FR3117134A1 - Laundry washing method, washing machine and program implementing such a method - Google Patents

Abstract

TITLE: Process for washing laundry, washing machine and program implementing such process The present invention relates to a method for washing laundry by a washing machine comprising a tank in which a drum, containing the laundry to be washed, is driven in rotation by a drive device, the method comprising a phase of wetting the laundry, including at least: – a first step of filling the tank, up to a first filling level, – a first step of rotating the drum, – a waiting step during which the drum is stationary, for a period of at least 20 seconds,– a second tank filling stage, up to a second filling level. The invention also relates to a washing machine implementing this washing method, and a program allowing the implementation of this method on a washing machine. Abstract Figure: Figure 1

Description

Laundry washing method, washing machine and program implementing such a method

Field of the invention

The present invention relates to the field of machine washing methods, implementing several linen treatment phases.

The invention relates more particularly to the wetting phase of the laundry, at the start of a washing process.

It also relates to a laundry washing machine implementing such a method, and more particularly to a rotating drum washing machine.

It also relates to a program capable of being implemented by a control module of a washing machine to implement such a method.

Prior art

Many washing machines comprise a perforated drum containing the laundry to be washed, driven in rotation in a tank which can be filled with washing water. These laundry washing machines conventionally implement a laundry washing process, or laundry washing cycle, comprising a succession of several linen treatment phases. At the start of a washing cycle, one of the first phases is usually made up of a phase of wetting the laundry.

During this laundry wetting phase, washing water is introduced into the tub, and the drum is rotated. The linen contained in the drum therefore comes into contact with water, until it becomes wet. The laundry washing cycle can then continue with this wet laundry.

Several solutions are known for the implementation of the wetting phase of the laundry. These solutions generally aim to effectively wet the laundry, saturating it with water, while minimizing the amount of water used. It is indeed important that this quantity of water be limited, in order to reduce both the water consumption and the energy consumption of the laundry washing cycle. Such a limitation of the quantity of water implemented during the phase of wetting the linen makes it possible to contribute to conforming the washing machines to the growing requirements for saving energy and resources.

According to a known solution, the linen wetting phase can comprise several successive stages of filling the tank and rotating the drum, in order to minimize the quantity of water used for washing.

Thus, during a first filling step, the tank is filled with washing water up to a predetermined filling level. This fill level is normally relatively low, and insufficient to wet a large amount of laundry.

This first filling step is followed by a first drum rotation step, during which the drum is rotated to bring the laundry into contact with the wash water. During this step, wash water is absorbed by the laundry, which lowers the water level in the tub.

After this rotation of the drum, water is then added to the same predetermined fill level, during a second filling stage, to replace the water absorbed by the laundry.

This second filling stage is followed by a second drum rotation stage, during which the drum of the machine is rotated to put the laundry in contact with water.

Finally, during a third filling stage, called final filling, water is once again added to the drum until it reaches the same predetermined filling level.

This solution for implementing the wetting phase of the linen has several advantages.

Indeed, during the drum rotation steps, the quantity of washing water absorbed by the linen varies, in particular according to the quantity of linen and its capacity to absorb water. Thus, a large amount of laundry, or particularly absorbent laundry, absorbs more water during the rotation of the drum. As a result, the amount of wash water added during the second and third filling stages naturally adapts to the characteristics of the laundry to be wetted.

Moreover, such a solution is particularly simple and robust. It does not implement complex computer programs, which can be a source of breakdowns, and only requires simple information on the water level. Indeed, it is only necessary to know if a predetermined water level has been reached, and not to know precisely the height of water in the tank. Such information can be given by a simple, inexpensive, robust and reliable sensor.

The implementation of such a solution therefore makes it possible to optimize the quantity of water in the tank, by adapting it to the quantity of laundry and its absorption capacity. It also has the advantage of being simple to install, to program and therefore of being inexpensive in the manufacture of washing machines.

Since energy-saving requirements impose increasingly strict standards on manufacturers of washing machines, it is however necessary to develop laundry washing cycles in order to make them more economical in terms of resources, and in particular water, and energy.

Objectives of the invention

The present invention aims to improve the solutions of the prior art, by overcoming their drawbacks.

In particular, an object of the invention is to provide a washing process, or washing cycle, in a laundry washing machine, which makes it possible to optimize the quantity of washing water consumed.

A particular objective is to optimize the amount of water consumed during the laundry wetting phase of a laundry washing cycle.

An object of the invention is thus to save the energy necessary for heating the water used for washing the laundry.

Another object of the invention is to provide such a method which can be implemented by robust, reliable and inexpensive equipment, and which does not affect the reliability and robustness of the washing machine.

A particular object of the invention is to provide such a method which can be implemented easily on existing washing machines, without modifying their hardware components.

The invention also aims to provide a washing machine which implements such a process for washing clothes.

These objectives, as well as others which will appear more clearly subsequently, are achieved with the aid of a method of washing linen by a washing machine comprising a tub in which a drum, containing the linen to be washed, is driven in rotation by a drive device, this method comprising a laundry wetting phase, comprising at least:
– a first step of filling the tank with washing water, up to a first predetermined filling level,
– a first stage of rotation of the drum,
– a second step of filling the tank with washing water, up to a second predetermined filling level,
this method being characterized, according to the invention, in that the linen wetting phase also comprises, after the first stage of rotation of the drum, and before the second filling stage, a waiting stage during which the drum is stationary for a period of at least 20 seconds.

Such a waiting step, between a step of rotating the drum and the next step of filling the drum, allows the free water retained in the laundry to flow into the tub. During the next filling step, the quantity of water that must be added to reach the predetermined level is then lower, which reduces the quantity of water consumed during the filling phase. The energy needed to heat this water, in the following phases of the wash cycle, is also lower. The implementation of this solution therefore saves resources and energy.

Advantageously, the first predetermined filling level and the second predetermined filling level are identical.

The same level sensor can thus be used, which facilitates the implementation of the method.

According to an advantageous embodiment, during the waiting step, said drum is stationary, for a period of at least 30 seconds.

Such a waiting period makes it possible, in view of the experiments carried out by the inventors, to achieve substantial water savings.

Even more preferentially, during said waiting step, said drum is stationary, for a period of at least one minute.

Such a waiting period makes it possible, in view of the experiments carried out by the inventors, to achieve even greater water savings.

According to an advantageous embodiment, the linen wetting phase comprises at least:
– a first step of filling the tank with washing water, up to a first predetermined filling level,
– a first stage of rotation of the drum,
– a second step of filling the tank with washing water, up to a second predetermined filling level,
– a second stage of rotation of the drum,
– a third stage of filling the tank with washing water, up to a third predetermined filling level
and at least one waiting step, between the first rotation step and the second filling step and/or between the second rotation step and the third filling step.

Advantageously, in this case, the second predetermined filling level and the third predetermined filling level are identical.

The invention also relates to a washing machine comprising:
- a tank in which a drum, containing the laundry to be washed, is rotated by a drive device, and
- means for filling this tank with washing water,
this laundry washing machine also comprising a control module able to control at least said filling means and said drive device,
characterized in that said control module implements a washing method according to any one of the preceding claims.

Advantageously, this washing machine comprises a device for detecting a water level, able to communicate to the control module information concerning the level of washing water in the tank.

According to a preferred embodiment, this water level detection device comprises a pressure switch.

The invention also relates to a program product, able to be implemented by a control module of a washing machine comprising a tub in which a drum, containing the laundry to be washed, is driven in rotation by a device for drive, and means for filling this tank with washing water, this program implementing, when it is executed by the control module, a laundry washing process as described above.

List of Figures

• [Fig. 1] la figure 1 est une représentation schématique d'une machine à laver le linge selon un mode de réalisation de l'invention.
• [Fig. 2] la figure 2 est une représentation schématique des étapes d’une phase de mouillage de linge dans un procédé de lavage selon un mode de réalisation de l'invention.
• [Fig. 3] la figure 3 est un graphique représentant l’évolution de la quantité d’eau dans la cuve et de la vitesse de rotation du tambour au cours d’une phase de mouillage de linge dans un procédé selon un mode de réalisation de l'invention.

Description détaillée de modes de réalisation de l’invention The invention will be better understood on reading the following description of preferred embodiments, given by way of a simple figurative and non-limiting example, and accompanied by the figures among which:

• [Fig. 1] Figure 1 is a schematic representation of a washing machine according to one embodiment of the invention.
• [Fig. 2] FIG. 2 is a schematic representation of the steps of a laundry wetting phase in a washing process according to one embodiment of the invention.
• [Fig. 3] FIG. 3 is a graph representing the evolution of the quantity of water in the tank and of the speed of rotation of the drum during a laundry wetting phase in a method according to one embodiment of the invention.

Detailed Description of Embodiments of the Invention

There schematically represents a washing machine 1 according to one embodiment of the invention. This washing machine 1 comprises a tank 2, capable of containing the washing water. A pipe 21, closed by a solenoid valve 22, makes it possible to supply the tank 2 with washing water. The tank 2 is also equipped with a draining system, not represented on the , allowing it to be emptied of the liquid it contains. Finally, it contains a heating resistor 23 capable of heating the washing water that it contains.

The liquid used for wetting the laundry is referred to generically, in the present application, as "washing water". This liquid can, however, be water combined with a washing product, such as laundry detergent, or with any other product, without this affecting the invention described.

A drum 3, of cylindrical shape, is mounted in the tank 2, pivoting about an axis 31. This drum 3 can be driven in rotation controlled by a drive device, not shown. This drum 3 is designed to contain laundry 5 intended to be washed. Conventionally, this drum is perforated, which means that the water present in the tank 2, outside the drum 3, can penetrate without restriction inside the drum 3.

The tank 2 is also equipped with a device for detecting a water level, which can be constituted by any level sensor known to those skilled in the art. In the embodiment shown, this device for detecting a water level consists of a pressure switch 4 associated with a compression chamber 41 communicating with the tank 2. The pressure switch is connected to the compression chamber via a small diameter hose forming a pressure switch pipe 42.

Pressure switch 4 is an electrical contactor which changes state under the effect of pressure exerted on a flexible membrane. When the wash water level rises in tank 2, the air pressure increases in the compression chamber 41 and in the pressure switch pipe 42. This trapped air exerts pressure on the flexible membrane of the pressure switch 4.

When the water level in tank 2 reaches a predetermined level represented by the dotted line 40, which corresponds to the high level of the washing cycle, the flexible membrane of the pressure switch 4 is subjected to sufficient pressure to press on a needle of the pressure switch and flip the contactor. In the embodiment shown, this switching of the contactor causes the closing of the solenoid valve 22.

The use of a pressure switch in a washing machine is very common and particularly advantageous. Indeed, such sensors are particularly simple, inexpensive and robust. They do not make it possible to follow very precisely the evolution of the water level, but generate a signal when the water level reaches the high level. In this case, this pressure switch 4 is configured so as to emit a signal when the water level reaches, in the tank 2, the level represented by the dotted lines 40 on the .

In other possible embodiments of the invention, the level detection device can be a sensor of another type. For example, this level detection device may consist of an analog pressure switch which delivers an electrical signal proportional to the water level in the tank. A predefined water level in the tank then corresponds to a predefined value of the electrical signal provided by the pressure switch. It is thus possible, with such an analog pressure switch, to detect the overrun of several distinct predefined levels, or even to follow in real time the evolution of the level of washing water in the tank.

The washing machine 1 is designed for the implementation of a washing process, or washing cycle. It comprises for this a control module (not shown), capable in particular of controlling the solenoid valve 22 and the drive device of the drum 3, and of receiving the signals from the pressure switch 4. This control module implements a program of control, which can be likened to a computer program, allowing the implementation by the washing machine 1 of the washing process, or washing cycle.

The washing process, or washing cycle, comprises several phases, and in particular a phase of wetting the laundry during which the following steps are implemented successively:
- a first step of filling the tank 2, by opening the solenoid valve 22, until the signal emitted by the pressure switch 4 indicates that the washing water in the tank reaches the predetermined level 40,
- a first stage of rotation of the drum 3, in order to wet the linen 5 in the washing water contained in the tank 2,
- a second step of filling the tank 2, by opening the solenoid valve 22, until the signal emitted by the pressure switch 4 indicates that the washing water in the tank reaches the predetermined level 40,
- a second stage of rotation of the drum 3, and
- a third step of filling the tank 2, by opening the solenoid valve 22, until the signal emitted by the pressure switch 4 indicates that the washing water in the tank reaches the predetermined level 40.

According to the invention, the laundry washing process is modified, compared to the processes of the prior art, to introduce one or more waiting steps during the laundry wetting phase. There schematically represents the succession of steps implemented during such a laundry wetting phase, in a washing process according to one embodiment of the invention.

There represents two curves: a first curve 81 is representative of the quantity of water contained at the bottom of the tank 2 during the implementation of the linen wetting phase, and the curve 82 is representative of the speed of rotation of the drum 3 during the implementation of the laundry wetting phase.

Thus, according to a possible embodiment of the invention, the laundry wetting phase implemented by the washing machine 1 comprises the steps described below.

The wetting phase begins with a first stage of filling 91 of the tank, during which the solenoid valve 22 is open until the signal emitted by the pressure switch 4 indicates that the washing water in the tank reaches the predetermined level 40. As curve 81 shows, the quantity of water at the bottom of the tank increases rapidly during this stage, until it reaches the predetermined level 40.

This filling stage is followed by a first stage of rotation of the drum 92. During this first phase of rotation of the drum 92, the quantity of water at the bottom of the tank decreases due to the absorption of water from washing by the linen which is brewed.

In the embodiment shown, the duration of this rotation step is predetermined. It can however be provided, in other embodiments, that this step ends when the level of water in the tank reaches a predetermined low level. Furthermore, in the embodiment shown, this first stage 92 of rotation of the drum begins after the end of the first filling stage 91. Thus, it is avoided that the rotation of the drum disturbs the water level and thus the reading the wash water level in the tub. It could however be provided, in other embodiments, that this first stage of rotation of the drum 92 begins before the end of the first filling step 91, and that these two steps overlap at least partially. Finally, if the curve 82 shows a constant rotation speed of the drum during this first stage of rotation of the drum 92, it is also possible that the rotation of the drum is variable, or that the rotation is intermittent, for example by alternating rotations in different directions.

At the end of this first rotation stage, the wetting phase continues with a first waiting stage 93, lasting 30 seconds, during which the drum 3 is stationary. During this first waiting phase 93, the quantity of washing water at the bottom of the tank 2 again increases slightly, due to the flow into the tank 2 of the free water retained by the laundry 5. To have significant efficiency, this waiting phase must last at least 20 seconds. A longer duration, for example one minute, can further improve its effectiveness.

At the end of this first waiting step, the wetting phase continues with a second filling step 94 of the tank, during which the solenoid valve 22 is open until the signal emitted by the pressure switch 4 indicates that the washing water in the tub reaches the predetermined level 40. As shown by curve 81, the amount of water at the bottom of the tub increases again rapidly during this stage, until it reaches the level predetermined 40.

This second filling stage is followed by a second stage of rotation of the drum 95, during which the quantity of water at the bottom of the tank decreases again slightly due to the absorption of the washing water by the laundry. .

At the end of this first rotation stage, the wetting phase continues with a second waiting stage 96, lasting 30 seconds, during which the drum 3 is stationary. During this second waiting step 96, the water level rises slightly due to the flow into the tank of the free water contained in the laundry.

Finally, at the end of this first waiting step, the wetting phase ends with a third filling step 94 of the tank, during which the solenoid valve 22 is open until the signal emitted by the pressure switch 4 indicates that the washing water in the tub reaches the predetermined level 40.

The introduction of such waiting steps, between a step of rotating the drum and the following step of filling the drum up to a predetermined level, is particularly advantageous. Indeed, it allows the free water, which can be retained in the laundry 5 without having been absorbed by this laundry, to flow into the tank 2.

During the filling step following this waiting step, the amount of water that must be added for the washing water level to reach the predetermined level 40 is then lower than if the filling step had followed immediately. the drum rotation stage, without the free water retained by the laundry having time to flow into tank 2.

The quantity of water consumed during the filling phase is therefore lower. Moreover, since this quantity of water is lower, the energy required to heat this water, in the following phases of the wash cycle, is lower. The implementation of the solution of the invention therefore allows a saving of resources and energy.

The introduction of these waiting steps during the filling phase may raise fears of extending the overall duration of the washing cycle, which seems detrimental. However, the inventors have observed that this overall duration was not necessarily lengthened, and could even be slightly shortened by the introduction of these waiting steps. Indeed, the amount of water used for washing being lower, the heating time of this water is shortened.

By way of example, the inventors have compared two washing cycles carried out by the same machine, loaded with the same laundry, under identical conditions. The first washing cycle included a wetting phase comprising three successive filling steps, separated by drum rotation steps, without waiting steps. The second washing cycle included a wetting phase comprising three successive filling steps, separated by drum rotation steps, followed by waiting steps.

During the first wash cycle,
- the first filling stage consumed 9.1 liters of washing water,
- the second filling step consumed 3 liters of washing water,
- the third filling stage consumed 1.3 liters of washing water.
The quantity of washing water consumed during the filling phase was therefore 13.4 liters. The energy consumed during this wash cycle, including the energy for heating the wash water, was 0.673 kWh. This heating of the wash water lasted 11'36'', and the total wash cycle lasted 159'.

During the second washing cycle, implementing the waiting steps according to the invention,
- the first filling stage consumed 9.2 liters of washing water,
- the second filling step consumed 2.2 liters of washing water,
- the third filling stage consumed 1.1 liters of washing water.
The quantity of washing water consumed during the filling phase was therefore 12.5 litres. The energy consumed during this wash cycle, including the energy for heating the wash water, was 0.560 kWh. This heating of the wash water lasted 7'28'', and the total wash cycle lasted 157'.

Thus, the addition, during the wetting phase of the linen, of the waiting stages according to the invention makes it possible to achieve a saving of 0.9 liters on the consumption of washing water, to reduce the heating time and achieve a saving of 0.113 kWh. Furthermore, the inventors have verified that this modification of the washing cycle does not lead to any degradation of the laundry washing performance.

In the preferred embodiment of the invention described above, the wetting phase has three successive filling steps, separated from each other by drum rotation steps followed by waiting steps.

It is however possible to implement the invention advantageously with a filling phase which would comprise only two successive filling steps, separated from each other by a step of rotation of the drum followed by a step of 'waiting. It would also be possible to implement it with a filling phase which would comprise more than three successive filling steps.

Furthermore, it would also be possible, during a laundry wetting phase comprising more than two successive filling phases, for one or more filling steps to be followed by a drum rotation step itself followed by a waiting step, before the next filling phase, while one or more other filling steps would be followed by a drum rotation step, without a waiting step before the next filling phase.

Such embodiments can make it possible, in certain cases, to obtain at least part of the advantages of the present invention.

Claims (10)

Method of washing laundry by a washing machine comprising a tank in which a drum, containing the laundry to be washed, is rotated by a drive device,
said method comprising a laundry wetting phase, comprising at least:
– a first step of filling said tank with washing water, up to a first predetermined filling level,
– a first stage of rotation of the drum,
– a second step of filling said tank with washing water, up to a second predetermined filling level,
characterized in that said laundry wetting phase also comprises , after said first drum rotation step, and before said second filling step, a waiting step during which said drum is immobile, for a period of at least 20 seconds. Washing method according to the preceding claim, characterized in that said first predetermined filling level and said second predetermined filling level are identical. Washing method according to any one of the preceding claims, characterized in that, during the said waiting step, the said drum is stationary, for a period of at least 30 seconds. Washing method according to the preceding claim, characterized in that, during said waiting step, said drum is stationary, for a period of at least one minute. Washing process according to any one of the preceding claims, characterized in that the said laundry wetting phase comprises at least:
– a first step of filling said tank with washing water, up to a first predetermined filling level,
– a first stage of rotation of the drum,
– a second step of filling said tank with washing water, up to a second predetermined filling level,
– a second stage of rotation of the drum,
– a third step of filling said tank with washing water, up to a third predetermined filling level
and at least one waiting step, between said first rotation step and said second filling step and/or between said second rotation step and said third filling step. Washing method according to the preceding claim, characterized in that said first predetermined filling level, said second predetermined filling level and said third predetermined filling level are identical. Washing machine including:
- a tank in which a drum, containing the laundry to be washed, is rotated by a drive device, and
- means for filling this tank with washing water,
said laundry washing machine also comprising a control module able to control at least said filling means and said drive device,
characterized in that said control module implements a washing method according to any one of the preceding claims. Washing machine according to the preceding claim, characterized in that it comprises a device for detecting a level of water, able to communicate to said control module information concerning the level of washing water in said tub. Clothes washing machine according to the preceding claim, characterized in that the said device for detecting a level of water comprises a pressure switch. Program product, capable of being implemented by a control module of a laundry washing machine comprising a tub in which a drum, containing the laundry to be washed, is driven in rotation by a drive device, and means filling this tank with washing water,
said program implementing, when executed by said control module, a laundry washing process according to any one of claims 1 to 6.