GB2105753A

GB2105753A - Washing machine

Info

Publication number: GB2105753A
Application number: GB08225847A
Authority: GB
Inventors: Rocco Galli; Alain Jean Lafille
Original assignee: Philips Gloeilampenfabrieken NV
Current assignee: Koninklijke Philips NV
Priority date: 1981-09-14
Filing date: 1982-09-10
Publication date: 1983-03-30
Also published as: ES515634A0; IT8123947A0; FR2512852B1; FR2512852A1; IT1138600B; GB2105753B; DE3231951A1; ES8308376A1

Abstract

In order to reduce detergent consumption in washing machines, means are provided which stop the pump 4 discharging the water leaving the laundry by the effect of the last centrifuging, i.e. spin-drying stage of a wash cycle, before this centrifuging stage finishes thereby leaving a residual quantity of water in the base of the tub 3 at the end of the cycle. The initial water quantity which enters the tub when the machine is again used (wash cycle) is that which carries with it most of the detergent disposed in the appropriate tray or trays 5A, 5B. However, as it encounters the residual quantity of water which, having remained for a certain time in contact with the environment, can have assumed a temperature higher than the water mains temperature, the precipitating detergent mass is able to disperse and dissolve more readily than if this residual water were not present. <IMAGE>

Description

SPECIFICATION Washing machine The invention relates to a washing machine comprising a tub, a laundry drum rotatably supported in the tub and driven by an electric motor, a discharge pump hydraulically connected to the tub and to a discharge conduit, a tray for wash additive(s) (such as a detergent) which is hydraulically connected to the tub and connectable to a water source, and a programmer for controlling the chosen working cycle, of which cycle at least one stage comprises a centrifuging stage with discharge of the water extracted by the centrifuging action.

In washing machines of this type, in which the additive, e.g. a detergent, is fed into the tub by the actual water used for the treatment (wash or prewash), and which for this purpose is made to pass through the detergent tray, the initial water entering this latter is that which transfers the largest detergent quantity into the tub. An appreciable portion of this detergent accumulates in the tub discharge section, i.e. in the zone lying below the laundry drum, and is difficult to dissolve because it is contained in a zone which is little influenced by the motion transmitted to the water by the movements of the drum.

Thus, a part of the detergent does not become used for washing the laundry, and is therefore lost during the next discharge stage of the dirty water.

Where the actual wash is preceded by a prewash, it has already been proposed to feed the water necessary for the wash in such a manner that an initial fraction (2 litres in the case of certain known washing machines) enters the tub without conveying the detergent, thus forming a layer on the base of the tub, whereas the second fraction (3 litres in the case of these washing machines) entrains the detergent with it. As has been found experimentally, the presence of the water layer on the tub base leads to good dissolving of the detergent.

This known method has two defects.

The first is that it is constructionally fairly complicated and costly. The second is that the second fraction which is fed through the tray section comprising the wash detergent is insufficient to completely convey it into the tub.

Consequently, not all the available detergent is used.

The object of the present invention is to provide improvements such as to appreciably reduce the loss of detergent, with a reduced electricity consumption and component outlay.

According to the invention, in a washing machine of the specified type, control means are provided which halt the operation of the discharge pump before the end of the final centrifuging stage of the wash cycle, so that on the base of the tub there remains a water layer which during the next wash cycle facilitates the dissolving of a new charge of additive(s).

The invention thus allows effective dissolving of the detergent used, by virtue of the presence in the tub of a pre-existing water layer and the effective removal of the detergent from the tray because an adequate water quantity is available for this latter operation.

The invention will be more apparent from the detailed description of one embodiment given hereinafter by way of non-limiting example with reference to the accompanying drawing, of which the sole Figure shows a diagrammatic vertical section through a washing machine.

In the Figure, the reference numeral 1 indicates the washing machine, which comprises a housing or structure 2, and a tub 3 which is elastically supported and cushioned in the conventional manner, and is hydraulically connected to a discharge-pump 4 and to a tray 5 into which the detergent and other wash products are placed and which is divided into two or more compartments 5A, 5B, with each of which there is associated a respective nozzle 6A, 6B from which the mains water necessary for the machine operations flows. The pump 4 is connected to a flexible discharge hose 7 which can be hooked for example on to a bath tub.

A laundry drum 8 is rotatably supported in the conventional manner in the tub 3, and on it shaft 9 which projects from the tub there is keyed a pulley 10 connected by a belt 1 1 to a pulley 12 which is directly operated by an electric motor 13 supported by the tub.

The reference numeral 14 indicates the programmer which controls the machine wash cycles set at any given time, for example by means of a keyboard or knob. The programmer (commonly known as the timer) can be of the electromechanical type such as that shown at 14, or of electronic or hybrid type. The electromechanical type is essentially formed from a set of cams operating on contactors and driven by an electric motor, for example of the synchronous type, and can also comprise electromagnetic clutches and reduction gears.

The electronic type is essentially formed from a processor comprising a memory from which the working cycle preset by means of a keyboard or knob is withdrawn and is transmitted to the power circuits of for example the electromagnetic valve or valves which govern the water flow, to the pump 4, to the motor 13, and to the electrical heating element disposed in the tub, the purpose of which is to heat the water.

Said power circuits can be controlled by any known electronic contactors. In the programmer 14, or associated therewith, there are provided means represented by way of example by cams 15, 16 cooperating with contactors 1 5A and 1 6A respectively, or by electronic devices of equivalent operation, which act on the motor 13 and on the pump 4 respectively. This action takes place as follows: It will be assumed that the wash cycle has reached its last stage, consisting of a centrifuging stage, during which the drum 8 rotates at high speed and the discharge pump 4 is in operation in order to discharge the water which is expelled from the laundry and drum 8 by centrifugal force.

Under these conditions the contactors 1 5A and 1 6A are both closed by the respective cams 15 and 16.

A certain time before the end of the centrifuging stage, for example equal to 1/5 of the entire centrifuging stage duration, this latter being constant, the cam 1 6 opens the relative contactor 1 6A so that the discharge pump 4 stops, whereas centrifuging continues. During this stage, the water leaving the laundry is not discharged but instead accumulates on the base of the tub 3.

When the centrifuging stage has proceeded for its entire duration, the contactor 1 5A is also opened so that the drum 8 stops. The machine has thus terminated Its working cycle, and comprises on the tub base in the zone below the laundry drum 8 a certain quantity of water which facilitates the dissolving of the detergent when the machine is again used in the next wash cycle. This is because when the detergent is removed from its tray 5 by the water flowing from the nozzle 6A or 6B, it already finds in the tub 3 a certain quantity of water in which it can disperse and begin to dissolve.

It is apparent that in the case of an electronic programmer, the said operating stages are controlled by functionally equivalent circuit means.

Claims

1. A washing machine comprising a tub, a laundry drum rotatably supported in the tub and driven by an electric motor, a discharge pump hydraulically connected to the tub and to a discharge conduit, a tray for wash additive(s) (such as a detergent) which is hydraulically connected to the tub and can be connected to a water source, and a programmer for controlling the wash cycle chosen at any given time, of which cycle at least one stage comprises a centrifuging stage with discharge of the water extracted by the centrifuging, characterised in that control means are provided which halt the operation of the discharge pump before the end of the final centrifuging stage of the wash cycle, so that on the base of the tub there remains a water layer which during the next machine wash cycle facilitates the dissolving of a new charge of additive(s).

2. A washing machine as claimed in Claim 1, characterised in that the control means comprise cams and contactors in an electromechanical programmer.

3. A washing machine as claimed in Claim 1, characterised in that the control means are associated with an electronic programmer.

4. A washing machine substantially as herein described with reference to the accompanying drawing.