GB2260770A

GB2260770A - Laundry washing machine with detergent container disposed in the door

Info

Publication number: GB2260770A
Application number: GB9221083A
Authority: GB
Inventors: Piero Durazzani
Original assignee: Zanussi Elettrodomestici SpA
Current assignee: Electrolux Zanussi Elettrodomestici SpA
Priority date: 1991-10-22
Filing date: 1992-10-07
Publication date: 1993-04-28
Anticipated expiration: 2012-10-07
Also published as: DE9214331U1; GB9221083D0; ES2065830A2; ITPN910070A0; FR2682695A1; IT1256272B; ES2065830R; ITPN910070A1; ES2065830B1; GB2260770B

Abstract

A laundry washing machine (1) comprising a washing tub (2), a drum (3) for containing the load of items to be washed (4), a door (5) opening for access to the interior of said drum, a detergent container (7) which is open upwardly, and a conduit (8) for the intake of water into the interior of the tub (2), wherein said container (7) is positioned in a recess 10 formed by a convex portion (6) of the door (5), and may be sprayed with liquid for the washing operation which is injected from a 6 suitable nozzle (10) disposed above the container (7). The lower part of the container is formed by material which is porous or with sufficiently small holes to 5 retain powdered detergent but to be permeable to dissolved detergent. <IMAGE>

Description

LAUNDRY WASHING MACHINE WITH DETERGENT CONTAINER DISPOSED IN THE DOOR OPENING The invention concerns a particular type of detergent container and distributor element for frontloading laundry washing machines, in particular for domestic use.

Front-loading laundry washing machines are known which comprise a drum contained in a washing tub and a porthole or door opening which can be opened at the front.

In such laundry washing machines, the substances used for the washing cycle, normally detergent in the prewash phase, detergent in the washing phase and other substances such as bleaching agents, softeners, perfume agents etc which are used in the subsequent phases are normally contained in a suitable cassette which can be pulled out at the front, being provided with separate compartments precisely for separately containing those substances. The latter are caused to flow into the tub by means of the jets of water which are individually directed on to the individual compartments and which dissolve and/or transport the substances contained therein at the beginning of the corresponding phases in the cycle.

That type of solution which is widespread in practice does however suffer from some disadvantages which are merely mentioned since they are well known to the man skilled in the art: - first of all it is necessary to provide the cassette with the appropriate system for selective distribution of water to the various compartments; that does not involve technical difficulties but does involve troublesome structural complications since it is necessary to adapt the washing programme to control also the selective distribution of water to the various compartments, using further mechanical or electro-mechanical means which are delicate and easily subject to damage and misalignment and in addition it is necessary correspondingly to complicate the water distribution circuit; - in addition it is well known that the methods of introducing the substances into the washing bath involve some functional disadvantages; in fact one of the more frequent disadvantages is clogging and consequential blocking of the compartments containing substances in powder form and another disadvantage is due to the fact that not all the detergent is actually used, even if it is carried away, since part of the detergent is lost in the water circuit and in particular issues from the tub through the drain hole until the water fills the subjacent drain conduits and its level rises until it reaches the level of the drain hole, in the tub.

That those disadvantages are indeed felt is demonstrated by the fact that there is a large number of patents, the aim of which is to eliminate them or moderate them in various ways and with a very wide range of structural configurations, all known to the man skilled in the art, which will not be illustrated here.

A fairly recent way of overcoming these problems is represented by the introduction of the detergent not in the conventional compartment in the front cassette by a suitable container which is free from any mechanical restraint, provided with holes for the intake of water and for the discharge of the detergent which is dissolved in that way, being known as the 'ball' which is positioned by hand among the mass of laundry before the door opening is closed.

That solution does in part resolve and moderate the above-indicated problems, but it gives to another disadvantage: In fact since the laundry to be washed is moved within the drum in a substantially rotational mode, it happens that the ball remains substantially at the centre of the mass of laundry, also due to its lower density, and thus diffuses the detergent contained therein in particular in the volume immediately around it.

While it is true that as the cycle is extended the level of the concentration of detergent is very slowly diffused uniformly throughout the entire washing bath, in the meantime and in particular in the short cycles the outward regions of the mass of the laundry suffer from an inevitable reduced level of washing efficiency because of the inadequate concentration of detergent for a good part of the washing cycle while in contrast it is found that there is an excessive concentration of detergent in the inward zones adjacent to the ball, with the disadvantage that the high level of concentration creates an excessively saturated environment such as to damage the articles in question.

That disadvantage is felt in particular when the laundry washing machine is working with a full load of laundry and thus the ball which is disposed at the centre of that load has very little freedom to move into other zones in the load of laundry, thus aggravating the above-described phenomenon.

However the use of a ball or in general direct loading of the detergent into the washing bath, as has been seen, does provide some undoubted advantages which it would be advantageous to utilise.

That aim is achieved by disposing at a fixed position a basket-type container for containing the substance to be sprayed in the bath, the features of which will be described hereinafter.

Thus, according to the present invention, there is provided a laundry washing machine comprising a washing tub, a drum containing the load of items to be washed, a door opening for access to the interior of the drum, an upwardly open detergent container, a conduit for the intake of water into the interior of the tub, wherein said container is positioned in a recess formed by an outward convexity of the profile of the door opening and the lower part of said container is formed by material which is porous or with sufficiently small holes to retain the detergent in powder form but to be permeable to the mixture formed by the dilution in water of said detergent.

It has been found that that fixed position at which the container is to be disposed is in a suitable cavity provided in the internal recess of the laundry loading porthole or door opening.

That arrangement may be provided with the structural features substantially as described with particular reference to the claims of the present patent.

The invention will be better appreciated from the following description given solely by way of non-limiting example and with reference to the accompanying drawing which shows in diagrammatic form a side view in section of a laundry washing machine according to the invention.

Referring to the drawing, it can be seen that the laundry washing machine indicated at 1 includes a washing tub 2, in the interior of which rotates a drum 3 into which the load of items 4 to be washed is introduced by way of the loading porthole or door opening 5.

The door opening 5 is shaped in such a way as to have very nearly in its central zone an outwardly curved or convex profile 6 which defines a recess in which the detergent container 7 is positioned in such a way that it can be both fixed and removable for it to be more easily filled.

The drawing shows the situation in which the invention is applied to a conventional laundry washing machine; in this case the water which falls on to the detergent container 7 can be taken from the conduit 8 for the intake of water from the system by way of the duct 9, and injected on to the container by way of a nozzle 10.

The container 7 is preferably in the form of an upwardly open basket configuration in which the lower portion for containing the detergent is formed of porous material or with holes which are sufficiently small as to retain the detergent in powder form while being permeable to the mixture formed by dilution of the detergent by the liquid which falls down on to it from above.

It has been found experimentally that this way of introducing the detergent into the tub permits all the detergent to be quickly carried away and in particular makes it possible to achieve a level of detergent concentration which is substantially constant and optimum at all points in the washing bath from the very first minutes.

Since for reasons of operating standards it is necessary for the feed of water from the water system to be protected against the possible re-intake of such water which is possibly polluted or any other liquid into the water system again, it is universally known to dispose downstream of the point at which the water is taken form the hydraulic system an arrangement which is known as an 'air trap' or equivalent which prevents such return of the liquid into the system.It is confirmed, even if the matter is entirely obvious to a man skilled in the art, that laboratory experiments have been conducted with that safety device properly installed at a position in the conduit 9 and that the reduction in pressure which occurs downstream of that device has not all compromised the results obtained in terms of carrying detergent away; in fact even with a conventional system with bowl compartments contained in a cassette in which removal of the detergent is effected by directing downwardly thereonto a jet of water coming from the safety device and thus at a limited pressure, the effectiveness in regard to carrying the detergent away and washing out the bowl compartments is good and sufficient for the required purpose.

The invention is particularly advantageous, as will be soon appreciated, if it is used in laundry washing machines which are referred to as being of the 'recirculation' type, in which therefore the load of water is not simply introduced into the tub and left there throughout the entire washing phase (possible heating and at the same time rotary movement of the drum), but in which the washing bath is continually drawn in by a suitable pump and reintroduced into the tub and over the load of washing. (The advantages of this mode of operation are known to men skilled in the art and will not be described since they are not relevant to the present invention).

In fact if the outlet nozzle 10 of the recirculation conduit is positioned over the detergent container 7, then the jet of water which is continually recirculated will spray the container throughout the entire recirculating phase, thus dissolving all the detergent contained therein and progressively transporting it into the washing bath.

A further advantage of this solution is due to the fact that continual spraying of the container 7 ensures that all of the detergent is dissolved and carried away from the container 7, thus ensuring that a single jet of limited time and range which comes form the intake conduit 8 and which is used for introducing water cannot leave part of the detergent which has not dissolved in the container.

It is apparent that that which has been described above and illustrated in the accompanying drawing has been set forth purely by way of example and that variations and modifications can be made without however departing from the scope of protection of the present invention.

Claims

1. A laundry washing machine comprising a washing tub, a drum containing the load of items to be washed, a door opening for access to the interior of the drum, an upwardly open detergent container, a conduit for the intake of water into the interior of the tub, wherein said container is positioned in a recess formed by an outward convexity of the profile of the door opening and the lower part of said container is formed by material which is porous or with sufficiently small holes to retain the detergent in powder form but to be permeable to the mixture formed by the dilution in water of said detergent.

2. A laundry washing machine according to claim 1 wherein said container is sprayed by liquid injected from a suitable nozzle above said container.

3. A laundry washing machine according to claim 2 wherein said nozzle receives the liquid from the intake conduit coming from the water system by way of the duct.

4. A laundry washing machine according to claim 2 or 3, wherein said nozzle receives the liquid from a suitable pump for recirculation of the washing liquid which draws said liquid from the interior of the tub.

5. A laundry washing machine according to any one of the preceding claims wherein the container can be disposed in a fixed position or in a removable position in the recess formed by said convexity in the wall of the door opening.

6. A laundry washing machine according to any one of the preceding claims and including a device to prevent the return of liquid into the circuit of the water system.

7. A domestic laundry washing machine according to any one of the preceding claims.

8. A laundry washing machine constructed and arranged to operate substantially as hereinbefore described with reference to and as illustrated in the accompanying drawing.