 5. This phase is then concluded with the de-energization of the pump 6 and the energization of a motor-driven drain pump (not shown, for reasons of greater descriptive simplicity) so as to substantially let off the water from the washing vessel 4.
In the case that said circulation and drain pumps are provided as described in the afore mentioned publication EP-A-0 721 761, ie. in the case that such pumps are both driven by a single reversible motor 7 so as to be capable of being driven alternately in the two directions of rotation, the water discharge phase will take place by simply reversing the direction of rotation of the motor 7 with respect to the direction of rotation thereof during the rinse phase.
The drying phase starts then substantially with the above cited water discharge step, while the washload items release inside the washing vessel 4 vapours that must be reduced, ie. brought down, preferably by means of condensation on a cool surface inside the same washing vessel 4, so as to prevent them from releasing moisture into the surrounding ambient.
According to the present invention, the motor 7 is adapted to drive blower means so as to generate, when the circulation pump 6 is driven in a pre-determined direction of rotation to take in water from the washing vessel 4, a first flow of air that cools down the same motor, and to generate, during said drying phase, a second flow of air that cools down a vapour condensing wall 19 inside the washing vessel 4.
In a preferred manner, this is reached by means of a fan 9 of a centrifugal type, whose impeller is driven by the reversible motor 7 in the two directions of rotation. In particular, the fan 9 is provided with an inlet 19 adapted to take in ambient air through a corresponding aperture in the outer casing 3 of the machine, as well as two delivery outlets 11 and 12 that are separated from each other by a partition wall 15 and are connected to respective ducts 13 and 14.
The duct 13 extends with a portion thereof comprising outlet apertures 16, such as nozzles or the like, substantially in correspondence of the motor 7, preferably in correspondence of the stator windings 17 thereof.
The duct 14 extends with a portion thereof comprising outlet apertures 18, such as nozzles or the like, substantially in correspondence of said condensation wall 19, which is preferably formed by a corresponding surface of the washing vessel 4. In particular, the duct 14 is adapted to convey said second air flow (illustrated by the arrows 21 in Figure 2) against the outer surface of the wall 19.
The operation of the dishwashing machine according to the present invention is at this point fully apparent, so that it shall not be described here in any greater detail.
When water is present in the washing vessel 4 and the motor 7 drives the circulation pump 6 in the direction of rotation shown in Figure 1 to supply the rotating spray arm 5, ie. when the motor 7 is energized to drive its load, the fan 9 generates at its delivery side 11 the afore mentioned first flow of air 20, which is conveyed by the duct 13 towards the apertures 16 to effectively and advantageously cool down the same motor 7, thereby enhancing the efficiency and the durability thereof.
During the washload drying phase, ie. when the washing vessel 4 is substantially empty, the reversible motor 7 rotates in the opposite direction (so as illustrated in Figure 2) and the circulation pump 6 represents a substantially negligible load for the same motor. The flow of ambient air 21 generated by the fan 9, and conveyed towards the apertures 18 by the duct 14, cools down the wall 19, on the inner surface of which the vapour that develops inside the washing vessel 4 since the beginning of this drying phase is then able to effectively condense.
Noteworthy is at this point the construction and functional simplicity of the dishwashing machine according to the present invention, which, in the preferred embodiment described above, does among other things not require any means to divert the air flow generated by the fan 9.
It will be appreciated that the above described dishwashing machine may be subject to a number of modifications without departing from the scope of the present invention.
So, for instance, anyone skilled in the art is fully capable of readily appreciating that the afore cited flows of air 20 and 21 may also be obtained by means of a unidirectional fan 9 associated to appropriate controlled flow-diverting means.

Claims

Dishwashing machine comprising a washing vessel inside which vapour is present at the beginning of a phase for drying the washload items contained in the same washing vessel and adapted to be sprayed with water by means of a circulation pump driven by an electric motor, characterized in that said motor (7) is adapted to drive blowing means (9) to generate, when the circulation pump (6) is driven in a pre-determined direction of rotation so as to take in water from the washing vessel (4), a first flow of air (20) that cools the same motor, and to generate, during said drying phase, a second flow of air (21) that cools a vapour condensing wall (19) inside the washing vessel (4).
Dishwashing machine according to claim 1, characterized in that said vapour condensing wall (19) is formed by a corresponding area of said washing vessel (4).
Dishwashing machine according to claim 1, characterized in that said motor (7) is of a reversible type and is adapted to drive said blowing means (9) in the two directions of rotation, said blowing means (9) being provided with two delivery outlets (11, 12) separated from each other and connected to respective ducts (13, 14), in correspondence of which said first and said second flow of air (20, 21) are generated, respectively.
Dishwashing machine according to claim 3, characterized in that one of said ducts (13) comprises outlet apertures (16) adapted to direct said first flow of cooling air (20) towards the stator windings (17) of the motor (7).
Dishwashing machine according to claim 3, characterized in that one of said ducts (14) comprises outlet apertures (18) adapted to direct said second flow of cooling air (21) against the outer surface of said wall (19), on the inner surface of which said vapour is able to condense.