Dishwashing machine with air cooling system

Abstract

 A motor (7) drives a pump (6) and a fan (9) so as to generate a flow of air that cools the same motor when said pump (6) takes in water from the washing vessel (4), whereas it is diverted so as to cool down a vapour condensation wall (19) inside the washing vessel (4) during a washload drying phase.

Description

[0001] 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.

[0002] In this connection, a dishwashing machine has been already proposed, which is provided with an electric reversible motor driving a water circulation pump and a fan. In other words, when such a motor rotates in a direction, the circulation pump takes in water from the washing vessel of the machine in view of delivering it to the rotating spray arms of the machine and, as a result, the washload, whereas the fan generates, at a first outflow thereof, an air flow directed at cooling down the same motor.

[0003] During a washload drying phase, the motor then rotates in the reverse direction and the fan generates, at a second outflow thereof, an air flow directed at cooling down a vapour condensation wall provided inside the washing vessel.

[0004] Such a solution is particularly simple and advantageous. However, it calls for the use of an electric reversible motor, with the resulting construction and functional complications associated therewith.

[0005] Furthermore, the impeller or wheel of said fan, owing to its having to be assigned a conformation that is adapted to ensure a sufficient flow of air in both direction of rotation, has necessarily a rather low efficiency that ultimately limits the actual performance capabilities of the entire cooling system.

[0006] It therefore is a purpose of the present invention to provide a dishwashing machine with an air cooling system which not only is particularly simple and rational, but also particularly efficient.

[0007] 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.

[0008] Features and advantages of the present invention will anyway be more readily understood from the description that is given below by way of non-limiting example with reference to the accompanying drawings, in which:

• Figures 1 and 2 are schematical views of the main component parts of a dishwashing machine according to 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, in the condition illustrated in Figure 1.

[0009] 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.

[0010] In a preferred manner, the pump 6 is of the centrifugal type and is driven by a unidirectional 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.

[0011] 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 for taking in heated-up water from the bottom of the washing vessel 4 and delivering it under pressure onto the washload items in the form of jets 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.

[0012] The drying phase starts then substantially with the above cited water discharge step, and is therefore carried out under substantial absence of water in the washing vessel 4, while the washload items release inside the same washing vessel 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.

[0013] The motor 7 is adapted to also drive the blowing wheel 11 of a fan 9, or the like, which is preferably of the centrifugal type.

[0014] In particular, the fan 9 is provided with an inlet 10 adapted to take in ambient air through a corresponding aperture in the outer casing 3 of the machine, as well as a delivery outlet 12 that is capable of being selectively connected to respective ducts 13 and 14 via at least a flow diverter 15 controlled by the pump 6, as this shall be described in greater detail further on.

[0015] 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.

[0016] The duct 14 extends with a portion thereof comprising outlet apertures 18, such as nozzles or the like, substantially in correspondence of a condensation wall 19, which is preferably formed by a corresponding surface of the washing vessel 4.

[0017] The flow diverter 15 is adapted to be actuated by a control member 20 which is hydraulically connected on one side to the delivery 21 of the pump 6 via a branch duct 22 and, on the other side, is connected mechanically to the same flow diverter. In particular, said control member 20 may comprise an expansible elastic membrane 23 (or a piston or any equivalent device) which is normally in a retracted resting position shown in Figure 1, and is adapted to switch over to a expanded operating position (shown in Figure 2) when the delivery 21 of the pump 6 exerts a substantial hydraulic pressure.

[0018] 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.

[0019] When water is present in the washing vessel 4 and the motor 7 drives the circulation pump 6 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 12 the afore mentioned flow of air, 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. In this phase, in fact, the hydraulic pressure at the delivery side 21 of the pump 6 causes the membrane 23 to expand so as to cause the flow diverter 15 to move into the position shown in Figure 2, as already mentioned above.

[0020] During the washload drying phase, ie. when the washing vessel 4 is substantially empty, the motor 7 still drives the circulation pump 6, which does not suck in any liquor and therefore represents a substantially negligible load for the same motor. The flow of ambient air generated by the fan 9 is substantially conveyed towards the apertures 18 of the duct 14 and 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. In this phase, in fact, the pressure at the delivery side 21 of the pump 6 is negligible, so that both the actuating member 20 and the flow diverter 15 are able to stay in the resting position shown in Figure 1.

[0021] 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 electro-mechanical means (which are largely known to be scarcely reliable and relatively expensive) to divert the air flow generated by the fan 9. The use of a reversible electric motor along with the related control means is not required, either.

[0022] 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.

Claims

1. Dishwashing machine with air cooling system, comprising a washing vessel adapted to accommodate washload items capable of being sprayed with water by means of a circulation pump driven by an electric motor, in which vapour is present in said washing vessel at the beginning of a phase for drying said washload items, and in which said electric motor is furthermore adapted to also drive blowing means to generate an air flow adapted to cool down the same motor when the pump takes in water from the washing vessel, characterized in that said electric motor (7) is a unidirectional one and also during said washload drying phase it is adapted to drive said blowing means (9) to generate said flow of air, in which the latter, during the same washload drying phase, is substantially conveyed via flow diverter means (15) in such a manner as to cool down a vapour condensation wall (19) inside the washing vessel (4).

2. Dishwashing machine according to claim 1, characterized in that said flow diverter means (15) are controlled by said pump (6) so as to selectively send said flow of air to a first or a second duct (13, 14) to cool down the motor (7) and to cool down said wall (9), respectively.

3. Dishwashing machine according to claim 2, characterized in that said flow diverter means (15) are capable of being actuated by control means (20) that are connected hydraulically to the delivery (21) of the pump (6) and comprise at least an expansible member (23) adapted to be switched, when the pump (6) takes in water from said washing vessel (4), from a normal resting position, in which said flow of air is conveyed towards said second duct (14), over to an operating position in which said flow of air is conveyed towards said first duct (13).

Drawing